Real-time and label-free biosensing using moiré pattern generated by bioresponsive hydrogel

Semin Kim, Geehong Kim, Yong Woo Ji, Chae Eun Moon, Yuna Jung, Hyung Keun Lee, Jae Jong Lee, Won Gun Koh

Research output: Contribution to journalArticlepeer-review


Bioresponsive hydrogels are smart materials that respond to various external stimuli and exhibit great potential as biosensors owing to their capability of real-time and label-free detection. Here, we propose a sensing platform based on bioresponsive hydrogels, employing the concept of moiré patterns. Two sets of line patterns with different pitch sizes are prepared; a hydrogel grating whose pitch size changes according to external stimuli and a reference grating with constant pitch size. The volume changes of the hydrogel caused by external stimuli changes the pitch size of the hydrogel grating, and subsequently, the pitch sizes of the moiré patterns (moiré signal), whose values can be obtained in a real-time and label-free manner through customized moiré microscopy and signal processing. After confirming that the pH-induced swelling of hydrogel could be monitored using moiré patterns, we performed moiré pattern-based detection of specific proteins using protein-responsive hydrogel that underwent shrinking via interaction with target proteins. Brain-derived neurotrophic factor and platelet-derived growth factor were selected as the model proteins, and our proposed system successfully detected both proteins at nanomolar levels. In both cases, the pitch size change of hydrogel grating was monitored much more sensitively using moiré patterns than through direct measurements. The changes in the moiré signals caused by target proteins were detected in ex-vivo environments using a custom-made intraocular lens incorporating the hydrogel grating, demonstrating the capability of the proposed system to detect various markers in intraocular aqueous humor, when implanted in the eye.

Original languageEnglish
Pages (from-to)383-393
Number of pages11
JournalBioactive Materials
Publication statusPublished - 2023 May

Bibliographical note

Funding Information:
This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government ( Ministry of Science and ICT ) ( NRF-2017M3A7B4041798 , NRF-2021R1A2C4001596 , and NRF-2017M3D1A1039289 ).

Publisher Copyright:
© 2022 The Authors

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Biomaterials
  • Biomedical Engineering


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