Regenerating Articular Tissue by Converging Technologies

Scaffolds for osteochondral tissue engineering should provide mechanical stability, while offering specific signals for chondral and bone regeneration with a completely interconnected porous network for cell migration, attachment, and proliferation. Composites of polymers and ceramics are often considered to satisfy these requirements. As such methods largely rely on interfacial bonding between the ceramic and polymer phase, they may often compromise the use of the interface as an instrument to direct cell fate. Alternatively, here, we have designed hybrid 3D scaffolds using a novel concept based on biomaterial assembly, thereby omitting the drawbacks of interfacial bonding. Rapid prototyped ceramic particles were integrated into the pores of polymeric 3D fiber-deposited (3DF) matrices and infused with demineralized bone matrix (DBM) to obtain constructs that display the mechanical robustness of ceramics and the flexibility of polymers, mimicking bone tissue properties. Ostechondral scaffolds were then fabricated by directly depositing a 3DF structure optimized for cartilage regeneration adjacent to the bone scaffold. Stem cell seeded scaffolds regenerated both cartilage and bone in vivo

A clinical feasibility study to evaluate the safety and efficacy of PEOT/PBT implants for human donor site filling during mosaicplasty

Mosaicplasty has become a well-accepted treatment modality for articular cartilage lesions in the knee. Postoperative bleeding remains potentially concerning. This study evaluates the porous poly(ethylene oxide)terephthalate/poly(butylene terephthalate) (PEOT/PBT) implants used for donor site filling. Empty donor sites were the controls. After 9 months, MRI, macroscopical and histological analysis were carried out. Treated defects did not cause postoperative bleeding. No adverse events or inflammatory response was observed. PEOT/PBT implants were well integrated. Empty controls occasionally showed protrusion of repair tissue at the defect margins. Surface stiffness was minimally improved compared to controls. Existing polymer fragments indicated considerable biodegradation. Histological evaluation of the filled donor sites revealed congruent fibrocartilaginous surface repair with proteoglycan-rich domains and subchondral cancellous bone formation with interspersed fibrous tissue in all implanted sites. The PEOT/PBT implants successfully reduce donor site morbidity and postoperative bleeding after mosaicplasty

Composite biomaterials with chemical bonding between hydroxyapatite filler particles and PEG/PBT copolymer matrix

In an effort to make composites from hydroxyapatite and a PEG/PBT copolymer (PolyactiveTM 70/30), chemical linkages were introduced between the filler particles and polymer matrix using hexamethylene diisocyanate as a coupling agent. Infrared spectra (IR) and thermal gravimetric analysis (TGA) confirmed the presence of PolyactiveTM 70/30 on the surface of HA filler particles. The amount of chemically bound polymer was 4.7 wt.%, as determined by TGA. The mechanical properties of the composites, that is, tensile strength and Young's modulus, were improved significantly by the introduction of a chemical linkage between the filler particles and polymer matrix compared to control composites. This method provides an effective way to introduce chemical linkage between HA filler particles and a polymer matrix. By optimizing the grafting process, a further improvement of the mechanical properties in the composites can be expected

Surface modification of nano-apatite by grafting organic polymer

Since surface properties of hydroxyapatite (HA) play an important role in its performance, surface modification of HA has gained much attention from researchers. Silane coupling agents have been the focus of the research. In this study, an effective surface modification method was developed using hexamethylene diisocyanate as a coupling agent. Polyethylene glycol (Mw=1500) was successfully coupled to the surface of nano-size apatite particles (nano-apatite). Various methods were used to characterize the surface-modified nano-apatite. Infra-red spectra confirmed the existence of a layer of polymer with both urethane and ether linkage on the surface of nano-apatite. The amount of grafted polymer as determined by total organic carbon analysis (TOC) and thermal gravimetric analysis (TGA) was about 20% in weight. Solid 1H MAS NMR spectra indicated that the amount of hydroxyl groups of nano-apatite was decreased by 7.7% after surface grafting reaction. It is concluded that the surface hydroxyl groups of nano-apatite have the reactivity towards isocyanate groups

The effect of temperature and velocity on superlubricity

Contains fulltext : 103820.pdf (preprint version ) (Open Access

Bone ingrowth in porous titanium implants produced by 3D fiber deposition

3D fiber deposition is a technique that allows the development of metallic scaffolds with accurately controlled pore size, porosity and interconnecting pore size, which in turn permits a more precise investigation of the effect of structural properties on the in vivo behavior of biomaterials. This study analyzed the in vivo performance of titanium alloy scaffolds fabricated using 3D fiber deposition. The titanium alloy scaffolds with different structural properties, such as pore size, porosity and interconnecting pore size were implanted on the decorticated transverse processes of the posterior lumbar spine of 10 goats. Prior to implantation, implant structure and permeability were characterized. To monitor the bone formation over time, fluorochrome markers were administered at 3, 6 and 9 weeks and the animals were sacrificed at 12 weeks after implantation. Bone formation in the scaffolds was investigated by histology and histomorphometry of non-decalcified sections using traditional light- and epifluorescent microscopy. In vivo results showed that increase of porosity and pore size, and thus increase of permeability of titanium alloy implants positively influenced their osteoconductive properties. (C) 2007 Elsevier Ltd. All rights reserved

Dutch Multidisciplinary Guideline on Dupuytren Disease

Purpose: To provide a comprehensive, evidence-based overview of the treatment for Dupuytren disease, specifically needle techniques, radiotherapy, primary conservative therapy, surgery, lipofilling, operative arthrolysis, salvage techniques, and the postoperative protocol and to make clinical recommendations for health care practitioners and patients. Methods: Comprehensive multidisciplinary guideline process funded by the Quality Foundation of the Dutch Federation of Medical Specialists. This process included a development, commentary, and authorization phase. Patients participated in every phase. Multiple databases and existing guidelines up to August 2020 were searched. Studies on Dupuytren disease were considered eligible. Specific eligibility criteria were described per module. To appraise the certainty of the evidence, reviewers extracted data, assessed the risk of bias, and used the Grading of Recommendations Assessment, Development and Evaluation method, where applicable. Important considerations were as follows: patient values and preferences, costs, acceptability of other stakeholders, and feasibility of implementation. Recommendations were made based on the evidence from the literature and the considerations. The primary and secondary outcome measures were defined per module based on the input of patients obtained in collaboration with the Netherlands Patient Federation and health care providers from different professions. Results: The following 8 specific modules were completed for Dupuytren disease: (1) needle techniques, (2) radiotherapy, (3) primary conservative therapy, (4) surgery, (5) lipofilling, (6) operative arthrolysis, (7) salvage techniques, and (8) the postoperative protocol. Conclusions: Our Dutch multidisciplinary guideline on Dupuytren disease provides 8 modules developed according to the standards of the Dutch Federation of Medical Specialists. Evidence-based recommendations for clinical practice are provided for needle techniques, radiotherapy, primary conservative therapy, surgery, lipofilling, operative arthrolysis, salvage techniques, and the postoperative protocol. This guideline can assist health care providers and patients in clinical practice. Type of study/level of evidence: Systematic review/I-II