Characterization and in-vitro assessment of silicon-based apatite microspheres for bone tissue engineering applications.

In the field of bone tissue engineering, silicon (Si) has been found as an essential element for bone growth. However, the use of silicon in bioceramics microspheres remains limited. In this work, different weight percentages (0.

Optimizing fabrication parameters via Taguchi method for production of high yield hydroxyapatite microsphere scaffolds using Drop-on-Demand inkjet method.

Drop on demand (DOD) inkjet method is a cost-efficient way of producing hydroxyapatite (HAp) microsphere scaffolds with narrow size distribution. However, DOD fabrication parameters may influence the yield and characteristics of the microsphere scaffolds. Testing different permutations and combinations of fabrication parameters is costly and time consuming.

Facile Construction of a Two-in-One Injectable Micelleplex-Loaded Thermogel System for the Prolonged Delivery of Plasmid DNA.

Nanoparticle-hydrogel systems have recently emerged as a class of interesting hybrid materials with immense potential for several biomedical applications. Remarkably, the incorporation of nanoparticles into a hydrogel may yield synergistic benefits lacking in a singular system. However, most synthetic strategies require laborious steps to achieve the system, severely restricting the process of translational research.

Silver-substituted hydroxyapatite inhibits Pseudomonas aeruginosa outer membrane protein F: A potential antibacterial mechanism.

Bone fractures are one of the most common injuries, and they have a big effect on population health worldwide. Traumatic bone injuries can be partially treated with implanting bone-graft substitutes, for example, hydroxyapatite (HA), a bioceramic that is similar materially to natural bones with good bioactivity and osteoconductivity. It could, however, be vulnerable to infections because of the way an HA-based bone graft is put in, which could be a weakness in the host's defense.

Biodegradation of polymers in managing plastic waste - A review.

The modern economy that is fast-moving and convenience centric has led to excessive consumption of plastic. This has unwittingly led to egregious accumulation of plastic waste polluting the environment. Unfortunately, present means of plastic waste management have all been proven as less than adequate; namely recycling, landfill and incineration.

Silver, silicon co-substituted hydroxyapatite modulates bacteria-cell competition for enhanced osteogenic function.

Combating bacteria while promoting tissue regeneration is an aim of highest priority for employing biomaterials in orthopedics that often embroiled with pre-operative contamination. Through simulating a surgical site infection environment and an infected implant site, we showcase the ability of a functionally modified hydroxyapatite, Ag,Si-HA that permits preferential adhesion of human bone marrow derived mesenchymal stem cells (BMSCs) over co-cultured bacterial pathogen,, by displaying immediate suppression and killing of the bacteria present with minimum cytotoxicity for 28 d. And, at the same time, Ag,Si-HA stimulates BMSCs towards osteogenic differentiation despite being within the contaminated milieu.

Surface Design for Antibacterial Materials: From Fundamentals to Advanced Strategies.

Healthcare-acquired infections as well as increasing antimicrobial resistance have become an urgent global challenge, thus smart alternative solutions are needed to tackle bacterial infections. Antibacterial materials in biomedical applications and hospital hygiene have attracted great interest, in particular, the emergence of surface design strategies offer an effective alternative to antibiotics, thereby preventing the possible development of bacterial resistance. In this review, recent progress on advanced surface modifications to prevent bacterial infections are addressed comprehensively, starting with the key factors against bacterial adhesion, followed by varying strategies that can inhibit biofilm formation effectively.

Silicon-incorporated nanohydroxyapatite-reinforced poly(ε-caprolactone) film to enhance osteogenesis for bone tissue engineering applications.

Biomaterials composed of polymers and bioceramics have great prospects to repair large and complicated bone defects. Here, we developed a composite film consisting of poly(ε-caprolactone) (PCL) and silicon-substituted hydroxyapatite (Si-HA) nanoparticles to enhance the osteogenic effects of the scaffold for bone tissue engineering applications. The results showed that the Si-HA nanoparticles obtained an even distribution in the PCL matrix, resulting in a homogeneous composite film.

Effect of copper substitution on the local chemical structure and dissolution property of copper-doped β-tricalcium phosphate.

