Prevention of postoperative tendon adhesion by biodegradable electrospun membrane of poly(lactide-co-glycolide)

An electrospun poly(lactide-co-glycolide)(PLGA) membrane was prepared and used to perform the anti-adhesion of Achilles tendon. Throughout the experiments, the membrane showed an appropriate degradation rate, and the p H values of degradation media were maintained at around 7.4. Simultaneously, the excellent biocompatibility of the membrane in vitro and in vivo was confirmed by live/dead and histopathological analyses. Meanwhile, the membrane can reduce tendon adhesion significantly and promote functional recovery effectively. The encouraging results were further demonstrated by hematoxylin and eosin(HE), and Masson's trichrome stainings, and type I collagen immunohistochemical analysis. It was concluded that the model treated with the electrospun PLGA membrane was significantly better with respect to the adhesion prevention and tissue repair than that without treatment. Considering the results of degradation and adhesion prevention efficacy, the electrospun PLGA membrane would be a great candidate for the prevention of postoperative tendon adhesion.     

Surface modification of PDMS by surface-initiated atom transfer radical polymerization of water-soluble dendronized PEG methacrylate

The current paper reports the synthesis of a highly hydrophilic, antifouling dendronized poly(3,4,5-tris(2-(2-(2-hydroxylethoxy)ethoxy)ethoxy)benzyl methacrylate) (PolyPEG) brush using surface initiated atom transfer radical polymerization (SI-ATRP) on PDMS substrates. The PDMS substrates were first oxidized in H₂SO₄/H₂O₂ solution to transform the Si-CH₃ groups on their surfaces into Si-OH groups. Subsequently, a surface initiator for ATRP was immobilized onto the PDMS surface, and PolyPEG was finally grafted onto the PDMS surface via copper-mediated ATRP. Various characterization techniques, including contact angle measurements, attenuated total reflection infrared spectroscopy, and X-ray photoelectron spectroscopy, were used to ascertain the successful grafting of the PolyPEG brush onto the PDMS surface. Furthermore, the wettability and stability of the PDMS-PolyPEG surface were examined by contact angle measurements. Anti-adhesion properties were investigated via protein adsorption, as well as bacterial and cell adhesion studies. The results suggest that the PDMS-PolyPEG surface exhibited durable wettability and stability, as well as significantly anti-adhesion properties, compared with native PDMS surfaces. Additionally, our results present possible uses for the PDMS-PolyPEG surface as adhesion barriers and anti-fouling or functional surfaces in biomedical applications.     

Modification of membrane surface for anti-biofouling performance: Effect of anti-adhesion and anti-bacteria approaches

Membrane biofouling refers to the undesirable accumulation (attachment and growth) of microorganisms on a membrane surface, and has been a major problem in the application of membrane technology in water and wastewater treatment. In this study, the surface of a base membrane made of chitosan/cellulose acetate blend was modified by reacting with heparin, quaternary ammonium or being immobilized with silver ions. The purpose of the modifications was to increase the surface hydrophilicity, alter the surface charge property or endue the surface with anti-bacteria function. The modified membranes were then examined for their anti-biofouling performance in terms of the anti-adhesion and anti-bacteria effects, with Escherichia coli pure culture and mixed culture bacteria in a bioreactor that simulated the activated sludge wastewater treatment process. The results clearly show that the hydrophilicity of a membrane, although important, is not an effective indicator for the tendency of membrane biofouling but the nature of the surface charges of the membrane also plays a very important role. It was found that the anti-adhesion approach that prevents the initial attachment of bacteria on a membrane surface is a more effective method than the anti-bacteria approach that aims at killing bacteria already attached on the membrane surface. The best performance for minimizing membrane biofouling has, however, been realized through a modified membrane surface that has effective anti-adhesion property plus additional anti-bacteria function, with the latter as a safe guard in case some bacteria do attach to the surface of a membrane.     

Mucin layers and multilayers — Physicochemical properties and applications

The present review summarizes recent, and important previous, findings on properties of mucin layers and multilayers and ways to tailor their properties. Specifically, progress has been made in understanding the effects of mucin type, preparations, ambient conditions and surface properties on adsorption and on mixed layer assembly including multilayers. Apart from structural features the stability, lubrication and biological functions of such layers are addressed.     

表面抗菌功能涂层的构建及在生物医用材料中的应用研究

近年来,生物医用材料在使用过程中产生的医源性感染问题层出不穷,对人们健康和生命造成严重威胁.表面抗菌涂层构建是解决该类医源性感染问题最有效的策略之一.目前,按照作用机制和功能不同将表面抗菌涂层分为接触式抗菌涂层、抗黏附抑菌涂层、抗黏附杀菌涂层以及智能抗菌涂层.表面抗菌涂层的构建不仅赋予了生物医用材料抗菌性能,有效解决了...     

Preparation and Non-Invasive In-Vivo Imaging of Anti-Adhesion Barriers with Fluorescent Polymeric Marks

Comb-like PEMLn polymers with pendent PEG-PLLA side chains were synthesized as tissue anti-adhesion barriers. The comb-like structure improved the flexibility of the films. Fluorescent polymer-biocompatible polymer guest-host materials were printed on the films as marking dots. Without sacrificing rats on different days after surgery, degradation behaviors of the marked films can be investigated non-invasively in the in-vivo imaging system (IVIS) by monitoring the location of fluorescent signals. Degradation properties of PEML1/G26L35 films were adjusted by incorporating G26L35 oligomers. PEML1 and PEML1/G26L35 films were very effective in preventing post-surgical tissue-adhesions. Degradation behaviors of various films observed in the animal study were consistent with those investigated by the in-vivo imaging method. Fluorescent polymer/biocompatible polymer blends were promising candidates for in-vivo imaging applications.     

