A real time immunoassay in alumina membranes

J. Álvarez, L. Sola, M. Cretich, M. J. Swann, K. B. Gylfasson, T. Volden, M. Chiari, D. Hill

Research output: Contribution to journalConference articlepeer-review


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.

Original languageEnglish
Article number6985365
Pages (from-to)1760-1763
Number of pages4
JournalProceedings of IEEE Sensors
Issue numberDecember
Publication statusPublished - 15 Dec 2014
Event13th IEEE SENSORS Conference, SENSORS 2014 - Valencia, Spain
Duration: 2 Nov 20145 Nov 2014


  • Copolymer
  • Form birefringence
  • Optical biosensing
  • Polarimetry
  • Porous alumina
  • Quantum dots


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