Prof. Abraham Lee was the second speaker of the day and talked about using Microfluidic Acoustic Cavity Transducers or in simple terms using air bubbles for mixing in microfluidics channels. Bubbles can enhance mixing and increase the kinetics of the binding. A log order improvement is seen in proof-of-concept immunoassays and significant improvement is seen when these type of mixing were applied to protein arrays. The protein array work was done in collaboration with from Felgner lab. There is a company (can’t remember the name) that can mix liquids in small drops for mixing and speeding up the diffusion.
Prof. Mike Sailor followed Prof. Lee and he talked about using porous silicon nanostructures for in-vitro and in-vivo diagnostics application. These silicon nanostructures have different light reflectance properties based on their nanoporous structures. He gave example of Abalone shells that are iridescent because of similar phenomenon.
Abalone Shell (credit Wikipedia)
The optical properties of thin film of porous silicon nanostructures changes based on how these nanopores fill up with liquids or small protein fragments and can be used for biosensing applications. One biological example he talked about was using this for protease assays. In presence of protease, casein is cleaved into small fragments that can fill up the pores and hence change the optical properties of the silicon nanopore sensor. These nanoporous structures can be lift-off from thin film structures and these micron sized particles act as spectrally encoded particles and can be used for multiplexed biosensing. These micron sized particles can be sonicated and broken into nano sized particle and can be used for in-vivo imaging. Some of his papers available on Google Scholar are here. Biomolecular screening with encoded porous photonic crystals and Biosensing Using Porous Silicon Double-Layer Interferometers and Biomimetic amplification of nanoparticle homing to tumors — PNAS.