Lab-on-a-bead: Polymeric natural deep eutectic solvents as a versatile platform for (bio)sensor design

Abstract

Natural polymers offer not only low-cost, wide availability, biocompatibility, and biodegradability but also a rich chemical functionality towards custom modifications and new applications. Among those, sodium alginate (ALG) offers several competitive advantages, including the possibility to form beads by a simple process call spherification as well as their modification by a wide number of processes, including the possibility to mixing the alginate solution with deep eutectic solvents (DES). Thus, and considering the capacity of DES to stabilize enzymes, the main objective of this work was to design and fabricate a new polymeric DES (using ALG as one of the components, ALGPODES) and to deploy this material as a new phase to develop colorimetric biosensors. The formed beads displayed a narrow size distribution (2.9 ± 0.1 mm) and a permeable structure with large internal cavities (25–100 µm). The applicability of these beads towards analytical applications (lab-on-a-bead) was demonstrated by integrating three sensing platforms and by their application in real food samples.