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The promotion of vascular network formation in the early stages of implantation is considered a prerequisite for successful functional bone regeneration.

Diabetes is a universal disease in the world. In the wounds of diabetic individuals, chronic inflammation and an inefficient fibrogenic process hinder the formation and deposition of the ECM, which delays the process of wound healing. To reconstruct the ECM of a diabetic patient's wound, in this work, we designed a pH-responsive "Double H-bonds" (hydrogen bond and hydrazone bond) hyaluronic acid-collagen hydrogel. This hydrogel can be self-gelled quickly in neutral and alkaline environments. But the weakly acidic inflammatory environment of diabetic wounds may accelerate the degradation of the hydrogel and the release of metformin. The

Effective and fast osseointegration is important for the survival of titanium-based orthopaedic implants. Previous studies confirmed that topographic features combined with inorganic ions showed positive effects on the biological functions of osteoblastic cells. In this study, we report an approach for fabricating Fe-incorporated micro-nano hierarchical structures on titanium substrates, which was realized by dual acid etching and subsequent hydrothermal treatment. The surface morphology, surface chemistry and wettability of the titanium substrates were characterized using scanning electron microscopy, X-ray photoelectron spectroscopy and contact angle measurements, respectively. The Fe-incorporated micro-nano hierarchical titanium substrates were probed to be biocompatible and positively improved protein adsorption, cell proliferation and cell differentiation of osteoblasts in vitro. Furthermore, the Fe-incorporated titanium substrates significantly enhanced the expressions of osteogenic genes (such as Runx2, Col I, OPN, and OCN), which were attributed to the synergistic effects of micro-nano structures and Fe ions. More importantly, the Fe-incorporated titanium implants with micro-nano hierarchical structures promoted new bone formation in vivo. This study provides an alternative for the development of orthopaedic implants with improved osseointegration for potential clinical applications.

In this work, we report a novel strategy to construct cell pattern on titanium substrates by using upconversion nanoparticles (UCNPs). When irradiating with a NIR laser (980 nm) through a photomask, the UCNPs could transfer NIR light into UV light in situ, which results in photocleavage and detachment of unsheltered cells for the formation of cell pattern. This work provides a new perspective for the application of UCNPS in biomedical field.

In this study, a simple one-step co-deposition process was introduced to fabricate antibacterial surfaces for synthetic materials via UV-inducing dopamine polymerization combined with in situ formation of Ag nanoparticles. The successful formation of a composite coating was demonstrated by scanning electron microscopy. Antibacterial experiments including antibacterial rate test and bacteria adhesion were evaluated in vitro. The results confirmed the excellent antibacterial property of this surface modification process. In conclusion, the approach presented here provides a simple and effective approach to construct antibacterial surfaces for synthetic materials to meet the requirements of daily life and industry application.

The immune response to an orthopedic implant is closely related to the nearby bone metabolism balance. To modify titanium (Ti) substrates and accordingly regulate the balance between osteoclast activation and osteoblast differentiation, a multifunctional peptide OGP-NAC was synthesized via conjugating an osteogenic growth peptide (OGP) with N-acetylcysteine (NAC). Then, the synthesized peptide was employed to functionalize Ti substrates and the response of both osteoblasts and osteoclasts was investigated in vitro. The results showed that OGP-NAC was successfully prepared and immobilized onto Ti substrate surfaces. Thereafter, studies on introducing RAW 264.7 cells (one kind of monocyte macrophage responsible for immune responses) to osteoclasts demonstrated that the peptide modified Ti surface could inhibit RAW 264.7 cells from secreting important inflammatory cytokines (TNF-α and IL-1β), and suppress the activation of MAPK, NF-κB and NFAT c1, which are important transcription factors for osteoclastogenesis. Meanwhile, the modified surface promoted osteoblast spreading, proliferation and differentiation. The study offers a feasible strategy to mediate the balance between osteoclast activation and osteoblast differentiation, having great potential for improving osseointegration of an orthopedic implant.

Bone defects/fractures are common in older people suffering from osteoporosis. Traditional hydroxyapatite (HA) materials for osteoporotic bone repair face many challenges, including limited bone formation and aseptic loosening of orthopedic implants. In this study, a new multifunctional HA is synthesized by spontaneous assembly of alendronate (AL) and Fe3O4 onto HA nanocrystals for osteoporotic bone regeneration. The chemical coordination of AL and Fe3O4 with HA does not induce lattice deformation, resulting in a functionalized HA (Func-HA) with proper magnetic property and controlled release manner. The Func-HA nanocrystals have been encapsulated in polymer substrates to further investigate their osteogenic capability. In vitro and in vivo evaluations reveal that both AL and Fe3O4, especially the combination of two functional groups on HA, can inhibit osteoclastic activity and promote osteoblast proliferation and differentiation, as well as enhance implant osseointegration and accelerate bone remodeling ...

