• Food Science and Biotechnology
• /
• 제17권6호
• /
• pp.1365-1367
• /
• 2008

The antibacterial activity of chitosan against Escherichia coli was investigated in the presence of NaCl, sucrose, and ethanol to assess the potential use of chitosan as a biopreservative in food products containing these components. The inhibitory activity of chitosan decreased slightly upon the addition of NaCl and sucrose, respectively to culture broth containing 100 ppm of chitosan (Mw 3,000), while the addition of ethanol enhanced the inhibitory activity of chitosan on growing cells. The addition of these components to non-growing cells prior to chitosan treatment demonstrated that NaCl protected the cells from the inhibitory activity of chitosan, while sucrose had no effect. Ethanol addition to non-growing cells increased cell death by chitosan treatment. Finally, binding of fluorescein isothiocyanate (FITC)-labeled chitosan to E. coli was measured in the presence of the food components. The FITC-labeled chitosan binding to cells decreased upon NaCl addition, was not affected by sucrose, and increased following treatment with ethanol.

• Macromolecular Research
• /
• 제15권6호
• /
• pp.513-519
• /
• 2007

Self-assembled nanoparticles have great potential to act as vehicles for hydrophobic drug delivery. Understanding nanoparticle cellular internalization is essential for designing drugs intended for intracellular delivery. Here, the endocytosis and exocytosis of fluorescein isothiocyanate (FITC)-conjugated glycol chitosan (FGC) self-assembled nanoparticles were investigated by flow cytometry and confocal microscopy. The cellular internalization of FGC nanoparticles was initiated by nonspecific interactions between nanoparticles and cell membranes. Although adsorptive endocytosis of the nanoparticles occurred quickly, significant amounts of FGC nanoparticles were exocytosed, particularly in the early stage of endocytosis. The amount of exocytosed nanoparticles was dependent on the pre-incubation time with nanoparticles, suggesting that exocytosis is dependent on the progress of endocytosis. FGC nanoparticles internalized by adsorptive endocytosis were distributed in the cytoplasm, but not in the nucleus. In vitro cell cycle analysis demonstrated that FGC nanoparticles delivered paclitaxel into the cytoplasm and were effective in arresting cancer cell growth.

• Korean Chemical Engineering Research
• /
• 제48권2호
• /
• pp.178-184
• /
• 2010

본 논문에서는 생체적합성 고분자들의 자기 조립 특성을 이용하여 마이크론 단위의 캡슐을 제조하여, 캡슐 내부에 단백질을 넣고 시간과 pH에 따른 방출 거동을 고찰하였다. 본 연구에서는 키토산과 헤파린 그리고 알지네이트를 사용하여 동공(hollow) 캡슐을 제조하였다. 멜라민과 포름알데히드를 일정 비율로 혼합하여, 표면에 전하를 가지는 마이크론 단위의 core를 제조한 후, 음전하를 가지는 헤파린 혹은 알지네이트를 core 위에 흡착시키고, 양전하를 띠는 키토산을 흡착시킨 후, core 위에 교대로 흡착시켜 Multilayer를 형성시켰다. 4 층을 쌓은 후에 HCl을 이용하여 pH 2로 조절하면, core는 제거되고 속이 비어 있는 캡슐을 제조할 수 있었다. 동공 캡슐은 투과전자현미경, 표면주사현미경 및 광학현미경으로 관찰하였다. 이러한 캡슐은 pH에 따라서 각기 다른 거동을 보이는데, 본 연구에서는 내부에 FITC-albumin을 넣어 UV분광기로 방출되는 상대적인 양을 관찰한 결과, 키토산-헤파린 캡슐과 키토산-알지네이트 캡슐은 각기 다른 pH에서 개폐됨을 알 수 있었다.

