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1.
J Nanosci Nanotechnol ; 20(3): 1878-1883, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31492356

RESUMO

It is demonstrated that Mg, Cr, Mn and B can be doped close to GaAs surface by plasma doping without external bias at room temperature (RT). The process only takes a few minutes, and impurity densities in the range of 1018-1021/cm3 can be achieved with doping depths about twenty nanometers. The experiment results are analyzed and the physical mechanism is tentatively explained as follows: during the doping process, impurity ion implantation under plasma sheath voltage takes place, simultaneously, plasma stimulates RT diffusion of impurity atom, which plays the main role in the doping process. The enhanced RT diffusion coefficients of Mg, Cr, Mn and B in GaAs are all in the order of magnitude of 10-15 cm2sec-1. This is reported for the first time among all kinds of plasma assisted doping methods.

2.
Aesthetic Plast Surg ; 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31485763

RESUMO

BACKGROUND: To assess preliminarily the effect of concentrated growth factor (CGF) for repair of nasal septal mucosal defect after rhinoplasty. METHODS: Ten women with mucosal defects of the nasal septum were enrolled from May 2017 to May 2018. Liquid and gel CGF was prepared from each patient's blood sample using a Medifuge system, including benchtop centrifuge. After debridement of the defect, the prepared liquid CGF was injected around the wound, and a membranous CGF film was applied to the surface. Vaseline gauze was used to pack the nostrils. All patients were treated with CGF at intervals from 3 to 5 days. RESULTS: After 3 to 12 treatments, all the patients achieved successful repair of the nasal septal mucosal defect, with good appearance and function. During a follow-up of 3 to 6 months, no recurrence was observed. CONCLUSION: CGF appeared to have great curative effect for patients with nasal septal mucosal defects after rhinoplasty. The procedure was easy to perform and should be considered worthwhile in clinical practice. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

3.
Health Aff (Millwood) ; 38(9): 1468-1474, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31479374

RESUMO

Enabling services address a combination of social determinants of health and barriers to access to primary care and are intended to reduce health disparities. They include care coordination; health education; transportation; and assistance with obtaining food, shelter, and benefits. Empirical evidence of enabling services' potential contribution to health outcomes is limited, which impedes their widespread dissemination. We examined how the receipt of enabling services influenced patient health care outcomes based on a nationally representative survey of patients served in 2014 at health centers funded by the Health Resources and Services Administration. We compared enabling services users and nonusers and found that enabling services were associated with 1.92 more health center visits, an 11.78-percentage-point higher probability of getting a routine checkup, a 16.34-percentage-point higher likelihood of having had a flu shot, and a 7.63-percentage-point higher probability of patient satisfaction. Our results confirm the value of systematic delivery of enabling services in reducing access barriers and improving patient satisfaction.

4.
Sleep Breath ; 2019 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-31473914

RESUMO

PURPOSE: Obstructive sleep apnea syndrome (OSAS) was suggested to exert an effect on renal function. However, the specific mechanism was still unknown. We try to find the association among OSAS, adiponectin, and cystatin C and the effect of adiponectin on renal function in OSAS patients. METHODS: Seventeen healthy men and seventy-three men which only had OSAS were included in the end. Apnea-hypopnea index (AHI), oxygen desaturation index (ODI), the percentage of total sleep time spent with SpO2 < 90% (T90%), lowest O2 saturation (LaSO2), Epworth Sleepiness Scale (ESS) score, serum adiponectin, and high-sensitive C-reactive protein (hsCRP) were detected in all subjects, and renal function was evaluated with creatinine, cystatin C, and estimated glomerular filtration rate (eGFR). RESULTS: Demographic data, creatinine, and eGFR did not differ among the studied groups. Decreased serum adiponectin levels were associated with severe OSAS. OSAS patients had a higher hsCRP and cystatin C than those without OSAS. Serum adiponectin levels had a negative association with cystatin C. After adjusted for confounders, adiponectin, hsCRP, and ODI had a significant prediction on the cystatin C (ß = - 0.218, p = 0.011; ß = 0.226, p = 0.037; and ß = 0.231, p = 0.029). CONCLUSIONS: Decreased serum adiponectin was associated with increased cystatin C in male OSAS patients. These results suggest that serum adiponectin might be a regulatory factor for renal function in OSAS.

