Novel effects can occur in materials when structures are formed with sizes comparable to any one of many possible length scales, such as the de Broglie wavelength of electrons, or the optical wavelengths of high energy photons. In these cases quantum mechanical effects can dominate material properties. One example is quantum confinement where the electronic properties of solids are altered with great reductions in particle size. The optical properties of nanoparticles, e.g. fluorescence, also become a function of the particle diameter. This effect does not come into play by going from macrosocopic to micrometer dimensions, but becomes pronounced when the nanometer scale is reached.
Novel effects can occur in materials when structures are formed with sizes comparable to any one of many possible length scales, such as the de Broglie wavelength of electrons, or the optical wavelengths of high energy photons. In these cases quantum mechanical effects can dominate material properties. One example is quantum confinement where the electronic properties of solids are altered with great reductions in particle size. The optical properties of nanoparticles, e.g. fluorescence, also become a function of the particle diameter. This effect does not come into play by going from macrosocopic to micrometer dimensions, but becomes pronounced when the nanometer scale is reached.
A convenient method of synthesizing Silver Nanoparticles form Bonatea steudneri leave extract and evaluation of their electrocatalytic and phenol removal properties.
This includes what is Quantum Dots and their properties ,types of synthesis methods of nano materials such as top down, bottom up etc.It includes few things about Carbon Quantum Dots.
A convenient method of synthesizing Silver Nanoparticles form Bonatea steudneri leave extract and evaluation of their electrocatalytic and phenol removal properties.
This includes what is Quantum Dots and their properties ,types of synthesis methods of nano materials such as top down, bottom up etc.It includes few things about Carbon Quantum Dots.
know more about nanomaterials and its apllication in future as well as current situation, and what wil we reserch on basis of nanomaterials and carbon structure and its aplication in such futuriastic manner.
Dr. Charles Lee presents an overview of his program, Organic Materials Chemistry, at the AFOSR 2013 Spring Review. At this review, Program Officers from AFOSR Technical Divisions will present briefings that highlight basic research programs beneficial to the Air Force.
The IOSR Journal of Pharmacy (IOSRPHR) is an open access online & offline peer reviewed international journal, which publishes innovative research papers, reviews, mini-reviews, short communications and notes dealing with Pharmaceutical Sciences( Pharmaceutical Technology, Pharmaceutics, Biopharmaceutics, Pharmacokinetics, Pharmaceutical/Medicinal Chemistry, Computational Chemistry and Molecular Drug Design, Pharmacognosy & Phytochemistry, Pharmacology, Pharmaceutical Analysis, Pharmacy Practice, Clinical and Hospital Pharmacy, Cell Biology, Genomics and Proteomics, Pharmacogenomics, Bioinformatics and Biotechnology of Pharmaceutical Interest........more details on Aim & Scope).
All manuscripts are subject to rapid peer review. Those of high quality (not previously published and not under consideration for publication in another journal) will be published without delay.
Introduction to nanoparticles and bionanomaterialsShreyaBhatt23
what is a nanoparticle, why small is good,nanoscale effect, how to make nanostructures,top down and bottom up approachs,
methods of making nanomaterials,chemical methods od making nanomaterial,bionanomaterials,
Quantum dots were discovered in solids (glass crystals) in 1980 by Russian physicist Alexei Ekimov while working at the Vavilov State Optical Institute. In late 1982, American chemist Louis E. Brus, then working at Bell Laboratories (and now a professor at Columbia University), discovered the same phenomenon in colloidal solutions (where small particles of one substance are dispersed throughout another; milk is a familiar example). These two scientists shared the Optical Society of America's 2006 R.W. Wood Prize for their pioneering work.
