• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.22 no.3
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• pp.127-134
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• 2016

In this study, Biodegradable masterbatch (M/B) was prepared by different kinds and content of biodegradable catalysts added to oxo biodegradable plastics. The bio film was prepared by adding biodegradable M/B to the polyethylene pellet, and the change of physical properties by UV and heat treatment and the stability as food packaging material were confirmed. As a result of the physical property change, Fe salt and Al salt bio film was superior to Ni salt bio film about a decrease in physical property. However, considering the raw material cost and industrial availability, M/B containing Fe salt was selected and additional experiments were conducted by concentration. The bio films prepared with Fe salt M/B 1.0, 1.5 and 2.0 wt% showed excellent physical properties.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.203.2-203.2
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• 2016

미생물이 스스로 생성한 고분자 물질에 싸이며 군집체를 형성한 바이오필름은 고체 표면에 부착되며 우리 생활 속에 다양한 형태로 발견할 수 있다. 바이오필름은 미생물에 적합하지 않은 외부 환경으로부터 미생물 스스로 보호하는 기능을 하며, 형성된 바이오필름은 오랜 기간 동안 생존하여 살균제나 항생제로부터 저항성을 가져 살균과정에서 제거되지 않고 2차오염을 야기할 수 있어 식품 가공 기계 및 수도관, 의료기기 등에 형성되었을 경우 식품 오염, 상처 감염 등의 원인이 된다. 이 때문에 위생과 바이오필름의 상관관계를 인지하고 이를 제어하기 위한 연구가 여러 방법으로 진행되고 있다. 대표적인 방법으로는 천연 향균제 개발, 쿼럼 센싱(Quoroum sensing)과 같이 미생물의 신호전달 체계를 차단하는 물질 개발 및 플라즈마 처리 등이 있다. 본 연구에서는 격자형식의 유전장벽방전(DBD) 형식의 플라즈마 소스를 개발하여 바이오필름의 효과적인 제어 가능성을 확인하고, 제어 방식의 관계를 파악하였다. 플라즈마 처리 대상의 화학적 분석을 위하여 유기물질 등을 사용해 플라즈마 처리수 내 화학물질 분석 시스템을 구축하여 이를 기반으로 플라즈마로 생성된 HNO2, NO2-, H2O2 등의 화학종이 가지는 바이오필름 제어 관계를 살펴보았으며, 화학적 방법인 제어효과와 비교하여 플라즈마의 바이오필름 제어 특성에 대해 살펴보았다. 본 발표에서 플라즈마의 바이오필름 제어효과에 대한 분석에 대해 더 자세한 결과가 발표될 예정이다.

• Journal of Life Science
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• v.31 no.1
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• pp.100-108
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• 2021

In the oral cavity, there are hundreds of microbial species that exist as planktonic cells or are incorporated into biofilms. The accumulation and proliferation of pathogenic bacteria in the oral biofilm can lead to caries and periodontitis, which are typical oral diseases. The oral bacteria in the biofilm not only can resist environmental stress inside the oral cavity, but also have a 1,000 times higher resistance to antibiotics than planktonic cells by genes exchange through the interaction between cells in the oral biofilm. Therefore, if the formation of oral biofilm is suppressed or removed, oral diseases caused by bacterial infection can be more effectively prevented or treated. In particular, since oral biofilms have the characteristic of forming a biofilm by gathering several bacteria, quorum sensing, a signaling system between cells, can be a target for controlling the oral biofilm. In addition, a method of inhibiting biofilm formation by using arginine, an alkali-producing substrate of oral bacteria, is used to convert the distribution of oral microorganisms into an environment similar to that of healthy teeth or inhibit the secretion of glucosyltransferase by S. mutans to inhibit the formation of non-soluble glucans. It can be a target to control oral biofilm. This method of inhibiting or removing the oral biofilm formation rather than inducing the death of pathogenic bacteria in the oral cavity will be a new strategy that can selectively prevent or therapeutic avenues for oral diseases including dental caries.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.118.2-118.2
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• 2016

