• 대한의생명과학회지
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• 제13권3호
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• pp.175-182
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• 2007

In vitro ciprofloxacin (CFX)-release study and bioassay using microorganisms were performed to estimate the retention of the antimicrobial activity of the CFX-incorporated central venous catheters (CFX-CVCs). The release experiments were carried out under the optional CFX-release conditions to mimic the in vivo environment. The release of CFX experienced an initial burst followed by a slow and steady matrix-diffusion controlled release. The 1.0CP (polyurethane catheter containing 1.0% (w/w) of CFX) under dynamic condition showed a near zero-order CFX release profile, which is beneficial for the long-tenn antimicrobial activity. The modified Kirby-Bauer method was performed employing S. aureus and E. coli to evaluate the retention of antimicrobial activity of the catheters retrieved from the release experiments. The 1.0CP showed the long-term antimicrobial activity (${\geq}\;21$ days) against both S. aureus and E. coli. These results indicate that 1.0CP is useful as a long-tenn indwelling CVC.

• Journal of Microbiology and Biotechnology
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• 제15권6호
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• pp.1178-1182
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• 2005

Survival of thermotolerant Lactobacillus reuteri KUB-AC5 in $20\%$ (w/v) skim milk was found to be $11.3\%$ after spray drying by using a pilot scale spray dryer with inlet temperature at $170^{\circ}C$ and outlet temperature at $85^{\circ}C$. The ability of dried cell to produce antimicrobial activity was not affected by the spray drying. The model system for predicting viability of spray-dried L. reuteri KUB-AC5 during long-term storage was established, based on the Arrhenius equation, and verified by experimental data, because the viability of cells during storage can be correlated with storage temperature. The viability during storage at $30^{\circ}C$ declined more rapidly than that storage at $4^{\circ}C$.

• The Journal of Advanced Prosthodontics
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• 제9권3호
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• pp.217-223
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• 2017

PURPOSE. This study investigated the effects of silver nanoparticle (SN) loading into hydraulic calcium silicate-based Portland cement on its mechanical, antibacterial behavior and biocompatibility as a novel dental bone substitute. MATERIALS AND METHODS. Chemically reduced colloidal SN were combined with Portland cement (PC) by the concentrations of 0 (control), 1.0, 3.0, and 5.0 wt%. The physico-mechanical properties of silver-Portland cement nanocomposites (SPNC) were investigated through X-ray diffraction (XRD), setting time, compressive strength, solubility, and silver ion elution. Antimicrobial properties of SPNC were tested by agar diffusion against Streptococcus mutans and Streptococcus sobrinus. Cytotoxic evaluation for human gingival fibroblast (HGF) was performed by MTS assay. RESULTS. XRD certified that SN was successfully impregnated in PC. SPNC at above 3.0 wt% significantly reduced both initial and final setting times compared to control PC. No statistical differences of the compressive strength values were detected after SN loadings, and solubility rates of SPNC were below 3.0%, which are acceptable by ADA guidelines. Ag ion elutions from SPNC were confirmed with dose-dependence on the concentrations of SN added. SPNC of 5.0 wt% inhibited the growth of Streptococci, whereas no antimicrobial activity was shown in control PC. SPNC revealed no cytotoxic effects to HGF following ISO 10993 (cell viability > 70%). CONCLUSION. Addition of SN promoted the antibacterial activity and favored the bio-mechanical properties of PC; thus, SPNC could be a candidate for the futuristic dental biomaterial. For clinical warrant, further studies including the inhibitory mechanism, in vivo and long-term researches are still required.

• Corrosion Science and Technology
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• 제17권2호
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• pp.74-80
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• 2018

The electronic industries require environmentally-friendly and highly functional materials to enhance the quality of human life. Home appliances require insect repellent steels that work to protect household microwave ovens from incurring damage by insects such as fire ants and cockroaches in tropical regions. Thus, POSCO has developed new types of functional steels, coated with an array of organic-inorganic hybrid composites on the steel surface, to cover panels in microwave ovens and refrigerators. The composite solution uses a fine dispersion of hybrid solution with polymeric resin, inorganic and a pyrethroid additive in aqueous media. The hybrid composite solution coats the steel surface, by using a roll coater and is cured using an induction curing furnace on both the continuous galvanizing line and the electro-galvanizing line. The new steels were evaluated for quality performances, salt spray test for corrosion resistance and biological performance for both insect repellent and antimicrobial activity. The new steels with organic-inorganic composite coating exhibit extraordinarily biological functionalities, for both insect repellent and antimicrobial activities for short and long term tests. The composite-coating solution and experimental results are discussed and suggest that the molecular level dispersion of insecticide on the coating layer is key to biological functional performances.