Abstract
In the last decade, developments in nanotechnology have provided a new field in medicine called “Nanomedicine”. Nanomedicine has provided new tools for photodynamic therapy. Quantum dots (QDs) are approximately spherical nanoparticles that have attracted broad attention and have been used in nanomedicine applications. QDs have high molar extinction coefficients and photoluminescence quantum yield, narrow emission spectra, broad absorption, large effective stokes shifts. QDs are more photostable and resistant to metabolic degradation. These photosensitizing properties can be used as photosensitizers for Photodynamic Therapy (PDT). PDT has been recommended for its unique characteristic, such as low side effect and more efficiency. Therefore, nanomedicine leads a promising future for targeted therapy in cancer tumor. Furthermore, QDs have recently been applied in PDT, which will be addressed in this review letter. Also this review letter evaluates key aspects of nano-particulate design and engineering, including the advantage of the nanometer scale size range, biological behavior, and safety profile.
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
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.
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
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
Slack (or Teams) Automation for Bonterra Impact Management (fka Social Soluti...Jeffrey Haguewood
Sidekick Solutions uses Bonterra Impact Management (fka Social Solutions Apricot) and automation solutions to integrate data for business workflows.
We believe integration and automation are essential to user experience and the promise of efficient work through technology. Automation is the critical ingredient to realizing that full vision. We develop integration products and services for Bonterra Case Management software to support the deployment of automations for a variety of use cases.
This video focuses on the notifications, alerts, and approval requests using Slack for Bonterra Impact Management. The solutions covered in this webinar can also be deployed for Microsoft Teams.
Interested in deploying notification automations for Bonterra Impact Management? Contact us at sales@sidekicksolutionsllc.com to discuss next steps.
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.
Software Delivery At the Speed of AI: Inflectra Invests In AI-Powered QualityInflectra
In this insightful webinar, Inflectra explores how artificial intelligence (AI) is transforming software development and testing. Discover how AI-powered tools are revolutionizing every stage of the software development lifecycle (SDLC), from design and prototyping to testing, deployment, and monitoring.
Learn about:
• The Future of Testing: How AI is shifting testing towards verification, analysis, and higher-level skills, while reducing repetitive tasks.
• Test Automation: How AI-powered test case generation, optimization, and self-healing tests are making testing more efficient and effective.
• Visual Testing: Explore the emerging capabilities of AI in visual testing and how it's set to revolutionize UI verification.
• Inflectra's AI Solutions: See demonstrations of Inflectra's cutting-edge AI tools like the ChatGPT plugin and Azure Open AI platform, designed to streamline your testing process.
Whether you're a developer, tester, or QA professional, this webinar will give you valuable insights into how AI is shaping the future of software delivery.
Search and Society: Reimagining Information Access for Radical FuturesBhaskar Mitra
The field of Information retrieval (IR) is currently undergoing a transformative shift, at least partly due to the emerging applications of generative AI to information access. In this talk, we will deliberate on the sociotechnical implications of generative AI for information access. We will argue that there is both a critical necessity and an exciting opportunity for the IR community to re-center our research agendas on societal needs while dismantling the artificial separation between the work on fairness, accountability, transparency, and ethics in IR and the rest of IR research. Instead of adopting a reactionary strategy of trying to mitigate potential social harms from emerging technologies, the community should aim to proactively set the research agenda for the kinds of systems we should build inspired by diverse explicitly stated sociotechnical imaginaries. The sociotechnical imaginaries that underpin the design and development of information access technologies needs to be explicitly articulated, and we need to develop theories of change in context of these diverse perspectives. Our guiding future imaginaries must be informed by other academic fields, such as democratic theory and critical theory, and should be co-developed with social science scholars, legal scholars, civil rights and social justice activists, and artists, among others.
UiPath Test Automation using UiPath Test Suite series, part 3DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 3. In this session, we will cover desktop automation along with UI automation.
