Tannin-furanic foams used as biomaterial substrates for SERS sensing in possible wastewater filter applications

Simple substrates for surface enhanced Raman spectroscopy (SERS), producible in a cost-efficientway, are of growing interest both for scientific and for environmental applications. In this study,we demonstrate the use of three types of bio-based tannin-furanic rigidfoams asprecursormaterials forSERSsubstrates. Coated with a silver layer, these substrates allowed the detection of several well-knownanalytes in themM regime by Raman spectroscopy. Specific optimization of the standard tannin-furanic foammorphology by tuning the chemical synthesis led to a smaller and more homogeneously distributed pore structure, supplyingmoreactivehot spot areas.Thus,we obtained a significant increase and a lower relative standard deviation (RSD) of the SERS signal recorded over themapped SERS substrate area, for several analytes, in particular forMalachite Green dye.Thiswork represents a feasibility study opening several potential applications of this biopolymers in fields such as the detection of water pollutants, virtually combining filtration and SERS capabilities driven by a controlled porosity.