• 한국미생물·생명공학회지
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• 제29권1호
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• pp.50-55
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• 2001

B. subtilis cx1이 생산하는 박테리오신(BSCX1)을 부분 정제하고 특성을 규명하였다. BSCX1은 pH 안정성 실험에서 pH 2.5~9.5 구간에서도 안정되게 항균활성을 유지하였다. 각종 효소에 대한 안정성 실험에서는 protease, trypsin, proteinase K, 그리고 carboxypeptidase로 처리하였을 때는 완전히 항균활성이 사라졌고, $\alpha$-amylase, lipase, aminopeptidase는 항균활성에 영향을 미치지 못하였다. 이상의 결과로 본 항균물질이 단백질계열의 물질이며 당이나 지질 결합은 항균활성에 큰 영향을 미치지 않는 것으로 추정되었다. 그러나 열에는 불안정하여 $60^{\circ}C$이상에서는 15분 안에 완전히 그 항균활성을 상실하였으며 $50^{\circ}C$ 에서는 15분만에 역가의 50%가 실활 되었다. 이에 반하여 저온에서는 무척 안정하여 $-20^{\circ}C$와 $-70^{\circ}C$에서 수개월간 보관하여도 여전히 항균활성을 그대로 유지하였다. Tricin-SDS-PAGE를 통하여 BSCX1의 분자량은 약 9,500 dalton으로 확인되었ekl. BSCX1은 pH2.5에서 9.5에 이르는 넓은 pH 영역에서 그 활성을 유지하므로, 기존에 개발된 nisin이나 유산균 유래의 항균물질이 pH 안정성이 떨어진다는 단점을 보완할 수 있는 생물학적 식품보존제로서의 개발 가능성을 높이 시사하였다.

• 한국염색가공학회지
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• 제21권1호
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• pp.1-9
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• 2009

A lot of research has been made over the recent decade to develop testing packages with antimicrobial properties to improve food safety. In this study, a new method, experimental device and technology for environmental corresponding packages of polypropylene (PP) film has been developed to provide effective temperature buffering during the transport/long-term storage of grains or foodstuffs from the supplier to the market. This quantitatively optimized mixing system enabled to produce PP films with the 700$\sim$1,400d (width;1.5$\sim$3mm, thickness;0.01$\sim$0.5mm). In the whole mixing systems, the finely-granulated inorganic illite and PP virgin chip for master batch (M/B) chip was calculated by digital measurement methods, and then the M/B chip for PP film was adapted through a air jet and PP grinding method. The prepared PP film was characterized with tensile strength and elongation, far infrared radiation (FIR) emissivity, antimicrobial activity and deodorization properties. The results revealed that the two differently grain-sized illite could be show homogeneously dispersed on PP chip surface, and as the increasing of illite content, the FIR emissivity and the anion emission rate of film was increasingly improved. In both of 325 and 1,500 mesh-sized illite contained PP chip, of course the antimicrobial activity was good. But the ultimate deodorization rate for ammonia gas of PP film were found to be approximately the same.

• Animal Bioscience
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• 제35권4호
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• pp.631-637
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• 2022

Objective: Surface disinfection is important in the proper running of livestock farms. However, disinfection of farm equipment and facilities is difficult because they are made of different materials, besides having large surface areas and complex structures. 3-(trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride (Si-QAC) is a quaternary ammonium salt-based disinfectant that attaches to various surfaces by forming covalent bonds and maintains its disinfecting capacity for a considerable time. Our aim was to evaluate the potential use of Si-QAC for disinfection of farm equipment and facilities. Methods: The short- and long-term antimicrobial and antiviral effects of Si-QAC were evaluated in both laboratory and farm settings using modified quantitative assessment method based on the standard operating procedures of the United States Environmental Protection Agency. Results: Si-QAC was highly effective in controlling the growth of the Newcastle disease virus and avian pathogenic Escherichia coli. Electron microscopy revealed that the mechanism underlying the disinfection activity of Si-QAC was associated with its ability to damage the outer membrane of the pathogen cells. In the field test, Si-QAC effectively reduced viral contamination of surfaces of equipment and space. Conclusion: Our results suggest that Si-QAC has great potential as an effective chemical for disinfecting farm equipment and facilities. This disinfectant could retain its disinfection ability longer than other commercial disinfectants and contribute to better farm biosecurity.