Substitution of inorganic ions into β-tricalcium phosphate (β-TCP) is a well-known approach for facilitating biological functions of bioceramics. However, the dissolution mechanism of those β-TCPs is still under intensive debates. In the present study, the effect of copper substitution into β-TCP crystal structure on the local chemical structure and dissolution property of the copper-doped β-TCP (CuTCP) was investigated to clarify the dissolution mechanism of β-TCP.

Beta-cyclodextrin modified mesoporous bioactive glass nanoparticles/silk fibroin hybrid nanofibers as an implantable estradiol delivery system for the potential treatment of osteoporosis.

Osteoporosis, a systemic skeletal disease prevalent in elderly women, is associated with post-menopausal estrogen deficiency. Although systemic administration of exogenous estradiol (E2) reduced fragility fractures, the treatment has adverse effects. Localized delivery technologies of E2 could be utilized to circumvent the systemic adverse effects of systemic administration.

Estradiol-Loaded Poly(ε-caprolactone)/Silk Fibroin Electrospun Microfibers Decrease Osteoclast Activity and Retain Osteoblast Function.

Estrogen, a steroid hormone, plays an important role in modulating osteoclast proliferation and development. Estrogen deficiency boosts osteoclast activity, leading to osteoporosis in elderly women. In this study, 17-ß estradiol (E2)-loaded poly(ε-caprolactone) (PCL)/silk fibroin (SF) electrospun microfibers were developed as a proposed localized E2 delivery system to treat osteoporotic fractures.

Fabrication of chelate-setting α-tricalcium phosphate cement using sodium citrate and sodium alginate as mixing solution and its in vivo osteoconductivity.

Moldable and injectable calcium-phosphate cements (CPCs) are material candidates for bone replacement applications. In the present study, we examined the effectiveness of sodium alginate and sodium citrate additives to the liquid phase of CPC, in improving its handling property as well as mechanical strength. The use of these additives enhanced the handling property significantly, in terms of consistency as compared to CPC without additives due to the liquefying effect caused by the adsorption of citrate ions on the cement particles.

Uniaxially Stretched Flexible Surface Plasmon Resonance Film for Versatile Surface Enhanced Raman Scattering Diagnostics.

Surface-enhanced Raman scattering (SERS) spectroscopy affords a rapid, highly sensitive, and nondestructive approach for label-free and fingerprint diagnosis of a wide range of chemicals. It is of great significance to develop large-area, uniform, and environmentally friendly SERS substrates for in situ identification of analytes on complex topological surfaces. In this work, we demonstrate a biodegradable flexible SERS film via irreversibly and longitudinally stretching metal deposited biocompatible poly(ε-caprolactone) film.

Injectable chelate-setting hydroxyapatite cement prepared by using chitosan solution: Fabrication, material properties, biocompatibility, and osteoconductivity.

An injectable chelate-setting hydroxyapatite cement (IP6-HAp), formed by chelate-bonding capability of inositol phosphate (IP6), was developed. The effects of ball-milling duration of starting HAp powder and IP6 concentration on the material properties such as injectability and mechanical strength of the cement were examined. The cement powder was prepared by ball-milling the as-synthesized HAp powder for 5 min using ZrO beads with a diameter of 10 mm, followed by another 60 min with ZrO beads with a diameter of 2 mm, and thereafter surface-modified with 5000 ppm of IP6 solution.

In-vivo evaluation of subcutaneously implanted cell-loaded apatite microcarriers for osteogenic potency.

Cell-loaded apatite microcarriers present as potential scaffolds for direct in-vivo delivery of cells post-expansion to promote bone regeneration. The objective of this study was to evaluate the osteogenic potency of human foetal mesenchymal stem cells (hfMSC)-loaded apatite microcarriers when implanted subcutaneously in a mouse model. This was done by examining for ectopic bone formation at 2 weeks, 1 month and 2 months, which were intended to coincide with the inflammation, healing and remodelling phases, respectively.

A multi-material coating containing chemically-modified apatites for combined enhanced bioactivity and reduced infection via a drop-on-demand micro-dispensing technique.

