Self-Assembly Strategy for Constructing Porous Boron and Nitrogen Co-Doped Carbon as an Efficient ORR Electrocatalyst toward Zinc-Air Battery.

Carbon nanomaterials doped with N and B could activate nearby carbon atoms to promote charge polarization through the synergistic coupling effect between N and B atoms, thus facilitating adsorption of O2 and weakening O-O bond to enhance oxygen reduction reaction. Herein, a simple and controllable self-assembly strategy is applied to synthesize porous B, N co-doped carbon-based catalysts (BCN-P), which employs the macrocyclic molecule cucurbit[7]uril (CB7) as nitrogen source, and 3D aromatic-like closo-[B12H12]2- as boron source. In addition, polystyrene microspheres are added to help introduce porous structure to expose more active sites. Benefitting from porous structures and the synergistic coupling effect between N and B atoms, BCN-P has a high onset potential (Eonset=0.846 V) and half-wave potential (E1/2=0.74 V) in alkaline media. The zinc-air battery assembled with BCN-P shows high operating voltage (1.42 V), peak power density (128.7 mW cm-2) and stable charge/discharge cycles, which is even comparable with Pt/C.

Biofilm Homeostasis Interference Therapy via 1 O2 -Sensitized Hyperthermia and Immune Microenvironment Re-Rousing for Biofilm-Associated Infections Elimination.

The recurrence of biofilm-associated infections (BAIs) remains high after implant-associated surgery. Biofilms on the implant surface reportedly shelter bacteria from antibiotics and evade innate immune defenses. Moreover, little is currently known about eliminating residual bacteria that can induce biofilm reinfection. Herein, novel "interference-regulation strategy" based on bovine serum albumin-iridium oxide nanoparticles (BIONPs) as biofilm homeostasis interrupter and immunomodulator via singlet oxygen (1 O2 )-sensitized mild hyperthermia for combating BAIs is reported. The catalase-like BIONPs convert abundant H2 O2 inside the biofilm-microenvironment (BME) to sufficient oxygen gas (O2 ), which can efficiently enhance the generation of 1 O2 under near-infrared irradiation. The 1 O2 -induced biofilm homeostasis disturbance (e.g., sigB, groEL, agr-A, icaD, eDNA) can disrupt the sophisticated defense system of biofilm, further enhancing the sensitivity of biofilms to mild hyperthermia. Moreover, the mild hyperthermia-induced bacterial membrane disintegration results in protein leakage and 1 O2 penetration to kill bacteria inside the biofilm. Subsequently, BIONPs-induced immunosuppressive microenvironment re-rousing successfully re-polarizes macrophages to pro-inflammatory M1 phenotype in vivo to devour residual biofilm and prevent biofilm reconstruction. Collectively, this 1 O2 -sensitized mild hyperthermia can yield great refractory BAIs treatment via biofilm homeostasis interference, mild-hyperthermia, and immunotherapy, providing a novel and effective anti-biofilm strategy.

Are patients with preoperative synovitis suitable for unicompartmental knee arthroplasty? Magnetic resonance imaging evidence from a retrospective cohort study.

BACKGROUND: The use of unicompartmental knee arthroplasty (UKA) in patients with preoperative synovitis is controversial. This study aimed to investigate the association between synovitis detected by magnetic resonance imaging (MRI) and prognosis after UKA. METHODS: Synovitis was graded using the MRI Osteoarthritis Knee Score criteria based on preoperative MRI findings of 132 UKAs performed between June 2020 and August 2021. The Knee Society Knee Score (KS-KS) and the Knee Society Function Score were collected preoperatively and 1 year postoperatively. The relationship between synovitis and the changes in the Knee Society score was analyzed using logistic regression. RESULTS: Univariate logistic regression showed that patients with higher preoperative synovitis scores (odds ratio (OR) = 1.925, 95% confidence interval (CI): 1.482-2.500, P < 0.001) had higher KS-KS changes. After adjusting for confounding variables, synovitis was proven to be an independent factor for KS-KS improvement after UKA in multivariate logistic regression (OR = 1.814, 95% CI: 1.354-2.430, P < 0.001). Before UKA, patients with synovitis had lower pain scores (PS) than patients without synovitis (95% CI: -17.159 - -11.160, t = -9.347, P < 0.001). There was no difference in PS between the two groups after UKA (95% CI: -6.559 - 0.345, t = -1.782, P = 0.077). CONCLUSIONS: Patients with synovitis can achieve good improvement of pain symptoms, and the efficacy is not inferior to that of non-synovitis patients after UKA.

