钛及钛合金种植体表面处理的研究进展

钛的优良特性早已被公认为首选牙用种植材料,其表面氧化膜是形成骨结合的关建。为了进一步增加其耐腐蚀性和生物相容性,人们采取了多种方式进行表面处理,最终达到在植入体的不同部位产生不同的粗糙表面,以利于不同细胞在不同地方的附着,增加其生物活性。同时,达到避免各种污染物对纯钛种植体影响的目的。近年来钛种植体材料表面处理已经成为研究热点,本文就表面处理的方法进行综述。     

种植体稳定系数测定与种植体负重时机选择

目的:通过测量ITI和Osstem-SS种植系统的稳定系数(ISQ),评价这两种种植体的骨结合情况,为临床确定其上部结构修复时机提供依据。方法:93例牙列缺损患者共植入179颗种植体,根据患者种植区骨量情况分为两组,其中A组为种植区骨量良好,不需骨增量手术病例(62例);B组为种植区骨量不足,需进行骨增量手术病例(31例)。A组共植入125颗种植体,其中ITI种植系统64颗,OSSTEM-SS种植系统61颗;B组共植入54颗种植体,其中ITI种植系统28颗,OSSTEM-SS种植系统26颗。术后即刻及第4、6、8、12、16、24周分别测量各时期种植体稳定系数(ISQ),并同期进行临床和影像学检查。结果:A组中ITI种植系统术后8周ISQ值平均(74.17±1.85),进行负重;OSSTEM-SS种植系统术后12周ISQ值平均(72.00±2.59),进行负重。B组中ITI种植系统术后16周ISQ值平均(65.09±3.42),进行负重;OSSTEM-SS种植系统术后24周ISQ值平均(62.09±6.16),进行负重。负重后临床随访3-24个月所有病例均成功,咀嚼功能良好,患者满意。结论:种植体稳定系数(ISQ)能反应种植体骨结合情况,可以协助医生选择种植后合适的冠修复时机。     

三种不同表面活性剂对羟基磷灰石纳米颗粒的表面修饰的比较

目的:本研究旨在通过不同方法修饰羟基磷灰石纳米颗粒并检测其稳定性及分散性。方法:首先采用水合热合成法制备羟基磷灰石纳米颗粒,然后用透射电镜(TEM)和场发射扫描电镜(SEM)对其表面形态结构进行表征。我们首次用溴化十六烷三甲基铵(CTAB),PEG2000和人血清对羟基磷灰石纳米颗粒通过共价结合或表面吸附的方式进行表面嫁接,并利用透射电镜,傅里叶红外光谱(FT-IR)和X射线衍射(XRD)对新合成的这三种纳米羟基磷灰石复合物的形貌,结构和晶粒粒径进行表征。对这三种羟基磷灰石纳米颗粒悬浮液的时间沉降曲线进行分析。在分散性上通过检测这三种羟基磷灰石复合物悬浮液在不同pH值下的Zeta电位并绘制Zeta-pH曲线。结果:我们发现CTAB修饰的羟基磷灰石纳米颗悬浮液的悬浮稳定性最佳,其次是PEG2000,最后是人血清。在pH=7.0时,CTAB修饰的羟基磷灰石纳米颗粒的zeta电位值是25.68 m V,而PEG2000修饰的Zeta电位是4.32m V,人血清修饰的Zeta电位是-13.23m V。结论:CTAB表面修饰的羟基磷灰石纳米颗粒相对于其它两种表面活性剂复合物具有更好的分散性和悬浮稳定性,与DNA/RNA结合能力更强。本课题的结果给羟基磷灰石纳米颗粒载体的应用提供了一种新的选择,有望利用亲和力更高的基因载体实现基因治疗,具有广阔的应用前景。     

