Comparison of human alveolar osteoblasts cultured on polymer-ceramic composite scaffolds and tissue culture plates

The effects of medical grade polycaprolactone-tricalcium phosphate (mPCL-TCP) (80:20) scaffolds on primary human alveolar osteoblasts (AOs) were compared with standard tissue-culture plates. Of the seeded AOs, 70% adhered to and proliferated on the scaffold surface and within open and interconnected pores; they formed multi-layered sheets and collagen fibers with uniform distribution within 28 days. Elevation of alkaline phosphatase activity occurred in scaffold-cell constructs independent of osteogenic induction. AO proliferation rate increased and significant decrease in calcium concentration of the medium for both scaffolds and plates under induction conditions were seen. mPCL-TCP scaffolds significantly influenced the AO expression pattern of osterix and osteocalcin (OCN). Osteogenic induction down-regulated OCN at both RNA and protein level on scaffolds (3D) by day 7, and up-regulated OCN in cell-culture plates (2D) by day 14, but OCN levels on scaffolds were higher than on cell-culture plates. Immunocytochemical signals for type I collagen, osteopontin and osteocalcin were detected at the outer parts of scaffold-cell constructs. More mineral nodules were found in induced than in non-induced constructs. Only induced 2D cultures showed nodule formation. mPCL-TCP scaffolds appear to stimulate osteogenesis in vitro by activating a cellular response in AO's to form mineralized tissue. There is a fundamental difference between culturing AOs on 2D and 3D environments that should be considered when studying osteogenesis in vitro.     

Lysophosphatidic acid modulates the healing responses of human periodontal ligament fibroblasts and enhances the actions of platelet-derived growth factor

BACKGROUND: Platelet-derived growth factor (PDGF) has been used to promote healing in many in vitro and in vivo models of periodontal regeneration. PDGF interacts extensively with lysophosphatidic acid (LPA). We recently showed that LPA modulates the responses of human gingival fibroblasts to PDGF. The objectives of this study were as follows: 1) to evaluate the basic interactions of LPA with primary human periodontal ligament fibroblasts (PDLFs) alone and with PDGF-BB for promoting PDLF growth and migration; 2) to determine the effects in an in vitro oral wound-healing model; and 3) to identify the LPA receptors (LPARs) expressed by PDLF. METHODS: PDLF regenerative responses were measured using 1 and 10 microM LPA in the absence or presence of 1 or 10 ng/ml PDGF. Cell proliferation was determined by 5-bromo-2'-deoxyuridine (BrdU) immunohistochemistry and by cell counting. Migration responses were measured using a microchemotaxis chamber. PDLFs were grown to confluence on glass slides, a 3-mm-wide wound was mechanically inflicted, and wound fill on days 4, 6, and 9 was reported. PDLF LPAR expression was determined using Western blotting. RESULTS: PDLFs exhibited proliferative and chemotactic responses to LPA; these responses were enhanced when LPA and PDGF were present together. LPA plus PDGF elicited complete wound fill. PDLFs express the LPARs LPA(1), LPA(2), and LPA(3). CONCLUSIONS: To our knowledge, this study provides the first evidence that LPA stimulates human PDLF wound healing responses and interacts positively with PDGF to regulate these actions. These results suggest that LPA and its receptors play important modulatory roles in PDLF regenerative biology.     

辛伐他汀/聚己内酯静电纺丝膜的制备及其生物相容性评价

目的：制备辛伐他汀（simvastatin）/聚己内酯（Polycaprolactone,PCL）静电纺丝膜,评价其生物相容性.方法：制备PCL静电纺丝膜和simvastatin/PCL静电纺丝膜,通过扫描电镜观察两种膜片的形貌特征.选择人牙周膜成纤维细胞（periodontal ligament fibroblasts,PDLFs）与膜片浸提液共培养,检测细胞增殖情况,评价材料毒性;PDLFs接种于膜片共培养7d,扫描电镜观察细胞生长情况,以直接接触法检测膜片的细胞毒性.将PCL和simvastatin/PCL静电纺丝膜植入大鼠皮下,术后14d取出标本,HE和Masson染色法进行组织学观察.结果：成功制备出纤维直径为纳米级别的simvastatin/PCL静电纺丝膜.细胞增殖试验和直接接触试验结果显示,PCL和simvastatin/PCL静电纺丝膜的浸提液细胞毒性试验均合格,细胞在材料上伸展充分,连接成片.PCL和simvastatin/PCL静电纺丝膜植入皮下2周后均有包膜形成;与PCL静电纺丝膜相比,simvastatin/PCL静电纺丝膜与周围组织界限较明显,反应层炎症细胞较少.结论：simvastatin/PCL静电纺丝膜的生物相容性良好,细胞毒性和组织相容性均符合生物支架材料的要求.     

