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This presentation discusses the integration of biotechnology, electro-optics, and laser technology, which have recently opened new horizons to the development of advanced biosensors for industrial, environmental, biomedical, and biotechnology applications.
Biosensors are powerful tools aimed at providing selective identification of toxic chemical compounds at ultratrace levels in industrial products, chemical substances, environmental samples (e.g., air, soil, and water) or biological systems (e.g., bacteria, virus, or tissue components) for biomedical diagnosis. Combining the exquisite specificity of biological recognition probes and the excellent sensitivity of laser-based optical detection, biosensors are capable of detecting and differentiating big/chemical constituents of complex systems in order to provide unambiguous identification and accurate quantification. A new generation of biosensors discussed in this presentation uses antibody and DNA probes.
Antibody-based fluoroimmunosensors (FISs) have been developed for the carcinogen benzo[a]pyrene (BaP) and related adducts such as benzopyrene tetrol (BPT). Polyclonal or monoclonal antibodies produced are immobilized at the terminus of a fiber optics probe or contained in a micro-sensing cavity within the FIS for use both in in-vitro and in-vivo fluorescence assays. High sensitivity is provided by laser excitation and optical detection. The FIS device utilizes the back-scattering of light emitted at the remote sensor probe. A single fiber is used to transmit the excitation radiation into the sample and collect the fluorescence emission from the antigen. The laser radiation reaches the sensor probe and excites the BaP bound to the antibodies immobilized at the fiberoptics probe. The excellent sensitivity of this device illustrates that it has considerable potential to perform trace analyses of chemical and biological samples in complex matrices. Measurements are simple and rapid (~ 5 min), and the technique is applicable to other compounds provided appropriate antibodies are used.
Biochips: We have recently investigated a new generation of biosensors using DNA probes (DNA Biochip). Probe recognition is based on the molecular hybridization process, which involves the joining of a strand of nucleic acid with a complementary sequence. Biologically active DNA probes are directly immobilized on optical transducers which allow detection of Raman, SERS, or fluorescent probe labels. DNA biosensors could have useful applications in areas where nucleic acid identification is involved. The DNA probes could be used to diagnose genetic susceptibility and diseases. The Biochip using antibody probes has recently been developed to detect the p53 protein system.