5.
J Vis Exp ; (150)2019 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-31475992

RESUMO

We herein present a method for the synthesis of HNbWO6, HNbMoO6, HTaWO6 solid acid nanosheet modified Pt/CNTs. By varying the weight of various solid acid nanosheets, a series of Pt/xHMNO6/CNTs with different solid acid compositions (x = 5, 20 wt%; M = Nb, Ta; N = Mo, W) have been prepared by carbon nanotube pretreatment, protonic exchange, solid acid exfoliation, aggregation and finally Pt particles impregnation. The Pt/xHMNO6/CNTs are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and NH3-temperature programmed desorption. The study revealed that HNbWO6 nanosheets were attached on CNTs, with some edges of the nanosheets being bent in shape. The acid strength of the supported Pt catalysts increases in the following order: Pt/CNTs < Pt/5HNbWO6/CNTs < Pt/20HNbMoO6/CNTs < Pt/20HNbWO6/CNTs < Pt/20HTaWO6/CNTs. In addition, the catalytic hydroconversion of lignin-derived model compound: diphenyl ether using the synthesized Pt/20HNbWO6 catalyst has been investigated.

6.
J Neuroinflammation ; 16(1): 175, 2019 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-31472680

RESUMO

BACKGROUND AND PURPOSE: Regulation of neural inflammation is considered as a vital therapeutic target in ischemic stroke. All-trans retinoic acid (atRA), a potent immune modulator, has raised interest in the field of stroke therapy. However, the immunological mechanisms for atRA-mediated neuroprotection remain elusive. The current study evaluated the impact of atRA on post-stroke neural inflammation and elucidated the mechanisms involved in the regulation of related neutrophil functions. METHODS: atRA was prophylactically administered to mice 1 day before transient middle cerebral artery occlusion (tMCAO, 1 h) and repeated daily immediately after reperfusion for 3 days. Stroke outcomes, neutrophil polarization, and formation of neutrophil extracellular traps (NETs) in the stroke lesion were assessed. Neutrophil depletion was induced with anti-Ly6G antibodies. Primary neutrophil cultures were used to explore the mechanisms of atRA treatment. RESULTS: Prophylactic atRA treatment reduced infarct volumes and neurological deficits at 1 day after tMCAO. Post-stroke neural inflammation was attenuated and neutrophil accumulation in lesion was downregulated. atRA treatment skewed neutrophil toward N2 phenotype which facilitated its clearance by macrophage and inhibited NETs formation. The functions of neutrophil were indispensable in the protective effects of atRA and were associated with suppression to STAT1 signaling by atRA. Administration of atRA after stroke still provided efficient protection to cerebral ischemia. CONCLUSION: atRA displays potent therapeutic efficacy in ischemic stroke by attenuating neural inflammation. Treatment of atRA impeded neutrophil accumulation, favored N2 polarization, and forbade NETs formation in ischemic lesion. STAT1 signaling played a decisive role in the mechanisms of atRA-afforded regulation to neutrophil.

7.
ACS Nano ; 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31490650

RESUMO

Biofilm infections can induce chronic inflammation and stall the normal orchestrated course of wound-healing cascades. Herein, pH-switchable antimicrobial hydrogel with nanofiber networks for biofilm eradication and rescuing stalled healing in chronic wounds is reported on the basis of the self-assembly of a designed octapeptide (IKFQFHFD) at neutral pH. This hydrogel is biocompatible and exhibits an acidic pH (pathological environment of infected chronic wounds)-switchable broad-spectrum antimicrobial effect via a mechanism involving cell wall and membrane disruption. The antimicrobial activity of hydrogel is derived from its acidic pH-dependent nanofiber network destabilization and activated release of IKFQFHFD, which is antimicrobial only at acidic pH due to the antimicrobial peptide-like molecular structure. In addition, supramolecular nanofiber networks loaded with drugs of cypate (photothermal agent) and proline (procollagen component) are further developed. In vitro experiments show that loaded drugs exhibit acidic pH (pH ∼ 5.5)-responsive release profiles, and synergistic biofilm eradication and subsequent healing cascade activation of cells proliferation are achieved on the basis of the supramolecular nanofiber networks. Remarkably, the nanofiber networks of hydrogel enable in vivo complete healing of MRSA biofilm infected wound in diabetic mice within 20 days, showing great potential as promising chronic wound dressings. The proposed synergistic strategy for eradicating biofilm and activating subsequent healing cascades may offer a powerful modality for the management of clinical chronic wounds.

