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In order to prepare the absorbable medical textile material with different degradation rates, two biopolymers of poly L-lactic acid (PLLA) and polycaprolactone (PCL) with different degradation rates, were mixed in different proportions, and made into PLLA/PCL masterbatch. The experiment of degradation in vitro was conducted to reveal the degradation behaviour of PLLA/PCL masterbatch, and the characteristics of masterbatch in degradation, such as surface morphol- ogy, chemical structure, crystallization, mass loss and strength, were analyzed. The results indicated that the surface of PLLA/PCL masterbatch was etched in degradation, and the larger proportion of PCL, the less etching and slower degra- dation. The ester bonds were hydrolyzed firstly, and the crystallization region in PLLA/PCL masterbatch was destroyed gradually to form a non-crystalline region in degradation. The degradation rate of PLLA in composite masterbatch was faster than that of PCL. With increasing of PCL involved in masterbatch, the mass loss rate of masterbatch in degrada- tion decreased. In addition, the more PCL involved in composite masterbatch, the lower breaking strength.

This trial was conducted to investigate the effect of mannose oligosaccharides (MOS) on the growth performance, antioxidation, immunity and disease resistance of Vibro Parahemolyticus in juvenile abalone Haliotis discus hannai Ino. Four formulated diets were produced to contain 0.00 g/kg, 0.40 g/kg, 0.80 g/kg and 1.60 g/kg Actigen®, with functional ingredients of MOS, respectively. Accordingly, the experimental diets were named as A0, A4, A8 and A16. After 120-days feeding trial, the best growth performance was observed in A8 group (P 0.05) and there was no significant difference in A0, A4 and A16 groups. With the increase of dietary MOS, the activity of the total antioxidant capacity in hepatopancreas is increasingly elevated (P 0.05) while no significant difference was observed on activity of glutathione S-transferase (P 0.05). The activities of superoxide dismutase and glutathione peroxidase were firstly increased and then decreased, with the highest values in A8 group (P 0.05). Immune-related parameters were significantly affected by dietary MOS inclusion. Specifically, the activities of alkaline phosphatase and acid phosphatase in hepatopancreas and serum of abalone fed diets containing MOS were significantly higher than those of control A0 group (P 0.05). Moreover, the highest values of both enzymes were observed in hepatopancreas of A8 group but in serum of A16 group, respectively. The lysozyme activities in hepatopancreas and serum of A4 group were significantly higher than those of other groups (P 0.05) and there was no significant difference in A0, A8 and A16 groups (P 0.05). The activities of cytophagy and respiratory burst in serum of abalone were not significantly affected by dietary MOS content (P 0.05). The mRNA levels of focal adhesion kinase and integrin-linked kinase were gradually elevated with the increase of dietary MOS, with the highest value recorded in A16 group (P 0.05). The gene expression of caspse-3 in A8 group was dramatically higher than those of other groups (P 0.05) and there was no significant difference in A0, A4 and A16 groups (P 0.05). The mRNA level of nuclear factor-κB was not significantly affected by dietary MOS (P 0.05). During 56 h of V. Parahemolyticus challenge period, the accumulated mortality rate of abalone fed diets containing MOS were significantly lower than that of control A0 group in each time point (P 0.05). Overall, the lowest rate was happened in A8 group (P 0.05). In conclusion, MOS inclusion in diet has obviously positive effect on growth, immunity and disease resistance capability of abalone, with the optimal level of Actigen® at 0.80 g/kg in diet.

The basalt fibers/poly (lactic acid) composites, as a kind of green environment friendly materials, were prepared by vacuum perfusion method. The effect of silane coupling agent KH550 on the interface of BFs/PLA composites was analyzed. We observed the microstructure of the surface of BFs treated by silane KH550 and the interface of the composites, explored the chemical reaction among silane KH550, BFs and PLA. The silane KH550 succeeded in linking BFs and PLA and enhanced the interfacial bonding strength between BFs and PLA matrix. The crystalline properties of KH550-treated BFs/PLA composites were better than untreated BFs/PLA composites. The mechanical test suggested the silane KH550 had good effect on strengthening BFs/PLA composites.

Polylactic acid (PLA) surgical suture can be absorbed by human body. In order to avoid surgical site infections (SSIs), the drug is usually loaded on the PLA suture, and then the drug can release directly to the wound. Because the different types of wounds heal at different times, it is needed to control the drug release rate of PLA suture to consistent to the wound healing time. Two biopolymers, polyglycolide (PGA) and polycaprolactone (PCL), were selected as the carrier of ciprofloxacin (CPFX) drug, and then the CPFX-PCL/PGA was coated on the PLA suture. The degradation rate of drug-carrier can be controlled by adjusting the proportion of PCL/PGA, which can regulate the rate of CPFX drug release from PLA suture. The results show that the surface of PLA suture, coating with PCL/PGA, was very rough, which led to increased stitching resistance when we were suturing the wound. These materials, such as the PLA suture, the PCL/PGA carriers and the CPFX drug, were just physically mixed rather than chemically reacted, which was very useful for ensuring the original efficacy of CPFX drug. With the increasing of PCL in the carriers, both the breaking strength and elongation of these un-degraded sutures increased. During degradation, the breaking strength of all sutures gradually decreased, and the more PCL in the coating materials, the longer effective strength-time for the suture. With the increasing of PCL in the drug-carrier, the rate of drug releasing became lower. The drug release mechanism of CPFX-PCL/PGA was a synergistic effect of drug diffusion and PCL/PGA carrier dissolution.

Poly(lactic acid) (PLA) suture can be absorbed by the human body, and so have wide applications in modern surgery operations. The degradation period of PLA suture is expected to meet with the healing time of different types of wounds. In order to control the degradation period of the PLA suture, the carbon nanotubes (CNTs) were composited with PLA suture, and the degradation experiment in vitro was performed on sutures. The structure and properties of sutures during degradation, such as surface morphology, breaking strength, elongation, mass and chemical structure, were tracked and analyzed. The results indicated that the degradation brought about surface defects and resulted in 13.5 weeks for the strength valid time of the original PLA suture. By contrast, the strength valid time of the CNTs/PLA suture was increased to 26.6 weeks. Whilst the toughness of both the pure PLA and CNTs/PLA sutures decreased rapidly and almost disappeared after 3 to 4 weeks of degradation. The mass loss demonstrated that the time required for complete degradation of the two sutures was obviously different, the pure PLA suture 49 weeks, while CNTs/PLA sutures 63 to 73 weeks. The research proved that CNTs delayed PLA degradation and prolonged its strength valid time in degradation.