Antibacterial and angiogenic chitosan microneedle array patch for promoting wound healing.

We have previously shown that the therapeutic range of ultrasound heals osteoradionecrotic bone and induces bone formation in vitro. It is well established that nitric oxide (NO) and prostaglandins are crucial early mediators in mechanically induced bone formation. The therapeutic range of ultrasound may act in the same way; therefore, we have investigated the effect of the therapeutic range of ultrasound on NO induction and prostaglandin E(2) (PGE(2)) production in vitro. Two ultrasound machines were evaluated, "traditional" (1 MHz, pulsed 1:4, tested at four intensities) and a "long-wave" (45 kHz, continuous, also tested at four intensities) devices. Ultrasound was applied to human mandibular osteoblasts for 5 min, and incubated at 37 degrees C for up to 24 h. The control group (sham insonated) was treated in the same way. NO was determined by measuring the nitrite concentration in the culture media colorimetrically, and PGE(2) was assayed by radioimmunoassay. Ultrasound produced a significant increase in both induced nitrite and PGE(2) production. The NO synthesis appeared to be via inducible NO synthase (iNOS) on the basis of the time course and levels of nitrite obtained, although the inhibition of other NOS isoforms by aminoguanidine cannot be excluded. PGE(2) synthesis appeared to be via COX-2. With the 45 kHz machine, a significant increase in NO was achieved at three intensities, 5, 30, and 50 mW/cm(2). The 1 MHz machine stimulated the synthesis of both NO and PGE(2), but was significant at only one dose (0.1 W/cm(2(SAPA))). There was no difference between the two machines with regard to PGE(2) synthesis. The time-course experiment revealed peak production to be 12-18 h for both NO and PGE(2). The therapeutic range of ultrasound stimulates both NO and PGE(2) synthesis by human osteoblasts, and the 45 kHz machine appeared to be more effective than the traditional short-wave length. These results may reflect the healing effect of ultrasound on fractures and osteoradionecrosis.

Ultrasound stimulates nitric oxide prostaglandin E2 production by human osteoblasts

Niacin metal-organic frameworks (MOFs) encapsulated microcapsules with alginate shells and copper-/zinc-niacin framework cores were in situ synthesized by using a microfluidic electrospray approach for wound healing. As the alginate shells were bacteria-responsively degradable, the niacin MOFs encapsulated microcapsules could intelligently, controllably, and programmably release calcium, copper, and zinc ions, depending on the degree of infections. The released ions could not only kill microbes by destroying their membrane and inducing the outflow of nutrient substance, but also activate copper/zinc superoxide dismutase (Cu/Zn-SOD) to eliminate oxygen free radicals and rescue the cells from oxidative stress injury. Furthermore, the simultaneously released niacin could promote hemangiectasis and absorption of functional metal ions. Thus, the niacin MOFs encapsulated microcapsules were imparted with outstanding antibacterial, antioxidant, and angiogenesis properties. Based on an in vivo study, we have also demonstrated that the chronic wound healing process of an infected full-thickness skin defect model could be significantly enhanced by using the niacin MOFs encapsulated microcapsules as therapeutic agent. Therefore, the microfluidic electrospray niacin MOFs encapsulated microcapsules are potential for clinical applications.

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Microfluidic Electrospray Niacin Metal-Organic Frameworks Encapsulated Microcapsules for Wound Healing.

Two dimensional (2D) graphene and its derivatives modification with nanomaterials for formation of hybrid/nanocomposites undergo stimulus-induced optical and electrical changes which are important ...

Cutting edge development on graphene derivatives modified by liquid crystal and CdS/TiO2 hybrid matrix: optoelectronics and biotechnological aspects

Application of graphene-based materials for removal of tetracyclines using adsorption and photocatalytic-degradation: A review.

Graphene has made significant contributions to neural tissue engineering due to its electrical conductivity, biocompatibility, mechanical strength, and high surface area. However, it demonstrates a lack of biological and chemical cues. Also, it may cause potential damage to the host body, limiting its achievement of efficient construction of neural tissues. Recently, there has been an increasing number of studies showing that combining graphene with other materials to form nano-composites can provide exceptional platforms for both stimulating neural stem cell adhesion, proliferation, differentiation and neural regeneration. This suggests that graphene nanocomposites are greatly beneficial in neural regenerative medicine. In this mini review, we will discuss the application of graphene nanocomposites in neural tissue engineering and their limitations, through their effect on neural stem cell differentiation and constructs for neural regeneration.

Graphene-Based Nanocomposites for Neural Tissue Engineering.