组织工程化人形下颌骨髁状突的实验研究

目的　评价采用组织工程技术构建人下颌骨髁状突软骨复合组织的可行性。方法　以可降解生物材料聚羟基乙酸 (polyglycolicacid ,PGA) /聚乳酸 (polylacticacid ,PLA)预制人下颌骨髁状突模型 ,体外培养扩增牛骨膜成骨细胞和牛关节表面软骨。实验分 3组 :第 1组 ,模型内仅注入 1.5 %藻酸钙和 30 %氧化乙丙烯 ;第 2组 ,模型内分别注入成骨细胞和软骨细胞悬液 ,浓度为 5× 10 7/ml;第 3组 ,模型内接种成骨细胞藻酸钙悬液 ,同时在模型关节表面涂敷软骨细胞 PluronicF12 7悬液 ,浓度为 5× 10 7/ml。分别植入裸鼠皮下 ,12周后取材 ,作大体和组织学观察。结果　第 1组无骨和软骨形成 ,模型支架明显缩小 ,形态不规则 ;第 2组仅留残缺不全的组织结构 ,标本体积缩小变形 ;第 3组形态结构与原植入模型支架相同 ,组织学观察有骨和软骨组织结构 ,两者界面连接有序 ,骨组织内有大量新生骨板。结论　以人工合成生物材料预制人下颌骨髁状突支架 ,采用组织工程技术 ,可以在裸鼠体内构建具有骨软骨复合结构的正常形态的人形下颌骨髁状突 ,从而为进一步临床应用提供了理论依据     

颞颌关节关节盘再造的研究

目的：用组织工程方法进行颞颌关节关节盘的再造。方法：用Ⅱ型胶原酶消化法收集兔耳廓软骨细胞，将细胞按5×10^7／ml的终浓度接种于纤维蛋白原中，固化成为膜片状后，将负载软骨细胞的纤维蛋白植入裸鼠背部皮下组织中，2个月后取材，通过大体标本观察、组织学观察颞颌关节关节盘的构建情况。结果：植入术后2个月，在裸鼠背部形成了膜片状的组织，为亮白色，具有一定的弹性和韧性；组织学检查见新形成的组织由软骨构成，纤维蛋白己完全吸收。结论：纤维蛋白负载软骨细胞，可以有效进行颞颌关节关节盘的再造。     

Reconstruction of mandibular defects with autologous tissue-engineered bone.

PURPOSE: Maxillofacial reconstructive procedures often require bone graft harvesting, which results in donor site morbidity; the use of tissue-engineered bone would eliminate this problem. In this study, a novel scaffold design and new fabrication protocol were used to produce autologous tissue-engineered constructs (scaffolds seeded with cells) to reconstruct segmental mandibular defects in a minipig model. MATERIALS AND METHODS: Porcine mesenchymal stem cells were isolated from the ilium. They were expanded in culture and seeded onto poly-dl-lactic-coglycolic acid scaffolds. The constructs were placed in a bioreactor and incubated for 10 days in medium and osteogenic supplements. Four full-thickness bony defects (2 x 2 cm) were created in the same pig's mandible. The constructs (n = 2) were placed into 2 of the defects as autologous grafts. One unseeded scaffold and 1 empty defect served as controls. At 6 weeks postimplantation, the pig was sacrificed, the mandible was harvested, and the grafted sites were evaluated by clinical, radiographic, and histologic methods. RESULTS: The construct-implanted defects appeared to be filled with hard tissue resembling bone, whereas controls were filled with fibrous tissue. Radiographically, the tissue-engineered constructs were uniformly radiodense with bone distributed throughout. The interface between native bone and constructs was indistinct. Complete bone ingrowth was not observed in control defects. Osteoblasts, osteocytes, bone trabeculae, and blood vessels were identified throughout the defects implanted with constructs. CONCLUSION: This "proof-of-principle" study indicates that porcine mandibular defects can be successfully reconstructed by in vitro cultured autologous porcine mesenchymal stem cells on a biodegradable polymer scaffold with penetration of bone and blood vessels.     

