Excellence in Research: Stimuli-Responsive Exosomes for Quantitative Biosensing

Exosomes are a category of lipid-bound, nanosized vesicles ( small sacs formed by a membrane and filled with liquid) produced by most cells in the body. Due to the nature of their packaging and release, these vesicles can contain molecules that are characteristic of their cells of origin. This means that exosomes can carry biomarkers for various disease states, including cancer and Alzheimer’s disease. However, current methods for isolating and purifying exosomes are costly and often ineffective. Developing new ways to control the release of exosome contents is essential to engineer better diagnostic tests. This project will investigate a new set of knowledge and develop tools to control the behavior of exosomes through the application of heat. Students participating in this multidisciplinary research will be mentored and trained to prepare them for a successful career in STEM through summer research experiences, conferences, and hands-on lab experiences. The goal of this Historically Black Colleges and Universities - Excellence in Research (HBCU-EiR) project is to develop and investigate the potential for engineering thermo-sensitive liposomes for applications in biosensing and downstream diagnostic applications. This will address a critical challenge in the field, which is to exert selective control over specific exosome populations within a mixed sample. More specifically, the ability to direct the release of a subset of exosomes from a capture substrate and to discharge their intra-vesicular cargo in a reliable and highly controlled manner could replace burdensome purification and isolation protocols and broaden the technological toolbox for integrated biosensors. Inspired by recent success in engineering stimuli-responsive liposomes, the investigators propose a new paradigm in the field of exosome research. Studies are designed to test the hypothesis that exosomes can be optimized to exhibit controllable behavior (e.g., release cargo) when exposed to an external stimulus (e.g., temperature). Ultimately, the project aims to define the criteria for achieving differential release in two distinct scenarios (1) from release of a 2D captured substrate and (2) from release of intra-exosomal contents (or target analytes). This will be accomplished via the following objectives: (1) Determine whether compositional differences in cell-derived model exosomes can be used to incite stimuli-responsive behavior; and (2) Engineer thermo-responsive exosomes by selective surface modification and validate their potential for biosensing applications. These outcomes are expected to advance and transform how exosomes and other extracellular vesicles are manipulated in many settings by introducing a new mechanism to control their behavior selectively. The relevance of this work additionally lies in the potential to define and test proof-of-concept criteria for other stimuli-responsive technologies, including light, enzymes, and acoustics. This will open pathways for opportunities to advance the quantification, monitoring, and detection of any targets bound in exosomes and capabilities with high relevance to the biosensing community. 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.