Tough Engineering Hydrogels Based on Swelling-Freeze-Thaw Method for Artificial Cartilage.

Articular cartilage, which exhibits toughness and ultralow friction even under high squeezing pressures, plays an important role in the daily movement of joints. However, joint soft tissue lesions or injuries caused by diseases, trauma, or human functional decline are inevitable. Poly(vinyl alcohol) (PVA) hydrogels, which have a water content and compressive strength similar to those of many tissues and organs, have the potential to replace tough connective tissues, including cartilage. However, currently, PVA hydrogels are not suitable for complex dynamic environments and lack rebound resilience, especially under long-term or multicycle mechanical loads. Inspired by biological tissues that exhibit increased mechanical strength after swelling, we report a tough engineered hydrogel (TEHy) fabricated by swelling and freeze-thaw methods with a high compressive strength (31 MPa), high toughness (1.17 MJ m-3), a low friction coefficient (0.01), and a low energy loss factor (0.22). Notably, the TEHy remained remarkably resilient after 100 000 cycles of contact extrusion and remains intact after being compressed by an automobile with a weight of approximately 1600 kg. The TEHy also exhibited excellent water swelling resistance (volume and weight changes less than 5%). Moreover, skeletal muscle cells were able to readily attach and proliferate on the surface of TEHy-6, suggesting its outstanding biocompatibility. Overall, this swelling and freeze-thaw strategy solves the antifatigue and stability problems of PVA hydrogels under large static loads (>10 000 N) and provides an avenue to fabricate engineering hydrogels with strong antifatigue and antiswelling properties and ultralow friction for potential use as biomaterials in tissue engineering.

Boosting transfection efficiency: A systematic study using layer-by-layer based gene delivery platform.

Nowadays, the nanoparticle-based delivery approach is becoming more and more attractive in gene therapy due to its low toxicity and immunogenicity, sufficient packaging capacity, targeting, and straightforward, low-cost, large-scale good manufacturing practice (GMP) production. A number of research works focusing on multilayer structures have explored different factors and parameters that can affect the delivery efficiency of pDNA. However, there are no systematic studies on the performance of these structures for enhanced gene delivery regarding the gene loading methods, the use of additional organic components and cell/particle incubation conditions. Here, we conducted a detailed analysis of different parameters such as (i) strategy for loading pDNA into carriers, (ii) incorporating both pDNA and organic additives within one carrier and (iii) variation of cell/particle incubation conditions, to evaluate their influence on the efficiency of pDNA delivery with multilayer structures consisting of inorganic cores and polymer layers. Our results reveal that an appropriate combination of all these parameters leads to the development of optimized protocols for high transfection efficiency, compared to the non-optimized process (> 70% vs. < 7%), and shows a good safety profile. In conclusion, we provide the proof-of-principle that these multilayer structures with the developed parameters are a promising non-viral platform for an efficient delivery of nucleic acids.

Therapeutic potential of vanadium complexes with 1,10-phenanthroline ligands, quo vadis? Fate of complexes in cell media and cancer cells.

VIVO-complexes formulated as [VIVO(OSO3)(phen)2] (1) (phen = 1,10-phenanthroline), [VIVO(OSO3)(Me2phen)2] (2) (Me2phen = 4,7-dimethyl-1,10-phenanthroline) and [VIVO(OSO3)(amphen)2] (3) (amphen = 5-amino-1,10-phenanthroline) were prepared and stability in cell incubation media evaluated. Their cytotoxicity was determined against the A2780 (ovarian), MCF7 (breast) and PC3 (prostate) human cancer cells at different incubation times. While at 3 and 24 h the cytotoxicity differs for complexes and corresponding free ligands, at 72 h incubation all compounds are equally active presenting low IC50 values. Upon incubation of A2780 cells with 1-3, cellular distribution of vanadium in cytosol, membranes, nucleus and cytoskeleton, indicate that the uptake of V is low, particularly for 1, and that the uptake pattern depends on the ligand. Nuclear microscopic techniques are used for imaging and elemental quantification in whole PC3 cells incubated with 1. Once complexes are added to cell culture media, they decompose, and with time most VIV oxidizes to VV-species. Modeling of speciation when [VIVO(OSO3)(phen)2] (1) is added to cell media is presented. At lower concentrations of 1, VIVO- and phen-containing species are mainly bound to bovine serum albumin, while at higher concentrations [VIVO(phen)n]2+-complexes become relevant, being predicted that the species taken up and mechanisms of action operating depend on the total concentration of complex. This study emphasizes that for these VIVO-systems, and probably for many others involving oxidovanadium or other labile metal complexes, it is not possible to identify active species or propose mechanisms of cytotoxic action without evaluating speciation occurring in cell media.

