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

OBJECTIVES: To investigate the efficacy of Ag₂Se nanoparticles for eliminating intracellular Porphyromonas gingivalis (P. gingivalis) in esophageal cancer and examine the effect of P. gingivalis clearance on progression of esophageal cancer. METHODS: Ag₂Se nanoparticles were synthesized via a chemical synthesis method. The effects of Ag₂Se nanoparticles on P. gingivalis viability and colony-forming ability were assessed using fluorescence staining and colony formation assays. In a mouse model bearing subcutaneous murine esophageal cancer cell allograft with P. gingivalis infection, the effect of treatment with Ag₂Se nanoparticles on the abundance of P. gingivalis in the tumor tissues was quantified using RNAscope in situ hybridization and quantitative polymerase chain reaction (qPCR), and the changes in tumor volume were monitored. The biosafety of Ag₂Se nanoparticles was assessed by examining liver and kidney functions and pathological changes in the major organs of the mice. RESULTS: Transmission electron microscopy revealed that the synthesized Ag₂Se nanoparticles were uniformly dispersed spherical particles with a diameter around 50 nm. In vitro experiments demonstrated that exposure to Ag₂Se nanoparticles significantly reduced the viability and clonal proliferation capacity of P. gingivalis in a dose-dependent manner. In the tumor-bearing mice, treatment with Ag₂Se nanoparticles significantly reduced the abundance of P. gingivalis in tumor tissues and suppressed tumor cell proliferation. No significant damages to the liver and kidney functions or the major organs were observed in Ag₂Se nanoparticle-treated mice, demonstrating good biocompatibility of Ag₂Se nanoparticles. CONCLUSIONS Ag₂Se nanoparticles exhibit significant bactericidal and inhibitory effects against P. gingivalis, and can effectively eliminate intracellular P. gingivalis to suppress the growth of esophageal cancer allograft in mice, suggesting the potential of Ag₂Se nanoparticles in the treatment of esophageal cancer.
Animals ; Porphyromonas gingivalis/drug effects* ; Mice ; Esophageal Neoplasms/pathology* ; Nanoparticles ; Metal Nanoparticles ; Bacteroidaceae Infections ; Cell Line, Tumor

Tongue squamous cell carcinoma (TSCC) is a prevalent malignancy that afflicts the head and neck area and presents a high incidence of metastasis and invasion. Accurate diagnosis and effective treatment are essential for enhancing the quality of life and the survival rates of TSCC patients. The current treatment modalities for TSCC frequently suffer from a lack of specificity and efficacy. Nanoparticles with diagnostic and photothermal therapeutic properties may offer a new approach for the targeted therapy of TSCC. However, inadequate accumulation of photosensitizers at the tumor site diminishes the efficacy of photothermal therapy (PTT). This study modified gold nanodots (AuNDs) with the TSCC-targeting peptide HN-1 to improve the selectivity and therapeutic effects of PTT. The Au-HN-1 nanosystem effectively targeted the TSCC cells and was rapidly delivered to the tumor tissues compared to the AuNDs. The enhanced accumulation of photosensitizing agents at tumor sites achieved significant PTT effects in a mouse model of TSCC. Moreover, owing to its stable long-term fluorescence and high X-ray attenuation coefficient, the Au-HN-1 nanosystem can be used for fluorescence and computed tomography imaging of TSCC, rendering it useful for early tumor detection and accurate delineation of surgical margins. In conclusion, Au-HN-1 represents a promising nanomedicine for imaging-based diagnosis and targeted PTT of TSCC.
