Nanoparticle Probes for Super-Resolution Imaging of Transferrin Receptors

Texas Tech University, Lubbock TX

Investigators

Abstract

Nanoparticles are materials that are 100 nanometers or smaller. The behavior of nanoparticles differs from larger particles made of the same materials. The ability to study nanoparticle interactions with biological materials, such as living cells, is limited by the inability to see them using standard microscopic methods. A new class of nanoparticles, which emit blinking light, can be used to observe nanomaterials through a technique called super-resolution microscopy. These nanoparticles will enable researchers to achieve super-resolution measurements without complex instruments, under experimental conditions that are compatible with living cells and tissues. These nanoparticles will be used to investigate the distribution of transferrin receptors on living cell membranes. Transferrin receptors are proteins that allow iron ions to be transported into cells to promote grown and normal function. Understanding the distribution of transferrin receptors using nanoparticles will shed light on normal and abnormal cell growth, which has implications in tissue development in many species. Results from this research will have broad impact in the fields of biomedical engineering, chemistry, and biology. Several doctoral and undergraduate students will be trained through this project, including students from underrepresented groups. Nanoparticle interactions with cells and tissues remain a fundamental question in bioengineering. One of the most important types of interactions between nanoparticles and biological interfaces is in receptor labeling. The human transferrin receptor is a key receptor implicated in cell growth and proliferation. Understanding the spatiotemporal expression of this protein on cell surfaces has been limited by the diffraction limit of light and poor choices of luminescent probes. This project seeks to broaden understanding of interactions between fluorescence nanoparticle probes and transferrin receptor expression on tissues and cells using super-resolution microscopy. To reach these goals, a new nanoparticle probe will be developed for super-resolution microscopy on standard microscopy instruments. These nanoparticles will be highly fluorescent and produce self-blinking behavior. No photoswitching, complex optics, or buffers that preclude in vitro use are needed. Eradicating the formidable technical barriers to super-resolution will bring this approach to any research lab, thus having a transformative impact on any field where chemical information and high spatial resolution are needed. Blinking nanoparticles, coupled to transferrin receptor ligands, will be used to label live cell monolayers to demonstrate super-resolution imaging with standard microscopy methods. Imaging the spatial distribution of transferrin receptors over time will shed new light on tissue growth and a host of cross-cutting biological processes. In addition, the transport and binding of ligand-conjugated nanoparticles with a biological interface will be studied, increasing knowledge in nanomaterial interactions with living materials. Results from this research will have broad impact in the fields of biomedical engineering, chemistry, and biology. Several doctoral and undergraduate students will be trained through this project, including students from underrepresented groups. 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.