Metal-Free Cellulose-Based Platforms for Biomolecule Fluorescence Signal Enhancement

Fluorescence is a rapid and noninvasive technique for analyte detection. Green, sustainable, and safe materials that enhance the analyte fluorescence signal possess the potential to create new green photonic technologies for medical diagnostics. Here, we report that metal-free cellulose-based substrates can be used as platforms to enhance the fluorescence signal from a model immunoassay as well as a wide variety of molecules by over an order of magnitude. The cellulose-based sensing platforms are cost-effective, biocompatible, robust, and result in a reproducible signal variation as low as 16%. We show that molecules at concentrations as low as 100 nM can be detected on cellulose-based substrates. We attribute the observed enhancement to nanofiber-driven clustering of the analyte molecules, high surface roughness, as well as a charge-transfer process.