Patterning Proteins to Pattern Tissues: Methodological Approaches and Application to Electrotactic Response

Abstract

The ability to spatially control the presentation of proteins on substrates is essential for investigating cellular responses to microenvironmental cues and for engineering functional biomaterials. This paper reviews and compares several protein patterning techniques, including photopatterning using quartz photomasks, digital micromirror devices (DMDs), microcontact stamping, and patterning with stencils. Each method is evaluated based on its throughput, accessibility, and suitability for generating both defined patterns. Each method was tested experimentally, and it was found that the cells were able to adhere onto substrates regardless of where the protein patterns were created for techniques that used Poly-L-lysine polyethylene glycol (PLL-g-PEG). In order to more reliably control the protein pattern and cell adhesion, physical barriers such as silicone stencils were also used to dictate the protein patterning. This allowed for easy and reliable control over the protein patterns, which enabled the electrotaxis experiment that was conducted. The protein patterned substrates are used to control the shape and size of cells to study the effect of tissue size on the response of the tissue when placed in an electric field. We found that increasing tissue size leads to an increase in the velocity of the cells along the direction of the stimulation direction, and we provide several explanations for why this phenomenon is observed.