Hypoxia-induced physiological responses in fish: From organism to tissue to molecular levels.

Dissolved oxygen (DO) in water bodies is a prerequisite for fish survival and plays a crucial role in fish growth, development, and physiological processes. However, with increasing eutrophication, greenhouse effects, and extreme weather conditions, DO levels in aquatic environments often become lower than normal. This leads to stress in fish, causing them to exhibit escape behavior, inhibits their growth and development, and causes tissue damage. Moreover, oxidative stress, decreased immune function, and altered metabolism have been observed. Severe hypoxia can cause massive fish mortality, resulting in significant economic losses to the aquaculture industry. In response to hypoxia, fish exhibit a series of behavioral and physiological changes that are self-protective mechanisms formed through long-term evolution. This review summarizes the effects of hypoxic stress on fish, including the asphyxiation point, behavior, growth and reproduction, tissue structure, physiological and biochemical processes, and regulation of gene expression. Furthermore, future research directions are discussed to provide new insights and references.

Chaotropic Effect Stabilized Radical-Containing Supramolecular Organic Frameworks for Photothermal Therapy.

Radical-containing frameworks (RCFs) have emerged as promising functional materials in various fields due to the combination of the highly ordered frame structure and the fascinating property of organic radicals. Here, the first example of radical-containing supramolecular organic frameworks (SOFs) fabricated by the chaotropic effect between closo-dodecaborate cluster (B12 H122- ) and 2,4,6-tri(4-pyridyl)-1,3,5-triazine (TPT3+ ) is presented. The SOFs can be easily synthesized by stirring the B12 H122- and the TPT3+ in aqueous solution through self-assembly. Upon 435 nm light irradiation, the SOFs exhibits photochromic behavior from slight yellow (SOF-1) to dark purple (SOF-2). Electron paramagnetic resonance spectroscopy also reveals that stable radicals are generated in situ after light irradiation. Powder X-ray diffraction demonstrates the SOFs maintain their structural stabilities upon light irradiation. More interestingly, the radical-containing SOFs exhibit efficient photothermal effect under 660 nm light irradiation, which can be applied as photothermal agent for antibacterial application both in vitro and in vivo. This work highlights the construction of RCFs through supramolecular self-assembly, which may arouse applications in energy, catalysis, photoluminescence, and biomedical fields.

Effects of Benzoapyrene on migration and invasion of lung cancer cells functioning by TNF-α.

In this study, we attempted to find out the underlying mechanism of Benzoapyrene and metastasis of lung cancer cells. We also did experiments to testify the connection between BaP and its potential target, TNF-α. Cell median lethal dose (IC50 ) of both cells was measured by crystal violet method. Quantitative real-time reverse transcription PCR (qRT-PCR) and Western blot were employed to detect the expression of TNF-α. Wound healing assay and transwell assay were utilized to testify the impacts of BaP and TNF-α on the metastasis of lung cancer cells. Cell death rate was elevated with the increase of BaP concentration. BaP increased the number of metastatic cells of lung cancer. The expressions of TNF-α pathway-associated protein (TNF-α, NF-kB [P65], Caspase3, and Caspase8) were enhanced by overexpressed BaP. TNF-α shRNA suppressed the positive effects of BaP on migration and invasion of lung cancer cells. Our study validated the positive effects of BaP on the metastasis of lung cancer cells. We also revealed the instrumental role of TNF-α in helping the development of lung cancer cells induced by BaP.

[Nonparametric method of estimating survival functions containing right-censored and interval-censored data].

