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

Abstract: In this paper, a novel amperometric phenol biosensor with immobilization of polyphenol oxidase (tyrosinase) on electrochemically polymerized polypyrrole-polyvinylsulphonate (PPy-PVS) film has been accomplished via the entrapment technique on the surface of a platinum electrode. The amperometric determination is based on the electrochemical reduction of quinon generated in the enzymatic reaction of phenol. The effects of pH and temperature were investigated and optimum parameters were found to be 8.0 and 30 °C, respectively. The linear working range of the electrode was 1.0 × 10(-7) - 5.0 × 10(-6) M. The storage stability and operation stability of the enzyme electrode were also studied.

Encapsulation of cells in polymeric shells allows for separation of biological material from produced factors, which may find biotechnological and biomedical applications. Human T-lymphocyte cell line Jurkat as well as rat pancreatic islets were encapsulated using LbL technique within shells of polyelectrolyte modified by incorporation of biotin complexed with avidin to improve cell coating and to create the potential ability to elicit specific biochemical responses. The coating with nano-thin modified shells allowed for maintenance of the evaluated cells' integrity and viability during the 8-day culture. The different PE impact may be observed on different biological materials. The islets exhibited lower mitochondrial activity than the Jurkat cells. Nevertheless, coating of cells with polyelectrolyte modified membrane allowed for functioning of both model cell types: 10 μm leukemia cells or 150 μm islets during the culture. Applied membranes maintained the molecular structure during the culture period. The conclusion is that applied modified membrane conformation may be recommended for coating shells for biomedical purposes.

The effects of the distal nerve degeneration on the regeneration of the collateral sprouts from the proximal nerve stump have been examined. The delayed cross-suture anastomosis technique was used in which the tibial nerve was denervated for 0-8 weeks before cross-suture of the freshly axotomized common peroneal and chronically denervated TIB nerve stumps. There was a remarkable decreasing of the regenerated myelinated axons number after the distal nerve suffered 8 weeks deterioration, suggesting that short-term denervation did not affect the collateral sprouts regeneration but more prolonged denervation profoundly reduced collateral sprouts regenerated in the distal nerve stump.

Injection of endothelial progenitor cells (EPCs) into arteries for cell therapy is a promising field in regenerative medicine. However, adhesion of EPCs during capillary passage is restricted, and non-adhering cells are lost into circulation. Here we demonstrate that it is possible to achieve a three- to sevenfold higher rate of EPC adhesion to endothelium and extracellular matrix molecules after short-term activation with phorbol myristate acetate (PMA). In addition, differentiation and toxicity analyses of PMA activated EPCs showed no impact on cell differentiation and negligible impact on cell survival.

This study aimed to compare the fixation stability of a new device (SCCAB) for femoral neck fractures and the cancellous lag screws. Standardized femoral neck osteotomies were created in seven pairs of cadaver femurs and stabilized with either SCCAB or cancellous lag screws. The specimens were subjected to incremental axial loading to 1300 N and cyclic loading at 1300 N for 104 cycles. No significant differences in downward femoral head displacement, change in the superior osteotomy gapping, and load to failure were observed between the two groups. SCCAB may be potentially useful to treat femoral neck fractures.

Lipase from Candida rugosa (CRL) was immobilized by physical adsorption onto Al(2)O(3). The immobilization yield was more than 95% during 30 min. The properties of free and immobilized enzyme were also searched and compared. The optimum pH was shifted from 7 to 8.5 by immobilization of the enzyme. The maximum activity of the free and the immobilized enzymes occured at 35 and 40°C, respectively.

Sodium nitrite (NaNO(2)) was evaluated in a 55% EBV hemorrhage swine model to mitigate the increased blood pressure due to HBOC-201. Animals were resuscitated by three 10 ml/kg infusions of either HBOC-201 or Hextend with and without NaNO(2). All vital signs, coagulation and blood chemistry were measured for 2 hr. HBOC-201-vasoconstriction was attenuated only after the first 10.8 μmol/kg NaNO(2) infusion. Complete abolition was obtained with the highest 3 NaNO(2) dose, but side effects were observed. There was no reduction in platelet function due to NaNO(2). NaNO(2) ability to reduce HBOC-201 vasoactivity was transient and 10.8 μmol/kg NaNO(2) seems an acceptable dose for further investigation.

Experimental data, obtained during the course of several years, are connected into a coherent picture, which may help research for the development of HBOCs as therapeutic agents. Oxygen affinity, scavenging of nitric oxide, and yield of production of hemoglobin based oxygen carriers were the areas under consideration.

The intraperitoneal instillation of perfluorocarbons augmented systemic oxygenation and was protective in mesenteric ischemia-reperfusion and experimental lung injury. To study biocompatibility and potential anti-inflammatory effects of intraperitoneal perfluorocarbons, we evaluated the influence of perfluorohexane and/or inflammatory stimuli on human mesothelial cells in vitro. Perfluorohexane exposure neither impaired cell viability nor induced cellular activation. TNFα enhanced ICAM-1 expression, which was not attenuated by simultaneous perfluorohexane treatment. Concentration of intracellular surfactant protein A tended to be higher in perfluorohexane treated cells compared to controls. Our in vitro data add further evidence that intraperitoneal perfluorocarbon application is feasible without adverse local effects.

We have developed a strategy to immobilize β-galactosidase as a model enzyme by using polymeric supports having Schiff bases, which were prepared from (aminomethyl)polystyrene and 2-phenlyindole-3-carboxaldehyde by condensation. β-galactosidase was immobilized onto the new polymer supports via covalent bonds. The influence of temperature, pH, reusability, and storage capacity on the free and immobilized β-galactosidase was investigated. Our results indicate that the (aminomethyl)polystyrene with Schiff bases is most suitable for the immobilization of β-galactosidase. These kinds of new supports can be used for the immobilization of β-galactosidase due to their strong storage capacity and reusability.