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Collagen is a promising material for corneal tissue engineering. The surface topography of collagen is critical for cornea reconstruction and regeneration. Herein, we fabricated collagen films with microgrooved surface to investigate the effect of collagen film topography on corneal cell migration and antifibrosis. We found that the patterned films with microscale grooves could greatly affect the orientation, proliferation, migration, and gene expression of rabbit corneal epithelial cells and keratocytes. Compared with the natural cornea, the optimized collagen films with microgroove pattern show similar swelling performance, optical clarity, and biodegradability, which could efficiently promote the epithelial cell migration, accelerate wound healing process, and inhibit the fibrosis of keratocytes. These results suggest that collagen films with microgroove pattern are promising in corneal tissue engineering.

A series of novel bacterial cellulose/C60 (BCC60) composites was prepared using a original dehydration-rehydration method. The composites were characterized to demonstrate their potential in multifunctional wound dressings for skin cancer treatment using photodynamic therapy. Raman spectroscopy revealed that the C60 nanoparticles were successfully incorporated into the bacterial cellulose (BC) network. Scanning electron microscopy was used to examine the morphology and distribution of the C60 particles as photosensitizers in the bacterial cellulose network, and the C60 particles were uniformly distributed in the hyperfine three-dimensional BC network with diameters less than 100 nm. Reactive oxygen species (ROS) measurements indicated that the BCC60 composites possessed a high ROS generation ability when exposed to light. The antibacterial assessment of the BCC60 composites revealed their ability to inhibit the growth of E. coli and S. aureus and their relationship with light irradiation. In vitro cell experiments also confirmed that the BCC60 composites had low cytotoxicity in the dark, while they exhibited significant cancer cell damage activity under visible light.

A novel bacterial cellulose/collagen–hydroxypropyltrimethyl ammonium chloride chitosan composite (BCC–H), as an ideal artificial hernia mesh, was synthesized by combining solution impregnation with the EDC/NHS chemical crosslinking method. Scanning electron microscopy was used to examine the morphology of the bacterial cellulose/collagen (BCC) and BCC–H composites. Infrared spectroscopy demonstrated that collagen and hydroxypropyltrimethyl ammonium chloride chitosan (HACC) were incorporated into the bacterial cellulose network successfully. Mechanical testing of the materials showed that the addition of HACC made the tensile strength decrease while the elongation at break was increased. Antibacterial assessment of the BCC–H composites revealed distinct growth inhibition against Escherichia coli and Staphylococcus aureus. In vitro cell experiments confirmed that the BCC–H composites had low cytotoxicity and good biocompatibility.

A well-designed scaffold with accurately controlled structure, pore size as well as interconnection plays a key role in tissue engineering. In this study, porous Li-containing biphasic calcium phosphate scaffolds (Li-BCP) with expected structure were fabricated successfully by 3D plotting technique. The results of scanning electron microscopy (SEM) and micro-CT indicated that scaffolds from 3D plotting possessed an elaborate pore structure, porosity and interconnection. Besides, Li-BCP scaffolds also possessed excellent mechanical strength. Furthermore, in vitro cell experiments confirmed that mouse bone mesenchymal stem cells (mBMSCs) cultured on Li-BCP scaffolds exhibited good adhesion and spreading. Moreover, Li-BCP scaffolds could efficaciously promote the proliferation and osteogenic differentiation of mBMSCs, demonstrating their potential applicability as a candidate for bone repair applications.

A series of novel bacterial cellulose/C

Present studies on the topographic effects of substrates on cell functions are limited to planar substrates, which are usually not applicable in bone repair. Specific patterns are rarely constructed on 3D substrates. Here spherical substrates with macroporous topography were obtained to explore cellular responses. Macropores with tunable density were generated on the surfaces of poly(lactic-co-glycolic acid)/hydroxyapatite (PLGA/HA) microspheres by using HA particles as the pore-forming source. Different densities of macropores represented different topographies and were found to influence the morphology, proliferation and osteogenic differentiation of human fetal mesenchymal stem cells (fMSCs). The microspheres with a medium density of macropores most benefitted proliferation and differentiation of fMSCs compared with the low and high density ones. This study reveals the role of macroporous spherical surfaces in affecting cell function and may guide the design of functional substrates in bone repair.

Composite polymer devices have gained considerable interest in biomedical applications. In this work, a composite poly(lactic-co-glycolic acid)/poly(e-caprolactone) (PLGA/PCL) microsphere with a layered architecture and an island–sea topography was developed. PCL was found to occupy the shell layer of the microsphere, while PLGA constituted surface islands and the internal core. This subtle structure was derived from the different external and internal rates of phase separation between PCL and PLGA. The existence of the PLGA islands enhanced the hydrophilicity of the PCL shell. Mouse mesenchymal stem cells (mMSCs) were cultured and they grew well on the PLGA/PCL microspheres. The surface of the microsphere was microscopically composed of PCL sea and PLGA islands, and the mMSCs showed a trend to attach to the more hydrophilic PLGA islands and bridged between adjacent microspheres. This paper provides a new alternative to design functional microspheres for potential application in tissue repair.

Biodegradable polymer microspheres have been increasingly attracting attention in bone repair. In this work, superficially porous poly(lactic-co-glycolic acid)/calcium carbonate (PLGA/CC) composite microsphere is prepared by spontaneous pore-forming emulsion method. In addition to being the component that neutralizes the acidic products from PLGA degradation, calcium carbonate (CC) also constructs macropores on the surface of microsphere and thus exempts the use of extraneous porogens, which simplifies the preparation process and avoids problems related to extraneous porogen. It is found that the size of CC plays the most essential role in forming the superficial macropores because it determines the water absorption capacity of CC. Release of dexamethasone from the superficially porous composite microspheres shows a mild burst and the subsequent tri-phase profile. Meanwhile, the cell culture test demonstrates that MG-63 cells grow well on the superficially porous composite microsphere and proliferate better than those on pure PLGA microsphere. Therefore, this versatile composite microsphere has a promising application for bone repair.