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Biomaterials used in the context of tissue engineering or wound repair are commonly designed to be 'nonimmunogenic.' However, previously it has been observed that self-assembled peptide nanofiber materials are noninflammatory despite their immunogenicity, suggesting that they may be appropriate for use in wound-healing contexts. To test this hypothesis, mice were immunized with epitope-containing peptide self-assemblies until they maintained high antibody titers against the material, then gels of the same peptide assemblies were applied within full-thickness dermal wounds. In three different murine dermal-wounding models with different baseline healing rates, even significantly immunogenic peptide assemblies did not delay healing. Conversely, adjuvanted peptide assemblies, while raising similar antibody titers to unadjuvanted assemblies, did delay wound healing. Analysis of the healing wounds indicated that compared to adjuvanted peptide assemblies, the unadjuvanted assemblies exhibited a progression of the dominant T-cell subset from CD4+ to CD8+ cells in the wound, and CD4+ cell populations displayed a more Th2-slanted response. These findings illustrate an example of a significant antibiomaterial adaptive immune response that does not adversely affect wound healing despite ongoing antibody production. This material would thus be considered 'immunologically compatible' in this specific context rather than 'nonimmunogenic,' a designation that is expected to apply to a range of other protein- and peptide-based biomaterials in wound-healing and tissue-engineering applications. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1853-1862, 2016. [ABSTRACT FROM AUTHOR]

Islet transplantation is currently in clinical use as a treatment for type I diabetes, but donor shortages and long-term immunosuppression limit broad application. Alginate microcapsules coated with poly- l-ornithine can be used to encapsulate islets in an environment that allows diffusion of glucose, insulin, nutrients, and waste products while inhibiting cells and antibodies. While clinical trials are ongoing using islets encapsulated in alginate microbeads, there are concerns in regards to long-term stability. Evaluation of the local tissue response following implantation provides insight into the underlying mechanisms contributing to biomaterial failure, which can be used to the design of new material strategies. Macrophages play an important role in driving the response. In this study, the stability of alginate microbeads coated with PLO containing islets transplanted in the omentum pouch model was investigated. Biomaterial structure and the inflammatory response were characterized by X-ray phase contrast (XPC) μCT imaging, histology, and immunostaining. XPC allowed evaluation of microbead 3D structure and identification of failed and stable microbeads. A robust inflammatory response characterized by high cell density and the presence of pro-inflammatory macrophages was found around the failed grafts. The results obtained provide insight into the local tissue response and possible failure mechanisms for alginate microbeads. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1581-1590, 2016. [ABSTRACT FROM AUTHOR]

The field of biomaterials science is highly active, with a steadily increasing number of publications and new journals being founded. This article brings together contributions from the editors of six leading journals in the area of biomaterials science and engineering. Each contributor highlights specific advances, topics, and trends that have emerged through the publications in their respective journal in the calendar year 2022. It presents a global perspective on a wide range of material types, functionalities, and applications. The highlighted topics include a diversity of biomaterials; from proteins, polysaccharides, and lipids to ceramics, metals, advanced composites, and a variety of new forms of these materials. Important advances in dynamically functional materials are presented, including a range of fabrication techniques such as bioassembly, 3D bioprinting and microgel formation. Similarly, several applications are highlighted in drug and gene delivery, biological sensing, cell guidance, immunoengineering, electroconductivity, wound healing, infection resistance, tissue engineering, and treatment of cancer. The goal of this paper is to provide the reader with both a broad view of recent biomaterials research, as well as expert commentary on some of the key advances that will shape the future of biomaterials science and engineering. [ABSTRACT FROM AUTHOR]

Despite the attractive combinations of cell/surface interactions, biocompatibility, and good mechanical properties of Ti‐6Al‐4V, there is still a need to enhance the early stages of cell/surface integration that are associated with the implantation of biomedical devices into the human body. This paper presents a novel, easy and reproducible method of nanoscale and nanostructured hydroxyapatite (HA) coatings on Ti‐6Al‐4V. The resulting nanoscale coatings/nanostructures are characterized using a combination of Raman spectroscopy, scanning electron microscopy equipped with energy dispersive x‐ray spectroscopy. The nanostructured/nanoscale coatings are shown to enhance the early stages of cell spreading and integration of bone cells (hFOB cells) on Ti‐6Al‐4V surfaces. The improvements include the acceleration of extra‐cellular matrix, cell spreading and proliferation by nanoscale HA structures on the coated surfaces. The implications of the results are discussed for the development of HA nanostructures for the improved osseointegration of Ti‐6Al‐4V in orthopedic and dental applications. [ABSTRACT FROM AUTHOR]

A severe disorder known as spinal cord damage causes both motor and sensory impairment in the limbs, significantly reducing the patients' quality of life. After a spinal cord injury, functional recovery and therapy have emerged as critical concerns. Hydrogel microspheres have garnered a lot of interest lately because of their enormous promise in the field of spinal cord injury rehabilitation. The material classification of hydrogel microspheres (natural and synthetic macromolecule polymers) and their synthesis methods are examined in this work. This work also covers the introduction of several kinds of hydrogel microspheres and their use as carriers in the realm of treating spinal cord injuries. Lastly, the study reviews the future prospects for hydrogel microspheres and highlights their limitations and problems. This paper can offer feasible ideas for researchers to advance the application of hydrogel microspheres in the field of spinal cord injury. [ABSTRACT FROM AUTHOR]

Cardiovascular disease (CVD) remains to be the leading cause of death globally today and therefore the need for the development of novel therapies has become increasingly important in the cardiovascular field. The mechanism(s) behind the pathophysiology of CVD have been laboriously investigated in both stem cell and bioengineering laboratories. Scientific breakthroughs have paved the way to better mimic cell types of interest in recent years, with the ability to generate any cell type from reprogrammed human pluripotent stem cells. Mimicking the native extracellular matrix using both organic and inorganic biomaterials has allowed full organs to be recapitulated in vitro. In this paper, we will review techniques from both stem cell biology and bioengineering which have been fruitfully combined and have fueled advances in the cardiovascular disease field. We will provide a brief introduction to CVD, reviewing some of the recent studies as related to the role of endothelial cells and endothelial cell dysfunction. Recent advances and the techniques widely used in both bioengineering and stem cell biology will be discussed, providing a broad overview of the collaboration between these two fields and their overall impact on tissue engineering in the cardiovascular devices and implications for treatment of cardiovascular disease. [ABSTRACT FROM AUTHOR]

