Nanobiosensors

Nabeel.B.AzeezFatih University

But these are not nanobiosensors ……….

Blood test

WHAT IS NANOBIOSENSORS ? A biosensor is a measurement system for the detection of an analyte that combines a biological component with a physicochemical detector, and a nanobiosensoris a biosensor that on the nano-scale size

Diversity of biosensors

Current Definition for Biosensors:

A sensor that integrates a biological element with a physiochemical transducer to produce an electronic signal proportional to a single analyte which is then conveyed

to a detector.

Components of a Biosensor

Detector

1ST Component: Biological Element

Microorganism

Tissue

Cell

Organelle

Nucleic Acid

Enzyme

Enzyme Component

Receptor

Antibody

The component used to bind the target molecule.

Must be highly specific, stable under storage conditions, and immobilized.

2ND Component: Physiochemical Transducer

Acts as an interface, measuring the physical change that occurs with the reaction at the bioreceptor then transforming that energy into measurable electrical output.

3RD Component: Detector

Signals from the transducer are passed to a microprocessor where they are amplified and

analyzed.

The data is then converted to concentration units and transferred to a display or/and data storage device.

Principles of Detection

measures change in mass

measures change in electric distribution

measures change in light intensity

measures change in heat

Principles of DetectionPiezo-Electric Biosensors

The change in frequency is proportional to the mass of absorbed material.

Some piezo-electric devices utilize crystals, such as quartz, which vibrate under the influence of an electric field. The frequency of this oscillation

depends on their thickness and cut.

Others use gold to detect the specific angle at which electron waves (surface plasmons) are

emitted when the substance is exposed to laser light.

Principles of DetectionElectrochemical Biosensors

•Amperometric for applied current: Movement of e- in redox reactions detected

when a potential is applied between two electrodes.

•Potentiometric for voltage: Change in distribution of charge is detected using

ion-selective electrodes, such as pH-meters.

•Conductimetric for impedance

Principles of Detection

Optical Biosensors

•Colorimetric for color: Measure change in light adsorption as reactants are converted to products.

•Photometric for light intensity: Photon output for a luminescent or fluorescent process can be detected with photomultiplier tubes or photodiode systems.

Principles of DetectionCalorimetric Biosensors

If the enzyme catalyzed reaction is exothermic, two thermistors may be used to measure the difference in resistance between reactant and product and, hence, the analyte concentration.

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, other.Environmental Applications• Detection of environmental pollution and toxicity• Agricultural monitoring• Ground water screening • Ocean monitoringMilitary Applications

Personalized Medicine

Integrating sensors with mobile sensors

Lab on a chip technologies

• The article developed optical biosensors for monitoring (

carboplatine – DNA interaction based on FRET.

• The interaction of DNA and Carboplatin was studied with DNA

labeled (AuNPs) based optical nanobiosensor. Carboplatin, a

cytotoxic drug, is responsible for producing nephrotoxicity at

effective dose .

• The major difference in increased fluorescence intensity between

carboplatin–DNA and paracetamol– DNA interaction shows

significant observations. Results have demonstrated that Optical

sensor is able to rapidly and effectively monitor carboplatin–

DNA interaction with a detection limit up to 0.45 mg/ml

• The developed optical nanobiosensor was ideal for monitoring

Drug–DNA interaction studies while performing combinatorial

synthesis for new drug development.

FRET assays are often used to identify the

interaction of two molecule . one molecule is

labeled with a fluorescence acceptor , which

is excited only when a molecule – usually a

binding partner – bearing a fluorescence

donor in the vicinity

Irrespective of the photo – physical

characteristic of the acceptor, i.e.

whether it is a chromophore or

fluorophore the energy transfer

process called as : foster

resonance energy transfer

colloquially referred to as fluorescence resonance energy transfer

the SEM image of AuNPs. Shows

The particles were predominantly spherical

in shape with diameter ranging 20 + 5nm. .