利用胶体探针技术研究多巴与纳米、微米及微纳复合结构表面之间的相互作用

通过在硅片表面有机蒸镀不同厚度的二十九烷制备了不同晶体密度的仿生旱金莲叶面蜡质纳米结构表面,采用端基修饰多巴的原子力显微镜胶体探针,对各纳米结构表面进行了粘附性能测试,发现蒸镀200 nm厚度二十九烷结晶的纳米结构表面具有较低粘附力。采用反应离子刻蚀方法制备了不同高度的硅材质仿生鲨鱼皮微米结构表面,并选择了200 nm厚度二十九烷在仿生鲨鱼皮表面进行有机蒸镀制备了微纳复合结构表面,通过胶体探针的研究发现多巴与高度为1、3、5μm微纳复合结构表面的粘附力均小于与200 nm厚度二十九烷结晶的纳米结构表面之间的粘附力,说明微纳复合结构表面具有很强的抗多巴粘附能力,并且这种复合结构表面相对于硅材质的仿生鲨鱼皮微米结构表面还兼有旱金莲叶面的强疏水性和极佳的抗水粘附能力。     

Evaluation of bacterial adhesion on Si-doped diamond-like carbon films

Diamond-like carbon (DLC) films as biomaterial for medical devices have been attracting great interest due to their excellent properties such as hardness, low friction and chemical inertness. It has been demonstrated that the properties of DLC films can be further improved by the addition of silicon into DLC films, such as thermal stability, compressive stress, etc. However no research work on anti-bacterial properties of silicon-doped diamond-like carbon films has been reported. In this paper the surface physical and chemical properties of Si-doped diamond-like carbon films with various Si contents on 316 stainless steel substrate prepared by a magnetron sputtering technique were investigated, including surface topography, surface chemistry, the sp³/sp² ratio, contact angle, surface free energy, etc. Bacterial adhesion to Si-doped DLC films was evaluated with Pseudomonas aeruginosa, Staphylococcus epidermidis and Staphylococcus aureus which frequently cause medical device-associated infections. The experimental results showed that bacterial adhesion decreased with increasing the silicon content in the films. All the Si-doped DLC films performed much better than stainless steel 316L on reducing bacterial attachment.     

Ⅱ度以上宫腔粘连分离术采用不同物理屏障抗粘连疗效分析

目的探讨Ⅱ度以上宫腔粘连分离术采用不同物理屏障抗粘连的临床效果。方法选取212例Ⅱ度以上宫腔粘连患者,其中宫腔粘连分离术留置宫内节育器者作为A组（Ⅱ度47例,Ⅲ度38例,Ⅳ度43例）,宫腔粘连分离术留置宫内球囊后改放置节育器者作为B组（Ⅱ度28例,Ⅲ度30例,Ⅳ度26例）。以上两组术后其他后续治疗方法均一致。术后每28d复查1次,性激素序贯治疗3周期结束后予以宫腔镜下节育器取出术同时行二次探查并登记月经情况。结果（1）月经情况：两组术前月经过少的同度患者相比,月经恢复情况差异无统计学意义（P＞0.05）。术前闭经患者术后月经复潮率89.3%（92/103）。IV度术后月经复潮率B组高于A组,差异有统计学意义（93.8%vs 62.5%,P＜0.05）。（2）并发症发生率及预后情况：宫内节育器嵌顿共12例,A组8例,B组4例,总发生率5.7%,两组之间差异无统计学意义（P＞0.05）。未发现泌尿道生殖道感染病例。宫腔粘连重新形成110例（51.9%）;其中IV度A组高于B组,差异有统计学意义（P＜0.05）。结论对于IV度宫腔粘连行宫腔镜下分离术,术中留置宫内球囊后改宫内节育器将比单独使用宫内节育器有更好的治疗效果。     

Effect of surface roughness and release layer on anti-adhesion performance of the imprint template

UV imprint lithography has been initiated as an enabling, cost-effective technique to achieve 100 nm resolution patterning in recent years. However, the adhesion between resist and imprint template is one of the critical problems for the industrial application of imprint lithography. In this paper, two kinds of measures, including increase of surface roughness of template and application of a fluorinated release agent as self-assembled monolayers (SAMs) to the template surface, were taken to overcome the adhesion between resist and template. The test results of contact angle showed that the appropriate increase of surface roughness could improve hydrophilicity of template surface greatly, and improved the hydrophobicity of template surface when it was combined with self-assembled monolayers. The XPS, DRIR spectra indicated that the fluorinated release layers were successfully prepared on the surface of template using the process in the paper. The surface free energy of the template was 16.6 mN/m, and less than that of PTFE (18 mN/m). The imprint experiment results also showed that the anti-adhesion performance of treated template was improved greatly during detaching procedure, and the demolding force decreased by 56.64% in comparison with that of untreated template.