Artificial cells, blood substitutes, and immobilization biotechnology最新文献

To investigate whether polymerized human placenta hemoglobin (PolyPHb) improved hemodynamic parameter recovery and cardiac function after hemorrhagic shock, a mean arterial pressure (MAP) of 30 mmHg was maintained for 60min. Then, all the rats were randomly resuscitated with hetastarch (HES), shed blood (Whole Blood), or PolyPHb (PolyPHb). The MAP was greatly improved by PolyPHb, but it was still lower than that of the Whole Blood group. Meanwhile, the cardiac function and enzyme releases in the PolyPHb group were similar to the HES group. Therefore, our findings suggest that PolyPHb moderately improved hemodynamic recovery and provided little cardioprotective effect in hemorrhagic shock.

A new amperometric biosensor was developed for determining hypoxanthine in fish meat. Xanthine oxidase with pyrrole and polyvinylsulphonate was immobilized on the surface of a platinum electrode by electropolymerization. The determination of xanthine-hypoxanthine was performed by means of oxidation of uric acid liberated during the enzyme reaction on the surface of the enzyme electrode at + 0.30V (SCE). The effects of pH, substrate concentration, and temperature on the response of the xanthine-hypoxanthine biosensor were investigated. The linear working range of the enzyme electrode was 1.0 × 10(-7) -1.0 × 10(-3) M of the hypoxanthine concentration, and the detection limit was 1.0 × 10(-7)M. The apparent K(m(app)) and I(max) of the immobilized xanthine oxidase were found to be 0.0154 mM and 1.203 μA/mM, respectively. The best pH and temperature value for xanthine oxidase were selected as 7.75 and 25°C, respectively. The sensor was used for the determination of hypoxhantine in fish meat. Results show that the fish degraded very rapidly after seven days and the hypoxanthine amount was found to increase over days of storage.

Oral tissue engineering aims to treat and fill tissue deficits caused by congenital defects, facial trauma, or malignant lesion surgery, as well as to study the biology of oral mucosa. The Food and Drug Administration (FDA) and the European Medicines Agency (EMA) require a large animal model to evaluate cell-based devices, including tissue-engineered oral mucosa, prior to initiating human clinical studies. Porcine oral mucosa is non-keratinized and resembles that of humans more closely than any other animal in terms of structure and composition; however, there have not been any reports on the reconstruction of a porcine oral mucosa equivalent, probably due to the difficulty to culture porcine fibroblasts. In this study, we demonstrate the feasibility of a 3D porcine oral mucosa equivalent based on a collagen-GAG-chitosan scaffold, as well as reconstructed porcine epithelium by using an amniotic membrane as support, or without any support in form of epithelial cell sheets by using thermoresponsive culture plates. Explants technique was used for the isolation of the porcine fibroblasts and a modified fibroblast medium containing 20% fetal calf serum was used for their culture. The histological and transmission electron microscopic analyses of the resulting porcine oral mucosa models showed the presence of non-keratinized epithelia expressing keratin 13, the major differentiation marker of non-keratinized oral mucosa, in all models, and the presence of newly synthesized collagen fibers in the lamina propria equivalent of the full-thickness model, indicating the functionality of porcine fibroblasts.

In this paper, a novel amperometric choline biosensor with immobilization of choline oxidase on electrochemically polymerized polypyrrole-polyvinylsulphonate (PPy-PVS) film has been accomplished via the entrapment technique. The effects of pH and temperature were investigated and optimum parameters were found to be 9.0 and 60 °C, respectively. There are two linear parts in the region between 1.0 × 10 (-7) - 1.0 × 10 (-6)M (R(2) = 0.997) and 1.0 × 10 (-5) - 1.0 × 10 (-3) M (R(2) = 0.986). The storage stability and operation stability of the enzyme electrode were also studied.

In the present study, the stabilizing effect of dextrans as additives on the denaturation and inactivation of glucose oxidase (GOD) was investigated. Three different molecular weighted dextrans (M(w) 17.5, 75, 188 kD) were used with different concentrations. Dramatically increased enzyme activities were measured after one hour of incubation of enzyme with additives between 25-40°C in water bath. Highest activity value was measured with 75 kDa molecular weighted dextran (in concentration 30% w/v) at pH 5. Dextran as an additive supplied a long shelf-life to the enzyme at 4°C. In the presence of the 75 kDa dextran, the enzyme was more stable and its activity was increased 2.7-fold at 30°C. In addition, dextran protected GOD against inactivation by a n-heptane/aqueous buffer-stirred system.

Objective: To evaluate whether garlicin can attenuate reperfusion no-reflow in a catheter-based porcine model of acute myocardial infarction (AMI).

