1) Biosensors are devices that use biological or chemical reactions to measure analytes by generating signals proportional to analyte concentration. They are used in applications like disease monitoring, drug discovery, and pollution detection.
2) A biosensor consists of a bioreceptor that recognizes the analyte, a transducer that converts the biorecognition into a measurable signal, electronics that process the signal, and a display that shows the results.
3) Important characteristics of biosensors include selectivity for the target analyte, reproducibility of results, stability over time and varying conditions, high sensitivity to detect low analyte levels, and a linear response over different analyte concentrations.
This a short and efficient presentation On Biosensor for giving presentation in the upcoming seminar....
This could be more edited further for future purposes......
Contact: arnabguptakabiraj@gmail.com
This is for the beginners level giving presentation for the first time....
Biosenser are now a days a very helpful device which have various application in the field of medical in this presentation i described about biosensors and their types major application of biosensors
A biosensor is an analytical device containing an immobilized biological material (enzyme, antibody, nucleic acid, hormone, organelle or whole cell) which can specifically interact with an analyte and produce physical, chemical or electrical signals that can be measured. An analyte is a compound (e.g. glucose, urea, drug, pesticide) whose concentration has to be measured.
A Descriptive Review over the field of Biosensors has been given here; its origin history events; its working principle; its classification based on various parameters; applications and future scope
Biosensors are the analytical device that are used to measure the concentration of analye , these type of biosensors are made with conjugation of enzymes as a biological eliment to quantify a (bio)chemical substance / analyte are reffered to as Enzyme-probe Biosensors .
Biosensors are of many types but focusing on Enzyme biosensors there are 4 main types which are briefly described in this power point presentation .
biosensor, modern, principles, technology, applications, working of sensor, types of sensor , nanomaterial, based biosensor(nanosensor) optical biosensor, flourescent biosensor, electrochemical and glucose biosensor, genetically encoded biosensor, microbial biosensor, cancer , references included, advantages and disadvantages also included.
Cholesterol Bio Sensors: getter better fastJeffrey Funk
These slides use concepts from my (Jeff Funk) course entitled analyzing hi-tech opportunities to analyze the increasing economic feasibility of bio-sensors for measuring cholesterol in humans. Bio-sensors detect the level of cholesterol (and other biological materials) using enzymes, matrices, and transducers. The enzymes, which are held in a matrix, react with the cholesterol and an electric signal is produced from an amperometric transducer. Improvements in sensitivity, response time, shelf life, detection limit, and reusability have been achieved through creating more appropriate biological materials for the enzymes, matrices, and transducers.
A biosensor is an analytical device which converts a biological response into an electrical signal. The term biosensor is often used to cover sensor devices used in order to determine the concentration of substances and other parameters of biological interest even where they do not utilize a biological system directly. Biosensors have become essential analytical tools, since they offer higher performance in terms of sensitivity and selectivity than any other currently available diagnostic tool. With appropriate progress in research, biosensors will have an important impact on environmental monitoring, reducing cost and increasing efficiency. Biosensors represent a rapidly expanding field, at the present time, with an estimated 60% annual growth rate; where major focus is on health care industry. Although there use is unquestionable in the field of agri food, research, security and defence. In this paper various aspects of biosensors have been touched.
This a short and efficient presentation On Biosensor for giving presentation in the upcoming seminar....
This could be more edited further for future purposes......
Contact: arnabguptakabiraj@gmail.com
This is for the beginners level giving presentation for the first time....
Biosenser are now a days a very helpful device which have various application in the field of medical in this presentation i described about biosensors and their types major application of biosensors
A biosensor is an analytical device containing an immobilized biological material (enzyme, antibody, nucleic acid, hormone, organelle or whole cell) which can specifically interact with an analyte and produce physical, chemical or electrical signals that can be measured. An analyte is a compound (e.g. glucose, urea, drug, pesticide) whose concentration has to be measured.
A Descriptive Review over the field of Biosensors has been given here; its origin history events; its working principle; its classification based on various parameters; applications and future scope
Biosensors are the analytical device that are used to measure the concentration of analye , these type of biosensors are made with conjugation of enzymes as a biological eliment to quantify a (bio)chemical substance / analyte are reffered to as Enzyme-probe Biosensors .
Biosensors are of many types but focusing on Enzyme biosensors there are 4 main types which are briefly described in this power point presentation .
biosensor, modern, principles, technology, applications, working of sensor, types of sensor , nanomaterial, based biosensor(nanosensor) optical biosensor, flourescent biosensor, electrochemical and glucose biosensor, genetically encoded biosensor, microbial biosensor, cancer , references included, advantages and disadvantages also included.
