Collagen type I–PLGA film as an efficient substratum for corneal endothelial cells regeneration

Surface modulations of desired biological construct design for regenerative medical therapy is considered to be highly crucial for cell growth and the subsequent regeneration of biologically competent tissues. In this study, we fabricated stable, transparent, collagen type‐I‐coated PLGA films (Col I–PLGA) as a potential substratum for the regeneration of corneal endothelial cells. Morphological and structural properties were analysed by FE–SEM, AFM, FTIR, contact angle, etc., and in vitro biocompatibility of the Col I–PLGA films was further tested in primary rabbit corneal endothelial cells (rCEnCs) as models. Compared with bare PLGA films, the Col I–PLGA films displayed the requisite surface roughness, with higher Ra (nm) values, transparency, good hydrophilicity, stability and water uptake. Next, cultured rCEnCs on Col I–PLGA films showed the characteristic polygonal shape of rCEnCs with enhanced initial attachment, proliferation and expression of mRNAs. Collectively, these results indicate that Col I–PLGA can be employed as a suitable alternative for high‐quality corneal tissue expansion and transplantation. Copyright © 2016 John Wiley & Sons, Ltd.     

pH-responsive nanoparticles releasing tenofovir intended for the prevention of HIV transmission

This study is designed to test the hypothesis that tenofovir (TNF) or tenofovir disoproxil fumarate (TDF) loaded nanoparticles (NPs) prepared with a blend of poly(lactic-co-glycolic acid) (PLGA) and methacrylic acid copolymer (Eudragit® S-100, or S-100) are noncytotoxic and exhibit significant pH-responsive release of anti-HIV microbicides in the presence of human semen fluid simulant (SFS). After NPs preparation by emulsification diffusion, their size, encapsulation efficiency (EE%), drug release profile, morphology, and cytotoxicity are characterized by dynamic light scattering, spectrophotometry, transmission electron microscopy, and cellular viability assay/transepithelial electrical resistance measurement, respectively. Cellular uptake was elucidated by fluorescence spectroscopy and confocal microscopy. The NPs have an average size of 250 nm, maximal EE% of 16.1% and 37.2% for TNF and TDF, respectively. There is a 4-fold increase in the drug release rate from the 75% S-100 blend in the presence of SFS over 72 h. At a concentration up to 10 mg/ml, the PLGA/S-100 NPs are noncytotoxic for 48 h to vaginal endocervical/epithelial cells and Lactobacillus crispatus. The particle uptake (∼50% in 24 h) by these vaginal cell lines mostly occurred through caveolin-mediated pathway. These data suggest the promise of using PLGA/S-100 NPs as an alternative controlled drug delivery system in intravaginal delivery of an anti-HIV/AIDS microbicide.     

包裹放射性核素131I的高分子纳米药物的制备及其放射自显影实验

目的制备一种包裹放射性核素的纳米药物,并对其理化性质及放射性特征进行研究。方法采用高分子纳米材料聚乳酸/羟基乙酸(PLGA)作为载体,用放射线核素131I作为包裹药物,通过双乳化法和冷冻干燥技术制备包裹131I的PLGA纳米药物。并对其外观、形态及放射性特征进行观察分析,采用光镜、电镜及放射自显影术,检测其粒径、电位及其包裹放射性核素的能力。结果通过本方法成功制备了包裹放射性核素131I的高分子纳米药物;光镜下观察其形态规则、呈球形,大小均匀,平均粒径为(1.55±0.25)μm,电位为(-30.1±5.3)mv;包封率为(1.0±0.5)%;单个PLGA纳米药物的放射性活度约为1.1×10-2 Bq,单个纳米药物的比活度为5.2×10-3 Bq/nm3。体外放射自显影图像显影清晰,与空白对照组对比差异有统计学意义。结论包裹放射性核素131I的纳米放射性微球理化性质稳定,具有较高的包封率,放射性自显影效果好,为对放射性核素抵抗或不敏感的肿瘤核素诊断与治疗提供重要方法和思路,为进一步包裹放射性核素的靶向性纳米药物的研究奠定了基础。     

