Nano Sensor

If I want to measure something small I need something

smallhellip

BIOSENSOR AND NANOTECHNOLOGY

bull Nanotechnology will enable us to design sensors that are

much smallerless power hungrymore sensitive

What Is Nanotechnology

Richard Feynmanrsquos (1918-1988)

1048698 A nanometre is 11000000000 (1 billionth) of a metre which is around 150000 of the diameter of a human hair or the space occupied by 3-4 atoms placed end-to-end

A few carbon atoms on thesurface of highly orientedpyrolytic graphite (HOPG) Imageobtained by Scanning TunnelingMicroscope (STM)

1048698nanotechnology is a field to understand create and use structures devices and systems that have fundamentally new properties and functions because of their nanoscale structure

1048698 Tools In Nanotechnology

ndash The main tools used in nanotechnology are four main microscopes1ndash Transmission Electron Microscope (TEM)2ndash Atomic Force Microscope (AFM)3ndash Scanning Tunneling Microscope (STM)3ndash Scanning Electron Microscope (SEM)

NANOMATERIALSbull Nanostructured materials have been successfully used in the last

years for the construction of fast accurate and sensitive sensors as they have excellent properties

bull Carbon nanotubes nanowires and nanochannels Quantum dots nanoparticles are all examples of nanomaterials

(The small size of allows for a greater surface to volume ratio)

Carbonnanotubes

Fullerene

Dendrimers

Nanostructures Map

Graphene oxide

bull Graphite when treated with strong oxidizers gives rise to the Graphite oxide which is a compound of carbon oxygen and hydrogen in variable ratios

Manufacture of Graphene Oxidebull Graphene Oxide is formed by oxidizing crystalline graphite with a mixture of

sodium nitrate (NaNO3 sulfuric acid (H2SO4 )and potassium permanganate (KMnO4 )The oxidation method is also known as the Hummers method

bull Structurally the Graphene Oxide is similar to a graphene sheet with its base having oxygen-containing groups Since these groups have an high affinity to water molecules Graphene Oxide is hydrophilic and can be easily dissolved in water

Conthelliphellipbull Graphene Oxide is a poor conductor but when it undergoes treatment using

heat light or chemical reduction most of graphenes properties are restored Chemical reduction is normally done using hydrazine

bull It is possible to deposit Graphene Oxide films on any substrate and then convert it into a conductor These coatings may be used in solar cells flexible electronics chemical sensors liquid crystal devices

bull Graphene which is a conductor graphene oxide is a semiconductors and can replace silicon in electronics applications

conthellip

bull Applications of Graphene Oxidebull Graphene oxide finds application in the

following fieldsbull Transparent conductive films bull Paper-like and composite materials bull Energy-related materials bull Biological and medical applications

Graphenebull Graphene is one of the allotropic forms of carbon

bull It is a one-atom-thick planar sheet of carbon atoms that are densely packed in a honeycomb crystal lattice

bull Graphite itself consists of many graphene sheets stacked together

bull The carbon-carbon bond length in graphene is approximately 0142 nm

Graphene production

bull Researchers obtained relatively large graphene sheets by mechanical exfoliation (repeated peeling) of 3D graphite crystals

bull Another method is to heat silicon carbide to high temperatures (1100degC) to reduce it to graphene

bull Graphene has excellent properties like Its entire volume is exposed to its surrounding High electrical conductivity

The functionalized graphene biosystems

Nucleic acids

Avidin- biotin Peptide

Cells

AptamersBacteria

Proteins

Nanofabrication methods

BIOSENSOR AND CANCERbull Cancer is an abnormal and an uncontrolled cell growth

due to an accumulation of specific genetic and epigenetic defects

bull Biosensor technology has the potential to provide fast and accurate detection reliable imaging of cancer cells monitoring of angiogenesis and cancer metastasis ability to determine the effectiveness of anticancer

chemotherapy agents

Preexisting technology

Existing cancer screening methods includebull (1) the CA 153 test and mammography to detect breast

cancer in womenbull (2) prostate-specific antigen (PSA) level detection in blood

sample for men to detect prostate cancerbull (3) blood detection for colon cancerbull (4) endoscopy CT scans X-ray ultrasound imaging and

