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

To have advantages of reduced dosing frequency, improved bioavailability and effective delivery system of Cefuroxime Axetil, a Chitosan based intragastric sustained release microbead formulation of Cefuroxime Axetil was developed. The drug delivery system was prepared by ionotropic gelation of Chitosan in presence of sodium tripolyphosphate as polyanion and optimized by box-behnken experimental design. Response surface methodology was applied to evaluate various vitro characteristics of prepared mucoadhesive microbeads. Multiple independent variables were optimized to achieve responses of interest, thereby to get the desired sustained release profile of Cefuroxime Axetil in gastric environment.

Trypsin was immobilized by covalent binding to glutaraldehyde-activated silica with and without a spacer arm; 1,6-diaminohexane and polyethyleneglycol as well. The addition of polyethyleneglycol (PEG) to the immobilization media increased the activity of immobilized trypsin in organic solvents, whilst free trypsin activity disappeared under the same conditions. Thermal, pH, storage, and operational stabilities of the free and immobilized enzyme were found to be better than the free enzyme. Furthermore, use of immobilized enzyme for protein fragmentation was achieved by solid-phase, on-line, protein digestion in organic solvents. Reaction times were reduced to a few minutes and the sample handling was minimized.

Context: Cholera is a severe diarrheal disease that remains an important cause of illness and death in many parts of the world.

Objective: This study has been designed to check the immune-stimulating potential of antigens in their native and associated form as chitosan microparticles in vitro.

Material and methods: Chitosan microparticles were prepared by the ionic gelation technique. The cell envelope proteins (CEPs) isolated from Vibrio cholerae were loaded as antigenic material. The prepared microparticles were characterized for their morphology, loading efficiency, particle size, and zeta potential.

Results: The average particle size of CEPs-loaded chitosan microparticles was 2.24 µm and the zeta potential of loaded microparticles was less than blank microparticles. The in vitro release studies of CEPs from CEPs-loaded chitosan microparticles exhibited slow and extended release over a period of time. The higher release of cytokine profile, including interferon γ (IFN-γ), tumor necrosis factor α (TNF-α), and interlukin-6 (IL-6), was observed for CEPs-loaded chitosan microparticles in comparison to CEPs as native antigen.

Discussion: The particle size of microparticles was within the range for phagocytosis by macropahges, which affects the immunogenicity. The decrease in zeta potential from blank to loaded microparticles further confirms the loading of antigen. The slow and extended release of CEPs provides continuous stimulus of antigen for a longer period of time. The cytokine profiling has shown the advantage of loaded microparticles over native antigen.

Conclusion: The in vitro release studies and cytokine profiling strongly suggested that CEPs-associated chitosan microparticles could be a potential candidate for oral vaccination against Vibrio cholerae.

Carbazole substituted imines (2a-l) were prepared from N-methyl-3-amino carbazole with different aldehydes. The imines compounds undergo (2+2) cycloaddition reactions with in situ ketenes to produce β-lactam compounds (3a-l). The β-lactam compounds were tested as inhibitors of the xanthine oxidase (XO) purified from bovine milk. The results show that these compounds exhibit inhibitory effects on XO at low concentrations with IC(50) values ranging from 21.65 to 58.04 µM. The most effective compound for XO was 4-(4-chlorophenyl)-1-(9-ethyl-9H-carbazol-3-yl)-3-phenylazetidin-2-one with IC(50) of 21.65 μM. The lactams investigated here showed effective XO inhibitory effects, in the same range as the clinically used allopurinol.

The goal of this study was to investigate whether hemoglobin-based oxygen carrier (HBOC) attenuated ischemia/reperfusion (I/R)-induced kidney injury. Male SD rats were randomly divided into a sham group, I/R group, and HBOC group (injection of 0.1 gHb/kg PolyPHb). The ischemia was induced by bilateral renal pedicle cross-clamping for 45min. Then the clamp was released to allow 24h reperfusion. Without increasing blood pressure, PolyPHb reduced the blood urea nitrogen and creatinine in plasma and attenuated the tumor necrosis factor-α and interleukin-8 in kidney tissue. Therefore, our findings suggest that PolyPHb could reduce kidney injury after I/R injury, and this effect was probably associated with the depressed inflammatory response.

