Nanocellulose-Based Biosensors: Design, Preparation, and Activity of Peptide-Linked Cotton Cellulose Nanocrystals Having Fluorimetric and Colorimetric Elastase Detection Sensitivity

Abstract

Nanocrystalline cellulose is an amphiphilic, high surface area material that can be easily functionalized and is biocom- patible and eco-friendly. It has been used singularly and in combination with other nanomaterials to optimize biosensor design. The attachment of peptides and proteins to nanocrystalline cellulose and their proven retention of activity pro- vide a route to bioactive conjugates useful in designs for point of care biosensors. Elastase is a biomarker for a number of inflammatory diseases including chronic wounds, and its rapid sensitive detection with a facile approach to sensing is of interest. An increased interest in the use of elastase sensors for point of care diagnosis is resulting in a variety of ap- proaches to elsastase sensors utilizing different detection technologies. Here elastase substrate peptide-celluose conju- gates synthesized as colorimetric and fluorescent sensors on cotton cellulose nanocrystals are compared. The structure of the sensor peptide-nanocellulose crystals when modeled with computational crystal structure parameters demon- strates the spatio-stoichiometric features of the nanocrystalline surface that allows ligand to active site protease interact- tion. An understanding of the structure/function relations of enzyme and conjugate substrate of the peptides covalently attached to nancellulose has implications for enhancing the biomolecular transducer. The potential applications of both fluorescent and colorimetric detection to markers like elastase using peptide cotton cellulose nanocrystals as a trans- ducer surface to model point of care biosensors for protease detection are discussed.