Applicability of the Reaction Layer Principle to Nanoparticulate Metal Complexes at a Macroscopic Reactive (Bio)Interface: A Theoretical Study

Abstract

The reaction layer concept is commonly adopted to estimate the contribution of metal complexes to the flux of free metal ions (M) toward a macroscopic M-accumulating (bio)interface, e.g., a biosurface (microorganism) or a sensor (electrode). This concept is well-established for molecular ligands homogeneously distributed in solution. However, the case of (nano)particulate complexants carrying metal binding sites within their body or at their surface has so far received scant attention. In this study, a formalism is elaborated to evaluate the thickness λ of the reaction layer that is operational for (nano)particulate metal complexes at a macroscopic metal-sensing (bio)interface. The theory integrates the relevant chemodynamic properties of nanoparticulate metal complexes as governed by the interplay between M conductive diffusion to/from the nanoparticulate complexants and the dissociation kinetics of inner-sphere complexes between M and particle-supported binding sites. The intricate dependence of λ on ...