因子设计-效应面法优化紫杉醇聚乳酸-羟基乙酸纳米粒处方和制备工艺

目的:优化紫杉醇聚乳酸-羟基乙酸(PLGA)纳米粒处方和制备工艺.方法:以PLGA为载体,采用溶剂扩散法制备紫杉醇PLGA纳米粒,用32满因子设计实验,考察因素PLGA在有机相中的浓度和理论载药量对纳米粒的粒径、载药量和包封率的影响,实验数据分别采用线性方程和二次多项式拟合,根据最佳数学模型绘制效应面并选出最优处方.结果:2个影响因素和3个评价指标之间存在定量关系,最优处方为:紫杉醇的理论载药量为9.09%、有机相中PLGA浓度为2%,制备得到的纳米粒粒径为281 nm,实际载药量为7.73%,包封率为57.43%.结论:采用因子设计-效应面法完成了紫杉醇纳米给药系统的多目标同步优化.     

A rabbit model for efficacy evaluation of endovascular coil materials

Background

To investigate biomaterials seeking for their possible use for aneurysm treatment, in vivo screening tests using a number of potential materials are required. However, there is no established animal model that is suitable for such purpose. Some models require special preparation of tested materials for transcatheter delivery and others are inappropriate in view of their cost-effectiveness. The purpose of this study is to establish an animal model that overcomes these limitations and help us select potential materials before the preclinical evaluation.

Methods

Bilateral CCAs in a rabbit were surgically ligated, and a 2-cm segment of either a bare platinum coil or a polymeric coil (a platinum coil coated with PLGA 10/90) was implanted into each blind-ended arterial segment (n = 26). They were harvested at day 1, 7, 10, 14, or 30, respectively. Angiographic and histologic evaluations as well as quantitative analysis on the development of the organized thrombus were performed.

Results

One day after the implantation, both platinum and PLGA coils were surrounded by immature thrombus that was induced by blood flow stagnation in the arterial segment. At day 7, minimal thrombus organization was observed around both types of materials. At postimplantation days 10 and 14, fibrocellular responses, the early findings of the thrombus organization process, were observed in both material groups. Such histologic findings were more prominent in the PLGA coil group as compared to the platinum coil group (day 10, P = .051; day 14, P = .011). Well-organized thrombus was observed in both material groups at day 30 without showing statistical difference (P = .12).

Conclusion

Given the cost-effectiveness, the simple material preparation process, and its feasible histologic evaluation methods, this new animal model can be useful in screening other potential biomaterials for the development of new coil devices.     

聚乙交酯-聚丙交酯降解支架复合胎儿脐动脉细胞构建组织工程血管

目的：探讨改良聚乙交酯-聚丙交酯（PLGA）降解支架复合胎儿脐动脉细胞方法构建组织工程血管（TEBV）的可行性。方法：将胎儿脐动脉的平滑肌细胞,内皮细胞种植于国产PLGA血管上并进行培育,观察两种细胞生长情况、检测内皮细胞、平滑肌细胞并测定其功能。结果：培育2mo后,平滑肌细胞,内皮细胞在PLGA血管片上黏附良好,材料组织相容性好。结论：应用PLGA降解支架复合胎儿脐动脉细胞构建组织工程血管的体外培养方法是可行的,PLGA支架有利于细胞生长、分化及功能发挥,动态培养方法培养出的TEBV色泽光亮,厚度均匀,具有良好的弹性。     

多西紫杉醇PLGA/nHA复合微球的制备及体外释放研究

目的 制备多西紫杉醇(DTX)聚乳酸羟基乙酸(PLGA)/纳米羟基磷灰石(nHA)复合微球,研究纳米羟基磷灰石对复合微球的载药量,包封率和体外释放等性质的影响,以及抑制前列腺癌细胞的增长效应.方法 以疏水性抗癌药物多西紫杉醇作为模型药物,采用单乳化溶剂挥发法(S/O/W)制备PLGA/nHA-DTX复合微球,对载药前后的纳米羟基磷灰石进行透射电子显微镜观察和FTIR分析,并采用扫描电镜、激光粒度仪和高效液相色谱对微球的载药量、包封率、粒径及体外释药性质进行研究.结果 FTIR结果 表明纳米羟基磷灰石对多西紫杉醇有较强的吸附作用.PLGA/nHA-DTX复合微球的载药量和包封率分别为3.92%和88.7%,较之单纯的PLGA-DTX微球均有很大的提高.经过体外释放药物突释后,复合微球比单纯PLGA微球的药物释放慢.在第30 d时,复合微球和单纯的PLGA微球累积药物释率放分别为62.40%和72.70%.MTT实验结果 显示PLGA/nHA复合微球对癌细胞增长的抑制效果优于单纯PLGA微球和药物.结论 与单纯的PLGA-DTX微珠相比,由于纳米羟基磷灰石对多西紫杉醇存在较强的吸附作用,使PLGA/nHA-DTX复合微球的载药量和包封率得到了较大的提高,具有更好的药物缓释效果,抑制癌细胞增长的作用更有效.     