Acellular porcine cornea (APC) has been used in corneal transplantation and treatment of the corneal diseases. Sterilization is a key step before the application of graft, and irradiation is one of the most commonly used methods. In this paper, APC was prepared by the physical freeze‐thawing combined with biological enzymes, and the effects of the electron beam (E‐beam) and cobalt 60 (60Co‐γ) at the dose of 15 kGy on the physicochemical properties, structure, immunogenicity, and biocompatibility of the APC were investigated. After decellularization, the residual DNA was 20.86 ± 1.02 ng/mg, and the α‐Gal clearance rate was more than 99%. Irradiation, especially the 60Co‐γ, reduced the cornea's transmittance, elastic modulus, enzymatic hydrolysis rate, swelling ratio, and cross‐linking degree. Meanwhile, the diameter and spacing of the collagen fibers increased. In the rat subcutaneous implantation, many inflammatory cells appeared in the unirradiated APC, while the irradiated had good histocompatibility, but the degradation was faster. The lamellar keratoplasty in rabbits indicated that compared to the E‐beam, the 60Co‐γ damaged the chemical bond of collagen to a larger extent, reduced the content of GAGs, and prolonged the complete epithelization of the grafts. The corneal edema was more serious within 1 month after the surgery. After 2 months, the thickness of the APC with the two irradiation methods tended to be stable, but that in the 60Co‐γ group became thinner. The pathological results showed that the collagen structure was looser and the pores were larger, indicating the 60Co‐γ had a more extensive effect on the APC than the E‐beam at 15 kGy. [ABSTRACT FROM AUTHOR]

In the past decade, three‐dimensional (3D) printing technology based on digital light processing (DLP) has developed rapidly and shown application prospects in several fields such as pneumatic robotics, flexible electronics, and tissue engineering. In particular, DLP‐based multi‐material printing has been capable of constructing heterogeneous 3D structures with characteristic gradients. DLP 3D printing technology has a wide range of applications in the field of bioprinting due to its high precision and mild printing conditions, including functionalized artificial tissues, medical models, and bioreactors. This paper focuses on the development of DLP‐based multi‐material 3D printing technology and its applications in the field of bioprinting, followed by giving an outlook on future efforts on overcoming the challenges and obstacles of this promising technique. [ABSTRACT FROM AUTHOR]

Bone marrow mesenchymal stem cell sheet‐derived spheroids (BMSCs spheroids) have been widely studied as native bioactive scaffolds. However, the abundant cells in BMSCs spheroids cause immunogenicity and make them difficult to store. This paper aimed to construct a new bioactive scaffold called 3D‐decellularized extracellular matrix spheroids (ECM spheroids) via decellularization of BMSCs spheroids to enhance bone formation. Hematoxylin and eosin staining (HE), nuclear and cytoskeletal fluorescence, immunofluorescence (IF), and scanning electron microscopy (SEM) were utilized to detect the characteristics and components of ECM spheroids. Furthermore, the biological properties of migration, adhesion, and recellularization of cells in ECM spheroids were assessed in vitro, and bone formation was evaluated in rat calvarial defects. The results showed that both the nuclei and cytoskeleton in ECM spheroids were greatly altered and one of the major components of FN was intact. The migration, adhesion, and recellularization potential were improved in vitro. Meanwhile, ECM spheroids promoted osteogenesis in rat skull defects after 3 months (p <.01). In conclusion, ECM spheroids were successfully prepared and proven to promote cell migration, adhesion, and proliferation. Bone formation in vivo was also accelerated. We believe that ECM spheroids can be used as bioactive and biocompatible 3D scaffolds in the future. [ABSTRACT FROM AUTHOR]

MXene, as a new two‐dimensional nanomaterial, is endowed with lots of particular properties, such as large surface area, excellent conductivity, biocompatibility, biodegradability, hydrophilicity, antibacterial activity, and so on. In the past few years, MXene nanomaterials have become a rising star in biomedical fields including biological imaging, tumor diagnosis, biosensor, and tissue engineering. In this review, we sum up the recent applications of MXene nanomaterials in the field of tissue engineering and regeneration. First, we briefly introduced the synthesis and surface modification engineering of MXene. Then we focused on the application and development of MXene and MXene‐based composites in skin, bone, nerve and heart tissue engineering. Uniquely, we also paid attention to some research on MXene with few achievements at present but might become a new trend in tissue engineering and regeneration in the future. Finally, this paper will also discuss several challenges faced by MXene nanomaterials in the clinical application of tissue engineering. [ABSTRACT FROM AUTHOR]

Abstract: Articular cartilage (AC) has gradient features in both mechanics and histology as well as a poor regeneration ability. The repair of AC poses difficulties in both research and the clinic. In this paper, a gradient scaffold based on poly(lactic‐co‐glycolic acid) (PLGA)‐extracellular matrix was proposed. Cartilage scaffolds with a three‐layer gradient structure were fabricated by PLGA through three‐dimensional printing, and the microstructure orientation and pore fabrication were made by decellularized extracellular matrix injection and directional freezing. The manufactured scaffold has a mechanical strength close to that of real cartilage. A quantitative optimization of the Young's modulus and shear modulus was achieved by material mechanics formulas, which achieved a more accurate mechanical bionic and a more stable interface performance because of the one‐time molding process. At the same time, the scaffolds have a bionic and gradient microstructure orientation and pore size, and the stratification ratio can be quantitatively optimized by design of the freeze box and temperature simulation. In general, this paper provides a method to optimize AC scaffolds by both mechanics and histology as well as a bionic multimaterial scaffold. This paper is of significance for cell culture and clinical transplantation experiments. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1664–1676, 2018. [ABSTRACT FROM AUTHOR]

Over the last two decades, electrospun scaffolds have proved to be advantageous in the field of nerve tissue regeneration by connecting the cavity among the proximal and distal nerve stumps growth cones and leading to functional recovery after injury. Multifunctional nanofibrous structure of these scaffolds provides enormous potential by combining the advantages of nano‐scale topography, and biological science. In these structures, selecting the appropriate materials, designing an optimized structure, modifying the surface to enhance biological functions and neurotrophic factors loading, and native cell‐like stem cells should be considered as the essential factors. In this systematic review paper, the fabrication methods for the preparation of aligned nanofibrous scaffolds in yarn or conduit architecture are reviewed. Subsequently, the utilized polymeric materials, including natural, synthetic and blend are presented. Finally, their surface modification techniques, as well as, the recent advances and outcomes of the scaffolds, both in vitro and in vivo, are reviewed and discussed. [ABSTRACT FROM AUTHOR]