Larger particles with diameter 40 + 10 nm

were also obtained .

the average fluorescence intensity of the carboplatin–DNA and paracetamol–

DNA interaction obtained by collecting data from three independent mea-

surements at the same conditions. The results showed that the fluorescence

intensity of carboplatin–DNA interaction was enhanced along with the increase

of carboplatin concentration. While, the fluorescence intensity of paracetamol–

DNA interaction increased slightly, this suggested that a very weak interaction is

occurring

The comparisons of analytical performances for

determining carboplatin–DNA and

paracetamol–DNA interaction

• the facile fabrication of a self-reporting, highly sensitive

and selective optical urea nanobiosensor using chitosan-g-

polypyrrole (CHIT-g-PPy) nanomicelles as a sensing

platform. Urease was immobilized on the spherical

micellar surface to create an ultrasensitive self-reporting

nanobiosystem for urea.

• This promising approach provides a novel methodology for

self-reporting bio-assembly over nanostructure polymer

micelles and furnishes the basis for fabrication of sensitive

and efficient optical nanobiosensors.

• Owing to the selective hydrolysis of the urea, the proposed

nanoreactor could be used in the development of artificial

kidneys.

compares the performance of previously reported

enzymatic and non-enzymatic urea sensors. In comparison to

other conventional analytical methods, the 0current biosensing

approach has improved detection limits,specificity and

response time.

The synthesis strategy was to obtain CHIT-

g-PPy spherical nanomicelles via covalent

bonding and then to conjugate the enzyme

on the spherical micelles. This allowed

optical sensing of various concentration of

urea.

The size of the CHIT-g-PPy and

Urs/CHIT-g-PPy micelles was

determined by DLS and the results are

shown in this paragraph .

DLS number size distribution of

micellar nanostructure before (

CHIT – g- PPy ) and after enzyme

immobilization ( CHIT – g- PPy/ Urs

)

The size and morphology of CHIT-g-

PPy and Urs/CHIT-g-PPy micelles was

further characterized by transmission

electron microscopy (TEM) and the

Panel shows CHIT-g-PPy nanomicelles

and llustrates the formation of a

multicomponent micelle-type

structure, due to the successful graft

copolymerization between CHIT and

PPy

• A very sensitive and convenient fluorescence nanobiosensor for rapid detection of DNA methylation based on Fe3O4/Au core/shell nanoparticles has been developed and studied tumor suppressor gene, was used as the detection target DNA sequence

• Fe@Au nano particles functionalized by bounding of single stranded DNA (ssDNA) probe through sulfhydryl group at the 50 phosphate end.

• We have also shown that nanobiosensor could distinguish ratio of methylation in series of partially methylated DNA targets with identical sequences. A density functional theory (DFT) calculation was also performed to investigate the interaction between Dipyridamole with unmethylated and methylated cytosine

• Finally real sample analysis suggested that nanobiosensor could have practical application for methylation detection in human plasma sample

Fe@Au nanoparticles have been used for immobilizing of ssDNA probe and magneticallyseparation of captured ssDNA targets and Dipyridamole used as a fluorescence probethat binds and interacts with double stranded DNA which distinguishs betweenmethylated and unmethylated DNA sequences through different fluorescencebehavior.An over- view of the detection mechanism is illustrated in Scheme

Electron microscopy analysis The shape and size of the nanoparticles were determined by SEM images of the nanoparticles after and before the shell formation which is shown in Fig. 1a and b.The nanoparticles appeared nearly spherical and had an average diameter of about 25 nm and 30nm for Fe3O4 and Fe@Au one srespectively. The increase in the diameter of the some nanoparticles could be not only due to gold coating,but also to the aggregation of several Fe3O4 nanoparticles coated by the same gold shell

The EDS spectra also confirmed the composition of nanoparticles and demon- strated the

presence of Au ,Fe and O elements

TEM image of a single Fe@Au

nanoparticle showed the spherical shape and also indicated highly efficient attachment of very thing old shell around Fe3O4 nanoparticle with thickness about 1.2nm

a data set table to compare the present obtained results with the previous studies on the

methylation recognition by different detection techniques. From the view of linear

range and detection limit, the proposed method showed the priorities over the

mentioned reports

* sample condition used in human blood

plasma as a hybridization buffer. The blood samples were centrifuged at 12,000 rpm for 10 min and then the upper plasma solution carefully removed and transferred to a new vial

* results illustrated that nanobiosensor

could have practical application for methylation detection in real sample.