Prevention of infection and enhanced osseointegration are closely related, and required for a successful orthopaedic implant, which necessitate implant designs to consider both criteria in tandem. A multi-material coating containing 1:1 ratio of silicon-substituted hydroxyapatite and silver-substituted hydroxyapatite as the top functional layer, and hydroxyapatite as the base layer, was produced via the drop-on-demand micro-dispensing technique, as a strategic approach in the fight against infection along with the promotion of bone tissue regeneration. The homogeneous distribution of silicon-substituted hydroxyapatite and silver-substituted hydroxyapatite micro-droplets at alternate position in silicon-substituted hydroxyapatite-silver-substituted hydroxyapatite/hydroxyapatite coating delayed the exponential growth of Staphylococcus aureus for up to 24 h, and gave rise to up-regulated expression of alkaline phosphatase activity, type I collagen and osteocalcin as compared to hydroxyapatite and silver-substituted hydroxyapatite coatings.

Uniformly-dispersed nanohydroxapatite-reinforced poly(ε-caprolactone) composite films for tendon tissue engineering application.

Regeneration of injuries at tendon-to-bone interface (TBI) remains a challenging issue due to the complex tissue composition involving both soft tendon tissues and relatively hard bone tissues. Tissue engineering using polymeric/ceramic composites has been of great interest to generate scaffolds for tissue's healing at TBI. Herein, we presented a novel method to blend polymers and bioceramics for tendon tissue engineering application.

Mechanically-enhanced three-dimensional scaffold with anisotropic morphology for tendon regeneration.

Tissue engineering has showed promising results in restoring diseased tendon tissue functions. Herein, a hybrid three-dimensional (3D) porous scaffold comprising an outer portion rolled from an electrohydrodynamic jet printed poly(ɛ-caprolactone) (PCL) fiber mesh, and an inner portion fabricated from uniaxial stretching of a heat-sealed PCL tube, was developed for tendon tissue engineering (TE) application. The outer portion included three layers of micrometer-scale fibrous bundles (fiber diameter: ~25 µm), with an interconnected spacing and geometric anisotropy along the scaffold length.

Direct E-jet printing of three-dimensional fibrous scaffold for tendon tissue engineering.

Tissue engineering (TE) offers a promising strategy to restore diseased tendon tissue. However, a suitable scaffold for tendon TE has not been achieved with current fabrication techniques. Herein, we report the development of a novel electrohydrodynamic jet printing (E-jetting) for engineering 3D tendon scaffold with high porosity and orientated micrometer-size fibers.

Direct Laser Microperforation of Bioresponsive Surface-Patterned Films with Through-Hole Arrays for Vascular Tissue-Engineering Application.

Tissue architecture plays critical roles in the physiological functions of blood vessels. Surface-patterned films are promising to replicate cellular alignment as in the native vessels. However, for vascular tissue engineering (TE) applications, the current surface-patterned films lack structural support for the myoendothelial communications between tunica media and intima.

Dual-Microstructured Porous, Anisotropic Film for Biomimicking of Endothelial Basement Membrane.

Human endothelial basement membrane (BM) plays a pivotal role in vascular development and homeostasis. Here, a bioresponsive film with dual-microstructured geometries was engineered to mimic the structural roles of the endothelial BM in developing vessels, for vascular tissue engineering (TE) application. Flexible poly(ε-caprolactone) (PCL) thin film was fabricated with microscale anisotropic ridges/grooves and through-holes using a combination of uniaxial thermal stretching and direct laser perforation, respectively.

Development of nanosized silver-substituted apatite for biomedical applications: A review.

Unlabelled: The favorable biocompatibility of hydroxyapatite (HA) makes it a popular bone graft material as well as a coating layer on metallic implant. To reduce implant-related infections, silver ions were either incorporated into the apatite during co-precipitation process (AgHA-CP) or underwent ion-exchange with the calcium ions in the apatite (AgHA-IE). However, the distribution of silver ions in AgHA-CP and AgHA-IE was different, thus affecting the antibacterial action.

Controlled delivery of stromal derived factor-1α from poly lactic-co-glycolic acid core-shell particles to recruit mesenchymal stem cells for cardiac regeneration.

Stromal derived factor-1α (SDF-1α) has shown promising results in treatment of myocardial infarction (MI), via recruitment of endogenous stem cells into the injured myocardium. However, the bioactivity of this susceptible signalling chemokine is reduced significantly during the common fabrication processes of drug delivery systems, due to the exposure to organic-aqueous interfaces or elevated temperature. In this study, we developed a novel SDF-1α delivery system using coaxial electrospraying, the technique which enables fabrication of core-shell particles with minimized contact of organic-aqueous phases.