• Journal of Pharmaceutical Investigation
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• v.24 no.4
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• pp.201-215
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• 1994

Recent development in the immunochemical technique has resulted in a new ultrasensitive analytical method known as liposome immunoassay (LIA). Liposome is a key element in performing liposome immunoassays, specifically designed to participate in immune reactions. A variety of markers can be encapsulated in liposomes and used as quantitative indicators of reactions. Liposome immunoassay based on agglutination, complement-mediated Iysis, cytolysin-mediated Iysis, detergent-mediated Iysis or destabilization of the liposomal membrane have been reviewed. The quantity of markers released from liposomes should be proportional to the concentration of the analytes. Therefore, liposomal agglutination and Iysis which are essential to liposomal Iysis are critically reviewed to provide a better understanding of liposome immunoassay. Based on the literature review of recent advances in liposome immunoassay for bioactive substances, this assay method may provide a convenient, specific and highly sensitive method for detecting and measuring trace amount of clinically relevant substances in the future.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.281-281
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• 1996

The immunoassay method is frequently used for the identification and quantitation of ultratrace amount of bioactive substances. Homogeneous liposome immunoassays, which can avoid the use of radioisotopes and separation steps, have recently been reported in many publications. Cytolysin-mediated liposome immunoassay using melittin ever been studied but showed limited applications. Here, we designed a homogeneous liposome immunoassay using Clostridium perfringens phospholipase C (PLC), an enzyme which catalyzes the hydrolysis of phosphatidylcholine in biological membranes, as a cytolysin.

• Journal of Microbiology and Biotechnology
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• v.18 no.10
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• pp.1689-1694
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• 2008

The ability to detect Salmonella spp. is essential in the prevention of foodborne illness. This study examined a Salmonella spp. detection method involving the application of immunomagnetic separation and immunoliposomes (IMS/IL) encapsulating sulforhodamine B (SRB), a fluorescent dye. A quantitative assay was conducted by measuring the fluorescence intensity of SRB that was produced from an immunomagnetic bead-Salmonella spp.-immunoliposome complex. The results indicated detection limits of $2.7{\times}10^{5}$ and $5.2{\times}10^{3}$ CFU/ml for Salmonella enterica subsp. enterica serovar Enteritidis (S. Enteritidis) and Salmonella enterka subsp. enterka serovar Typhimurium (S. Typhimurium), respectivley. The signal/noise ratio was improved by using 4% skim milk as a wash solution rather than 2% BSA. In addition, higher fluorescence intensity was obtained by increasing the liposome size. Compared with the conventional plating method, which takes 3-4 days for the isolation and identification of Salmonella spp., the total assay time of to h only including 6 h of culture enrichment was necessary for the Salmonella detection by IMS/IL. These results indicate that the IMS/ IL has great potential as an alternative rapid method for Salmonella detection.

• Journal of Microbiology and Biotechnology
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• v.13 no.4
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• pp.509-516
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• 2003

A model system for the immnunochemical detection of Escherichia coli O157:H7 using a combined immunomagnetic separation (IMS) and test-strip liposome immunoassay (LIA) procedure was developed. Immunomagnetic beads coated with anti-E. coli O157 IgG antibodies were used to separate the E. coli O157 (including the H7 serotype) from culture. Immunoliposomes, whose surface was conjugated to goat anti-E. coli O157:H7 IgG and which encapsulated the marker dye, sulforhodamine B, were used as a detection label. The test strip, onto which antibodies to goat IgG were immobilized, was the immunosensor capturing immunoliposomes that did not bind to E. coli O157:H7 on the immunomagnetic bead-E. coli O157:H7 complexes. In experiments, pure cell culture suspensions of $10^5 E.$ coli O157:H7 organisms per ml produced a measurable signal inhibition, whereas a weak yet detectable signal inhibition occurred with $10^3CFU/ml$. The inhibition signals increased, when the incubation time for IMS was extended to 90 min and higher IgG-tag density (0.4mol%) was used on the liposomes. With 0.2 and 0.4mol% IgG-tagged liposomes, the IMS-LIA procedure showed more improved signal inhibitions than those of a direct (no IMS) LIA. The combined assay, which measures the instantaneous signal from immunoliposomes, can be completed within 90 min, making it significantly faster than conventional plating methods and enzyme-linked immunosorbent assay (ELISA). Accordingly, it is quite feasible to use the combined immunoassay format of IMS and dye-loaded immunoliposomes for the detection of E. coli O157:H7.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2003.06a
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• pp.15-23
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• 2003

식품으로 인한 질병은 개인의 생명을 위협할 뿐 아니라 건전한 노동력의 상실로 생산성을 감소시키고 의료비를 증가시켜 개인의 행복 및 국가 경제에 부담을 준다 (Buzby et al. 1996, Mead et at. 2000). HACCP와 여러 식품안전에 관한 규제의 시행 등의 많은 노력에도 불구하고 Salmonella serotypes, Staphylococcus aureus, Camplobacter jejuni, Campylobacter coli, enterotoxigenic and enteroinvasive Escherichia coli, Clostridium perfringens, Bacillus cereus와 같은 식품기원 병원성 세균으로 인한 질병은 줄어들고 있지 않다. 오히려 외식 위주로 변해가는 생활습관은 식품을 통한 이들 병원성 세균의 전파가능성을 증가시키고 있다. 게다가 새로운 병원성균 (Yersinia enterocolitica, Listeria monocytogenes, E. coli 0157:H7, Aeromonas spp., Plesiomonas spp.) 의 출현 또는 특정 식품과 연관되어 나타나는 특정 subtype (Salmonella serotype Enteritidis) 의 출현은 이제까지 통용되어왔던 식품기원 세균을 위한 제어프로그램과는 다른 각도로 재원을 활용해야 할 동기를 부여하고 있다.

• Food Science of Animal Resources
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• v.23 no.3
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• pp.278-283
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• 2003

Feasibility tests on using liposomes for detecting food-borne pathogenic bacteria were studied with E. coli 0157:H7 as a model analyte. lmmunoliposomes, whose surface was conjugated with anti-E. coli 0157:H7 IgG and which encapsulated the marker dye, sulforhodamine B, were used for the detection label. Among the feasibility tests, the first test was to use a test-strip on which antibodies to anti-E. coli O157:H7 IgG were immobilized. In this format, immunoliposomes that did not bind to E. coli O157:H7 in sample were captured and then exhibited a visible signal which was inversely related with the number of E. coli O157:H7 in sample. The second test was a direct liposome assay followed by immunomagnetic separation. In this format, immunoliposomes which were bound to E. coli O157:H7 were lysed with detergent and produced a signal which was proportionally related with the number of E. coli O157:H7 in sample. The results from both formats indicate that liposomes can be utilized as a detection label.