• The Journal of Advanced Prosthodontics
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• 제6권3호
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• pp.207-214
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• 2014

PURPOSE. This study characterized the synthesis of a modified PMMA (Polymethyl methacrylate) denture acrylic loading platinum nanoparticles (PtN) and assessed its bacterial inhibitory efficacy to produce novel antimicrobial denture base material. MATERIALS AND METHODS. Polymerized PMMA denture acrylic disc ($20mm{\times}2mm$) specimens containing 0 (control), 10, 50, 100 and 200 mg/L of PtN were fabricated respectively. The obtained platinum-PMMA nanocomposite (PtNC) was characterized by TEM (transmission electron microscopy), SEM/EDX (scanning electron microscope/energy dispersive X-ray spectroscopy), thermogravimetric and atomic absorption spectrophotometer analysis. In antimicrobial assay, specimens were placed on the cell culture plate, and $100{\mu}L$ of microbial suspensions of S. mutans (Streptococcus mutans) and S. sobrinus (Streptococcus sobrinus) were inoculated then incubated at $37^{\circ}C$ for 24 hours. The bacterial attachment was tested by FACS (fluorescence-activated cell sorting) analysis after staining with fluorescent probe. RESULTS. PtN were successfully loaded and uniformly immobilized into PMMA denture acrylic with a proper thermal stability and similar surface morphology as compared to control. PtNC expressed significant bacterial anti-adherent effect rather than bactericidal effect above 50 mg/L PtN loaded when compared to pristine PMMA (P=.01) with no or extremely small amounts of Pt ion eluted. CONCLUSION. This is the first report on the synthesis and its antibacterial activity of Pt-PMMA nanocomposite. PMMA denture acrylic loading PtN could be a possible intrinsic antimicrobial denture material with proper mechanical characteristics, meeting those specified for denture bases. For clinical application, future studies including biocompatibility, color stability and warranting the long-term effect were still required.

• 한국미생물·생명공학회지
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• 제34권2호
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• pp.109-114
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• 2006

본 연구는 부패 생마로부터 저온성 부패균을 분리, 동정하고 분리균의 생육특성과 다양한 효소의 부패관련성을 조사하여, 생마 저온 장기저장 및 생마 가공식품 개발을 위한 기초자료를 제시할 목적으로 수행되었다. 저온 장기저장중의 부패생마로부터 서로 다른 13종의 저온세균을 분리, 동정하였으며, 다양한 온도에서 생마 절편을 이용한 부패력 측정 결과 분리균주 중 YAM-10및 YAM-12균주가 저온부패에 직접적으로 관련됨을 확인하였으며, 이들은 각각 Pseudomonas cepacia 및 Pseudomonas rhodesiae 동정되었다. 이들 균주는 20$^{\circ}C$에서도 우수한 amylase, CMCase, xylanase 활성을 나타내었으며 , 특히 amylase 활성은 생마 부패에 중요한 역할을 하는 것으로 판단되었다. YAM-10 및 YAM-12균주는 양파절편을 부패시키지는 못하였으며, 4$\sim$12$^{\circ}C$의 온도에서도 생육가능하며, pH 5 이하 및 pH 10 이상에서는 생육이 급격히 억제되었다. 현재 생마의 저온 장기저장 및 부패억제를 위한 저온성 Pseudomonas sp.의 제어와 생마부패에 관련되는 효소들의 특성과 저해에 대한 연구 및 저장성, 관능성이 강화된 산장, 염장 등을 통한 생마 가공식품 개발이 진행 중이다.

• Asian-Australasian Journal of Animal Sciences
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• 제19권11호
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• pp.1617-1622
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• 2006

Long-term storage of feeds or feedstuffs in high temperature and humid conditions can be difficult because of microbial contamination. Essential oil isolated from industrial waste citrus peel could be used as a preservative because it is likely to have anti-bacterial and anti-fungal activity. Our objective was to determine whether different levels (0.028, 0.056 and 0.112 g/kg) of citrus essential oil (CEO) would provide anti-microbial activity and enhance preservation of animal feed without influencing rumen fermentation. At 0.112 g/kg, CEO inhibited growth of Escherichia coli (ATCC 25922) and Salmonela enteritidis (IFO 3313). Growth of E. coli recovered after 24 h of incubation, but S. enteritidis continued to be inhibited for 72 h. Preservation of antibiotic-free diets for swine was assessed by observing anti-aflatoxin activity. Aflatoxin was detected in control feed samples on days 16 (8 ppb) and 21 (8 ppb) and in anti-fungal agent (AA) treated samples on days 16 (2 ppb) and 21 (4 ppb). However, aflatoxin was not detected in feed samples treated with CEO. Treatment with CEO and AA did not influence ruminal pH, dry matter digestibility (DMD) or organic matter digestibility (OMD) over 48 h of incubation in rumen fluid. Acetate and propionate were slightly higher with CEO treatment (p<0.05), but total concentration of volatile fatty acid (VFA) was not significantly affected by treatment. Ammonia-N concentration was slightly higher for the control treatment (p<0.05). This study showed that treating feed with CEO enhances preservation of animal feed without influencing in vitro rumen fermentation.