脂肪干细胞和纤维蛋白胶快速构建人工皮肤修复创面的研究

目的:探讨绿色荧光蛋白(GFP)转基因小鼠脂肪组织来源干细胞(ADSCs)与纤维蛋白胶复合快速成型构建组织工程皮肤替代物修复皮肤缺损的可行性.方法:采用胶原酶消化GFP小鼠脂肪组织,获得GFP小鼠脂肪干细胞(ADSCs),并证明其具有成骨和成脂的多向分化能力,经体外扩增后复合纤维蛋白胶快速成型构建组织工程活性皮肤替代物.15 只C57鼠随机分成3组:ADSCs复合纤维蛋白胶组织工程活性皮肤替代物实验组、单纯纤维蛋白胶移植组和空白对照组.将各组相应材料分别移植于C57BL小鼠背部皮肤缺损处,比较观察创面修复效果.结果:分离的细胞具有不断的增殖能力,并具有多向分化潜能.同种异体移植后,免疫荧光检测创面有大量GFP小鼠脂肪干细胞存活.ADSCs复合纤维蛋白胶可以缩短创面愈合时间.组织学观察显示,ADSCs复合纤维蛋白胶实验组上皮形成较厚,真皮层胶原纤维排列有序,成纤维细胞数量较单纯纤维蛋白胶移植组和空白对照组明显增多.结论:GFP-ADSCs复合纤维蛋白胶构建的组织工程皮肤替代物移植后可加速小鼠皮肤创面愈合,提示以ADSCs作为种子细胞复合纤维蛋白胶快速成型构建的组织工程皮肤可用于皮肤缺损的修复治疗.     

成年兔成纤维细胞在纤维蛋白胶表面生长的初步观察

目的:观察成纤维细胞(Fibroblast,FB)复合在纤维蛋白胶表面后,成纤维细胞的生长状态。方法:体外分离、培养、鉴定成年兔皮肤成纤维细胞,并通过倒置显微镜、光学显微镜对成纤维细胞在纤维蛋白胶表面的生长情况进行形态学观察,免疫组化方法检测细胞波形蛋白及角蛋白的表达,鉴定细胞。采用SPSS12.0软件包对数据进行统计学分析。结果:兔成纤维细胞在纤维蛋白胶表面铺展形态佳,增殖速度快。细胞生长2～4h贴壁,3d时细胞呈漩涡状,基本完全融合,约5d后细胞逐渐呈复层生长。免疫组化波形蛋白阳性,角蛋白阴性,差异有显著性(P<0.05),证实细胞来源可靠。结论:兔成纤维细胞在纤维蛋白胶表面生长、增殖良好,纤维蛋白胶有望成为成纤维细胞生长的支架材料。     

Tissue-engineered composites of bone and cartilage for mandible condylar reconstruction.

PURPOSE: This study evaluated the feasibility of creating a tissue-engineered adult human mandible condyle composite of bone and cartilage. MATERIALS AND METHODS: A polymer template composed of polyglycolic acid (PGA) and polylactic acid (PIA), and formed in the shape of the human mandible condyle, was seeded with osteoblasts isolated from a bovine periosteum suspended in calcium alginate. Chondrocytes isolated from the same calf suspended in 30% pluronic were then "painted" onto the articular surface of the scaffold, and it was then implanted into subcutaneous pockets on the dorsum of athymic mice. Animals were divided into 3 groups: group I (n = 6) received a PGA/PLA scaffold saturated with hydrogels not containing cells; group II (n = 6) received scaffolds seeded with both cell types suspended in saline rather than hydrogels; and group III (n = 6) received scaffolds seeded with both cell types suspended in hydrogel composites. Constructs were harvested after 12 weeks and evaluated grossly and microscopically by using histologic stains. RESULTS: In group I, the constructs formed a small mass without evidence of new bone or cartilage. In group II, the constructs were small and irregular. Microscopically they contained scattered islands of bone and cartilage. All specimens in group III retained their original condylar shape and were quite firm. Microscopic evaluation indicated trabecular bone interfacing with hyaline cartilage on the articulating surface. CONCLUSION: These findings show that the composites of bone and cartilage can be engineered to serve as condylar substitutes. The interdigitation of bone and cartilage at their interface is similar to the normal interface of these composite tissues seen in articulating joints.     