8.
Microvasc Res ; : 103923, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31494123

RESUMO

Minimally modified low-density lipoprotein (mmLDL) is a risk factor for cardiovascular disease. This study was designed to investigate the effect of a Toll-like receptor 4 monoclonal antibody (TLR4 mAb) on mmLDL-induced endothelium-dependent vasodilation (EDV) impairment in mouse mesenteric arteries and to explore the underlying mechanism. Animals were divided into a normal control group, an mmLDL treatment group, and a TLR4 mAb intervention group. The serum concentrations of IL-1ß and TNF-α were detected using enzyme-linked immunosorbent assays (ELISAs). EDV function was measured using a microvascular tension tracing method. The protein levels and mRNA expression of IL-1ß and TNF-α in vascular tissue were detected using western blot analysis and reverse transcription polymerase chain reaction, respectively. TLR4 mAb improved mmLDL-induced EDV functional impairment in a dose-dependent manner. TLR4 mAb significantly upregulated KCa3.1 and KCa2.3 channel protein levels and downregulated TNF-α and IL-1ß expression. These effects were possibly associated with the competitive antagonism of TLR4 mAb on the TLR4 signaling pathway and the downstream NF-κB p65 and p38 MAPK pathways, which are activated by mmLDL. In conclusion, pretreatment with TLR4 mAb lessens mmLDL-induced EDV dysfunction and inhibits overexpression of inflammatory factors. Regulation of the TLR4 pathway, as well as its downstream NF-κB p65 and p38 MAPK pathways, may be an effective strategy for the prevention and treatment of cardiovascular diseases.

9.
Acta Physiol (Oxf) ; : e13374, 2019 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-31495066

RESUMO

AIM: Apoptosis of vascular smooth muscle cells (VSMCs) influenced by abnormal cyclic stretch is crucial for vascular remodeling during hypertension. Lamin A/C, a nuclear envelope protein, is mechano-responsive, but the role of lamin A/C in VSMC apoptosis is still unclear. METHODS: FX-5000T Strain Unit provided cyclic stretch (CS) in vitro. AnnexinV/PI and cleaved Caspase 3 ELISA detected apoptosis. qPCR was used to investigate expression of miR-124-3p and a luciferase reporter assay was used to evaluate the ability of miR-124-3p binding to the Lmna 3'UTR. Protein changes of lamin A/C and relevant molecules were detected by western blot. Ingenuity Pathway Analysis and Protein/DNA array detected the potential transcription factors. Renal hypertensive rats verified these changes. RESULTS: High cyclic stretch (15%-CS) induced VSMC apoptosis and repressed lamin A/C expressions compared with normal (5%-CS) control. Downregulation of lamin A/C enhanced VSMC apoptosis. In addition, 15%-CS had no significant effect on mRNA expression of Lmna, and lamin A/C degradation was not induced by autophagy. 15%-CS elevated miR-124-3p, which bound to 3'UTR of Lmna, and then negatively regulated protein expression of lamin A/C. Similar changes occurred in renal hypertensive rats compared with sham controls. Lamin A/C repression affected activity of TP53, CREB1, MYC, STAT1/5/6 and JUN, which may in turn affect apoptosis. CONCLUSION: Our data suggested that the decreased expression of lamin A/C upon abnormal cyclic stretch and hypertension may induce VSMC apoptosis. These mechano-responsive factors play important roles in VSMC apoptosis and might be novel therapeutic targets for vascular remodeling in hypertension. This article is protected by copyright. All rights reserved.

10.
Chem Commun (Camb) ; 2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31495834

RESUMO

It is challenging to endow polymorphs with both long-term stability and easy interconvertibility. We demonstrate an interesting example that two room-temperature polymorphs could be long-term stable yet easily interconvertible, at a pressure of ∼4.8 MPa and a temperature of 120 °C, by switching hydrogen bonds via collective reorientation of organic cations in chiral molecular perovskites.