Missing data represent a general problem in many scientific fields, especially in medical survival analysis. Dealing with censored data, interpolation method is one of important methods. However, most of the interpolation methods replace the censored data with the exact data, which will distort the real distribution of the censored data and reduce the probability of the real data falling into the interpolation data. In order to solve this problem, we in this paper propose a nonparametric method of estimating the survival function of right-censored and interval-censored data and compare its performance to SC (self-consistent) algorithm. Comparing to the average interpolation and the nearest neighbor interpolation method, the proposed method in this paper replaces the right-censored data with the interval-censored data, and greatly improves the probability of the real data falling into imputation interval. Then it bases on the empirical distribution theory to estimate the survival function of right-censored and interval-censored data. The results of numerical examples and a real breast cancer data set demonstrated that the proposed method had higher accuracy and better robustness for the different proportion of the censored data. This paper provides a good method to compare the clinical treatments performance with estimation of the survival data of the patients. This pro vides some help to the medical survival data analysis.

Platinum group nanoparticles doped BCN matrix: Efficient catalysts for the electrocatalytic reduction of nitrate to ammonia.

The effective treatment of nitrate (NO3-) in water as a nitrogen source and electrocatalytic NO3- reduction to ammonia (NH3) (NRA) have become preferred methods for NO3--to-NH3 conversion. Achieving efficient NO3--to-NH3 conversion requires the design and development of electrode materials with high activity and efficiency for the electrocatalytic NRA reaction. Herein, based on the special properties of dodecahydro-closo-dodecaborate anions, a BCN matrix, loaded with platinum-group nanoparticles (namely, Pd/BCN, Pt/BCN, and Ru/BCN), was prepared using a simple method for the electrocatalytic NRA reaction. Results showed that Pd/BCN exerts the best catalytic effect on the NRA reaction. The NH3 production rate reached 12.71 mg h-1 mgcat.-1 at -1.0 V vs. RHE. Faraday efficiency reached 91.79 %, which can be attributed to the more uniform distribution of the nanoparticles. Furthermore, Pd/BCN exhibited high cycling stability and resistance to ionic interference. Moreover, the density functional theory calculations indicated that small and well-distributed Pd nanoclusters in the BCN matrix have a large active surface area and promote the catalytic process. This study provides a new strategy to design catalysts for green ammonia synthesis.

Anti-tumor therapy through high ROS performance induced by Ag nanoenzyme from boron cluster with halloysite clay nanotubes.

The conventional silver nanoparticles (Ag NPs) are characterized with high loading rate and stacking phenomenon, leading to shedding caused biotoxicity and low catalytic efficiency. This seriously hinders their application in biomedicine. Here, we modified the highly dispersible Ag NPs and Ag single-atoms (SAs) synthesis by combining the halloysite clay nanotubes (HNTs) and dodecahydro-dodecaborate (closo-[B12H12]2-) to increase the biocompatible properties and decrease the loading rate. This novel Ag single-atom nanoenzyme alongside Ag NPs nanoenzyme avoid the elevated-temperature calcination while maintaining the exceptionally high-level efficiency of Ag utilization via the reducibility and coordination stabilization of closo-[B12H12]2- and HNTs. With theoretical calculation and electron paramagnetic resonance, we confirmed that both Ag SAzymes and Ag NPs in HNT@B12H12@Ag nanoenzyme are capable decompose the H2O2 into hydroxyl radical (·OH). For the application, we investigated the catalytic activity in the tumor cells and antitumor effects of HNT@B12H12@Ag nanoenzyme both in vitro and in vivo, and confirmed that it effectively suppressed melanoma growth through ·OH generation, with limited biotoxicity. This study provides a novel Ag nanoenzyme synthesis approach to increase the possibility of its clinical application.

Balancing Bioresponsive Biofilm Eradication and Guided Tissue Repair via Pro-Efferocytosis and Bidirectional Pyroptosis Regulation during Implant Surgery.

