Living cells control what enters them and what leaves using carefully regulated transport across membrane pores made up of transmembrane proteins, which act as gatekeepers. In doing so, cells are able to assess what goes on in their environment and respond accordingly. Inspired by this function, the objective of this CAREER project is to develop unique strategies that enable the introduction of responsive pore-forming structures into polymeric vesicles. Specifically, the work aims to use tube-like macromolecules, known as core-shell bottlebrushes, to emulate the gating function of transmembrane proteins and enable a new class of materials that respond to mechanical activation, optical stimulation, changes in acidity, etc. These cell-like structures will help devise multiresponsive systems that may ultimately be capable of mimicking senses such as touch, sight, and smell. Building upon the results of this research endeavor, one can readily envision to use similar systems for applications such as targeted drug delivery, sensing, as well as active filtration devices for high-value applications. Concomitantly with these scholarly activities, community events will be used to promote STEM education to the general public and, particularly, underrepresented minorities. These activities will include initiatives that transcend the arts and sciences, encourage budding grade-school scientists to become makers, and provide graduate students with the tools to be scientific/technological global thinkers and leaders of tomorrow.
Part 2: Technical summary
The underlying goal of this research is to comprehend the crucial phenomena directing the co-assembly of blocky linear and bottlebrush (BB) amphiphilic copolymers towards the fabrication of bioinspired multiresponsive polymersomes. To this end, an integrative and directed strategy that relies on three connected aims was devised: (i) structural evaluation of amphiphilic triblock copolymers (e.g. stiffness, interdigitation, side-chain length), (ii) understanding of the co-assembly of amphiphilic linear and BB block copolymers, and (iii) bestowing of multi-stimuli-responsiveness to polymersomes by incorporating pore-forming BB triblocks in membranes using stimuli such as pH, light, and mechanical force. The numerous parameters that can be controlled in BBs, often orthogonally, such as persistence length, grafting length and density, make them especially alluring for this project. This work aims to bring about hitherto underexplored aspects of the self-assembly of complex polymeric architectures and their co-assembly with conventional linear block copolymers. The broader results of this work may be implemented in the fabrication of intricate, compartmentalized polymersomes that emulate cellular processes, but also in systems such active filtration membranes and/or targeted delivery systems that rely on on-demand cargo release. The PI will also implement several activities to encourage diversity and promote STEM universally and enhance participation of underrepresented minorities. These activities will include maker conferences and hackathons, as well as blending arts and sciences by exploiting the inherent visual appeal of stimuli-responsive materials. Promotions of global views of sciences and inclusion of active learning in curricula are amongst the other integrated objectives of this CAREER project. .
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.
