Antibody immobilization for ZnO nanowire based biosensor application
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Antibody immobilization for ZnO nanowire based biosensor application Ankur Gupta, Monalisha Nayak, Deepak Singh, Shantanu Bhattacharya Department of Mechanical Engineering, Indian Institute of Technology Kanpur, U.P. 208016, India ABSTRACT Due to the high surface area and good bio-compatibility of nano structured ZnO, it finds good utility in biosensor applications. In this work we have fabricated highly dense ZnO nano bundles with the assistance of self assembled poly methylsilisesquoxane (PMSSQ) matrix which has been realized in a carpet like configuration with implanted ZnO nano-seeds. Such high aspect ratio structures (~50) with carpet like layout have been realized for the first time using solution chemistry. Nanoparticles of PMMSQ are mixed with a nano-assembler Poly-propylene glycol (PPG) and Zinc Oxide nanoseeds (5-15 nm). The PPG acts by assembling the PMSSQ nanoparticles and evaporates from this film thus creating the highly porous nano-assembly of PMMSQ nanoparticles with implanted Zinc Oxide seeds. Nano-wire bundles with a high overall surface roughness are grown over this template by a daylong incubation of an aqueous solution of hexamethylene tetra amine and Zinc nitrate. Characterization of the fabricated structures has been extensively performed using FESEM, EDAX, and XRD. We envision these films to have potential of highly dense immobilization platforms for antibodies in immunosensors. The principle advantage in our case is a high aspect ratio of the nano-bundles and a high level of roughness in overall surface topology of the carpet outgrowing the zinc-oxide nanowire bundles. Antibody immobilization has been performed by modifying the surface with protein-G followed by Goat anti salmonella antibody. Antibody activity has been characterized by using 3D profiler, Bio-Rad Protein assay and UV-Visible spectrophotometer. KEYWORDS: Composition & Microstructure /Features /morphology, /Functionality /sensor, Synthesis & Processing/Chemical Reaction/sol-gel.
Performance
INTRODUCTION High surface area nanostructured film offers greater sites for biological entities loading capacity, which enhances the sensitivity of biosensor. In order to achieve this, highly oriented ZnO nanowires can be better tool for improving Biosensing performance. The most exigent step in the construction of a biosensor is the immobilization of biomolecules over the surface of the nanowires without loss of biological activity. Antibody immobilization over a substrate/film is very crucial for immuno-sensors which find enormous applications in various fields including clinical and pharmaceutical chemistry, immune-affinity purification of proteins, enzyme reactors as well as in environmental analysis [1-3]. Because of possessing inherently high surface area, good bio-compatibility and non-toxicity, nano structured ZnO film has great potential for biosensor applications. [4]. The diameter of nanostructured material is usually akin to the size of
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the biomolecule, which instinctively makes them outstanding transducers for producing
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