High yield two-dimensional (2-D) polyaniline layer and its application in detection of B-type natriuretic peptide in human serum

The demand for ultrasensitive and inexpensive biosensors is always strong due to increasing healthcare related concerns. Herein, we developed a simple method to prepare uniform, reliable, high yield, and low-cost two-dimensional (2-D) polyaniline layer for biosensor applications. The 2-D PANI layer's surface morphology led to a 46% increase in surface area compared to a flat 2-D surface. Due to this unique morphology and excellent semiconducting properties, the 2-D PANI layer exhibited ultrasensitive performance with excellent specificity on BNP biomarker detection in fixed Debye length condition, which is comparable to or even higher than 1-D nanostructure biosensors. In further Debye length investigation, we have observed signal changes that are varied from 8 nA to 16 nA with Debye length changes from 0.5 nm to 3.3 nm for constant BNP concentration. This result shows an improvement in device sensitivity over increasing Debye length, which conforms to Debye screening theory. With the high specificity of over 400 fold, the PANI layer was capable of monitoring significantly low BNP levels in human serum, as low as 50 pg/mL. Our findings provide an opportunity for the realization of ultrasensitive and inexpensive biosensors for clinical use.