MRI for various cancer detection

Conthellip These traditional diagnostic methods however

are not very powerful methods -bull as they can not detect cancer at very early

stages bull some of the screening methods are quite costly

and not available for many people so use of biosensors to detect cancer biomarkers

in serum has spread widely

Biomarkers

bull In terms of cancer the analyte being detected by the biosensor is a tumor biomarker

bull A biomarker is an indicator of a biological state of disease

bull Biomarkers can be DNA RNA or protein (ie hormone antibody oncogene or tumor suppressor)

Fig Application of the biosensor The use of biosensors to detect tumor markers in serum has spread widely (Jin 2011)

OBJECTIVESbull Surface modification of nanoporous membrane by

graphene oxidebull Characterization of graphene coated nanoporous

membrane by SEMbull Immobilization of antibody on nanoporous membranebull Characterization of immobilized nanoporous

membranebull Fabrication of nanoimmunosensorbull Detection of samplebull Standardization of protocol of nanoimmunosensors

Surface modification of nanoporous membrane by graphene oxide

(1)Coating of the graphene oxide onto the nanoporous membrane by drop coating method

bull Drop wise graphene is poured onto the membrane

bull A thin film is obtained onto the membrane surface

CHARACTERIZATION OF GRAPHENE COATED MEMBRANE BY SEM

The membranes categorized in two different classes-

(1) PCTE membrane was used as such

(2) PCTE membrane coated with graphene nanolayer over

the one surface of membrane with the help of drop coating

method

Functionalization of graphene modified membrane

contbull Graphene is incubated with linker molecule in

dimethylformamide (DMF)bull The linker-modified graphene then incubated with

antibody in Na2CO3-NaHCO3 buffer solution (pH 90) overnight at 40C followed by rinsing with DI water and phosphate buffered saline solution (PBS)

bull Raman spectroscopy in particular has been found to be a valuable tool to elucidate the structural properties of graphene

Conthellip

Fig 1 (A) Raman map and spectrum of graphene film The map isconstructed by plotting the peak width at half height of the 2D-band asthe pixel intensity Scale bar frac14 08 mm (B) AFM image of the graphenefilm Scale bar frac14 500 nmThis journal is ordf The Royal Society of Chemistry 2011 J Mater

CHARACTERIZATION OF IMMOILIZED GRAPHENE

Electron microscopy (TEM and SEM) and atomic force microscopy have been used to characterize the graphene

FABRICATION OF NANOIMMUNOSENSOR

(A) Fitting of immobilized membrane into glass cells

(B) Development of appropriate electronic circuit

(C)Recording of amperometric signals with proper Ab-

Ag actions

STANDARDIZATION OF PROTOCOL OF NANOIMMUNOSENSOR

(A)Recording of amperometric data

(B)Digitalization of signals and recording

CONCLUSION

conclusionbull In present work a graphene modified PCTE (polycarbonate Track

Etch)membrane is used in nanoimmunosensors which can be employed to detect specific cell membrane-associated target antigens

bull The morphology of graphene modified nanoporous membrane was characterized by Scanning Electron Microscopy and chemical analysis was completed by FTIR (Fourier Transform Infrared Spectroscopy) prior to use in nanobiosensor

bull This antibody immobilized membrane structure was then tested with a no of few antigens and cross checked by structurally related antigens for specificity

• If I want to measure something small I need something smallhellip
• BIOSENSOR AND NANOTECHNOLOGY
• What Is Nanotechnology
• 1048698 Tools In Nanotechnology
• NANOMATERIALS
• Nanostructures Map
• Graphene oxide
• Conthelliphellip
• conthellip
• Graphene
• Graphene production
• The functionalized graphene biosystems
• Nanofabrication methods
• BIOSENSOR AND CANCER
• Preexisting technology
• Conthellip
• Biomarkers
• Slide 18
• OBJECTIVES
• Surface modification of nanoporous membrane by graphene oxid
• CHARACTERIZATION OF GRAPHENE COATED MEMBRANE BY SEM
• Functionalization of graphene modified membrane
• cont
• Conthellip
• CHARACTERIZATION OF IMMOILIZED GRAPHENE
• FABRICATION OF NANOIMMUNOSENSOR
• STANDARDIZATION OF PROTOCOL OF NANOIMMUNOSENSOR
• CONCLUSION
• conclusion
• Slide 30