0000000000367917
AUTHOR
Tormod Volden
A real time immunoassay in alumina membranes
To date, photonic biosensing with porous membranes has produced slow responses and long sensing times, due to the narrow (less than 100 nm) closed end pores of the membranes used. Recently, polarimetry was used to demonstrate analyte flow through, and real time biosensing in, free-standing porous alumina membranes. Here, we demonstrate how an improved functionalization technology, has for the first time enabled a real-time immunoassay within a porous membrane with a total assay time below one hour. With the new approach, we show a noise floor for individual biosensing measurements of 3.7 ng/ml (25 pM), and a bulk refractive index detection limit of 5×10-6 RIU, with a standard deviation of l…
Real time optical immunosensing with flow-through porous alumina membranes
Through the presentation of analytical data from bioassay experiments, measured by polarimetry, we demonstrate for the first time a real time immunoassay within a free standing macroporous alumina membrane. The 200 nm nominal pore diameter of the membrane enables flow-through, thereby providing an ideal fluidic platform for the targeted delivery of analytes to bioreceptors immobilized on the pore walls, enabling fast sensing response times and the use of small sample volumes (<100 mu L). For the immunoassay, the pore walls were first coated with the functional copolymer, copoly(DMA-NAS) using a novel coupling process, before immobilization of the allergen protein, beta-lactoglobulin, by spo…