(191bu) Protein Detection Using Paper-Based Graphene Ink Biosensors from a Flexographic Proofer

A low-cost graphene ink-based biosensor was developed using a flexographic proofer with paper and non-paper substrates. Due to low-cost materials and an easy-to-follow device fabrication procedure, these biosensors are attractive as lab-on-a-chip devices for rapid diagnosis. These biosensors require no pumps for testing, and testing can be performed on a multimeter in a matter of minutes. A printing procedure was developed to fabricate biosensors using graphene inks from XG Sciences on which electrical resistivity measurements can be performed to detect bovine serum albumin (BSA) in phosphate buffer (PB). Various paper substrates including copy paper, chromatography-grade filter paper, and Tyvek were used with different size anilox rolls for printing. A polyethylene terephthalate (PET) substrate was used as a non-porous printing substrate for a control with protein detection tests. From electrical resistivity measurements on a Keithley 2400 SourceMeter, the graphene ink-copy paper biosensors were able to detect the presence of BSA in a PB solution. These biosensors can be further enhanced by functionalizing with anti-BSA to specifically bind and detect BSA in a non-ideal solution. Paper-based, graphene biosensors have the high potential to aid in the development of inexpensive biosensors that could prove useful in medical diagnostics in underdeveloped countries.