Preparation and self-assembly of ionic (PNIPAM-co-VIM) microgels and their adsorption property for phosphate ions.

Using N-isopropyl acrylamide (NIPAM) as the main monomer, 1-vinyl imidazole (VIM) containing tertiary amine groups as the functional comonomer, and 1,5-dibromo pentane as the crosslinking agent, ionic P(NIPAM-co-VIM) microgels were prepared by a two-step method. The crosslinking agent was reacted with tertiary amino groups by the quaternary amination. The results of zeta potential and particle size analysis showed that P(NIPAM-co-VIM) microgels were positively charged and had a particle size of about 400 nm, and the microgels with 11 wt% VIM still showed temperature sensitivity with a volume phase transition temperature of approximately 37.5 °C. The effects of VIM content, ambient temperature, and pH on the adsorption properties of the microgels for phosphate anions were explored. The self-assembly of the positively charged P(NIPAM-co-VIM) microgels with polyelectrolytes and the adsorption behavior of the layers for phosphate anions were studied using a quartz crystal microbalance (QCM). It was found that at a phosphate concentration of 0.3 mg mL-1, VIM mass fraction of 11%, pH of 5, and temperature of 20 °C, the largest adsorption capacity of P(NIPAM-co-VIM) microgel on phosphate ions could reach 346.3 mg g-1. The frequency responses of the microgel-modified QCM sensor could reach 3.0, 18.8, and 25.9 Hz when exposed to 10-8, 10-7, and 10-6 M phosphate solutions. Therefore, the ionic (PNIPAM-co-VIM) microgels could be promising for fabricating anion-binding materials for separation and sensing applications.

Facile Preparation and Dye Adsorption Performance of Poly(N-isopropylacrylamide-co-acrylic acid)/Molybdenum Disulfide Composite Hydrogels.

Using N-isopropylacrylamide (NIPAM) and acrylic acid (AAc) as monomers, N,N'-methylenebisacrylamide (MBA) as a cross-linking agent, and molybdenum disulfide (MoS2) as functional particles, a P(NIPAM-co-AAc)/MoS2 composite hydrogel was prepared by free radical polymerization initiated by ultraviolet light. The results of Fourier transform infrared spectroscopy, Raman spectroscopy, and scanning electron microscopy show that MoS2 has been successfully introduced into the P(NIPAM-co-AAc) system, and the obtained composite hydrogel has a porous network structure. Studies on the swelling property and dye adsorption performance show that the addition of MoS2 can increase the swelling ratio of P(NIPAM-co-AAc) hydrogels to a certain extent and can significantly improve the ability of the P(NIPAM-co-AAc) hydrogel to adsorb methylene blue (MB). The adsorption process of MB by the composite hydrogels conforms to the pseudo-second-order kinetics and the Langmuir isotherm adsorption models. The estimated equilibrium adsorption capacity (Q m) using the Langmuir isotherm model can reach 1258 mg/g, mainly due to the electrostatic interaction between the negatively charged groups -COO- and MoS2 particles on the network structure and the positively charged dye MB. The adsorption of MB by P(NIPAM-co-AAc)/MoS2 composite hydrogels depends on the temperature during adsorption. Compared with room temperature, a high temperature of 40 °C above the poly(N-isopropylacrylamide) (PNIPAM) phase transition temperature (∼32 °C) leads to a decreased adsorption capacity of the P(NIPAM-co-AAc)/MoS2 composite hydrogel for MB due to the enhanced hydrophobic properties of the network structure and the decrease of the swelling ratio. The prepared hydrogel material can be used as a good adsorbent for dyes, which is promising in wastewater treatment.

Pre-administration of rats with Helicobacter pylori γ-glutamyl-transpeptidase alleviates osteoarthritis.

OBJECTIVE: To determine the efficacy of Helicobacter pylori γ-glutamyl-transpeptidase (GGT) in osteoarthritis (OA) therapy. RESULTS: Oral administration of rats with rGGT alleviated joint pain in the acute phase of iodoacetate (IA)-induced OA. The CXCL1/IL-6 in blood and in articular tissue as well as circulating granulocytes in the recipients of GGT, were reduced. This might be associated with the expansion of regulatory T cells in the inguinal lymph nodes and increased articular IL-10. CONCLUSION: We provide preclinical evidence that H. pylori GGT may represent a promising candidate for OA therapy.

Cordycepin protected against the TNF-α-induced inhibition of osteogenic differentiation of human adipose-derived mesenchymal stem cells.

Cordycepin, 3'-deoxyadenosine, is an effective component isolated from the rare Chinese caterpillar fungus Cordyceps militaris. It exerts potent anti-inflammatory actions in different cell and animal models. However, its action remains unclear on the TNF-α-induced inhibition of osteogenic differentiation of adipose-derived mesenchymal stem cells (ADMSCs). In the present study, we demonstrated that cordycepin induced cell death at 20 and 40 µg/mL. Interestingly, 10 µg/mL cordycepin abrogated the cell death induced by 20 ng/mL TNF-α. Meanwhile, cordycepin exhibited a dose-dependent regulation of the osteogenesis of human ADMSCs: it promoted the differentiation at 10 µg/mL, whereas inhibited differentiation at 40 µg/mL. Furthermore, we discovered that 10 µg/mL cordycepin protected against the TNF-α (induced inhibition of osteogenic differentiation of human ADMSCs. It was also revealed that 10 µg/mL cordycepin restored Runx2 and Osx mRNA levels, which were significantly inhibited by TNF-αduring osteogenesis. At the same time, we found that 10 µg/mL cordycepin suppressed TNF-α-activated NF-κB signaling, by inhibiting IκBα phosphorylation and subsequent p65 release and translocation into the cell nucleus. Of clinical interest, the present study revealed mechanisms involved in inflammatory cytokine-inhibited osteogenesis, and it highlights the potential of cordycepin to promote the osteogenesis of human ADMSCs in cell-based therapy for inflammatory bone diseases.

MRI analysis of the ISOBAR TTL internal fixation system for the dynamic fixation of intervertebral discs: a comparison with rigid internal fixation.

OBJECTIVES: Using magnetic resonance imaging (MRI), we analyzed the efficacy of the posterior approach lumbar ISOBAR TTL internal fixation system for the dynamic fixation of intervertebral discs, with particular emphasis on its effects on degenerative intervertebral disc disease. METHODS: We retrospectively compared the MRIs of 54 patients who had previously undergone either rigid internal fixation of the lumbar spine or ISOBAR TTL dynamic fixation for the treatment of lumbar spondylolisthesis. All patients had received preoperative and 6-, 12-, and 24-month postoperative MRI scans of the lumbar spine with acquisition of both routine and diffusion-weighted images (DWI). The upper-segment discs of the fusion were subjected to Pfirrmann grading, and the lumbar intervertebral discs in the DWI sagittal plane were manually drawn; the apparent diffusion coefficient (ADC) value was measured. RESULTS: ADC values in the ISOBAR TTL dynamic fixation group measured at the 6-, 12-, and 24-month postoperative MRI studies were increased compared to the preoperative ADC values. The ADC values in the ISOBAR TTL dynamic fixation group at 24 months postoperatively were significantly different from the preoperative values (P < 0.05). At 24 months, the postoperative ADC values were significantly different between the rigid fixation group and the ISOBAR TTL dynamic fixation group (P < 0.05). CONCLUSION: MRI imaging findings indicated that the posterior approach lumbar ISOBAR TTL internal fixation system can prevent or delay the degeneration of intervertebral discs.