Collaborative Research: Shape-Memory Polymers for Multiscale Force Sensing and Propagation within Biomaterials and at the Biomaterial-Cell Interface

NON-TECHNICAL SUMMARY A material that can feel force and report exactly how strong that force is, at every location within it, in real time, would advance biotechnology and medicine. It could help scientists understand how living cells push and pull on the materials around them, guide engineers developing better wound dressings and implants, and enable new sensors for disease treatment. Today, measuring these forces inside materials and at the boundary between materials and cells is difficult, because existing instruments work only at surfaces, only at the scale of individual molecules, or only after the fact, not during the dynamic processes that matter most. This project develops shape-memory polymers that sense and report mechanical force in real time, at scales spanning single molecules to the whole material. Shape-memory polymers can be changed into a stable temporary shape and then return to their original shape on cue. By incorporating force-sensing molecules into these polymers, researchers at Syracuse University, Clarkson University, and Texas A&M University produce materials that change color in proportion to the forces they experience, providing a continuous signal throughout the material and at the interface between living cells and the material. The project advances NSF’s priorities in biotechnology, materials research, and advanced manufacturing, and supports the national health, prosperity, and welfare. Anticipated outcomes include tools for real-time force monitoring in manufacturing and healthcare, new platforms to study how cells sense and respond to their mechanical environment, and new sensors for disease treatment and wound healing. The project also strengthens the American STEM workforce by expanding an annual workshop series into rural regions of New York State and Texas, placing leading-edge materials science, including printable smart polymer materials, into high school classrooms open to all Americans, and building a national pipeline of science and engineering talent. TECHNICAL SUMMARY Multiscale force generation and transduction in biomaterials and at the interface between biomaterials and biological targets is fundamental to the rational engineering and predictive design of stimuli-responsive biomaterials, a class of materials central to NSF’s priorities in biotechnology, materials research, and advanced manufacturing. Critical gaps exist in understanding how forces propagate across physical scales from nanoscale to bulk and across temporal scales from seconds to weeks. Tools for direct, real-time measurement of force states across these scales during dynamic processes are limited, as is a strategy for controlling multiscale force propagation in biomaterials and biointerfaces. This project studies mechanophore-incorporated, self-sensing shape-memory polymers (SMPs). A recently developed dynamic mechanophore (mDPAC) is incorporated into a cytocompatible polyurethane SMP platform; mDPAC reports applied force through a continuous shift in fluorescence emission wavelength, enabling force distribution mapping from molecular to material levels. The work pursues four objectives: (1) characterize biomaterial self-sensing at the nanoscale and at interfaces using surface-tethered mechanophores to establish a calibrated force-fluorescence relationship; (2) quantify bulk-scale force propagation using mechanophores physically and chemically incorporated into cast films and electrospun scaffolds; (3) develop a multiscale computational framework integrating density functional theory (DFT), steered molecular dynamics (SMD), and a continuum polymer network model to predict force transduction from polymer chains to bulk materials; and (4) design cell-responsive mechanophore-incorporated SMPs that report shape change triggered by cell-produced proteases. The strategies developed in this work are transferable to hydrogels, elastomers, and other polymer platforms relevant to biotechnology. This award reflects NSF Award ID: 2611321 | Program: 01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: James Henderson | Institution: Syracuse University, SYRACUSE, NY | Award Amount: $288,241 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2611321 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2611321.html