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Journal: Journal of biomedical materials research. Part B, Applied biomaterials


Bone is a nanocomposite composed of organic (mainly collagen) and inorganic (nanocrystalline hydroxyapatite) components, with a hierarchical structure ranging from nano- to macroscale. Its functions include providing mechanical support and transmitting physio-chemical and mechano-chemical cues. Clinical repair and reconstruction of bone defects has been conducted using autologous and allogeneic tissues and alloplastic materials, with functional limitations. The design and development of biomaterial scaffolds that will replace the form and function of native tissue while promoting regeneration without necrosis or scar formation is a challenging area of research. Nanomaterials and nanocomposites are promising platforms to recapitulate the organization of natural extracellular matrix for the fabrication of functional bone tissues because nanostructure provides a closer approximation to native bone architecture. Nanostructured scaffolds provide structural support for the cells and regulate cell proliferation, differentiation, and migration, which results in the formation of functional tissues. Unique properties of nanomaterials, such as increased wettability and surface area, lead to increased protein adsorption when compared with conventional biomaterials. Cell-scaffold interactions at the cell-material nanointerface may be mediated by integrin-triggered signaling pathways that affect cell behavior. The materials selection and processing techniques can affect the chemical, physical, mechanical, and cellular recognition properties of biomaterials. In this article, we focused on reviewing current fabrication techniques for nanomaterials and nanocomposites, their cell interaction properties and their application in bone tissue engineering and regeneration. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.

Concepts: Bone, Collagen, Extracellular matrix, Nanomaterials, Tissue engineering, Materials science, Tissue, Nanocomposite


Comprehensive studies comparing tensile properties of sutures are over 25 years old and do not include recent advances in suture materials. Accordingly, the objective of this article is to investigate the tensile properties of commonly used sutures in cutaneous surgery. Thirteen 3-0 sized modern sutures (four nonabsorbable and nine absorbable) were tensile tested in both straight and knotted configurations according to the procedures outlined by the United States Pharmacopeia. Glycomer 631 was found to have the highest failure load (56.1 N) of unknotted absorbable sutures, while polyglyconate (34.2 N) and glycomer 631 (34.3 N) had the highest failure loads of knotted absorbable sutures. Nylon (30.9 N) and polypropylene (18.9 N) had the greatest failure loads of straight and knotted nonabsorbable sutures, respectively. Polydioxane was found to have the most elongation prior to breakage (144%) of absorbable sutures. Silk (8701 MPa) and rapid polyglactin 910 (9320 MPa) had the highest initial modulus of nonabsorbable and absorbable sutures, respectively. The new data presented in the study provide important information for guiding the selection of suture materials for specific surgeries. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2014.

Concepts: United States, Surgery, Polypropylene, Tensile strength, Surgical suture, Young's modulus, Silk, United States Pharmacopeia


Biocompatibility, injectability and in situ self-setting are characteristics of calcium phosphate cements which make them promising materials for a wide range of clinical applications in traumatology and maxillo-facial surgery. One of the main disadvantages is their relatively low strength which restricts their use to nonload-bearing applications. α-Tricalcium phosphate (α-C3 P) cement sets into calcium-deficient hydroxyapatite (CDHA), which is biocompatible and plays an essential role in the formation, growth and maintenance of tissue-biomaterial interface. β-Dicalcium silicate (β-C2 S) and tricalcium aluminate (C3 A) are Portland cement components, these compounds react with water to form hydrated phases that enhance mechanical strength of the end products. In this study, setting time, compressive strength (CS) and in vitro bioactivity and biocompatibility were evaluated to determine the influence of addition of β-C2 S and C3 A to α-C3 P-based cement. X-ray diffraction and scanning electron microscopy were used to investigate phase composition and morphological changes in cement samples. Addition of C3 A resulted in cements having suitable setting times, but low CS, only partial conversion into CDHA and cytotoxicity. However, addition of β-C2 S delayed the setting times but promoted total conversion into CDHA by soaking in simulated body fluid and strengthened the set cement over the limit strength of cancellous bone. The best properties were obtained for cement added with 10 wt % of β-C2 S, which showed in vitro bioactivity and cytocompatibility, making it a suitable candidate as bone substitute. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2014.

