Design and Development of Inexpensive Paper-Based Chemosensors for Detection of Divalent Copper

Simple, portable, and low-cost paper-based sensors are alternative devices that have the potential to replace high-cost sensing technologies. The compatibility of the paper base biosensors for both chemical and biochemical accentuates its feasibility for application in clinical diagnosis, environmental monitoring, and food quality monitoring. High concentration of copper in blood serum and urine is associated with diseases like liver diseases, carcinomas, acute and chronic infections, rheumatoid arthritis, etc. Detection of copper concentration can give an early sign of Alzheimer disease. Apart from that genetic Wilson's disease can be detected by evaluating the concentration of copper in the urine. In view of the above advantages, a novel and the highly sensitive paper-based sensor has been designed for the selective detection of Cu²⁺ ions. The fast and highly sensitive chemiresistive multi-dye system sensor can detect Cu²⁺ ions selectively in as low as 2.23 ppm concentration. Least interference has been observed for counter ion in the detection of Cu²⁺. Copper chloride, nitrate, and acetate were used to validate the detection process. This assay provides a very high selectivity of Cu²⁺ ion over other metal cations such as Na⁺, Mg²⁺, Ca²⁺, etc. The easy preparation and high stability of dye solutions, easy functionalization of the paper-based sensors, high selectivity over other cations, low interference of counter anion, and significantly low detection limit of 2.23 ppm make it an effective Cu²⁺ ion sensor for real-time application in near future.