Controllable AgNPs encapsulation to construct biocompatible and antibacterial titanium implant.

Silver nanoparticles (AgNPs) are progressively becoming an in-demand material for both medical and life use due to their effective antimicrobial properties. The high surface area-to-volume ratio endows AgNPs with enhanced antibacterial capacity accompanied by inevitable cytotoxicity. Surface coating technique could precisely regulate the particle shape, aggregation, and Ag+ release pattern of AgNPs, by which the cytotoxicity could be significantly reduced. Various coating methods have been explored to shell AgNPs, but it remains a great challenge to precisely control the aggregation state of AgNPs and their shell thickness. Herein, we proposed a simple method to prepare a tunable polydopamine (pDA) coating shell on AgNPs just by tuning the reaction pH and temperature, yet we obtained high antibacterial property and excellent biocompatibility. SEM and TEM revealed that pDA coated AgNPs can form core-shell structures with different aggregation states and shell thickness. Both in vitro and in vivo antibacterial tests show that acid condition and heat-treatment lead to appropriate AgNPs cores and pDA shell structures, which endow Ti with sustained antibacterial properties and preferable cell compatibility. One month of implantation in an infected animal model demonstrated that the obtained surface could promote osteogenesis and inhibit inflammation due to its strong antibacterial properties. Therefore, this study provides a promising approach to fabricate biocompatible antibacterial surface.

Performance of a Three-Dimensional Electrochemical Reactor (3DER) on Bisphenol A Degradation.

This study constructed a three-dimensional electrochemical reactor (3DER) using meshed stainless steel sheets and titanic magnetite particles (TMP) to investigate bisphenol A (BPA) degradation through the synergistic action of electrical current and TMP. We examined some TMP characteristics, such as particle size, specific surface areas, X-ray diffraction, surface imaging, elemental constituents, and electrical resistivity. It was found that TMP was a micron-level material with excellent electrical conductivity, and it could be regarded as a magnetite-based material comprising Fe(II) and Fe(III). The single-factor experiment determined the optimal conditions for BPA removal in 3DER, specifically by introducing 200 ml of BPA-simulated wastewater (10 mg L-1) into 3DER. At the initial pH of 9.00, current and electrodes gap of 300 mA and 15 mm, respectively, and adding 1 ml of 0.5 M potassium peroxymonosulfate and 1 g TMP, > 98% of BPA was removed after 55 min of electrochemical reaction. In addition, liquid chromatography-mass spectrometry identified the intermediates formed during the BPA treatment, showing two possible pathways for BPA degradation. The final degradation intermediates were chain organics with simple molecular structures. This research provided an understanding of the potential application of 3DER for BPA removal in water.

Electrochemical treatment for leachate membrane retentate: Performance comparison of electrochemical oxidation and electro-coagulation technology.

With the widespread use of membrane in advanced treatment of leachate, China produces a large amount of leachate membrane retentate (LMR) (≈23.4 million tons) annually, which is usually treated by incineration or recirculation in engineering, but these technologies have many drawbacks. LMR is suitable for electrochemical treatment due to its high electrical conductivity. This study compared the performances of electrochemical oxidation (EO) and electro-coagulation (EC) technology on LMR treatment under different experimental conditions, including anode material, current density, initial pH and reaction time. We found that EO optimal conditions achieved 70.1%, 83.1%, 78.7%, 98.7%, and 69.7% removal of total organic carbon (TOC), UV absorption (at 254 nm), chromaticity, ammonia nitrogen (NH3-N), and total nitrogen (TN), respectively. Compared with EO, EC exhibited a similar removal ability for orgainics and better removals of chroma, but much less performance for removing nitrogen pollutants in the same reaction time, that is, removals of NH3-N and TN were only 31.5% and 36.2%, respectively. Meanwhile, EC showed much higher instantaneous current efficiency of COD than EO under its optimal reaction time (120 min). In addition, the UV-Vis spectra and 3D fluorescence spectra indicated that EO exhibited relatively outstanding performance in decomposing dissolved organic matter (DOM) with rather complicated structures than EC. Also, the flow field-flow fractionation technique demonstrated that EO preferentially destroy humic-like, large molecular weight DOM, and converting them to smaller molecules, which resulted in more volatile organic compounds in EO samples than EC samples. While EC had little selectivity in the removal of organics, except humic-like DOM with relative small molecular. These findings can provide a theoretical basis for the electrochemical treatment of LMR.