Cholesterol Bio Sensors: getter better fastJeffrey Funk
These slides use concepts from my (Jeff Funk) course entitled analyzing hi-tech opportunities to analyze the increasing economic feasibility of bio-sensors for measuring cholesterol in humans. Bio-sensors detect the level of cholesterol (and other biological materials) using enzymes, matrices, and transducers. The enzymes, which are held in a matrix, react with the cholesterol and an electric signal is produced from an amperometric transducer. Improvements in sensitivity, response time, shelf life, detection limit, and reusability have been achieved through creating more appropriate biological materials for the enzymes, matrices, and transducers.
A biosensor is an analytical device which converts a biological response into an electrical signal. The term biosensor is often used to cover sensor devices used in order to determine the concentration of substances and other parameters of biological interest even where they do not utilize a biological system directly. Biosensors have become essential analytical tools, since they offer higher performance in terms of sensitivity and selectivity than any other currently available diagnostic tool. With appropriate progress in research, biosensors will have an important impact on environmental monitoring, reducing cost and increasing efficiency. Biosensors represent a rapidly expanding field, at the present time, with an estimated 60% annual growth rate; where major focus is on health care industry. Although there use is unquestionable in the field of agri food, research, security and defence. In this paper various aspects of biosensors have been touched.
Biosensors are nowadays ubiquitous in biomedical diagnosis as well as a wide range of other areas such as point-of-care monitoring of treatment and disease progression, environmental monitoring, food control, drug discovery, forensics and biomedical research. A wide range of techniques can be used for the development of biosensors. Their coupling with high-affinity biomolecules allows the sensitive and selective detection of a range of analytes. We give a general introduction to biosensors and biosensing technologies, including a brief historical overview, introducing key developments in the field and illustrating the breadth of biomolecular sensing strategies and the expansion of nanotechnological approaches that are now available
The revolution of nanotechnology in molecular biology gives an opportunity to detect and manipulate atoms and molecules at the molecular and cellular level.
A biosensor is an analytical device which converts a biological response into an electrical signal. The term
'biosensor' is often used to cover sensor devices used in order to determine the concentration of substances and
other parameters of biological interest even where they do not utilize a biological system directly. This very
broad definition is used by some scientific journals (e.g. Biosensors, Elsevier Applied Science) but will not be
applied to the coverage here. The emphasis of this Chapter concerns enzymes as the biologically responsive
material, but it should be recognized that other biological systems may be utilized by biosensors, for example,
whole cell metabolism, ligand binding and the antibody-antigen reaction. Biosensors represent a rapidly
expanding field, at the present time, with an estimated 60% annual growth rate; the major impetus coming from
the health-care industry (e.g. 6% of the western world are diabetic and would benefit from the availability of a
rapid, accurate and simple biosensor for glucose) but with some pressure from other areas, such as food quality
appraisal and environmental monitoring. The estimated world analytical market is about 12,000,000,000 year-
1
of which 30% is in the health care area. There is clearly a vast market expansion potential as less than 0.1% of
this market is currently using biosensors. Research and development in this field is wide and multidisciplinary,
spanning biochemistry, bioreactor science, physical chemistry, electrochemistry, electronics and software
engineering. Most of this current endeavour concerns potentiometric and amperometric biosensors and
colorimetric paper enzyme strips. However, all the main transducer types are likely to be thoroughly examined,
for use in biosensors, over the next few years
Biosensors: General Principles and ApplicationsBhatt Eshfaq
A biosensor is an analytical device, used for the detection of a chemical substance, that combines a biological component with a physicochemical detector.
Biosensors: are analytical tools for the analysis of bio-material samples to
gain an understanding of their bio-composition, structure and function by
converting a biological response into an electrical signal. The analytical
devices composed of a biological recognition element directly interfaced to a signal transducer which together relate the concentration of an analyte
Incineration is the method of choice for treating large volumes of infectious waste, animal carcasses, and contaminated bedding materials. Because incinerators usually are located some distance from the laboratory, additional precautions for handling and packaging of infectious waste are necessary.
Types of Biomedical Waste Disposal
Autoclaving. The process of autoclaving involves steam sterilization. ...
Incineration. The major benefits of incineration are that it is quick, easy, and simple. ...
Chemicals. When it comes to liquid waste, a common biomedical waste disposal method can be chemical disinfection. ...
Microwaving.
Prokaryotes are always unicellular, while eukaryotes are often multi-celled organisms. Additionally, eukaryotic cells are more than 100 to 10,000 times larger than prokaryotic cells and are much more complex. The DNA in eukaryotes is stored within the nucleus, while DNA is stored in the cytoplasm of prokaryotes
Difference between prokaryotic and eukaryotic cell.pptxAmjad Afridi
Eukaryotic cells have several other membrane-bound organelles not found in prokaryotic cells.