Tongue Neoplasms/diagnostic imaging* ; Carcinoma, Squamous Cell/diagnostic imaging* ; Animals ; Gold/chemistry* ; Mice ; Photothermal Therapy/methods* ; Tomography, X-Ray Computed ; Photosensitizing Agents ; Metal Nanoparticles ; Humans ; Cell Line, Tumor

Biosynthesized selenium nanoparticles (SeNPs) have attracted much attention because of their unique physical, chemical, and biological properties. The microbial reduction of selenium salts to SeNPs has great potential, while there is a lack of elite strains. In this study, we explored the reduction of Na₂SeO₃ by Streptomyces avermitilis into SeNPs. The colonies and hyphae of the strain and the synthesized SeNPs were characterized by optical microscopy, scanning electron microscopy (SEM), transmission electron microscope (TEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). At the same time, the inhibitory activity of SeNPs on Fusarium oxysporum, the main pathogen causing root rot of Lycium barbarum, was studied. The results showed that S. avermitilis converted Na₂SeO₃ into SeNPs and tolerated 300 mmol/L Na₂SeO₃, demonstrating strong tolerance. S. avermitilis synthesized spherical SeNPs in the cytoplasm, and most of SeNPs had a diameter of about 100 nm and were released by hyphal fracture. The SeNPs synthesized by S. avermitilis were amorphous, and their surfaces were dominated by C and Se, with the existence of O, N and other elements. SeNPs had functional groups such as -OH, C=O, C-N, and C-H, which were closely related to the stability and biological activity of SeNPs. The SeNPs synthesized by S. avermitilis showcased significant inhibitory activity on F. oxysporum, and 25.0 μmol/mL SeNPs showcased the inhibition rate of 77.61% and EC₅₀ of 0.556 μmol/mL. In conclusion, S. avermitilis can tolerate high Na₂SeO₃ stress and mediate the synthesis of SeNPs. The synthesized SeNPs have good stability and strong inhibitory activity, demonstrating the potential application value in the preparation of SeNPs and the control of L. barbarum root rot.
Streptomyces/metabolism* ; Fusarium/drug effects* ; Lycium/microbiology* ; Selenium/metabolism* ; Nanoparticles/chemistry* ; Plant Diseases/microbiology* ; Metal Nanoparticles/chemistry* ; Antifungal Agents/pharmacology*

The rapid growth of electronic waste has led to the accumulation of large amounts of valuable metal elements in the environment, causing serious environmental pollution and resource wastage. Compared with pyrometallurgical and hydrometallurgical processes which often result in severe environmental pollution and carbon footprints, microbial synthesis of metal nanoparticles has emerged as a green and environmentally friendly metallurgical technology for recovering valuable metals from electronic waste. This paper first reviews the mechanisms of metal nanoparticle synthesis within different structural compartments of microbial cells. It then introduces the applications of microbially synthesized metal nanoparticles in fields such as environmental remediation, energy production, biocatalysis, and biomedicine. Finally, it discusses the development prospects of microbial synthesis of metal nanoparticles, including exploration of diverse microbial resources and synthesis pathways, yield enhancement, integration of new technologies, and industrialization, aiming to promote further research and application of microbial synthesis of metal nanoparticles.
Metal Nanoparticles/chemistry* ; Bacteria/metabolism*

Silver nanoparticles (AgNPs) is known as one of the most valuable metal nanoparticles in antibacterial and anticancer application. AgNPs-resistant bacteria has been documented, but it is unclear whether cancer cells can also escape the anti-cancer effect of AgNPs. In this study, we aimed to investigate this phenomenon and its underlying mechanism. The antibacterial activity and cytotoxicity of AgNPs were measured in the presence of HeLa cell metabolites. The status of AgNPs in the system associated with metabolites were characterized by UV-Vis, Zetasizer Nano ZS, and transmission electron microscopy. Non-targeted metabolomics was used to reveal the metabolites components that bind with AgNPs. HeLa cells were injected intraperitoneally to establish the tumor-bearing mice model, and the stability of AgNPs in mice serum was analyzed. The results manifested that HeLa cell metabolites inhibited the anticancer and antibacterial effects of AgNPs in a dose-dependent manner by causing AgNPs aggregation. Effective metabolites that inhibited the biological activity of AgNPs were stable in 100 ℃, insoluble in chloroform, containing sulfur elements, and had a molecular weight less than 1 kDa in molecular weight. There were 115 compounds bound with AgNPs. In vitro experiments showed that AgNPs aggregation occurred only when the concentration of α-ketoglutarate (AKG) and glutathione (GSH) together reached a certain threshold. Interestingly, the concentration of AKG and GSH in HeLa cellular metabolites was 10 and 6 times higher than that in normal cervical epithelial cells, respectively, which explained why the threshold was reached. Furthermore, the stability of AgNPs in the serum of tumor-bearing mice decreased by 20% (P < 0.05) compared with the healthy mice. In conclusion, our study demonstrates that HeLa cells escaped the anti-cancer effect of AgNPs through the synergistic effect of AKG and GSH, suggesting the need to develop strategies to overcome this limitation.