There is an increasingly growing demand to balance tissue repair guidance and opportunistic infection (OI) inhibition in clinical implant surgery. Herein, we developed a nanoadjuvant for all-stage tissue repair guidance and biofilm-responsive OI eradication via in situ incorporating Cobaltiprotoporphyrin (CoPP) into Prussian blue (PB) to prepare PB-CoPP nanozymes (PCZs). Released CoPP possesses a pro-efferocytosis effect for eliminating apoptotic and progressing necrotic cells in tissue trauma, thus preventing secondary inflammation. Once OIs occur, PCZs with switchable nanocatalytic capacity can achieve bidirectional pyroptosis regulation. Once reaching the acidic biofilm microenvironment, PCZs possess peroxidase (POD)-like activity that can generate reactive oxygen species (ROS) to eradicate bacterial biofilms, especially when synergized with the photothermal effect. Furthermore, generated ROS can promote macrophage pyroptosis to secrete inflammatory cytokines and antimicrobial proteins for biofilm eradication in vivo. After eradicating the biofilm, PCZs possess catalase (CAT)-like activity in a neutral environment, which can scavenge ROS and inhibit macrophage pyroptosis, thereby improving the inflammatory microenvironment. Briefly, PCZs as nanoadjuvants feature the capability of all-stage tissue repair guidance and biofilm-responsive OI inhibition that can be routinely performed in all implant surgeries, providing a wide range of application prospects and commercial translational value.

Comparative evaluation of nutritional quality and flavor characteristics for Micropterus salmoides muscle in different aquaculture systems.

To investigate the nutritional quality and flavor characteristics of Micropterus salmoides muscle cultivated in the pond (P), in-pond raceway (IPRS), and industrial aquaponics (ARAS) systems, we comprehensively analyzed texture properties, nutrient compositions, and volatile compounds. Our results revealed firmer flesh in P-cultured fish due to greater hardness and mastication. ARAS fish exhibited lower crude fat but higher crude protein and muscle glycogen. Notably, recirculating aquaculture significantly elevated total amino acids, minerals, and ΣPUFA/ΣSFA ratio, enhancing nutritional value. Pyrazine,2-methoxy-3-(2-methylpropyl)-, and ß-Ionone were identified as key flavor compounds. Volatile metabolites in all systems were dominated by woody, herbal, and sweet aroma profiles, with ARAS achieving the highest odor activity value, suggesting improved overall flavor. This study underscores the pivotal role of recirculating aquaculture in enhancing Micropterus salmoides quality, positioning it as a new quality productive force.

Nanoadjuvant-triggered STING activation evokes systemic immunotherapy for repetitive implant-related infections.

Repetitive implant-related infections (IRIs) are devastating complications in orthopedic surgery, threatening implant survival and even the life of the host. Biofilms conceal bacterial-associated antigens (BAAs) and result in a "cold tumor"-like immune silent microenvironment, allowing the persistence of IRIs. To address this challenge, an iron-based covalent organic framed nanoadjuvant doped with curcumin and platinum (CFCP) was designed in the present study to achieve efficient treatment of IRIs by inducing a systemic immune response. Specifically, enhanced sonodynamic therapy (SDT) from CFCP combined with iron ion metabolic interference increased the release of bacterial-associated double-stranded DNA (dsDNA). Immunogenic dsDNA promoted dendritic cell (DC) maturation through activation of the stimulator of interferon gene (STING) and amplified the immune stimulation of neutrophils via interferon-ß (IFN-ß). At the same time, enhanced BAA presentation aroused humoral immunity in B and T cells, creating long-term resistance to repetitive infections. Encouragingly, CFCP served as neoadjuvant immunotherapy for sustained antibacterial protection on implants and was expected to guide clinical IRI treatment and relapse prevention.

Boron-induced activation of Ru nanoparticles anchored on carbon nanotubes for the enhanced pH-independent hydrogen evolution reaction.

As a promising dopant, electron deficient B atom not only tunes the electronic structure of electrocatalysts for improving their intrinsic catalytic activities, but also combines with hydroxy radical as strong adsorption sites for accelerating the water dissociation during the hydrogen evolution reaction (HER). In this paper, we report an electrocatalyst based on boron-modified Ru anchored on carbon nanotubes (B-Ru@CNT) that shows impressive HER activity in acidic and alkaline media. The boron-rich closo-[B12H12]2- borane was selected as a moderately strong reductant for the in situ reduction of a Ru salt, which yielded B-doped Ru nanoparticles. The experimental and theoretical results indicate that the incorporation of B not only weakens the Ru-H bond and downshifts the d-bond centre of Ru from the Fermi level by reducing the electron density at Ru but also accelerates the water dissociation reaction by providing B sites, which strongly adsorb OH* intermediates, and nearby Ru sites, which act as sites for the adsorption of the H* intermediate, thus boosting the HER performance and enhancing the HER kinetics. As a result of the tuning of the electronic structure via B doping, B-Ru@CNT showed excellent HER performance, yielding overpotentials of 17 and 62 mV at a current density of 10 mA cm-2 in alkaline and acidic solutions, respectively. These results indicate that our synthetic method is a promising route to B-doped metallic Ru with enhanced pH-independent HER performance.