The global market for dental materials is predicted to exceed 10 billion dollars by 2020. The main drivers for this growth are easing the workflow of dentists and increasing the comfort of patients. Therefore, remarkable research projects have been conducted and are currently underway to develop improved or new dental materials with enhanced properties or that can be processed using advanced technologies, such as CAD/CAM or 3D printing. Among these materials, zirconia, glass or polymer-infiltrated ceramics, and glass-ceramics (GCs) are of great importance. Dental glass-ceramics are highly attractive because they are easy to process and have outstanding esthetics, translucency, low thermal conductivity, high strength, chemical durability, biocompatibility, wear resistance, and hardness similar to that of natural teeth, and, in certain cases, these materials are bioactive. In this review article, we divide dental GCs into the following two groups: restorative and bioactive. Most restorative dental glass-ceramics (RDGCs) are inert and biocompatible and are used in the restoration and reconstruction of teeth. Bioactive dental glass-ceramics (BDGCs) display bone-bonding ability and stimulate positive biological reactions at the material/tissue interface. BDGCs are suggested for dentin hypersensitivity treatment, implant coating, bone regeneration and periodontal therapy. Throughout this paper, we elaborate on the history, processing, properties and applications of RDGCs and BDGCs. We also report on selected papers that address promising types of dental glass-ceramics. Finally, we include trends and guidance on relevant open issues and research possibilities. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 619-639, 2017. [ABSTRACT FROM AUTHOR]

Biodegradable magnesium‐based implants are the subject of a great deal of research for different orthopedic and vascular applications. The targeted design and properties depend on the specific medical function and location in the body. Development of the biomaterial requires a comprehensive understanding of the biological interaction between the implant and the host tissue, as well as of the behavior in the physiological environment in vivo. Research into and the development of innovative magnesium implants entails interdisciplinary research efforts and communication between materials science, bioscience, and medical experts. The present study provides a transparent planning and communication tool for market‐oriented implant development processes. The objective was to identify medical needs at an early stage of the development process and to quantify the importance of the engineering characteristics of different research fields that cater to specific implant requirements. The method is demonstrated by the performance of a survey‐based conjoint analysis, which was integrated into a quality function deployment approach. Twenty‐seven medical professionals and 29 biomaterial scientists assessed the importance of identified medical requirements, whereby the control of mechanical integrity and degradation along with nontoxicity and nonimmunogenicity showed the highest number of preferences. The evaluation of implant options by 31 experts indicated that the engineering characteristic with the highest importance was the condition and sterilization of the surface. These values can be used to set priorities in strategic decisions. Research trials can be aligned to medical preferences, ensuring high product quality and an effective development process. This is the first paper to report on the application of conjoint‐based quality function deployment in biomaterial research. [ABSTRACT FROM AUTHOR]

Abstract: Measurement of the mechanical properties of skin in vivo has been complicated by the lack of methods that can accurately measure the viscoelastic properties without assuming values of Poisson's ratio and tissue density. In this paper, we present the results of preliminary studies comparing the mechanical properties of skin and scar tissue measured using a technique involving optical cohesion tomography (OCT) and vibrational analysis. This technique has been reported to give values of the modulus that correlate with those obtained from tensile measurements made on decellularized dermis (Shah et al., Skin Res Technol 2016;23:399–406; Shah et al., J Biomed Mater Res Part 2017;105:15–22). The high correlation between moduli measured using vibrational studies and uniaxial tensile tests suggest that the modulus can be determined by measuring the natural frequency that occurs when a tissue is vibrated in tension. The results of studies on glutaric anhydride treated decellularized dermis suggest that vibrational analysis is a useful technique to look at changes in the properties of skin that occur after cosmetic and surgical treatments are used. Preliminary results suggest that the resonant frequency of scar tissue is much higher than that of adjacent normal skin reflecting the higher collagen content of scar. OCT in concert with vibrational analysis appears to be a useful tool to evaluate processes that alter skin properties in animals and humans as well to study the onset and pathogenesis of skin diseases such as cancer. This technique may be useful to evaluate the extent of wound healing in skin diabetic ulcers and other chronic skin conditions, scar tissue formation in response to implants, and other therapeutic treatments that alter skin properties. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1421–1427, 2018. [ABSTRACT FROM AUTHOR]

The demand of new strategies for the induction of bone regeneration is continuously increasing. Biomimetic porous gelatin-nanocrystalline hydroxyapatite scaffolds with tailored properties were previously developed, showing a positive response in terms of cell adhesion, proliferation, and differentiation. In the present paper, we focused on their osteoinductive properties. The effect of scaffolds on osteogenic differentiation of human mesenchymal stromal cells (hMSCs) was investigated in vitro. hMSCs were seeded on GEL (type A gelatin) and GEL containing 10 wt% hydroxyapatite (GEL-HA) and cultured in osteogenic medium. Results showed that GEL and GEL-HA10 sustained hMSC differentiation, with an increased ALP activity and a higher expression of bone specific genes. The osteoinductive ability of these scaffolds was then studied in vivo in a heterotopic bone formation model in nude mice. The influence of hMSCs within the implants was examined as well. Both GEL and GEL-HA10 scaffolds mineralized when implanted without hMSCs. On the contrary, the presence of hMSC abolished or reduced mineralization of GEL and GEL-HA10 scaffolds. However, we could observe a species-specific response to the presence of HA, which stimulated osteogenic differentiation of human cells only. In conclusion, the scaffolds showed promising osteoinductive properties and may be suitable for use in confined critical defects. [ABSTRACT FROM AUTHOR]

The use of biomaterial scaffolds has been an enormous field of research in tissue engineering, where the aim is to use graft materials for assisting the human body in recovering lost functions. Currently, there are many ways biomaterial scaffolds can be fabricated; however, many of these techniques involve the use of toxic organic solvents during the process. As biocompatibility is one of the mandatory requirements in designing a successful scaffold, there is an interest in fabricating scaffolds that are completely organic solvent-free. This paper describes the development and characterization of novel micro-/nano-fibrillar composites (MFC/NFC) that can produce scaffolds which are completely free from organic solvents. In this research, the cytocompatibility of these materials have been tested in vitro using mouse osteoblast-like cells and primary rat tenocytes, where cell numbers increase over the culture period, demonstrating the material viability. Gene expression analysis of primary rat tenocytes on MFC/NFC scaffolds demonstrate tenocytic behavior, and histology studies show an increase in cell formation on NFC scaffolds. This study establishes the potential of using the MFC/NFC technique to produce completely organic solvent-free scaffolds capable of hosting musculoskeletal cells, in the hope of providing a graft material for non-union skeletal fractures and rotator cuff repairs. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1393-1404, 2017. [ABSTRACT FROM AUTHOR]

