I-Corps: Meso-indentation System for Ultra-soft Biomaterials

The broader impact/commercial potential of this I-Corps project is a system to characterize soft materials mechanically. Mechanical characterization of ultra-soft materials on the meso-scale is critical for tissue engineering scaffolds, structural and packaging materials, foams and adhesives, detergents and cosmetics, paints, food additives, lubricants, and fuel additives. However, the current mechanical characterization technique for soft and ultra-soft materials relies heavily on tensile testing. The main limitations are 1) high standard deviation due to difficulty preparing uniform samples, 2) sample damage after testing, and 3) inability to measure viscous liquid materials. The unique advantage of this meso-indentation methodology is the ability to capture mechanical properties during indentation pull-on and pull-off events of ultra-soft materials. Another novelty of the presented testbed is the in-situ visualization of adhesion events through a light sensor. Therefore, this tool can improve processing time in manufacturing biomimetic cardiac patches, control the quality, and improve the functional safety for implantation by documenting successful tissue scaffolds in manufacturing. Beyond that, this tool also has potential applications in food production, automotive oil production, and aerospace industries. This I-Corps project is based on developing a system capable of accurate mechanical performance characterizations for soft and ultra-soft materials on the centimeter scale. It comprises an adaptor attached to the mechanical load frame actuator, an indenter probe holder, a polymer-based indenter probe, a sample holder disposed below the indenter probe and configured to hold the soft and ultra-soft material, and a light sensor. The unique advantages of this system include 1) the ability to capture adhesion forces and in-situ adhesion events, 2) the elastic modulus range that concerns this testing methodology ranges from 0.5 kPa to 40 MPa, and 3) adaptability to conventional tabletop mechanical frames. Beyond that, this proprietary method works for a wide range of biomimetic materials, such as solids, semi-solid, and liquid forms, with anisotropic and heterogeneous properties. For tissue engineering, the acquired data will provide critical benchmarking values and evaluate the feasibility of biomaterials or bio-constructs for tissue therapies. For example, it can effectively improve the quality of cardiac patches by guiding the compatibility of mechanical properties between native and artificial materials. It also limits complications, enhancing functional performances, improving maturation, and reducing cardiac patients' hospitalization. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.