Recent Implementations of Molecular Photoswitches into Smart Materials and Biological Systems

Abstract

Light is a nearly ideal stimulus for molecular systems. It delivers information encoded in the form of wavelengths and their intensities with high precision in space and time. Light is a mild trigger that does not permanently contaminate targeted samples. Its energy can be reversibly transformed into molecular motion, polarity, or flexibility changes. This leads to sophisticated functions at the supramolecular and macroscopic levels, from light‐triggered nanomaterials to photocontrol over biological systems. New methods and molecular adapters of light are reported almost daily. Recently reported applications of photoresponsive systems, particularly azobenzenes, spiropyrans, diarylethenes, and indigoids, for smart materials and photocontrol of biological setups are described herein with the aim to demonstrate that the 21st century has become the Age of Enlightenment—“Le siècle des Lumières”—in molecular sciences.

It's a Trap: Thiol‐Michael Chemistry on a DASA Photoswitch

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Donor-acceptor Stenhousea dducts( DASA) are popularp hotoswitches capable of togglingb etween two isomersd epending on the light and temperature of the system.T he cyclized polar form is accessed by visible-light irradiation, whereas the linear nonpolar form is recovered in the dark. [2][3][4][5] Photoswitches, such as derivatives of the donor-acceptor Stenhouse adduct (DASA), coexisti na ne quilibrium between two isomeric forms.O ne isomer consists of an intensely colored (blue, purple or orange)n onpolar linear form, whereas the other isomer is cyclized, polar,c olorless and commonly zwitterionic (Scheme 1). The thiol-Michael addition was carried out with an alkyl (1-butanethiol) and an aromatic thiol (p-bromothiophenol) as reaction partners, both in the presence of ab ase.

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Light-controllable dithienylethene-modified cyclic peptides: photoswitching the in vivo toxicity in zebrafish embryos

“…In recent years, photopharmacology [14][15][16] has emerged as a successful approach to enhance spatiotemporal selectivity of chemotherapeutics, decreasing the overall toxicity and increasing the safety of drugs. Various compound classes are currently being explored as photopharmacology agents [16][17][18][19][20][21], including peptides [19][20][21]. The idea behind photopharmacology is based on the design and use of drugs containing a reversibly photoisomerizable fragment ("molecular photoswitch") as part of their structure.…”

“…Among several known photoswitches [18] that are being used in peptides [19][20][21][22][23], diarylethenes (DAE) have increasingly attracted attention in recent years [22,23]. Photoswitchable DAEderived molecules offer several advantages for medical applications, as their photoforms are thermally irreversible and highly fatigue resistant [24][25][26].…”

“…The compound numbers are shown next to the data points. Values for the parent peptide 1 are shown as black filled circles; the original prototype 2 is color-coded in black; the data points for peptides of series i(3)(4)(5) are shown in grey, series ii (6-9) in blue, series iii(10)(11)(12)(13)(14)(15) in red, series iv(16)(17)(18) in green, and series v(19,20) in purple.…”

Sulfonated Pyrene as a Photoregulator for Single‐Stranded DNA Looping

“…Using external stimuli to regulate the conformation and thereby the functions of biomolecules could provide a way to explore cellular processes in addition to providing insight into the progression and control of various diseases, which is of growing importance in pharmacological studies . Photostimulation has an important advantage over other external stimuli, because it allows spatial and temporal control, which are well suited to the spatiotemporal characteristics of the activities of biomolecules . Therefore, photostimulation has garnered increasing attention as a highly controllable tool for the spatiotemporal regulation of biomolecules.…”