These include the mitochondria (convert food energy into adenosine triphosphate, or ATP, to power biochemical reactions); rough and smooth endoplasmic reticulum ,golgi complex and in the case of plant cells, chloroplasts
All of these organelles are located in the eukaryotic cell's cytoplasm.
Mycology is the branch of biology concerned with the study of fungi.
The word 'myco' is derived from the Greek word mýkēs meaning “mushroom, fungus”.
Heinrich Anton de Bary is the father of Mycology.
Fungi are eukaryotic organisms that include such as yeasts, moulds and mushrooms. These organisms are classified under kingdom fungi.
Fungi are diverse and widespread.
Fungi metabolism consists on a series of reactions (biochemical reactions) constantly occurring inside the cells to keep it alive and active and in the results biosynthesis of a huge number of compounds.
These compounds area usually divided into primary and secondary metabolites.
Primary metabolism is common to several species and usually produces compounds with the function of assuring fungi growth and development.
Primary metabolites are involved in the growth, development, and reproduction of organisms.
The primary metabolites consist of vitamins, amino acids, nucleosides and organic acids
Staphylococcus aureus is a bacterium that causes staphylococcal food poisoning, a form of gastroenteritis with rapid onset of symptoms. S. aureus is commonly found in the environment (soil, water and air) and is also found in the nose and on the skin of humans.
Communicable diseases are illnesses that spread from one person to another or from an animal to a person, or from a surface or a food. Diseases can be transmitted during air travel through: direct contact with a sick person. respiratory droplet spread from a sick person sneezing or coughing.
Host-Parasite relationship is the extreme case of animal association, in which both partners influence each others life by affecting each others metabolism and behaviour using different adaptive mechanisms in order to ensure their survival.
Bacteria have their own enzymes for
1. Cell wall formation
2. Protein synthesis
3. DNA replication
4. RNA synthesis
5. Synthesis of essential metabolites
Infections spread from animals to human are called zoonotic infections.
The term zoonos is’ Derived from the Greek
ZOON (animals) and NOSES (diseases)
Pathogens shared with wild or domestic animals cause more than 60% of infectious diseases in man.
Ozone (O3) is a molecule made up of three atoms of oxygen (O), and very reactive gas.
Bluish gas that harmful to breathe.
Is mostly found in the stratosphere, where it protects us from the Sun’s harmful ultraviolet (UV) radiation.
Although it represents only a tiny fraction of the atmosphere, ozone is essential for life on Earth.
Ozone in the stratosphere— a layer of the atmosphere between 15 and 50 kilometers (10 and 31 miles) above us—acts as a shield to protect Earth’s surface from the sun’s harmful ultraviolet radiation.
H: Infects only Human beings
I: Immunodeficiency Virus weakness the Immune system and increases the risk of infections
V: Virus that attacks the body and finally kills the body’s immune system
Tuberculosis is a communicable chronic granulomatous disease caused by Mycobacterium tuberculosis , where the center of the granuloma is Caseous necrosis
It usually involves the lungs but may affect any organ or tissue in the body
Airborne spread of droplet nuclei
Neuro-symbolic is not enough, we need neuro-*semantic*Frank van Harmelen
Neuro-symbolic (NeSy) AI is on the rise. However, simply machine learning on just any symbolic structure is not sufficient to really harvest the gains of NeSy. These will only be gained when the symbolic structures have an actual semantics. I give an operational definition of semantics as “predictable inference”.
All of this illustrated with link prediction over knowledge graphs, but the argument is general.
Dev Dives: Train smarter, not harder – active learning and UiPath LLMs for do...UiPathCommunity
💥 Speed, accuracy, and scaling – discover the superpowers of GenAI in action with UiPath Document Understanding and Communications Mining™:
See how to accelerate model training and optimize model performance with active learning
Learn about the latest enhancements to out-of-the-box document processing – with little to no training required
Get an exclusive demo of the new family of UiPath LLMs – GenAI models specialized for processing different types of documents and messages
This is a hands-on session specifically designed for automation developers and AI enthusiasts seeking to enhance their knowledge in leveraging the latest intelligent document processing capabilities offered by UiPath.
Speakers:
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👩🏫 Lenka Dulovicova, Product Program Manager, UiPath
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Clients don’t know what they don’t know. What web solutions are right for them? How does WordPress come into the picture? How do you make sure you understand scope and timeline? What do you do if sometime changes?
All these questions and more will be explored as we talk about matching clients’ needs with what your agency offers without pulling teeth or pulling your hair out. Practical tips, and strategies for successful relationship building that leads to closing the deal.
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
- Visualization tools to display your network;
- Grid simulation tools, such as power flows, security analyses (with or without remedial actions) and sensitivity analyses;
The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
JMeter webinar - integration with InfluxDB and GrafanaRTTS
Watch this recorded webinar about real-time monitoring of application performance. See how to integrate Apache JMeter, the open-source leader in performance testing, with InfluxDB, the open-source time-series database, and Grafana, the open-source analytics and visualization application.
