1,722,493 research outputs found
Spatiotemporal Control Over Circadian Rhythms With Light
Full text linkABSTRACT Circadian rhythms are endogenous biological oscillators that synchronize internal physiological processes and behaviors with external environmental changes, sustaining homeostasis and health. Disruption of circadian rhythms leads to numerous diseases, including cardiovascular and metabolic diseases, cancer, diabetes, and neurological disorders. Despite the potential to restore healthy rhythms in the organism, pharmacological chronotherapy lacks spatial and temporal resolution. Addressing this challenge, chrono‐photopharmacology, the approach that employs small molecules with light‐controlled activity, enables the modulation of circadian rhythms when and where needed. Two approaches—relying on irreversible and reversible drug activation—have been proposed for this purpose. These methodologies are based on photoremovable protecting groups and photoswitches, respectively. Designing photoresponsive bioactive molecules requires meticulous structural optimization to obtain the desired chemical and photophysical properties, and the design principles, detailed guidelines and challenges are summarized here. In this review, we also analyze all the known circadian modulators responsive to light and dissect the rationale following their construction and application to control circadian biology from the protein level to living organisms. Finally, we present the strength of a reversible approach in allowing the modulation of the circadian period and the phase
Visible and near-infrared light-induced photoclick reactions
No full textPhotoclick reactions combine the advantages offered by light-driven processes, that is, non-invasive and high spatiotemporal control, with classical click chemistry and have found applications ranging from surface functionalization, polymer conjugation, photocrosslinking, protein labelling and bioimaging. Despite these advances, most photoclick reactions typically require near-ultraviolet (UV) and mid-UV light to proceed. UV light can trigger undesirable responses, including cellular apoptosis, and therefore, visible and near-infrared light-induced photoclick reaction systems are highly desirable. Shifting to a longer wavelength can also reduce degradation of the photoclick reagents and products. Several strategies have been used to induce a bathochromic shift in the wavelength of irradiation-initiating photoclick reactions. For instance, the extension of the conjugated π-system, triplet-triplet energy transfer, multi-photon excitation, upconversion technology, photocatalytic and photoinitiation approaches, and designs involving photocages have all been used to achieve this goal. Current design strategies, recent advances and the outlook for long wavelength-driven photoclick reactions are presented.</p
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