Nanobiosensors
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The document discusses nanobiosensors, which are measurement systems that integrate biological elements with physicochemical detectors at the nanoscale for high sensitivity in analyte detection. It details various components and detection principles of biosensors, including electrochemical, optical, and calorimetric methods, along with their applications in biological and environmental monitoring. Specific examples include the development of optical nanobiosensors for monitoring drug-DNA interactions and enhanced sensitivity in detecting DNA methylation in human plasma.
Nanobiosensors
- 3. But these are not nanobiosensors ā¦ā¦ā¦.
- 5. Blood test
- 6. 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
- 9. 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.
- 10. Components of a Biosensor Detector
- 11. 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.
- 12. 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.
- 13. 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.
- 14. Principles of Detection measures change in mass measures change in electric distribution measures change in light intensity measures change in heat
- 15. Principles of Detection Piezo-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.
- 16. Principles of Detection Electrochemical Biosensors ā¢Amperometric for applied current: Movement of e- in redox reactions detected when a potential is applied between two electrodes. ā¢Potentiometric for voltage: Change in distribution of charge is detected using ion-selective electrodes, such as pH-meters. ā¢Conductimetric for impedance
- 17. Principles of Detection Optical Biosensors ā¢Colorimetric for color: Measure change in light adsorption as reactants are converted to products. ā¢Photometric for light intensity: Photon output for a luminescent or fluorescent process can be detected with photomultiplier tubes or photodiode systems.
- 18. Principles of Detection Calorimetric 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.
- 19. Applications of Nanobiosensors Biological Applications ā¢ DNA Sensors; Genetic monitoring, disease ā¢ Immunosensors; HIV, Hepatitis,other viral diseas, drug testing, environmental monitoringā¦ ā¢ Cell-based Sensors; functional sensors, drug testingā¦ ā¢ Point-of-care sensors; blood, urine, electrolytes, gases, steroids, drugs, hormones, proteins, otherā¦ ā¢ Bacteria Sensors; (E-coli, streptococcus, other): food industry, medicine, environmental, other. ā¢ Enzyme sensors; diabetics, drug testing, other. Environmental Applications ā¢ Detection of environmental pollution and toxicity ā¢ Agricultural monitoring ā¢ Ground water screening ā¢ Ocean monitoring Military Applications
- 21. Integrating sensors with mobile sensors
- 22. Lab on a chip technologies
- 24. ā¢ The article developed optical biosensors for monitoring ( carboplatine ā DNA interaction based on FRET. ā¢ 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 . ā¢ The major difference in increased fluorescence intensity between carboplatināDNA and paracetamolā DNA interaction shows significant observations. Results have demonstrated that Optical sensor is able to rapidly and effectively monitor carboplatinā DNA interaction with a detection limit up to 0.45 mg/ml ā¢ The developed optical nanobiosensor was ideal for monitoring DrugāDNA interaction studies while performing combinatorial synthesis for new drug development.
- 25. 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 ā usually a binding partner ā bearing a fluorescence donor in the vicinity Irrespective of the photo ā 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
- 26. 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 .
- 27. the average fluorescence intensity of the carboplatināDNA and paracetamolā DNA interaction obtained by collecting data from three independent mea- surements at the same conditions. The results showed that the fluorescence intensity of carboplatināDNA interaction was enhanced along with the increase of carboplatin concentration. While, the fluorescence intensity of paracetamolā DNA interaction increased slightly, this suggested that a very weak interaction is occurring The comparisons of analytical performances for determining carboplatināDNA and paracetamolāDNA interaction
- 29. ā¢ 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. ā¢ 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. ā¢ Owing to the selective hydrolysis of the urea, the proposed nanoreactor could be used in the development of artificial kidneys.
- 30. 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.
- 31. 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.
- 32. 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 ā g- PPy ) and after enzyme immobilization ( CHIT ā 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
- 34. ā¢ 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 ā¢ Fe@Au nano particles functionalized by bounding of single stranded DNA (ssDNA) probe through sulfhydryl group at the 50 phosphate end. ā¢ 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 ā¢ Finally real sample analysis suggested that nanobiosensor could have practical application for methylation detection in human plasma sample
- 35. Fe@Au nanoparticles have been used for immobilizing of ssDNA probe and magnetically separation of captured ssDNA targets and Dipyridamole used as a fluorescence probe that binds and interacts with double stranded DNA which distinguishs between methylated and unmethylated DNA sequences through different fluorescence behavior.An over- view of the detection mechanism is illustrated in Scheme
- 36. 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
- 37. 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
- 38. 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.