Polydopamine regulated hydroxyapatite microspheres grown in the three-dimensional honeycomb-like mollusk shell-derived organic template for osteogenesis.

Layered osteochondral composite scaffolds are considered as a promising strategy for the treatment of osteochondral defects. However, the insufficient osseous support and integration of the subchondral bone layer frequently result in the failure of osteochondral repair. Therefore, it is essentially important to explore new subchondral bone constructs tailored to support bone integration and healing. In this study, a novel three-dimensional porous biomimetic construct (HA/pDA-OTMS) was successfully developed by polydopamine (pDA) regulating hydroxyapatite (HA) microspheres grown in the honeycomb-like mollusk shell-derived organic template (OTMS). The biomimetic OTMS had good mechanical properties, high toughness, biodegradability and excellent biocompatibility. Moreover, the long-range ordered cavity structure of OTMS allowed the smallest material to create the largest and most stable geometric space, endowing it high HA loading capacity. The modification of pDA on OTMS surface effectively promoted the mineral nucleation of HA in the micro-nano cavities of OTMS. The compression mechanical tests showed that the combination of inorganic HA and organic pDA-OTMS greatly improved the mechanical properties of the construct. Additionally, the HA/pDA-OTMS composite provided adequate 3-D support for osteoblast cell attachment, proliferation and differentiation, as well as significantly up-regulated the expression of osteogenesis-related genes. These results demonstrated that as-prepared HA/pDA-OTMS constructs with combined mechanical strength and excellent osteogenic activity show great application prospects in subchondral bone regeneration.

Fabrication of Curcumin-Modified TiO2 Nanoarrays via Cyclodextrin Based Polymer Functional Coatings for Osteosarcoma Therapy.

The incomplete removal of bone tumors leads to increased local recurrence and poor prognosis. To prevent ostoperative tumor recurrence and simultaneously repair surgery-caused bone defects, there is a need of great significance to develop implantable biomaterials possessing both cancer cell-killing ability and excellent bioactivity. In this work, a functionalized titanium-based implant is successfully fabricated by loading curcumin (CUR) onto cyclodextrin based polymer (pCD) modified titanium dioxide (TiO2 ) nanorod arrays. Herein, a polydopamine (pDA) assisted film is implemented as a first coating layer onto the surface of the TiO2 nanoarrays to guarantee the robust anchorage of the pCD. The pCD coating acts as a reservoir for CUR, allowing for efficient drug loading and sustained release of anticancer drugs. Studies show that the CUR-modified surfaces (TiO2 /pDA/pCD/CUR) can significantly promote apoptosis of osteosarcoma cells in vitro by inducing mitochondrial dysfunction caused by the ROS overproduction, and meanwhile, effectively inhibit the tumor growth in vivo. Moreover, such functionalized implants with surface density of loaded CUR at 22.48 µg cm-2 or lower support the attachment and proliferation of osteoblasts in vitro. These results successfully demonstrate that as-prepared TiO2 /pDA/pCD/CUR constructs have combined anticancer performance and good biocompatibility, which has great promise for the surgical therapy of bone tumors.

The research about microscopic structure of emulsion membrane in O/W emulsion by NMR and its influence to emulsion stability.

PURPOSE: This paper discussed the influence of microstructure of emulsion membrane on O/W emulsion stability. METHODS: O/W emulsions were emulsified with equal dosage of egg yolk lecithin and increasing dosage of co-emulsifier (oleic acid or HS15). The average particle size and centrifugal stability constant of emulsion, as well as interfacial tension between oil and water phase were determined. The microstructure of emulsion membrane had been studied by (1)H/(13)C NMR, meanwhile the emulsion droplets were visually presented with TEM and IFM. RESULTS: With increasing dosage of co-emulsifier, emulsions showed two stable states, under which the signal intensity of characteristic group (orient to lipophilic core) of egg yolk lecithin disappeared in NMR of emulsions, but that (orient to aqueous phase) of co-emulsifiers only had some reduction at the second stable state. At the two stable states, the emulsion membranes were neater in TEM and emulsion droplets were rounder in IFM. Furthermore, the average particle size of emulsions at the second stable state was bigger than that at the first stable state. CONCLUSIONS: Egg yolk lecithin and co-emulsifier respectively arranged into monolayer and bilayer emulsion membrane at the two stable states. The microstructure of emulsion membrane was related to the stability of emulsion.