负载超顺磁性氧化铁颗粒聚合物纳米囊泡的制备及MR成像

目的 制备负载油性、水性超顺磁性氧化铁(SPIO)颗粒聚合物纳米囊泡,并观察其表征和MRI成像特点.方法 经多步化学反应得到共聚物聚乙二醇-聚(D,L-丙交酯)(PEG-PDLLA),通过多次乳化及溶剂挥散法使共聚物在水溶液中自组装成囊泡,并分别负载油性和水性SPIO.使用扫描电镜和透视电镜观察负载油性、水性SPIO聚合物纳米囊泡的直径、形态、分布,并用MRT2 mapping软件测量单纯SPIO水溶液、负载油性、水性SPIO聚合物纳米囊泡的T2弛豫率(1/T2).溶液浓度分别取原液、原液的1/2、1/4、1/8、1/16、1/32.结果 负载油性SPIO和水性SPIO聚合物纳米囊泡的的平均直径分别为( 182.2 ±23.9) nm、(191.7 ±28.7) nm.电镜显示油性SPIO均匀地分散于囊泡的中心膜上;水性SPIO以团簇的形式被包裹在囊泡的内腔中.负载SPIO的聚合物囊泡比单纯SPIO水溶液表现更高MRI敏感性.在相同铁离子浓度下,负载水性SPIO聚合物囊泡的T2弛豫率(1/8浓度时为4.60)高于负载油性SPIO聚合物纳米囊泡(1/8浓度时为2.85).结论 负载SPIO聚合物纳米囊泡比单纯SPIO水溶液表现出更高的MRI敏感性,负载水性SPIO聚合物囊泡的T2弛豫率高于负载油性SPIO聚合物纳米囊泡.     

温敏型凝胶的缓释作用与临床应用

文题释义：温敏型凝胶：是一种特殊的水凝胶,能根据一定温度从流动的液体(溶胶相)转变为非流动的水凝胶(凝胶相)。因其特性,在生物医学和制药方面有广泛的应用,即药物输送、细胞培养、组织工程等。聚N-异丙基丙烯酰胺：由单体N-异丙基丙烯酰胺聚合而成,其大分子链上同时具有亲水性的酰氨基和疏水性的异丙基,使线型聚N-异丙基丙烯酰胺的水溶液及交联后的聚N-异丙基丙烯酰胺水凝胶呈现温度敏感特性。 背景：温敏型凝胶是近年来兴起的一种药物新剂型,因其具有缓释、控释、靶向给药等优势而成为近年来的研究热点。 目的：总结搜索文献中温敏型凝胶各种缓释机制,以及温敏型凝胶在临床上的应用疗效。 方法：在万方、中国知网、维普、PubMed、谷歌学术等数据库中,以“温敏型凝胶,缓释,给药途径”为中文检索词,以“thermosensitive gel,sustained release,administration route”为英文检索词检索温敏型凝胶缓释机制及临床应用方面的文章。结果与结论：①温敏型凝胶具有最低临界溶解温度,能随环境温度改变而发生一定程度的相变,比其他剂型有更多的优势,能使药物在人体内发挥很好的缓释作用,降低药物毒性,防止药物外渗,并提高药物的稳定性,还具有很好的临床应用前景;②温敏型凝胶有着注射、口腔、耳内、鼻腔、眼内、皮肤等多种给药方式,具有广泛的应用前景。但是各种凝胶材料都存在不同缺点,比如天然生物材料具有可塑性差、机械强度不足、容易被病原微生物污染、难以大量生产的缺点,人工合成材料往往亲水性还不够,而且温敏型凝胶在体内的代谢途径对组织器官的影响也尚在研究中。 ORCID: 0000-0002-9070-7602(陈泳佳) 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

抑郁—躁狂阻击战,三大原则记心中

正双相障碍(bipolar disorder,BD)是一种周期性发作的慢性疾病,其特征为反复发作的躁狂、抑郁或混合发作,大多数患者首次起病表现为抑郁发作,部分患者在抗抑郁治疗后会出现轻躁狂或躁狂表现。一旦确诊双相障碍,患者必须尽快接受相应的药物治疗。目前,美国、加拿大、英国及我国的双相障碍防治指南都将药物治疗作为双相障碍的一线疗法。     

