A Cyclical Magneto-Responsive Massage Dressing for Wound Healing.

Tissue development is mediated by a combination of mechanical and biological signals. Currently, there are many reports on biological signals regulating repair. However, insufficient attention is paid to the process of mechanical regulation, especially the active mechanical regulation in vivo, which has not been realized. Herein, a novel dynamically regulated repair system for both in vitro and in vivo applications is developed, which utilizes magnetic nanoparticles as non-contact actuators to activate hydrogels. The magnetic hydrogel can be periodically activated and deformed to different amplitudes by a dynamic magnetic system. An in vitro skin model is used to explore the impact of different dynamic stimuli on cellular mechano-transduction signal activation and cell differentiation. Specifically, the effect of mechanical stimulation on the phenotypic transition of fibroblasts to myofibroblasts is investigated. Furthermore, in vivo results verify that dynamic massage can simulate and enhance the traction effect in skin defects, thereby accelerating the wound healing process by promoting re-epithelialization and mediating dermal contraction.

A chlorogenic acid-chitosan complex bifunctional coating for improving osteogenesis differentiation and bactericidal properties of zirconia implants.

Poor osteogenesis caused by limited bioactivity and peri-implantitis caused by bacterial colonization are the main challenges affecting the use of zirconia-based materials in dental implants. Accordingly, the development of a surface treatment method with an antibacterial effect and that promotes osteogenesis without damage to cells is crucial for yttrium-stabilized tetragonal zirconia (Y-TZP) implants. Herein, we have developed a functional surface modification strategy whereby a poly (ethylene imine)/hyaluronic acid /chitosan-chlorogenic acid (PEI/HA/CGA-CS) conjugate is deposited on a zirconia surface by the layer-by-layer (LBL) technique, enhancing its osteogenic differentiation and antibacterial activities. The results showed that the PEI/HA/CGA-CS coating improved the wettability of the zirconia surface and maintained stable release of CGA. The PEI/HA/CGA-CS functional coating was found to promote early cell adhesion, proliferation, differentiation, and calcification. The results of bacterial adhesion and activity tests showed that the coating effectively inhibits the proliferation and activity of Porphyromonas gingivalis (P. gingivalis) and Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) without impairing the biological activity of osteoblasts. In addition, we found that the PEI/HA/CGA-CS coating enhances the osteogenesis of MC3T3-E1 cells by promoting the protein expression of Nephronectin (NPNT) and activating the Wnt/ß-catenin signaling pathway. The above results are of profound significance for the practical application of zirconia-based implants. DATA AVAILABILITY: Data will be made available on request.

An injectable photopolymerizable chitosan hydrogel doped anti-inflammatory peptide for long-lasting periodontal pocket delivery and periodontitis therapy.

Periodontitis is a common chronic inflammatory disease caused by plaque that leads to alveolar bone resorption and tooth loss. Inflammation control and achieving better tissue repair are the key to periodontitis treatment. In this study, human ß-Defensin 1 short motif Pep-B with inflammation inhibition and differentiation regulation properties, is firstly used in the treatment of periodontitis, and an injectable photopolymerizable Pep-B/chitosan methacryloyl composite hydrogel (CMSA/Pep-B) is constructed. We confirm that Pep-B improves inflammation, and restores osteogenic behavior and function of injured stem cells. CMSA/Pep-B has good injectability, fluidity and photopolymerizability, and can sustainably release Pep-B to maintain drug concentration in periodontal pockets. Furthermore, animal experiments showed that CMSA/Pep-B significantly ameliorated the inflammation of the periodontium and reduced the alveolar bone loss by decreasing inflammatory infiltration, osteoclast formation and collagen destruction. In conclusion, CMSA/Pep-B is envisaged to be a novel bioactive material or therapeutic drug for treating periodontitis.

Mechanical Properties of Nanohybrid Resin Composites Containing Various Mass Fractions of Modified Zirconia Particles.

PURPOSE: The aim of this study was to investigate the effect of various mass fractions of 10-methacry-loyloxydecyl dihydrogen phosphate (MDP)-conditioned or unconditioned zirconia nano- or micro-particles with different initiator systems on the mechanical properties of nanohybrid resin composites. METHODS: Both light-cured (L) and dual-cured (D) resin composites were prepared. When the mass fraction of the nano- or micro-zirconia fillers reached 55 wt%, resin composites were equipped with dual-cured initiator systems. We measured the three-point bending-strength, elastic modulus, Weibull modulus and translucency parameter of the nanohybrid resin composites containing various mass fractions of MDP-conditioned or unconditioned zirconia nano- or micro-particles (0%, 5 wt%, 10 wt%, 20 wt%, 30 wt% and 55 wt%). A Cell Counting Kit (CCK)-8 was used to test the cell cytotoxicity of the experimental resin composites. The zirconia nano- or micro-particles with MDP-conditioning or not were characterized by transmission electron microscopy (TEM), Fourier infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). RESULTS: Resin composites containing 5-20 wt% MDP-conditioned or unconditioned nano-zirconia fillers exhibited better three-point bending-strength than the control group without zirconia fillers. Nano- or micro-zirconia fillers decreased the translucence of the nanohybrid resin composites. According to the cytotoxicity classification, all of the nano- or micro-zirconia fillers containing experimental resin composites were considered to have no significant cell cytotoxicity. The FTIR spectra of the conditioned nano- or micro-fillers showed new absorption bands at 1719 cm-1 and 1637 cm-1, indicating the successful combination of MDP and zirconia particles. The XPS analysis measured Zr-O-P peak area on MDP-conditioned nano- and micro-zirconia fillers at 39.91% and 34.89%, respectively. CONCLUSION: Nano-zirconia filler improved the mechanical properties of nanohybrid resin composites, but cannot be the main filler to replace silica filler. The experimental dual-cured composites can be resin cements with better opacity effects and a low viscosity.

Effect of APTES- or MPTS-Conditioned Nanozirconia Fillers on Mechanical Properties of Bis-GMA-Based Resin Composites.

To investigate the effects of 3-aminopropyltriethoxysilane (APTES)- or (3-mercaptopropyl)trimethoxysilane (MPTS)-conditioned nanozirconia fillers on the mechanical properties of Bis-GMA-based resin composites. The conditioned fillers were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and thermodynamic calculations. They were then used to prepare Bis-GMA-based resin composites, whose flexural strength and elastic modulus were evaluated. The Cell Counting Kit-8 (CCK-8) assessed the composites' cytotoxicity. The FTIR spectra of the conditioned fillers showed new absorption bands at 1569 and 1100 cm-1, indicating successful grafting of APTES or MPTS onto nanozirconia. XPS confirmed the Zr-O-Si bonds in the APTES- or MPTS-conditioned fillers at contents of 2.02 and 6.98%, respectively. Thermodynamic calculations reaffirmed the chemical binding between the two silanes and nanozirconia fillers. Composites containing the conditioned nanozirconia fillers had significantly greater flexural strengths (APTES, 121.02 ± 8.31 MPa; MPTS, 132.80 ± 15.80 MPa; control, 94.84 ± 9.28 MPa) and elastic moduli (8.76 ± 0.52, 9.24 ± 0.60, and 7.44 ± 0.83 GPa, respectively) than a control with untreated fillers. The cytotoxicity assay identified no significant cytotoxicity by composites containing the conditioned fillers. Silanes were previously considered to be unable to chemically condition zirconia to bond with resin. Inclusion of APTES- or MPTS-conditioned nanozirconia fillers can improve the mechanical properties of Bis-GMA-based resin composites without obvious cytotoxicity in this study.