Porous calcium phosphate-collagen composite microspheres for effective growth factor delivery and bone tissue regeneration.

Microspheres are beneficial for filling defects of various shapes and provide a large surface area for cell attachment. Porous microspheres have attracted particular attention because they can deliver cells and bioactive molecules such as growth factors. In this study, BCP-collagen composite microspheres were developed for growth factor delivery in bone regeneration.

Bioactive and mechanically stable hydroxyapatite patterning for rapid endothelialization of artificial vascular graft.

Polymeric vascular grafts have been widely used in the vascular regeneration field because of their ease of application. However, synthetic polymer grafts have the severe problem of low biocompatibility, which may cause delayed endothelialization and hyperplasia. In this study, we fabricated a linear hydroxyapatite (HA) pattern on a silicon wafer and then transferred the pattern to a poly(L-lactic)-acid (PLLA) film for use as a tubular vascular graft.

Enhanced biolubrication on biomedical devices using hyaluronic acid-silica nanohybrid hydrogels.

In this work, highly lubricous hyaluronic acid-silica (HA-SiO) nanohybrid coatings were fabricated through a sequential process consisting of a sol-gel followed by electrophoretic deposition (EPD). SiO nanoparticles were uniformly distributed in the coating layers, and the coating thickness was identified as approximately 1-2 μm regardless of the amount of SiO Incorporation of SiO into the HA polymer matrix enhanced the mechanical stability of the nanohybrid coatings, indicating greater interfacial bonding strength compared to HA coating layers alone. In addition, due to improved stability, the nanohybrid coatings showed excellent biolubrication properties, which were evaluated with a tribological experiment.

Hyaluronic Acid-Based Hybrid Hydrogel Microspheres with Enhanced Structural Stability and High Injectability.

For hydrogel injection applications, it is important to improve the strength and biostability of the hydrogel as well as its injectability to pass easily through the needle. Making gel microspheres is one approach to achieve these improvements. Granulization of a bulk hydrogel is a common procedure used to form microsized particles; however, the nonuniform size and shape cause an uneven force during injection, damaging the surrounding tissue and causing pain to the patients.

Enhanced Osseointegration Ability of Poly(lactic acid) via Tantalum Sputtering-Based Plasma Immersion Ion Implantation.

Poly(lactic acid) (PLA) is the most utilized biodegradable polymer in orthopedic implant applications because of its ability to replace regenerated bone tissue via continuous degradation over time. However, the poor osteoblast affinity for PLA results in a high risk of early implant failure, and this issue remains one of the most difficult challenges with this technology. In this study, we demonstrate the use of a new technique in which plasma immersion ion implantation (PIII) is combined with a conventional DC magnetron sputtering.

Use of thioglycerol on porous polyurethane as an effective theranostic capping agent for bone tissue engineering.

Thiolated biodegradable polyurethane (TG-DPU) was synthesized using a one-pot reaction with thioglycerol adopted as a functionalized chain extender. After characterization of the chemical structure of TG-DPU using proton nuclear magnetic resonance spectroscopy, bone morphogenetic protein (BMP-2) was loaded in the TG-DPU under oxidative conditions to form disulfides between the free thiol of TG-DPU and BMP-2. The interaction between TG-DPU and BMP-2, so-called bioconjugates, was investigated using X-ray photoelectron spectroscopy analysis; the appearance of disulfide (S-S) linkage indicated the formation of a polymer/growth factor conjugate system.

Biomimetic porous Mg with tunable mechanical properties and biodegradation rates for bone regeneration.

The medical applications of porous Mg scaffolds are limited owing to its rapid corrosion, which dramatically decreases the mechanical strength of the scaffold. Mimicking the bone structure and composition can improve the mechanical and biological properties of porous Mg scaffolds. The Mg structure can also be coated with HA by an aqueous precipitation coating method to enhance both the corrosion resistance and the biocompatibility.

Fluorine-ion-releasing injectable alginate nanocomposite hydrogel for enhanced bioactivity and antibacterial property.

The creation of a moist environment and promotion of cell proliferation and migration together with antibacterial property are critical to the wound-healing process. Alginate (Alg) is an excellent candidate for injectable wound dressing materials because it can form a gel in a mild environment. Taking advantage of its gelation property, an injectable nano composite hydrogel containing nano-sized (about 90 nm) calcium fluoride (CaF) particles was developed using in-situ precipitation process.

Effective Wound Healing by Antibacterial and Bioactive Calcium-Fluoride-Containing Composite Hydrogel Dressings Prepared Using in Situ Precipitation.

In this study, we report the development of a hyaluronic acid (HA)-based composite hydrogel containing calcium fluoride (CaF) with good biocompatibility and antibacterial properties for multifunctional wound dressing applications. CaF was newly selected for incorporation within HA because it can release both Ca and F ions, which are well-known ions for affecting cell proliferation and inhibiting bacterial growth, respectively. In particular, an in situ precipitation process enables easy control over the released amount of F ions by simply adjusting the precursor solutions (calcium chloride (CaCl) and ammonium fluoride (NHF)) used for the CaF precipitation.

Calcium Phosphate-Collagen Scaffold with Aligned Pore Channels for Enhanced Osteochondral Regeneration.

This study reports the development of a bilayered scaffold with aligned channels produced via a sequential coextrusion and unidirectional freezing process to facilitate upward bone-marrow stem-cell migration. The biomimetic scaffold with collagen and biphasic calcium phosphate (BCP) layers is successfully fabricated with matching of the cartilage and bone layers. The aligned structure results in an enhancement of the compressive strength, and the channels enable tight anchoring of the collagen layers on the BCP scaffolds compared with a randomly structured porous scaffold.

Influence of toxicologically relevant metals on human epigenetic regulation.

Environmental toxicants such as toxic metals can alter epigenetic regulatory features such as DNA methylation, histone modification, and non-coding RNA expression. Heavy metals influence gene expression by epigenetic mechanisms and by directly binding to various metal response elements in the target gene promoters. Given the role of epigenetic alterations in regulating genes, there is potential for the integration of toxic metal-induced epigenetic alterations as informative factors in the risk assessment process.