How Molecular Crowding Differs from Macromolecular Crowding: A Femtosecond Mid-Infrared Pump-Probe Study

Pramod Kumar Verma, Achintya Kundu, Minhaeng Cho

Research output: Contribution to journalArticle


Crowding is an inherent property of living systems in which biochemical processes occur in highly concentrated solutions of various finite-sized species of both low (molecular crowding) and high (macromolecular crowding) molecular weights. Is molecular crowding fundamentally different from macromolecular crowding? To answer this question, we use a femtosecond mid-infrared pump-probe technique with three vibrational probes in molecular (diethylene glycol) and macromolecular (polyethylene glycol) solutions. In less crowded media, both molecular and macromolecular crowders fail to affect the dynamics of interstitial bulk-like water molecules and those at the crowder/water interface. In highly crowded media, interstitial water dynamics strongly depends on molecular crowding, but macromolecular crowding does not alter the bulk-like hydration dynamics and has a modest crowding effect on water at the crowder/water interface. The results of this study provide a molecular level understanding of the structural and dynamic changes to water and the water-mediated cross-linking of crowders.

Original languageEnglish
Pages (from-to)6584-6592
Number of pages9
JournalJournal of Physical Chemistry Letters
Issue number22
Publication statusPublished - 2018 Nov 15


ASJC Scopus subject areas

  • Materials Science(all)
  • Physical and Theoretical Chemistry

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