About

Steve Granick is the Robert K. Barrett Professor at the University of Massachusetts Amherst in the Department of Polymer Science and Engineering. His current research projects include active polymers, molecules in extreme environments, biological intelligence, and memory of non-neural cells. As a faculty member, he is involved in advancing the understanding of complex polymer systems and their applications, contributing to the fields of polymer science and engineering.

Research topics

• Chemistry

Selected publications

• Observation of chemically-driven force fluctuations in an optical trap

  Zenodo (CERN European Organization for Nuclear Research) · 2026-01-02

  datasetOpen accessSenior author

  This dataset includes measurements involving optical tweezers, NMR, and controls to support the paper "Observation of Chemically-Driven Force Fluctuations in an Optical Trap." The data files can be opened using text, Mestrenova, or Excel.

  PublisherDOI

• Observation of chemically-driven force fluctuations in an optical trap

  Zenodo (CERN European Organization for Nuclear Research) · 2026-01-02

  datasetOpen accessSenior author

  This dataset includes measurements involving optical tweezers, NMR, and controls to support the paper "Observation of Chemically-Driven Force Fluctuations in an Optical Trap." The data files can be opened using text, Mestrenova, or Excel.

  PublisherDOI

• Electric spiking activity in epithelial cells

  Proceedings of the National Academy of Sciences · 2025-03-17 · 7 citations

  articleOpen accessSenior authorCorresponding

  Epithelial cells (human keratinocyte cells and the canine MDCK cell line), traditionally viewed as electrically non-self-excitable and involved primarily in physiological functions such as barrier presentation, absorption, secretion, and protection, are shown here to exhibit traveling extracellular electric charge when they recover from spatially focused, laser-induced wounding of confluent monolayers cultured on a multielectrode array chip. Voltage spikes measured on these electrodes display depolarization, repolarization, and hyperpolarization phases with amplitudes similar to the action potentials of neurons but with the markedly slower duration of 1 to 2 s. Some propagate distances up to hundreds of μm from the wound with a mean speed of around 10 mm s −1 . Generation and transmission of bioelectric signals are significantly influenced by the perturbation of mechanosensitive cationic ion channels. These direct measurements confirm bioelectric signaling that previous work has hypothesized to regulate epithelial cell development and may have relevance to the frequency parameter selection of bioelectric devices.

  PublisherOA PDFDOI

• Aqueous Ion Mobility over a Broad Concentration Range

  Physical Review Letters · 2025-06-11 · 2 citations

  article

  For concentrations between dilute and the highly concentrated limit of almost 5 M, we compare our explicit-water molecular dynamics simulations of LiH_{2}PO_{4} (which dissociates into H_{2}PO_{4}^{-} anions relevant to biochemical processes and Li^{+} cations relevant to battery technology) to our pulsed-field gradient NMR measurements of ion diffusion, and find compensation between electrostatic and osmotic forces. The significance is that, noticing that the Kirkwood equation holds when using its exact solution but seemingly is violated when making the traditional approximation of using total force relaxation time in place of the memory relaxation time, we explain slower translational diffusion with increasing ion concentration as a dynamical effect arising from growing memory relaxation time. Physically, 2 orders of magnitude separate the timescales of electrostatic and osmotic forces from the total force such that dynamical correlations between force components lead to concentration-independent total force variance and force relaxation time.

  PublisherDOI

• Cells lining your skin and organs can generate electricity when injured − potentially opening new doors to treating wounds

  2025-03-17

  preprintSenior author
  PublisherDOI

• The ergodicity question when imaging DNA conformation using liquid cell electron microscopy

  Proceedings of the National Academy of Sciences · 2024-01-09 · 10 citations

  articleOpen accessSenior authorCorresponding

  Assessing the ergodicity of graphene liquid cell electron microscope measurements, we report that loop states of circular DNA interconvert reversibly and that loop numbers follow the Boltzmann distribution expected for this molecule in bulk solution, provided that the electron dose is low (80-keV electron energy and electron dose rate 1–20 e − Å −2 s −1 ). This imaging technique appears to act as a “slow motion” camera that reveals equilibrated distributions by imaging the time average of a few molecules without the need to image a spatial ensemble.