Increased resting-state alpha coherence and impaired inhibition control in young smokers.

Exposure to nicotine is the first cause of entirely preventable death killing, which is commonly initiated in adolescence. Previous studies revealed the changes of electroencephalography (EEG) and inhibition control in smokers. However, little is known about the specific link between alpha coherence during the resting state and inhibition control ability in young smokers. The present study aimed to investigate inter-hemispherical and frontal-parietal alpha coherence changes and assessed the relationships between alpha coherence and inhibition control in young smokers. We collected resting-state EEG data from 23 young smokers and 24 healthy controls. Inhibition control ability was assessed by a Go/NoGo task. Compared to healthy controls, young smokers exhibited increased inter-hemispherical and frontal-parietal alpha coherence. Furthermore, young smokers committed more NoGo errors in the Go/NogGo task. It is noteworthy that alpha coherence at the frontal electrode sites was positively correlated with NoGo errors in healthy controls, whereas inverse correlations were observed in young smokers. Our findings suggested that alterations of alpha coherence may provide support to the earlier nicotine-dependence-related research findings, which may help us to understand the neuropathology of inhibitory control in young smokers.

Bone regeneration materials and their application over 20 years: A bibliometric study and systematic review.

Bone regeneration materials (BRMs) bring us new sights into the clinical management bone defects. With advances in BRMs technologies, new strategies are emerging to promote bone regeneration. The aim of this study was to comprehensively assess the existing research and recent progress on BRMs, thus providing useful insights into contemporary research, as well as to explore potential future directions within the scope of bone regeneration therapy. A comprehensive literature review using formal data mining procedures was performed to explore the global trends of selected areas of research for the past 20 years. The study applied bibliometric methods and knowledge visualization techniques to identify and investigate publications based on the publication year (between 2002 and 2021), document type, language, country, institution, author, journal, keywords, and citation number. The most productive countries were China, United States, and Italy. The most prolific journal in the BRM field was Acta Biomaterialia, closely followed by Biomaterials. Moreover, recent investigations have been focused on extracellular matrices (ECMs) (370 publications), hydrogel materials (286 publications), and drug delivery systems (220 publications). Research hotspots related to BRMs and extracellular matrices from 2002 to 2011 were growth factor, bone morphogenetic protein (BMP)-2, and mesenchymal stem cell (MSC), whereas after 2012 were composite scaffolds. Between 2002 and 2011, studies related to BRMs and hydrogels were focused on BMP-2, in vivo, and in vitro investigations, whereas it turned to the exploration of MSCs, mechanical properties, and osteogenic differentiation after 2012. Research hotspots related to BRM and drug delivery were fibroblast growth factor, mesoporous materials, and controlled release during 2002-2011, and electrospinning, antibacterial activity, and in vitro bioactivity after 2012. Overall, composite scaffolds, 3D printing technology, and antibacterial activity were found to have an important intersection within BRM investigations, representing relevant research fields for the future. Taken together, this extensive analysis highlights the existing literature and findings that advance scientific insights into bone tissue engineering and its subsequent applications.

Altered resting-state electroencephalography microstate characteristics in young male smokers.