Humans ; Animals ; Mice ; HeLa Cells ; Silver/pharmacology* ; Ketoglutaric Acids/pharmacology* ; Metal Nanoparticles ; Anti-Bacterial Agents/pharmacology* ; Glutathione ; Microbial Sensitivity Tests

OBJECTIVE: Late 2019 witnessed the outbreak and widespread transmission of coronavirus disease 2019 (COVID-19), a new, highly contagious disease caused by novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Consequently, considerable attention has been paid to the development of new diagnostic tools for the early detection of SARS-CoV-2. METHODS: In this study, a new poly-N-isopropylacrylamide microgel-based electrochemical sensor was explored to detect the SARS-CoV-2 spike protein (S protein) in human saliva. The microgel was composed of a copolymer of N-isopropylacrylamide and acrylic acid, and gold nanoparticles were encapsulated within the microgel through facile and economical fabrication. The electrochemical performance of the sensor was evaluated through differential pulse voltammetry. RESULTS: Under optimal experimental conditions, the linear range of the sensor was 10 ^-13-10 ^-9 mg/mL, whereas the detection limit was 9.55 fg/mL. Furthermore, the S protein was instilled in artificial saliva as the infected human saliva model, and the sensing platform showed satisfactory detection capability. CONCLUSION The sensing platform exhibited excellent specificity and sensitivity in detecting spike protein, indicating its potential application for the time-saving and inexpensive detection of SARS-CoV-2.
Humans ; Microgels ; Spike Glycoprotein, Coronavirus ; COVID-19/diagnosis* ; Gold ; Metal Nanoparticles ; SARS-CoV-2

The wide use of ZnO and CuO nanoparticles in research, medicine, industry, and other fields has raised concerns about their biosafety. It is therefore unavoidable to be discharged into the sewage treatment system. Due to the unique physical and chemical properties of ZnO NPs and CuO NPs, it may be toxic to the members of the microbial community and their growth and metabolism, which in turn affects the stable operation of sewage nitrogen removal. This study summarizes the toxicity mechanism of two typical metal oxide nanoparticles (ZnO NPs and CuO NPs) to nitrogen removal microorganisms in sewage treatment systems. Furthermore, the factors affecting the cytotoxicity of metal oxide nanoparticles (MONPs) are summarized. This review aims to provide a theoretical basis and support for the future mitigating and emergent treatment of the adverse effects of nanoparticles on sewage treatment systems.
Wastewater/toxicity* ; Sewage/chemistry* ; Zinc Oxide/chemistry* ; Waste Disposal, Fluid ; Nanoparticles/chemistry* ; Metal Nanoparticles/chemistry* ; Nitrogen/metabolism* ; Water Purification

Objective: To investigate the effects and mechanism of interleukin-4-modified gold nanoparticle (IL-4-AuNP) on the wound healing of full-thickness skin defects in diabetic mice. Methods: Experimental research methods were adopted. Gold nanoparticle (AuNP) and IL-4-AuNP were synthesized by improving the methods described in published literature. The morphology of those two particles were photographed by transmission electron microscopy, and their particle sizes were calculated. The surface potential and hydration particle size of the two particles were detected by nanoparticle potentiometer and particle size analyzer, respectively. The clearance rate of IL-4-AuNP to hydrogen peroxide and superoxide anion was measured by hydrogen peroxide and superoxide anion kits, respectively. Mouse fibroblast line 3T3 cells were used and divided into the following groups by the random number table (the same below): blank control group, hydrogen peroxide alone group treated with hydrogen peroxide only, hydrogen peroxide+IL-4-AuNP group treated with IL-4-AuNP for 0.5 h and then treated with hydrogen peroxide. After 24 h of culture, the reactive oxygen species (ROS) levels of cells were detected by immunofluorescence method; cell count kit 8 was used to detect relative cell survival rate. The macrophage Raw264.7 mouse cells were then used and divided into blank control group and IL-4-AuNP group that treated with IL-4-AuNP. After 24 h of culture, the expression of arginase 1 (Arg-1) in cells was observed by immunofluorescence method. Twelve male BALB/c mice (mouse age, sex, and strain, the same below) aged 8 to 10 weeks were divided into IL-4-AuNP group and blank control group, treated accordingly. On the 16^th day of treatment, whole blood samples were collected from mice for analysis of white blood cell count (WBC), red blood cell count (RBC), hemoglobin