In this webinar, we will review the benefits of leveraging InfluxDB and Grafana when executing load tests and demonstrate how these tools are used to visualize performance metrics.
Length: 30 minutes
Session Overview
-------------------------------------------
During this webinar, we will cover the following topics while demonstrating the integrations of JMeter, InfluxDB and Grafana:
- What out-of-the-box solutions are available for real-time monitoring JMeter tests?
- What are the benefits of integrating InfluxDB and Grafana into the load testing stack?
- Which features are provided by Grafana?
- Demonstration of InfluxDB and Grafana using a practice web application
To view the webinar recording, go to:
https://www.rttsweb.com/jmeter-integration-webinar
"Impact of front-end architecture on development cost", Viktor TurskyiFwdays
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GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
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The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
Builder.ai Founder Sachin Dev Duggal's Strategic Approach to Create an Innova...Ramesh Iyer
In today's fast-changing business world, Companies that adapt and embrace new ideas often need help to keep up with the competition. However, fostering a culture of innovation takes much work. It takes vision, leadership and willingness to take risks in the right proportion. Sachin Dev Duggal, co-founder of Builder.ai, has perfected the art of this balance, creating a company culture where creativity and growth are nurtured at each stage.
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A presentation about the usage and availability of Varnish on Kubernetes. This talk explores the capabilities of Varnish caching and shows how to use the Varnish Helm chart to deploy it to Kubernetes.
This presentation was delivered at K8SUG Singapore. See https://feryn.eu/presentations/accelerate-your-kubernetes-clusters-with-varnish-caching-k8sug-singapore-28-2024 for more details.
Let's dive deeper into the world of ODC! Ricardo Alves (OutSystems) will join us to tell all about the new Data Fabric. After that, Sezen de Bruijn (OutSystems) will get into the details on how to best design a sturdy architecture within ODC.
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The publishing industry has been selling digital audiobooks and ebooks for over a decade and has found its groove. What’s changed? What has stayed the same? Where do we go from here? Join a group of leading sales peers from across the industry for a conversation about the lessons learned since the popularization of digital books, best practices, digital book supply chain management, and more.
Link to video recording: https://bnctechforum.ca/sessions/selling-digital-books-in-2024-insights-from-industry-leaders/
Presented by BookNet Canada on May 28, 2024, with support from the Department of Canadian Heritage.
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The IoT and OT threat landscape report has been prepared by the Threat Research Team at Sectrio using data from Sectrio, cyber threat intelligence farming facilities spread across over 85 cities around the world. In addition, Sectrio also runs AI-based advanced threat and payload engagement facilities that serve as sinks to attract and engage sophisticated threat actors, and newer malware including new variants and latent threats that are at an earlier stage of development.
The latest edition of the OT/ICS and IoT security Threat Landscape Report 2024 also covers:
State of global ICS asset and network exposure
Sectoral targets and attacks as well as the cost of ransom
Global APT activity, AI usage, actor and tactic profiles, and implications
Rise in volumes of AI-powered cyberattacks
Major cyber events in 2024
Malware and malicious payload trends
Cyberattack types and targets
Vulnerability exploit attempts on CVEs
Attacks on counties – USA
Expansion of bot farms – how, where, and why
In-depth analysis of the cyber threat landscape across North America, South America, Europe, APAC, and the Middle East
Why are attacks on smart factories rising?
Cyber risk predictions
Axis of attacks – Europe
Systemic attacks in the Middle East
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https://sectrio.com/resources/ot-threat-landscape-reports/sectrio-releases-ot-ics-and-iot-security-threat-landscape-report-2024/
UiPath Test Automation using UiPath Test Suite series, part 4DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 4. In this session, we will cover Test Manager overview along with SAP heatmap.
The UiPath Test Manager overview with SAP heatmap webinar offers a concise yet comprehensive exploration of the role of a Test Manager within SAP environments, coupled with the utilization of heatmaps for effective testing strategies.
Participants will gain insights into the responsibilities, challenges, and best practices associated with test management in SAP projects. Additionally, the webinar delves into the significance of heatmaps as a visual aid for identifying testing priorities, areas of risk, and resource allocation within SAP landscapes. Through this session, attendees can expect to enhance their understanding of test management principles while learning practical approaches to optimize testing processes in SAP environments using heatmap visualization techniques
What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
Topics covered:
Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
UiPath Test Automation using UiPath Test Suite series, part 4
Introduction to biosensors
1. Essays in Biochemistry (2016) 60 1–8
DOI: 10.1042/EBC20150001
Version of Record published
30 June 2016
Introduction to biosensors
Nikhil Bhalla, Pawan Jolly, Nello Formisano and Pedro Estrela
Department of Electronic and Electrical Engineering, University of Bath, Bath BA2 7AY, U.K.
