Electrochemical corrosion of STS304 acupuncture needles by electrical stimulation

A Battery Method to Enhance the Degradation of Iron Stent and Regulating the Effect on Living Cells

Iron is a promising material for cardiovascular stent applications, however, the low biodegradation rate presents a challenge. Here, a dynamic method to improve the degradation rate of iron and simultaneously deliver electrical energy that could potentially inhibit cell proliferation on the device is reported. It is realized by pairing iron with a biocompatible hydrogel cathode in a cell culture media-based electrolyte forming an iron-air battery. This system does not show cytotoxicity to human adipose-stem cells over a period of 21 days but inhibits cell proliferation. The combination of enhanced iron degradation and inhibited cell proliferation by this dynamic method suggests it might be an approach for restenosis inhibition of biodegradable stents.

Influence of acupuncture needle physical-chemical properties on needling quality

OBJECTIVES

This study analyzed the physical-chemical properties of three different brands of acupuncture needle, classified by acupuncturists as high (A), medium (B) and low (C) quality.

METHODS

Experienced acupuncturists, rated, in terms of perceived needling quality, three acupuncture needle brands as high (A), medium (B) and low (C) quality. Next, scanning electron microscopy (SEM) images of the tip and surface finish of the needles of each brand were analyzed. A mechanical test was developed and performed to evaluate the compressive force required to insert the needles through a smooth surface (silicon). In addition, X-ray fluorescence spectroscopy (XRF) and dispersive energy spectroscopy (DES) were conducted to analyze the material composition of the needles and presence of oxidation.

RESULTS

SEM images revealed that needle brands A and B presented a sharper tip and a more regular surface finish in comparison to brand C. In the insertion test, needle brands A and B had similar performance characteristics, with A requiring less force to penetrate the silicon device when compared to B, while C failed to penetrate the silicon and complete the test. The XRF analysis did not reveal any differences in material composition between the three brands. However, brand C exhibited particles embedded on the needle surface and DES confirmed oxidation.

CONCLUSION

This study demonstrates that perceived needling quality by acupuncturists can be correlated with physical-chemical properties of the needles, especially those related to finishing quality of the tip and the surface of the needles.

Safety analysis of percutaneous needle electrolysis: a study of needle composition, morphology, and electrical resistance

BACKGROUND

Percutaneous needle electrolysis (PNE) consists of a galvanic current combined with the insertion of a solid needle into the tissues of the musculoskeletal system. The application of a galvanic current through a needle can alter the morphology and composition during treatment application. This procedure may also provoke a localized temperature increase.

AIM

The aim was to evaluate the safety of the PNE procedure by analyzing possible alterations of the needles employed.

METHODS

Physio Invasiva^® and AguPunt EPI^® brand needles, commonly used for the application of this technique, were analyzed in response to three different treatment protocols. Temperature changes were evaluated with the needles immersed in a test tube containing Ringer's solution, and electrical resistance was evaluated with a multimeter. The morphology of the needles, pre- and post-treatment, was examined with a scanning electron microscope (FEI Quanta 600), and the composition of the needles was evaluated using RX diffusion with Oxford Instruments software.

RESULTS

Ringer's solution contained in the test tubes examined did not present temperature changes. No changes were observed in the needles under investigation with respect to electrical resistance, morphology, or composition with a protocol applying 3-mA intensity for 3 s and three applications. However, important morphological alterations were observed that affected needle composition after 50 applications (at 3 mA for 3 s).

CONCLUSION

PNE, applied according to conventional protocols, appeared to be safe and athermal, and did not provoke a loss of metal particles or modify the morphology of the needles used when studied in vitro.