level, or platelet count and the level of aspartate aminotransferase (AST), alanine transaminase (ALT), urea, or creatinine. The inflammation, bleeding, or necrosis in the heart, liver, spleen, lung, and kidney tissue of mice were detected by hematoxylin-eosin (HE). Another 36 mice were selected to make diabetic model, and the full-thickness skin defect wounds were made on the back of these mice. The wounds were divided into blank control group, AuNP alone group, and IL-4-AuNP group, with 12 mice in each group, and treated accordingly. On the 0 (immediately), 4^th, 9^th, and 15^th day of treatment, the wound condition was observed and the wound area was calculated. On the 9^th day of treatment, HE staining was used to detect the length of neonatal epithelium and the thickness of granulation tissue in the wound. On the 15^th day of treatment, immunofluorescence method was used to detect ROS level and the number of Arg-1 positive cells in the wound tissue. The number of samples was 6 in all cases. Data were statistically analyzed with independent sample t test, corrected t test, Tukey test, or Dunnett T3 test. Results: The size of prepared AuNP and IL-4-AuNP were uniform. The particle size, surface potential, and hydration particle size of AuNP and IL-4-AuNP were (13.0±2.1) and (13.9±2.5) nm, (-45.8±3.2) and (-20.3±2.2) mV, (14±3) and (16±4) nm, respectively. For IL-4-AuNP, the clearance rate to hydrogen peroxide and superoxide anion were (69±4)% and (52±5)%, respectively. After 24 h of culture, the ROS level of 3T3 in hydrogen peroxide alone group was significantly higher than that in blank control group (q=26.12, P<0.05); the ROS level of hydrogen peroxide+IL-4-AuNP group was significantly lower than that in hydrogen peroxide alone group (q=25.12, P<0.05) and close to that in blank control group (P>0.05). After 24 h of culture, the relative survival rate of 3T3 cells in hydrogen peroxide+IL-4-AuNP group was significantly higher than that in hydrogen peroxide alone group (t=51.44, P<0.05). After 24 h of culture, Arg-1 expression of Raw264.7 cells in IL-4-AuNP group was significantly higher than that in blank control group (t'=8.83, P<0.05).On the 16^th day of treatment, there were no significant statistically differences in WBC, RBC, hemoglobin level, or platelet count and the level of AST, ALT, urea, or creatinine of mice between blank control group and IL-4-AuNP group (P>0.05). No obvious inflammation, bleeding or necrosis was observed in the heart, liver, spleen, lung, and kidney of important organs in IL-4-AuNP group, and no significant changes were observed compared with blank control group. On the 0 and 4^th day of treatment, the wound area of diabetic mice in blank control group, AuNP alone group, and IL-4-AuNP group had no significant difference (P>0.05). On the 9^th day of treatment, the wound areas both in AuNP alone group and IL-4-AuNP group were significantly smaller than that in blank control group (with q values of 9.45 and 14.87, respectively, P<0.05), the wound area in IL-4-AuNP group was significantly smaller than that in AuNP alone group (q=5.42, P<0.05). On the 15^th day of treatment, the wound areas both in AuNP alone group and IL-4-AuNP group were significantly smaller than that in blank control group (with q values of 4.84 and 20.64, respectively, P<0.05), the wound area in IL-4-AuNP group was significantly smaller than that in AuNP alone group (q=15.80, P<0.05); moreover, inflammations such as redness and swelling were significantly reduced in IL-4-AuNP group compared with the other two groups. On the 9^th day of treatment, compared with blank control group and AuNP alone group, the length of neonatal epithelium in the wound of diabetic mice in IL-4-AuNP group was significantly longer (all P<0.05), and the thickness of the granulation tissue in the wound was significantly increased (with q values of 11.33 and 9.65, respectively, all P<0.05). On the 15^th day of treatment, compared with blank control group, ROS levels in wound tissue of diabetic mice in AuNP alone group and IL-4-AuNP group were significantly decreased (P<0.05). On the 15^th day of treatment, the number of Arg-1 positive cells in the wounds of diabetic mice in IL-4-AuNP group was significantly more than that in blank control group and AuNP alone group, respectively (all P<0.05). Conclusions: IL-4-AuNP is safe in vivo, and can improve the oxidative microenvironment by removing ROS and induce macrophage polarization towards M2 phenotype, thus promote efficient diabetic wound healing and regeneration of full-thickness skin defects in diabetic mice.
