The root-like chitosan nanofiber porous scaffold cross-linked by genipin with type I collagen and its osteoblast compatibility.

Bone tissue repair is difficult due to the dense structure of the extracellular matrix. To solve this problem, a porous chitosan nanofiber scaffold (CSNFS) with an extracellular matrix-like structure was prepared via a facile cross-linked reaction of root-like chitosan nanofiber (CSNF) and collagen (Col) by using genipin (Gen) as the cross-linker. The optimal preparation conditions of CSNFS is weight ratio of CSNF:Col:Gen =1:1:0.1, crosslinked 48 h under 37 °C. CSNFS shows high porosity with adequate micro-scale pores, and its BET data shows that there are a large number of nano-scale pores. The CSNFS mechanical strength is higher than that of the chitosan scaffold both in dry and wet state. MC3T3 cells grow well on CSNFS, can overgrow the scaffold in three-dimensional space, adhere and differentiate well within those nanofiber structure. The cross-linked CSNFS has good biocompatibility and can be used as a repair material for bone tissue engineering.

Organic Solvent-Free Preparation of Chitosan Nanofibers with High Specific Surface Charge and Their Application in Biomaterials.

The application of chitosan nanofibers in biological tissue-engineering materials has attracted wide attention. A novel and organic solvent-free method was developed for the fabrication of rootlike chitosan nanofibers (CSNFs) with diameters of 40-250 nm. This method includes three-step mechanical processing of swelling-beating-centrifugation or swelling-beating-homogenization. The obtained nanofibers showed high yields (>95%) and positive specific surface charges (up to +375 µeq/g) and could be uniformly dispersed in the aqueous phase. The unique fiber shape and the good length-to-diameter ratio of CSNFs endowed chitosan nanofiber paper (CSNFP) products with excellent mechanical properties, and the wet tensile strength of the CSNFPs was nearly five times higher than common chitosan films. In addition, the calvaria-derived preosteoblastic cells exhibited a higher adherence efficiency and proliferation on CSNFP than on chitosan films. The chitosan nanofiber scaffold products also benefited the attachment of preosteoblastic cells and allowed them to grow in three dimensions. This method has significant industrial potential for the industrialization of chitosan nanofibers, which may have broad applications in various biomaterials.

Multifunctional nanoplatform based on star-shaped copolymer for liver cancer targeting therapy.

With high morbidity and death rates, liver cancer has become one of the most common cancers in the world. But, most chemotherapeutic anticancer drugs have high toxicity as well as low specificity. To improve the treatment modalities and enhance the therapeutic effect of liver cancer, a brand new liver-targeting nanoparticle (NP), Ent-11α-hydroxy-15-oxo-kaur-16-en-19-oic acid (5 F)-loaded cholic acid (CA)-functionalized star-shaped poly (lactic-co-glycolic acid) (PLGA)-polyethylene glycol (PEG)-lactobionic acid (LA) (5 F-loaded CA-PLGA-PEG-LA), was developed. The particle size, zeta potential, size distribution, surface morphology, drug loading content, drug encapsulation efficiency and drug release of 5 F-loaded NPs were characterized. Confocal microscopy and flow cytometry showed that the prepared NPs could be internalized by HepG2 cells. Furthermore, the cellular uptake efficiency of coumarin 6-loaded CA-PLGA-PEG-LA NPs was much better in compare with that of CA-PLGA-PEG and CA-PLGA NPs. Moreover, LA-conjugated NPs (CA-PLGA-PEG-LA NPs) enhanced fluorescence of HepG2 cells via ligand-mediated endocytosis. The antitumor effects of 5 F-loaded NPs were evaluated by the MTT assay in vitro and by a xenograft tumor model in vivo, demonstrating that targeted 5 F-loaded CA-PLGA-PEG-LA NPs were significantly superior to free 5 F and 5 F-loaded CA-PLGA-PEG NPs. All the results indicated the 5 F-loaded CA-PLGA-PEG-LA NPs can be employed as a novel potentially targeting drug delivery system for liver cancer therapy.