生物降解微球制剂的体内外相关性研究进展

可生物降解注射用微球是近年来发展较快的一种新剂型,它是指利用天然或合成的高分子材料,将固体或液体药物包嵌成直径为1～250μm的微小球体。该制剂技术将蛋白和多肽等类药物制备成以微球为载体的长效缓控释制剂。     

奥硝唑不同剂型抗阴道毛滴虫作用的比较研究

目的研究奥硝唑原料药、凝胶剂和栓剂在体内外抗阴道毛滴虫的作用。方法体内实验：在小鼠阴道内连续多日注入不同浓度奥硝唑、奥硝唑凝胶或奥硝唑栓剂和虫体,停药1 d后取阴道灌洗液涂片观察有无活动的阴道毛滴虫。体外实验：将阴道毛滴虫培养后分别接种到在含不同浓度奥硝唑、奥硝唑凝胶和奥硝唑栓剂的细胞培养板孔中,于不同时间在倒置显微镜下观察虫体形态变化,计数死虫百分率。结果体内试验中连续5 d注入药物和虫体的奥硝唑原料药组、奥硝唑凝胶剂组、奥硝唑栓剂组镜检阳性率均为0（0/20）,而无药对照组阳性率为100%（20/20）,差异有统计学意义（P〈0.01）。体外实验中药物作用滴虫24 h后,各种药物的最低有效抑虫浓度（虫体100%死亡）依次为：奥硝唑凝胶0.0025 mg/ml,奥硝唑原料0.0049 mg/ml,奥硝唑栓剂0.0195 mg/ml。结论奥硝唑凝胶剂具有良好的体内外抗阴道滴虫作用,其作用优于奥硝唑栓剂。     

紫杉醇PCL—PEG—PCL温敏性缓释凝胶的制备及性能研究

目的利用聚己内酯-聚乙二醇-聚己内酯（PCL1250-PEG1500-PCL1250）两亲性聚合物温敏凝胶作为载体材料,构建疏水性抗肿瘤药物紫杉醇的载药体系。方法以辛酸亚锡为催化剂、聚乙二醇为引发剂,引发己内酯单体开环聚合,合成PCL1250-PEG1500-PCL1250三嵌段共聚物。通过核磁共振氢谱及凝胶渗透色谱对其组成、结构及分子量进行表征;制备不同凝胶浓度及初始载药量的载药温敏凝胶,并对其相转变性能、体外药物释放行为以及体内的生物降解性能进行考察。结果核磁共振及凝胶渗透色谱测定结果表明：合成的共聚物组成与初始投料比一致,符合设计的PCL1250-PEG1500-PCL1250嵌段聚合物结构;该凝胶在15％～30％浓度区间内,具备温敏性溶胶-凝胶相转变能力;该温敏凝胶对紫杉醇具有可控的药物缓释能力,通过改变凝胶浓度及初始载药量可凋节药物释放速率和维持释放的时间。小鼠背部皮下注射PCL1250-PEG1500-PCL1250溶胶后在体内迅速原位凝胶化,凝胶随植入时间逐渐降解至45d时基本降解完全。结论PCL1250-PEG1500-PCL1250温敏凝胶作为紫杉醇载药体系具有良好的药物控释能力和体内生物降解性能。     

紫杉醇PCL-PEG-PCL温敏性缓释凝胶的制备及性能研究

目的 利用聚己内酯-聚乙二醇-聚己内酯(PCL1250-PEG1500-PCL1250)两亲性聚合物温敏凝胶作为载体材料,构建疏水性抗肿瘤药物紫杉醇的载药体系.方法 以辛酸亚锡为催化剂、聚乙二醇为引发剂,引发己内酯单体开环聚合,合成PCL1250-PEG1500-PCL1250三嵌段共聚物.通过核磁共振氢谱及凝胶渗透色谱对其组成、结构及分子量进行表征:制备不同凝胶浓度及初始载药量的载药温敏凝胶,并对其相转变性能、体外药物释放行为以及体内的生物降解性能进行考察.结果 核磁共振及凝胶渗透色谱测定结果表明:合成的共聚物组成与初始投料比一致,符合设计的PCL1250-PEG1500-PCL1250嵌段聚合物结构;该凝胶在15%～30%浓度区间内,具备温敏性溶胶-凝胶相转变能力;该温敏凝胶对紫杉醇具有可控的药物缓释能力,通过改变凝胶浓度及初始载药量可调节药物释放速率和维持释放的时间.小鼠背部皮下注射PCL1250-PEG1500-PCL1250溶胶后在体内迅速原位凝胶化,凝胶随植入时间逐渐降解至45 d时基本降解完全.结论 PCL1250-PEG1500-PCL1250温敏凝胶作为紫杉醇载药体系具有良好的药物控释能力和体内生物降解性能.     