Mice ; Male ; Animals ; Interleukin-4 ; Gold/pharmacology* ; Diabetes Mellitus, Experimental ; Creatinine ; Hydrogen Peroxide ; Reactive Oxygen Species ; Superoxides ; Metal Nanoparticles ; Soft Tissue Injuries ; Antibodies ; Inflammation ; Necrosis ; Hemoglobins

Objective: To explore the effects of three-dimensional (3D) bioprinting gelatin methacrylamide (GelMA) hydrogel loaded with nano silver on full-thickness skin defect wounds in rats. Methods: The experimental research method was adopted. The morphology, particle diameter, and distribution of silver nanoparticles in nano silver solution with different mass concentrations and the pore structure of silver-containing GelMA hydrogel with different final mass fractions of GelMA were observed by scanning electron microscope and the pore size was calculated. On treatment day 1, 3, 7, and 14, the concentration of nano silver released from the hydrogel containing GelMA with final mass fraction of 15% and nano silver with final mass concentration of 10 mg/L was detected by mass spectrometer. At 24 h of culture, the diameters of inhibition zone of GelMA hydrogel containing final mass concentration of 0 (no nano silver), 25, 50, and 100 mg/L nano silver against Staphylococcus aureus and Escherichia coli were detected. Fibroblasts (Fbs) and adipose stem cells (ASCs) were isolated respectively by enzymatic digestion using the discarded prepuce after circumcision from a 5-year-old healthy boy who was treated in the Department of Urology of the Second Affiliated Hospital of Zhejiang University School of Medicine in July 2020, and the discarded fat tissue after liposuction from a 23-year-old healthy woman who was treated in the Department of Plastic Surgery of the Hospital in July 2020. The Fbs were divided into blank control group (culture medium only), 2 mg/L nano sliver group, 5 mg/L nano sliver group, 10 mg/L nano sliver group, 25 mg/L nano sliver group, and 50 mg/L nano sliver group, which were added with the corresponding final mass concentrations of nano sliver solution, respectively. At 48 h of culture, the Fb proliferation viability was detected by cell counting kit 8 method. The Fbs were divided into 0 mg/L silver-containing GelMA hydrogel group, 10 mg/L silver-containing GelMA hydrogel group, 50 mg/L silver-containing GelMA hydrogel group, and 100 mg/L silver-containing GelMA hydrogel group and then were correspondingly treated. On culture day 1, 3, and 7, the Fb proliferation viability was detected as before. The ASCs were mixed into GelMA hydrogel and divided into 3D bioprinting group and non-printing group. On culture day 1, 3, and 7, the ASC proliferation viability was detected as before and cell growth was observed by live/dead cell fluorescence staining. The sample numbers in the above experiments were all 3. Four full-thickness skin defect wounds were produced on the back of 18 male Sprague-Dawley rats aged 4 to 6 weeks. The wounds were divided into hydrogel alone group, hydrogel/nano sliver group, hydrogel scaffold/nano sliver group, and hydrogel scaffold/nano sliver/ASC group, and transplanted with the corresponding scaffolds, respectively. On post injury day (PID) 4, 7, 14, and 21, the wound healing was observed and the wound healing rate was calculated (n=6). On PID 7 and 14, histopathological changes of wounds were observed by hematoxylin eosin staining (n=6). On PID 21, collagen deposition of wounds was observed by Masson staining (n=3). Data were statistically analyzed with one-way analysis of variance, analysis of variance for repeated measurement, Bonferroni correction, and independent sample t test. Results: The sliver nano particles in nano silver solution with different mass concentrations were all round, in scattered distribution and uniform in size. The silver-containing GelMA hydrogels with different final mass fractions of GelMA all showed pore structures of different sizes and interconnections. The pore size of silver-containing GelMA hydrogel with 10% final mass fraction was significantly larger than that of silver-containing GelMA hydrogels with 15% and 20% final mass fractions (with P values both below 0.05). On treatment day 1, 3, and 7, the concentration of nano silver released from