Topics covered:
UI automation Introduction,
UI automation Sample
Desktop automation flow
Pradeep Chinnala, Senior Consultant Automation Developer @WonderBotz and UiPath MVP
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Connector Corner: Automate dynamic content and events by pushing a buttonDianaGray10
Here is something new! In our next Connector Corner webinar, we will demonstrate how you can use a single workflow to:
Create a campaign using Mailchimp with merge tags/fields
Send an interactive Slack channel message (using buttons)
Have the message received by managers and peers along with a test email for review
But there’s more:
In a second workflow supporting the same use case, you’ll see:
Your campaign sent to target colleagues for approval
If the “Approve” button is clicked, a Jira/Zendesk ticket is created for the marketing design team
But—if the “Reject” button is pushed, colleagues will be alerted via Slack message
Join us to learn more about this new, human-in-the-loop capability, brought to you by Integration Service connectors.
And...
Speakers:
Akshay Agnihotri, Product Manager
Charlie Greenberg, Host
Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
Paper presented at SYNERGY workshop at AVI 2024, Genoa, Italy. 3rd June 2024
https://alandix.com/academic/papers/synergy2024-epistemic/
As machine learning integrates deeper into human-computer interactions, the concept of epistemic interaction emerges, aiming to refine these interactions to enhance system adaptability. This approach encourages minor, intentional adjustments in user behaviour to enrich the data available for system learning. This paper introduces epistemic interaction within the context of human-system communication, illustrating how deliberate interaction design can improve system understanding and adaptation. Through concrete examples, we demonstrate the potential of epistemic interaction to significantly advance human-computer interaction by leveraging intuitive human communication strategies to inform system design and functionality, offering a novel pathway for enriching user-system engagements.
De-mystifying Zero to One: Design Informed Techniques for Greenfield Innovati...
Optical Imaging Probe development
1. Probe developments;
Optical Imaging Probes
Dr. Chalermchai Pilapong
Center of Excellence for Molecular Imaging (CEMI), Chiang Mai University
1
SMITH 2013” 28 November 2013, Holiday Inn,
Chiang Mai, Thailand.
2. Outline
• General Aspects of Optical Imaging (OI) Probe
•
•
•
Organic molecule-based OI Probe
Metal complex-based OI Probe
Inorganic nanocrystal-based OI Probe
• Design Issues for probe development
2
3. What is OI Probe?
Optical imaging probes are agents used to visualize, characterize, and
measure biological processes in living systems via emitted light.
Live cell imaging
Cell tracking and
trafficking
In vivo imaging
3
4. Basic of Luminescence
Fluorescence is short-lived, with luminescence ceasing
almost immediately (<10-7 sec) ,while phosphorescence
features luminescence from 10-4 to several seconds.
4
5. Strategy For Wavelength
Selection
Optical imaging window
Visible
Near infrared
650 – 1000 nm
- minimal light absorption
by tissues and organisms
- Enhanced penetration of both
excitation and emission light
- Improved signal-to-noise ratio
5
6. Typical sources of OI Probe
Organic molecules (usually with conjugated pbonds) – synthetic fluorophores or dye (fluorescein,
rhodamine, …), biological molecules (aromatic
amino acids – Trp, Tyr, chlorophyll, …)
Metal complex molecules – transition metal
complex, heavy metal complexes, lanthanide and
actinide ), …
Inorganic nanocrystals – the spectra depend on
the bandgap size, which depends on the size of
the crystal e.g. Quantum dot, metal nanoclusters 6
7. Small organic molecules
- usually with conjugated π-bonds
- dominate the commercial market of imaging agents,
Abs. 673 nm
Em. 692 nm
Curr Org Synth. 2011, 8, 521–534
Abs. 747 nm
Em. 774 nm
Problems
Photobleaching
poor photochemical
stability
very short lifetime
7
8. Small organic molecules
Newly developed NIR dyes for cancer imaging
- Improved chemical and
photostability
- High fluorescence
intensity
- Long fluorescent life time
- Improved water-soluble
property
Biomaterials 32, 2011, 7127-7138
8
10. Small organic molecules
