This paper reports on an innovative circuit scheme for process-invariant biasing, which works based on a regenerative current steering mechanism. Named as the current translation and mirroring (Current TRAM) scheme, the proposed circuit is capable of providing bias currents established using the current copying ratios of two complementary current mirrors. Then, the circuit is evolved into a voltage-to-current (V/I) converter, allowing for highly-linear control of the bias current using an input control voltage. The proposed V/I converter is then used in a cross-coupled structure in order to design a fully-integrated pseudo-differential operational transconductance amplifier (OTA) circuit with a linearly-tunable transconductance. This OTA is dedicated to the integrated circuit-sensor systems where the analog processing (e.g., filtering) of signals with extremely low cut-off frequencies (such as in bioelectronic sensor interfaces) is required. Designed in a standard 0.13 nm CMOS process, the proposed OTA exhibits a transconductance tunable within the range of 0.39 ~ 0.69 nA/V with a maximum total harmonic distortion of 1%. The circuit dissipated 5 nW at a supply voltage of 1.0 V.