CB[8]- and triarylboron-based supramolecular organic framework for microRNA detection, tumor-targeted drug delivery, and photodynamic therapy

Supramolecular organic frameworks (SOFs) are widely used for biological detection and drug delivery. In this study, a SOF system was fabricated through the self-assembly of photosensitive triarylboron (TAB), TAB-6-methyl, and CB[8]. The maximum fluorescence emission of TAB-6-methyl was greatly enhanced and red-shifted from 560 nm to 610 nm after SOF formation. The SOF can specifically respond to a microRNA by dissembling and then combining with microRNA, which is accompanied by a fluorescence shift from 610 nm to 560 nm, thus providing a ratiometric readout for microRNA detection. The photosensitivity of TAB-6-methyl can be further improved by forming a SOF, which can be used in photodynamic therapy. By constructing another guest molecule, TAB-5-1-cRGD, we successfully embedded cRGD in the SOF system to improve its tumor-targeting ability. Moreover, we used this SOF system as a fluorescence imaging probe for targeted tumor imaging and as a drug carrier system for loading DOX to achieve combined photodynamic and chemotherapy treatment of tumors.