海藻酸钙止血敷料与临床常用3种止血敷料体外细胞毒性的比较

背景：止血敷料是作用于创伤表面与人体组织直接接触,其生物相容性是评价敷料优劣的重要指标之一,以海藻酸钙为原料的制备的止血敷料有着廉价、相容性好等优点已成为研究的热点。目的：观察海藻酸钙止血敷料的细胞毒性,并与明胶止血海绵、纳吸棉、普通纱布等材料作对比。方法：①浸提液法：以DMEM高糖培养液作为浸提介质,分别制备海藻酸钙止血敷料、明胶止血海绵、纳吸棉、普通纱布浸提液,并设置100%,75%,50%,25%,10% 5个浓度梯度;采用上述材料浸提液培养L-929小鼠成纤维细胞24 h,以含体积分数10%DMEM高糖培养液为空白对照,以含5%二甲基亚砜DMEM高糖培养液为阳性对照组,观察细胞增殖及形态变化。②直接接触法：将L-929小鼠成纤维细胞分别接种于海藻酸钙止血敷料、明胶止血海绵、纳吸棉、普通纱布上培养24 h,观察细胞形态变化。结果与结论：①浸提液法：不同浓度梯度海藻纤维止血敷料、纱布、纳吸棉浸提液的细胞毒性均为1级,符合GB/T16886/ISO10993 医疗器械生物学评价标准;100%,75%明胶止血海绵浸提液的细胞毒性为3级,严重抑制细胞增殖。②直接接触法：纱布与海藻纤维止血敷料的细胞毒性1级,纳吸棉为2级,明胶止血海绵的细胞毒性为3级。表明海藻酸钙止血敷料无细胞毒性。 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     

生物止血敷料及纱布在外科伤口中的应用评价

背景:近年来,随着生物医用高分子材料如纤维素、甲壳素等天然高分子材料以及聚乙烯醇、胶原等合成高分子材料的研发,多种外科止血生物材料应用于临床。目的:评价不同生物止血敷料及纱布的材料学性能及应用于外科伤口的生物相容性,寻找符合不同伤口创面需要的止血材料。方法:以"生物材料,止血敷料,纱布,胶原/壳聚糖,生物相容性"为中文关键词;以:"biomaterial;hemostatic material;bioresorbable material;hemostasis effect;hemostatic mechanism"为英文关键词,采用计算机检索2000-01/2010-06相关文章。纳入与生物敷料、纱布在伤口止血方面应用及这些材料与人体相容性的文章;排除重复研究或Meta分析类文章。以33篇文献为主重点进行讨论不同生物止血材料性能及生物相容性。结果与结论:近几年国内外生物医用可吸收止血材料主要包括纤维蛋白胶、壳聚糖、明胶海绵、氰基丙烯酸酯类组织胶、氧化纤维素和氧化再生纤维素等。各种止血性伤口急救材料都有各自的特点,但在临床应用的选择上,应考虑多方面因素,包括手术部位、出血部位、伤口形态大小、不同渗/出血情况的填塞要求、不同止血材料的自身性能及与机体的相容性等。但因目前尚无完全符合理想标准的材料,因此开发新的快速止血和与宿主相容性良好的止血材料及复合材料势在必行。     

生物止血材料在妇产科手术中的应用

背景：良好的生物敷料或纱布可直接促进凝血过程,不仅可用于广泛渗血创面,且在一些常用的妇产科手术中能有效降低渗血率。 目的：评价不同生物止血敷料及纱布的材料学性能及应用于妇产科切口的生物相容性,寻找符合不同切口创面需要的止血材料。 方法：采用电子检索的方式,在万方数据库(http://www.wanfangdata.com.cn/)中检索1999-01/2011-04有关妇产科生物止血材料应用的研究文章,关键词为“妇产科,生物材料,止血敷料,纱布,胶原/壳聚糖”,排除重复研究、普通综述或Meta分析类文章,筛选纳入30篇文献进行评价。 结果与结论：近几年国内外生物医用可吸收止血材料主要包括纤维蛋白胶、壳聚糖、明胶海绵、氰基丙烯酸酯类组织胶、氧化纤维素和氧化再生纤维素等。各种止血性伤口急救材料都有各自的特点,但在妇产科应用的选择上,应考虑多方面因素,包括手术部位、出血部位、切口形态大小、不同渗/出血情况的填塞要求、不同止血材料的自身性能及与机体的相容性等。但因目前尚无完全符合理想标准的材料,因此开发新的快速止血和与宿主相容性良好的止血材料及复合材料势在必行。     