11.
Adv Mater ; : e1903813, 2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31497898

RESUMO

Lithium-sulfur (Li-S) batteries hold great promise to serve as next-generation energy storage devices. However, the practical performances of Li-S batteries are severely limited by the sulfur cathode regarding its low conductivity, huge volume change, and the polysulfide shuttle effect. The first two issues have been well addressed by introducing mesoporous carbon hosts to the sulfur cathode. Unfortunately, the nonpolar nature of carbon materials renders poor affinity to polar polysulfides, leaving the shuttling issue unaddressed. In this contribution, atomic cobalt is implanted within the skeleton of mesoporous carbon via a supramolecular self-templating strategy, which simultaneously improves the interaction with polysulfides and maintains the mesoporous structure. Moreover, the atomic cobalt dopants serve as active sites to improve the kinetics of the sulfur redox reactions. With the atomic-cobalt-decorated mesoporous carbon host, a high capacity of 1130 mAh gS -1 at 0.5 C and a high stability with a retention of 74.1% after 300 cycles are realized. Implanting atomic metal in mesoporous carbon demonstrates a feasible strategy to endow nanomaterials with targeted functions for Li-S batteries and broad applications.

12.
Elife ; 82019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31478830

RESUMO

Gene copy number alterations, tumor cell stemness, and the development of platinum chemotherapy resistance contribute to high-grade serous ovarian cancer (HGSOC) recurrence. Stem phenotypes involving Wnt-ß-catenin, aldehyde dehydrogenase activities, intrinsic platinum resistance, and tumorsphere formation are here associated with spontaneous gains in Kras, Myc and FAK (KMF) genes in a new aggressive murine model of ovarian cancer. Adhesion-independent FAK signaling sustained KMF and human tumorsphere proliferation as well as resistance to cisplatin cytotoxicity. Platinum-resistant tumorspheres can acquire a dependence on FAK for growth. Accordingly, increased FAK tyrosine phosphorylation was observed within HGSOC patient tumors surviving neo-adjuvant chemotherapy. Combining a FAK inhibitor with platinum overcame chemoresistance and triggered cell apoptosis. FAK transcriptomic analyses across knockout and reconstituted cells identified 135 targets, elevated in HGSOC, that were regulated by FAK activity and ß-catenin including Myc, pluripotency and DNA repair genes. These studies reveal an oncogenic FAK signaling role supporting chemoresistance.

13.
Sensors (Basel) ; 19(18)2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31487875

RESUMO

Helmet comfort has always been important for the evaluation of infantry equipment accessories and has for decades not been well addressed. To evaluate the stability and comfort of the helmet, this paper proposes a novel type of helmet comfort measuring device. Conventional pressure measuring devices can measure the pressure of flat surfaces well, but they cannot accurately measure the pressure of curved structures with large curvatures. In this paper, a strain-resistive flexible sensor with a slice structure was used to form a matrix network containing more than a 100 sensors that fit the curved surface of the head well. Raw data were collected by the lower computer, and the original resistance value of the pressure was converted from analog to digital by the A/D conversion circuit that converts an analog signal into a digital signal. Then, the data were output to the data analysis and image display module of the upper computer. The complex curved surface of the head poses a challenge for the appropriate layout design of a head pressure measuring device. This study is expected to allow this intuitive and efficient technology to fit other wearable products, such as goggles, glasses, earphones and neck braces.

14.
Zhongguo Dang Dai Er Ke Za Zhi ; 21(9): 890-893, 2019 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-31506148

RESUMO

OBJECTIVE: To study the long-term clinical effect of the CCLG-ALL2008 regimen in the treatment of children newly diagnosed with acute lymphoblastic leukemia (ALL) with different molecular biological features. METHODS: A total of 940 children who were newly diagnosed with ALL were enrolled in this study. The children were treated with the CCLG-ALL2008 regimen. A retrospective analysis was performed for the long-term outcome of ALL children with different molecular biological features. RESULTS: Among the 940 children with ALL, there were 570 boys and 370 girls, with a median age of onset of 5 years (range 1-15 years) and a median follow-up time of 65 months (range 3-123 months). The complete response (CR) rate was 96.7%, the predicted 10-year overall survival (OS) rate was 76.5%±1.5%, and the event-free survival (EFS) rate was 62.6%±3.0%. After CR was achieved after treatment, the overall recurrence rate was 21.9%. The children with positive ETV6-RUNX1 had the lowest recurrence rate and were prone to late recurrence, and those with positive MLL rearrangement had the highest recurrence rate and were prone to early recurrence. The children with positive ETV6-RUNX1 had a significantly higher predicted 10-year OS rate than those with positive TCF3-PBX1, BCR-ABL, or MLL rearrangement and those without molecular biological features (P<0.05). The children with positive ETV6-RUNX1 had a significantly higher predicted 10-year EFS rate than those with positive BCR-ABL or MLL rearrangement (P<0.05). CONCLUSIONS: Molecular biological features may affect the long-term prognosis of children with ALL, and positive MLL rearrangement and BCR-ABL fusion gene are indicators of poor prognosis. Children with positive ETV6-RUNX1 fusion gene have the highest long-term survival rate.