水性组织透明化技术的研究进展与应用

由于生物样本的不透明性,以及组织深入成像的清晰度和深度不佳,因此大型、厚组织3D成像技术的发展与创新成为近年来的研究热点.组织透明化机技术是通过各种物理或化学的方式将组织变透明,并结合荧光显微镜来实现组织或器官三维成像的新技术,因其良好的荧光保存及透明效果,在软组织领域,尤其是神经领域得到了越来越广泛的应用.近年来,各种新型的组织透明化技术不断被报道出来,本文就被动浸润法水性透明化技术、水化法水性透明化技术、水凝胶嵌入法水性透明化技术的研究进展及应用做一综述.     

pH敏感含糖三元共聚水凝胶Poly(AM-CO-IA-VBG)的药物释放性能研究

用4-乙烯基苄基胺与葡萄糖内酯反应合成了4-乙烯苄基葡萄糖酰胺单体(VBG)。以亚甲基双丙烯酰胺(BisA)为交联剂,用过硫酸钾(KPS)引发丙烯酰胺(AM)、衣康酸(IA)及4-乙烯苄基葡萄糖酰胺使之共聚,得到pH敏感含糖结构的三元共聚水凝胶。用核磁共振及红外光谱对单体和水凝胶的结构进行了表征,研究了不同水凝胶中药物的释放性能,以及pH值及盐的浓度对水凝胶中药物释放的影响。结果表明:水凝胶中药物在低pH值时或盐中药物释放显著下降,表明水凝胶对酸或盐有强烈的响应性。     

γ射线辐照交联PVA水凝胶关节软骨修复材料 的结构与性能研究

目的 研究制备工艺对γ射线辐照交联PVA水凝胶关节软骨修复材料的结构与摩擦学性能的影响,为其在关节软骨损伤修复提供理论基础。方法 采用冷冻解冻和辐照交联相结合的方法制备聚乙烯醇(PVA)水凝胶,研究其微观形貌、含水量及与自然软骨配副的摩擦学性能。结果 (1)微观结构的观察表明,制备的PVA水凝胶具有三维多孔网络结构,辐照交联使得网络结构更加致密和完善;(2) 水凝胶的含水量随着辐照剂量和PVA浓度的增加而减小;(3) 在往复式销-盘摩擦磨损试验机上研究本水凝胶材料与自然关节软骨配副时的摩擦学性能,结果表明,摩擦的起始阶段,双相润滑机制其主导作用,载荷主要由水凝胶中的液体相所承担,摩擦系数较小,随着载荷作用时间的延长,固体相所承受载荷的比例相对增高,摩擦系数渐渐增大且趋于稳定,润滑机制转为边界润滑。摩擦系数随着辐照剂量和PVA浓度的增加而减小。     

Tannic Acid Physically Cross‐Linked Responsive Hydrogel

Tannic acid (TA) is a polyphenol‐rich compound found in many natural plants. There are large numbers of phenolic hydroxyls at the terminal of the TA molecule, being capable of forming hydrogen bonds with hydrogen‐bonding donating polymers such as polyvinylpyrrolidone (PVP) and then engineering a hydrogel network. The reversible switch between phenolic hydroxyls and quinones tuned by pH affords the dynamic nature of the resultant hydrogen bonds. The gels exhibit excellent shear‐thinning and self‐recovery properties. Moreover, the polyphenols can form coordinates with Fe(III) that link different TAs to form a hydrogel network. Hence, adding Fe(III) solution to the TA‐PVP sol can form additional interactions inside the TA‐PVP gel. The easy preparation of the dual‐responsive gels with nontoxic raw materials may allow for its application in the biomedical field.     