Concepts: Calcium, Materials science, Strength of materials, Compressive strength, Physical compression, Portland cement, Cement, Tricalcium aluminate


Nano/microfibrous polymeric constructs present various inherent advantages, such as highly porous architecture and high surface to volume ratio, making them attractive for tissue engineering purposes. Electrospinning is the most preferred technique for the fabrication of polymeric nanofibrous assemblies that can mimic the physical functions of native extracellular matrix greatly favoring cells attachment and thus influencing their morphology and activities. Different approaches have been developed to apply polymeric microfiber fabrication techniques (e.g. wet-spinning) for the obtainment of scaffolds with a three-dimensional network of micropores suitable for effective cells migration. Progress in additive manufacturing technology has led to the development of complex scaffold’s shapes and microfibrous structures with a high degree of automation, good accuracy and reproducibility. Various loading methods, such as direct blending, coaxial electrospinning and microparticles incorporation, are enabling to develop customized strategies for the biofunctionalization of nano/microfibrous scaffolds with a tailored kinetics of release of different bioactive agents, ranging from small molecules, such as antibiotics, to protein drugs, such as growth factors, and even cells. Recent activities on the combination of different processing techniques and loading methods for the obtainment of biofunctionalized polymeric constructs with a complex multiscale structure open new possibilities for the development of biomimetic scaffolds endowed with a hierarchical architecture and a sophisticated release kinetics of different bioactive agents. This review is aimed at summarizing current advances in technologies and methods for manufacturing nano/microfibrous polymeric constructs suitable as tissue engineering scaffolds, and for their combination with different bioactive agents to promote tissue regeneration and therapeutic effects. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2014.

Concepts: DNA, Protein, Extracellular matrix, Cell biology, Cellular differentiation, Regeneration, Engineering, Scaffolding


In this paper, we reported the results of our efforts in developing DCPA/nanosilica composite orthopedic cement. It is motivated by the significances of DCPA and silicon in bone physiological activities. More specifically, this paper examined the effects of various experimental parameters on the properties of such composite cements. In this work, DCPA cement powders were synthesized using a microwave synthesis technique. Mixing colloidal nanosilica directly with synthesized DCPA cement powders can significantly reduce the washout resistance of DCPA cement. In contrast, a DCPA-nanosilica cement powder prepared by reacting Ca(OH)2 , H3 PO4 and nanosilica together showed good washout resistance. The incorporation of nanosilica in DCPA can improve compressive strength, accelerate cement solidification, and intensify surface bioactivity. In addition, it was observed that by controlling the content of NaHCO3 during cement preparation, the resulting composite cement properties could be modified. Allowing for the development of different setting times, mechanical performance and crystal features. It is suggested that DCPA-nanosilica composite cement can be a potential candidate for bone healing applications. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B, 2014.

Concepts: Orthopedic surgery, Synthesis, Strength of materials, Compressive strength, Physical compression, Portland cement, Powder, Cement


A common and prevailing complication for patients with abdominal surgery is the peritoneal adhesion that follows during the post-operative recovery period. Biodegradable polymers have been suggested as a barrier to prevent the peritoneal adhesion. In this work, as a preventive method, PVA/Gelatin hydrogel-based membrane was investigated with various combinations of PVA and gelatin (50/50, 30/70/, and 10/90). Membranes were made by casting method using hot PVA-gelatin solution and the gelatin was cross-linked by exposing UV irradiation for 5 days to render stability of the produced sheathed form in the physiological environment. Physical crosslinking was chosen to avoid the problems of potential cytotoxic effect of chemical crosslinking. Their materials characterization and mechanical properties were evaluated by SEM surface characterization, hydrophilicity, biodegradation rate, and so forth. Cytocompatibility was observed by in vitro experiments with cell proliferation using confocal laser scanning microscopy and the MTT assay by L-929 mouse fibroblast cells. The fabricated PVA/Gel membranes were implanted between artificially defected cecum and peritoneal wall in rats and were sacrificed after 1 and 2 weeks post-operative to compare their tissue adhesion extents with that of control group where the defected surface was not separated by PVA/Gel membrane. The PVA/Gel membrane (10/90) significantly reduced the adhesion extent and showed to be a potential candidate for the anti-adhesion application. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.

