Silicon nanowire (SiNW) arrays are fabricated using complementary metal-oxide semiconductor (CMOS) compatible technology, for the detection of proteins, pH levels, cardiac biomarker troponin-T (cTnT) etc. The sensor output is fed to a 'current to frequency converter circuit'. Neuromorphic approach based low input referred noise frequency converter circuit is developed. The circuit generates a sequence of spikes with the help of Leaky integrate and fire neuron model (LIF) where firing delay maps to the strength of the stimulation across the array. The proposed read-out circuit is implemented using Tower Jazz Semiconductor's 0.18μm CMOS technology. The SiNW arrays are producing current change from 200pA to 1.6nA for a corresponding change of 50m V/0.5ng/ml protein concentration at the gate. The circuit is able to detect a change in current as low as 50pA and consuming IlμW power and 93×17μm 2 silicon area. © 2018 IEEE.