In this paper, a four-channel floating-gate-based analog front-end (AFE) integrated circuit is presented. Each channel consists of a low noise amplifier (LNA), two operational- transconductance-amplifier-capacitor (OTA-C) biquadratic filters and two buffer amplifiers. Floating-gate transistors deployed in a two-dimensional array are utilized to facilitate circuit reconfigurability and to achieve better power efficiency. Floating-gate programming circuities are also designed on-chip. Furthermore, a serial-peripheral interface (SPI) circuit with floating-gate transistors as non-volatile memories is adopted as the circuit parameter storage as well as the control interface during floating-gate programming. A prototype chip is design and fabricated in a 0.35um CMOS process, occupying an area of 13.62mm2. The measured current consumption of single sensing front-end channel is only 76nA with the noise efficiency factor of 5.82. The measured output signal magnitude is 564.3mVpp with 1% total harmonic distortion.