A recyclable CNC-milled microfluidic platform for colorimetric assays and label-free aged-related macular degeneration detection

Abstract We report the development of a simple, low-cost, and eco-friendly stand-alone 3D microfluidic chemical sensing platform capable of colorimetric and biochemical analyses at the same time. The microfluidic cellulose microfiber (μCM) chip was prototyped by injecting 10% CM mixtures on computer numeric control (CNC)-milled substrates. We show that the μCM chip has a 3-fold faster flow rate than conventional microfluidic paper-based analytical devices and is a recyclable platform that could perform basic microfluidic experiments. The colorimetric assays of the μCM chip can successfully detect clinically relevant concentrations of albumin (R 2  = 0.9994) and glucose (R 2  = 0.9464). The gold nanoparticle-induced surface-enhanced Raman scattering (SERS) label-free bioassay of μCM chips can enhance the Raman signal by 5.15 × 10 8 and a sensitivity of 0.94 (10 pM–1 mM for CV molecules) with an excellent stability of 96% clinical sensitivity and >78% clinical specificity (87% accuracy) from principal component linear discriminant analysis (PC-LDA) model-based multivariate statistical analysis methods.