몇몇의 박테리아들은 바이오필름을 형성하여 그들 스스로를 보호한다. 하지만 바이오필름으로 인해 악취와 질병 등의 문제가 많이 발생되고 있기 때문에 바이오필름을 형성하는 박테리아의 성장을 효율적으로 억제하기 위해 은 나노, 구리 나노입자들이 포함된 다양한 나노스케일의 재료들에 대한 연구가 활발히 진행되어오고 있다. 이들 연구의 주된 목표는 체내에서 독성은 나타내지 않으면서 항균성을 증가시키는 것에 있다. 특히, 구형으로 이루어진 나노입자와 높은 종횡비를 가지는 탄소나노튜브와 같이 차원이 다른 나노물질들의 복합체들은 세포독성을 최소화하면서 특정 박테리아에 대한 항균성을 향상시킬지도 모른다. 이번 연구에서는, 산 처리된 탄소나노튜브에 화학적인 방법을 이용하여 구리 이온을 각각 환원시켜 구리 나노-탄소나노튜브 복합체를 합성하였다. 이들 복합체는 transmission electron microscopy, X-ray diffractometry, energy-dispersive X-ray spectroscopy 를 이용하여 특성이 분석되었고 Methylobacterium spp., Sphingomonas spp. 와 E. coli 에 대하여 항균성이 평가되었다. 추가적으로 구리 나노-탄소나노튜브 복합체는 human fibroblast cells 에 대하여 세포독성이 평가되었고 제작된 마이크로칩 안에 형성된 바이오필름의 성장억제효과가 평가되었다. 결과적으로, 구리 나노-탄소나노튜브 복합체에서 바이오필름을 형성하는 Methylobacterium spp. 에 대하여 특이적으로 항균성을 나타냈으며 바이오필름이 형성된 마이크로칩에서 바이오필름을 제거 하는 것이 확인되었다.

• Journal of the KSME
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• v.52 no.8
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• pp.32-36
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• 2012

바이오필름은 미생물 즉 세균이 있는 모든 환경에서 관찰할 수 있다. 현재 거의 대부분의 산업에서 바이오필름에 대한 이해와 비용절감 및 기술고도화에 핵심적인 역할을 하는 경우가 점차 늘어나고 있다. 이 글은 바이오멤스(BioMEMS) 기술을 이용한 박테리아 바이오필름 연구들의 동향을 설명하고자 한다.

• Korean Journal of Microbiology
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• v.49 no.1
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• pp.17-23
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• 2013

Candida biofilms are organized microbial communities growing on the surfaces of host tissues or indwelling medical devices, and the biofilms show enhanced resistance against the conventional antifungal agents. The roots of Coptidis chinensis have been widely used for medicinal purposes in East Asia. The present study was aimed to assess the effect of C. chinensis aqueous extract upon preformed biofilms of 10 clinical Candida albicans isolates and the antifungal activities which contribute to inhibit the C. albicans biofilm formation. Its effect on preformed biofilms was judged using XTT [2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide)] reduction assay, and metabolic activity of all tested strains was reduced significantly ($57.3{\pm}14.7%$) at $98{\mu}g/ml$ of the C. chinensis extract. The extract damaged the cell membrane of C. albicans which was analyzed by fluorescein diacetate and propidium iodide staining. The anticandidal activity was fungicidal, and the extract obstructed the adhesion of C. albicans biofilms to polystyrene surfaces, arrested C. albicans cells at $G_o/G_1$ as well, and reduced the growth of biofilms or budding yeasts finally. The data suggest that C. chinensis has multiple antifungal effects on target fungi resulting in preventing the formation of biofilms. Therefore, C. chinensis holds great promise for exploring antifungal agents from natural products in treating and eliminating biofilm-associated Candida infection.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.37 no.4
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• pp.347-350
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• 2011