• Journal of Pharmaceutical Investigation
• /
• 제31권4호
• /
• pp.241-256
• /
• 2001

Alginate microspheres, containing fluorescein isothiocyanate-bovine serum albumin (FITC-BSA) or green fluorescent protein (GFP) were prepared and used as a model drug to develop the oral vaccine delivery system. The alginate microspheres were coated with poly-L-lysine or chitosan. Two methods, w/o-emulsion and spray, were used to prepare alginate microspheres. To optimize preparation conditions, effects of several factors on the particle size and particle morphology of microsphere, and loading efficiency of model antigen were investigated. In both preparation methods, the particle size and the loading efficiency were enhanced when the concentration of sodium alginate increased. In the w/o-emulsion preparation method, as the concentration of Span 80 was increased from 0.5% to 2%, the particle size was decreased, but the loading efficiency was increased. The higher the emulsification speed was, the smaller the particle size and loading efficiency were. The concentration of calcium chloride did not show any effect on the particle size and loading efficiency. In the spray preparation method, the particle size was increased as the nozzle pressure $(from\;1\;kgf/m^2\;to\;3\;kgf/m^2)$ and spray rate was raised. Increasing calcium chloride concentration (<7%) decreased the particle size, in contrast to no effect of calcium chloride concentration on the w/o-emulsion preparation method. Alginate microspheres prepared by two methods were different in the particle size and loading efficiency, the particle size of microspheres prepared by the spray method was about $2-6\;{\mu}m$, larger than that prepared by the w/o emulsion method $(about\;2{\mu}m)$, and the loading efficiency was also higher with spray method. Furthermore, drying process for the microspheres prepared by the spray was simpler and easier, compared with the w/o emulsion preparation. Therefore, the spray method was chosen to prepare alginate microspheres for further experiments. Release pattern of FITC-BSA in alginate microspheres was evaluated in simulated intestinal fluid and PBS (phosphate buffered saline). Dissolution rate of FITC-BSA from alginate/chitosan microsphere was lower than that from alginate microsphere and alginate/poly-L-lysine microsphere. By confocal laser scanning microscope, it was revealed that alginate/FITC-poly-L-lysine microspheres were present in close apposition epithelium of the Peyer's patches of rabbits following inoculation into lumen of intestine, which proved that microspheres could be taken up by Peyer's patch. In conclusion, it is suggested that alginate microsphere prepared by spray method, showing a particle size of & $10\;{\mu}m$ and a high loading efficiency, can be used as a model drug for the development of oral vaccine delivery system.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권18호
• /
• pp.7611-7615
• /
• 2014

Aims: To prepare 5-fluorouracil (5-Fu) nanoparticles with higher encapsulation efficiency and drug loading, and then investigate interaction with the SGC-7901 gastric cancer cell line. Materials and Methods: Prescription was optimized by orthogonal experiments, the encapsulation efficiency and loading capacity were tested by high-performance liquid chromatography, and inhibition of proliferation by 5-Fu nanoparticles and 5-Fu given to cells for 24, 48 and 72 hours was investigated by methyl thiazolyl tetrazolium assay (MTT). In addition, 5-Fu nanoparticles were labeled by fluorescein isothiocyanate (FITC), and absorption into cells was tested by flow cytometry. Results: The optimal conditions for preparation were concentrations of 5-Fu of 5mg/ml, of $CaCl_2$ of 60 mg/ml and of chitosan of 2 mg/ml. With a stirring speed of 1200rpm, encapsulation efficiency of 5-Fu nanoparticles was $55.4{\pm}1.10%$ and loading capacity was $4.22{\pm}0.14%$; gastric cancer cells were significantly inhibited by 5-Fu nanoparticles in a time and concentration dependent manner, and compared to 5-Fu with slower drug release, in a certain concentration range, inhibition with 5-Fu nanoparticles was stronger. 5-Fu nanoparticles were absorbed by the cells in line with the concentration. Conclusions: 5-Fu nanoparticles can inhibit growth of gastric cancer cells in vitro to a greater extent than with 5-Fu with good adsorption characteristics, supporting feasibility as a carrier.