This study aimed to systematically review the literature of animal studies to evaluate whether bioactive dentin proteins could improve vital pulp therapy success. The review is reported in accordance with the PRISMA Statement. Two reviewers independently conducted a literature search of seven databases: PubMed (Medline), Lilacs, IBECS, BBO, Web of Science, Scopus, and SciELO. Animal experiments in which bioactive dentin proteins were applied directly or indirectly to the pulp tissue were included. Data regarding the characteristics of the proteins evaluated, the delivery systems used and the main findings from each study were tabulated to assess the outcomes of interest (tertiary dentin formation, inflammatory response, intratubular mineralization). After screening, 32 papers were subjected to qualitative analysis. In 75% of the studies, direct pulp capping was performed. Additionally, the most studied proteins were BMP-7, TGF-β1, and extracted soluble dentin matrix proteins. In conclusion, there is evidence in the literature suggesting that bioactive dentin molecules could enhance tertiary dentin formation with fewer initial inflammatory responses in direct and indirect pulp therapy in animal models. There are potential areas to be explored for novel therapeutic approaches for dental tissue repair and regeneration with bioactive materials. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 941-956, 2017. [ABSTRACT FROM AUTHOR]

In this paper, autofluorescent gelatin nanoparticles were synthesized as matrix metalloproteinase (MMP) responsive probes for cancer cell imaging. A modified two-step desolvation method was employed to generate these nanoparticles whose size was controllable and had stable autofluorescence. As glutaraldehyde was introduced as the crosslinking agent, the generation of Schiff base (CN) and double carbon bond (CC) between glutaraldehyde and gelatin endowed these gelatin nanoparticles distinct autofluorescence. Considering MMPs were usually overexpressed on the surface of cancer cells and they had degradation ability toward gelatin, we utilized these nanoparticles as imaging probes to responsively monitor the MMP metabolism of cancer cells according to the luminance change. As fluorescent probes, these nanoparticles had facile synthesis procedure and good biocompatibility, and provided a smart strategy to monitor cancer cell behaviors. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2854-2860, 2016. [ABSTRACT FROM AUTHOR]

Hemocompatibility evaluation of biomaterials necessitates the use of blood incubation systems which simulate physiological flow conditions. However, most of the current systems have various limitations, especially restricted material variability, poor access to the test surface or damage of blood cells due to the use of a pump. In this paper, we combined the advantages of existent setups and developed a new planar shaped incubation test bench to lift those restrictions and mimic the pulsatile in-vivo situation. The adjustable flow conditions at the tested material surface were defined and corresponded to those in blood vessels. Platelet/material-interaction, as major aspect of hemocompatibility, was investigated for four common polymeric materials (polyoxymethylene, polypropylene, polyethylene and silicone elastomer) with platelet deprivation and platelet adhesion tests. Highly significant differences in the adhesion of platelets onto the tested material surfaces were measured. The number of adhered platelets on the most hydrophobic sample (silicone elastomer) was four-times higher than on the most hydrophilic sample (polyoxymethylene). These findings were confirmed with a scanning microscopic analysis and demonstrated the suitability of the testing device for the evaluation of platelet/material interactions. Moreover, hemolysis measurements demonstrated that the system did not provoke blood damage. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2430-2440, 2016. [ABSTRACT FROM AUTHOR]

Numerous studies have shown that surface topography can promote cell-substrate associations and deeply influence cell fate. The intracellular mechanism or how micro- or nano-patterned extracellular signal is ultimately linked to activity of nuclear transcription factors remains unknown. It has been reported that Yes-associated protein (YAP) can respond to extracellular matrix microenvironment signals, thus regulates stem cell differentiation process. We propose that YAP may play a role in mediating the topography induced cell differentiation. To this end, we fabricated polydimethylsiloxane (PDMS) micropatterns with grid topology (GT) (3 μm pattern width, 2 μm pattern interval length, 7 μm pattern height); nonpatterned PDMS substrates were used as the planar controls. The MC3T3-E1 cells were then cultured on these surfaces, respectively, in osteogenic inducing medium. Cell differentiation in terms of osteogenesis related gene expression, protein levels, alkaline phosphatase activity and extracellular matrix mineralization was assessed. It was shown that the cells on GT surfaces had stronger osteogenesis capacity. In addition, expression level of YAP was increased when MC3T3-E1 cells grew on GT substrates, which was similar to the levels of osteogenic differentiation markers. It was also shown that YAP knockdown attenuated GT substrates-induced MC3T3-E1 differentiation, which reduced the osteogenic differentiation effect of the GT substrates. Collectively, our findings indicate that GT substrates-induced MC3T3-E1 differentiation may be associated with YAP. This paper provides new target points for transcriptional mechanism research of microenvironment induced cell differentiation and a useful approach to obtain more biofunctionalization scaffolds for tissue engineering. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1143-1152, 2016. [ABSTRACT FROM AUTHOR]

Stainless steel 316 L material is commonly used for the production of coronary and peripheral vessel stents. Effective biofunctionalization is a key to improving the performance and safety of the stents after implantation. This paper reports the method for the immobilization of recombinant antibody fragments (scFv) on stainless steel 316 L to facilitate human endothelial progenitor cell (EPC) growth and thus improve cell viability of the implanted stents for cardiovascular applications. The modification of stent surface was conducted in three steps. First the stent surface was coated with titania based coating to increase the density of hydroxyl groups for successful silanization. Then silanization with 3 aminopropyltriethoxysilane (APTS) was performed to provide the surface with amine groups which presence was verified using FTIR, XPS, and fluorescence microscopy. The maximum density of amine groups (4.8*10−5 mol/cm2) on the surface was reached after reaction taking place in ethanol for 1 h at 60° C and 0.04 M APTS. On such prepared surface the glycosylated scFv were subsequently successfully immobilized. The influence of oxidation of scFv glycan moieties and the temperature on scFv coating were investigated. The fluorescence and confocal microscopy study indicated that the densest and most uniformly coated surface with scFv was obtained at 37°C after oxidation of glycan chain. The results demonstrate that the scFv cannot be efficiently immobilized without prior aminosilanization of the surface. The effect of the chemical modification on the cell viability of EPC line 55.1 (HucPEC-55.1) was performed indicating that the modifications to the 316 L stainless steel are non-toxic to EPCs. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 821-832, 2016. [ABSTRACT FROM AUTHOR]

Due to their unique size and properties, nanomaterials have numerous applications, which range from electronics, cosmetics, household appliances, energy storage, and semiconductor devices, to medical products such as biological sensors, drug carriers, bioprobes, and implants. Many of the promising properties of nanomaterials arise from their large surface to volume ratio and, therefore, nanobiomaterials that are implantable have a large contact area with the human body. Before, therefore, we can fully exploit nanomaterials, in medicine and bioengineering; it is necessary to understand how they can affect the human body. As a step in this direction, this review paper provides a comprehensive summary of the effects that the physicochemical properties of commonly used nanobiomaterials have on their toxicity. Furthermore, the possible mechanisms of toxicity are described with the aim to provide guidance concerning the design of the nanobiomaterials with desirable properties. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103: 2499-2507, 2015. [ABSTRACT FROM AUTHOR]

