Label-Free Analysis of Multivalent Protein Binding Using Bioresponsive Nanogels and Surface Plasmon Resonance (SPR)

Hae Min Yang, Jie Ying Teoh, Guk Hee Yim, Yongdoo Park, Young Gyu Kim, Jongseong Kim, Dongwon Yoo

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


Precise identification of protein-protein interactions is required to improve our understanding of biochemical pathways for biology and medicine. In physiology, how proteins interact with other proteins or small molecules is crucial for maintaining biological functions. For instance, multivalent protein binding (MPB), in which a ligand concurrently interacts with two or more receptors, plays a key role in regulating complex but accurate biological functions, and its interference is related to many diseases. Therefore, determining MPB and its kinetics has long been sought, which currently requires complicated procedures and instruments to distinguish multivalent binding from monovalent binding. Here, we show a method for quickly evaluating the MPB over monovalent binding and its kinetic parameters in a label-free manner. Engaging pNIPAm-co-AAc nanogels with MPB-capable moieties (e.g., PD-1 antigen and biocytin) permits a surface plasmon resonance (SPR) instrument to evaluate the MPB events by amplifying signals from the specific target molecules. Using our MPB-based method, PD-1 antibody that forms a type of MPB by complexing with two PD-1 proteins, which are currently used for cancer immunotherapy, is detectable down to a level of 10 nM. In addition, small multivalent cations (e.g., Ca2+, Fe2+, and Fe3+) are distinguishably measurable over monovalent cations (e.g., Na+ and K+) with the pNIPAm-co-AAc nanogels.

Original languageEnglish
Pages (from-to)5413-5419
Number of pages7
JournalACS Applied Materials and Interfaces
Issue number5
Publication statusPublished - 2020 Feb 5


  • biosensor
  • hydrogel
  • label free
  • protein multivalent binding (PMB)
  • protein-protein interaction
  • surface plasmon resonance

ASJC Scopus subject areas

  • Materials Science(all)


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