[Chlorhexidine-grafted phenolamine coating to improve antibacterial property of the titanium surface].

Objective: To investigate the physicochemical properties of pure titanium surface grafted with chlorhexidine (CHX) by phenolamine coating, and to evaluate its antibacterial activity and osteoblast-compatibility in vitro. Methods: Control group was obtained by alkali and thermal treatment, and then immersed in the mixture of epigallocatechin-3-gallate/hexamethylene diamine (coating group). Phenolamine coating was deposited on the surface, and then it was immersed in CHX solution to obtain the grafted surface of CHX (grafting group). The surface morphology was observed by scanning electron microscope, the surface element composition was analyzed by X-ray photoelectron spectroscopy, and the surface hydrophilicity was measured by water contact angle test. Live/dead bacterial staining, nephelometery, and inhibition zone method were executed to evaluate the antibacterial property. Cytotoxicity was evaluated by MTT assay and cell fluorescence staining. Bacteria-MC3T3-E1 cells co-culture was conducted to evaluate the cell viability on the samples under the circumstance with bacteria. Results: Scanning electron microscope observation results showed that deposits of coating group and grafting group increased successively and gradually covered the porous structure. X-ray photoelectron spectroscopy results showed the peak of N1s enhanced and the peak of Cl2p appeared in grafting group. Water contact angle test results showed that the hydrophilic angle of three groups increased in turn, and there was significant difference between groups ( P<0.05). Live/dead bacteria staining results showed that the grafting group had the least amount of bacteria adhered to the surface and the proportion of dead bacteria was high. The grafting group had a transparent inhibition zone around it and the absorbance ( A) value did not increase, showing significant difference when compared with control group and coating group ( P<0.05). MTT assay and cell fluorescence staining results showed that the number of adherent cells on the surface of the grafting group was the least, but the adherent cells had good proliferation activity. Bacteria-cell co-culture results showed that there was no bacteria on the surface of grafting group but live cells adhered well. Conclusion: CHX-grafted phenolamine coating has the ability to inhibit bacterial adhesion and proliferation, and effectively protect cell adhesion and proliferation in a bacterial environment.

Serum Triglycerides Are Related to Chronic Kidney Disease (CKD) Stage 2 in Young and Middle-Aged Chinese Individuals During Routine Health Examination.

BACKGROUND The aim of this study was to determine the risk factors for early chronic kidney disease (CKD) (GFR 60-89 ml/min/1.73 m²; CKD stage 2) in asymptomatic Chinese individuals undergoing routine health examination. MATERIAL AND METHODS This cross-sectional study enrolled 9100 individuals who received voluntary medical examinations between 10/01/2011 and 09/30/2017. Demographic data, clinical history, clinical examination, medication, smoking, alcohol, blood biochemistry, urinalysis, and carotid ultrasound were extracted from the medical records. All laboratory analyses were performed routinely. Multivariable logistic regression for factors predicting CKD stage 2 was performed. RESULTS A total of 9100 individuals were enrolled (age of 18-65 and 65.4% male). CKD stage 2 was found in 1989/9100 individuals (21.9%). Male gender (OR=6.711, 95%CI: 5.376-8.403, P<0.001), older age (OR=1.077, 95%CI: 1.068-1.086, P<0.001), hemoglobin levels (OR=1.051, 95%CI: 1.046-1.057, P<0.001), triglycerides levels (OR=1.174, 95%CI: 1.067-1.292, P=0.001), HDL-C (OR=0.539, 95%CI: 0.380-0.763, P<0.001), Lp(a) levels (OR=1.000, 95%CI: 1.000-1.001, P=0.03), and carotid atherosclerosis (OR=1.248, 95%CI: 1.005-1.550, P=0.045) were associated with CKD stage 2 among all subjects. Serum triglycerides levels were associated with CKD stage 2 in the 18-45 and 45-65 years of age subgroups. CONCLUSIONS Factors that are routinely assessed during routine health examinations (male gender, age, hemoglobin levels, triglycerides levels, HDL-C, Lp(a) levels, and carotid atherosclerosis) can help identify individuals at higher risk of having CKD stage 2. The Chinese dyslipidemia is characterized by high triglycerides and low HDL-C and occurs in young and middle-aged individuals. Those factors could help identify individuals at higher risk for CKD stage 2 and who could benefit from preventive treatments.

