Construction of controllable polyethylene glycol bioactive coating with hemocompatibility from the surface of modified glass substrate / 生物医学工程学杂志

A diblock copolymer, poly(ethylene glycol) methacrylate-block-glycidyl methacrylate (PEGMA-GMA), was prepared on glass substrate by surface-initiated atom transfer radical polymerization (SI-ATRP), and endothelial specific peptide Arg-Glu-Asp-Val (REDV) was immobilized at the end of the PEGMA-GMA polymer brush by ring opening reaction through the rich epoxy groups in the GMA. The structure and hydrophilicity of the polymer brushes were characterized by static water contact angle, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The results showed that the REDV modified copolymer brushes were successfully constructed on the glass substrates. The REDV peptide immobilized onto surface was quantitatively characterized by ultraviolet-visible spectroscopy (UV-VIS). The blood compatibility of the coating was characterized by recalcification time and platelet adhesion assay. The results showed that the polymer coating had good blood compatibility. The multifunctional active polymer coating with PEGMA and peptide produced an excellent prospect in surface construction with endothelial cells selectivity.

Inhibiting Smooth Muscle Cell Proliferation via Immobilization of Heparin/Fibronectin Complexes on Titanium Surfaces / 生物医学与环境科学（英文）

The aim of this study was to investigate the inhibitory effect of heparin/fibronectin (Hep/Fn) complexes on neointimal hyperplasia following endovascular intervention. Hep/Fn complexes were immobilized onto titanium (Ti) surfaces, with subsequent X-ray photoelectron spectroscopy (XPS), Toluidine Blue O (TBO) and immunohistochemistry methods were used to characterize surface properties. Smooth muscle cell (SMC) cultures were used to evaluate the effect of Hep/Fn complexes on SMC proliferation. Results showed that Hep/Fn complexes successfully immobilized onto Ti surfaces and resulted in an inhibition of SMC proliferation. This study suggests that Hep/Fn surface-immobilized biomaterials develop as a new generation of biomaterials to prevent neointimal hyperplasia, particularly for use in cardiovascular implants.

Development of a method for methylated DNA enrichment with functionalized mesocellular silica foams immobilized with methyl CpG binding domain / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To develop a method for enriching methylated DNA in clinical samples using mesocellular silica foams (MCFs) immobilized with methyl-CpG binding domain (MBD).</p><p><b>METHODS</b>MCFs with ultra-large pore size were synthesized, functionalized and immobilized with GST-MBD.</p><p><b>RESULTS</b>The large cage-like pore structures of MCF materials was retained after functionalization and immobilization, with pore diameter of 55 nm, window size of 30 nm, and a high pore volume of 1.0 cm(3)/g. The loading amount of MBD was as high as 53 wt%. Immobilized MBD showed high binding activity and stability. In a binding buffer with salt concentrations ranging 500-550 mmol/L, the MCF-MBD can selectively enrich methylated DNA from the mixed DNA solution.</p><p><b>CONCLUSION</b>The MCF-MBD method may offer a better choice for high-throughout DNA methylation screening, and has laid a foundation for clinical application, prenatal diagnosis and research on DNA methylation-related genetic diseases.</p>

A novel immunotherapy for superficial bladder cancer by the immobilization of streptavidin-tagged bioactive IL-2 on the biotinylated mucosal surface of the bladder wall / 癌症