Chitosan in Surface Modification for Bone Tissue Engineering Applications

Traditional methods of bone defect repair include autografts, allografts, surgical reconstruction, and metal implants that have several disadvantages such as donor site morbidity, rejection, risk of disease transmission, and repetitive surgery. Biomaterial‐based bone reconstructions can, therefore, be an efficient alternative due to the inherent properties of the materials. Chitosan (CS), the deacetylated form of chitin, is a biopolymer having a wide array of applicability in regenerative tissue applications owing to its biocompatible, in vitro degradative and bioresorbable nature. Extensive studies are being carried out using CS to augment the properties of the already existing methods and to also improve the applicability of CS‐based biocomposites in bone tissue repair. In this review, the suitability of CS as a surface modifier has been discussed in detail for the already existing implants, surface modifications of CS‐based natural biocomposites for bone tissue regeneration, and the wide range of techniques that can introduce these modifications. CS, being a natural polymer, possesses advantageous properties including surface modifier that makes it a suitable candidate for bone regeneration, and further research to investigate its osteogenic potential in vivo along with the molecular and signaling mechanisms involved in bone regeneration can aid in expanding its applicability in clinical trials.     

下颌LOCATOR种植覆盖义齿咀嚼效率的比较

目的：种植支持的覆盖义齿是针对下颌骨后牙区没有足够骨量的病人的一种适当的治疗方案。LOCATOR是近年来一种新型改良的种植体附着系统。本研究在病人佩戴LOCATOR附着系统支持的下颌种植覆盖义齿后,通过比较不同种植体数量对咀嚼效率的影响,以期用最小的成本达到较好的临床效果。方法：19名下颌无牙颌患者中,10名植入2枚种植体,9名植入3枚种植体。三月后行LOCATOR附着系统支持的种植覆盖义齿修复,并计算咀嚼效率增加量。结果：通过SPSS20．0软件进行统计分析,采用95％可信区间,α=0．05,对两组覆盖义齿咀嚼效率的增加量进行t检验：P〉0．05,两组之间咀嚼效率的增加量无显著性差异。针对下颌LOCATOR种植覆盖义齿,植入两枚种植体和三枚种植体提升的咀嚼效率并无统计学差异。结论：针对LOCATOR系统支持的下颌种植覆盖义齿,两枚种植体既能有效地提高咀嚼效率。     

慢性牙周炎对牙种植修复的疗效影响

目的:分析慢性牙周对种植义齿修复疗效的影响。方法:选择2013年7月至2015年6月在宝鸡市中医医院接受牙种植修复治疗的慢性牙周炎患者52例(70枚)作为观察组及同期接受牙种植的牙周健康患者49例(69枚),作为对照组。观察分析两组患者种植修复1、3、6、12个月的边缘骨吸收量(MBL)、改良菌斑指数(m PLI)、改良龈沟出血指数(m SBI)、探测深度(PD)以及种植体龈沟液IL-1、IL-6水平的变化情况。结果:种植1年后,对照组的种植成功率为97.10%(67/69),观察组的种植成功率为91.42%(64/70),两组比较差异无统计学意义(P0.05)。种植1个月及3个月后,两组的m PLI、m SBI、PD以及MBL比较无明显差异(P0.05);种植6个月后,观察组的m SBI、PD以及MBL显著高于对照组(P0.05),m PLI仍无明显变化。此外,种植1个月、3个月时,对照组的IL-1β未检出;6个月后,观察组的IL-1β显著高于对照组(P0.05);种植3个月后,观察组的IL-6显著高于对照组(P0.05)。结论:慢性牙周炎可降低牙种植修复治疗的疗效,可能与种植体周围炎的发生有关。     

Preparation, characterization and antimicrobial activity of a bio-composite scaffold containing chitosan/nano-hydroxyapatite/nano-silver for bone tissue engineering

In this study, a bio-composite scaffold containing chitosan/nano-hydroxyapatite/nano-silver particles (CS/nHAp/nAg) was developed by freeze drying technique, followed by introduction of silver ions in controlled amount through reduction phenomenon by functional groups of chitosan. The scaffolds were characterized using SEM, FT-IR, XRD, swelling, and biodegradation studies. The testing of the prepared scaffolds with Gram-positive and Gram-negative bacterial strains showed antibacterial activity. The scaffold materials were also found to be non-toxic to rat osteoprogenitor cells and human osteosarcoma cell line. Thus, these results suggested that CS/nHAp/nAg bio-composite scaffolds have the potential in controlling implant associated bacterial infection during reconstructive surgery of bone.     

