Objective:A mineralized gelatin methacryloyl/hyaluronic acid methacryloyl (GelMA/HAMA) double network hydrogel was constructed, its performance was characterized, and its cell compatibility was studied.Methods:The hydrogel was constructed by photocrosslinking technology, and the biomimetic mineralized hydrogel was prepared by alternating mineralization with calcium and phosphorus solution. The hydrogel was mineralized for three times, for 24 h each time. The control groups were the non-mineralized groups, named the GelMA-0 group and GelMA/HAMA-0 group, respectively. The experimental groups were the mineralized treatment groups. The GelMA hydrogel and GelMA/HAMA double network hydrogel mineralized for 1, 2 and 3 times were named the GelMA-1, 2 and 3 group and GelMA/HAMA-1, 2 and 3 group, respectively. The microstructure of the mineralized hydrogel was characterized by scanning electron microscope and energy dispersive X-ray spectroscopy. The chemical composition of the mineralized hydrogel was characterized by Fourier transform infrared spectroscopy and X-ray diffraction. The mineralization rate of the mineralized hydrogel was evaluated by the ashing method. The compressive strength of the mineralized hydrogel was evaluated by a compression test. The cell compatibility of bone marrow mesenchymal stem cells (BMSCs) on the mineralized hydrogel surface was evaluated by a cell counting kit-8 assay and living/dead cell staining experiment. The datas were analyzed by one-way analysis of variance and Tukey test.Results:With the increase in the number of mineralization cycles, the mineralized layer gradually thickened, and the mineral layer on the cross section of the hydrogel uniformly penetrated into the interior of the hydrogel, with the amount of internal mineral deposition increased. The microstructure of the hydrogel and the distribution of inorganic particles also changed. The surface of the GelMA-3 group and the GelMA/HAMA-3 group contained Ca and P elements, and the distribution was consistent. The inorganic particles generated by mineralization may be immature hydroxyapatite (HAP) crystal precursors. To further verify the chemical composition of inorganic particles, the GelMA-0 and 3 groups as well as the GelMA/HAMA-0 and 3 groups of hydrogels showed GelMA amide Ⅰ, Ⅱ and Ⅲ bands. The GelMA-3 group and GelMA/HAMA-3 group hydrogels contained phosphate, and the diffraction peaks confirmed that the inorganic particles are mainly HAP crystal precursors with low crystallinity. The mineralization rates of the GelMA-1, 2 and 3 groups were (12.48±1.06)%, (21.12±0.62)% and (27.31±0.45)%, while those of the GelMA/HAMA-1, 2 and 3 groups were (15.54±1.03)%, (23.39±0.25)% and (32.26±0.62)%, and the compressive elastic modulus of the GelMA-0, 1, 2 and 3 groups were (69.01±1.04, 91.76±2.05, 105.16±2.95, 131.65±2.21) kPa, and those of the GelMA/HAMA-0, 1, 2 and 3 groups were (270.76±4.56, 347.47±4.60, 388.98±6.96, 430.6±15.47) kPa. Under the same cyclic mineralization times, the mineralization rates and compressive elastic modulus of the GelMA/HAMA double network hydrogel were significantly higher than those of the GelMA hydrogel (all P<0.01). The cell proliferation rates of BMSCs on the GelMA/HAMA-0, 1, 2 and 3 hydrogel surfaces were (49.80±3.38)%, (52.32±1.28)%, (58.00±4.64)% and (62.46±2.74)% on the first day of culture, (58.86±3.36)%, (58.26±3.45)%, (73.08±2.61)% and (76.40±3.45)% on the third day of culture, and (85.89±4.23)%, (90.75±3.21)%, (103.35±4.11)% and (113.42±3.40)% on the fifth day of culture. The cell proliferation rates of the GelMA/HAMA-3 group were significantly higher than those of GelMA/HAMA-0 and 1 groups (all P<0.01). Living/dead cell staining experiment showed that BMSCs on the surface of the GelMA/HAMA-0, 1, 2 and 3 groups were dominated by living cells on the third and fifth days of culture. Conclusions:The mineralized GelMA/HAMA double network hydrogel was constructed, which significantly improved the mineralization rate, mechanical performance and cell compatibility of the biomimetic mineralized hydrogel.