  PublisherOA PDFDOI

• Fourier Law Fidelity Contrasted by Infrared Imaging as Heat Flows through Metals and Polymers

  The Journal of Physical Chemistry C · 2024-07-19 · 1 citations

  articleSenior authorCorresponding

  Using a home-built imaging system to map by infrared detection the surface temperature of a metallic material, we fail to confirm the generality of previously reported deviations, for translucent polymers and quartz, from Fourier’s law at the macroscale. This discrepancy is explained by the fact that unlike polymers and quartz, metals are optically opaque. Comparing the environments of air and vacuum quantitatively, we show the advantage of the latter environment. Of special interest is that thermal gradients reveal surface features otherwise concealed under uniform temperature conditions. Our findings not only confirm the classical heat conduction model for metal but also highlight the often-overlooked impact of material optical properties on thermal behavior.

  PublisherDOI

• Exceptions to Fourier’s law at the macroscale

  Proceedings of the National Academy of Sciences · 2024-03-05 · 6 citations

  articleOpen accessSenior authorCorresponding

  The usual basis to analyze heat transfer within materials is the equation formulated 200 years ago, Fourier's law, which is identical mathematically to the mass diffusion equation, Fick's law. Revisiting this assumption regarding heat transport within translucent materials, performing the experiments in vacuum to avoid air convection, we compare the model predictions to infrared-based measurements with nearly mK temperature resolution. After heat pulses, we find macroscale non-Gaussian tails in the surface temperature profile. At steady state, we find macroscale anomalous hot spots when the sample is topographically rough, and this is validated by using two additional independent methods to measure surface temperature. These discrepancies from Fourier's law for translucent materials suggest that internal radiation whose mean-free-path is millimeters interacts with defects to produce small heat sources that by secondary emission afford an additional, non-local mode of heat transport. For these polymer and inorganic glass materials, this suggests unique strategies of heat management design.

  PublisherDOI

• Solid-body trajectoids shaped to roll along desired pathways

  Nature · 2023-08-09 · 11 citations

  article
  PublisherDOI

• Phosphorescent extensophores expose elastic nonuniformity in polymer networks

  Nature Communications · 2023-02-01 · 11 citations

  articleOpen accessSenior authorCorresponding

  Networks and gels are soft elastic solids of tremendous technological importance that consist of cross-linked polymers whose structure and connectivity at the molecular level are fundamentally nonuniform. Pre-failure local mechanical responses are not understood at the level of individual crosslinks, despite the enormous attention given to their macroscopic mechanical responses and to developing optical probes to detect their loci of mechanical failure. Here, introducing the extensophore concept to measure nondestructive forces using an optical probe with continuous force readout proportional to deformation, we show that the crosslinks in an elastic polymer network extend, fluctuate, and deform with a wide range of molecular individuality. Requiring little specialized equipment, this foundational single-molecule phosphorescence approach, applied here to polymer science and engineering, can be useful to a broad science and engineering community.

  PublisherOA PDFDOI

Recent grants

• Polymer Dynamics at Surfaces and in Complex Media

  NSF · $366k · 2006–2010

• In Situ Imaging and Spectroscopy of Tribological Contacts

  NSF · $318k · 2006–2011

• Rotation Diffusion of MOON Particles

  NSF · $312k · 2009–2013

• Polymer Dynamics at Interfaces and in Complex Environments

  NSF · $790k · 2009–2015

Frequent coauthors

• Sung Chul Bae

  Ulsan National Institute of Science and Technology

  132 shared

• Yoon‐Kyoung Cho

  Seoul National University

  62 shared

• Stephen M. Anthony

  Sandia National Laboratories California

  46 shared

• Erik Luijten

  Northwestern University

  41 shared

• Yingxi Zhu

  35 shared

• Tsvi Tlusty

  Institute for Basic Science

  34 shared

• Huan Wang

  Beijing National Laboratory for Molecular Sciences

  34 shared

• Jing Yan

  Yale University

  28 shared

Labs

• Steve Granick's LabPI

  Develop and exploit simple, creative, and novel design paradigms that will change the way scientists, engineers, and the general public use and understand materials.

Education

• Ph.D., Physics

  University of California, Berkeley

  1982

• B.S., Physics

  University of California, Los Angeles

  1977