A pH-Triggered Polymer Degradation or Drug Delivery System by Light-Mediated Cis/Trans Isomerization of o-Hydroxy Cinnamates

Visible and NIR light photoactivatable o-hydroxycinnamate system for efficient drug release with fluorescence monitoring

Photoactivatable protecting groups (PPGs) have become powerful materials for controlling the activity of biologically important molecules in the biomedical field. However, designing PPGs that can be efficiently activated by biologically benign visible and NIR light with fluorescence monitoring is still a great challenge. Herein, we report o-hydroxycinnamate-based PPGs that can be activated by both visible (one-photon) and NIR (two-photon) light for controlled drug release with real-time monitoring. Thus, a photoremovable 7-diethylamino o-hydroxycinnamate group is covalently attached to an anticancer drug, gemcitabine, to establish a photoactivatable prodrug system. Upon excitation by visible (400-700 nm) or NIR (800 nm) light, the prodrug efficiently releases drug which is quantified by monitoring the formation of a strongly fluorescent coumarin reporter. The prodrug is taken up by the cancer cells and interestingly accumulates within mitochondria as determined by FACS and fluorescence microscopy imaging. Further, the prodrug demonstrates photo-triggered, dose-dependent, and temporally controlled cell death upon irradiation with both visible and NIR light. This photoactivatable system could be useful and adapted in the future for the development of advanced therapies in biomedicine.

Photoactivatable o-Hydroxycinnamic Platforms for Bioimaging and Therapeutic Release

Photoactivatable or photoremovable protecting groups (PPGs) have become a powerful material and gained enormous interest in the field of biomedical applications. PPGs have been utilized for noninvasive, on-demand, spatio-temporal controlled release of biological effectors by irradiation with light to induce biochemical function. Over the past few years, o-hydroxycinnamate (oHC)-based PPGs have received considerable attention for the release of molecules of interest by either UV (one-photon) or near-IR (two-photon) irradiation. In this miniperspective, we have summarized the development of oHC PPGs for bioimaging and the controlled release of therapeutics, bioactive volatiles and other payloads with real-time monitoring. In addition, several future perspectives of oHC systems have been highlighted at the end of this miniperspective.

Synergistic Disruption of Metabolic Homeostasis through Hyperbranched Poly(ethylene glycol) Conjugates as Nanotherapeutics to Constrain Cancer Growth

Combination therapy is a promising approach for effective treatment of tumors through synergistically regulating pathways. However, the synergistic effect is limited, likely by uncontrolled co-delivery of different therapeutic payloads in a single nanoparticle. Herein, a combination nanotherapeutic is developed by using two amphiphilic conjugates, hyperbranched poly(ethylene glycol)-pyropheophorbide-a (Ppa) (HP-P) and hyperbranched poly(ethylene glycol)-doxorubicin (DOX) (HP-D) to construct co-assembly nanoparticles (HP-PD NPs) for controllably co-loading and co-delivering Ppa and DOX. In vitro and in vivo antitumor studies confirm the synergistic effect of photodynamic therapy and chemotherapy from HP-PD NPs. Metabolic variations reveal that tumor suppression is associated with disruption of metabolic homeostasis, leading to reduced protein translation. This study uncovers the manipulation of metabolic changes in tumor cells through disruption of cellular homeostasis using HP-PD NPs and provides a new insight into the rational design of synergistic nanotherapeutics for combination therapy.