胶原/透明质酸膜与明胶海绵支架材料力学及组织相容性的比较

背景：课题组前期实验证明胶原/透明质酸膜具有良好的力学性能和组织相容性。 目的：观察复合材料胶原/透明质酸膜及明胶海绵的生物学性能。 方法：应用材料复合交联的实验方法构建胶原/透明质酸膜并测定胶原/透明质酸膜、明胶海绵支架的力学性能。将支架材料种植于兔皮下,按照2,4,6,8,12周不同时间点评价材料在体内的降解情况和组织相容性。 结果与结论：①成功制备了胶原/透明质酸膜。②胶原/透明质酸膜具有较好的韧性和抗张强度,明胶海绵的力学性能不够理想。③两种材料在体内的降解均符合生物材料的组织反应过程,胶原/透明质酸膜在体内12周可完全降解,明胶海绵约6周完全降解。④胶原/透明质酸膜与平滑肌细胞的黏附率高,细胞的增殖和代谢状况较好,而明胶海绵的细胞黏黏附和增殖率相对较低。说明胶原/透明质酸膜具有较好的生物学性能。     

地塞米松明胶海绵预防硬脊膜外粘连

背景：临床上在腰椎间盘摘除中将地塞米松明胶海绵复合物放置在神经根和硬脊膜周围取得了良好的效果。目的：通过动物实验了解地塞米松明胶海绵复合物预防硬脊膜外粘连的效果。方法：将40只新西兰白兔随机均分为4组,均切除L₄、L₇椎板,造成1.0 cm×0.5 cm的硬脊膜裸露区后,其中3组分别在硬脊膜与神经根表面覆盖地塞米松明胶海绵、注射地塞米松及覆盖明胶海绵,以不用任何间置物覆盖的为空白组。术后2,4,6,8,12周完整取下整个手术节段椎体及其附件和椎旁肌,大体及组织学观察神经根及硬脊膜粘连程度。结果与结论：术后12周,地塞米松明胶海绵组大体见椎板缺损处有新生骨形成,硬脊膜周围有黄白色膜性组织,可分离,组织学见脂肪细胞结构完整,与硬脊膜之间分界明显,无瘢痕细胞形成,无粘连,软骨细胞及骨小梁增生;地塞米松组、明胶海绵组、空白组大体见硬脊膜外围有大量瘢痕组织,与硬脊膜粘连严重,无法钝性分离,组织学见芽组织胶原化,硬脊膜增厚,粘连严重。表明地塞米松明胶海绵复合物可预防硬脊膜外粘连。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;组织工程全文链接：     

胶原/壳聚糖止血敷料在外科伤口中的应用

背景：壳聚糖与胶原联合可更有效地止血。 目的：评价胶原/壳聚糖止血敷料的材料学性能及应用于外科伤口的生物相容性。 方法：以“生物材料,止血敷料,纱布,胶原/壳聚糖,生物相容性”为中文关键词,以“biomaterial;hemostatic material;bioresorbable material;hemostasis effect;hemostatic mechanism”为英文关键词,采用计算机检索2000-01/2010-06与生物敷料、胶原/壳聚糖止血材料在伤口或创面止血过程中应用相关的文献。 结果与结论：壳聚糖独特的生物学特性,具有广谱抑菌、促进上皮细胞生长及止血,促进创面愈合的作用,在体内具有良好的生物降解性与组织相容性,可用于指端损伤和肉芽创面的治疗,如制成伤口敷料、可吸收缝线、止血材料、防粘连剂、药物缓释及组织工程支架,用于平战时伤口的处理。     

