OBJECTIVE: To summarize the biomechanical research progress of biomaterials in rotator cuff injury repair and to explore how biomaterials can restore the native histological and mechanical properties of the rotator cuff. METHODS: The relevant literature at home and abroad was widely reviewed to analyze the biomechanical properties of synthetic biomaterials, naturally derived biomaterials, and tissue grafts in the repair of rotator cuff injuries. RESULTS: Synthetic biomaterials [such as poly (lactic-co-glycolic acid) and polycaprolactone] can provide initial stable mechanical support due to their adjustable mechanical properties and degradation characteristics, while naturally derived biomaterials (such as collagen and hyaluronic acid) can promote cell adhesion and tissue integration due to their biocompatibility and bioactivity. Tissue grafts exhibit significant clinical utility by providing immediate mechanical stability and promoting tendon-to-bone healing. Three-dimensional bioprinting technology provides new possibilities for personalized repair of rotator cuff injuries by precisely controlling the spatial distribution and mechanical properties of biomaterials. CONCLUSION Future studies should further optimize the design of bioprinting materials, cell sources, and scaffolds to achieve better mechanical properties and clinical efficacy of biomaterials in the repair of rotator cuff injuries.
Humans ; Rotator Cuff Injuries ; Biocompatible Materials/chemistry* ; Biomechanical Phenomena ; Tissue Scaffolds ; Rotator Cuff/surgery* ; Tissue Engineering/methods* ; Polyesters ; Polyglycolic Acid/chemistry* ; Hyaluronic Acid/chemistry* ; Collagen/chemistry* ; Lactic Acid/chemistry* ; Polylactic Acid-Polyglycolic Acid Copolymer ; Bioprinting ; Wound Healing ; Printing, Three-Dimensional ; Tendon Injuries/surgery*

Biorefinery of chemicals from straw is an effective approach to alleviate the environmental pollution caused by straw burning. In this paper, we prepared gellan gum immobilized Lactobacillus bulgaricus T15 gel beads (LA-GAGR-T15 gel beads), characterized their properties, and established a continuous cell recycle fermentation process for D-lactate (D-LA) production using the LA-GAGR-T15 gel beads. The fracture stress of LA-GAGR-T15 gel beads was (91.68±0.11) kPa, which was 125.12% higher than that of the calcium alginate immobilized T15 gel beads (calcium alginate-T15 gel beads). This indicated that the strength of LA-GAGR-T15 gel beads was stronger, and the strain was less likely to leak out. The average D-LA production was (72.90±2.79) g/L after fermentation for ten recycles (720 h) using LA-GAGR-T15 gel beads as the starting strain and glucose as the substrate, which was 33.85% higher than that of calcium alginate-T15 gel beads and 37.70% higher than that of free T15. Subsequently, glucose was replaced by enzymatically hydrolyzed corn straw and fermented for ten recycles (240 h) using LA-GAGR-T15 gel beads. The yield of D-LA reached (1.74±0.79) g/(L·h), which was much higher than that of using free bacteria. The wear rate of gel beads was less than 5% after ten recycles, which indicated that LA-GAGR is a good carrier for cell immobilization and can be widely used in industrial fermentation. This study provides basic data for the industrial production of D-LA using cell-recycled fermentation, and provides a new way for the biorefinery of D-LA from corn straw.
Fermentation ; Lactobacillus delbrueckii ; Zea mays ; Lactic Acid ; Alginates/chemistry* ; Glucose

Polylactic acid is synthesized indirectly by the polymerization method, according to the standard GB/T 16886.18-2011, the evaluation parameters and methods about chemical characterization of polylactic acid have been established. By using rigorous and comprehensive comparative analysis, the chemical equivalency of domestic and imported polylactic acid materials has been proved, along with the "Medical Device Biology Evaluation and Review Guide", paving the way of using domestic polylactic acid in implantable medical devices.
Equipment and Supplies ; Lactic Acid ; Polyesters ; chemistry ; Polymers