The development of nicotine addiction was associated with the abnormalities of intrinsic functional networks during the resting state in young adult smokers. As a whole-brain imaging approach, EEG microstate analysis treated multichannel EEG recordings as a series of quasi-steady microscopic states which were related to the resting-state networks (RSNs) found by fMRI. The aim of this study was to examine whether the resting-state EEG microstate analysis may provide novel insights into the abnormal temporal properties of intrinsic brain activities in young smokers. We used 64-channel resting-state EEG datasets to investigate alterations in microstate characteristics between twenty-five young smokers and 25 age- and gender-matched non-smoking controls. Four classic EEG microstates (microstate A, B, C, and D) were obtained, and the four temporal parameters of each microstate were extracted, i.e., duration, occurrence, coverage, and transition probabilities. Compared with non-smoking controls, young smokers showed decreased occurrence of microstate C and increased duration of microstate D. Furthermore, both the duration and coverage of microstate D were significantly negatively correlated with Fagerstrom Test of Nicotine Dependence (FTND) in young smoker group. The complex changes in the microstate time-domain parameters might correspond to the abnormalities of RSNs in analyses of FC measured with fMRI in the previous studies and indicate the altered specific brain functions in young smokers. Microstate D could be potentially represented as a selective biomarker for predicting the dependence degree of adolescent smokers on cigarettes. These results suggested that EEG microstate analysis might detect the deviant functions of large-scale cortical activities in young smokers and provide a new perspective for the study of brain networks of adolescent smokers.

A Review: Microbial Diversity and Function of Fermented Meat Products in China.

Fermented meat products have a long history in China. These products exhibit a characteristic unique flavor, compact meat quality, clear color, long shelf life and wide variety and are easy to transport. During the processing and storage of fermented meat products, microorganisms are present and exhibit diverse characteristics. Microorganisms can accelerate the degradation of proteins and fats to produce flavor compounds, inhibit the growth and reproduction of heterozygous bacteria, and reduce the content of chemical pollutants. This paper reviews the microbial diversity of Chinese ham, sausage, preserved meat, pressed salted duck, preserved fish and air-dried meat and provides analyses of the microbial compositions of various products. Due to the differences in raw materials, technology, auxiliary materials, and fermentation technology, the microbial species found in various fermented meat products in China are different. However, most fermented meat products in China are subjected to pickling and fermentation, so their microbial compositions also have similarities. Microorganisms in fermented meat products mainly include staphylococci, lactobacilli, micrococci, yeasts, and molds. The study of microbial diversity is of great significance for the formation of quality flavor and the safety control of fermented meat products, and it provides some theoretical reference for the study of fermented meat products in China.

Controlled preparation of a MCC-g-AM/EDA/PA loaded Fe(iii) adsorbent by the pre-radiation grafting method and its application for the adsorption removal of phosphate.

A new spherical cellulose-based adsorbent and high phosphate removal rate microcrystalline cellulose-g-acrylamide/ethylenediamine/phthalic anhydride (MCC-g-AM/EDA/PA) loaded Fe(iii) adsorbent was prepared by a pre-radiation grafting and chemical modification method. Fe(iii) was successfully introduced into the modified grafted chains of the MCC-g-AM/EDA/PA resin, and characterized by FTIR, TG, XRD, SEM and XPS. The optimized conditions for the grafting reaction of acrylamide (AM) onto MCC were 20% AM emulsion at an absorbed dose of 30 kGy, and a grafting rate as high as 247%. In addition, the adsorption performance of the adsorbent was tested by static adsorption experiments with phosphate. The adsorbent resin showed excellent adsorption performance under alkaline conditions, contributions to the synergetic effect of precipitation, and inner-sphere surface complex reactions. The adsorption efficiency can reach 89.7% at low concentration. In summary, the neotype spherical cellulose-based adsorbent has the advantages of being separation-free in bulk materials, avoiding secondary pollution, and being easy to recycle, and it could be employed as an environmentally friendly adsorbent for phosphate removal in eutrophic water.

Cubic platinum nanoparticles capped with Cs2[closo-B12H12] as an effective oxidation catalyst for converting methane to ethanol.

Direct conversion of methane to alcohol remains a key challenge. Here, we report a novel aqueous catalyst, cubic platinum (Pt) nanoparticles capped with Cs2[closo-B12H12], capable of direct oxidation of methane to ethanol and methanol with H2O2 and O2 under facile conditions. The selective conversion to ethanol exceeded 97% with a yield reaching 148.41 mol·kgcat-1·h-1 at 50 °C. Experiments with 5,5'-dimethy1-1-pyrroline-N-oxide (DMPO) and electron paramagnetic resonance (EPR) tests revealed that methane oxidation occurred via free-radical chain reactions involving CH3, CH3CH2, and HO radicals. Theoretical analysis suggested that the {1 0 0} surface of the Pt nanoparticles was capped with Cs2[closo-B12H12] mediated by Pt-B bonds with a binding energy of -278.6 kcal/mol. This promoted the growth of particles along the direction of the (1 0 0) facets and finally formed a cubic structure. The EPR tests combined with theoretical calculations confirmed the hypothesis that methane-ethane-ethanol conversion was mediated by the catalyst by employing the features of nano-platinum and Cs2[closo-B12H12], on which only C1 and C2 products were generated, while no products with three or more carbon atoms were detected in the reaction systems described above.

