The self-labeling protein SNAP-tag is commonly used to study the expression and functions of proteins of interest (POI) in live cells. It undergoes a specific reaction with synthetic probes containing a benzylguanine (BG) moiety. Despite the fact that many substrates for SNAP-tag have been developed, photofunctional substrates that serve as both fluorogenic probes and singlet oxygen (1O2) photosensitizers have not been reported. Herein, we report the design of a new class of phosphorogenic iridium(III) nitrone complexes for these purposes. In this strategy, a strained alkyne-modified substrate BCN-BG was used to label SNAP-tag, which was then reacted with the iridium(III) nitrone complexes. These complexes were weakly emissive with negligible 1O2 generation due to efficient quenching of the nitrone moiety. However, they displayed significant emission enhancement (I/Io) upon reactions with the strained alkyne BCN-OH (I/Io = ca. 7.2 – 47.1) and BCN-modified BSA (I/Io= ca. 82.9 – 327.1). These reactions also resulted in excellent photoinduced 1O2 generation (generation quantum yields up to 0.91). Confocal images revealed that CHO-K1 cells expressing organelle-specific SNAP-tag exhibited intense and long-lived emission only upon treatment with both BCN-BG and the complexes. MTT assays indicated that BCN-BG and SNAP-tag significantly increased the photocytotoxicity of the complexes, resulting in a photocytotoxicity index up to 115.9. We believe that this two-step labeling approach will lead to the development of new theranostic applications.

Modulation of Emission and Singlet Oxygen Photosensitization in Live Cells Utilizing Bioorthogonal Phosphorogenic Probes and Protein Tag Technology

In order to view the entire gallery of posters, videos, and other materials, please click "Submissions" below.

To find the Q&A for each poster category, please click "Sessions" below. To ask a question, simply click on the category session; they are organized alphabetically by title. After clicking, you'll see a list of video presentations in the list to the right. Below each video area, you'll see a section entitled 'Q&A for this presentation:'. Here you'll be able to post questions to the authors. They'll be notified, and you'll also be notified when they reply to your question. You can expect that notification by email, and you'll find the author's response here. 

ACS Publications Symposium

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.