Browsing by Author "Su, Hui-Wen"

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Label-free immunodetection of the cancer biomarker CA125 using high-Delta n liquid crystals
(2014-07-01)
Su, Hui-Wen
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Lee, Yun-Han
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Lee, Mon-Juan
;
Hsu, Yi-Chiang
;
Lee, Wei
A label-free and array-based optical liquid-crystal (LC) immunodetection technique for the detection of CA125 antigen, a protein biomarker most frequently used for ovarian cancer detection, was demonstrated with a nematic LC with larger birefringence (Delta n) to promote sensitivity in detecting biomolecules. The LC-based immunodetection offers an alternative and sensitive approach for the detection of biomarker proteins, with the potential of replacing conventional immunoassays used in biochemical studies and clinical laboratories. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License.
Surface modification of alignment layer by ultraviolet irradiation to dramatically improve the detection limit of liquid-crystal- based immunoassay for the cancer biomarker CA125
(2015-05-01)
Su, Hui-Wen
;
Lee, Mon-Juan
;
Lee, Wei
;
影像與生醫光電研究所
;
Institute of Imaging and Biomedical Photonics
Liquid crystal (LC)-based biosensing has attracted much attention in recent years. We focus on improving the detection limit of LC-based immunoassay techniques by surface modification of the surfactant alignment layer consisting of dimethyloctadecyl[3-(trimethoxysilyl) propyl] ammonium chloride (DMOAP). The cancer biomarker CA125 was detected with an array of anti-CA125 antibodies immobilized on the ultraviolet (UV)-modified DMOAP monolayer. Compared with a pristine counterpart, UV irradiation enhanced the binding affinity of the CA125 antibody and reproducibility of immunodetection in which a detection limit of 0.01 ng/ml for the cancer biomarker CA125 was achieved. Additionally, the optical texture observed under a crossed polarized microscope was correlated with the analyte concentration. In a proof-of-concept experiment using CA125spiked human serum as the analyte, specific binding between the CA125 antigen and the anti-CA125 antibody resulted in a distinct and concentration-dependent optical response despite the high background caused by nonspecific binding of other biomolecules in the human serum. Results from this study indicate that UV modification of the alignment layer, as well as detection with LCs of large birefringence, contributes to the enhanced performance of the label-free LC-based immunodetection, which may be considered a promising alternative to conventional label-based methods. (C) 2015 Society of Photo-Optical Instrumentation Engineers (SPIE)