Ti2448合金种植体表面不同纳米管径生物活性膜对成骨细胞早期黏附的影响

观察Ti2448合金表面不同纳米管径生物活性膜对成骨细胞早期黏附的影响,筛选出能够抵抗细菌在种植体表面黏附和定植的最适管径,为研制开发具有抗菌性能的种植体提供实验基础。采用阳极氧化法,设定不同氧化电压,在Ti2448合金表面生成具有不同纳米管径的生物活性膜。通过MTT实验检测不同管径纳米管表面在不同时间点黏附的MG-63细胞数量差异;通过免疫荧光法观察接种24h后不同管径纳米管表面黏附细胞形态学差异。结果显示,细胞接种3h和24h后,30nm组的OD值显著高于对照组及其他实验组(P0.05);随着纳米管径的增加,细胞骨架蛋白的铺展范围逐渐减小,细胞由多角形渐变为梭形、椭圆形、圆形。研究结果表明,30nm管径生物活性膜更有利于成骨细胞的早期黏附,可能更能抵抗细菌在钛种植体上的黏附与定植。     

金纳米棒的表面修饰及其应用于肿瘤诊疗的研究进展

金纳米棒具有独特的光学性质、表面易修饰性、较低的生物毒性和良好的生物相容性,因而在成像、光热治疗和药物载带等方面具有极高的潜在应用价值.本文综述了典型的金纳米棒表面修饰方法及其在生物成像、光热治疗和药物治疗中的应用,重点阐述了通过金纳米棒同时实现肿瘤诊断和治疗相结合的研究进展.     

地黄对于糖尿病大鼠微炎症状态的作用

目的:研究地黄对于糖尿病模型大鼠血糖以及微炎症状态的作用。方法:采用高糖高脂饲料喂养加腹腔注射链尿佐菌素(STZ)破坏胰岛细胞的方法构建糖尿病大鼠模型。将大鼠分为空白对照组、糖尿病模型组与药物治疗组。空白对照组以及糖尿病模型组给予蒸馏水,用药组分别给予不同剂量丹参、地黄、格列本脲灌胃治疗,每日一次,连续60日。应用血糖仪动态监测血糖,ELISA法检测血清中超敏C反应蛋白(Hs-CRP)、白细胞介素6(IL-6)、肿瘤坏死因子α(TNF-α)浓度变化情况,以观察地黄对血糖及糖尿病微炎症状态的改善效果。结果:造模成功后,糖尿病大鼠血糖明显升高(P0.05),血液中炎症因子Hs-CRP、IL-6、TNF-α含量升高,与空白对照组相比,差异显著(P0.05)。地黄治疗后血糖明显降低(P0.05),血液中炎症因子Hs-CRP、IL-6、TNF-α含量均显著减低,差异均有统计学意义(P0.05)。结论:地黄可以明显降低糖尿病大鼠的血糖水平,显著改善糖尿病大鼠的微炎症状态。     

海藻酸钠壳聚糖微球作为药物载体的研究进展

海藻酸钠壳聚糖微球是具有生物粘附性且能结合和传递大分子药物的天然高分子材料,且在生物医学领域具有广阔应用前景的药物载体。它具有生物黏附性、生物相容性、生物可降解性、对人体无毒性且能够结合和传递大分子药物的天然高分子材料。海藻酸钠壳聚糖微球作为载药微球具有提高药物的生物利用度、延长药物的作用时间等优点。国内外近些年已将其应用于药剂学领域,以及将其作为药物载体经微球化与药物结合形成给药系统的研究也在逐步开展并取得了较多成果。本文主要阐述海藻酸钠壳聚糖微球的主要生物特性、作用特点及其在医学领域中应用的研究进展,并对其应用前景进行探讨。     

