Nanofilms as universal coatings for biosensors

Ultrathin nanofilm coatings can play a key role for micro/nanoscale biosensor applications. Most flux-based enzymatic biosensors require incorporation of a diffusion-limiting coating to balance the flux of incoming substrates with reaction kinetics to obtain a measurable signal. Furthermore, the outer surface requires resistance to nonspecific adsorption of protein to prevent cell adhesion and host response initiation when deployed in vivo. However, materials suited for application to micro/nanoscale sensors are difficult to find. Polyelectrolyte mutilayers (PEMs) deposited via layer-by-layer (LbL) self-assembly are attractive solutions, as they offer nanocomposite films with tunable properties such as permeability and biocompatibility. In this paper, we explored the diffusion characteristics of nanofilms with different compositions including biocompatible surfaces, and investigated multiple analytes such as glucose, urea, and L-lactate to assess universal applications of these nanofilms as biosensor coatings.