• Journal of Microbiology and Biotechnology
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• 제22권6호
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• pp.849-855
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• 2012

Plant growth-promoting rhizobacteria (PGPR) pseudomonads have a large number of lipopolysaccharides on the cell surface, which induces immune responses. Cd-resistant PGPR prevalent at the Cd-affected sites under biophytostabilization was monitored. Transmissiom electron microscopy was used to the study the behavior of tolerance of PGPR to cadmium level and its effect on pseudomonad strains (Z9, S2, KNP2, CRPF, and NBRI). An immunosensor was developed by immobilizing antibody (anti-Z9 or anti-S2) against selected PGPR on a piezoelectric quartz crystal microbalance (QCM). Immunosensors were found to supplement the inherent specificity of antigen-antibody reactions with the high sensitivity of a physical transducer. On comparison of the efficiency of detection with ELISA, the spectrophotometric technique, the developed immunosensor was found to be more sensitive, fast, and reliable even after regeneration for several times. Thus, the immunosensor may be used for future detection of PGPR strains after automation of the screening process.

• 전기학회논문지
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• 제56권8호
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• pp.1424-1429
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• 2007

This paper presents a simple and reliable one-touch type multi-immunosensing lab-on-a-chip (LOC) detecting antibodies as multi-disease markers using electrochemical method suitable for a portable point-of-care system (POCS). The multi-stacked LOC consists of a PDMS space layer for liquids loading, a PDMS valve layer with 50 im in height for the membrane, a PDMS channel layer for the fluid paths, and a glass layer for multi electrodes. For the disposable immunoassay which needs sequential flow control of sample and buffer liquids according to the designed strategies, reliable and easy-controlled on-chip operation mechanisms without any electric power are necessary. The driving forces of sequential liquids transfer are the capillary attraction force and the pneumatic pressure generated by air bladder push. These passive fluid transport mechanisms are suitable for single-use LOC module. Prior to the application of detection of the antibody as a disease marker, the model experiments were performed with anti-DNP antibody and anti-biotin antibody as target analytes. The flow test results demonstrate that we can control the fluid flow easily by using the capillary stop valve and the PDMS check valves. By the model tests, we confirmed that the proposed LOC is easily applicable to the bioanalytic immunosensors using bioelectrocatalysis.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.549-549
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• 2012

Early detection of cancer biomarkers in the blood is of vital importance for reducing the mortality and morbidity in a number of cancers. From this point of view, immunosensors based on nanowire (NW) and carbon nanotube (CNT) field-effect transistors (FETs) that allow the ultra-sensitive, highly specific, and label-free electrical detection of biomarkers received much attention. Nevertheless 1D nano-FET biosensors showed high performance, several challenges remain to be resolved for the uncomplicated, reproducible, low-cost and high-throughput nanofabrication. Recently, two-dimensional (2D) graphene and reduced GO (RGO) nanosheets or films find widespread applications such as clean energy storage and conversion devices, optical detector, field-effect transistors, electromechanical resonators, and chemical & biological sensors. In particular, the graphene- and RGO-FETs devices are very promising for sensing applications because of advantages including large detection area, low noise level in solution, ease of fabrication, and the high sensitivity to ions and biomolecules comparable to 1D nano-FETs. Even though a limited number of biosensor applications including chemical vapor deposition (CVD) grown graphene film for DNA detection, single-layer graphene for protein detection and single-layer graphene or solution-processed RGO film for cell monitoring have been reported, development of facile fabrication methods and full understanding of sensing mechanism are still lacking. Furthermore, there have been no reports on demonstration of ultrasensitive electrical detection of a cancer biomarker using the graphene- or RGO-FET. Here we describe scalable and facile fabrication of reduced graphene oxide FET (RGO-FET) with the capability of label-free, ultrasensitive electrical detection of a cancer biomarker, prostate specific antigen/${\alpha}$ 1-antichymotrypsin (PSA-ACT) complex, in which the ultrathin RGO channel was formed by a uniform self-assembly of two-dimensional RGO nanosheets, and also we will discuss about the immunosensing mechanism.

• 한국식품위생안전성학회지
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• 제33권3호
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• pp.193-199
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• 2018

본 연구에서는 유전자 변형 옥수수(GM 옥수수)에 특이한 단크론성 항체를 개발하고 이에 대한 특성을 확인하는 연구를 수행하고자 하였다. 먼저 형질전환 대장균으로부터 PAT 단백질을 발현시킬 수 있는 시스템을 확립하였고, 재조합 PAT 단백질을 대량 생산하여 항원으로 사용하였다. 준비된 항원을 면역한 결과 재조합 PAT 단백질의 항원성은 매우 높은 것으로 확인되었으며, 세포융합과 클로닝을 통해 12 종의 hybridoma를 확립하였고 western blot 결과 10 종의 hybridoma가 재조합 PAT 단백질과 강한 반응성을 나타내었다. 10종의 hybridoma가 생산하는 항체가 실제 GM 옥수수에 반응하는지를 추가의 western blot으로 분석한 결과 2종의 단크론성 항체(PATmAb-7 and PATmAb-12)가 재조합 PAT 단백질뿐만 아니라 실제 GM 옥수수 중 PAT와 반응하는 것으로 확인되었다. 항체를 대량 생산하고 정제한 후 2종의 항체는 SDS-PAGE 상에서 대표적인 항체의 분리패턴(heavy와 light chain)을 나타내었고, 전형적인 $IgG_1$과 ${\kappa}$ type으로 확인되었다. 정제된 단크론성 항체는 특성을 조사한 결과 다른 GMO에서 발현될 수 있는 재조합 단백질과 non-GM 옥수수 추출물에는 반응성이 없고 PAT 단백질에만 특이적으로 반응하는 것을 확인할 수 있었다. PATmAb-7 를 이용한 간접효소면역분석법의 검출한계는 0.3 ng/mL 수준으로 기준의 유전자변형 콩 면역분석법과 비교했을 때 높은 민감도를 나타내었다. 이상의 결과로 볼 때 개발된 2종의 항체(PATmAb-7 and PATmAb-12)는 GM 옥수수에서 발현되는 PAT 단백질에 특이적으로 반응하는 항체로 확인되었고, 2종의 항체를 이용한 면역분석법과 바이오센서의 개발 가능성을 제시할 수 있었다.