OBJECTIVE: To explore the preparation of nano-silver acupuncture needles and evaluate the appearance, structure and properties. METHODS: Stainless steel acupuncture needles were pretreated by polishing with sandpaper and cleaning with ultrapure water and absolute ethanol. As the working electrodes, the needles were placed in an electrolyte solution contained silver nitrate (AgNO₃), potassium nitrate (KNO₃), and polyvinylpyrrolidone (PVP); and the silver nanoparticles were deposited at a constant voltage of -0.2 V for 1 200 s. The heat-treatment was conducted at 600 ℃ for 15 min in an argon atmosphere to strengthen the adhesion between the nanoparticles and the substrate. The surface appearance and structure of nano-silver acupuncture needles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The electrical conductivity, thermal conductivity and biocompatibility of the needles were evaluated. The cytotoxicity and biocompatibility of the sample were assessed using the CCK-8 assay. According to the national standard, Acupuncture Needles (GB 2024-2016), the other physicochemical performances of nano-silver acupuncture needles were tested. RESULTS: ①By controlling the AgNO₃ concentration and the molar ratio of AgNO₃ to PVP, it was found that at an AgNO₃ concentration of 2 mmol/L and a molar ratio of 5∶1, silver nanoparticles with the diameter of 50-100 nm, regular appearance, and uniform distribution were obtained. At a lower concentration, the size of silver nanoparticles was smaller and unevenly distributed particles, whereas a higher concentration tended to produce a dendritic structure. ②By sandpaper polishing, acid etching pretreatment, and heat-treatment at 600 ℃ under argon for 15 min, the adhesion of silver nanoparticles on the surface of the needle body was strengthened, and the simulated pig skin puncture test showed the intact coating without shedding. ③SEM found that the silver nanoparticles were uniformly deposited, forming a nanofilm approximately 1.5 μm thick; XRD analysis showed the diffraction peaks corresponding to cubic crystal silver (111), (200), (220) and (311); and XPS detected characteristic peaks of Ag 3d3/2 and Ag 3d5/2, confirming the successful deposition and good crystallinity of the silver nanoparticles. ④Resistivity measurements indicated that the nano-silver acupuncture needles exhibited a resistivity of approximately 0.15 Ω·cm, about three times lower than that of unmodified stainless steel needles. The infrared thermography demonstrated that their thermal conductivity was superior to that of traditional acupuncture needles. In vitro CCK-8 cytotoxicity assay showed that the nano-silver acupuncture needles had no adverse effects on human skin fibroblasts and possessed good biocompatibility. ⑤ The key parameters such as needle tip performance, hardness, and the adhesion between the needle body and handle were in compliance with the requirements in Acupuncture Needles (GB 2024-2016), ensuring a quality guarantee provided for clinical applications. CONCLUSION The preparation of nano-silver acupuncture needles effectively overcomes the insufficient toughness of traditional silver needles and improves the electrical and thermal conductivity of stainless acupuncture needles.
Silver/chemistry* ; Needles ; Acupuncture Therapy/instrumentation* ; Metal Nanoparticles/chemistry* ; Humans ; Electric Conductivity ; Animals

Objective: To explore the relationship between liver controlled attenuation parameters (CAP) and body fat mass and its distribution. Methods: From May to December 2018, 978 adult patients visited at the fatty liver center of the Third People's Hospital of Changzhou were treated. The patient's liver controlled attenuation parameters were measured by transient elastography and the body fat mass and its distribution were measured by bioelectrical impedance technology. Pearson’s correlation coefficient was adopted to describe the correlation between liver CAP value and body mass index (BMI), body fat mass index (BFMI), trunk fat mass index (TFMI), limbs fat mass index (LFMI) and visceral fat area (VFA). Receiver operating characteristic curve (ROC) and area under the curve (AUC) were used to evaluate BMI, BFMI, TFMI, LFMI and VFA to differentiate the cut-off points and efficacy of CAP for diagnosing grading of fatty liver changes in S0-1 and S2-3. Results: In 653 cases of male, S0 ~ S3 accounted for 4.90%, 3.37%, 22.36% and 69.37%, respectively, and in 325 cases of females, S0 ~ S3 accounted for 7.38%, 6.46%, 13.23% and 72.92%, respectively. Female patients had more visceral, trunk and limbs fat than male (P < 0.01). Body mass, body fat mass, body fat percentage, BMI, BFMI, TFMI, LFMI, and VFA were increased in male and female patients with increasing liver fat grade (P < 0.01). CAP values ​​of male and female patients were positively correlated with BMI, BFMI, TFMI, LFMI and VFA. Percentage of body fat mass increased with increasing liver fat grade (male: F = 13.42, P < 0.001; female: F = 3.22, P = 0.023); while limb fat mass percentage did not increase with liver fat grade (Male: F = 1.13, P = 0.34; female: F = 1.05, P = 0.37). Hepatic steatosis grading (S0 ~ 1 or S2 ~ 3) diagnosed with CAP were distinguished through BMI, BFMI, TFMI, LFMI and VFA. AUC was 0.80 ~ 0.82 in males (P < 0.01), and 0.75 ~ 0.78 in females (P < 0.01). Conclusion The liver CAP value is positively correlated with the body's limbs, trunk and visceral fat, and has a strong correlation with trunk and visceral fat. BMI, BFMI, TFMI, LFMI and VFA up to some extent can identify the CAP diagnosis of grading of fatty liver changes in S0-1 and S2-3.