UMass Lowell team makes peptide nanoparticles and hydrogels that respond reversibly to CO2

Chemists at the Department of Chemistry, University of Massachusetts Lowell (T. Farrokhi, S. V. Ceballos, S. M. Silva and M. B. Ross) have used carbon dioxide as a dynamic and reversible stimulus to control matter at the nanoscale and the macroscale. The work was published on 7 November 2026 in Nature Communications. The control is based on sequence-specific peptide design, and the materials studied are peptide-functionalized nanoparticles and hydrogels nature.comNature Communicationsnature.comOpen source ↗.

Stimuli such as pH, light and electromagnetic fields already allow precise control over nanoscale interactions. Gases, the authors note, remain relatively unexplored as regulators of material behavior, although they play central roles in biology, energy and climate.

Nanoparticles: peptide sequence sets the sensitivity

Peptide-functionalized nanoparticles showed pronounced and tunable responses to CO2 across orders of magnitude changes in gas flow rate. According to the authors, the sensitivity is governed by site- and sequence-specific changes in peptide structure.

The dependence of aggregation on peptide sequence is described by six design principles. Quantitative modeling shows that the aggregation rate scales with the gas flow rate rather than with the cumulative CO2 dose nature.comNature Communicationsnature.comOpen source ↗.

Hydrogels and CO2 lithography

The gas-controlled response carries over from colloidal nanoparticles to centimeter-scale biocompatible hydrogels. These hydrogels respond to CO2 reversibly and colorimetrically.

Using this responsiveness, the team patterned a hydrogel spatially through a gas-permeable mask, with CO2 acting as the lithographic stimulus. The authors conclude that gas-mediated control can serve as a general and scalable strategy for programming responsive materials across length scales.