水凝胶负载pVAX1-SpaP/P防龋DNA疫苗以4种途径产生免疫效应

背景:防龋DNA疫苗价格低廉、安全有效,有望成为人类抵抗龋病的重要手段,因而学者在寻找一种能高效诱导抗体产生的免疫途径或保护疫苗效价的缓释系统及佐剂,成为近年研究的热点.目的:观察聚乳酸乙醇酸-聚乙二醇-聚乳酸乙醇酸水凝胶负载pVAX1-SpaP/P防龋基因疫苗的免疫效应.方法:以聚乳酸乙醇酸-聚乙二醇-聚乳酸乙醇酸水...     

人工软骨材料——聚乙烯醇水凝胶的研制

聚乙烯醇溶液于－２０℃左右的温度下冷冻６－１２ｈ,室温下颌化１－２ｈ,上述过程反复进行１－３次,然后对试样进行真空脱水处理,制得一种人工软骨材料－ＰＶＡ水凝胶。     

Promotion of cardiac differentiation of brown adipose derived stem cells by chitosan hydrogel for repair after myocardial infarction

The ability to restore heart function by replacement of diseased myocardium is one of the great challenges in biomaterials and regenerative medicine. Brown adipose derived stem cells (BADSCs) present a new source of cardiomyocytes to regenerate the myocardium after infarction. In this study, we explored an injectable tissue engineering strategy to repair damaged myocardium, in which chitosan hydrogels were investigated as a carrier for BADSCs. In vitro, the effect and mechanism of chitosan components on the cardiac differentiation of BADSCs were investigated. In vivo, BADSCs carrying double-fusion reporter gene (firefly luciferase and monomeric red fluorescent protein (fluc-mRFP)) were transplanted into infarcted rat hearts with or without chitosan hydrogel. Multi-techniques were used to assess the effects of treatments. We observed that chitosan components significantly enhanced cardiac differentiation of BADSCs, which was assessed by percentages of cTnT⁺ cells and expression of cardiac-specific markers, including GATA-4, Nkx2.5, Myl7, Myh6, cTnI, and Cacna1a. Treatment with collagen synthesis inhibitors, cis-4-hydroxy-d-proline (CIS), significantly inhibited the chitosan-enhanced cardiac differentiation, indicating that the enhanced collagen synthesis by chitosan accounts for its promotive role in cardiac differentiation of BADSCs. Longitudinal in vivo bioluminescence imaging and histological staining revealed that chitosan enhanced the survival of engrafted BADSCs and significantly increased the differentiation rate of BADSCs into cardiomyocytes in vivo. Furthermore, BADSCs delivered by chitosan hydrogel prevented adverse matrix remodeling, increased angiogenesis, and preserved heart function. These results suggested that the injectable cardiac tissue engineering based on chitosan hydrogel and BADSCs is a useful strategy for myocardium regeneration.     

可注射智能壳聚糖水凝胶的研究进展

本文简要介绍了以壳聚糖或其衍生物为原料制备的可注射智能水凝胶的研究进展、应用以及尚待解决的问题,探讨其作为生物医药高分子材料的前景.     

Incorporation of magnesium ions into photo‐crosslinked alginate hydrogel enhanced cell adhesion ability

Photo‐crosslinked alginate hydrogel attracts wide interest in tissue engineering because of its excellent controllability and stability. However, its highly hydrophilic property makes cell adhesion difficult. Plenty of studies have confirmed that magnesium ions (Mg²⁺) can efficiently improve the attachment of osteoblasts. In this study, for the first time, we fabricated a durable, crosslinked, alginate hydrogel with a dual‐crosslinking network. Photo‐crosslinked alginate hydrogel was chosen as the basic backbone, and various amounts of Mg²⁺ were incorporated into the hydrogel through ionic crosslinking. The results showed that the physicochemical properties of the hydrogels, including surface structure, composition, swelling ratio, ion release and elastic modulus, could be well tuned by controlling the amount of Mg²⁺ incorporated. In addition, a certain amount of Mg²⁺ significantly improved the attachment and spread of osteoblasts on the hydrogels. These characteristics make Mg²⁺‐incorporated photo‐crosslinked alginate hydrogel a promising scaffold for bone tissue engineering. Copyright © 2015 John Wiley & Sons, Ltd.     

Point‐of‐care treatment of focal cartilage defects with selected chondrogenic mesenchymal stromal cells—An in vitro proof‐of‐concept study