Novel isolation of alkaline phosphatase-positive subpopulation from periodontal ligament fibroblasts

BACKGROUND: Periodontal ligament fibroblasts (PDLFs) are the cells essential for periodontal regeneration. PDLFs comprise a heterogeneous cell population and consist of several cell subsets that differ in their function. It is known that PDLFs produce osteoblast-related extracellular matrix proteins and show higher alkaline phosphatase (ALP) activity compared with gingival fibroblasts (GFs), implying that PDLFs have osteogenic characterisitics. The aim of the present study was to isolate the osteogenic population of PDLFs according to their expression of ALP. METHODS: PDLFs and gingival fibroblasts were separated into two populations, ALP-positive and ALP-negative, with an immunomagnetic method using a monoclonal antibody against human bone type ALP and magnetic beads conjugated with a secondary antibody. Expression of basic fibroblast growth factor (bFGF) receptor and transforming growth factor (TGF)-beta receptor was investigated in these two populations. Osteoblast-related molecules, osteocalcin, and bone sialoprotein; ALP activity; and effect of bFGF on proliferation were also compared. RESULTS: Effective separation was confirmed in both PDLFs and GFs by flow cytometry. The expression of FGF receptor (FGFR) and TGF-beta receptor was significantly higher in ALP-positive PDLFs than in ALP-negative PDLFs. ALP-positive PDLFs also expressed higher mRNA levels of osteocalcin and bone sialoprotein compared with ALP-negative PDLFs. The mitogenic effect of bFGF on ALP-positive PDLFs was greater than that of ALP-negative PDLFs. CONCLUSIONS: These results indicate that osteoblastic and/or cementoblastic PDLF subsets could be isolated from the PDLF populations using an immunomagnetic method. Magnetic isolation of PDLFs may be a useful tool to obtain the cells which will potentially induce mineralization on the root surface.     

三种太金属表面处理方法对牙周膜成纤维细胞附着和生长的影响

目的：比较三种不同表面处理方法对牙周膜细胞在钛金属表面附着和生长影响。方法：将三种经不同方法表面处理的钛金属（纯钛，钛75，钛表面氮化处理）试件放在12孔培养板内，取生长良好的第5代人牙周膜成纤维细胞（PDLF）接种在试件表面，分别在接种后24h和72h进行贴壁细胞计数，并在扫描电镜下观察细胞在金属表面附着情况.结果：接种24h后纯钛表面的贴壁细胞数多于钛75金属表面的细胞数（P＜0．05），但在接种后72h时这种差异消失，不论接种后24h或72h钛表面氮化处理金属表面的细胞数都明显少于另外两种金属表面的细胞数（P＜0．05），扫描电镜结果表明PDLF在纯钛和钛75表面伸展，而在钛表面氮化处理的金属表面细胞基本不伸展。结论：人PDLF在纯钛，钛75表面的生物性附着优于在表面氮化处理的钛金属表面。     

牙周膜成纤维细胞在三维静电纺丝纳米纤维支架上的培养

目的:研究人牙周膜成纤维细胞与静电纺丝聚乳酸/聚己内酯纳米纤维支架体外培养的生物相容性.方法:分离、培养人牙周膜成纤维细胞,接种在静电纺丝纳米纤维支架上,与常规培养条件下的细胞进行比较,观察生长形态、生长曲线、倍增时间及活性.结果:人牙周膜成纤维细胞生长情况与常规培养基本一致,2组间的倍增时间比较无统计学差异(P＞0.05),活细胞百分率与正常培养无明显统计学差异(P＞0.05).结论:人牙周膜成纤维细胞在三维静电纺丝纳米纤维上生长、增殖,该支架材料具有很好的生物相容性,可作为牙周膜组织工程候选支架材料.     