Although a number of tissue adhesives and sealants for surgical use are currently available, attaining a useful balance in high strength, high compliance, and low swelling has proven difficult. Recent studies have demonstrated that a four-arm poly(propylene oxide)-poly(ethylene oxide) block copolymer, Tetronic, can be chemically modified to form a hydrogel tissue adhesive (Cho et al., Acta Biomater 2012;8:2223-2232; Barrett et al., Adv Health Mater 2012;1-11; Balakrishnan, Evaluating mechanical performance of hydrogel-based adhesives for soft tissue applications. Clemson University, All Theses, Paper 1574: Tiger Prints; 2013). Building on the success of these studies, this study explored bifunctionalization of Tetronic with acrylates for chemical crosslinking of the hydrogel and N-hydroxysuccinimide (NHS) for reaction with tissue amines. The adhesive bond strengths of various uni and bifunctional Tetronic blends (T1107 ACR: T1107 ACR/NHS) determined by lap shear testing ranged between 8 and 74 kPa, with the 75:25 (T1107 ACR: T1107 ACR/NHS) blend displaying the highest value. These results indicated that addition of NHS led to improvement of tissue bond strength over acrylation alone. Furthermore, ex vivo pressure tests using the rat bladder demonstrated that the bifunctional Tetronic adhesive exhibited high compliance and maintained pressures under hundreds of filling and emptying cycles. Together, the results of this study provided evidence that the bifunctional Tetronic adhesive with a proper blend ratio may be used to achieve an accurate balance in bulk and tissue bond strengths, as well as the compliance and durability for soft tissue such as the bladder. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 861-868, 2015. [ABSTRACT FROM AUTHOR]

Poly( d, l-lactide- co-glycolide) (PLGA) is widely used in a variety of tissue engineering and drug delivery applications due to its biodegradability and biocompatibility. But PLGA surfaces are usually hydrophobic which limited the loading and seeding capacities for cells, especially semiadherent immune cells. In this paper we described an attempt to improve the hydrophilicity and surface architecture for accommodating dendritic cells (DCs) that are widely used as professional antigen presenting cells in immune therapy of cancer and other diseases. The 3D porous PLGA scaffold was made by solvent casting/salt leaching of PLGA blended with surface functionalized multiwalled carbon nanotubes (F-MWCNTs). The incorporation and dispersion of F-MWCNT in the scaffold structures resulted in not only improved surface hydrophilicity but also nanoscale surface structure that would provide a preferable microenvironment for DCs attachment. We think such a scaffold material may be more desirable for immune cell delivery for immunotherapy. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 1045-1052, 2015. [ABSTRACT FROM AUTHOR]

Viruses are no longer recognized purely for being ubiquitous pathogens, but have served as building blocks for material chemistry and nanotechnology. Thousands of coat protein subunits of a viral particle can be modified chemically and/or genetically. We have previously shown that the three-dimensional porous hydrogels can easily be functionalized by Tobacco mosaic virus (TMV), a rod-like plant virus, using its mutant, RGD-TMV. RGD-TMV hosted bioadhesive peptide (RGD) in the hydrogel, which was shown to enhance cell attachment and promote osteogenic differentiation of cultured stem cell. To translate this technology to potential clinical applications, we sought to study the biocompatibility of the hydrogel. In this paper, the hydrogels were implanted in vivo and assessed for their immunogenicity, toxicity, and biodegradability. Immune response for TMV substantially decreased when incorporated in the hydrogel implants. The implanted TMV hydrogels exhibited no apparent toxicity and were degradable in mice. The results highlighted the feasibility of using TMV incorporated hydrogels as scaffolding materials for regenerative medicine in terms of biocompatibility and biodegradability. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 887-895, 2015. [ABSTRACT FROM AUTHOR]

Osseointegration is important when implants are inserted into the bone and can be improved by biochemical surface coating of the implant. In this paper enzymatically modified rhamnogalacturonan I (RG-I) from apple and lupin was used for biochemical coating of aminated surfaces and the importance of the quality of RG-I, the nature of the binding, the fine structure of RG-I, and its effect on SaOS-2 cell line cultured on coated surfaces was investigated. SaOS-2 cells are osteoblast-like cells and a well-established in vitro model of bone-matrix forming osteoblasts. Purification by gel filtration could remove small fragments of galacturonic acid (GalA) and binding studies showed that the purity of the RG-I molecules was important for the quality of the coating. The structure of RG-I and osteoblast-like cells' viability were positively correlated so that high content of 1,4-linked galactose (Gal) and a low content of arabinose in the RG-I molecules favored cell viability. These results indicate that coating of implants with RG-I affect osseointegration positively. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 1961-1971, 2014. [ABSTRACT FROM AUTHOR]

Great deal of research is still going on in the field of orthopedic and craniofacial implant development to resolve various issues being faced by the industry today. Despite several disadvantages of the metallic implants, they continue to be used, primarily because of their superior mechanical properties. In order to minimize the harmful effects of the metallic implants and its by-products, several modifications are being made to these materials, for instance nickel-free stainless steel, cobalt-chromium and titanium alloys are being introduced to eliminate the toxic effects of nickel being released from the alloys, introduce metallic implants with lower modulus, reduce the cost of these alloys by replacing rare elements with less expensive elements etc. New alloys like tantalum, niobium, zirconium, and magnesium are receiving attention given their satisfying mechanical and biological properties. Non-oxide ceramics like silicon nitride and silicon carbide are being currently developed as a promising implant material possessing a combination of properties such as good wear and corrosion resistance, increased ductility, good fracture and creep resistance, and relatively high hardness in comparison to alumina. Polymer/magnesium composites are being developed to improve mechanical properties as well as retain polymer's property of degradation. Recent advances in orthobiologics are proving interesting as well. This paper thus deals with the latest improvements being made to the existing implant materials and includes new materials being introduced in the field of biomaterials. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 3349-3364, 2013. [ABSTRACT FROM AUTHOR]

This paper describes the discovery of the first inhibitors of angiogenesis; the discoveries that led to the development of the first biocompatible controlled release systems for macromolecules, and findings that helped to create the field of tissue engineering. In addition, new paradigms for creating biomaterials, early work on nanotechnology in medicine and intelligent drug delivery systems are discussed. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 2449-2455, 2013. [ABSTRACT FROM AUTHOR]