Response of MG63 Osteoblast Cells to Surface Modification of Ti-6Al-4V Implant Alloy by Laser Interference Lithography

The response of human osteoblast-like osteosarcoma cells (MG63) to surface modification of Ti-6Al-4V implant alloy was investigated by Laser Interference Lithography (LIL).In this work,laser interference lithography was employed to fabricate the microstructures of grooves,dots and dimples onto the surfaces of Ti-6Al-4V samples.Two and three beam LIL systems were developed to carry out the experiments.The laser treatment resulted in the increases of the roughness and the contact angle of water on the implant alloy surfaces.The proliferation of osteoblasts was analyzed by MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide) assay for the time periods of 4 hours,2 days,3 days,and 6 days.The MTT test results demonstrated that the laser treatment surfaces had a positive impact on the proliferation of osteoblast cells after 24 hours.The alloy surface morphology and the morphological changes of MG63 cells cultured on the laser textured Ti-6Al-4V surface were observed by Scanning Electron Microscope (SEM).The SEM results indicated that the osteoblast cells were aligned on grooved surfaces and they were prolonged with the structures.Enzymatic detachment results showed that the 20 μm grooved structures provided the better cell adhesion to the textured Ti-6Al-4V surfaces.     

Modification of the Microtiter Reading Mirror for Use in the Standardized Micro Complement Fixation Test

Modification of the Microtiter reading mirror used in the standardized diagnostic complement fixation method permits convenient estimation of the results in per cent hemolysis by direct visual comparison with the hemolytic standards.     

Periodate oxidation of polysaccharides for modification of chemical and physical properties

A limited degree (typically 1-20%) of periodate oxidation of polysaccharides may give rise to derivatives with entirely altered chemical and physical properties. Notably, the ring opening caused by periodate leads to the formation of highly flexible ‘hinges’ in otherwise rather semiflexible or rigid structures. This review highlights selected examples with the main focus on periodate oxidation of alginates, chitosans, hyaluronan, scleroglucan/schizophyllan, and cellulose.     

Tailoring the biological response of zirconium implants using zirconia bioceramic coatings: A systematic review

BackgroundThe poor biological performance of zirconium implants in the human body resulting from their bio-inertness and vulnerability to corrosion and bacterial activity reflects the need for further studies on substitution or performing the surface modification. The suggestion of employing zirconia (ZrO₂) bioceramic coatings for surface modification seems beneficial.ObjectivesThis systematic review aims to identify and summarize existing documents reporting the biological responses for ZrO₂ coatings produced by the PEO process on zirconium implants.MethodsPubMed, Scopus, and Web of Science international databases were searched for the original and English-language studies published between 2000 and 2021. All publications reported at least one study about in-vitro (cellular and immersion studies), in-vivo (animal studies), and antibacterial topics for ZrO₂-PEO coated zirconium implants.ResultsThroughout the initial search, 496 publications were found, and 296 papers remained following the elimination of duplicates. Finally, after multiple screening and eligibility assessments, 25 publications were qualified and included in the review. Among them, 25 in-vitro (cellular and immersion in SBF and Hanks’ solutions studies), one in-vivo (animal studies), and eight antibacterial studies were found.ConclusionThe ZrO₂ coated samples demonstrate no cytotoxicity, high cell viability rate, and excellent biocompatibility. However, changing the solution composition and electrical parameters during the PEO procedures result in significant changes to in-vitro responses. As an instance, the ZrO₂ coating surface demonstrates greater biocompatibility after irradiated by UV, which makes the surface more suitable for cell growth. Due to weak apatite-forming ability, the zirconium sample shows low bioactivity in SBF. However, most cases (13 out of 16) show that the specific morphology and chemical composition of the ZrO₂ coating promote apatite-forming ability with good bioactivity in SBF. Nevertheless, few papers (three out of 16) showed that the ZrO₂ coatings immersed in SBF had no apatite precipitates and so no bioactivity. These cases limit the bioactivity enhancement to treatment by UV-light irradiation, hydrothermal and chemical treatment, thermal evaporation, and cathodic polarization post-treatment on ZrO₂ coatings. Both zirconium and ZrO₂ coated samples do not show apatite-forming ability in Hanks’ solution. The ZrO₂ coated implant with the bone together indicates a greater shear strength and rapid new bone formation ability during 12 weeks because of containing Ca-P compounds and porous structure. The UV post-treated ZrO₂ coating induces faster new bone formation and firmer connection of bond with bone than those of untreated ZrO₂ coatings. A stronger antibacterial activity of ZrO₂ coatings is confirmed in half of the selected papers (four out of eight studies) compared to the bare zirconium samples. The antibacterial protection of ZrO₂ coatings can be influenced by the PEO procedure variables, i.e., solution composition, electrical parameters, and treatment time. In three cases, the antibacterial activity of ZrO₂ coatings is enhanced by deposition of Zn, Ag, or Cu antibacterial layers through thermal evaporation post-treatment.     