silver-containing GelMA hydrogel in vitro showed a relatively flat trend. On treatment day 14, the concentration of released nano silver in vitro increased rapidly. At 24 h of culture, the diameters of inhibition zone of GelMA hydrogel containing 0, 25, 50, and 100 mg/L nano silver against Staphylococcus aureus and Escherichia coli were 0, 0, 0.7, and 2.1 mm and 0, 1.4, 3.2, and 3.3 mm, respectively. At 48 h of culture, the proliferation activity of Fbs in 2 mg/L nano silver group and 5 mg/L nano silver group was both significantly higher than that in blank control group (P<0.05), and the proliferation activity of Fbs in 10 mg/L nano silver group, 25 mg/L nano silver group, and 50 mg/L nano silver group was all significantly lower than that in blank control group (P<0.05). Compared with the that of Fbs in 0 mg/L silver-containing GelMA hydrogel group, the proliferation activity of Fbs in 50 mg/L silver-containing GelMA hydrogel group and 100 mg/L silver-containing GelMA hydrogel group was all significantly decreased on culture day 1 (P<0.05); the proliferation activity of Fbs in 50 mg/L silver-containing GelMA hydrogel group was significantly increased (P<0.05), while the proliferation activity of Fbs in 100 mg/L silver-containing GelMA hydrogel group was significantly decreased on culture day 3 (P<0.05); the proliferation activity of Fbs in 100 mg/L silver-containing GelMA hydrogel group was significantly decreased on culture day 7 (P<0.05). The proliferation activity of ASCs in 3D bioprinting group show no statistically significant differences to that in non-printing group on culture day 1 (P>0.05). The proliferation activity of ASCs in 3D bioprinting group was significantly higher than that in non-printing group on culture day 3 and 7 (with t values of 21.50 and 12.95, respectively, P<0.05). On culture day 1, the number of dead ASCs in 3D bioprinting group was slightly more than that in non-printing group. On culture day 3 and 5, the majority of ASCs in 3D bioprinting group and non-printing group were living cells. On PID 4, the wounds of rats in hydrogel alone group and hydrogel/nano sliver group had more exudation, and the wounds of rats in hydrogel scaffold/nano sliver group and hydrogel scaffold/nano sliver/ASC group were dry without obvious signs of infection. On PID 7, there was still a small amount of exudation on the wounds of rats in hydrogel alone group and hydrogel/nano sliver group, while the wounds of rats in hydrogel scaffold/nano sliver group and hydrogel scaffold/nano sliver/ASC group were dry and scabbed. On PID 14, the hydrogels on the wound surface of rats in the four groups all fell off. On PID 21, a small area of wounds remained unhealed in hydrogel alone group. On PID 4 and 7, the wound healing rates of rats in hydrogel scaffold/nano sliver/ASC group were significantly higher than those of the other three groups (P<0.05). On PID 14, the wound healing rate of rats in hydrogel scaffold/nano sliver/ASC group was significantly higher than the wound healing rates in hydrogel alone group and hydrogel/nano sliver group (all P<0.05). On PID 21, the wound healing rate of rats in hydrogel alone group was significantly lower than that in hydrogel scaffold/nano sliver/ASC group (P<0.05). On PID 7, the hydrogels on the wound surface of rats in the four groups remained in place; on PID 14, the hydrogel in hydrogel alone group was separated from the wounds of rats, while some hydrogels still existed in the new tissue of the wounds of rats in the other three groups. On PID 21, the collagen arrangement in the wounds of rats in hydrogel alone group was out of order, while the collagen arrangement in the wounds of rats in hydrogel/nano sliver group, and hydrogel scaffold/nano sliver/ASC group was relatively orderly. Conclusions: Silver-containing GelMA hydrogel has good biocompatibility and antibacterial properties. Its three-dimensional bioprinted double-layer structure can better integrate with new formed tissue in the full-thickness skin defect wounds in rats and promote wound healing.
Male ; Rats ; Animals ; Humans ; Hydrogels/pharmacology* ; Bioprinting ; Metal Nanoparticles ; Rats, Sprague-Dawley ; Silver/pharmacology* ; Soft Tissue Injuries ; Anti-Bacterial Agents