15.
J Agric Food Chem ; 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31508953

RESUMO

High-order multiple emulsions are of great interest in both fundamental research and industrial applications as vehicles for their encapsulation capability of actives. In this work, we report a hierarchically multicompartmental triple emulsion in highly stable by the emulsifying and assembling of natural Quillaja saponin. Water-in-oil-in-(oil-in-water) (W2/O2/(O1/W1)) triple emulsion was confirmed that the compartmented system was consisted of surfaced saponin-coated nanodroplets (SNDs) and dispersed oil globules which in turn contain smaller aqueous droplets. The effects of formulation parameters, including lipophilic emulsifier content, oil fraction and SNDs concentration, on the formation of multiple emulsions were systematically investigated. The assembled into fibrillar network of SNDs at the outer oil-water interface was effectively protect the triple emulsion droplets against flocculation and coalescence, and strongly prevent the osmotic-driven water diffusion between the internal water droplets and the external water phase, thus contributing to a superior stability during a 180 d storage. All those characteristics make the multi-compartmentalized emulsions can be used to co-encapsulate a hydrophilic bioactive (gardenia blue) and two hydrophobic bioactives (eapsanthin and curcumin) in a single emulsion droplet hierarchically for the segregation and protection of multiple cargos. This approach offers promising a route toward accessing the next generation of functional deliveries and encapsulation strategies.

16.
Chem Asian J ; 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31503382

RESUMO

Molecular optical-dielectric duple bistable switches are photoelectric (dielectric and fluorescent) multifunctional material that can simultaneously convert optical and electrical signals in one device for seamless integration. However, exploring optical-dielectric duple channels of dielectric and photoluminescence is still a bigger challenge than single dielectric or photoluminescence bistable ones, which was hardly reported but will be heavily researched owing to the new generation artificial intelligence development needs in the future. Herein, a new optical-dielectric duple bistable switches material, [(CH 3 ) 3 NCH 2 CH 3 ] 2 MnCl 4 ( I ), was obtained by simple method for volatilization of solvent. Variable temperature single crystal X-ray analysis indicates that material I have a reversible bistable structure (order-disorder structure phase transition) corresponding to switching ''ON'' and ''OFF''. Unlike the single dielectric bistable structures were previously reported, material I also own bistable feature in terms of fluorescence property. This material enriches the specific examples of photoelectric duple function switch materials and facilitates the development of required devices.

17.
Nature ; 573(7773): 281-286, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31485078

RESUMO

Enzymes that catalyse CpG methylation in DNA, including the DNA methyltransferases 1 (DNMT1), 3A (DNMT3A) and 3B (DNMT3B), are indispensable for mammalian tissue development and homeostasis1-4. They are also implicated in human developmental disorders and cancers5-8, supporting the critical role of DNA methylation in the specification and maintenance of cell fate. Previous studies have suggested that post-translational modifications of histones are involved in specifying patterns of DNA methyltransferase localization and DNA methylation at promoters and actively transcribed gene bodies9-11. However, the mechanisms that control the establishment and maintenance of intergenic DNA methylation remain poorly understood. Tatton-Brown-Rahman syndrome (TBRS) is a childhood overgrowth disorder that is defined by germline mutations in DNMT3A. TBRS shares clinical features with Sotos syndrome (which is caused by haploinsufficiency of NSD1, a histone methyltransferase that catalyses the dimethylation of histone H3 at K36 (H3K36me2)8,12,13), which suggests that there is a mechanistic link between these two diseases. Here we report that NSD1-mediated H3K36me2 is required for the recruitment of DNMT3A and maintenance of DNA methylation at intergenic regions. Genome-wide analysis shows that the binding and activity of DNMT3A colocalize with H3K36me2 at non-coding regions of euchromatin. Genetic ablation of Nsd1 and its paralogue Nsd2 in mouse cells results in a redistribution of DNMT3A to H3K36me3-modified gene bodies and a reduction in the methylation of intergenic DNA. Blood samples from patients with Sotos syndrome and NSD1-mutant tumours also exhibit hypomethylation of intergenic DNA. The PWWP domain of DNMT3A shows dual recognition of H3K36me2 and H3K36me3 in vitro, with a higher binding affinity towards H3K36me2 that is abrogated by TBRS-derived missense mutations. Together, our study reveals a trans-chromatin regulatory pathway that connects aberrant intergenic CpG methylation to human neoplastic and developmental overgrowth.