Gelatin methacryloyl (GelMA) has attracted the widespread interest of researchers because of its excellent biocompatibility, biodegradability, and moldability Various structures have been constructed from GelMA hydrogel, including 3D scaffold, injectable gel, bio-printed scaffold, and electrospun fibrous membrane via precise fabrication methods such as light-induced crosslinking, extrusion 3D printing, electrospinning, or microfluidics Due to its unique characteristics and simple preparation, GelMA hydrogel demonstrates superior performance and promising potential in a broad range of biomedical applications involving wound healing, drug delivery, biosensing, and tissue regeneration This review integrates sufficient research works on GelMA hydrogels in the regeneration of tissues such as skin, tendon, bone, cartilage, blood vessel, and cardiovascular system, in addition to applications in drug delivery, organ-on-a-chip, and biosensing, providing a critical review of present work and offering future implications

Biomedical applications of gelatin methacryloyl hydrogels

Current periosteal grafts have limitations related to low mechanical strength, tissue adhesiveness, and poor osteogenesis and angiogenesis potential. Here, a periosteum mimicking bone aid (PMBA) with similar structure and function to natural periosteum is developed by electrospinning photocrosslinkable methacrylated gelatin (GelMA), l-arginine-based unsaturated poly(ester amide) (Arg-UPEA), and methacrylated hydroxyapatite nanoparticles (nHAMA). Such combination of materials enhances the material mechanical strength, favors the tissue adhesion, and guarantees the sustained activation of nitric oxide-cyclic guanosine monophosphate (NO-cGMP) signaling pathway, with well-coordinated osteogenic-angiogenic coupling effect for accelerated bone regeneration. This work presents a proof-of-concept demonstration of thoroughly considering the progression of implant biomaterials: that is, the initial material components (i.e., GelMA, Arg-UPEA, and nHAMA) equip the scaffold with suitable structure and function, while its degradation products (i.e., Ca2+ and l-arginine) are involved in long-term mediation of physiological activities. It is envisioned that the strategy will inspire the design of high-performance bioscaffolds toward bone and periosteum tissue engineering.

Biomimetic, Stiff, and Adhesive Periosteum with Osteogenic–Angiogenic Coupling Effect for Bone Regeneration

Recovery from bone, osteochondral, and cartilage injuries/diseases has been burdensome owing to the damaged vasculature of large defects and/or avascular nature of cartilage leading to a lack of nutrients and supplying cells. However, traditional means of treatment such as microfractures and cell-based therapy only display limited efficacy due to the inability to ensure cell survival and potential aggravation of surrounding tissues. Exosomes have recently emerged as a powerful tool for this tissue repair with its complex content of transcription factors, proteins, and targeting ligands, as well as its unique ability to home in on target cells thanks to its phospholipidic nature. They are engineered to serve specialized applications including enhancing repair, anti-inflammation, regulating homeostasis, etc. via means of physical, chemical, and biological modulations in its deriving cell culture environments. This review focuses on the engineering means to functionalize exosomes for bone, osteochondral, and cartilage regeneration, with an emphasis on conditions such as osteoarthritis, osteoporosis, and osteonecrosis. Finally, future implications for exosome development will be given alongside its potential combination with other strategies to improve its therapeutic efficacy in the osteochondral niche.

Bone-a-Petite: Engineering Exosomes towards Bone, Osteochondral, and Cartilage Repair.

Mesoporous silica nanoparticles (MSNs) have been demonstrated to be one of the most promising drug-delivery systems (DDSs) to transport a variety of drugs/biomolecules. Functionalization of MSN surfaces with responsive polymer brushes leads to intelligent and controllable drug-delivery properties, that is, the encapsulated drugs/biomolecules will only be released upon certain stimuli including pH, temperature, light, enzyme, ultrasound, or redox, thus maximizing their therapeutic efficiency and minimizing side effects. These polymer brushes can also increase the stability and extend the release period of the loaded cargoes. This Minireview presents an overview of recent research progress on stimuli-responsive controlled DDSs based on polymer-brush-grafted MSNs. Utilizing the switching abilities of the grafted responsive polymer brushes, the smart DDSs show great potential for biomedical applications, especially for cancer therapy.

Ho Pan Bei

Papers

Graphene-Based Nanocomposites for Neural Tissue Engineering.

Biomedical applications of gelatin methacryloyl hydrogels

Biomimetic, Stiff, and Adhesive Periosteum with Osteogenic–Angiogenic Coupling Effect for Bone Regeneration

Bone-a-Petite: Engineering Exosomes towards Bone, Osteochondral, and Cartilage Repair.

Polymer‐Brush‐Grafted Mesoporous Silica Nanoparticles for Triggered Drug Delivery