<p><b>BACKGROUND AND OBJECTIVE</b>Intravesical administration of Bacillus Calmette-Guerin (BCG) after transurethral resection is by far the most effective local therapy for superficial bladder cancer, the fifth most common cancer in the world. However, approximately one-third of patients fail to respond and most patients eventually relapse. In addition, there are pronounced side effects of BCG therapy, such as BCG sepsis and a high frequency of BCG-induced cystitis. This study established a novel immunotherapy through immobilization of streptavidin-tagged human IL-2 (SA-hIL-2) on the biotinylated mucosal surface of bladder wall.</p><p><b>METHODS</b>A mouse orthotopic model of MB49 bladder cancer was established by perfusing MB49 cells into mouse bladders. The SA-hIL-2 fusion protein was immobilized on the biotinylated mucosal surface of the bladder wall. Treatment began on day 1 after MB49 implantation, once every 3 days for 6 times. Immunohistochemical assay was performed to assess the persistence of SA-hIL-2 immobilized on the biotinylated mucosal surface of the bladder wall. The mice were monitored for tumor growth and survival. On day 60 after MB49 implantation, the SA-hIL-2-cured mice, which were found to have no hematuria or palpable tumors, were challenged with wild-type MB49 cells implanted into the pretreated bladder and monitored for survival.</p><p><b>RESULTS</b>SA-hIL-2 could be immobilized efficiently and durably on the bladder mucosal surface as long as 7 days. On day 60 after MB49 implantation, 9 out of 20 SA-hIL-2-treated mice survived, but all mice in PBS control group died. More importantly, 5 out of 9 tumor-free mice in the SA-hIL-2 group were protected against a second intravesical wild-type MB49 tumor challenge.</p><p><b>CONCLUSIONS</b>SA-hIL-2 fusion protein could significantly inhibit tumor growth and extend the survival time in the orthotopic model of MB49 bladder cancer.</p>

Immobilization of streptavidin-tagged bioactive hTNF-alpha on biotinylated mucosal surface of the bladder wall for treatment of superficial bladder cancer in mice / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate a novel immunotherapy through immobilization of streptavidin-tagged hTNF-alpha on the biotinylated mucosal surface of the bladder wall for bladder cancer treatment in mice.</p><p><b>METHODS</b>A total of 120 female C57BL/6j mice were randomized into 5 equal groups, namely blank control, PBS, soluble hTNF-alpha, SA-GFP, and SA-hTNF-alpha treatment groups. Twenty-four hours after establishment of a mouse model of orthotopic superficial bladder cancer, SA-hTNF-alpha fusion protein was immobilized on the biotinylated mucosal surface of the bladder wall, which was repeated every 4 days for a total of 6 sessions. Immunohistochemistry was performed to detect the retention time of SA-hTNF-alpha fusion protein in the biotinylated mouse bladder mucosa and the distribution of CD4(+) and CD8(+) lymphocytes in the mucosa and tumor tissues, with the tumor growth and mouse survival also observed. The cytotoxiciy of the tumor-specific lymphocytes was evaluated. The mice responding well to the treatment were re-challenged by MB49 and monitored for survival.</p><p><b>RESULTS</b>SA-hTNF-alpha could be efficiently and stably immobilized on the bladder mucosal surface for as long as 7 days. On day 60 after MB49 implantation, 18 out of 22 SA- hTNF-alpha-treated mice survived, with 9 appearing tumor-free, but all the mice in PBS control group died. Five out of 9 tumor-free mice in SA-hTNF-alpha group showed resistance to a re-challenge with intravesical MB49. The numbers of CD4(+) and CD8(+) lymphocytes were significantly greater in SA-hTNF-alpha group than in the other groups (P<0.05). The cytotoxicity of the tumor-specific lymphocytes was significantly stronger in SA-hTNF-alpha group than in the other groups (P<0.05).</p><p><b>CONCLUSION</b>SA-hTNF-alpha immobilized on the biotinylated mucosal surface of the bladder wall can significantly inhibit the tumor growth and promote the survival of the mice bearing orthotopic superficial bladder cancer.</p>

Up-regulation of Fas is related to apoptosis of HeLa cells induced by co-immobilized TNF-alpha/IFN-gamma / 生物医学工程学杂志

This study was aimed to examine the expression of apoptosis-associated gene Fas in HeLa cell, explore the effects of the co-immobilized cytokines (tumor necrosis factor-alpha and interferon-gamma), and probe the potential mechanism of action. The preparation and application of the research couple IFN-gamma and TNF-alpha to the polystyrene cell culture plate were performed using the Photo-immobilization method, with different doses (20 ng/well and 200 ng/well) and synthesized optical active material. HeLa cells were treated with cytokines for two dose and 1, 3, 6 days. The result showed that the free cytokines induced HeLa apoptosis quickly, yet the HeLa apoptosis induced by co-immobilized cytokines had longer effect.