Nanoparticle-based targeted drug delivery

Nanotechnology could be defined as the technology that has allowed for the control, manipulation, study, and manufacture of structures and devices in the “nanometer” size range. These nano-sized objects, e.g., “nanoparticles”, take on novel properties and functions that differ markedly from those seen from items made of identical materials. The small size, customized surface, improved solubility, and multi-functionality of nanoparticles will continue to open many doors and create new biomedical applications. Indeed, the novel properties of nanoparticles offer the ability to interact with complex cellular functions in new ways. This rapidly growing field requires cross-disciplinary research and provides opportunities to design and develop multifunctional devices that can target, diagnose, and treat devastating diseases such as cancer. This article presents an overview of nanotechnology for the biologist and discusses the attributes of our novel XPclad^© nanoparticle formulation that has shown efficacy in treating solid tumors, single dose vaccination, and oral delivery of therapeutic proteins.     

Dexamethasone-containing biodegradable superparamagnetic microparticles for intra-articular administration: Physicochemical and magnetic properties, in vitro and in vivo drug release

Compared with traditional drug solutions or suspensions, polymeric microparticles represent a valuable means to achieve controlled and prolonged drug delivery into joints, but still suffer from the drawback of limited retention duration in the articular cavity. In this study, our aim was to prepare and characterize magnetic biodegradable microparticles containing dexamethasone acetate (DXM) for intra-articular administration. The superparamagnetic properties, which result from the encapsulation of superparamagnetic iron oxide nanoparticles (SPIONs), allow for microparticle retention with an external magnetic field, thus possibly reducing their clearance from the joint. Two molecular weights of poly(lactic-co-glycolic acid) (PLGA) were used, 12 and 19 kDa. The prepared batches were similar in size (around 10 μm), inner morphology, surface morphology, charge (neutral) and superparamagnetic behaviour. The SPION distribution in the microparticles assessed by TEM indicates a homogeneous distribution and the absence of aggregation, an important factor for preserving superparamagnetic properties. DXM release profiles were shown to be quite similar in vitro (ca. 6 days) and in vivo, using a mouse dorsal air pouch model (ca. 5 days).     

Physico-chemical characterisation of PLGA nanoparticles after freeze-drying and storage

Nanoparticles represent promising carriers for controlled drug delivery. Particle size and size distribution of the particles are important parameters for the in vivo behaviour after intravenous injection and have to be characterised precisely. In the present study, the influence of lyophilisation on the storage stability of poly(d,l lactic-co-glycolic acid) (PLGA) nanoparticles, formulated with several cryoprotective agents, was evaluated. Nanoparticles were prepared by a high pressure solvent evaporation method and freeze-dried in the presence of 1%, 2%, and 3% (m/v) sucrose, trehalose, and mannitol, respectively. Additionally, to all samples containing 3% of the excipients, l-arginine hydrochloride was added in concentrations of 2.1% or 8.4% (m/V). Dynamic light scattering (DLS), analytical ultracentrifugation and transmission electron microscopy (TEM) were used for particle characterisation before and after freeze-drying and subsequent reconstitution. In addition, glass transition temperatures were determined by differential scanning calorimetry (DSC), and the residual moisture of the lyophilisates was analysed by Karl Fischer titration. It was demonstrated that 1% sucrose or 2% trehalose were suitable to maintain particle integrity after reconstitution of lyophilised PLGA nanoparticles. The storage stability study over 3 months showed notable changes in mean particle size, size distribution, and residual moisture content, depending on the composition of the formulation.