胶原蛋白海绵对肝脏创伤止血的效果北大核心

背景:艾瑞金胶原蛋白海绵理化性能稳定,并已通过国家食品药品监督管理局的理化性能和生物相容性评价检测。目的:观察艾瑞金胶原蛋白海绵的止血效果。方法:取21只SD大鼠,建立肝脏出血创面,随机分3组干预:在实验组(n=7)肝脏创口内部植入艾瑞金胶原蛋白海绵,同时在肝脏切口表面外敷艾瑞金胶原蛋白海绵;在阳性对照组(n=7)肝脏创口内部植入医用胶原蛋白海绵,同时在肝脏切口表面外敷医用金胶原蛋白海绵;在空白对照组(n=7)肝脏切口表面外敷医用纱布,记录出血量及止血时间,干预后7,14,28 d进行肝脏创面组织学观察。结果与结论:①出血量及止血时间:3组出血量比较无差异;实验组、阳性对照组止血时间与空白对照组比较差异无显著性意义,实验组止血时间短于阳性对照组(P≤0.05);②肝脏创面组织学观察:实验组干预后7 d胶原材料被纤维结缔组织完全包裹,炎性细胞浸润以中性粒细胞为主,胶原材料开始降解,周边结缔组织内有新生毛细血管;干预后14 d,包裹胶原材料的纤维结缔组织明显增厚,中性粒细胞减少,巨噬细胞增多;干预后28 d,胶原材料完全降解,大部肝组织恢复正常,部分肝组织旁的炎性结缔组织中可看到巨噬细胞、单核细胞、成纤维细胞和毛细血管。阳性对照组情况类似于实验组。空白对照组干预后14 d创伤处结缔组织明显,肝窦含有红细胞,偶见肝组织内出血,空泡变性;干预后28 d,创口处具有较厚结缔组织,肝窦含有红细胞,被复肝星状细胞;③结果表明:艾瑞金胶原蛋白海绵对肝脏创伤止血效果明显,组织相容性好。     

可吸收止血材料的研究现状及临床应用

简要综述了近年国内外主要的可吸收止血材料包括可吸收纤维蛋白胶、氧化纤维素、氧化再生纤维素、壳聚糖、α-氰基丙烯酸酯类组织胶、可吸收性明胶海绵和明胶纤维网、微纤维胶原和胶原纤维网、海藻酸钙纤维的组成、止血机理、止血性能、研究现状及临床应用,展望了可吸收止血材料未来的发展趋势.对医生了解医用可吸收止血材料的止血特性、掌握正确的使用方法、充分发挥其止血效果,提供了一定的参考价值,同时,对医用材料工作者进一步研究止血材料提供了参考.     

壳聚糖-胶原角膜修复材料的制备及生物相容性

背景：将胶原和壳聚糖按一定比例制成复合膜后,能够降低壳聚糖的正电荷,改善壳聚糖的吸附力,促进细胞的黏附生长、迁移和增殖,增强壳聚糖的生物学性能,成为十分优良的生物材料。 目的：制备壳聚糖-胶原复合膜,观察其与角膜基质层的组织相容性。 方法：制作壳聚糖-胶原复合膜材料。将16只新西兰兔随机分为两组,实验组于右眼角膜基质袋内植入壳聚糖-胶原复合膜,对照组右眼角膜基质袋内植入壳聚糖膜。移植后进行裂隙灯显微镜、前节-光学相干断层成像及组织学观察。 结果与结论：①裂隙灯显微镜：移植后第8周,实验组膜片中央出现降解浸润,皱褶屈曲不明显;对照组膜片全部浸润,皱褶屈曲明显。②前节-光学相干断层成像：移植后第6周,实验组的复合膜边界模糊,密度与正常角膜组织很接近,角膜形态恢复正常。③组织学观察：移植后第8周,实验组膜片表层少量降解,降解材料与角膜基质融合,膜片周围角膜基质有少量炎性细胞浸润;对照组膜片表层降解程度大于实验组,降解物质与角膜基质交织融合,膜片周围角膜基质有较多炎性细胞浸润。表明壳聚糖-胶原复合膜具有可降解性和良好的组织相容性。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     

温敏性壳聚糖水凝胶对大鼠成骨细胞的毒性

背景：温敏性壳聚糖与多种细胞相容性良好,是组织工程中不可多得的优良载体,但其对成骨细胞毒性研究相对缺乏。 目的：验证温敏性壳聚糖水凝胶对成骨细胞的毒性。 方法：成骨细胞在温敏性壳聚糖水凝胶中进行培养,显微镜下观察细胞形态及扩增情况,同时,SD大鼠成骨细胞在不同浓度的温敏性壳聚糖水凝胶浸提液中体外培养24,48,72,96 h,MTT法测定细胞相对增殖率,判断细胞毒性的级别。 结果与结论：SD大鼠成骨细胞在温敏性壳聚糖水凝胶中培养24 h内镜下观察呈圆形,48 h后开始伸出触角并扩增;温敏性壳聚糖水凝胶浸提液中培养的各组细胞在不同时间点相对增殖率在92%~112%之间,各浓度的温敏性壳聚糖水凝胶材料浸提液的细胞毒性均为0级或1级,完全符合生物材料的安全评价标准。     