18.
Chemosphere ; 239: 124668, 2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31494325

RESUMO

Nitrite is one of major environmental pollutants that can impact immunological parameters in aquatic organisms. In the present study, we investigated the effects of nitrite exposure on oxidative stress, DNA damage and apoptosis in mud crab (Scylla paramamosain). Mud crab were exposed to 0, 5, 10 and 15 mg L-1 nitrite for 72 h. These data showed that acid phosphatase (ACP) and alkaline phosphatase (ALP) activity significantly decreased in treatments with various concentrations of nitrite (5, 10 and 15 mg L-1) after 24 and 48 h, while the levels of nitric oxide (NO) significantly increased in these treatments. Nitrite exposure could suppress superoxide dismutase (SOD) and catalase (CAT) activity, and increase the formation of malondialdehyde (MDA) after 48 and 72 h of exposure. In addition, nitrite exposure decreased total haemocyte counts after 48 and 72 h of exposure. Cytological damage, DNA damage and apoptosis was observed obviously at 72 h after nitrite exposure. Moreover, nitrite exposure significantly induced the mRNA levels of phosphorylated Jun N-terminal kinases (JNK), and eventually activated p53 signaling and caspase-3. These results indicated that nitrite exposure could induce oxidative stress, which further caused DNA damage and apoptosis in mud crab. Our results will be helpful to understand the mechanism of nitrite toxicity on crustaceans.

19.
Mater Sci Eng C Mater Biol Appl ; 104: 109926, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499938

RESUMO

Despite of technical advancements in design and development of new biomaterials, device-related infections continue to occur and can be life-threatening. Differing from existing research work pertaining to introducing antibacterial function upon device surface, this study attempts to address such germ-infection issues through controlled release of antibacterial species from bulk gallium (Ga) and strontium (Sr) containing magnesium (Mg) alloys. To validate such a conceptual framework, Mg alloys containing micro-level concentrations of Ga and/or Sr (0.1 wt%) are employed as model materials, along with commercially pure Mg and titanium (Ti) as control groups. Biodegradation progress of such metal specimens is examined through pH and mass loss measurements, and inductively coupled plasma - atomic emission spectrometry (ICP-AES) as a function of immersion time in Trypticase Soy Broth (TSB) solution under physiological conditions. In vitro biocompatibility and antibacterial performance are characterised through MTT proliferation assay with human mesenchymal stem cells (hMSCs) and the spread plate method with three representative bacterial strains, i.e. S. aureus (ATCC 43300), E. coli (ATCC 25922), and S. epidermidis (ATCC 35984). Animal tests are performed through implanting target metal rods into femurs of Sprague Dawley rats, accompanied with injection of S. aureus to build a model of osteomyelitis. Results demonstrate that such lean additions of Ga and/or Sr reduce the degradation kinetics of Mg matrix, and the release of Ga3+ ions plays a crucial role in disabling the viability of all selected bacterial strains. The histological tests confirm that the growth of fibrous tissue has been accelerated in the vicinity of Mg-based implants, in comparison to that of blank and c.p. Ti controls. It is also striking that the smallest number density of S. aureus bacteria on the surface of the retrieved Ga-containing Mg rod implants. Such a proof-of-concept study provides a new and feasible strategy to address the notorious device-infection issues associated with biomedical implants for bone fracture management.

20.
Metabolites ; 9(9)2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31487917

RESUMO

The authors wish to make the following corrections to this paper [...].

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