In vivo, cells exist within the mechanical microenvironment of the extracellular matrix (ECM), and their biological processes are regulated by various mechanical factors. However, existing technology limits the direct study of the interaction between cells and ECM in vivo. Using hydrogel to mimic the natural ECM and to construct a suitable mechanical microenvironment for isolated cells, which indirectly reflects the cell-ECM interactions in real organisms through in vitro studies. Thus, in this review, the effects of mechanical factors in hydrogel on different types of cells were summarized, and the development of cell mechanical detection technology using hydrogel as carriers was introduced. Moreover, the future work of using hydrogel to study cell mechanical behavior and related detection technology, as well as standardized preparation, was discussed.

Dynamic hydrogel is three-dimensional networks of hydrophilic polymer formed by dynamic reversible cross-linked bonds. It is widely used in the field of bone repair therapy. The dynamic reversible cross-linked bonds in the dynamic hydrogel endows it with shear-thinning rheological properties, resulting in excellent self-healing, injectability and tunable mechanical properties. In this review, the formation mechanism of dynamic hydrogel was summarized, including non-covalent interaction and dynamic covalent interaction. The advantages and disadvantages of the various cross-linked methods used to form dynamic hydrogel were discussed. The applications of dynamic hydrogel in bone repair therapy were summarized, including haemostasis for filling bone defects, drug delivery, modulation of stem cell behavior, and biomimetic mineralization, to provide a reference for the future development of dynamic hydrogel for bone repair therapy.

Objective:To evaluate the effects of different exercises on executive function, moter skills and core symptoms in children with attention deficit hyperactivity disorder (ADHD) using network Meta-analysis, and to provide evidence-based basis for the treatment of children with ADHD.Methods:The randomized controlled trails(RCTs)of exercises on children with ADHD were searched in Web of Science, PubMed, Cochrane Library, Embase, PsycINFO, CNKI, Wanfang Data, VIP and CBM databases.The retrieval time limit was from the establishment of each database to May 2023.The Cochrane quality review manual was used to evaluate the quality of the included literatures.Stata 17.0 software was used to perform network Meta-analysis.Results:Finally, twenty-four studies were enrolled including five types of exercise intervention, such as aerobic exercise, multicomponent exercise, exergaming, high intensity interval training (HIIT) and traditional low-to-moderate intensity exercise therapy (TRAD).The results of network Meta-analysis showed that: in terms of improving executive function(working memory, inhibitory control, and cognitive flexibility), motor skills and core symptoms of children with ADHD, the optimal exercise intervention was aerobic exercises (surface under the cumulative ranking were 78.9%, 73.0%, 88.7%, 77.9% and 69.9% respectively).Conclusion:Exercises can improve executive function, improve motor skills, and alleviate ADHD core symptoms.Aerobic exercise has a better effect on improving executive function, motor skills and core symptoms of ADHD children.

Objective:To explore the application status, research hotspots and frontiers of blended teaching mode in undergraduate nursing education at home and abroad, so as to provide reference for related research.Methods:In Chinese, CNKI, Wanfang Database and VIP, and in English, Web of Science database were used as search sources. CiteSpace was used to conduct a quantitative analysis of the retrieved literatures published from 2008 to 2022.Results:A total of 43 literatures in Chinese and 83 in English were retrieved, and the number of publications showed an overall increasing trend. The research hotspots in China focused on education reform, online learning and curriculum system evaluation, and the research frontiers were network teaching, moral education and humanistic care. Foreign research focused on the choice of education model and emphasizes interaction, and the research frontier were to carry out innovative blended teaching and pay attention to the learning experience and learning environment construction of nursing students.Conclusions:In the future, blended teaching should pay attention to carrying out innovative research and dynamic evaluation and feedback of students' satisfaction. In particular, it is necessary to strengthen the cultivation of blended learning competence among nursing teachers, aiming to promote the knowledge and skills of nursing students, and continuously optimize and innovate the application of blended learning in the field of undergraduate nursing education.