Biofilms are surface-attached microbial communities with phenotypic and biochemical properties distinct from free-living planktonic cells. Biofilm bacteria show much greater resistance than planktonic counterparts and much higher concentration of biocide is needed to treat biofilms compared to the dosage used for planktonic bacteria. As a result, alternative strategies or more effective agents exhibiting activity against biofilm-producing micro-organisms are of great interest. Therefore, we turned our attention to control of biofilm of S. aureus. The aims of this research are to investigate substances which inhibit the formation of biofilm by S. aureus and to suggest effective materials for controlling skin problems. We coated slide glasses with human placental collagen and the coverslip was incubated with test materials and bacteria. The coverslip was stained with crystal violet and we measured optical density of each sample. The biofilm inhibitory activity was calculated by crystal violet staining degrees. In this study, S. aureus ATCC 6538 was used as test organism. Our results show that both water soluble and insoluble Hinoki cypress polysaccharide strongly inhibited biofilm formation. Whereas, green tea and sunset hibiscus root extract promoted biofilm. Xylitol showed a concentration dependent effect; high concentration (3 % and 5 %) of xylitol reduced biofilm while promoted biofilm formation at a concentration of 1 %. These results support that Hinoki cypress polysaccharide and xylitol have ability to suppress biofilm formation.

• Economic and Environmental Geology
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• v.42 no.5
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• pp.435-444
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• 2009

In situ stabilization of heavy metals through adsorption onto indigenous bacterial biofilm developed on soil particles was investigated. Biofilms were developed in soil columns by supply of various carbon sources such as acetate, lactate and glucose. During development of biofilms, acetate, lactate, and glucose solutions were flew out from the soil columns with volume ratios of 98.5%, 97.3%, and 94.7%, respectively, when compared with soil column supplied with deionized water. Decrease in effluent amounts through the soil columns amended with carbon sources over time indicated the formation of biofilms resulting in decrease of soil porosity. Solutions of Cd, Cr(VI), Cu, Pb, and Zn were injected into the biofilms supported on soil particles in the columns, and the dissolved heavy metals in effluents were determined. Concentrations of dissolved Cd, Cr(VI), Cu, and Zn in the effluents through biofilm columns were lower than those of control column supplied with deionized water. The result was likely due to enhanced adsorption of the metals onto biofilms. Efficiency of metal removal by biofilms depended on the type of carbon sources supplied. The enhanced removal of dissolved heavy metals by bacterial biofilms in this study may be effectively applied to technical development of in situ stabilization of heavy metals in natural soil formation contaminated with heavy metals.

• 축산식품과학과 산업
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• v.8 no.1
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• pp.8-13
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• 2019

• Journal of dental hygiene science
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• v.16 no.4
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• pp.284-292
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• 2016

Water supplied through dental unit waterlines (DUWLs) has been shown to contain high number of bacteria. To reduce the contamination of DUWLs, it is essential to develop effective disinfectants. It is, however, difficulty to obtain proper DUWL samples for studies. The purpose of this study was to establish a simple laboratory model for reproducing DUWL biofilms. The bacteria obtained from DUWLs were cultured in R2A liquid medium for 10 days, and then stored at $-70^{\circ}C$. This stock was inoculated into R2A liquid medium and incubated in batch mode. After 5 days of culturing, it was inoculated into the biofilm formation model developed in this study. Our biofilm formation model comprised of a beaker containing R2A liquid medium and five glass rods attached to DUWL polyurethane tubing. Biofilm was allowed to form on the stir plate and the medium was replaced every 2 days. After 4 days of biofilm formation in the laboratory model, biofilm thickness, morphological characteristics and distribution of the composing bacteria were examined by confocal laser microscopy and scanning electron microscopy. The mean of biofilm accumulation was $4.68{\times}10^4$ colony forming unit/$cm^2$ and its thickness was $10{\sim}14{\mu}m$. In our laboratory model, thick bacterial lumps were observed in some parts of the tubing. To test the suitability of this biofilm model system, the effectiveness of disinfectants such as sodium hypochlorite, hydrogen peroxide, and chlorhexidine, was examined by their application to the biofilm formed in our model. Lower concentrations of disinfectants were less effective in reducing the count of bacteria constituting the biofilm. These results showed that our DUWL biofilm laboratory model was appropriate for comparison of disinfectant effects. Our laboratory model is expected to be useful for various other purposes in further studies.