Swelling behavior of polyelectrolyte gels in the presence of salts

The swelling behavior of weakly crosslinked polyelectrolyte gels based on sodium methacrylate (PMA) and diallyldimethylammonium chloride (DADMAC) in aqueous medium was studied in the presence of different types of salts (NaCl, arginine hydrochloride, cetylpyridinium chloride (CPC), sodium dodecyl sulfate (SDS), and sodium dodecylbenzenesulfonate (SDBS)). It is shown that, starting from some characteristic concentration of a salt, a further increase of the salt concentration results in the shrinking of the gels. This characteristic concentration is defined by the gel parameters (polymer concentration in the gel that is a function of the monomer concentration at the conditions of hydrogel synthesis) and does not depend on the kind of salt used, except for the system polyelectrolyte gel/oppositely charged surfactant (PMA-CPC and DADMAC-SDS or SDBS). It is shown that the initial rate of gel shrinking for all studied systems, including the system gel/oppositely charged surfactant, is determined by the salt concentration and the gel parameters. For the systems PMA-CPC and DADMAC-SDS the gel collapse is a two-step process.     

The influence of physical structure and charge on neurite extension in a 3D hydrogel scaffold

Understanding neural cell differentiation and neurite extension in three-dimensional scaffolds is critical for neural tissue engineering. This study explores the structure-function relationship between a 3D hydrogel scaffold and neural cell process extension and examines the role of ambient charge on neurite extension in 3D scaffolds. A range of agarose hydrogel concentrations was used to generate varied gel physical structures and the corresponding neurite extension was examined. Agarose gel concentration and the corresponding pore radius are important physical properties that influence neural cell function. The average pore radii of the gels were determined while the gel was in the hydrated state and in two different dehydrated states. As the gel concentration was increased, the average pore radius decreased exponentially. Similarly, the length of neurites extended by E9 chick DRGs cultured in agarose gels depends on gel concentration. The polycationic polysaccharide chitosan and the polyanionic polysaccharide alginate were used to incorporate charge into the 3D hydrogel scaffold, and neural cell response to charge was studied. Chitosan and alginate were covalently bound to the agarose hydrogel backbone using the bi-functional coupling agent 1,1'carbonyldiimldazole. DRGs cultured in chitosan-coupled agarose gel exhibited a significant increase in neurite length compared to the unmodified agarose control. Conversely, the alginate-coupled agarose gels significantly inhibited neurite extension. This study demonstrates a strong, correlation between the ability of sensory ganglia to extend neurites in 3D gels and the hydrogel pore radius. In addition, our results demonstrate that charged biopolymers influence neurite extension in a polarity dependent manner.     

Synthesis,Characterization and Properties of a Physically and Chemically Gelling Polymer System Using Poly(NIPAAm-co-HEMA-acrylate) and Poly(NIPAAm-co-cysteamine)

The aim of this work was to develop a simultaneous physically and chemically gelling system using NIPAAm co-polymers. The in situ polymer gel was obtained by synthesizing poly(NIPAAm-co-HEMAacrylate) and poly(NIPAAm-co-cysteamine) through free radical polymerization and further nucleophilic substitution. The purpose of the dual gelation is that physical gelation would take place at higher temperatures as the NIPAAm chains associate, while chemical gelation would occur through a Michael-type addition reaction, resulting in a cross-link forming through a nucleophilic attack of the thiolate on the acrylate. The structure of each co-polymer was then verified using ¹H-NMR and FT-IR spectroscopy. The corresponding lower critical solution temperature and phase transition behavior of each co-polymer was analyzed through cloud point and DSC, while mechanical properties were investigated through rheology. Swelling behavior was also monitored at different temperatures. The resulting polymer system demonstrated properties compatible with physiological conditions, forming a gel at pH 7.4 and at temperatures near body temperature. The hydrogel also showed reduced viscoelastic flow at low frequency stress, and increased strength than purely physical or chemical gels. Swelling behavior was determined to be temperature-dependent; however, no difference was observed in swelling percent beyond 48 h. Having the ability to alter these co-polymers through various synthesis parameters and techniques, this hydrogel can potentially be used as an injectable, waterborne gelling material for biomedical applications such as endovascular embolization.     

