Targeted photoswitchable imaging of intracellular glutathione by a photochromic glycosheet sensor

Light-responsive glycosidase inhibitors: Tuning enzyme selectivity and switching factors through integrated chemical and optoglycomic strategies

Photopharmacology leverages light-responsive drugs to achieve spatiotemporal control over their activation and interactions with biological targets. This high level of precision is particularly crucial for therapeutic strategies that require sequential drug-target binding and dissociation, such as pharmacological chaperones (PCs) for lysosomal storage disorders (LSDs). PCs must tightly bind misfolded glycosidases in the endoplasmic reticulum (ER) to promote proper folding, yet efficiently dissociate in the lysosome to restore enzymatic function. Here, we demonstrate that azobenzene-equipped, photoswitchable sp2-iminosugars can fulfill these criteria by exploiting differential E-/Z-isomer interactions with aglycone-accommodating regions of target glycosidases. A diversity-oriented strategy was implemented, incorporating variations in glycomimetic portions, linkers, azobenzene substitution patterns, distal substituents, and valency to fine-tune light and temperature responsiveness. This approach yielded derivatives capable of selectively switching between α- and β-glucosidase inhibition, as well as conjugates exhibiting reversible nanomolar inhibition of human glucocerebrosidase, the dysfunctional enzyme in Gaucher disease, with remarkable switching factors under conditions that mirror the scenario at the ER and the lysosome. The results expand the scope of optoglycomics by providing a framework for designing photocommutators that enable reversible glycosidase modulation and laying the foundation for next-generation photoresponsive glycosidase inhibitors with therapeutic potential in LSDs and broader biomedical applications.

Supramolecular Synthesis of Dithienylethene-Albumin Complexes for Enhanced Photoswitching In Photoacoustic Imaging-Guided Near-Infrared Photothermal Therapy

Photoswitchable molecules can transit between two distinct isomers, enabling them to perform highly controllable imaging and therapeutic functions under certain laser irradiation. Dithienylethenes (DTEs), a class of photoswitchable molecules, exhibit strong thermal stability and high fluorescence quantum yield. However, the short excitation wavelength poses a significant challenge for the application of DTEs in photocontrolled imaging and therapy. Therefore, the development of DTE-based derivatives or hybrid materials with near-infrared (NIR) excitation is of great importance. In this study, two novel DTE derivatives are synthesized, whose closed-ring isomers exhibit strong absorption in the NIR region. Compared with a DTE derivative previously reported and commercially available ones, these two DTE derivatives show higher photoswitching efficiency and extended absorption wavelength. Notably, the supramolecular assembly between DTE derivatives and albumin confers NIR-activated photothermal switching ability on DTE molecules in aqueous solution. In addition, DTE-albumin nanoparticles are further developed to enable photoswitchable photoacoustic imaging (PAI) and photothermal therapy (PTT) for in vivo antitumor applications. Finally, by integrating a thermo-responsive free radical initiator into DTE-albumin nanoparticles, photoswitchable PTT and chemodynamic therapy (CDT) are achieved, effectively inhibiting tumor growth and preventing tumor metastasis.

Synthesis and Self-Assembling Properties of Carbohydrate- and Diarylethene-Based Photoswitchable Molecular Gelators

Carbohydrate-based low-molecular-weight gelators are interesting new materials with many potential applications. These compounds can be designed to include multiple stimuli-responsive functional groups. In this study, we designed and synthesized several chemically responsive bola-glycolipids and dimeric carbohydrate- and diarylethene-based photoswitchable derivatives. The dimeric glycolipids formed stable gels in a variety of solvent systems. The best performing gelators in this series contained decanedioic and dithienylethene (DTE) spacers, which formed gels in eight and nine of the tested solvents, respectively. The two new DTE-containing esters possessed interesting photoswitching properties and DTE derivative 7 was found to have versatile gelation properties in many solvents, including DMSO solutions at low concentrations. The gels formed by these compounds were stable under acidic conditions and tended to hydrolyze under basic conditions. Several gels were used to absorb rhodamine B and Toluidine blue from aqueous solutions. In this study, we demonstrated the rational design of molecular gelators which incorporated photoresponsive and pH responsive functions, leading to the discovery of multiple effective stimuli-responsive gelators.