title: Detection of low-abundance biomarker lipocalin 1 for diabetic retinopathy using optoelectrokinetic bead-based immunosensing.
abstract: Early diagnosis of diabetic retinopathy (DR) is vital but challenging. DR is a common complication and a major cause of vision loss in patients with diabetes mellitus. Without appropriate medical intervention, visual impairment may become a great burden to our healthcare system. In clinical practice, the current diagnostic methods, such as fluorescence angiography and optical coherence tomography, remain constrained by non-quantitative examinations and individual ophthalmologists' experiences. Late diagnosis often prevents early treatment. To address the constraints on current diagnostics, this study developed an optoelectrokinetic bead-based immunosensing technique for detecting lipocalin 1 (LCN1), a DR biomarker. The concentration level of LCN1 in the tears of DR patients increases with DR severity. The immunoassay was dependent on the formation of sandwiched immunocomplexes on the particles. A secondary antibody labeled with dyes/quantum dots (QDs) was used to visualize the presence of the target antigens. Rapid electrokinetic patterning (REP), an optoelectrokinetic technique, was used to dynamically enhance the fluorescent signal by concentrating the modified particles. The limit of detection (LOD) of the technique could reach 110pg/mL. Only 1.5μL of a sample fluid was required for the measurement. Our results showed that highly sensitive and improved LOD is subjected to particle stacking, small particle size, and compact cluster. By labeling different particle sizes with dyes/QDs for LCN1 and TNF-α, we successfully used REP to detect the two DR biomarkers on the same platform. The development of an optoelectrokinetic bead-based immunosensing technique can provide new insights into diagnosing other low-abundance diseases in the future.
authors.affiliation: Department of Biomedical Engineering, National Cheng Kung University, Taiwan; Department of Urology, Chimei Medical Center, Tainan, Taiwan.
authors.forename: Jhih-Cheng
authors.initials: JC
authors.lastname: Wang
authors.affiliation: Department of Biomedical Engineering, National Cheng Kung University, Taiwan.
authors.forename: Hu-Yao
authors.initials: HY
authors.lastname: Ku
authors.affiliation: Department of Biomedical Engineering, National Cheng Kung University, Taiwan.
authors.forename: Tain-Song
authors.initials: TS
authors.lastname: Chen
authors.affiliation: Department of Biomedical Engineering, National Cheng Kung University, Taiwan; Medical Device Innovation Center, National Cheng Kung University, Taiwan. Electronic address: oswaldchuang@mail.ncku.edu.tw.
authors.forename: Han-Sheng
authors.initials: HS
authors.lastname: Chuang
mesh_terms: D000818:Animals; D055910:Antibodies, Immobilized / Q000737:chemistry; D015415:Biomarkers / Q000032:analysis; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D004396:Coloring Agents / Q000737:chemistry; D003930:Diabetic Retinopathy / Q000175:diagnosis*; D004574:Electromagnetic Fields; D004867:Equipment Design; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods; D054835:Lipocalin 1 / Q000032:analysis*; D055096:Optical Devices; D045663:Quantum Dots / Q000737:chemistry; D013666:Tears / Q000737:chemistry*; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis*
chemical_list: D055910:Antibodies, Immobilized; D015415:Biomarkers; D004396:Coloring Agents; D054835:Lipocalin 1; D014409:Tumor Necrosis Factor-alpha
keywords: Bead-based immunosensing; Biomarker; Diabetic retinopathy; Lipocalin 1; Optoelectrokinetic technique