A novel mucoadhesive polymer prepared by template polymerization of acrylic acid in the presence of chitosan

A novel mucoadhesive polymer was prepared by template polymerization of acrylic acid in the presence of chitosan for transmucosal drug delivery system (TMD). FT-IR results indicated that polymer complex was formed between poly(acrylic acid) (PAA) and chitosan through hydrogen bonding. Glass transition temperature (Tg) of chitosan and PAA in the PAA/chitosan polymer complexes was inner-shifted compared with Tg of chitosan and PAA itself. This may be due to the increased miscibility of PAA with chitosan through the hydrogen bonding. The crystallinity of chitosan in the PAA/chitosan polymer complexes was decreased with polymer complex formation with PAA. The dissolution rate of the PAA/chitosan polymer complex was dependent on pH and ratio of PAA/chitosan. The mucoadhesive force of PAA/chitosan polymer complex was similar to a commericial product, Carbopol 971P NF.     

In vitro evaluation of a chitosan membrane cross-linked with genipin

The study was to evaluate the characteristics of a chitosan membrane cross-linked with a naturally-occurring cross-linking reagent, genipin. This newly-developed genipin-cross-linked chitosan membrane may be used as an implantable drug-delivery system. The chitosan membrane without cross-linking (fresh) and the glutaraldehyde-cross-linked chitosan membrane were used as controls. The characteristics of test chitosan membranes evaluated were their cross-linking degree, swelling ratio, mechanical properties, antimicrobial activity, cytotoxicity, and degradability. It was found that cross-linking of chitosan membrane using genipin increased its ultimate tensile strength but significantly reduced its strain-at-fracture and swelling ratio. There was no significant difference in antimicrobial activity between the genipin-cross-linked chitosan membrane and its fresh counterpart. Additionally, the results showed that the genipin-cross-linked chitosan membrane had a significantly less cytotoxicity and a slower degradation rate compared to the glutaraldehyde-cross-linked membrane. These results suggested that the genipin-cross-linked chitosan membrane may be a promising carrier for fabricating an implantable drug-delivery system. The drug-release characteristics of the genipin-cross-linked chitosan membrane are currently under investigation.     

基于壳聚糖的医用可吸收止血贴的研究与应用

几丁质是自然界中合成的产量仅次于纤维素的天然有机化合物,其经过脱乙酰作用生成的壳聚糖具有优良的生物及化学性质;此外通过改变聚合度、脱乙酰度或经过不同官能团的修饰,壳聚糖的理化性质可以发生变化,因此它在生物医药和保健领域的应用倍受重视.本文首先叙述了壳聚糖及其衍生物与止血相关的性质与功能,说明了壳聚糖可作为止血贴主要材料的巨大应用价值,然后阐述了壳聚糖及其止血贴产品的研究现状与生产手段,最后依据目前研究现状,对基于壳聚糖的可吸收止血贴产品的未来发展趋势进行了展望.     

The influence of molecular weight of chitosan on the physical and biological properties of collagen/chitosan scaffolds

Biopolymer blends between collagen and chitosan have the potential to produce cell scaffolds with biocompatible properties. However, the relationship between the molecular weight of chitosan and its effect on physical and biological properties of collagen/chitosan scaffolds has not been elucidated yet. Porous scaffolds were fabricated by freeze-drying the solution of collagen and chitosan, followed by cross-linking by dehydrothermal treatment. Various types of scaffolds were prepared using chitosan with various molecular weights and blending ratios. Fourier transform infrared spectroscopy proved that collagen and chitosan scaffolds at all blending ratios contained mainly electrostatic interactions at the molecular level. The compressive modulus decreased with increasing the concentration of chitosan. Equilibrium swelling ratios of approximately 6–8, determined in phosphate-buffered saline at physiological pH (7.4), were found in case of collagen-dominated scaffolds. The lysozyme biodegradation test demonstrated that the presence of chitosan, especially the high-molecular-weight species, could significantly prolong the biodegradation of collagen/chitosan scaffolds. In vitro culture of L929 mouse connective tissue fibroblast evidenced that low-molecular-weight chitosan was more effective to promote and accelerate cell proliferation, particularly for scaffolds containing 30 wt% chitosan. The results elucidated that the blends of collagen with low-molecular-weight chitosan have a high potential to be applied as new materials for skin-tissue engineering.     

