Photosensitive protective groups are chromophores used for their ability to absorb light at specific wavelength and release the protected molecule. Initially developed for simple protective group chemistry, these probes have more efficiently been used to photo-protect (process better known as caging) the biological molecules at functional groups such as carboxylic acids, alcohols and amines. During last four decades, various chemical probes (named as DEAC450-, CDNI-, DMNB- and RuBi) have been synthesized to protect various biomolecules of interest such as glutamate, GABA, calcium, ATP and cAMP. Such caged conjugates are capable of absorbing either one-photon or two-photon light or both and thus resulting in vitro or in vivo release of activated biomolecule through spatial and temporal control. The uncaging efficiency of any caging probe depends on collective physiochemical properties such as UV-spectrum (λmax), 1P molar extinction coefficient (ε), 2P cross section (σ; unit GM). Additionally, probes are desired to have high quantum yield of photo uncaging (Φ), which is defined as the number of molecules uncaged for every photon absorbed per unit time. In this project, a new caging probe (DEAC-NST) was developed with high efficiency to absorb blue light with high 1P-extinction coefficient (ε &gt; 50,000) as well as absorbance in green light (λ510nm = 62% absorbance). DEAC-NST was synthesized in moderate yields through multi-step synthesis using various protection-deprotection strategies and heck-cross coupling. All intermediates and final products were isolated either by normal phase flash chromatography or preparatory HPLC with high purity. Synthesized molecules were characterized by HR-MS, 1H and 13C NMR. The single photon photolysis was performed by blue laser and the photolyzed metabolized were characterized by HPLC and mass spectroscopy. Caging probe was able to release a small molecule at tertiary amine in blue light with high uncaging efficiency (εΦ) of 5000.

Development of long-wavelength caging chromophore and uncaging with visible light

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.