NANOBIOSENSORSBiosensors on the nano-scale size

NanobiosensorA device incorporating a biological sensing element either intimately connected to or integrated within a transducer and a nanobiosensoris a biosensor that on the nano-scale size

• Recognition based on affinity between complementary structures like:

enzyme-substrate, antibody-antigen , receptor-hormone complex.

Selectivity and specificity depend on biological recognition systems connected to a suitable transducer.

History• The concept of biosensor was come up by Professor Leland

C Clark in 1956, who was identified as the father of the biosensor concept.

• Oxygen electrode for measure the concentration of oxygen in a any liquid

• 1962-the idea of oxygen electrode Clark came to reality

History ……….• 1975- idea of utilizing bacteria as the biological element in

microbial electrodes for the measurement of alcohol• 1975-first commercial biosensor (Yellow Spring

Instrumental Biosensor)• 1975-first microbe based biosensor (first Immunosensor)• 1983-first surface plasmonresonance (SPR) immunosensor• 1987-Blood Glucose biosensor launchedby Medi-sense

ExacTech.• 2000-nanotechnology biosensor, chip,quantumdots etc..

Two part of any biosensor

Component

Nucleic acids biosensor• DNA biosensors are being developed as alternatives to

conventional DNA microarrays• The complementary relationships between bases are used

for DNA sequence detection• The reaction take place in the surface of the transducer

ANTIBODY/ANTIGEN:

• The high specificity between an antibody and an antigen can be utilized in this type of sensor technology.

• Biosensors utilizing this specificity to detect the analyte

CELLS AND VIRUSES• Microorganisms such as bacteria and fungi can be used as

biosensors to detect specific molecules or the overall ‘‘state’’ of the surrounding environment

ENZYMES

• Enzyme-based biosensors are composed of enzyme bioreceptors that use their catalytic activity and binding capabilities for specificity biomedical nanostructures detection

Nanoparticle based biosensors

Acoustic wavebiosensorMagnetic biosensorElectrochemical biosensor

Acoustic wave biosensor• The conjugation of antibody modified sol particles which bind

themselves on the electrode surface that has been complexed with the particles of analyte conjugated in a manner that antibody molecules are immobilized over the electrode surface.

• The large mass of bound sol particles of the antibody results in a change in the vibrational frequency of the quartz based sensing platform, and this change acts as the basis of detection.

• In general, the preferred diameter of the sol based antibody particles is between 5 and 100 nm.

• Particles of gold, platinum, cadmium sulphide, and titanium dioxide are generally preferred

Magnetic biosensor

• Utilize the specially designed magnetic nanoparticles.• Mostly ferrite based materials, either used individually or in

combined form. • Useful with reference to the biomedical applications• With the incorporation of magnetic nanoparticles, the

conventionally used biodetection devices have further become more sensitive and powerful.

• specific isolation of magnetically labeled targets with the help of a magnetometer

• Special devices such as superconducting quantum interference devices (SQUID)- for rapid detection of biological targets

• SQUID uses super paramagnetic nature of magnetic nanoparticles.

• These devices are used to screen the specific antigens from the mixtures by using antibodies bound to magnetic nanoparticles

Electrochemical biosensor• To facilitate or analyze the biochemical reactions with the help of

improved electrical means. • Mostly based on metallic nanoparticles. • The chemical reactions between the biomolecules can be easily and

efficiently carried out with the help of metallic nanoparticles, which significantly help in achieving immobilization of one of the reactants.

• This ability makes these reactions very specific and eliminates undesirable side products.

• Example- 1) colloidal gold based nanoparticles have been used to enhance the immobilization of DNA on gold electrodes which has significantly increased the efficiency of an overall biosensor by further lowering the detection limit.