OBJECTIVE: To establish an animal model for loaded swimming, so as to investigate the energy metabolism effects of soybean isoflavones (SI) on swimming mice. METHODS: Thirty male Kunming mice were randomly divided into three groups:normal control, swimming group, and swimming+SI group. The normal control group mice were fed a basic AIN-93M diet, the SI groups were supplied with soybean isoflavones(4 g/kg).Two weeks later, the mice were forced to swim for an hour,and then all the mice were killed, the samples of blood, liver and muscles of hind were collected.The serum contents of lactic acid(Lac), the activities of lactic dehydrogenase (LDH), succinate dehydrogenase (SDH), creatine kinase (CK) and ATPase were measured. RESULTS: Compared with normal control,the serum content of Lac was significantly improved in the group of the swimming control and SI(<0.05),the activity of LDH in the serum was obviously improved in the group of the swimming control and SI, and the activity of CK and SDH were both significantly improved in the group of the swimming control and SI except the activity of SDH in the liver of the group SI; compared with the swimming control,the serum contents of Lac,the activities of LDH, ATPase, SDH, CK were obviously improved(<0.05). CONCLUSIONS Soybean isoflavones can improve the energy metabolism,antioxidant capacity of the swimming mice.
Adenosine Triphosphatases ; blood ; Animals ; Creatine Kinase ; blood ; Energy Metabolism ; Isoflavones ; pharmacology ; L-Lactate Dehydrogenase ; blood ; Lactic Acid ; blood ; Male ; Mice ; Random Allocation ; Soybeans ; chemistry ; Succinate Dehydrogenase ; blood ; Swimming

As the carrier of water-insoluble drugs, microspheres can play a role in increasing solubility and delaying releasing essence. The objective of this study was to improve the solubility and to delay the release of a newly discovered antitumor compound 3β-hydroxyolea-12-en-28-oic acid-3, 5, 6-trimethylpyrazin-2-methyl ester (T-OA). Early-stage preparation discovery concept (EPDC) was employed in the present study. The preparation, physicochemical characterization, and drug release properties of PLGA microspheres were evaluated. T-OA-loaded PLGA microspheres were prepared by an oil-in-water (O/W) emulsification solvent evaporation method. Characterization and release behaviors of the T-OA PLGA microspheres were evaluated by X-ray diffract (XRD), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and high performance liquid chromatography (HPLC). The results demonstrated that T-OA-loaded PLGA microspheres could be successfully obtained through solvent evaporation method with appropriate morphologic characteristics and high encapsulation efficiency. The XRD analysis showed that T-OA would be either molecularly dispersed in the polymer or distributed in an amorphous form. The DSC and FTIR analysis proved that there were interactions between T-OA and PLGA polymer. SEM observations displayed the morphology of the microspheres was homogeneous and the majority of the spheres ranged between 50 and 150 μm. The drug release behavior of the microspheres in the phosphate buffered saline medium exhibited a sustained release and the duration of the release lasted for more than 23 days, which was fit with zero-order release pattern with r = 0.9947. In conclusion, TOA-loaded PLGA microspheres might hold great promise for using as a drug-delivery system in biomedical applications.
Antineoplastic Agents ; chemistry ; Calorimetry, Differential Scanning ; Chemistry, Pharmaceutical ; Delayed-Action Preparations ; chemistry ; Drug Carriers ; chemical synthesis ; chemistry ; Lactic Acid ; chemical synthesis ; chemistry ; Microscopy, Electron, Scanning ; Microspheres ; Oleanolic Acid ; chemistry ; Polyglycolic Acid ; chemical synthesis ; chemistry ; Polylactic Acid-Polyglycolic Acid Copolymer ; Pyrazines ; chemistry ; Solubility ; Spectroscopy, Fourier Transform Infrared ; X-Ray Diffraction

OBJECTIVETo evaluate the effect of 2-methacryloyloxyethyl phosphorylcholine (MPC) and nanoparticles of amorphous calcium phosphate (NACP) on the protein-repellent property of dental adhesive.

METHODSMPC and NACP were incorporated into SBMP as the test group. Scotchbond Multi-Purpose (SBMP) was used as control group. Human dentin shear bond strengths were measured. Protein adsorption onto samples was determined by micro bicinchoninic acid (BCA) method. A dental plaque microcosm biofilm model with human saliva as inoculum was used to investigate biofilm viability.

RESULTSThe dentin bond strength of modified group was (28.7±2.2) MPa, which was not significantly different from that of the SBMP control group. The amount of protein adsorption in the modified group and the SBMP control group were (0.21±0.02) µg/cm(2) and (4.17±0.45) µg/cm(2) respectively. Lactic acid production of biofilms in modified group and SBMP control were (7.71 ± 1.01) mmol/L and (19.18 ± 2.34) mmol/L repectively.