Interactions between biomolecules and inorganic surfaces play an important role in natural environments and in industry, including a wide variety of conditions: marine environment, ship hulls (fouling), water treatment, heat exchange, membrane separation, soils, mineral particles at the earth's surface, hospitals (hygiene), art and buildings (degradation and biocorrosion), paper industry (fouling) and more. To better control the first steps leading to adsorption of a biomolecule on an inorganic surface, it is mandatory to understand the adsorption mechanisms of biomolecules of several sizes at the atomic scale, that is, the nature of the chemical interaction between the biomolecule and the surface and the resulting biomolecule conformations once adsorbed at the surface. This remains a challenging and unsolved problem. Here, we review the state of art in experimental and theoretical approaches. We focus on metallic biomaterial surfaces such as TiO2 and stainless steel, mentioning some remarkable results on hydroxyapatite. Experimental techniques include atomic force microscopy, surface plasmon resonance, quartz crystal microbalance, X-ray photoelectron spectroscopy, fluorescence microscopy, polarization modulation infrared reflection absorption spectroscopy, sum frequency generation and time of flight secondary ion mass spectroscopy. Theoretical models range from detailed quantum mechanical representations to classical forcefield-based approaches. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013. [ABSTRACT FROM AUTHOR]

This paper proposes a novel biodegradable nerve conduit comprising 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) cross-linked gelatin, annexed with β-tricalcium phosphate (TCP) ceramic particles (EDC-Gelatin-TCP, EGT). In this study, the EGT-implant site in rats was irradiated using a large-area 660 nm AlGaInP diode laser (50 mW) to investigate the feasibility of laser stimulation in the regeneration of a 15-mm transected sciatic nerve. The animals were divided into three groups: a sham-irradiated group (EGT/sham); an experimental group undergoing low-level laser (LLL) therapy (EGT/laser); a control group undergoing autologous nerve grafts (autografts). Twelve weeks after implantation, walking track analysis showed a significantly higher sciatic functional index ( p < 0.05) and improved toe spreading development in the EGT/laser and autograft groups than in the EGT/sham group. In electrophysiological measurement, both the mean peak amplitude and the area under the compound muscle action potential curves in the EGT/laser and autograft groups showed significantly improved functional recovery than the EGT/sham group ( p < 0.05). Compared with the EGT/sham group, the EGT/laser and autograft groups displayed a reduction in muscular atrophy. Histomorphometric assessments revealed that the EGT/laser group had undergone more rapid nerve regeneration than the EGT/sham group. The laser-treated group also presented greater neural tissue area as well as larger axon diameter and thicker myelin sheath than the tube group without the laser treatment, indicating improved nerve regeneration. Thus, these assessments demonstrate that LLL therapy can accelerate the repair of a transected peripheral nerve in rats after being bridged with EGT conduit. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A:239-252, 2013. [ABSTRACT FROM AUTHOR]

This paper is concerned with reliable and physically sound elasticity determination of rapid-prototyped tissue engineering scaffolds made of poly- L-lactide (PLLA), with and without small portions of tricalcium phosphate (TCP) inclusions. At the level of overall scaffolds, that is, that of several millimeters, multiple uniaxial loading-unloading (quasistatic) tests were performed, giving access to the scaffolds' Young's moduli, through stress-strain characteristics during unloading. In addition, acoustic tests with 0.05 MHz frequency delivered an independent access to elastic properties, in terms of the normal components of the scaffolds' stiffness tensors. The latter strongly correlate, in a linear fashion, with the Young's moduli from the unloading tests, revealing porosity independence of Poisson's ratio. The magnitude of the latter is in full agreement with literature data on polymers. Both of these facts underline that both ultrasound tests and quasistatic unloading tests reliably provide the elastic properties of tissue engineering scaffolds. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A:138-144, 2013. [ABSTRACT FROM AUTHOR]

This paper reports the electrospinning of a series of oxidatively stable polycarbonate urethanes (PCU) [carbothane (ECT), bionate (EBN), and chronoflex (ECF)] using N, N-dimethyl formamide and tetrahydrofuran as the mixed solvent. The nonwoven membranes were characterized for their structure, performance, and compatibility with cells. Scanning electron microscope was utilized to study the structural morphology and fiber diameter. Microcomputed tomography (micro-CT) was used to characterize the 3D architecture, pore size distribution, and percentage porosity. All the membranes displayed a porous architecture with average fiber diameter in the range of 1.5-2 μm. Static mechanical tests on the membranes revealed that the tensile strength was greater than 7 MPa and the dynamic mechanical tests showed that the average storage modulus ( E i) is 2 MPa at 37°C. PCU membranes were subjected to accelerated in vitro degradation for 90 days in 20% hydrogen peroxide/0.1 M cobalt chloride solution. Mechanical characterization of the membranes postdegradation confirmed a 64% reduction in tensile strength for EBN at the end of 90 days where as ECF and ECT did not show any significant mechanical property deterioration in the oxidative medium. Cytotoxicity of the membranes was evaluated using L929 fibroblast cells and the results indicated that all the PCU membranes were cytocompatible and showed good adherence to L929 cells. Accordingly, these results highlight the potential of these fibrous PCU membranes for biomedical applications but further in vivo correlation studies are required for better understanding of the biodegradation and biological efficacy. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:3042-3050, 2012. [ABSTRACT FROM AUTHOR]

Polyetheretherketone (PEEK) is a promising material for use in orthopedic implants, but its bio‐inert character and lack of antibacterial activity limit its applications in bone repair. In the present study, considering the advantages of PEEK in self‐initiated graft polymerization and of hydrogels in bone tissue engineering, we constructed a hydrogel coating (GPL) consisting of Gelatin methacryloyl (GelMA), methacrylamide‐modified ε‐poly‐l‐lysine (ε‐PLMA) and Laponite on PEEK through UV‐initiated crosslinking. The coating improved the hydrophilicity of PEEK, and the coating degraded slowly so that approximately 80% was retained after incubation in PBS for 8 weeks. In vitro studies revealed that as compared to culturing on PEEK, culturing on PEEK‐GPL led to enhanced viability and adhesion of cultured human umbilical cord Wharton's jelly‐derived mesenchymal stem cells (hWJ‐MSCs). Due to the synergistic effect of the micron‐scale three‐dimensional surface and Laponite, PEEK‐GPL exhibited a significantly improved induction of osteogenic differentiation of hWJ‐MSCs compared to PEEK, as demonstrated by increased alkaline phosphatase activity, matrix mineralization, and expression of osteogenesis‐related genes. Furthermore, PEEK‐GPL showed antibacterial activity upon contact with Staphylococcus aureus and Escherichia coli, and this activity would be maintained before complete degradation of the hydrogel because the ε‐PLMA was cross‐linked covalently into the coating. Thus, PEEK‐GPL achieved both osteogenesis and infection prevention in a single simple step, providing a feasible approach for the extensive use of PEEK in bone implants. [ABSTRACT FROM AUTHOR]

