https://orcid.org/0000-0003-2069-2422
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Abstract
Background
Single to multiple pulse packs of bipolar, alternating current radiofrequency (RF) oscillations have been used for various medical purposes using invasive microneedle electrodes. This study was designed to evaluate the effects of pulse widths and cycles of RF pulse packs on immediate and delayed thermal tissue reactions in in vivo rat skin.
Methods
RF energy at the frequency of 1 MHz and power of 70 W was delivered at each experimental setting into in vivo rat skin at 1.5-mm microneedle penetration, and then, tissue samples were obtained after 1 h and 3, 7, 14, and 21 days and histologically analyzed.
Results
A single-pulse-pack RF treatment generated coagulative necrosis zones in the dermal peri-electrode area and zones of non-necrotic thermal reactions in the dermal inter-electrode area. Multiple pulse-pack, RF-treated rat skin specimens revealed that the number and size of peri-electrode coagulative necrosis were markedly decreased by increasing the number of pulse packs and accordingly decreasing the conduction time of each pulse pack. The microscopic changes in RF-induced non-necrotic thermal reaction in the inter-electrode area were more remarkable in specimens treated with RF of 7 or 10 pulse packs than in specimens treated with RF of 1–4 pulse packs.
Conclusion
The gated delivery of multiple RF pulse packs using a bipolar, alternating current, 1-MHz RF system using insulated microneedle electrodes efficiently generates non-necrotic thermal tissue reactions over the upper, mid, and deep dermis and subcutaneous fat in the inter-electrode areas.
Data Sharing Statement
The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.
Statement of Ethics
All experimental protocols were approved by the Ethics Committee of the Soonchunhyang University Institutional Animal Care and Use Committee (Cheonan, Korea).
Acknowledgments
We would like to thank Sunny Kang (Shenb Co., Ltd., Seoul, Korea), Min Choi (Shenb Co., Ltd.), and Bora Kim (Shenb Co., Ltd.) for their technical support.
Author Contributions
All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.
Disclosure
The authors declare no conflicts of interest in this work.