Ko, Sanghag Bae, Hyunjun Kim, Daewon Lee, Yeonju Choi, Isaac Lee, Dain Choi, Dong hwan Kim, Hyung Chul Sohn, Seo Young Jeong, Yohan Chung, Seok Jung, Young Hee 2025-07-18T08:00:23Z 2025-07-18T08:00:23Z 2025-07-18 2025-08 1473-0197 https://pubs.kist.re.kr/handle/201004/152800 Alzheimer's disease (AD) is a serious health condition that exacerbates with age. Among various AD biomarkers, the measurement of the A beta 42/40 ratio (i.e., ratio of A beta 42 and A beta 40 concentrations) has garnered prominence for the early identification of AD patients and the development of disease-modifying treatments. Approaches such as positron emission tomography examinations and biomarker measurements in cerebrospinal fluid and blood plasma face constraints related to expense and procedural complexity. To address these issues, we developed and evaluated the efficacy of a portable platform for detecting amyloid beta (A beta) 40 and 42 in plasma, utilizing photooxidation-induced fluorescence amplification (PIFA). We conducted a comparative analysis of A beta 42/40 measurements between the PIFA and single-molecule immunoassay (SiMoA) platforms. By measuring 38 cases of subjective cognitive decline (SCD), 24 cases of amnestic mild cognitive impairment (aMCI), and 46 cases of AD dementia samples, we observed a significant difference in A beta 42/40 ratios between the SCD and aMCI groups. The PIFA platform demonstrated an area under the curve compared to that of the SiMoA platform, which is currently the most precise method for A beta 42/40 ratio measurement. Consequently, the PIFA platform presents a viable cost-effective tool for detecting the A beta 42/40 ratio. English Royal Society of Chemistry Portable platform for measuring amyloid beta 42/40 ratio via photooxidation-induced fluorescence amplification Article 10.1039/d5lc00235d 1 Lab on a Chip, v.25, no.16, pp.3993 - 4001 Lab on a Chip 25 16 3993 4001 N scie scopus 001513031600001 Biochemical Research Methods Chemistry, Multidisciplinary Chemistry, Analytical Nanoscience & Nanotechnology Instruments & Instrumentation Biochemistry & Molecular Biology Chemistry Science & Technology - Other Topics Instruments & Instrumentation Article ALZHEIMERS-DISEASE NATIONAL INSTITUTE GUIDELINES AD