Amino-Acid-Based Metallo-Hydrogel That Acts like an Esterase

Kousik Gayen, Kingshuk Basu, Dipayan Bairagi, Valeria Castelletto, Ian W. Hamley, Arindam Banerjee

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


A histidine-based amphiphile containing a C14 fatty acyl chain, N-histidyl N′-myristry ethyl amine (AM1, 14.7 mM) forms hydrogels in the presence of Fe3+ (within the range 1.47 to 4.41 mM) and Hg2+ (within the range 3.67 to 11.02 mM) ions in aqueous dispersions at pH 6.6 (27 °C). The imidazole ring of the histidine residue plays a vital role to interact with these metal-ions. The thermal and mechanical stability of these metallo-hydrogels can be tuned by changing the proportion of amphiphile to metal ion ratio (1:0.1 to 1:0.3 for Fe3+-containing gel and 1:0.25 to 1:0.75 for Hg2+-containing gel). The metallo-hydrogels were characterized by different spectroscopic and microscopic techniques, low- A nd wide-angle powder X-ray diffraction, and small-angle X-ray scattering studies. FT-IR and NMR spectroscopic studies indicate the participation of the imidazole ring in metal-ion binding. Low- A nd wide-angle powder X-ray diffraction and small-angle X-ray scattering data are in favor of a layered structure of the supramolecular assembly of the AM1 in the presence of metal-ions. Both, the amphiphiles and the metal ion induced hydrogels reveal catalytic activity of p-nitrophenyl esters hydrolysis for the acetyl, n-butyl and n-octyl esters. Ferric ion containing metallo-hydrogel exhibits higher catalytic activity than the corresponding AM1 aggregate in the absence of metal ions.

Original languageEnglish
Pages (from-to)1717-1724
Number of pages8
JournalACS Applied Bio Materials
Issue number5
StatePublished - 19 Nov 2018
Externally publishedYes


  • ester hydrolysis
  • esterase activity
  • histidine-based amphiphile
  • metallo-hydrogel
  • self-assembly

ASJC Scopus subject areas

  • Biomaterials
  • Chemistry (all)
  • Biomedical Engineering
  • Biochemistry, medical


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