应用纤维蛋白胶和医用OB胶修复兔面神经损伤的实验研究

目的:探讨用纤维蛋白胶或医用OB胶修复兔面神经的损伤效果。方法:手术制作实验用健康30只新西兰大耳白兔右侧面神经下颊支损伤模型,随机分成3组,分别为显微外科吻合组(Ⅰ组)、纤维蛋白胶粘合组(Ⅱ组)、医用OB胶粘合组(Ⅲ组),分别进行修复。术后16周进行大体观察、神经电生理检测、组织学观察、图像分析,评价神经再生恢复情况。结果:16周时肉眼观察3个组吻合口处均见神经再生,可抵抗一定拉力,Ⅰ组和Ⅲ组修复神经的周围软组织粘连较Ⅱ组严重;与Ⅰ组相比,Ⅱ组轴突再生率和再生轴突恢复比均有提高。结论:纤维蛋白胶和医用OB胶均有较好的生物相容性,可修复神经损伤,纤维蛋白胶对神经损伤的修复效果更佳。     

人牙周膜成纤维细胞在纯钛表面附着的电镜观察

目的：研究人牙周膜成纤维细胞(PDLF)在纯钛金属表面的结合形式和超微结构。方法：将纯钛试件放在12孔培养板内，取生长良好的第五代人牙周膜成纤维细胞接种在试件表面，培养72h后取出，原位包埋法制作透射电镜标本，透射电镜观察。结果：人牙周膜成纤维细胞在纯钛表面附着形式不同于上皮细胞在金属表面的附着形式，细胞与金属结合界面中未观察到典型半桥粒结构。人牙周膜成纤维细胞胞浆中，细胞器发达，富含与蛋白质合成、代谢及增殖等生物学功能有关的细胞超微结构，如粗面内质网、线粒体、核糖体、细胞核等。结论：人牙周膜成纤维细胞在钛金属表面的附着形式，不同于上皮细胞的附着形式，表现为蛋白合成旺盛，可能为细胞直接附着，其具体附着形式还待进一步研究。     

Human bone marrow stroma stem cell distribution in calcium carbonate scaffolds using two different seeding methods

Objective: The aim of this study was to develop a method for the determination of the three‐dimensional (3D) distribution of cells in mineralized scaffolds and to compare the effect of two different methods of cell seeding of human bone marrow stroma cells (hBMSCs) in long‐term cultures. Materials and methods: hBMSCs were seeded into CaCO₃ scaffolds by droplet seeding using culture medium with and without the addition of fibrin. After 2, 7, 14, and 21 days of culture, the constructs were embedded into methylmethacrylate and serially sectioned using undecalcified thick section technology. Sections were serially scanned from the surface to the bottom of the scaffolds and DAPI‐stained cells were automatically counted in each section using structured illumination fluorescence microscopy (FM) with serial optical sectioning and image analysis software. Results: The data showed that the seeding efficiency was significantly higher in the scaffolds seeded with the addition of fibrin. Moreover, the number of cells increased to higher levels and remained higher for longer periods with the use of the fibrin matrix, whereas cells seeded in the medium suspension exhibited a sharp decrease after the first week of cultivation. There were distinct differences in the 3D cell distribution between the center and the periphery of the scaffolds. The use of a fibrin matrix was associated with a more uniform cell distribution 1 and 2 weeks after seeding in different levels (center vs. periphery: P>0.05), whereas cells in the medium solution group accumulated at the periphery of the scaffolds. Conclusions: In conclusion, automated serial optical sectioning using structured illumination FM can assess cell numbers and the 3D distribution of hBMSCs in mineralized scaffolds. This allows for a detailed analysis of the effect of different in vitro procedures used for cell seeding. The use of fibrin during seeding increases seeding efficiency and enhances both proliferation and cell survival in the central parts of the scaffolds. To cite this article:
Zhu H, Schulz J, Schliephake H. Human bone marrow stroma stem cell distribution in calcium carbonate scaffolds using two different seeding methods.
Clin. Oral Impl. Res. 21 , 2010; 182–188.
doi: 10.1111/j.1600‐0501.2009.01816.x     

PGA无纺网与PDLCs的3D共培养物在裸鼠体内的生长观察

目的：通过研究人牙周韧带细胞(PDLCs)与聚羟基乙酸(PGA)无纺网共培养物在裸鼠体内的生长，探讨PGA无纺网作为支架应用于牙周组织工程的可能性。方法：将共培养7d的人PDLCs与PGA无纺网复合物接种于BALB／C裸小鼠一侧背部皮下，另一侧植入空白PGA为对照。分别于1、2、3、4周取材进行大体及HE和Masson‘s染色及Ⅰ型胶原免疫组织化学观察，并进行新生毛细血管记数。结果：随着。PGA无纺网在体内的逐渐降解，PDLCs同步增殖，分泌胞外基质。体内2周时即可见实验侧植入物血管化良好并有胶原束的形成，Ⅰ型胶原表达阳性。结论：PGA无纺网具有良好的生物相容性和生物安全性，并易于新生血管的形成，作为牙周组织工程的细胞支架有良好的应用前景。     