Objective:To study the effects of modified citrus pectin (MCP) on the viability and gene expressions of synovial fibroblasts (SF) as well as SF treated by galectin-3 (Gal-3).Methods:Rabbit SF was isolated and cultured in vitro. Then SF was treated with different concentrations of MCP (0, 250, 500, and 750 mg/L). In addition, SF was further treated with the same different concentrations of MCP after treatment with 10 μg/ml Gal-3 for 24 h. The viability of SF was detected by CCK-8 on the first, third, and fifth day after treatment. The mRNA expression of transforming growth factor-β1 (TGF-β1), type I collagen (COL1A2), and Gal-3 in SF was detected by real-time quantitative PCR. The synthesis of type I collagen in SF was investigated by immunofluorescence staining. Results:MCP, especially at a concentration of 500 mg/L can inhibit the proliferation of SF significantly (all P < 0.05) on the first, third, and fifth day after treatment. Compared with the control group, MCP at different concentrations induced different gene expression profiles. In particular, MCP at high concentrations can upregulate the expression of TGF-β1, COL1A2 and Gal-3 in SF. However, MCP shows no significant effect on the synthesis of type I collagen in SF. MCP can down-regulate the expression of TGF-β1, COL1A2, and significantly reduce the synthesis of type I collagen in SF after Gal-3 treatment. Particularly, the effect of MCP at a concentration of 500 mg/L on inhibiting the expression of TGF-β1, COL1A2, and Gal-3 in SF is significant. Conclusions:MCP can inhibit the excessive proliferation of SF and regulate gene expression in SF.

Objective To study the application of extrusion method in inducing liposome membrane fusion or membrane component mixing,and to investigate the effect of different extrusion conditions on liposome membrane fusion rate.Methods N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) phosphatidylethanolamine (N-NBD-PE) and N-(lissamine rhodamine B sulfonyl) phosphatidylethanolamine (N-Rh-PE) labeled 1,2-dioleoyl lecithin (DOPC) liposomes and non-fluorescently labeled DOPC monolayer liposomes were mixed and extruded.The fluorescence changes before and after the extrusion of the mixed liposomes were observed using laser scanning confocal microscope,and the membrane fusion rate of the mixed liposomes was calculated by fluorescence resonance energy transfer method.Besides,the effects of extrusion times,extrusion pressure and temperature on the fusion rate of liposome membrane were studied.Results The results of laser scanning confocal microscopy showed that the distribution density and intensity of the green fluorescence of N-NBD-PE increased significantly after the extrusion of fluorescently labeled and non-fluorescent labeled DOPC liposomes,which confirmed membrane fusion.After 75 times of extrusion treatments,the liposome membrane fusion rate can reach 26％.The number of extrusions,extrusion pressure and temperature had a significant effect on the fusion rate of the liposome membrane.The higher the number of the extrusions,the smaller the extrusion pressure and the higher the efficiency of the liposome membrane fusion were at physiological temperature.Conclusions Extrusion method can induce liposome membrane fusion and membrane component mixing,and the prepared liposome has a narrower particle size distribution,which is expected to be a new method to induce the bilayer membrane fusion of liposome or lipid vesicle.

