PRELIMINARY CONSTRUCTION OF MICROFIBRILLATED CELLULOSE-BASED BIOFILMS FUNCTIONALIZED WITH COLORIMETRIC INDICATORS FOR FIBER-OPTICAL CALCIUM SENSING

This work describes the production and characterization of microfibrillated cellulose (MFC) biofilms functionalized with colorimetric indicators for the optical detection of calcium ions (Ca²⁺). MFC was characterized and used to produce films using the casting method, with an evaluation of the addition of PVA as a stabilizer of the MFC composite. The biofilms demonstrated good adhesion to optical fiber substrates. They presented a visual colorimetric response in the presence of Ca²⁺, indicating the feasibility of immobilizing the indicators in the cellulose matrix. Preliminary results suggest the potential of these biofilms as low-cost components based on renewable material for the development of optical sensors applicable to environmental and agricultural monitoring.