[Effect of estradiol on biofilm formation of staphylococcus epidermidis after breast implant surgery].

OBJECTIVE: ?To investigate the effect of the estradiol hormones on biofilm formati on and structure of Staphylococcus epidermidis after breast implant surgery. METHODS: ?The concentration of Staphylococcus epidermidis strains ATCC35984 was adjusted to 1×107 CFU/mL or 1×108 CFU/mL, and the type strains were incubated on the surface of silica gel in 125 pmol/L estradiol suspensions to prepare bacterial biofilms model in vitro. After cultured in vitro for 4, 6, 12, 24, 48, and 72 hours, bacteria growth and biofilm formation ability were assessed by means of the XTT and crystal violet staining respectively. According to the above results, the bacterial suspension concentration was selected for experiments. The experimental concentration of Staphylococcus epidermidis ATCC35984 suspension and the concentrations of 50, 125, 250, 500 pmol/L estradiol suspensions were mixed with silica gel respectively to prepare biofilm model in vitro, no estradiol suspension served as control group. The experimental concentration of Staphylococcus epidermidis ATCC12228 suspension was used to prepare the same model in the negative control. After cultured in vitro for 4, 6, 12, 24, 48, and 72 hours, the same methods were used to assess the bacteria growth dynamics and biofilm forming ability, and the scanning electron microscope (SEM) was used to observe bacterial biofilm structure cultured on the surface of silica gel; the laser scanning confocal microscope (CLSM) was used to measure bacterial biofilm thickness on the surface of silica gel after 6, 12, and 24 hours. RESULTS: ?According to the results of semi quantitative detection of crystal violet stain and XTT methods, the bacterial suspension of 1×107 CFU/mL was selected for the experiment. XTT results indicated that the growth rates of ATCC12228 strain (at 4, 6, 12, 24, and 72 hours ) and ATCC35984 strain (at 4, 6, 24, and 72 hours) in 125, 250, and 500 pmol/L estradiol were significantly faster than those in 0 and 50 pmol/L (P<0.05). The growth rate of 500 pmol/L group was significantly faster than 125 and 250 pmol/L groups at 4, 6, and 72 hours (P<0.05), and the growth rate of 250 pmol/L group was significantly faster than that of 125 pmol/L group at 72 hours (P<0.05), but there was no significant difference between 0 and 50 pmol/L groups (P>0.05). At the same time point and same estradiol concentration, the growth rates showed no significant difference between 2 strains (P>0.05). Semi quantitative detection of crystal violet staining showed no biofilm formed in ATCC12228 strain in all estradiol concentration groups at different time points. In ATCC35984 strain, the biofilm was found at 4 hours and gradually thickened with time, reached the peak at 24 hours. After cultured for 4 and 6 hours, the biofilm of 0 pmol/L groups were significantly thicker than that of 125, 250, and 500 pmol/L groups (P<0.05). At 12 hours, the 125 pmol/L group had the thickest biofilm, showing significant difference when compared with other groups (P<0.05). The CLSM showed ATCC35984 biofilm thickness of 125, 250, and 500 pmol/L was significantly less than that of 0 and 50 pmol/L groups at 6 hours (P<0.05), but difference was not significant between other groups (P>0.05). Then the thickness of the biofilm increased gradually, and the thickness of 125 pmol/L group was significantly larger than that of other concentration groups at 12 and 24 hours (P<0.05). The SEM observation showed that the biofilm of 125 pmol/L group was denser and thicker than that of the other concentration groups at each time point. CONCLUSIONS: ?High level estradiol can promote bacteria growth, biofilm formation, and biofilm maturity of Staphylococcus epidermidis.