The Control of Glucose and Lactate Levels in Nutrient Medium After Cell Incubation and in Microdialysates of Human Adipose Tissue by Capillary Electrophoresis with Contactless Conductivity Detection.

Two methods of capillary electrophoresis with contactless conductivity detection have been developed for monitoring the levels of glucose and lactate in clinical samples. The separations are performed in uncoated fused silica capillaries with inner diameter 10 or 20 µm, total length 31.5 cm, length to detector 18 cm, using an Agilent electrophoretic instrument with an integrated contactless conductivity detector. Glucose is determined in optimized background electrolyte, 50 mM NaOH with pH 12.6 and 2-deoxyglucose is used as an internal standard; the determination of lactate is performed in 40 mM CHES/NaOH with pH 9.4 and lithium cations as an internal standard. Both substances are determined in minimal volumes of (1) nutrient media after cell incubation, and (2) microdialysates of human adipose tissue; after dilution and filtration as the only treatment of the sample. The migration time of glucose is 2.5 min and that of lactate is 1.5 min with detection limits at the micromolar concentration level. The developed techniques are suitable for sequential monitoring of glucose and lactate over time during metabolic experiments.

The method of isolation,culture and identification of primary human endometrial cells / 重庆医学

Objective To study the isolation method and the culture method of primary human endometrial cells and to iden‐tify the purity and biological activity .Methods We digested human endometrial tissue by collagenase at first ,and then to separate , purify and culture the human glandular stromal cells(ESC) and endometrial epithelial cells(EEC)by differential centrifugation ,dab‐ble screen filtration and adhesion purification technology .Ultimately ,we identified the isolated cells with cytokeratin and vimentin immunocytochemical staining and immunofluorescence method .Results Stromal cells showed a parallel growth .The cells were spindle or polygonal ,and the vimentin antibody showed a positive immunohistochemical staining ,the purity was more than 95% .At the same time ,glandular epithelial cells grew in whorls .The cells were polygonal or tadpole shaped ,and the cytokeratin antibody immunohistochemical staining ,the purity were up to 90% .Conclusion The successful isolation and culture of high quantity ,viabili‐ty and purity by collagenase digestion and dabble screen filter method of endometriall cells make a strong operability .The laboratory which has the basic cell culture conditions can develop the experiment .

Research on combinative effect of methotrexate and caffeine on osteosarcoma cell line / 中国矫形外科杂志

[Objective]To observe whether or not caffeine can improve the cyto-toxicity effect of methotrexate(MTX) on osteosarcoma cell line.[Method]Osteosarcoma cell(OS-732)were incubated with no drug,caffeine,MTX or MTX adding caffeine separately,and were named as control group,caffeine group,MTX group and mixing group respectively.The ratios of cells on G2M phase of each group were measured with flow cytometry after 48 h incubation and the cell inhibition ratios were measured with the MTT colorimetric analysis after 72 h incubation.[Result]The ratios(%)of cells on G2M phase were control group(23.210?0.416),caffeine group(23.120?0.440),MTX group(28.770?0.531)and mixing group(0.105?0.002)(P

Isolation,incubation and identification of parenchymal neural stem cells in adult mouse spinal cord / 中华创伤杂志

Objective To isolate and identify the adult neural stem cells from the parenchyma of spinal cord in adult mouse.Methods The parenchymal spinal cord from adult mouse was dissected and dissociated by mechanical trituration.The tissue suspension was cultured in serum-free DMEM/F12 medium supplemented with EGF and B27.The cell colonies generated from a single cell were screened by limited dilution and incubated with BrdU.The cell colonies were transferred into medium with serum to induce differentiation.The cells were identified with antibodies to Nestin,BrdU,MAP2 and GFAP by immunofluorescence staining.Results The cells were cultured for seven days to generate proliferative neurospheres.The majority of cells in these neurospheres expressed Nestin and were differentiated into MAP2-positive cells and GFAP-positive cells in medium containing with fetal bovine serum.Conclusion A significant number of neural stem cells are present in the parenchymal adult mouse spinal cord and can proliferate and also give rise to neurons and glia in vitro.