A Point-of-Care Immunosensor for Human Chorionic Gonadotropin in Clinical Urine Samples Using a Cuneated Polysilicon Nanogap Lab-on-Chip

• DOI: 10.1371/journal.pone.0137891
• Publication Date: 2015-09-14T18:43:59Z
• Authors: S. R. Balakrishnan; U. Hashim; Subash C. B. Gopi...; P. Poopalan; H. R. Ramayya; M. Iqbal Omar; R. Haarindraprasad; P. Veeradasan
• Keywords: Human chorionic gonadotropin

Human chorionic gonadotropin (hCG), a glycoprotein hormone secreted from the placenta, is key molecule that indicates pregnancy. Here, we have designed cost-effective, label-free, in situ point-of-care (POC) immunosensor to estimate hCG using cuneated 25 nm polysilicon nanogap electrode. A tiny chip with dimensions of 20.5 × 12.5 mm was fabricated conventional lithography and size expansion techniques. Furthermore, sensing surface functionalized by (3-aminopropyl)triethoxysilane quantitatively measured variations levels clinically obtained human urine samples. The dielectric properties present sensor are shown capacitance above 40 nF for samples pregnant women; it lower non-pregnant women. has been proven our wide linear range detection, as sensitivity 835.88 μA mIU(-1) ml(-2) cm(-2) attained, detection limit 0.28 mIU/ml (27.78 pg/ml). dissociation constant Kd specific antigen binding anti-hCG calculated 2.23 ± 0.66 mIU, maximum number sites per Bmax = 22.54 1.46 mIU. system here, narrow nanogap, suitable high-throughput POC diagnosis, single injection can obtain triplicate data or parallel analyses different targets.