Indoxyl sulfate accelerates vascular smooth muscle cell calcification via microRNA-29b dependent regulation of Wnt/ß-catenin signaling.

Vascular calcification (VC) is a very common phenomenon in patients with chronic kidney disease(CKD) and it increases the incidence of cardiovascular disease and leads to high mortality in CKD patients. It has been reported that some microRNAs (miRs) play roles in vascular calcification as an epigenetic regulator. Indoxyl sulfate (IS) is a protein-bound uremic toxin which has been proven as one of the major risk factors of cardiovascular disease in CKD. Here we investigated whether microRNA-29b (miR-29b) is involved in IS-induced vascular calcification. We found that vascular miR-29b was down-regulated in radial arteries of patients with end-stage renal disease. Consistently, IS also decreased miR-29b expression in human aortic smooth muscle cells (HASMCs) and potentiated their calcification. MiR-29b mimics significantly suppressed, while miR-29b anti-miR markedly enhanced, IS-induced runt-related transcription factor 2 and osteopontin expression. The expression of Wnt7b/ß-catenin in radial arteries was higher in end stage renal disease than in control group, and IS increased Wnt7b/ß-catenin expression in HASMCs as early as 3days after stimulation. Furthermore, miR-29b mimics potently repressed Wnt7b/ß-catenin protein expression in HASMCs, whereas miR-29b anti-miR increased their expression, indicating miR-29b indeed negatively regulates Wnt7b/ß-catenin signaling. Dickkopf-1 protein, the Wnt/ß-catenin signaling inhibitor, suppressed anti-miR-29b-enhanced HASMCs calcification. Our data thus indicate that miR-29b downregulation and Wnt/ß-catenin signaling activation may be the key mechanism of IS induced vascular calcification in chronic kidney disease.

Hydrogen-Rich Saline Alleviates Kidney Fibrosis Following AKI and Retains Klotho Expression.

Purpose: Acute kidney injury (AKI) is a prominent risk factor for the development of chronic kidney disease (CKD). To date, the related mechanism and effective therapy have not been rigorously explored. The present study aims to investigate the reno-protection of hydrogen-rich saline (HRS) against ischemia/reperfusion (IR)-induced AKI. Methods: Adult male C57 mice were randomly allocated into three groups: Sham, IR, IR+HRS. Renal IR injury model was generated via 35 min occlusion of bilateral kidney pedicles, and then, mice were administered with different treatments intraperitoneally in various groups. After 14- or 28-day treatment, mice were perfused and the kidneys were collected following reperfusion. Many proteins were detected by western blots, including renal fibrotic proteins [a-smooth muscle actin (a-SMA), collagen I (Col I)], Klotho, the methylation of Klotho, damage-regulated autophagy modulator (Beclin-1), and microtubule-associated protein light 3-II (LC3-II). Finally, the levels of serum blood urea nitrogen (BUN) and creatinine (Cr) were measured to investigate the renal function. Results: Histological data showed that the HRS treatment significantly decreased the fibrosis in renal tissues when compared with the IR group, and both of BUN and Cr were lower in the HRS group than IR group (8.9 ± 0.6 vs. 9.9 ± 0.1 mmol/l, 51 ± 6.5 vs. 60 ± 5.8 µmol/l) (P < 0.05). The expression of fibrotic markers, a-SMA and Col I, showed a robust increase in IR injury models than the Sham group, which was consistent with the result of Trichrome staining. However, the levels of a-SMA and Col I expression were sharply decreased in the IR+HRS group (P < 0.05). IR injury also enhanced LC3-II and Beclin-1 expression, but decreased Klotho level. The Klotho level was alleviated by HRS, but LC3-II and Beclin-1 were starkly enhanced in HRS group (P < 0.05). Conclusion: HRS showed a protective effect in the prevention of renal injury and could inhibit renal fibrosis after IR injury in mice. This role of HRS might be exerted via retaining Klotho expression and activating autophagy in the kidney.