A real time immunoassay in alumina membranes

Abstract

Abstract-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 less than 5%. The membranes, with their 200 nm pore diameter enabling targeted delivering of analytes to bioreceptors immobilized on the pore walls, therefore provide a route towards rapid and low cost realtime opto-fluidic biosensors for small sample volumes.

Advances in Optical Biosensors and Sensors Using Nanoporous Anodic Alumina

“…Various applications have been reported for NAA such as biosensors [ 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 ], sensors [ 36 , 66 , 67 , 68 , 69 , 70 , 71 ], drug release [ 72 , 73 , 74 , 75 , 76 ], template-based nanowire, and nanotube fabrication [ 77 , 78 , 79 , 80 ]. Among the various sensors and biosensors that have been reported based on NAA, optical biosensors are the more interesting because of their remote sensing ability and properties such as being small and lightweight, having high sensitivity, and being immune to electromagnetic interference [ 81 , 82 , 83 , 84 , 85 , 86 ].…”