Comparative evaluation of periodontal ligament fibroblasts stored in different types of milk: effects on viability and biosynthesis of collagen

Milk remains one of the most frequently recommended solutions for storage of avulsed teeth because it can maintain cell viability and is easily accessible. However, some negative effects of milk on avulsed teeth have been reported, just as the effects of milk on the long‐term functions of cells are not clear. This study aimed to evaluate the effects of different types of milk on the viability, proliferation, and functions of periodontal ligament fibroblasts (PDLF)s in vitro. Human PDLFs were culture‐medium depleted for 5 min and stored in Hanks’ balanced salt solution (HBSS), whole cow's milk, low‐fat cow's milk, or almond milk for 1 h at 25°C. Cell viability and proliferation were assessed using MTT assays. Expression of the genes encoding type I collagen and its modifying enzymes were analyzed using real‐time PCR. Collagen matrix production was evaluated using Picrosirius red polarization. Our results showed the overall efficiency of low‐fat cow's milk in maintaining the viability and proliferation of PDLFs, and in enhancing the process of collagen production. Almond milk storage resulted in the highest rate of PDLF proliferation, and comparable collagen biosynthesis ability to the control. Therefore, besides low‐fat cow's milk, almond milk may potentially be an alternative tooth‐storage medium for PDLF preservation and PDL tissue regeneration.     

牙周膜细胞松质骨基质支架复合移植促进牙周组织再生的研究

目的观察牙周膜细胞（PDLCs）接种松质骨基质（CBM）支架复合移植对牙周组织再生修复的影响和意义。方法将体外培养的狗自体PDLCs接种到CBM三维支架上,体外进行细胞计数和扫描电镜观察,并植人狗人工牙周组织缺损处,表面覆盖聚四氟乙烯膜（e-PTFE）,以单纯翻瓣组和只覆盖e-PTFE组作为对照。术后8周对动物组织标本进行组织学观察和测量,分析比较各组牙周组织的再生情况。结果PDLCs在CBM支架材料上形成良好的贴附并增殖,扫描电镜可见CBM具有良好的多孔网状结构,细胞在CBM上生长旺盛,伸展充分。自体PDLCs／CBM／e-PTFE膜复合植入组较单纯翻瓣组和e—PTFE组有更多的新生牙槽骨、新生牙周膜和新生牙骨质生成,且未见上皮长入。结论PDLCs接种松质骨基质支架复合移植能更有效地促进牙周组织再生和重建,CBM有望用作牙周组织工程的支架材料。     

Platelet‐rich fibrin membranes as scaffolds for periosteal tissue engineering

Objectives: Platelet‐rich fibrin (PRF)‐based membranes have been used for covering alveolar ridge augmentation side in several in vivo studies. Few in vitro studies on PRF and no studies using human periosteal cells for tissue engineering have been published. The aim is a comparison of PRF with the commonly used collagen membrane Bio‐Gide^® as scaffolds for periosteal tissue engineering. Material and methods: Human periosteal cells were seeded on membrane pieces (collagen [Bio‐Gide^®] and PRF) at a density of 10⁴ cells/well. Cell vitality was assessed by fluorescein diacetate (FDA) and propidium iodide (PI) staining, biocompatibility with the lactate dehydrogenase (LDH) test and proliferation level with the MTT, WST and BrdU tests and scanning electron microscopy (SEM). Results: PRF membranes showed slightly inferior biocompatibility, as shown by the LDH test. The metabolic activity measured by the MTT and WST tests was higher for PRF than for collagen (BioGide^®). The proliferation level as measured by the BrdU test (quantitative) and SEM examinations (qualitative) revealed higher values for PRF. Conclusion: PRF appears to be superior to collagen (Bio‐Gide^®) as a scaffold for human periosteal cell proliferation. PRF membranes are suitable for in vitro cultivation of periosteal cells for bone tissue engineering. To cite this article:
Gassling V, Douglas T, Warnke, PH, Açil Y, Wiltfang J, Becker ST. Platelet‐rich fibrin membranes as scaffolds for periosteal tissue engineering.
Clin. Oral Impl. Res. 21 , 2010; 543–549.
doi: 10.1111/j.1600‐0501.2009.01900.x