Methods: Twenty-two swine were used: six in a sham-operation group, and eight each in the control and garlicin groups. The distal part of the left anterior descending coronary artery (LAD) in the latter two groups was occluded by a dilated balloon for 2 hr, then reperfused for 3 hr. Garlicin (1.88mg/kg) was injected just before reperfusion until reperfusion for 1 hr in the garlicin group. Hemodynamic data were examined before AMI, 2 hr after occlusion, and 3 hr after reperfusion. Myocardial contrast echocardiography (MCE) and pathological staining were performed to evaluate the myocardial no-reflow area (NRA). Serum proinflammatory cytokines and endothelin (ET)-1 were examined by radioimmunoassay.

Results: Left ventricular systolic pressure (LVSP) and left ventricular end-diastolic pressure (LVEDP) significantly improved in the garlicin group after reperfusion compared with the control group and also 2hr after AMI (p<0.05 for both). MCE and pathological staining both showed garlicin attenuated reperfusion NRA after AMI (p<0.05, p<0.01). Garlicin not only decreased serum interleukin (IL)-6 and tumor necrosis factor (TNF)-α after reperfusion (p<0.05 for both), but also ET-1 level (p<0.01).

Conclusion: Garlicin attenuated reperfusion no-reflow in our catheter-based porcrine model of AMI, possibly through decreasing serum proinflammatory cytokines and ET-1.

This study aims to examine the contribution of PEG-conjugated hemoglobin combined with cisplatin to the expression of HIF-1α and MDR1 in a tumor xenograft model. Cervical carcinoma models were assigned to 4 groups and treated respectively: group 1(control); group 2, cisplatin; group 3, PEG-Hb; group 4 cisplatin plus PEG-Hb. 4 weeks later, tumor volume and MVD was significantly decreased in group 4 compared with other groups. Lower expression of HIF-1α and MDR1 were detected in group4. Taken together, our data indicated that PEG-Hb plus cisplatin can promote tumor tissue oxygenation and enhance the chemotherapy sensitivity. HIF-1α regulated MDR1 pathway correlated with this process.

The first experimental artificial red blood cells have all three major functions of red blood cells (rbc). However, the first practical one is a simple polyhemoglobin (PolyHb) that only has an oxygen-carrying function. This is now in routine clinical use in South Africa and Russia. An oxygen carrier with antioxidant functions, PolyHb-catalase-superoxide dismutase, can fulfill two of the three functions of rbc. Even more complete is one with all three functions of rbc in the form of PolyHb-catalase-superoxide dismutase-carbonic anhydrase. The most advanced ones are nanodimension artificial rbc with either PEG-lipid membrane or PEG-PLA polymer membrane. Extensions into oxygen therapeutics include a PolyHb-tyrosinase that suppresses the growth of melanoma in a mice model. Another is a PolyHb-fibrinogen that is an oxygen carrier with platelet-like function. Research has now extended well beyond the original research on artificial rbc into many areas of artificial cells. These include nanoparticles, nanotubules, lipid vesicles, liposomes, polymer-tethered lipid vesicles, polymersomes, microcapsules, bioencapsulation, nanocapules, macroencapsulation, synthetic cells, and others. These are being used in nanotechnology, nanomedicine, regenerative medicine, enzyme/gene therapy, cell/stem cell therapy, biotechnology, drug delivery, hemoperfusion, nanosensers, and even by some groups in agriculture, industry, aquatic culture, nanocomputers, and nanorobotics.

We investigated the neuroprotective effects of Rg(2) in anoxic cultured hippocampal neurons of newborn rats. The cells were divided into a control group, nimodipine group (5 μmol/L), Rg(2) (0.025 mmol/L), and Rg(2) (0.05 mmol/L) group. The apoptosis rate of hippocampal neurons was measured by flow cytometry with staining of PI. The intracellular calcium ion [Ca(2+)]i was observed with fluorospectrophotometer determined by fluorescent probe Fluo-2/AM. The contents of MDA and NO and the activities of SOD in the supernatants of cells were determined by biochemical methods. The results demonstrated that Rg(2) reduced the hypoxia-induced apoptosis, decreased the calcium overload in neurons, increased the activities of SOD, and decreased the contents of MDA and NO in the supernatants of cells. Our study suggests that Rg(2) has a neuroprotective effect against hypoxia-induced neuronal damage in hippocampal neurons mediated by anti-apoptosis, blocking calcium over-influx into neuronal cells, eliminating the free radicals, and increasing the activities of anti-oxidative enzymes to inhibit the oxidative damages caused by anoxic.

With advances in technical methodology, the grafting of biocompatible conduits may become a viable alternative for the reconstruction of nerve gaps. In this study, electrospinning was used to fabricate nerve conduits (NCs) from poly(L-lactide-coglycolide)-silk fibroin. Conduits or autograft nerves were employed to bridge 10 mm defects in the sciatic nerves of Sprague-Dawley rats. Six weeks after the operation, morphological and functional assessment showed that nerve conduits from PLGA-silk fibroin grafts promoted the regeneration of peripheral nerves. The effects were similar to those obtained using nerve autografts. This method offers a promising alternative to the use of nerve autografts.