Concepts: Collagen, Fibroblast, Polymer chemistry, Cytotoxicity, MTT assay, Elastomer, Cross-link, Cross-linked polyethylene


Nitinol-based vascular devices, for example, peripheral and intracranial stents, are limited by thrombosis and restenosis. To ameliorate these complications, we developed a technology to promote vessel healing by rapidly seeding (QuickSeeding) autologous blood-derived endothelial cells (ECs) onto modified self-expanding nitinol stent delivery systems immediately before implantation. Several thousand micropores were laser-drilled into a delivery system sheath surrounding a commercial nitinol stent to allow for exit of an infused cell suspension. As suspension medium flowed outward through the micropores, ECs flowed through the delivery system attaching to the stent surface. The QuickSeeded ECs adhered to and spread on the stent surface following 24-h in vitro culture under static or flow conditions. Further, QuickSeeded ECs on stents that were deployed into porcine carotid arteries spread to endothelialize stent struts within 48 h (n = 4). The QuickSeeded stent struts produced significantly more nitric oxide in ex vivo flow circuits after 24 h, as compared to static conditions (n = 5). In conclusion, ECs QuickSeeded onto commercial nitinol stents within minutes of implantation spread to form a functional layer in vitro and in vivo, providing proof of concept that the novel QuickSeeding method with modified delivery systems can be used to seed functional autologous endothelium at the point of care. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2015.

Concepts: Atherosclerosis, Blood vessel, In vivo, Stent, Endothelium, In vitro, Nitric oxide, Vasodilation


The research on artificial nerve conduits has become a focus of study in peripheral nerve reconstruction so as a possible replacement for the treatment of autologous nerve grafts in clinics. In this study, we used longitudinally oriented collagen conduit (LOCC) combined with nerve growth factor (NGF) to reconstruct long distance of sciatic nerve defects (35 mm) in adult dog model. The long term follow-up evaluation demonstrated that the LOCC/NGF conduit allowed functional and morphological nerve regeneration at the transection site of the injured sciatic nerve. Furthermore, the functional study confirmed that when NGF was loaded onto LOCC it promoted a better recovery of regenerated axons than LOCC alone. The gastrocnemius muscle mass in the LOCC/NGF group was significantly greater than in the LOCC alone group. The results indicated that when LOCC conduit combined with NGF it would provide a preferential environment for sciatic nerve regeneration. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2017.

Concepts: Muscle, Action potential, Sciatic nerve, Sciatica, Nerve, Nerve growth factor, Conduit


Polypropylene meshes, originally introduced for hernia repair, are presently utilized in several anatomical sites. Several million are implanted annually worldwide. Depending on the device, up to 10% will be excised to treat complications. The excised meshes can provide material to study the complications, however, they have remained underutilized over the last decades and the mechanisms of complications continue to be incompletely understood. The fundamental question as to whether polypropylene degrades in vivo is still debated. We have examined 164 excised meshes using conventional microscopy to search for features of polypropylene degradation. Four specimens were also examined by transmission electron microscopy. The degraded material, detected by its ability to absorb dyes in the degradation nanopores, formed a continuous layer at the surface of the mesh fibers. It retained birefringence, inclusions of non-degraded polypropylene, and showed ability to meld with the non-degraded fiber core when heated by the surgical cautery. Several features indicated that the degradation layer formed in vivo: inflammatory cells trapped within fissures, melting caused by cautery of excision surgery, and gradual but progressive growth of the degradation layer while in the body. Cracking of the degraded material indicated a contribution to clinically important mesh stiffening and deformation. Chemical products of degradation need to be analyzed and studied for their role in the mesh-body interactions. The described methods can also be used to study degradation of other materials. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2015.

Concepts: Electron, Biology, Surgery, Microscope, Hernia, Transmission electron microscopy, Excision


Recapitulating long bone repair through endochondral ossification (EO) is increasingly becoming a more popular approach. A successful EO Process depends greatly on the establishment of a healthy hypertrophic-cartilage template (HCT). The aim of this work is to design a hydrogel system, which closely mimics the extracellular matrix of HCT. We examined the combinatorial effect of two commonly used hydrogels for bone and cartilage regeneration strategies, hyaluronan (HA) and fibrin (FB), to induce HCT formation. Hydrogel combinations were evaluated using a clinically relevant cell source, human bone marrow mesenchymal stem cells (hBMSCs). The results establish that with increasing HA (50-90%) the chondrogenic and its subsequent hypertrophy trend improved, with 70:30 HA:FB combination showing the highest and most uniform expression of chondrogenic and hypertrophic stage specific markers. This combination also showed superior support for cell micro-aggregation and differentiation. Thus, 70:30 HA-FB matrix demonstrated a healthy formation of chondrogenic and hypertrophic stages with rich stage-specific ECM components. This study demonstrates that with the appropriate hydrogel design it is possible to develop effective tissue engineering therapies for bone defect repair and regeneration through endochondral ossification by establishing a healthy HCT. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2017.

Concepts: Extracellular matrix, Stem cell, Mesenchymal stem cell, Bone marrow, Cellular differentiation, Cartilage, Intramembranous ossification, Osteoblast