Laura Bradley and Sarah Perry
Co-organizers of the UMass-3M Diversity in STEM Lecture Series
Microgels and hydrogels have expanded the field of soft matter. They have been built into materials for cosmetic products, biomaterials, food packaging and additives, and oil refinement. In our lab, we synthesize microgels and hydrogels to develop biomaterials from polymers that are highly sensitive to external stimuli, such as pH, temperature, or ionic solvent content. These external factors induce drastic changes to their phase behavior and cause them to reversibly change volume by absorbing and releasing the aqueous solvent that they are swollen in. Hair is a natural polymeric composite material and is one of the key characteristics that classify us as mammals. Much like our bodies, our hair tresses need water and nutrients to maintain hair health and appearance. The inner cortex of each of our hair fibers is composed of tight bundles of keratin protein. Very much like synthetic microgels and hydrogels, these natural protein keratin bundles are highly responsive to external stimuli, and they also absorb and expel water according to changes in the pH, temperature, and ionic solvent content. This presentation illustrates how our lab uses stimuli responsive microgels and collagen I hydrogels to create tunable 3D-biocomposite cell scaffolds to study malignant cell behavior. This project began with comparing NIH/3T3 fibroblast infiltration among poly n-isopropylacrylamide colloidal microgel particles and collagen I hydrogels (0.5%). Initial qualitative results showed that the fibroblasts formed large spheroids among the suspension of microgel particles, while in the collagen I hydrogels, the fibroblasts appeared more circular and isolated. This presentation will also include a discussion on how we use the principles that dictate the material properties of hydrogels to analyze the surface chemistry of textured hair. Our journey in studying textured hair began virtually by employing the critically appraised topic (CAT) methodology to conduct qualitative research on a topic related to understanding the chemistry of textured hair. Several students used the technique to investigate how hydration, surfactants, hair dyes and pigments, and topical aseptic creams affect the surface chemistry, disulfide bond distribution, and growth of hair fibers. All research was and continues to be performed by our Spelman undergraduate students, which provides them with the opportunity to engage in polymer science research, develop transferrable skills, and advance the field of surface science.