Platelet derived growth factor releasing chitosan sponge for periodontal bone regeneration

With an aim of improving bone regeneration, chitosan sponge containing platelet-derived growth factor-BB (PDGF-BB) were developed. For fabrication of chitosan sponge, chitosan solution was freeze-dried, crosslinked and freeze-dried again. PDGF-BB was incorporated into the chitosan sponge by soaking chitosan sponge into the PDGF-BB solution. Release kinetics of PDGF-BB, cell attachment, proliferation capacity and bony regenerative potentials of PDGF-BB-loaded chitosan sponge were investigated. Prepared chitosan sponge retained porous structure with 100 microm pore diameter that was suitable for cellular migration and growth. Release rate of PDGF-BB could be controlled by varying initial loading content of PDGF-BB to obtain optimal therapeutic efficacy. PDGF-BB-loaded chitosan sponge induced significantly high cell attachment and proliferation level, which indicated good cellular adaptability. PDGF-BB-loaded chitosan sponge demonstrated marked increase in new bone formation and rapid calcification. Degradation of the chitosan sponge was proceeded at defect site and subsequently replaced with new bone. Histomorphometric analysis confirmed that PDGF-BB-loaded chitosan sponge significantly induced new bone formation. These results suggested that chitosan sponge and PDGF-BB-loaded chitosan sponge may be beneficial to enhance periodontal bone regeneration.     

In vitro evaluation of a chitosan membrane cross-linked with genipin.

The study was to evaluate the characteristics of a chitosan membrane cross-linked with a naturally-occurring cross-linking reagent, genipin. This newly-developed genipin-cross-linked chitosan membrane may be used as an implantable drug-delivery system. The chitosan membrane without cross-linking (fresh) and the glutaraldehyde-cross-linked chitosan membrane were used as controls. The characteristics of test chitosan membranes evaluated were their cross-linking degree, swelling ratio, mechanical properties. antimicrobial activity, cytotoxicity, and degradability. It was found that cross-linking of chitosan membrane using genipin increased its ultimate tensile strength but significantly reduced its strain-at-fracture and swelling ratio. There was no significant difference in antimicrobial activity between the genipin-cross-linked chitosan membrane and its fresh counterpart. Additionally, the results showed that the genipin-cross-linked chitosan membrane had a significantly less cytotoxicity and a slower degradation rate compared to the glutaraldehyde-cross-linked membrane. These results suggested that the genipin-cross-linked chitosan membrane may be a promising carrier for fabricating an implantable drug-delivery system. The drug-release characteristics of the genipin-cross-linked chitosan membrane are currently under investigation.     

Effect of chitosan molecular weight and deacetylation degree on hemostasis

Comparative studies have been carried out among solid-state chitosan soliquoid, chitosan acetic acid physiological saline solution, and carboxymethyl chitosan physiological saline solution to discover the hemostatic effect of molecular weight (M(w)) and deacetylation degree (DA) of chitosan. It was found that solid-state chitosan and chitosan acetic acid physiological saline solution performed different hemostatic mechanisms. When blood mixed with chitosan acetic acid physiological saline solution, the erythrocytes aggregated and were deformed. The DA, especially a low DA, in the chitosan acetic acid physiological saline solution, had a significant effect on the unusual aggregation and deformation of erythrocytes, compared with the effect of M(w) within a range between 10(5) and 10(6). However, this phenomenon could not be observed in solid-state chitosan soliquoid. Solid-state chitosan with a low DA absorbed more platelets and was more hemostatic. Carboxymethyl chitosan physiological saline solution had nothing to do with the aggregation and deformation of erythrocytes but caused local rouleau. The values of thrombin time (TT), prothrombin time (PT), activated partial thromboplastin time (APTT), and fibrinogen concentration (FIB) were measured after the blood was mixed with solid-state chitosan soliquoid, chitosan acetic acid physiological saline solution, and carboxymethyl chitosan physiological saline solution, separately. The results demonstrated that coagulation factors might not be activated by them.     

