Combining direct current and kilohertz frequency alternating current to mitigate onset activity during electrical...

Area of Science:

• Bioelectronics
• Neuroscience
• Biomedical Engineering

Background:

• Electrical nerve block is crucial for bioelectronics, with kilohertz frequency alternating current (KHFAC) and direct current (DC) as primary modalities.
• KHFAC presents an onset response limiting clinical use, while DC causes damaging reactive species.
• Advancements in high-capacitance electrodes enable longer DC delivery, but the onset response remains a challenge.

Purpose of the Study:

• To develop and evaluate a novel waveform, the combined reduced onset waveform (CROW), integrating DC and KHFAC.
• To mitigate the neural onset response associated with KHFAC nerve block.
• To enable safe and effective long-duration electrical nerve block for bioelectronic applications.

Main Methods:

• Simulations using the NEURON axonal environment to assess waveform feasibility and mechanism.
• Acute experimental validation in Sprague-Dawley rats to measure onset response mitigation.
• Systematic variation of waveform parameters, focusing on DC pulse amplitude.

Main Results:

• The CROW waveform significantly reduced the onset response both in silico and in vivo.
• Onset response area was decreased by over 90% in acute rat experiments.
• DC pulse amplitude was identified as critical for onset mitigation, requiring 6-8 times the DC block threshold.

Conclusions:

• The CROW waveform effectively minimizes the onset response of KHFAC nerve block.
• This approach holds potential for broader clinical translation of electrical nerve block.
• Optimized DC pre-pulses are key to achieving safe and effective nerve block initiation.