Noble metal sensitized invasive porous bioelectrodes: advanced medical device for enhanced neuronal activity and chronic alcohol treatment

Invasive bioelectrodes are widely used as an effective treatment for several acute and chronic diseases. In earlier work using high surface area invasive porous bioelectrodes evaluated in an animal model of alcoholism withdrawal, we demonstrated significantly improved electrophysiological and behavioral responses. In this study, we further modify the surface of these invasive porous bioelectrodes with noble metal (Ag, Au, Pt) nanoparticles. Compared to both conventional and porous bioelectrodes, noble metal sensitized invasive porous bioelectrodes show markedly increased low threshold (LT) and wide dynamic range (WDR) neuronal activity. In particular, Pt-sensitized invasive porous bioelectrodes show the highest WDR neuronal activity only upon insertion. In addition, Ag-sensitized invasive porous bioelectrodes, whose surface area is about 37 times greater than that of conventional bioelectrodes, show improved electrochemical properties with higher LT and WDR neuronal activity when stimulated. In an animal model of chronic alcoholism, using normal and alcohol-treated Sprague-Dawley (SD) rats evaluated with the elevated plus maze (EPM) test, the Ag-sensitized invasive porous bioelectrodes show about 20% higher open arms time. These results suggest that these noble metal-sensitized invasive bioelectrodes may offer improved therapeutic outcomes for the treatment of chronic alcoholism, and given these enhanced electrophysiological properties, for other conditions as well.

Microelectrochemical Smart Needle for Real Time Minimally Invasive Oximetry

A variety of brain disorders such as neural injury, brain dysfunction, vascular malformation, and neurodegenerative diseases are associated with abnormal levels of oxygen. Current methods to directly monitor tissue oxygenation in the brain are expensive and invasive, suffering from a lack of accuracy. Electrochemical detection has been used as an invasiveness and cost-effectiveness method, minimizing pain, discomfort, and injury to the patient. In this work, we developed a minimally invasive needle-sensor with a high surface area to monitor O2 levels in the brain using acupuncture needles. The approach was to directly etch the iron from stainless steel acupuncture needles via a controlled pitting corrosion process, obtaining a high microporous surface area. In order to increase the conductivity and selectivity, we designed and applied for the first time a low-cost coating process using non-toxic chemicals to deposit high surface area carbon nanoparticle, catalytically active laccase, and biocompatible polypyrrole. The physicochemical properties of the materials were characterized as well as their efficacy and viability as probes for the electrochemical detection of PO2. Our modified needles exhibited efficient electrocatalysis and high selectivity toward O2, with excellent repeatability. We well engineered a small diagnostic tool to monitor PO2, minimally invasive, able to monitor real-time O2 in vivo complex environments.

Adverse events related to electroacupuncture: a systematic review of single case studies and case series

OBJECTIVE

Electroacupuncture (EA) is used in the treatment of various diseases through the use of electrical stimulation. Reports of adverse events (AEs) associated with acupuncture are relatively consistent, but the safety of EA has been less well reported. In this systematic review, we provide a summary of the types of AEs related to EA in clinical practice.

METHODS

Twelve electronic databases, including those in English (PubMed, Ovid-EMBASE, CENTRAL), Korean (KMbase, KISS, NDSL, KISTI, OASIS), Chinese (CNKI, Wanfang, Weipu) and Japanese (J-STAGE), were systematically searched for single case studies and case series through April 2018. There were no language restrictions. We included clinical studies in which EA was used as a key intervention and in which AEs that may have been causally related to EA were reported.

RESULTS

Thirty-seven studies, including 27 single case studies and 10 case series, were evaluated. The most frequently reported AEs were pallor (eight cases), skin pigmentation (eight cases), vertigo (seven cases), chest tightness (six cases), vomiting (six cases) and unconsciousness (five cases). Thirty-one cases (62%) achieved full recovery and three cases (6%) achieved partial recovery. There were also three cases of death (6%).

CONCLUSION

AEs related to EA included acupuncture-related AEs and serious AEs induced by electrical stimulation. Currently, specific stimulation conditions associated with EA-specific AEs are not identifiable due to inappropriate reporting. However, skin pigmentation, syncope or spasm, implantable cardioverter-defibrillator shock, cardiac emergencies, electrical burns, and potential internal organ injury are potential EA-specific AEs regarding which physicians should be cautious in clinical practice.

