Folic acid conjugated palygorskite/Au hybrid microgels: Temperature, pH and light triple-responsive and its application in drug delivery.

Herein, folic acid conjugated poly (NIPAM-co-functional palygorskite-Au-co-acrylic acid) (FA-PNFA) hybrid microgels were fabricated by emulsion polymerization. The introduction of acrylic acid can increase the low critical solution temperature (LCST) of FA-PNFA from 36 °C at pH 5.5-42 °C at pH 7.4. Doxorubicin hydrochloride (DOX) was chosen as the load drug, the results show that the DOX release behavior is driven by temperature, pH and light. Cumulative drug release rate can reach 74 % at 37 °C and pH 5.5 while only 20 % at 37 °C and pH 7.4, which effectively avoided the early leakage of the drug. In addition, by exposing FA-PNFA hybrid microgels to laser irradiation, the cumulative release rate was increased by 5 % compared to the release rate under dark conditions. Functional palygorskite-Au as physical crosslinkers not only improves the drug loading content of microgels but also promotes the release of DOX through light drive. Methyl thiazolyl tetrazolium bromide (MTT) assay demonstrated that the FA-PNFA are nontoxic up to 200 µg mL-1 towards 4T1 breast cancer cell. Meanwhile, DOX-loaded FA-PNFA show more significant cytotoxicity than the free DOX. Confocal laser scanning microscope (CLSM) revealed that the DOX-loaded FA-PNFA could be efficiently taken by 4T1 breast cancer cells. FA-PNFA hybrid microgels not only improve the LCST of PNIPAM, but also endow the microgels with photostimulation responsiveness, which can release drugs in response to the triple stimulation response of temperature, pH and light, thus effectively reducing the activity of cancer cells, making them more promising for wider medical applications.

Mechanical properties of a osteoporotic rat model after treated withXianling Gubao Capsule / 中国组织工程研究

BACKGROUND: The effect of Xianling Gubao Capsule for the elderly female osteoporotic animal models assessed by compression and bending mechanical properties is little reported.OBJECTIVE: To investigate the curative efficacy of Xianling Gubao Capsule, alendronate sodium, calcium carbonate and parathyroid hormone (3-34) for an osteoporotic rat model through compressive and bending tests at the femur.METHODS: The rat models of osteoporosis were established by bilateral ovariectomy, and were then subjected to the treatment of Xianling Gubao Capsule, alendronate sodium, calcium carbonate and parathyroid hormone (3-34),respectively, for 20 weeks. Afterwards, the rats were killed by cutting the abdominal aorta, and then the bilateral femurs were removed to undergo compressive and bending tests.RESULTS AND CONCLUSION: The compressive test: the elastic stress, elastic load, elastic strain, elastic displacement,maximum load, maximum strain, maximum stress, maximum displacement and elastic modulus in the model group were significantly lower than those in the blank control, Xianling Gubao Capsule, alendronate sodium and parathyroid hormone (3-34) groups (P < 0.05). The maximum load, maximum strain, maximum stress, and maximum displacement did not differ significantly between Xianling Gubao Capsule and blank control groups (P > 0.05). All indexes in the compressive and bending tests showed no significant differences between model and calcium carbonate groups (P >0.05). Bending test: the maximum load, maximum stress, maximum strain, maximum bending moment and bending section modulus in the model group were significantly lower than those in the blank control, Xianling Gubao Capsule,alendronate sodium and parathyroid hormone (3-34) groups (P < 0.05). The bending mechanical indexes showed no significant differences between Xianling Gubao Capsule and blank control groups (P > 0.05). To conclude, after compressive and bending tests, Xianling Gubao Capsule, alendronate sodium, and parathyroid hormone (3-34) all restore the mechanical properties of the femur, and Xianling Gubao Capsule obtains a significant curative efficacy.