Quantum-dot-assisted fluorescence resonance energy transfer approach for intracellular trafficking of chitosan/DNA complex

Fluorescence resonance energy transfer (FRET) was employed to monitor the molecular dissociation of a chitosan/DNA complex with different molecular weights of chitosan. Chitosan with different molecular weights was complexed with plasmid DNA and the complex formation was monitored using dynamic light scattering and a gel retardation assay. As the chitosan molecular weight increased, a more condensed complex was prepared at various ratios of chitosan to DNA. Plasmid DNA and chitosan were separately labeled with quantum dots and Texas red, respectively, and the dissociation of the complex was subsequently monitored using confocal microscopy and fluorescence spectroscopy. As the chitosan molecular weight in the chitosan/DNA complex increased, the Texas red-labeled chitosan gradually lost FRET-induced fluorescence light when HEK293 cells incubated with chitosan/DNA complex were examined with confocal microscopy. This suggests that the dissociation of the chitosan/DNA complex was more significant in the high molecular weight chitosan/DNA complex. Fluorescence spectroscopy also monitored the molecular dissociation of the chitosan/DNA complex at pH 7.4 and pH 5.0 and confirmed that the dissociation occurred in acidic environments. This finding suggests that the high molecular weight chitosan/DNA complex could easily be dissociated in lysosomes compared to a low molecular weight complex. Furthermore, the high molecular weight chitosan/DNA complex showed superior transfection efficiency in relation to the low molecular weight complex. Therefore, it could be concluded that the dissociation of the chitosan/DNA complex is a critical event in obtaining the high transfection efficiency of the gene carrier/DNA complex.     

The influence of molecular weight of chitosan on the physical and biological properties of collagen/chitosan scaffolds

Biopolymer blends between collagen and chitosan have the potential to produce cell scaffolds with biocompatible properties. However, the relationship between the molecular weight of chitosan and its effect on physical and biological properties of collagen/chitosan scaffolds has not been elucidated yet. Porous scaffolds were fabricated by freeze-drying the solution of collagen and chitosan, followed by cross-linking by dehydrothermal treatment. Various types of scaffolds were prepared using chitosan with various molecular weights and blending ratios. Fourier transform infrared spectroscopy proved that collagen and chitosan scaffolds at all blending ratios contained mainly electrostatic interactions at the molecular level. The compressive modulus decreased with increasing the concentration of chitosan. Equilibrium swelling ratios of approximately 6-8, determined in phosphate-buffered saline at physiological pH (7.4), were found in case of collagen-dominated scaffolds. The lysozyme biodegradation test demonstrated that the presence of chitosan, especially the high-molecular-weight species, could significantly prolong the biodegradation of collagen/chitosan scaffolds. In vitro culture of L929 mouse connective tissue fibroblast evidenced that low-molecular-weight chitosan was more effective to promote and accelerate cell proliferation, particularly for scaffolds containing 30 wt% chitosan. The results elucidated that the blends of collagen with low-molecular-weight chitosan have a high potential to be applied as new materials for skin-tissue engineering.     

Photo-cross-linkable and thermo-responsive hydrogels containing chitosan and Pluronic for sustained release of human growth hormone (hGH)

A Pluronic/chitosan hydrogel was prepared by employing di-acrylated Pluronic and acrylated chitosan for thermo-responsive and photo-cross-linkable in situ gelation. Mixtures of diacrylated Pluronic and acrylated chitosan were transformed to physical gels at elevated temperatures and the gelation temperature of the hydrogels gradually increased by increasing chitosan content in the hydrogels from 0% to 15%. Photo-cross-linked Pluronic/chitosan hydrogels were prepared by UV irradiation of the physical gels above their gelation temperatures. Hydrogels with a long photo-cross-linking time showed low degradation rates and chitosan contents in the hydrogels also impeded the degradation rates of the hydrogels, which was caused by a high degree of inter-connected polymer networks between acrylated Pluronic and acrylated chitosan. Human growth hormone (hGH), mixed with the mixture of Pluronic and chitosan, was photo-cross-linked to prepare biodegradable hGH hydrogels. The hydrogels containing hGH showed sustained release profiles for those with long photo-cross-linking times and high chitosan contents in the hydrogel. The hydrogels with a long cross-linking time showed impeded release of the protein and high content of chitosan in the hydrogels also decreased burst release of hGH from the hydrogels while hGH was rapidly released out for the hydrogels with low content of chitosan.