An active electrode for biopotential recording from small localized bio-sources

Area of Science:

• Biomedical Engineering
• Medical Acupuncture
• Biopotential Measurement

Background:

• Laser bio-stimulation in Medical Acupuncture lacks objective scientific proof.
• Distinguishing laser effects from placebo requires reliable biopotential recordings.
• Previous methods struggled with objective evidence for laser acupuncture efficacy.

Purpose of the Study:

• To design and construct an active electrode and amplifier for biopotential recording from acupuncture points.
• To investigate laser-induced potentials from small localized bio-sources (SLB).
• To provide objective evidence for the bio-stimulation effects of lasers in Medical Acupuncture.

Main Methods:

• Developed an active electrode with an adjustable anchoring system to minimize electrode-skin impedance and motion artifacts.
• Incorporated amplifier front-end operational amplifiers within the electrode to reduce noise and component count.
• Utilized two selectable amplifier modes (semi-AC and AC) with a bandwidth up to 1000 Hz.

Main Results:

• Achieved an average DC electrode-skin contact impedance of 450 kOmega on unprepared skin.
• Measured low output noise (10 mVp-p) and high common-mode rejection ratio (96 dB at 50 Hz).
• Successfully recorded high-quality small localized bio-source (SLB) signals after laser stimulation without skin preparation or electrolyte gel.

Conclusions:

• The new active electrode significantly reduces skin impedance, variation, and motion artifacts.
• High-quality SLB signals can be recorded without skin preparation, supporting objective proof of laser bio-stimulation.
• The design offers low noise, reduced size, and lower power consumption compared to existing systems.