Visible light cured thiol-vinyl hydrogels with tunable degradation for 3D cell culture

We report here a synthetically simple yet highly tunable and diverse visible light mediated thiol-vinyl gelation system for fabricating cell-instructive hydrogels. Gelation was achieved via a mixed-mode step-and-chain-growth photopolymerization using functionalized 4-arm poly(ethylene glycol) as backbone macromer, eosin-Y as photosensitizer, and di-thiol containing molecule as dual purpose co-initiator/cross-linker. N-vinylpyrrolidone (NVP) was used to accelerate gelation kinetics and to adjust the stiffness of the hydrogels. Visible light (wavelength: 400–700 nm) was used to initiate rapid gelation (gel points: ∼20 s) that reached completion within a few minutes. The major differences between current thiol-vinyl gelation and prior visible light mediated photopolymerization are that: (1) the co-initiator triethanolamine (TEA) used in the previous systems was replaced with multifunctional thiols and (2) mixed-mode polymerized gels contain less network heterogeneity. The gelation kinetics and gel properties at the same PEG macromer concentration could be tuned by changing the identity of vinyl groups and di-thiol cross-linkers, as well as concentration of cross-linker and NVP. Specifically, acrylate-modified PEG afforded the fastest gelation rate, followed by acrylamide and methacrylate-functionalized PEG. Increasing NVP concentration also accelerated gelation and led to a higher network cross-linking density. Further, increasing di-thiol peptide concentration in the gel formulation increased hydrogel swelling and decreased gel stiffness. Due to the formation of thiol-ether-ester bonds following thiol-acrylate reaction, the gels degraded hydrolytically following a pseudo first order degradation kinetics. Degradation rate was controlled by adjusting thiol or NVP content in the polymer precursor solution. The cytocompatibility and utility of this hydrogel system were evaluated using in situ encapsulation of human mesenchymal stem cells (hMSC). Encapsulated hMSCs remained alive (>90%) throughout the duration of the study and the cells were differentiated down osteogenic lineage with varying degrees by controlling the rate and mode of gel degradation.     

Fibroblast Morphology on Dynamic Softening of Hydrogels

Despite cellular environments having dynamic characteristics, many laboratories utilized static polyacrylamide hydrogels to study the ECM–cell relationship. To attain a more in vivo like environment, we have developed a dynamic, DNA-crosslinked hydrogel (DNA gel). Through the controlled delivery of DNA, we can temporally decrease or increase gel stiffness while expanding or contracting the gel, respectively. These dual mechanical changes make DNA gels a cell–ECM model for studying dynamic mechano-regulated processes, such as wound healing. Here, we characterized DNA gels on a mechanical and cellular level. In contrast to our previous publication, in which we examined the increasing stiffness effects on fibroblast morphology, we examined the effects of decreased matrix stiffness on fibroblast morphology. In addition, we quantified the bulk and/or local stress and strain properties of dynamic gels. Gels generated about 0.5 Pa stress and about 6–11% strain upon softening to generate larger and more circular fibroblasts. These results complemented our previous study, where dynamic gels contracted upon stiffening to generate smaller and longer fibroblasts. In conclusion, we developed a biomaterial that increases and decreases in stiffness while contracting and expanding, respectively. We found that the dynamic deformation directionality of the matrix determined the fibroblast morphology and possibly influences function.     

Long-term stable fibrin gels for cartilage engineering

It is essential that hydrogel scaffold systems maintain long-term shape stability and mechanical integrity for applications in cartilage tissue engineering. Within this study, we aimed at the improvement of a commercially available fibrin gel in order to develop a long-term stable fibrin gel and, subsequently, investigated the suitability of the optimized gel for in vitro cartilage engineering. Only fibrin gels with a final fibrinogen concentration of 25mg/ml or higher, a Ca(2+) concentration of 20mm and a pH between 6.8 and 9 were transparent and stable for three weeks, the duration of the experiment. In contrast, when preparing fibrin gels with concentrations out of these ranges, turbid gels were obtained that shrank and completely dissolved within a few weeks. In rheological characterization experiments, the optimized gels showed a broad linear viscoelastic region and withstood mechanical loadings of up to 10,000 Pa. Bovine chondrocytes suspended in the optimized fibrin gels proliferated well and produced the extracellular matrix (ECM) components glycosaminoglycans and collagen type II. When initially seeding 3 million cells or more per construct (5mm diameter, 2mm thick), after 5 weeks of culture, a coherent cartilaginous ECM was obtained that was homogenously distributed throughout the whole construct. The developed fibrin gels are suggested also for other tissue engineering applications in which long-term stable hydrogels appear desirable.     