Correspondence: Pedro Estrela (p.estrela@bath.ac.uk)
Biosensors are nowadays ubiquitous in biomedical diagnosis as well as a wide range of
other areas such as point-of-care monitoring of treatment and disease progression, envi-
ronmental monitoring, food control, drug discovery, forensics and biomedical research. A
wide range of techniques can be used for the development of biosensors. Their coupling
with high-affinity biomolecules allows the sensitive and selective detection of a range of
analytes. We give a general introduction to biosensors and biosensing technologies, in-
cluding a brief historical overview, introducing key developments in the field and illustrat-
ing the breadth of biomolecular sensing strategies and the expansion of nanotechnological
approaches that are now available.
Introduction
A biosensor is a device that measures biological or chemical reactions by generating signals proportional
to the concentration of an analyte in the reaction. Biosensors are employed in applications such as disease
monitoring, drug discovery, and detection of pollutants, disease-causing micro-organisms and markers
that are indicators of a disease in bodily fluids (blood, urine, saliva, sweat). A typical biosensor is repre-
sented in Figure 1; it consists of the following components.
• Analyte: A substance of interest that needs detection. For instance, glucose is an ‘analyte’ in a biosen-
sor designed to detect glucose.
• Bioreceptor: A molecule that specifically recognises the analyte is known as a bioreceptor. Enzymes,
cells, aptamers, deoxyribonucleic acid (DNA) and antibodies are some examples of bioreceptors. The
process of signal generation (in the form of light, heat, pH, charge or mass change, etc.) upon inter-
action of the bioreceptor with the analyte is termed bio-recognition.
• Transducer: The transducer is an element that converts one form of energy into another. In a biosen-
sor the role of the transducer is to convert the bio-recognition event into a measurable signal. This
process of energy conversion is known as signalisation. Most transducers produce either optical or
electrical signals that are usually proportional to the amount of analyte–bioreceptor interactions.
• Electronics: This is the part of a biosensor that processes the transduced signal and prepares it for
display. It consists of complex electronic circuitry that performs signal conditioning such as amplifi-
cation and conversion of signals from analogue into the digital form. The processed signals are then
quantified by the display unit of the biosensor.
• Display: The display consists of a user interpretation system such as the liquid crystal display of a
computer or a direct printer that generates numbers or curves understandable by the user. This part
often consists of a combination of hardware and software that generates results of the biosensor in a
user-friendly manner. The output signal on the display can be numeric, graphic, tabular or an image,
depending on the requirements of the end user.
c
2016 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society. 1
2. Essays in Biochemistry (2016) 60 1–8
DOI: 10.1042/EBC20150001
Figure 1. Schematic representation of a biosensor
Historical background
The history of biosensors dates back to as early as 1906 when M. Cremer [1] demonstrated that the concentration of an
acid in a liquid is proportional to the electric potential that arises between parts of the fluid located on opposite sides of
a glass membrane. However, it was only in 1909 that the concept of pH (hydrogen ion concentration) was introduced
by Søren Peder Lauritz Sørensen and an electrode for pH measurements was realised in the year 1922 by W.S. Hughes
[2]. Between 1909 and 1922, Griffin and Nelson [3,4] first demonstrated immobilisation of the enzyme invertase
on aluminium hydroxide and charcoal. The first ‘true’ biosensor was developed by Leland C. Clark, Jr in 1956 for
oxygen detection. He is known as the ‘father of biosensors’ and his invention of the oxygen electrode bears his name:
‘Clark electrode’ [5]. The demonstration of an amperometric enzyme electrode for the detection of glucose by Leland
Clark in 1962 was followed by the discovery of the first potentiometric biosensor to detect urea in 1969 by Guilbault
and Montalvo, Jr [6]. Eventually in 1975 the first commercial biosensor was developed by Yellow Spring Instruments
(YSI). Table 1 shows the historical overview of biosensors in the period 1970–1992. Ever since the development of the
i-STAT sensor, remarkable progress has been achieved in the field of biosensors. The field is now a multidisciplinary
area of research that bridges the principles of basic sciences (physics, chemistry and biology) with fundamentals of
micro/nano-technology, electronics and applicatory medicine. The database ‘Web of Science’ has indexed over 84000
reports on the topic of ‘biosensors’ from 2005 to 2015.
Characteristics of a biosensor
There are certain static and dynamic attributes that every biosensor possesses. The optimisation of these properties
is reflected on the performance of the biosensor.
2 c
2016 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.