Evaluation of a conducting elastomeric composite material for intramuscular electrode application

Electrical stimulation of the muscle has been proven efficacious in preventing atrophy and/or reanimating paralyzed muscles. Intramuscular electrodes made from metals have significantly higher Young's Moduli than the muscle tissues, which has the potential to cause chronic inflammation and decrease device performance. Here, we present an intramuscular electrode made from an elastomeric conducting polymer composite consisting of PEDOT-PEG copolymer, silicone and carbon nanotubes (CNT) with fluorosilicone insulation. The electrode wire has a Young's modulus of 804 (±99) kPa, which better mimics the muscle tissue modulus than conventional stainless steel (SS) electrodes. Additionally, the non-metallic composition enables metal-artifact free CT and MR imaging. These soft wire (SW) electrodes present comparable electrical impedance to SS electrodes of similar geometric surface area, activate muscle at a lower threshold, and maintain stable electrical properties in vivo up to 4 weeks. Histologically, the SW electrodes elicited significantly less fibrotic encapsulation and less IBA-1 positive macrophage accumulation than the SS electrodes at one and three months. Further phenotyping the macrophages with the iNOS (pro-inflammatory) and ARG-1 (pro-healing) markers revealed significantly less presence of pro-inflammatory macrophage around SW implants at one month. By three months, there was a significant increase in pro-healing macrophages (ARG-1) around the SW implants but not around the SS implants. Furthermore, a larger number of AchR clusters closer to SW implants were found at both time points compared to SS implants. These results suggest that a softer implant encourages a more intimate and healthier electrode-tissue interface. STATEMENT OF SIGNIFICANCE: Intramuscular electrodes made from metals have significantly higher Young's Moduli than the muscle tissues, which has the potential to cause chronic inflammation and decrease device performance. Here, we present an intramuscular electrode made from an elastomeric conducting polymer composite consisting of PEDOT-PEG copolymer, silicone and carbon nanotubes with fluorosilicone insulation. This elastomeric composite results in an electrode wire with a Young's modulus mimicking that of the muscle tissue, which elicits significantly less foreign body response compared to stainless steel wires. The lack of metal in this composite also enables metal-artifact free MRI and CT imaging.

Biological safety of Electroacupuncture with STS316 needles

Background

Electroacupuncture (EA) is often used in clinical settings due to its analgesic effect, but its safety has not been verified due to the lack of clear criteria. This study examined the critical range of the corrosion of stainless steel types STS304 and STS316, which have been used clinically, and the relationship between needle corrosion and cell necrosis.

Method

The critical point of corrosion for STS304 and STS316 was identified by varying the time, frequency, and stimulation intensity. In a tissue necrosis experiment, EA stimulation was applied to rats using STS316 needles with different thicknesses at maximum intensity for 60 min, and the presence of corrosion and tissue necrosis was determined. A cytotoxicity experiment was also conducted and assessed the needles and tissue necrosis.

Results

The results showed that STS316 was more stable than STS304 and that only coated needles corroded. Furthermore, tissue necrosis was observed regardless of corrosion, and slight cell necrosis was associated with needles with corrosion.

Conclusions

This study demonstrated that non-coated STS316 was the most stable for EA stimulation and that corrosion byproducts and cell necrosis were not directly related.

Examination of needle surface corrosion in electroacupuncture

BACKGROUND

Electroacupuncture (EA) is a modern form of acupuncture therapy where stainless steel acupuncture needles are used as percutaneous electrodes to apply electrical stimulation. The concern about electrolytic corrosion of needles during EA has not been conclusively addressed.

AIM

To examine whether corrosion of stainless steel acupuncture needles occurs after EA to establish the safety profile of this therapy.

METHODS

The study comprised four EA sessions on healthy participants mimicking a common clinical practice, with needle surface examinations conducted immediately after each session. Used acupuncture needles that did not undergo electrical stimulation and unused needles taken from the original package were also examined as control comparisons. Two commonly used types of single-use, silicone-coated, stainless steel needles were selected for the experiment. The ES-160 digital acupunctoscope (a charge-balanced electric stimulator) was used to deliver electrical stimulation, and an oscilloscope was used to record the waveforms and electric currents. All needles were sterilised before examination by a scanning electron microscope (SEM), where images of needle tips and shafts were taken for further analysis.

RESULTS AND CONCLUSIONS

32 needles were examined under the SEM. As the main findings, the SEM images showed the surface finish, burr attachments and surface characteristics of needle samples. No evidence of electrolytic corrosion was detected on any needle that underwent electrical stimulation for 30 min delivered by a charge-balanced acupunctoscope in healthy participants. The choice of a charge-balanced acupunctoscope is recommended to avoid any potential corrosion of needles in EA clinical practice.