With the support of the Chemical Measurement and Imaging (CMI) Program in the Division of Chemistry, and partial funding from the Cellular Dynamics and Function Cluster in the Division of Molecular and Cellular Biosciences, Professor Ryan White of the University of Cincinnati Main Campus is studying new ways for measuring the release of small molecules at an interface with spatial resolution on the single biological cell and sub-cellular size scales. This measurement method is particularly significant in measuring cell signaling where small molecule messengers travel between cells dictating how they interact with their neighboring cells and environment. Because of the generality of the sensing method, the approach can be applied to a wide range of cell types, including non-neuronal cells in the brain. The proposed approach by Professor White and his team involves embedding a cellular membrane protein receptor, or protein channel, at the end of a nanoneedle electrode that can be placed in proximity to various interfaces for localized detection. In order the achieve this detection, the project will overcome the major challenge in protein channel measurements for analytical purposes – the ability to control and maintain a single channel through the duration of an experiment. The long-term goal of the research program is to develop probes that create “artificial synapses†to monitor the dynamics and heterogeneity of the cell membrane and cellular microenvironment. The work will provide broad impact in measurement science and new knowledge in the measure of cellular communication in the brain. This impact will reach a diverse group of students and scientists through the development of a program targeting the increased and sustained participation of first-generation college students in undergraduate research, through the creation of a strong community and culture.
The overarching goal of this proposal is to develop nanoscale ion channel probes for imaging and localized molecular and ion sensing at interfaces with high spatial resolution (nanometer-micrometer). The impactful research will expand localized detection abilities to analytes that are not accessible with current methodologies, because the analytes are neither optically nor electrochemically active. This need is particularly significant in measuring cell signaling where messengers travel between cells, dictating how they interact with their environment. The measurements enabled by the new method will facilitate discoveries of how astrocytes, with contacts to the neurovascular system and neurons, differentially signal between the two which is critical for networked communication in the brain. Currently, however, there is a lack of generalizable tools that can measure molecules localized at a cell surface. The use of ion channel probes for scanning ion conductance microscopy (SICM), where protein channels are embedded in a lipid bilayer at the end of a probe, is a promising method to leverage ion channel activity for ion and molecular detection with the imaging capabilities of SICM. However, major hurdles exist that hinder their use. To overcome these challenges, Professor White and his team will develop a new SICM imaging mode that employs metal nanoneedle probes that support ion channel measurements with dramatically reduced probe size over existing approaches for localized detection at interfaces. They will demonstrate the ability to perform localized detection on test-bed inorganic substrates and the surface of astrocyte cells. These measurements are anticipated to enable the first direct, localized detection of adenosine triphosphate (ATP) release from astrocytes. The broader impacts of the work lie in the ability of the proposed measurement method to provide new knowledge about how biological systems (single cells, tissue slices) communicate via the release of small molecules. This impact will reach a diverse group of students and scientists through the development of a "Pathway to Undergraduate Research" program that targets increased and sustained participation of first-generation college students in undergraduate research through the creation of a strong community and culture.
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.
