Deuterated Water Accelerates Phase-Separated Droplet Formation and Enables Directional Motion - UTU Research Portal

A1 Refereed original research article in a scientific journal

Deuterated Water Accelerates Phase-Separated Droplet Formation and Enables Directional Motion;

Authors: Lin, Caihong; Yu, Jingjing; Qi, Dawei; Shi, Xuncheng; Niemi-Aro, Tuomas; Li, Jianwei

Publisher: American Chemical Society (ACS)

Publication year: 2026

Volume: 148

Issue: 24

First page : 24900

Last page: 24910

ISSN: 0002-7863

eISSN: 1520-5126

DOI: https://doi.org/10.1021/jacs.6c03395

Publication's open availability at the time of reporting: Open Access

Publication channel's open availability : Partially Open Access publication channel

Web address : https://doi.org/10.1021/jacs.6c03395

Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/527035236

Self-archived copy's licence: CC BY

Self-archived copy's version: Publisher`s PDF

Abstract

The spatiotemporal coordination of compartment formation and directed transport is fundamental to the cellular organization. However, replicating these coupled behaviors in fully aqueous synthetic systems remains challenging. We report an isotopic solvent signaling strategy that leverages the physicochemical differences between deuterated water (D₂O) and light water (H₂O) to control the liquid–liquid phase separation (LLPS) and motility of dynamic covalent droplets. Our system utilizes the in situ generation of cationic imine surfactants that complex with anionic macrocycles to form coacervate droplets. We demonstrate that D₂O significantly accelerates droplet formation compared to that of H₂O by promoting early association and amplifying the hydrophobic interactions associated with imine surfactants. Furthermore, by establishing a spatial H₂O/D₂O gradient, we trigger a surface-tension imbalance that drives the directional transport of droplets from D₂O-rich to H₂O-rich regions via Marangoni flow. These motile droplets can move faster than that without an isotope gradient and perform complex functions using fluorescent dyes as a demonstration. These functions include autonomous cargo transport and chemical exchange with their surroundings during migration. This work establishes isotopic substitution as a powerful and noninvasive trigger for governing supramolecular assembly and motility. It offers a new dimension for engineering adaptive, lifelike soft matter.

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Funding information in the publication:
We thank the Science and Technology Development Fund, Macau SAR (0119/2025/RIB2), the Sigrid Jusélius Foundation (Senior Researcher Fellowship for J.L.), and the Academy of Finland (Decision No.318524) for financial support. D.Q. acknowledges the financial support for his postdoctoral research from the Kvantum institute (University of Oulu). We gratefully acknowledge HiLIFE NMR unit at the University of Helsinki, a member of Instruct-ERIC Centre Finland, FINStruct, and Biocenter Finland. We also acknowledge Turku Protein Core, Turku Centre for Chemical and Molecular Analytic, and Cell Imaging and Cytometry core at the University of Turku. We thank Dr. Tassos Papageorgiou for providing imaging-related materials, Dr. Jarmo Käpylä for his support on ITC experiment, and Dr. Jouko Sandholm for technical support on FRAP experiment.