• 2)Enzyme conjugated gold nanoparticles for the identification of glucose, xanthine, and hydrogen peroxide

Nanotube based sensors• Nanocarbons such as carbon powder, carbon nanotubes, graphene

sheets and carbon capsules• Carbon nanotubes –hollow cylinder of a unique carbon sheet with a

single walled carbon nanotube (SWCNT) or concentric carbon sheets of different diameters forming multiwalled carbon nanotubes (MWCNT)

• CNT synthesis by arc-discharge, laser-ablation and chemical vapour deposition

• cylindrical form of CNT- provides quantum confinement effect, possibility to increase the chemical reactivity and electronic properties of this particular carbon material

• high mechanical strength and folding abilities• can enhance the electrochemical reactivity of important

biomolecules

Con…….• can promote the electron-transfer reactions of

proteins• Accumulate important biomolecules (e.g.,nucleic

acids) • Alleviate surface fouling effects• Remarkable sensitivity of CNT- awide range of

electrochemical biosensors ranging from amperometric enzyme electrodes to DNA hybridization biosensors

Biosensor in medical field

Glucose biosensors• In glucose biosensors, use of nanotubes as immobilizing

surfaces for enzyme glucose oxidaze• Use of single walled nanotubes- for enzymatic detection

of glucose• Increased performance- due to the high enzyme loading

and better electrical conductivities of nanotubes• Most glucose biosensors are based on a GOD because

the GOD is able to identify glucose target molecules quickly and accurately through catalyzing glucose to gluconic acid and H2O2

Biosensor for determination of cholesterol

• Electrochemical biosensor for free cholesterol monitoring

• Horseradish peroxidase and cholesterol oxidase are simultaneously immobilized within a polymeric film,

• Which will react with cholesterol

DNA Electrochemical Biosensor for the Detection of HIV

• The sensor relies on the immobilization and hybridization of the 21- or 42-mer single-stranded oligonucleotide from the HIV-1 U5 long terminal repeat (LTR) sequence at carbon paste or strip electrode

• Hybridization between the complementary sequences is determined by the enhancement of the chronopotentiometric peak of the Co(phen)3

3+ indicator

Other example

• Electrochemical DNA biosensor for the detection of TT and Hepatitis B virus

• Biosensor for avian influenza virus detection• Silicon nanowire biosensor for highly sensitive

and rapid detection of Dengue virus

Biosensor assay for determination of haptoglobin in bovine milk

• Mastitis is a disease which reduce the milk quality• Haptoglobin is protein molecule present in the milk• By introducing the antibody specific to the haptoglobin• Developed SPR based biosensor

Multiplex biosensor immunoassaysfor antibiotics

• Based on multi-component antibodies and/or combined immunoassays in serially connected flow channels

• Development of multi-sulfonamide monoclonal antibodies (Mabs)

• Which are immobilize in sensor surface

Example

Sulfonamides detection in Broiler’s blood serum

Screening of Chloramphenicol Residues in Milk

• Chloramphenicol (CAP) are baned use for food producing animals,

• polyclonal antibodies against CAP to immobilized CAP on a sensor chip

• It is mainly spr based biosensor• Which will give the specifity and concentration of

antibiotic

Analysis of b -Lactam Antibiotics• monoclonal H1 antibody is injected across the sensor

surface

• It will bind on the transducer surface

• And it is mainly SPR based optical biosensor

• Analysis of b-lactum necessary due it will create problem in fermentation process in milk

Application in agriculture

• Microbiological control in Foods • Detection of infectious disease in products• Quality control of marketable packaged

products• Quality control of milk• Quality control of fruits• Quality control of meats

Applications of Nanobiosensors

• Biological Applications

• DNA Sensors; Genetic monitoring, disease• Immunosensors; HIV, Hepatitis,other viral diseas, drug

testing, environmental monitoring…• Cell-based Sensors; functional sensors, drug testing…• Point-of-care sensors; blood, urine, electrolytes, gases,

steroids, drugs, hormones, proteins, other…• Bacteria Sensors; (E-coli, streptococcus, other): food

industry, medicine, environmental, other.• Enzyme sensors; diabetics, drug testing,

Environmental Applications

• Detection of environmental pollution and toxicity• Agricultural monitoring• Ground water screening • Ocean monitoring

Future Application

Cancer Monitoring• Nanobiosensors play a very important role for early cancer

detection in body fluids• The sensor is coated with a cancer-specific antibody or

other bio recognition ligands. The capture of a cancer cell or a target protein yields electrical, optical or mechanical signal for detection