Objective To compare the diagnostic value of MRE and DWI in staging hepatic fibrosis in pa-tients with CHB. Methods In this retrospective analysis ,we investigated 93 patients with CBH and live fibrosis. Ninety-three patients were grouped according to their pathological grading of fibrosis ,from S0 to S4. Sixteen healthy patients were enrolled as the control group. Spearman correlation analysis was used to analyze the correla-tion between the stiffness and ADC value and their staging fibrosis. ROC analysis was conducted to compare the per-formance of the stiffness and ADC value in staging hepatic fibrosis. Results Both liver stiffness value(r=0.962, P<0.01)and ADC value(r=-0.823,P<0.01)were highly correlated with the stage of liver fibrosis. The area un-der ROC(AUC)for the detection of≥S1≥S2/≥S3/S4 stage fibrosis with the stiffness and ADC value were 0.963/0.868、0.995/0.947、0.998/0.948、0.996/0.889 respectively ,with statistically significant differences (P < 0.05 , resectively). Conclusions MRE and DWI have higher value ,and MRE is more accurate than DWI for staging hepatic fibrosis in patients with CHB.

Objective To construct a extracellular matrix-like collagen mimetic peptide-PEG hybrid hydrogel and to study the usage of this hydrogel in 3D culture of rabbit bone marrow mesenchymal stem cells (rBMSCs).Methods The hybrid hydrogel was synthesised by conjugating the cysteine at the end of the collagen mimetic peptide with the maleimine-modified multi-arm PEG.The circular dichroism spectra were used to characterize the triple helix structure and thermal stability of the collagen mimetic peptides.The rheology test and scanning electron microscopy were used to study the gelation process,mechanical strength and internal structure of the hydrogel.The rBMSCs were embedded in the hybrid hydrogel for 3D culture.The cell compatibility of the hydrogel and its effect on differentiation of the cells was studied.Results Collagen mimetic peptides could promote spontaneous formation of triple helix structure in the natural collagen,and the thermal transition temperature was 49.4 ℃.The formation process of the collagen mimetic peptides-PEG hybrid hydrogel was rapid,in which the porous network-like fibrous structure was formed.After the encapsulation of rBMSCs within the hydrogel for 24 h,most of the cells remained viable.Gene expression analysis showed that the hybrid hydrogel could affect the differentiation of rBMSCs.Conclusions The collagen mimetic peptide-PEG hybrid hydrogel possesses the characteristics of mild preparation condition,good mechanical strength and good cell compatibility,and is favorable to chondrocyte differentiation of rBMSCs.

BACKGROUND:Liposomes as a new drug delivery system are characterized by few adverse reactions, no immunogenicity and biodegradation. Furthermore, methotrexate-loaded liposomes can significantly reduce drug toxicity and improve anti-tumor effect. OBJECTIVE:To prepare long-circulating methotrexate-loaded liposomes and to evaluate its antitumor activity in MG-63 in vitro. METHODS:The methotrexate-loaded liposomes were prepared using the film dispersion method, and the long-circulating ones were prepared using the post-insertion method. The initial concentrations of methotrexate were 9.1, 1.82, 0.364 g/L. The ultracentrifugation method and spin column method with Sephadex G-10 or G-50 as packing were employed to separate free drugs from the methotrexate-loaded liposomes. Their recovery, size, morphology, encapsulation efficiency and drug-to-lipid ratio were evaluated. The cytotoxity of the long-circulating methotrexate-loaded liposomes purified with ultracentrifugation method and spin column G-50 method under three dose levels (0, 1, 5, 25 mg/L) were determined by MTS method. RESULTS AND CONCLUSION:According to the recovery rates of three methods, the spin column G-50 method was considered as optimal for the long-circulating methotrexate-loaded liposomes. The long-circulating liposomes were spherical or el ipsoidal under transmission electron microscope, about 200 nm in size. At the certain initial concentration of methotrexate, the encapsulation efficiency and drug-to-lipid ratio of the liposomes purified using the spin column G-50 method were remarkably higher than those purified using the other two methods. At the same mass concentration, the cytotoxity of the liposomes purified with ultracentrifugation or spin column G-50 was significantly higher than that of free methotrexate, and furthermore, the cytotoxity of the liposomes purified with spin column G-50 was higher than that of the liposomes purified with ultracentrifugation method. To conclude, the long-circulating methotrexate-loaded liposomes show a higher antitumor activity than free methotrexate in MG-63 cel s in vitro, providing the basis for further investigation of its antitumor effect on human osteosarcoma in vivo.