Biomechanical properties of high-toughness double network hydrogels

This study evaluated the wear property of four novel double-network (DN) hydrogels, which was composed of two kinds of hydrophilic polymers, using pin-on-flat wear testing. The gels involve PAMPS-PAAm gel which consists of poly(2-acrylamide-2-metyl-propane sulfonic acid) and polyacrylamide, PAMPS-PDAAAm gel which consists of poly(2-acrylamide-2-metyl-propane sulfonic acid) and poly(N,N'-dimetyl acrylamide), Cellulose/PDMAAm gel which consists of bacterial Cellulose and poly dimetyl-acrylamide, and Cellulose-Gelatin gel which consists of bacterial Cellulose and Gelatin. Ultra-high molecular weight polyethylene (UHMWPE) was used as a control of a clinically available material. Using a reciprocating apparatus, 10(6) cycles of friction between a flat specimen and ceramic pin were repeated in water under a contact pressure of 0.1 MPa. To determine the depth and the roughness of the concave lesion created by wear, a confocal laser microscope was used. As a result, the maximum wear depth of the PAMPS-PDMAAm gel (3.20 microm) was minimal in the five materials, while there was no significant difference compared to UHMWPE. There were significant differences between UHMWPE and one of the other three gels. The PAMPS-PAAm gel (9.50 microm), the Cellulose-PDMAAm gel (7.80 microm), and the Cellulose-Gelatin gel (1302.40 microm). This study demonstrated that the PAMPS-PDMAAm DN gel has an amazing wear property as a hydrogel that is comparable to the UHMWPE. In addition, the PAMPS-PAAm and Cellulose-PDMAAm DN gels are also resistant to wear to greater degrees than conventionally reported hydrogels. On the other hand, this study showed that the Cellulose-Gelatin DN gel was not resistant to wear.     

Supramolecular hydrogels based on self-assembly between PEO-PPO-PEO triblock copolymers and alpha-cyclodextrin

This article reports a detailed study on the hydrogel formation of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymers with alpha-cyclodextrin (alpha-CD) in aqueous solutions. The gelation kinetics and the gel rheological properties were studied using viscometry. The sol-gel phase transitions were studied using phase diagrams, while the gelation mechanism was studied using differential scanning calorimetric analysis. It was concluded that the gelation was induced by the complex formation between the PEO segments of the PEO-PPO-PEO triblock copolymer and alpha-CD, and the further self-assembly of the partially formed inclusion complexes. The addition of alpha-CD largely reduced the concentration of the copolymer needed for gel formation. The gels were thixotropic and reversible, and potentially suitable for use as an injectable drug-delivery system.     

Apatite formation on/in hydrogel matrices using an alternate soaking process: II. Effect of swelling ratios of poly(vinyl alcohol) hydrogel matrices on apatite formation

In our previous study, we reported a novel method of apatite formation on/in a three-dimensional hydrogel matrix. Using this method, bone-like apatite could be formed on/in the hydrogel matrix under normal conditions in vitro. A poly(vinyl alcohol) (PVA) gel was used as a model matrix. The method consists of two steps: first, water is transformed in a PVA gel with a CaCl2/Tris-HCl aqueous solution (pH 7.4) and second, the gel is soaked in a Na2HPO4 aqueous solution. In the present study, we report a detailed study of the effects of the swelling ratios of PVA gels on apatite formation. Cross-sectional observations and gravimetric measurements of PVA gels with various swelling ratios were done. The amount of apatite formed on/in PVA gels increased almost linearly with an increase in the reaction cycles. The rates of apatite formation on/in PVA gels largely depended on the swelling ratios, which were approximately 0.48, 0.61, 1.28, and 1.55 mg per cycle for swelling ratios of 4.1, 10.4, 16.8, and 30.1, respectively. The apatite content in PVA-apatite composites that was obtained by this method also increased with an increase of the reaction cycles. After six reaction cycles, a PVA gel with a high swelling ratio contains approximately 70 wt% of formed apatite in the composite. On the other hand, a gel with a low swelling ratio contains about 15 wt% of formed apatite in the composite. Cross-sectional views of the PVA gels after each cycle showed that apatite crystals were formed, not only on the surface of the gel but also within it after fifteen reaction cycles. The hydrogel-apatite composites that were obtained using an alternative soaking process will be useful as not only bone substitute materials but also as soft tissue adhesive materials.