3. Essays in Biochemistry (2016) 60 1–8
DOI: 10.1042/EBC20150001
Table 1. Important cornerstones in the development of biosensors during the period 1970–1992
1970 Discovery of ion-sensitive field-effect transistor (ISFET) by Bergveld [7]
1975 Fibre-optic biosensor for carbon dioxide and oxygen detection by Lubbers and Opitz [8]
1975 First commercial biosensor for glucose detection by YSI [9]
1975 First microbe-based immunosensor by Suzuki et al. [10]
1982 Fibre-optic biosensor for glucose detection by Schultz [11]
1983 Surface plasmon resonance (SPR) immunosensor by Liedberg et al. [12]
1984 First mediated amperometric biosensor: ferrocene used with glucose oxidase for glucose detection [13]
1990 SPR-based biosensor by Pharmacia Biacore [8]
1992 Handheld blood biosensor by i-STAT [8]
Selectivity
Selectivity is perhaps the most important feature of a biosensor. Selectivity is the ability of a bioreceptor to detect a
specific analyte in a sample containing other admixtures and contaminants. The best example of selectivity is depicted
by the interaction of an antigen with the antibody. Classically, antibodies act as bioreceptors and are immobilised on
the surface of the transducer. A solution (usually a buffer containing salts) containing the antigen is then exposed
to the transducer where antibodies interact only with the antigens. To construct a biosensor, selectivity is the main
consideration when choosing bioreceptors.
Reproducibility
Reproducibility is the ability of the biosensor to generate identical responses for a duplicated experimental set-up.
The reproducibility is characterised by the precision and accuracy of the transducer and electronics in a biosensor.
Precision is the ability of the sensor to provide alike results every time a sample is measured and accuracy indicates
the sensor’s capacity to provide a mean value close to the true value when a sample is measured more than once.
Reproducible signals provide high reliability and robustness to the inference made on the response of a biosensor.
Stability
Stability is the degree of susceptibility to ambient disturbances in and around the biosensing system. These distur-
bances can cause a drift in the output signals of a biosensor under measurement. This can cause an error in the meas-
ured concentration and can affect the precision and accuracy of the biosensor. Stability is the most crucial feature in
applications where a biosensor requires long incubation steps or continuous monitoring. The response of transducers
and electronics can be temperature-sensitive, which may influence the stability of a biosensor. Therefore, appropriate
tuning of electronics is required to ensure a stable response of the sensor. Another factor that can influence the sta-
bility is the affinity of the bioreceptor, which is the degree to which the analyte binds to the bioreceptor. Bioreceptors
with high affinities encourage either strong electrostatic bonding or covalent linkage of the analyte that fortifies the
stability of a biosensor. Another factor that affects the stability of a measurement is the degradation of the bioreceptor
over a period of time.
Sensitivity
The minimum amount of analyte that can be detected by a biosensor defines its limit of detection (LOD) or sensi-
tivity. In a number of medical and environmental monitoring applications, a biosensor is required to detect analyte
concentration of as low as ng/ml or even fg/ml to confirm the presence of traces of analytes in a sample. For instance, a
prostate-specific antigen (PSA) concentration of 4 ng/ml in blood is associated with prostate cancer for which doctors
suggest biopsy tests. Hence, sensitivity is considered to be an important property of a biosensor.
Linearity
Linearity is the attribute that shows the accuracy of the measured response (for a set of measurements with different
concentrations of analyte) to a straight line, mathematically represented as y = mc, where c is the concentration of
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the analyte, y is the output signal, and m is the sensitivity of the biosensor. Linearity of the biosensor can be associated
with the resolution of the biosensor and range of analyte concentrations under test. The resolution of the biosensor
is defined as the smallest change in the concentration of an analyte that is required to bring a change in the response
of the biosensor. Depending on the application, a good resolution is required as most biosensor applications require
not only analyte detection but also measurement of concentrations of analyte over a wide working range. Another
term associated with linearity is linear range, which is defined as the range of analyte concentrations for which the
biosensor response changes linearly with the concentration.
Applications of biosensors
Biosensors have a very wide range of applications that aim to improve the quality of life. This range covers their use for
environmental monitoring, disease detection, food safety, defence, drug discovery and many more. One of the main
applications of biosensors is the detection of biomolecules that are either indicators of a disease or targets of a drug.
For example, electrochemical biosensing techniques can be used as clinical tools to detect protein cancer biomarkers
[14–16]. Biosensors can also be used as platforms for monitoring food traceability, quality, safety and nutritional
value [17,18]. These applications fall into the category of ‘single shot’ analysis tools, i.e. where cost-effective and
disposable sensing platforms are required for the application. On the other hand, an application such as pollution
monitoring [18,19] requires a biosensor to function from a few hours to several days. Such biosensors can be termed
‘long-term monitoring’ analysis tools. Whether it is long-term monitoring or single shot analysis, biosensors find
their use as technologically advanced devices both in resource-limited settings and sophisticated medical set-ups: e.g.
with applications in drug discovery [20–22]; for the detection of a number of chemical and biological agents that are
considered to be toxic materials of defence interest [23]; for use in artificial implantable devices such as pacemakers
[24] and other prosthetic devices [25]; and sewage epidemiology [26]. A range of electrochemical, optical and acoustic
sensing techniques have been utilised, along with their integration into analytical devices for various applications.
