Colorimetric diagnostic capillary enabled by size sieving in a porous hydrogel

John Mello Camille C. Guzman, Sheng Min Hsu, Han Sheng Chuang

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


Handy and disposable point-of-care diagnostics facilitate the early screening of severe diseases in resource-limited areas. To address urgent needs in inconvenient sites, a simple colorimetric diagnostic device equipped with a capillary tube with porous hydrogel and immunocomplex particles was developed for the rapid detection of biomarkers (16 min). In this device, probe particles attach to capture particles (dp = 40 µm) and form sandwiched immunocomplexes in the presence of target biomarkers, and a red color progressively emerges when the sandwiched immunocomplex particles are blocked by the porous hydrogel embedded inside the glass capillary. Colorimetric aggregation was recorded using a smartphone and analyzed with imaging software. The limit of detection reached 1 ng/mL and showed a maximum of 79% accuracy compared with that obtained through a conventional spectrophotometric technique. The level of a diabetic retinopathy (DR) biomarker, lipocalin-1 (LCN-1), was measured in 1 µL of a human tear sample and used in testing the practicability of the proposed device. All healthy subjects showed lower intensity levels than the other diabetic counterparts (proliferative DR or nonproliferative DR patients), implying the potential of this device in clinical applications. Overall, the diagnostic device facilitates point-of-care-testing and provides a low-cost (~1 USD), compact, and reliable tool for early diagnosis in resource-limited areas.

Original languageEnglish
Article number130
Issue number10
Publication statusPublished - 2020 Sept 23

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry
  • Instrumentation
  • Engineering (miscellaneous)
  • Biotechnology
  • Biomedical Engineering
  • Clinical Biochemistry


Dive into the research topics of 'Colorimetric diagnostic capillary enabled by size sieving in a porous hydrogel'. Together they form a unique fingerprint.

Cite this