This work describes the analysis, design and realisation of biomedical amplifiers and analog front-end building blocks implemented in CMOS technology. In this context, a 1.2 V, 130 nm CMOS operational amplifier design is presented which allows to adjust its noise and power specifications. The amplifier and front-end concepts were used in the design of biomedical system-on-chip solutions that include calibration and DC-offset supression techniques.