The University of Massachusetts Amherst

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Highly Resilient Synthetic Hydrogels with Tunable Mechanical Properties
This technology, developed by a team of polymer scientists at the University of Massachusetts Amherst, provides a versatile and simple method for producing highly resilient synthetic hydrogels with excellent mechanical properties comparable to the most efficient, naturally occurring elastic protein called resilin. The method involves the use of photo-initiated crosslinking reaction of hydrophilic and hydrophobic polymers having reactive end-groups in the presence of a tetra-functional thiol cross-linker. The resultant resilient hydrogels possess network elements of resilin, including a uniform network structure, low crosslink density, and an absence of secondary structures within the crosslinked primary chains. These hydrogels are capable of undergoing significant reversible deformation without energy loss (?97% resilience) at varying water content and show negligible hysteresis across a broad range of strains up to 300%. The swelling capacity, stiffness and fracture toughness of the hydrogels can be easily tuned by controlling the volume fractions of the hydrophilic and hydrophobic polymers to tailor the hydrogels to the specific needs of end-use applications. Current studies have focused on material elements common in extended wear contact lenses.
Published: 6/11/2021   |   Inventor(s): Gregory Tew, Melissa Lackey, Jun Cui, Catherine Walker, Alfred Crosby
Category(s): Material science, Healthcare
Cavitation Rheology for Measuring Local Mechanical Properties in Biologically Relevant Soft Materials
Measuring the mechanical properties of a complex biological tissue is crucial to developing knowledge about its physiology. Determining these physical properties in vivo is essential to innovation in tissue engineering, as well as to investigating the effects of aging and disease. Due to the heterogeneous structure of complex tissues, localized testing is necessary since probing surface properties only provides an incomplete picture of a tissue’s mechanical properties. Cavitation Rheology Technique (CRT), a novel methodology that originated in Dr. Alfred J. Crosby’s lab, succeeds where traditional techniques fall short. CRT involves measuring the pressure to induce cavitation at the tip of a needle within a soft material. This pressure is quantitatively related to the local modulus of the material. This allows for localized testing of non-transparent materials and tissues. Furthermore, CRT adopts a simple device and system design and requires only minimal amounts of sample material and testing time. This technique has been successfully demonstrated in a broad range of synthetic hydrogels and natural tissues, and can be applied in vivo.
Published: 6/11/2021   |   Inventor(s): Alfred Crosby, Jessica Zimberlin Eastman (pat agent)
Category(s): Biotechnology, Healthcare, Devices & sensors, Devices, Diagnostic technology, Material science
Reduced-Pain Syringe Needle Injection Systems
This invention provides cost-effective and user-friendly syringe needle injection systems that ease patients' discomfort during the injection operations.
Published: 9/8/2016   |   Inventor(s): Alfred Crosby, Shruti Rattan
Category(s): Healthcare, Devices
This invention provides a novel, reusable adhesive surface with a well-defined surface wrinkle pattern as well as a facile, scalable and economical method to directly fabricate a patterned adhesive using a bottom-up approach. The patterning process involves swelling a laterally confined polymer film to develop surface wrinkles and photopolymerizing the swelling agent to stabilize the wrinkles. The control of adhesion is determined by the wavelength of the surface wrinkles, which is directly proportional to the thickness of the polymer film. Various processing parameters such as the film thickness, the polymer or swelling agent material, and the degree of lateral confinement can be adjusted to tune and control adhesion to produce truly "smart" adhesives for a variety of commercial applications.
Published: 11/18/2014   |   Inventor(s): Alfred Crosby, Edwin Chan, Ryan Hayward
Category(s): Material science, Engineering, Physical Science
BUMP: BUckled Microlens Patterns for Optics and Adhesion
This technology provides a rapid, low-cost and versatile method for fabricating microlens arrays based on surface wrinkling. Surface wrinkling is a shape instability that occurs upon the application of a critical compressive stress to a material. This fabrication method uses selective surface modification and controlled swelling of an elastomeric layer to cause spontaneous formation of aligned wrinkles and microlens structures at the modified sites of the layer. The curvature of the microlens structures can be easily tuned by adjusting the size and/or the thickness of the modified sites.
Published: 2/27/2014   |   Inventor(s): Alfred Crosby, Edwin Chan
Category(s): Material science, Devices