• Direct conjugation
a gastric tumor
angiogenesis marker
candidate
Bioconjugate Chem. 2013, 24, 1134−1143
10
11. Small organic molecules
• Dye-conjugated nanoparticles
Schematic of different dye labeled nanoparticles
Different organic dyes incorporated into silica nanoparticles11
Nano Lett., Vol. 5, No. 1, 2005
12. Small organic molecules
• Dye-conjugated nanoparticles
• Form stable colloidal solutions in a wide
• Show good image contrast (high signal-to-noise
variety of in vitro and in vivo environments
ratio)
• Possess chemical stability under a wide variety • Have sufficiently long circulation time in the
of physiological conditions (i.e. solvent polarity,
blood if administered intravenously
reducing environment,ionic strength or pH)
• Display high sensitivity and selectivity for the
• Exhibit limited nonspecific binding to avoid
target after ligand conjugation
Macrophagocytic system (MPS) uptake
• Have programmed clearance mechanisms
12
Chem. Soc. Rev., 2012, 41, 2673
15. Metal complexes
Based on phosphorescence not fluorescence
- large Stokes shift (the difference in wavelength
between the absorbed and emitted light)
- long lifetimes
- More resistant to Photodegradable and
photobleaching
Inorg. Chem. 49 (2010) 2530
15
17. Metal Complexes
• Targeted imaging with metal complexes
complexes can be modified
routinely through structural
changes of any or all of their
ligands in a stepwise and
potentially combinatorial
approach to synthesis.
17
18. Metal Complexes
• Targeted imaging with metal complexes
Structure of a biotinylated Rh complex
Inorg.Chem. 2010, 49, 4984.
Chem. Commun. 46 (2010) 6255
18
20. Metal Complexes
• Dye-incorporated SiNPs
Reverse microemulsion method via hydrolysis/condensation reaction
The methodological comparison between the post-loading route and in situ
co-loading route.
20
21. Luminescence Inorganic
nanocrystals
• Quantum dots
• Metal nanoclusters
• Rare earth nanophosphors
Why nanoparticles?
1) Drugs, contrast agents,
paramagnetic or
radiolabeled probes can
be vehiculated by NPs
2) NPs can be multifunctionalized to confer
differents features on them
21
22. Quantum Dots (QD)
Quantum dot; Highly fluorescent semiconductor nanocrystal with a size of ~ 1-10
nm. Its electronic and optical properties deviate substantially from those of the bulk
material and are strongly size-dependent
22
23. Quantum Dots (QD)
• Fluorescence emission occurs when an electron excited to the
conduction band returns to the valence band
• The energy of this transition varies with nanoparticle size
• Wavelength of emitted light is also, therefore, size dependent!
5.8 nm
1.2 nm
CdSe Quantum Dots
23
24. Quantum Dots (QD)
Organic fluorophore
i.e. fluorescein
-Absorption band narrow:
Limited choice on EX
Long EM tail
Quantum dot
-Broad abs :
Wide choice of EX
-EM narrow & symmetric
No EM tail
24
25. Quantum Dots (QD)
• Applications in biological labeling and Imaging
Live cell imaging
Cell tracking and
trafficking
In vivo imaging
QD has many important applications in biology, especially in cell imaging,
tracking and trafficking as well as in vivo imaging
Nat. Met. 2004, 1, 73
Nat. Comm. 2013, 4, 1619
25
26. Quantum Dots (QD)
• QDs versus conventional dyes
QD
Dye
Single QD’s appear 10-20 times brighter than
organic dyes
Dye QD
Nature Biotech., 2003, 21, 41
26
27. Quantum Dots (QD)
Novel Quantum Dot-Based Technique Sees 100 Different Molecules
in a Single Cell
a multicolour multicycle
in situ imaging technology
Nat. Comm. 2013, 4, 1619
27
28. Quantum Dots (QD)
A Novel Clinically Translatable Fluorescent Nanoparticle for Targeted
Molecular Imaging of Tumors in Living Subjects
InP/ZnS QD
Nano Lett. 2012, 12, 281−286
28
29. Quantum Dots (QD)
Synthesis (a) High temperature route e.g. Hot Injection
Technique
Usually requires inert gas (Ar, N2)
Precursor
Generally,
Organometallic cpd
S,Se or Te precursor dissolved in
high bp solvent/stabilizing
agent: TOPO, TOP, C11amine ~ 340 oC
Maintained temperature at ~300 oC for QD growth
J. Am. Chem. Soc., 2003, 125, 12567
29
30. Quantum Dots (QD)
Synthesis (b) Low temperature route
Usually requires inert gas (Ar, N2)
QD growth start by heating the solution to 95 oC
Grow for 20, 40 and 90 mins to make green, yellow and red CdTe QDs
Best quantum yield: ~ 45%
Adv. Mater., 2007, 19, 376.
