Abstract
The impeccable photostability of fluorescent nanodiamonds (FNDs) is an ideal property for use in fluorescence imaging of proteins in living cells. However, such an application requires highly specific labeling of the target proteins with FNDs. Furthermore, the surface of unmodified FNDs tends to adsorb biomolecules nonspecifically, which hinders the reliable targeting of proteins with FNDs. Here, we combined hyperbranched polyglycerol modification of FNDs with the β-lactamase-tag system to develop a strategy for selective imaging of the protein of interest in cells. The combination of these techniques enabled site-specific labeling of Interleukin-18 receptor alpha chain, a membrane receptor, with FNDs, which eventually enabled tracking of the diffusion trajectory of FND-labeled proteins on the membrane surface.
Highlights
Fluorescence imaging of proteins of interest requires highly specific molecular labeling with fluorescent probes, such as cyanine and rhodamine dyes, and fluorescent proteins [1,2,3], enabling visualization of the cellular localization of the proteins
We previously reported that surface modification of nanodiamonds with hyperbranched polyglycerol (HPG) significantly suppresses the nonspecific adsorption of biomolecules as well as self-aggregation [25]
We established a method that allows for specific labeling of IL18Rα expressed on the plasma membrane with fluorescent nanodiamonds (FNDs)
Summary
Fluorescence imaging of proteins of interest requires highly specific molecular labeling with fluorescent probes, such as cyanine and rhodamine dyes, and fluorescent proteins [1,2,3], enabling visualization of the cellular localization of the proteins. Since the surface is generally covered by hydrophobic groups such as graphite [28], nonspecific adsorption of various biomolecules and self-aggregation can occur through hydrophobic interactions [25] These features weaken the targeting specificity when labeling a specific single protein with an FND, distorting the obtained results. BL-tag guarantees the generation of chemically uniform FND-labeled proteins on the membrane, while the HPG surface modification can provide an ideal dispersive nature without non-specific adsorption in aqueous environments. With this strategy, we successfully labeled the Interleukin-18 receptor alpha (IL18Rα) chain expressed on the plasma membrane of human embryonic kidney 293 (HEK293) cells. The strategy opens up new avenues for cellular bioimaging of proteins
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