CONCLUSIONSMPC-NACP based dental adhesive greatly reduce the protein adsorption and bacterial adhesion, without compromising dentin shear bond strength. This novel bonding agent may have wide application.

Adsorption ; Biofilms ; drug effects ; growth & development ; Calcium Phosphates ; pharmacology ; Dental Cements ; pharmacology ; Dental Plaque ; Dentin ; chemistry ; Humans ; Lactic Acid ; biosynthesis ; Methacrylates ; pharmacology ; Nanoparticles ; Phosphorylcholine ; analogs & derivatives ; pharmacology ; Resin Cements ; pharmacology ; Saliva ; Tensile Strength

Poly lactic acid (PLA)/Poly (butyleneadipate-co-terephthalate)(PBAT) and glyceryl triacetate (GTA) blend were prepared by torque rheometer, and the effect of GTA on thermodynamical performance, mechanical properties and microstructure of PLA/PBAT composites were studied using differential scanning calorimeter(DSC), dynamic mechanical analysis(DMA), universal testing machine, impact testing machine and scanning electron microscope(SEM). After adding GTA, Tg values of the two phases gradually became closer, blends cold crystallization temperature and melting temperature decreased. When with 3 phr GTA, the dispersed phase particle size of PLA/PBAT blend decreased. Mechanics performance test showed that the elongation at break and impact strength of the PLA/PBAT blend was greatly increased with 3 phr GTA, and the elongation at break increased 2.6 times, improved from 17.7% to 64.1%.
Acetates ; chemistry ; Calorimetry, Differential Scanning ; Crystallization ; Lactic Acid ; Polyesters ; chemistry ; Polymers ; Temperature

Poly (lactic acid) (PLA) is a polymer synthesized from lactic acid with good biocompatibility and biodegradability. At present, PLA manufactured on industrial scale is mainly synthesized from L-lactic acid. The obtained products have good transparency but poor heat resistance. Adding nucleating agents could increase the crystallinity of PLA, to improve heat resistance. We reviewed the progress of research on organic and inorganic nucleating agents that can be used for PLA synthesis.
Chemical Industry ; Lactic Acid ; Polyesters ; chemistry ; Polymers

Poly lactic acid (PLA) fibers a biodegradable fiber produced from PLA resin by melt spinning, solvent spinning or electrostatic spinning. Based on the excellent safety, comfortability, environmental protection and good mechanical properties, PLA can be widely applied in textile fabric, nonwoven, filler fabric and many downstream health products application, such as sanitary napkins, baby diapers, facial masks, and wipes.
Biotechnology ; Chemical Industry ; Lactic Acid ; Polyesters ; chemistry ; Polymers

To study the relation between drug release and the drug status within curcumin-loaded microsphere, SPG (shirasu porous glass) membrane emulsification was used to prepare the curcumin-PLGA (polylactic-co-glycolic acid) microspheres with three levels of drug loading respectively, and the in vitro release was studied with high-performance liquid chromatography (HPLC). The morphology of microspheres was observed with scanning electron microscopy (SEM), and the drug status was studied with X-ray diffraction (XRD), differential scanning calorimetry (DSC) and infrared analysis (IR). The drug loading of microspheres was (5.85 ± 0.21)%, (11.71 ± 0.39)%, (15.41 ± 0.40)%, respectively. No chemical connection was found between curcumin and PLGA. According to the results of XRD, curcumin dispersed in PLGA as amorphous form within the microspheres of the lowest drug loading, while (2.12 ± 0.64)% and (5.66 ± 0.07)% curcumin crystals was detected in the other two kinds of microspheres, respectively, indicating that the drug status was different within three kinds of microspheres. In the data analysis, we found that PLGA had a limited capacity of dissolving curcumin. When the drug loading exceeded the limit, the excess curcumin would exist in the form of crystals in microspheres independently. Meanwhile, this factor contributes to the difference in drug release behavior of the three groups of microspheres.
Calorimetry, Differential Scanning ; Curcumin ; chemistry ; Drug Liberation ; Lactic Acid ; Microscopy, Electron, Scanning ; Microspheres ; Polyglycolic Acid ; X-Ray Diffraction