The observed difference of macrophage phenotype on different surface roughness of mineralized collagen

Biomaterials regulate macrophages and promote regeneration function,which is a new hot pot in tissue engineering and regenerative medicine.The research based on macrophage materials biology has appeared happy future,but related research on regulating macrophages and promoting tissue regeneration is still in its infancy.The surface roughness of biomaterials is one of the important factors affecting macrophage behavior.Previous study also found that the surface roughness of many biomaterials regulating macrophage polarization,but not including mineralized collagen(MC).In this study,we designed and fabricated MC with different roughness and investigated the influence of MC with different roughness on macrophages.In the study,we found that on the rough surface of MC,macrophages exhibited M1 phenotype-amoeboid morphology and high-level secretory of inflammatory factor(tumor necrosis factor-a and interleukin-6),while smoother surface exhibited M2 phenotype.These data will be beneficial to understand the mechanism deeply and enrich biomaterials tissue regeneration theory,provide a new train of thought biomaterials inducing tissue regeneration and repair and guide the optimum design of new biomaterials,development and reasonable applications.

Enhancement of BMP-2 and VEGF carried by mineralized collagen for mandibular bone regeneration

Repairing damage in the craniofacial skeleton is challenging.Craniofacial bones require intramembranous ossification to generate tissue-engineered bone grafts via angiogenesis and osteogenesis.Here,we designed a mineralized collagen delivery system for BMP-2 and vascular endothelial growth factor(VEGF)for implantation into animal models of mandibular defects.BMP-2/VEGF were mixed with mineralized collagen which was implanted into the rabbit mandibular.Animals were divided into(i)controls with no growth factors;(ii)BMP-2 alone;or(iii)BMP-2 and VEGF combined.CT and hisomputed tomography and histological staining were performed to assess bone repair.New bone formation was higher in BMP-2 and BMP-2-VEGF groups in which angiogenesis and osteogenesis were enhanced.This highlights the use of mineralized collagen with BMP-2/VEGF as an effective alternative for bone regeneration.

INTERDIFFUSION KINETICS OF MISCIBLE POLYMER/POLYMER LAMINATES INVESTIGATED BY ATOMIC FORCE MICROSCOPY

The miscibility of poly（vinyl chloride）/poly（n-butyl methacrylate） （PVC/PnBMA） blend and the interdiffusion kinetics of PVC/PnBMA laminates have been investigated by differential scanning calorimetry （DSC） and atomic force microscopy （AFM）, respectively. This blend exhibited a lower critical solution temperature behavior. Below 120 ℃, DSC results showed each blend with different PVC contents exhibited only a single glass transition temperature which increased with PVC content, indicating that PVC and PnBMA were miscible. After PVC/PnBMA laminates were annealed at different temperature for different time, a smooth cross-section across interface was prepared by ultramicrotoming. Combined with topography and phase images of tapping mode AFM, the relative concentration profile, interface width and the relationship between interface width and annealing time could be obtained. In a regime of rubbery/rubbery interdiffusion, the diffusion obeyed a typical Fickian Case-I behavior where the interface width was proportional to the square root of annealing time. The mutual diffusion coefficient was in good agreement with that obtained from DSC and positron annihilation lifetime spectroscopy. However, in the regime of glassy/rubbery interdiffusion, the diffusion followed a typical Case-II behavior where the interface width was proportional to annealing time. These results imply that AFM is a reliable and powerful tool for the investigation of polymer/polymer interdiffusion at a level of polymer chain size.