The water-soluble poly(methyl vinyl ether-co-maleic anhydride) copolymer-bovine serum albumin bioconjugates were synthesized in the presence of 1-ethyl-3-(3-dimetilamino-propyl) carbodiimide hydrochloride as cross-linking agents via microwave-assisted and conventional methods and characterized by size-exclusion chromatography and high-performance liquid chromatography. According to size-exclusion chromatography and high-performance liquid chromatography results, the bioconjugates synthesized in the microwave-assisted method are more stable and efficient than the conventional method. The reaction time is shortened from 17 hours to 15 minutes by means of the microwave-assisted method.

Prophenoloxidase (PPO) was purified from Galleria mellonella L. A 67-fold purification of the proenzyme with 352% yield was achieved by using a Sepharose 4B-L-tyrosine-p-amino benzoic acid affinity column. The purified enzyme was migrated as a single band on SDS-polyacrylamide gel electrophoresis. K(m) and V(max) values were 0.017 M and 1430.45 EU for catechol. Inhibition of PPO was investigated with inhibitors such as p-aminobenzoic acid, etyleneglycol, and ascorbic acid. Among them, ascorbic acid showed the strongest inhibitory activity with IC(50) value of 2.94 μM. The current paper represents new strategies for the biological control of the Galleria mellonella L. insect.

Spinal cord injury (SCI) is one of the most serious disorders in clinics, and the high disability rate and functional deficits are common issues in patients. Transplantation of bone-marrow-derived mesenchymal stromal cells (BMSCs) into the injured spinal cord is emerging as a novel method in the therapeutics of SCI; however, its application is limited by the poor survival rate of the transplanted cells and low differentiation rate into neurons. Our laboratory recently reported that electrical stimulation (ES) dramatically improves the survival rate of transplanted BMSCs and increases spinal cord functions in animals with spinal cord injury. In this paper, we asked whether implanted electro-acupuncture (iEA) can advance the beneficial effects from the ES treatment in animals with spinal cord injury. We showed that BMSCs transplantation alone resulted in significant functional recovery in animals. Interestingly, iEA with BMSCs treatment induced a significantly higher functional improvement in locomotor functions and SSEP compared to the BMSCs treatment alone. Additionally, we used molecular biology techniques and showed that BMSCs transplantation with iEA treatment significantly increased the number of surviving BMSCs compared to the BMSCs alone group. In conclusion, our experiment showed that the approach of coupling iEA electric stimulation and BMSCs transplantation remarkably promotes functional improvements in animals with spinal cord injury and holds promising potential to treat spinal cord injury in humans.

In this study, laccase enzyme (L) from Agaricus bisporus was immobilized by entrapment into polyacrylamide (PAAm) and semi-interpenetrating polymer networks (semi-IPNs) prepared with either polyacrylamide/κ-carragennan (0.05g) [PAAm/ κ-car (0.05)] or polyacrylamide/κ-carragennan (0.1 g) [PAAm/ κ-car (0.1)]. The optimum pH was 6.0 for free L, 8.0 for PAAm-L, 8.5 for PAAm/κ-car (0.05)-L, and 9.0 for PAAm/κ-car (0.1)-L. The optimum temperature was determined as 45°C for free L and 60°C for all immobilized laccases. After 27 days of storage at 4°C, free enzyme lost its initial activity whereas immobilized enzymes retained 56 % (-)80% of their initial activities. The immobilized samples were used repeatedly 35 times by retaining 28 %-58 % of their initial activity. K(m(app)) values were calculated as 0.088, 0.139, 0.133, and 0.131 mM and Vmax values were found to be 2.83 x 10(-3), 4.51×10(-3), 4.76×10(-3), and 4.97×10(-3) mM min(-1) for free L and PAAm-L, PAAm/κ-car (0.05)-L, and PAAm/κ-car (0.1)-L, respectively.