Epr Evidence for the Oxidation-Induced Formation of Negatively Charged Species on the Low-Density Lipoprotein Surface

Oxidation-induced increase of the net negative charge on low-density lipoprotein was studied by electro-phoretic mobility and by electron paramagnetic resonance. The negative-charge increase is associated not only with neutralization of the lysine residues of apoprotein B, but also with the exposition of the excessive negatively charged residues on the lipoprotein surface. The accumulation of the negatively charged residues is believed to be brought about by the conformational change of apoprotein B, triggered by neutralization of lysines and cleavage of peptide bonds. Alternatively, reactive oxygen species could also convert histidine to aspartic acid and proline to glutamic acid.     

Epr Evidence for the Oxidation-Induced Formation of Negatively Charged Species on the Low-Density Lipoprotein Surface

Oxidation-induced increase of the net negative charge on low-density lipoprotein was studied by electro-phoretic mobility and by electron paramagnetic resonance. The negative-charge increase is associated not only with neutralization of the lysine residues of apoprotein B, but also with the exposition of the excessive negatively charged residues on the lipoprotein surface. The accumulation of the negatively charged residues is believed to be brought about by the conformational change of apoprotein B, triggered by neutralization of lysines and cleavage of peptide bonds. Alternatively, reactive oxygen species could also convert histidine to aspartic acid and proline to glutamic acid.     

分枝PEI 修饰的PLGA 纳米粒转染DNA 的研究*

目的:建立基于聚(乳酸-羟基乙酸)纳米粒(PLGA)载DNA的基因转染体系,比较用空白聚(乳酸-羟基乙酸)纳米粒(PLG-A-E)吸附质粒DNA和用分枝PEI修饰后的PLGA纳米粒(PLGA-BPEI)吸附质粒DNA优缺点。方法:用乳化蒸发法制备纳米粒,对纳米粒进行表征研究,包括包封率、Zeta电位、粒径大小、稳定性,用荧光显微镜观察它们对NIH3T3和HEK293细胞的转染效率,用MTT检测对它们细胞的毒性。结果:制备了两种基于PLGA的纳米粒,PLGA-E和PLGA-BPEI粒径大小为200-270nm,zeta电位为0-30mV,在血清和不同的pH值时两者均较稳定,转染效率PLGA-BPEI较PLGA-E高,且释放时间早,但前者较后者对细胞毒性大。结论:这两种基于PLGA纳米粒均能有效转染质粒DNA,它们存在不同的优缺点,应根据不同需要进行选择。