Figure 2 indicates different areas of research where biosensors have been used.
Nanotechnology
Irrespective of the field, miniaturisation has always proved to be beneficial for varied reasons. For instance, reducing
the size of the biosensor to the micro- or nano-scale can result in a better signal-to-noise ratio as well as the possibility
of using smaller sample volumes, which means lower assay costs. Moreover, when going towards nanoscale dimen-
sions, the surface-to-volume ratio of the sensing active area increases and the sizes of the detecting electrode and
that of the target biomarker become comparable. This causes both reduced non-specific binding and increased bind-
ing efficiency towards the target molecule. As a result, the bioreceptor becomes an active transducer for the sensing
system and it becomes possible to perform single-molecule detection [27].
An interesting fact in an electrochemical system is that towards nanoscale dimensions the double layer capaci-
tance dramatically decreases because of its dependence on the electrode area. As a result, the extremely low RsCdl
time constant (where Rs is the solution resistance, and Cdl is the double layer capacitance) allows ultra-fast electron-
transfer kinetics and short-life intermediate species can also be investigated. As the time constant decreases, the time
required to accomplish a measurement also diminishes towards the nanosecond domain. Moreover, when Cdl de-
creases dramatically, a further interesting consequence is the possibility of performing measurements in media with
a high solution resistance where normal macroelectrodes are not usable. In fact, by keeping the RsCdl factor constant,
it is possible to perform measurements even without the need of a supporting electrolyte [28].
In terms of nanomaterials, the discovery of graphene and its oxidised form, graphene oxide, opened new frontiers
in biosensors as well as in other research areas. Graphene is a pure form of carbon organised into single atom-thick
sheets. This feature gives graphene exceptional chemical and physical properties.
The integration of graphene, graphene oxide and carbon nanotubes (single or multiple one atom-thick carbon
concentric tubes) as well as nanoparticles and nanowires of different materials are widely reported in the literature for
electrode fabrication. Biosensors so fabricated can nowadays allow limits of detection lower than previously possible,
enabling even single-molecule detection.
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Figure 2. Major areas of applications for biosensors
Impact of biosensors
Looking at the never-ending literature related to biosensors over the last few decades, it undoubtedly reveals that
biosensors are attractive not only in academia but also in industry. Biosensor technology exploits the unique prop-
erties of a biological recognition event on a transducing device. In such an event, the interaction of the analyte with
the bioreceptor is converted into a suitable output that is easily readable by the user. This approach not only exploits
the molecular binding event, but also brings researchers from different areas of science and engineering to bridge
their skills. Similar practices have created an immense impact on early-stage researchers in the field of biosensors.
In addition it has opened new frontiers in scientific research where considerable attention has been drawn towards
the development of technologies to benefit different areas including healthcare. Working in an interdisciplinary field
helps to think out of the box and work together with distinct professionals where every idea contributes to make
something substantial. A simple example is a pregnancy test biosensor where researchers from biology highlighted
the biological aspects and co-operated with engineers to work on the electronics of the system for the read-out. Finally,
research from the laboratory is being transferred to customers worldwide because of management professionals. It
would be naı̈ve to think that biosensor research is confined to a niche – this can be seen clearly by the rapid increase in
biosensors available in the market in recent times. Recently, there has been a gradual increase in start-up companies
based on biosensor technology worldwide, which is having a profound impact on the healthcare industrial sector. In
general, it can be said that biosensors have found an important place in our society as they aim to improve the quality
of life in diverse areas such as homeland defence and security, agriculture, food safety, environment, medicine and
pharmacology.
Challenges in biosensing research
Biosensors have been under development for around 50 years and the research in this field has made tremendous
contributions in academia over the last 10 years. However, besides lateral flow pregnancy tests and electrochemical
glucose biosensors, very few biosensors have achieved global commercial success at the retail level. There are sev-
eral factors for this: difficulties in translating academic research into commercially viable prototypes by industry;
complex regulatory issues in clinical applications; and it has not always been trivial to either find researchers with
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a background in biosensor technology or engage researchers from different disciplines of science and engineering
to work together. Another reason is that academic research is driven by propositions of peer review of science, and
funding agencies and politics that are sometimes characterised by various conflicts of interest. It is often a jury of
academics who determine the priorities of funding agencies with legislators who seek considerable warrants for the
funding they approve. If a subject can be made to appear fancy and attractive, it has a better chance of success. In this
aspect, biosensor technology has a certain distinction that has been proficiently sold as a priority. Biosensors should
be aimed as practical devices to be used. Although biosensors employ fundamental sciences, it can hardly be ratio-
nalised as ‘curiosity-driven’ research. On the other hand, research in industry obeys the trend of ‘follow the money’
to some extent. Given the success of commercial glucose sensors, biosensor research is, of course, very lucrative for
the industry’s long-term sustainability. However, it takes quite a long time to produce a commercially viable device
from a proof of concept demonstrated in academia. This also involves a number of risks that industries are reluctant
to face.
