This document discusses the development of a biosensor for cholesterol detection. It begins by noting the health impacts of cardiovascular disease and defining hypercholesterolemia. It then reviews conventional cholesterol testing methods and their drawbacks before introducing the potential for biosensors. The document outlines different types of biosensors classified by transducer and describes examples of electrochemical and optical biosensors for cholesterol. It also discusses invasive versus non-invasive biosensor designs and the potential use of saliva for non-invasive cholesterol detection.

1. BIOSENSOR FOR
CHOLESTEROL DETECTION
By- Yashi Jain

2. INTRODUCTION
According, to WHO reports every year 17.9 million people die because of
cardiovascular diseases (CVDs).
This elevated condition of cholesterol in blood is known as Hypercholesterolemia.
Cholesterol is a sterol and it serves as a precursor for the biosynthesis of steroid
hormones, bile acid and vitamin D.
Cholesterol in blood is carried by lipoprotein molecules (lipid+protein).
Use of biosensors are in various fields, one of such is in medical field.
Estimation of cholesterol level in blood is the most important and challenging task
for medical industry.

3. CONVENTIONAL METHODS TO
DETERMINE CHOLESTEROL
Lieberman
Burchard Test
High
Performance liquid
Chromatography(H
PLC)
Zaks Method
Cholesterol
oxidase
peroxidase
method

4. NORMAL RANGE OF CHOLESTEROL
IN BLOOD
HDL Level
Men-30-60 mg/dl
Women: 40-70 mg/dl
LDL Level
80-130 mg/dl
TG Level
50-200 mg/ dl

5. DRAWBACK OF CONVENTIONAL
METHODS
Time consuming
Labour intensive
Less specific
Less sensitive
Interference of several substances with the colour reaction in colorimetric
method may take place

6. WORKING OF BIOSENSOR
Batra et al., 2019

7. BASED ON TRANSDUCER BIOSENSORS
ARE CLASSIFIED AS
Potentiometric Amperometric
Cyclic
Voltammetry
Fluorescence Absorption ReflectionOptical
Electrochemi
cal

8. ELECTROCHEMICAL BASED
CHOLESTEROL BIOSENSOR
These are enzymatic catalysis of a reaction that produces or
consumes electrons and generates signal, which are captured by
transducer.
Signal is ∝ to concentration of the substance.
The colour of the sample will not interfere with the redox reaction in
electrochemical method and hence do not cause any change in the
electrical signal.
In it no specific reagent is required.
It’s response time and sensitivity is very high.

9. OPTICAL BASED BIOSENSORS
Optical based biosensor detects in the form of fluorescence,
absorbance, and luminescence.
These types of biosensor works on specific reagents like tris (4,7-
diphenyl-I,10-phenanthroline) ruthenium.
These are very sensitive.
The diffusion of analytes, may lead to low response time.

10. WORKING OF INVASIVE CHOLESTEROL
BIOSENSOR
In invasive biosensor, blood
sample is used for detection. In
it blood sample is placed on the
test strip which is inserted into
the biosensor. This strip later
detects level of cholesterol in
blood within a minute.

11. WORKING OF NON INVASIVE
CHOLESTEROL BIOSENSOR
A drop of digitonin is used which binds selectively to the cholesterol
in the skin.
This liquid contains an enzyme linked to the digitonin by a
copolymer.
After incubation period, the area is blotted dry to remove any
unbound digitonin solution.
A second drop of liquid is then added, containing a substrate for the
horseradish peroxidase enzyme.
•When combined, a blue color change occurs indirect proportion to
the amount of digitonin that is bound to skin cholesterol. After
minutes, a hand-held spectrophotometer is placed over the drop to
measure the precise blue color, which indicates the skin cholesterol

12. USE OF SALIVA FOR CHOLESTEROL
DETECTION
Lee et al., 2019

13. DIFFERENCE BETWEEN INVASIVE
AND NON INVASIVE BIOSENSORS

14. REFERENCES
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