In this study, dextran sulfate (DS)/chitosan (CHI) multilayer films were fabricated on TiN-coated NiTi alloy to reduce Ni ion release and improve biocompatibility. The successful formation of TiN coating and DS/CHI multilayer films was demonstrated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Inductively coupled plasma mass spectrometry (ICP-MS) test showed that the Ni ion release from NiTi alloy significantly decreased after surface modification. Cytocompatibility including osteoblasts adhesion and differentiation function was evaluated in vitro. The results suggest that this surface modification process is beneficial for osteoblasts growth on NiTi alloy substrate. The approach presented here provides an attractive way for surface modification of NiTi alloy to meet the requirements of biomedical applications.

To enhance corrosion resistance of WE43 magnesium alloy, chitosan (CHI) and poly (styrene sulfonate) (PSS) polyelectrolyte multilayers were fabricated on micro-arc oxidation (MAO) treated magnesium alloy substrate via layer-by-layer (LBL) self-assembly technique. Surface morphology and chemical composition of the MAO/LBL composite coating were investigated by scanning electron microscopy (SEM), atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS), respectively. Potentiodynamic polarization test and hydrogen evolution measurement showed that the formed MAO/LBL coating significantly enhanced corrosion resistance of WE43 magnesium alloy in simulated body fluid (SBF). The approach presented here affords an effective alternative for surface modification of magnesium-based materials to meet the requirements of biomaterials applications.

A novel redox responsive controlled drug release system based on magnetic nanoparticles for efficient intracellular anticancer drug delivery is fabricated. Disulfide bonds are employed as intermediate linkers to immobilize PEI/β-CD molecules as nanoreservoirs for drug loading onto magnetic nanoparticles. The endocytotic pathway and endosomal escape of the smart controlled drug release system is proposed.

A new bio-composite of hydroxyapatite reinforced polyamide 66 and high density polyethylene was prepared using melt mixing in a co-rotation twin screw extruder. Two series of composites with different composition were investigated using scanning electronic microscopy, mechanical testing, water absorption and infrared spectrometer. The results showed that the change of composition influenced significantly the properties of the composites by different mechanism. Polyethylene mixing with polyamide matrix induced different microstructure and adjusted water absorption and manufacturability. Hydrogen bonding between hydroxyapatite and the polar groups of polyamide improved the adhesion of interface.

Al 2 O 3 –ZrO 2 ceramic coatings were successfully prepared on WE43 magnesium alloy by cathodic plasma electrolytic deposition (CPED) technique. Surface morphology, elemental and phase composition of the coatings were investigated by scanning electron microscope (SEM), energy disperse spectroscopy (EDS) and X-ray diffraction (XRD). Furthermore, the electrochemical corrosion behavior of the coated magnesium alloy in simulated body fluids was evaluated. The results showed that the ceramic coatings were composed of t -ZrO 2 , α -Al 2 O 3 and γ -Al 2 O 3 phases with rough and coarse surfaces. The potentiodynamic polarization test indicated that corrosion resistance of WE43 magnesium alloy was significantly improved by CPED treatment. The approach presented here should be an attractive way for surface modification of Mg and its alloys.

Nano hydroxyapatite (n-HA) crystals carrying incorporated Fe ions were designed and synthesized by a co-precipitation method. The microstructure and morphology as well as magnetic property of the Fe-incorporated n-HA crystals (denoted as n-Fe-HA) were characterized by TEM, XRD and VSM. The results showed that lattice substitution or incorporation had occurred between Fe ions and n-HA, which was quite different from the mechanical mixture of Fe3O4 nanoparticles and n-HA crystals. The n-Fe-HA with a synthetic molar ratio of 1:2 (calculated by Fe3O4:HA) exhibited a needle like crystal shape and relatively good crystallinity. However, when the molar ratio was up to 1:1, some Fe3O4 nanoparticles were separated from n-Fe-HA crystals. The magnetization measurements showed that n-Fe-HA crystals were in superparamagnetic state, proving that the existence of Fe ions in n-HA crystals contributed to the magnetic properties of n-Fe-HA crystals. As one component of biomedical composite, n-Fe-HA has a potential to promote bone regeneration.