Detection of C-Reactive Protein Using a Flexible Biosensor with Improved Bending Life

It is well known that regular monitoring of C-reactive protein is beneficial for the self-management of chronic diseases. Herein, a novel tattoo biosensor for regular measurement of C-reactive protein is presented. An innovative approach is presented to boost the life cycle of flexible biosensors in bending tests. Carbon nanotubes were deposited on the biosensor's surface using electrophoretic methods. To assess suspension stability, a zeta potential measurement was performed. Optimized parameters of the electrophoretic procedure were evaluated through scanning electron microscopy imaging. This study shows that carbon nanotube coating increases the biosensor life-cycle by ten times (from 10 to 160 cycles). Using atomic force microscopy, the immobilization of a recognition element (aptamer) on the biosensor's surface was verified. Furthermore, the biosensor's performance was characterized using two electrochemical methods (cyclic voltammetry and impedance spectroscopy). The biosensor achieved a detection range of 0.02 - 0.8 ng ml(-1). The sensor selectivity was examined with a solution of bovine serum albumin, immunoglobin E, interleukin 6, and tumor necrosis factor a. Finally, we carried out a test with the biosensor on spiked human serum samples to confirm that our proposed flexible biosensor can successfully monitor C-reactive protein levels in a range of clinical samples.