In this work, composite electrospun fibers containing innovative bioactive glass nanoparticles were produced and characterized. Poly(ε‐caprolactone), benign solvents, and sol–gel B‐ and Cu‐doped bioactive glass powders were used to fabricate fibrous scaffolds. The retention of bioactive glass nanoparticles in the polymer matrix, the electrospinnability of this novel solution and the obtained electrospun composites were extensively characterized. As a result, composite electrospun fibers characterized by biocompatibility, bioactivity, and exhibiting overall properties adequate for both hard and soft tissue engineering applications, have been produced. The addition of these bioactive glass nanoparticles was, indeed, able to impart bioactive properties to the fibers. Cell culture studies show promising results, demonstrating proliferation and growth of cells on the composite fibers. Wettability, degradation rate, and mechanical performance were also tested and are in line with previous results. [ABSTRACT FROM AUTHOR]

Poly(glycerol sebacate) (PGS) is an excellent scaffold material in tissue engineering due to good biocompatibility and tunable mechanical properties. The degradation properties of PGS have been primarily explored in static phosphate buffer solution or enzyme solution. It is vital to understand how the tensile stress affect the degradation rate. In this study, PGS was synthetized by melt polycondensation and its properties were characterized. Then an in vitro degradation device which could provide different constant tensile stresses was carefully designed and established, and the enzymatic degradation of PGS was tested under 0–150 kPa at 37°C. It was found that holes of PGS surface arranged almost parallel to each other and perpendicular to the direction of tensile stresses at 100 kPa and 150 kPa after 2–4 days degradation. After 8 days degradation, the ultimate tensile strength (UTS) of PGS at 150 kPa was 0.28 MPa and the elastic modulus was 1.11 MPa, while the UTS of PGS was 0.44 MPa and the elastic modulus was 1.63 MPa before degradation, both of them have significant differences. Hence, the tensile stress and degradation time were proportional to the appear time and size of holes, leading to the decrease of mass loss, UTS and elastic modulus. The relationship between stress and PGS degradation rates was quantitatively described through our degradation experiments, providing guidance for suitable PGS applications in the future. [ABSTRACT FROM AUTHOR]

Granular hydrogels are a promising biomaterial for a wide range of biomedical applications, including tissue regeneration, drug/cell delivery, and 3D printing. These granular hydrogels are created by assembling microgels through the jamming process. However, current methods for interconnecting the microgels often limit their use due to the reliance on postprocessing for crosslinking through photoinitiated reactions or enzymatic catalysis. To address this limitation, we incorporated a thiol‐functionalized thermo‐responsive polymer into oxidized hyaluronic acid microgel assemblies. The rapid exchange rate of thiol‐aldehyde dynamic covalent bonds allows the microgel assembly to be shear‐thinning and self‐healing, with the phase transition behavior of the thermo‐responsive polymer serving as secondary crosslinking to stabilize the granular hydrogels network at body temperature. This two‐stage crosslinking system provides excellent injectability and shape stability, while maintaining mechanical integrity. In addition, the aldehyde groups of the microgels act as covalent binding sites for sustained drug release. These granular hydrogels can be used as scaffolds for cell delivery and encapsulation, and can be 3D printed without the need for post‐printing processing to maintain mechanical stability. Overall, our work introduces thermo‐responsive granular hydrogels with promising potential for various biomedical applications. [ABSTRACT FROM AUTHOR]

Retrieval studies in the past two decades show severe corrosion of titanium and its alloys in orthopedic implants. This damage is promoted by mechanically assisted crevice corrosion (MACC), particularly within modular titanium‐titanium junctions. During MACC, titanium interfaces may be subject to negative potentials and reactive oxygen species (ROS), generated from cathodic activation and/or inflammation. Additive manufacturing (AM) may be able to produce new, corrosion‐resistant titanium alloys and admixtures that are less susceptible to these adverse electrochemical events. In this study, we characterize the impedance and corrosion properties of three new AM titanium materials, including Ti‐6Al‐4V with added 1% nano‐yttria stabilized ZrO2, admixed Ti‐29Nb‐21Zr, and pre‐alloyed Ti‐29Nb‐21Zr. We aim to elucidate how these materials perform when subjected to high ROS solutions. We include conventionally and additively manufactured Ti‐6Al‐4V in our study as comparison groups. A 0.1 M H2O2 phosphate‐buffered saline (PBS) solution, simulating inflammatory conditions, significantly increased biomaterial OCP (−0.14 V vs. Ag/AgCl) compared to PBS only (−0.38 V, p =.000). During anodic polarization, Ti‐6Al‐4V passive current density more than doubled from 1.28 × 10−7 to 3.81 × 10−7 A/cm2 when exposed to 0.1 M H2O2. In contrast, Ti‐29Nb‐21Zr passive current density remained relatively unchanged, slightly increasing from 7.49 × 10−8 in PBS to 9.31 × 10−8 in 0.1 M H2O2. Ti‐29Nb‐21Zr oxide polarization resistance (Rp) was not affected by 0.1 M H2O2, maintaining a high value (1.09 × 106 vs. 1.89 × 106 Ω cm2), while Ti‐6Al‐4V in 0.1 M H2O2 solution had significantly diminished Rp (4.38 × 106 in PBS vs. 7.24 × 104 Ω cm2 in H2O2). These results indicate that Ti‐29Nb‐21Zr has improved corrosion resistance in ROS containing solutions when compared with Ti‐6Al‐4V based biomaterials. [ABSTRACT FROM AUTHOR]

Inter‐particle secondary crosslinks allow microporous annealed particle (MAP) hydrogels to be formed. Methods to introduce secondary crosslinking networks in MAP hydrogels include particle jamming, annealing with covalent bonds, and reversible noncovalent interactions. Here, we investigate the effect of two different approaches to secondary crosslinking of polyethylene glycol (PEG) microgels via reversible guest‐host interactions. We generated a dual‐particle MAP‐PEG hydrogel using two species of PEG microgels, one functionalized with the guest molecule, adamantane, and the other with the host molecule, β‐cyclodextrin (Inter‐MAP‐PEG). In a different approach, a mono‐particle MAP‐PEG hydrogel was generated using one species of microgel functionalized with both guest and host molecules (Intra‐MAP‐PEG). The Intra‐MAP‐PEG formed a homogenous distribution due to the single type of microgels used. We then compared the mechanical properties of these two types of MAP‐PEG hydrogels and found that Intra‐MAP‐PEG resulted in significantly softer gels with lower yield stress. We investigated the effect of intra‐particle guest‐host interactions through titrated weight percentage and the concentration of functional groups added to the hydrogel. We found that there was an ideal concentration of guest‐host molecules that enables intra‐ and inter‐particle guest‐host interactions with sufficient covalent crosslinking. Based on these studies, Intra‐MAP‐PEG provides a homogeneous guest‐host hydrogel that is shear‐thinning with reversible secondary crosslinking. [ABSTRACT FROM AUTHOR]

