Development of Dendrimer Magnetic Nanoparticle Based Electrochemical Biosensors

Abstract

Biosensors as a point-of-care bioanalytical device offers the potential for rapid and reliable newlinetesting of sample analytes in clinical diagnostic application. It presents advantages of being newlineportable, easy- to-use device and cost-effective. In recent years, nanomaterials have been newlineextensively employed for designing platforms for biosensor. Electrochemical-based biosensor, newlinewhen integrated with nanomaterials, has an advantage in significantly enhancing signal newlineresponse and sensitivity. In this study, magnetic nanoparticles (Fe3O4 NPs) and polyamidoamine newline(PAMAM) dendrimers were chosen as signal enhancement materials. Small-sized newlineFe3O4 NPs exhibit superparamagnetism which was employed for magneto-separation process newlineduring nano-bioconjugate formation. However, Fe3O4 NPs tends to agglomerate and oxidize newlinevery easily. Therefore, PAMAM dendrimers (four systems, with two different generations and newlinecore molecule) were coated onto core Fe3O4 surface by in-situ modified chemical coprecipitation newlinemethod and were characterized using FT-IR, XRD, TGA, VSM, TEM, zeta newlinepotential, BET and XPS. PAMAM dendrimers not only act as stabilizers but also provides high newlinesurface area for immobilization of biomolecules. Thus, PAMAMatFe3O4 NPs act as signal newlineamplification probes which helps to increase sensitivity and specificity of biosensor. newlineElectrochemical behaviour of the NPs was studied by cyclic voltammetry (CV) and electrontransfer newlinekinetics was analysed by varying the scan rates. This step indicated a diffusioncontrolled newlineredox process of the NP system. Further, the biosensing platform was developed newlinebased on electrochemical immunosensing to specifically detect hepatocellular carcinoma newline(HCC) specific biomarkers. Since no single biomarker is unique for particular cancer detection, newlineherein, a combination of two HCC-specific serum biomarkers; alpha-fetoprotein (AFP) and newlineglypican-3 (GPC-3) were selected. Thus, the biosensor based on PAMAMatFe3O4 NPs newlineplatform was developed for simultaneous detection of AFP and GPC-3 biomarkers. newline