The effect of co-immobilized TNF-alpha/IFN-gamma on mitochondrial membrane potential of HeLa cells / 生物医学工程学杂志

This study inquired into the mechanisms of co-immobilized cytokines and free cytokines-induced apoptosis on HeLa cells. With the use of photochemical fixed method, TNF-alpha/IFN-gamma were co-immobilized on a 24-well polystyrene culture plate. HeLa cells were stained with fluorescent probe JC-1 to detect the changes of mitochondrial membrane potential (deltapsim), and then were examined by flow cytometry. The results showed that co-immobilized cytokines could induce the apoptosis of HeLa cells in a dose-independent manner. When treated with low-dose of co-immobilized cytokines (20ng/ml), the mitochondrial membrane potential (deltapsim) of HeLa cells continually decreased in 6 days. These indicate that low dose co-immobilized cytokines have a long-term of apoptosis-inducing effect on HeLa cells. We assume that there is close relationship between the mitochondrial membrane potential decrease and the apoptosis of HeLa cells.

The effect of immobilized laminin on titanium-oxide films to the behavior of human umbilical vein endothelial cells / 生物医学工程学杂志

In this study, Ti-O films were synthesized using magnetron sputtering, and were pretreated using NaOH solution for improving surface activity from hydroxyl. The laminin(LN) biomacromolecule was further immobilized to the surface through an anminosilane linker. The surface characteristics of these samples were analyzed by Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, Atomic Force Microscopy and the contact angle method. Finally, human umbilical vein endothelial cells (HUVEC) were in vitro seeded to the modified and unmodified Ti-O films surface for evaluating the cell compatibility. Survey results suggested that the functional group of hydroxyl was presented onto Ti-O film surface after being pretreated, and laminin could be covalently immobilized to Ti-O film surface by anminosilane linker. The in vitro cell culture results reveal that the biological behaviors of ECs on biochemical modified Ti-O film surface are excellent. The adherence, growth and proliferation of ECs on laminin-immobilized surface were obviously improved when compared to control one. It implies that the laminin immobilizing is helpful to increasing the endothelialization of Ti-O films.

Expression of Bax, Bcl-2 and P53 in the HeLa apoptosis induced by co-immobilized cytokines / 生物医学工程学杂志

The aim of this study was to evaluate the changes in the expression of Bax, Bcl-2 and P53 when HeLa cells were induced by free cytokines or co-immobilized cytokines. The cells were induced for 24 hrs,72 hrs, 120 hrs and 168 hrs. Then, the expression of Bax, Bcl-2 and P53 was observed by immunohistochemistry. The average optic density of reaction products was tested by image analysis. Lastly, data were analyzed statistically. After the HeLa cells were induced for 120 hrs, the average optic denisity of Bcl-2 was much decreased. However, the average optic Bax was much increased. The average optic density of P53 also increased with the increase of time. The results suggest that HeLa apoptosis was induced by tumor necrosis factor-a and interferon -gamma, and the increasing expression of P53 may induce the expression of Bax and prevent the expression of Bcl-2, via the mitochondrial induction of cell apoptosis.

HeLa apoptosis induced by co-immobilized cytokines / 生物医学工程学杂志

IFN-gamma and TNF-alpha were co-coupled to the polystyrene cell culture plate by the photo-immobilization method. To investigate the synergistic effect of IFN-gamma and TNF-alpha on the HeLa cells, HeLa cells were treated with co-coupled cytokine or non-coupled cytokine in a time course in this study. The morphology detection, cell cycle analysis by flow cytometry, phosphatidyl serine analysis and capase-3 activity detection demonstrated that the two kinds of treatments both induce HeLa cells apoptosis. Non-coupled cytokine worked more quickly while co-coupled cytokine kept more permanent effect. The caspase-3 activity assay indicated that the caspase-3 activity of HeLa cells treated with non-coupled cytokine is higher than that of HeLa cells treated with co-coupled cytokine. This may imply that co-coupled cytokine not only induces the caspase-dependent pathway, but also induces the caspase-independent pathway.