Though magnetic iron oxide nanoparticles (IONPs) are approved for clinical use as contrast agents for MR imaging in United States and Europe, and are widely used to label cells in research, the relationship between IONPs and mesenchymal stem cells (MSCs) is not fully addressed. Here the effects of consistently appeared γ‐Fe2O3 on the lineage commitment of MSCs were studied to optimize applications of IONPs in MSCs upon verification of viability. 30 nm 10 μg/mL induced highest promotions on osteogenesis, while 30 and 50 nm of 100 μg/mL elicited most chondrogensis in 14 days, where the effects on ALP, GAG and SOX9 appeared after 7 days, while on RUNX2 came out after 10 days. γ‐Fe2O3 enhanced intracellular and extracellular Fe3+ and ROS, modulated F‐actin and decreased Lamin A of MSCs at different time scale. The disturbances of F‐actin, Lamin A or ROS altered the effects of γ‐Fe2O3 on MSC differentiation. Our results demonstrate that different size, concentration and modulation of γ‐Fe2O3 are needed in its MSC applications for bone and cartilage tissues. Furthermore, an undocumented phenomenon that the modulation of F‐actin affected the Lamin A expression in MSCs was observed. [ABSTRACT FROM AUTHOR]

Abstract: Metals are widely used in electrode design for recording neural activities because of their excellent electrical conductivity and mechanical strength. However, there are still serious problems related to these currently used metallic electrodes, including tissue damage due to the mechanical mismatch between metals and neural tissues, fibrosis, and electrode fouling and encapsulation that lead to the loss of signal and eventual failure. In this study, a biocompatible, biodegradable, and conductive electrode was created. Specifically, pure magnesium (Mg) microwire with a diameter of 127 µm was used as the electrode substrate and the conductive polymer, that is, poly(3,4‐ethylenedioxythiophene) (PEDOT), was electrochemically deposited onto Mg microwires to decrease corrosion rate and improve biocompatibility of the electrodes for potential neural electrode applications. Both chronopotentiometry and cyclic voltammetry (CV) methods and the associated parameters for electrochemical deposition of PEDOT onto Mg microwires were investigated, such as deposition current, deposition temperature, voltage, sweep rate, cycle number, and duration. The CV method from −2.0 to 1.25 V for 1 cycle at a cycle duration of 600 s with a sweep rate of 5 mV/s at 65°C led to a consistent, uniform, and complete PEDOT coating on Mg microwires. The surface conditions of Mg microwires also affected the quality of PEDOT coating. The corrosion rate of PEDOT‐coated Mg microwire was 0.75 mm/year, much slower than the noncoated Mg microwire that showed a corrosion rate of 1.78 mm/year. The optimal Mg microwires with PEDOT coating could potentially serve as biodegradable electrodes for neural recording and stimulation applications. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1887–1895, 2018. [ABSTRACT FROM AUTHOR]

Due to the aging of population, materials able to repair damaged tissues are needed. Among others, bioactive glasses (BGs) have attracted a lot of interest due to their outstanding properties both for hard and soft tissues. Here, for the first time, two new BGs, which gave very promising results in preliminary in vitro‐tests, were implanted in animals in order to evaluate their regenerative potential. The new BGs, named BGMS10 and Bio_MS and containing specific therapeutic ions, were produced in granules and implanted in rabbits' femurs for up to 60 days, to test their biocompatibility and osteoconduction. Additionally, granules of 45S5 Bioglass® were employed and used as a standard reference for comparison. The results showed that, after 30 days, the two novel BGs and 45S5 displayed a similar behavior, in terms of bone amount, thickness of new bone trabeculae and affinity index. On the contrary, after 60 days, 45S5 granules were mainly surrounded by wide and scattered bone trabeculae, separated by large amounts of soft tissue, while in BGMS10 and Bio_MS the trabeculae were thin and uniformly distributed around the BG granules. This latter scenario could be considered as more advantageous, since the features of the two novel BG granules allowed for the neo‐formation of a uniformly distributed bony trabeculae, predictive of more favorable mechanical behavior, compared to the less uniform coarse trabeculae, separated by large areas of soft tissue in 45S5 granules. Thus, BGMS10 and Bio_MS could be considered suitable products for tissue regeneration in the orthopedic and dental fields. [ABSTRACT FROM AUTHOR]

One of the most important parts of the body is the peripheral nervous system, and any injuries in this system may result in potentially lethal consequences or severe side effects. The peripheral nervous system may not rehabilitate the harmed regions following disabling disorders, which reduce the quality of life of patients. Fortunately, in recent years, hydrogels have been proposed as exogenous alternatives to bridge damaged nerve stumps to create a useful microenvironment for advancing nerve recovery. However, hydrogel‐based medicine in the therapy of peripheral nerve injury still needs a lot of improvement. In this study, GelMA/PEtOx hydrogel was used for the first time to deliver 4‐Aminopyridine (4‐AP) small molecules. 4‐AP is a broad‐spectrum potassium channel blocker, which has been demonstrated to increase neuromuscular function in patients with various demyelinating disorders. The prepared hydrogel showed a porosity of 92.2 ± 2.6% after 20 min, swelling ratio of 456.01 ± 2.0% after 180 min, weight loss of 81.7 ± 3.1% after 2 weeks, and good blood compatibility as well as sustainable drug release. MTT analysis was performed to assess the cell viability of the hydrogel and proved that the hydrogel is an appropriate substrate for the survival of cells. In vivo studies were performed for functional analysis and the sciatic functional index (SFI) as well as hot plate latency results showed that the use of GelMA/PEtOx+4‐AP hydrogel enhances the regeneration compared to the GelMA/PEtOx hydrogel and the control group. [ABSTRACT FROM AUTHOR]

The human amniotic membrane dressing has been shown to accelerate the wound healing process in the clinic. In this study, heparin was conjugated to a human Acellular Amniotic Membrane (hAAM) to provide affinity binding sites for immobilizing growth factors. To study the acceleration of the wound healing process, we bound epidermal growth factor and fibroblast growth factor 1 to heparinized hAAMs (GF‐Hep‐hAAMs). The heparinized hAAMs (Hep‐hAAMs) were characterized by toluidine blue staining and infrared spectroscopy. The quality control of hAAM was performed by hematoxylin staining, swelling capacity test and biomechanical evaluation. The cytotoxicity, adhesion, and migration in vitro assays of GF‐Hep‐hAAMs on L‐929 fibroblast cells were also studied by MTT assay, scanning electron microscopy, and scratch assay, respectively. Finally, in vivo skin wound healing study was performed to investigate the wound closure rate, re‐epithelization, collagen deposition, and formation of new blood vessels. The results showed that GF‐Hep‐hAAMs enhance the rate of wound closure and epidermal regeneration in BALB/c mice. In conclusion, GF‐Hep‐hAAMs could accelerate the wound healing process, significantly in the first week. [ABSTRACT FROM AUTHOR]