30
31. Quantum Dots (QD)
Comparison of the two synthetic approaches
High Temperature Route
Highly crystalline QD
Mono-disperse, narrow size distribution
Easy core/shell growth control
High quantum yield, up to 90%
QD coated with hydrophobic ligand, insoluble
in water, post surface modification necessary
TEM image
Low Temperature Route
Water-soluble, no post synthesis surface modification
Not highly crystalline
Broader size distribution
Difficult to make core/shell QD
Low quantum yield: typically < 15% (with exceptional ~ 45%)
31
32. Quantum Dots (QD)
• Surface modification for QDs
Advantages:
Highly stable, biocompatible,
water soluble QD, high
fluorescence QY maintained
Drawbacks:
Big size, > 20 nm,
Expensive ligand
32
33. Quantum Dots (QD)
Advantages: small QD
size, easy to conduct,
cheap capping ligand
Drawbacks: Quantum yield
decrease, lack of long term
stability, pH-sensitive
33
35. Quantum Dots (QD)
• QD are a possible replacement for organic dyes
• Quantum Confined systems make scientist can
design the optical properties of the material
• QD have been covalently linked to biorecognition
molecules such as peptides, antibodies, nucleic
acids or small-molecule ligands
• QD have more surface area and functionalities
than conventional dyes; that can be used for
linking to multiple diagnostic and therapeutic
agents
35
37. Metal Nanoclusters (NCs)
Metals NCs e.g. Au nanoclusters (<2nm)
the new class of nanomaterials that plays
novel physical and chemical properties due
to a very small size of this material (< 2 nm)
A simple energy diagram of photoluminescence
in gold nanoclusters
J. Med Biol Eng., 2009, 29, 276
size-dependent fluorescence
emission, large Stock shift and high
photo-stability.
37
38. Metal Nanoclusters (NCs)
• NCs in bioimaging
Advantages over QD
- low toxicity,
- easy synthesis and
functionalization,
- good water solubility
Sci. Rep, 2013 ,3. 1157; Nanoscale, 2013,5, 1009-1017
Angew. Chem. Int. Ed. 2013, 52, 12572 –12576
38
39. Metal Nanoclusters (NCs)
• Synthesis
1) Using strong reductive agent e.g. NaBH4
-limits their applications in bioimaging and related fields
2) Biomolecular-assisted synthesis
- Most common route
- simple and environmental benign
39
40. Metal Nanoclusters (NCs)
Renal clearance and Tumor Targeting of Near-IR-Emitting PEG-AuNPs
Scheme of the particle synthesis
Renal clearance kinetics of the PEG-AuNPs
Angew. Chem. Int. Ed. 2013, 52, 12572 –12576
In vivo NIR fluorescence images
of the mouse iv injected with PEG-AuNPs
40
41. Metal Nanoclusters (NCs)
NIR fluorescent RNase-A-encapsulated gold nanocluster
is used for targeted cellular imaging with potential for oral route administration.
37 oC
water
Bright-field and the corresponding fluorescence
images of Caco-2 cells after treatment with the
RNase-A-AuNC (a, b) and VB12-R-AuNC (c,
d) for 12 h.