Due to the poor self‐healing capacities of cartilage, innovative approaches are a major clinical need. The use of in vitro expanded mesenchymal stromal cells (MSCs) in a 2‐stage approach is accompanied by cost‐, time‐, and personnel‐intensive good manufacturing practice production. A 1‐stage intraoperative procedure could overcome these drawbacks. The aim was to prove the feasibility of a point‐of‐care concept for the treatment of cartilage lesions using defined MSC subpopulations in a collagen hydrogel without prior MSC monolayer expansion. We tested 4 single marker candidates (MSCA‐1, W4A5, CD146, CD271) for their effectiveness of separating colony‐forming units of ovine MSCs via magnetic cell separation. The most promising surface marker with regard to the highest enrichment of colony‐forming cells was subsequently used to isolate a MSC subpopulation for the direct generation of a cartilage graft composed of a collagen type I hydrogel without the propagation of MSCs in monolayer. We observed that separation with CD271 sustained the highest enrichment of colony‐forming units. We then demonstrated the feasibility of generating a cartilage graft with an unsorted bone marrow mononuclear cell fraction and with a characterized CD271 positive MSC subpopulation without the need for a prior cell expansion. A reduced volume of 6.25% of the CD271 positive MSCs was needed to achieve the same results regarding chondrogenesis compared with the unseparated bone marrow mononuclear cell fraction, drastically reducing the number of nonrelevant cells. This study provides a proof‐of‐concept and reflects the potential of an intraoperative procedure for direct seeding of cartilage grafts with selected CD271 positive cells from bone marrow.     

Development and characterization of novel agar and gelatin injectable hydrogel as filler for peripheral nerve guidance channels

Injectable hydrogels are becoming of increasing interest in the field of tissue engineering thanks to their versatile properties and to the possibility of being injected into tissues or devices during surgery. In peripheral nerve tissue engineering, injectable hydrogels having shear‐thinning properties are advantageous as filler of nerve guidance channels (NGCs) to improve the regeneration process. In the present work, gelatin‐based hydrogels were developed and specifically designed for the insertion into the lumen of hollow NGCs through a syringe during surgery. Injectable hydrogels were obtained using an agar–gelatin 20:80 weight ratio, (wt/wt) blend crosslinked by the addition of genipin (A/GL_GP). The physicochemical properties of the A/GL_GP hydrogels were analysed, including their injectability, rheological, swelling and dissolution behaviour, and their mechanical properties under compression. The hydrogel developed showed shear‐thinning properties and was applied as filler of NGCs. The A/GL_GP hydrogel was tested in vitro using different cell lines, among them Schwann cells which have been used because they have an important role in peripheral nerve regeneration. Viability assays demonstrated the lack of cytotoxicity. In vitro experiments showed that the hydrogel is able to promote cell adhesion and proliferation. Two‐ and three‐dimensional migration assays confirmed the capability of the cells to migrate both on the surface and within the internal framework of the hydrogel. These data show that A/GL_GP hydrogel has characteristics that make it a promising scaffold material for tissue engineering and nerve regeneration. Copyright © 2014 John Wiley & Sons, Ltd.     

聚丙烯酰胺水凝胶注射隆乳的清除

目的聚丙烯酰胺凝胶注射隆乳后广泛采用抽吸游离凝胶的方法,仍有相当一部分注射物残留。本文阐述并探讨聚丙烯酰胺水凝胶隆乳后清除的方法。方法 2005年2月至2013年12月,共170位曾注射聚丙烯酰胺水凝胶隆乳的患者要求去除注射物。我们使用乳晕下边缘切口,尽可能清除游离注射物,然后沿注射物外部的包囊进行分离,尽可能地去除浸润变性的包囊和筋膜组织。结果除5位患者对术后乳房较为平坦的外观不满以外,其余绝大部分患者对术后效果表示满意。乳房包块、疼痛、上肢活动不适感及乳房手感变硬等并发症都减轻或消失。结论为解决注射隆乳术后乳房包块、疼痛及乳房偏硬造成的上肢活动不适等并发症,尽可能地去除游离凝胶及浸润有凝胶的周围组织,才能获得较为理想的效果,我们推荐采用将游离的凝胶及浸润周围包囊和/或筋膜一起去除的方法。     

新型氧气湿化输送系统的研制与临床应用

目的保证氧疗效果,解决氧气湿化过程中普遍存在的湿化液污染及湿化产生噪声问题。方法将172例需吸氧的肺癌患者随机分为观察组和对照组各86例,观察组应用自行研制的新型氧气湿化输送系统吸氧,对照组使用传统氧气湿化输送系统吸氧。结果观察组仅1例患者主观感受到湿化噪声,与对照组比较,差异有统计学意义（P〈0．01）;观察组湿化单元细菌培养阳性率显著低于对照组（P〈0．01）。结论新型氧气湿化输送系统应用于临床氧疗,能降低传统氧气湿化液污染导致的医院呼吸道感染的风险,降低噪声,可保证患者休息,且不影响氧疗效果。     

明胶-聚异丙基丙烯酰胺水凝胶的溶胀动力学

采用明胶（Gel)和N－异丙基丙烯酰胺（NIPAM）为原料，制备了Gel/聚异丙基丙烯酰胺（PNIPAM）水凝胶系列；研究了原料配比、pH值及温度对水凝胶溶胀速度的影响。结果表明，当温度大于PNIPAM的最低临界溶液温度（LCST）值时，Gel/PNIPAM水凝胶的溶胀速度随着组分中PNIPAM的增加而降低，且溶胀过程以扩散渗透控制为主。而pH对水凝胶溶胀速度的影响与温度有关。Gel/PNIPAM配比为5／5，温度大于LCST时，水凝胶的pH敏感性受明胶控制；温度低于LCST时，pH对水凝胶的溶胀速度的影响很小。