As a result there are unaddressed mandatory issues concerning the production of a commercial biosensor, such as:
• Identification of the market that is interested in a biosensor for a specific analyte of interest.
• Clear-cut advantages over existing methods for analyses of that analyte.
• Testing the performance of the biosensor both in use and after storage. Response of a biosensor after 6 months
of storage is the absolute minimum for any practical commercial application.
• Stability, costs and ease of manufacturing each component of the biosensor.
• Hazards and ethics associated with the use of the developed biosensor.
The good news about biosensing technologies is that most of the barriers outlined above are being broken rapidly.
High levels of investment have been poured into translational research worldwide, particularly, for healthcare appli-
cations. This is bringing industry closer to academia in order to provide commercially viable products. On the other
hand, there has been an outstanding improvement in the way scientists work across boundaries. Engineering and
physical scientists nowadays have a much better understanding of basic biomolecular processes, while biochemists
and molecular biologists have greater awareness of the capabilities of different technologies. The alliance of experts
of different disciplines from the onset of biosensing development projects is a very attractive proposition that will
certainly bring advanced and novel products to the market.
Conclusions
In vitro molecular biosensors are nowadays ubiquitous in biomedical diagnosis as well as a wide range of other
areas such as point-of-care monitoring of treatment and disease progression, environmental monitoring, food con-
trol, drug discovery, forensics and biomedical research. Biosensor devices require the interaction of different disci-
plines and rely on very distinct aspects such as the study of interactions of bio-recognition elements with biomolecular
analytes, immobilisation of biomolecules on to solid surfaces, development of anti-fouling surface chemistries, de-
vice design and fabrication, integration of biology with the devices, microfluidics, on-chip electronics, packaging,
sampling techniques, etc.
The rapid development in the field of biosensors over the past decades, both at the research and product devel-
opment level, is due mainly to: (i) developments in miniaturisation and microfabrication technologies; (ii) the use
of novel bio-recognition molecules; (iii) novel nanomaterials and nanostructured devices; and (iv) better interaction
between life scientists and engineering/physical scientists.
A range of target molecules and affinity reagents can be used for a wide range of biosensors. Antibody-based sys-
tems (Chapter 2) represent the gold standard in biosensors. Novel affinity reagents such as synthetic receptors are
currently making way to replace antibodies on biosensors, in particular, aptamers such as peptide aptamers (Chap-
ter 3) and oligonucleotide aptamers (Chapter 4). DNA and oligonucleotide analogues such as peptide nucleic acids
(PNAs) and locked nucleic acids (LNAs) are often used as probe molecules for DNA and microRNA (miRNA) sens-
ing (Chapter 4). Determination of protein glycosylation levels using lectins is currently of great interest in medical
diagnosis (Chapter 5) as is the sensing of toxins in environmental monitoring (Chapter 6). Suitable bioconjugation
strategies and stabilisation of biomolecules on electrodes is essential for the development of commercially viable
biosensors (Chapter 7).
A range of transduction techniques can be used in biosensing devices, including electrochemical sensors (Chap-
ter 8), field-effect transistors (Chapter 9), optical sensors (Chapter 10) and acoustic-sensitive sensors (Chapter 11).
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Lateral flow systems (Chapter 12) have great promise for the development of inexpensive and easy to use point-of-
care sensors beyond the traditional pregnancy tests, whereas lab-on-chip devices (Chapter 13) integrate different
microfabrication techniques enabling biosensors to be employed in a wide range of applications using minute sample
volumes and minimum sample preparation.
Summary
• Biosensors are nowadays ubiquitous in different areas of healthcare.
• Pregnancy tests and glucose monitoring sensors are the two main examples of very successful biosensor
devices.
• A range of transduction techniques such as electrochemical, optical and acoustic, can be used for biosensors.
• High-affinity reagents such as antibodies, enzymes and synthetic biomolecules can be coupled to the trans-
ducer in order to provide specificity of the biosensors.
• Nanotechnology has had a major impact on recent advances of biosensing technology.
Funding
We acknowledge funding from the European Commission Framework Programme through the Marie Curie Initial Training Network
PROSENSE [grant number 317420, 2012–2016].
Competing Interests
The Authors declare that there are no competing interests associated with the manuscript.
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