Nanoscale, 2013,5, 1009-1017
41
42. Rare earth nanophosphors
Inorganic NPs doped with trivalent lanthanide
ions (Ln3+)
Advantages
- narrow emission band widths
(<10 nm)
- large Stokes or anti-Stokes shift
(larger than 100–
200 nm)
- long luminescence lifetimes (ms–s
range),
42
44. Rare earth nanophosphors
One-Pot Syntheses and Cell Imaging
Applications of Poly(amino acid)
Coated LaVO4:Eu3+ Luminescent
Nanocrystals
44
45. Design Issues of OI Probes
(a) reporter units or payloads
Optical properties
should be improved
for In vivo applications
45
46. Design Issues of OI Probes
(b) Bifunctional chelator or coating reagent
An ideal ligand or chelator should be able to form a stable metal chelate with
high thermodynamic stability and kinetic inertness.
Silica coating
Polymer encapsulating
46
47. Design Issues of OI Probes
(c) Linkers; A group of compound used to link between reporter
unit and targeting molecules which can consist of pharmacokinetic
modifers, spacers, conjugation groups
-
Amine-to-Amine Crosslinkers
Amine-to-Sulfhydryl Crosslinkers
Carboxyl-to-Amine Crosslinkers
Photoreactive Crosslinkers
Sulfhydryl-to-Carbohydrate Crosslinkers
Sulfhydryl-to-Hydroxyl Crosslinkers
Sulfhydryl-to-Sulfhydryl Crosslinkers
Minimize nonspecific absorption
Retain specificity of
targeting molecules
47
48. Design Issues of OI Probes
(d) Targeting biomolecules
Identification of lead target candidates
•
•
•
•
•
•
•
•
Biomarker
discovery
Growth factors (e.g. VEGF, F6F, integrins)
Membrane receptors stimulated by growth factors
Intracellular targets (enzymes, steroid receptors)
Transporters of nutrients and pseudo-nutrients
Marker associated with change of the extracellular
Matrix (e.g. Metalloproteases)
Marker associated with the malign formation of the
Cell membrane matrix (e.g. prolin, Cholin)
Marker of apoptosis
Marker of vulnerable athorosclerosis plaques (e.g. integrins, LDL)
48
49. Design Issues of OI Probes
(d) Targeting biomolecules
Antibody
49
50. Design Issues of OI Probes
(d) Targeting biomolecules
Small molecules
50
51. Design Issues of OI Probes
(d) Targeting biomolecules
Aptamers are short DNA or RNA oligonucleotides artificially generated to bind
tightly and specifically to various targets including small molecules, protein, cell
and etc..
Advantages of aptamers over antibodies:
• Broader target choice;
• Higher ligand specificity with comparable affinity (nM to pM);
• Produced by chemical synthesis, avoiding using animals and so no batchto-batch variations;
• Manufacturing costs and time are all lower compared to that of monoclonal
antibody production.
• More resistant to thermal/chemical denaturation.
• Easy to label with reporters
Nature Rev. Microbiol., 2006, 4, 588
51
52. Design Issues of OI Probes
(d) Targeting biomolecules
Aptamers
52
53. Design Issues of OI Probes
(d) Targeting biomolecules
Aptamers
53
54. Summary
Criteria for a useful fluorophore for imaging
- able to enter cells;
- localise in desired compartments;
- be biocompatible.e.g. non-toxic and stable/soluble in biological media;
- be excited and emit at non-damaging wavelengths (visible/ NIR);
- show a Stokes shift, or fluorescence lifetime which allows differentiation from
autofluorescence;
- be resistant to photobleaching (photochemical destruction of the agent).
Design consideration for Probe development
- Sensitivity
- Stability
- Signal-to-noise ratio (SNR)/target-to-nontarget ratio
- Bioavailability
- Biocompatibility
- Pharmacokinetics
54