A Photoactivatable BODIPY Probe for Localization‐based Super‐Resolution Cellular Imaging

The synthesis and application of a photoactivatable boron‐alkylated BODIPY probe for localization‐based super‐resolution microscopy is reported. Photoactivation and excitation of the probe is achieved by a previously‐unknown boron‐photodealkylation reaction with a single low‐power visible laser and without requiring the addition of reducing agents or oxygen scavengers in the imaging buffer. These features lead to a versatile probe for localization‐based microscopy of biological systems. The probe can be easily linked to nucleophile‐containing molecules to target specific cellular organelles. By attaching paclitaxel to the photoactivatable BODIPY, in vitro and in vivo super‐resolution imaging of microtubules is demonstrated. This is the first example of single molecule localization‐based super‐resolution microscopy using a visible‐light activated BODIPY compound as a fluorescent probe

The Intersection Between the LGBT Population and Party Affiliation

This issue brief discusses how the lesbian, gay, bisexual, and transgender population aligns with each major political party. It also outlines the main LGBT organizations of the Democratic and Republican parties and LGBT voting trends in the most recent elections

Efficient Far-Red/Near-IR Absorbing BODIPY Photocages by Blocking Unproductive Conical Intersections

Photocages are light-sensitive chemical protecting groups that give investigators control over activation of biomolecules using targeted light irradiation. A compelling application of far-red/near-IR absorbing photocages is their potential for deep tissue activation of biomolecules and phototherapeutics. Towards this goal, we recently reported BODIPY photocages that absorb near-IR light. However, these photocages have reduced photorelease efficiencies compared to shorter-wavelength absorbing photocages, which has hindered their application. Because photochemistry is a zero-sum competition of rates, improving the quantum yield of a photoreaction can be achieved either by making the desired photoreaction more efficient or by hobbling competitive decay channels. This latter strategy of inhibiting unproductive decay channels was pursued to improve the release efficiency of long-wavelength absorbing BODIPY photocages by synthesizing structures that block access to unproductive singlet internal conversion conical intersections, which have recently been located for simple BODIPY structures from excited state dynamic simulations. This strategy led to the synthesis of new conformationally-restrained boron-methylated BODIPY photocages that absorb light strongly around 700 nm. In the best case, a photocage was identified with an extinction coefficient of 124,000 M-1cm-1, a quantum yield of photorelease of 3.8%, and an overall quantum efficiency of 4650 M-1cm-1 at 680 nm. This derivative has a quantum efficiency that is 50-fold higher than the best known BODIPY photocages absorbing \u3e600 nm, validating the effectiveness of a strategy for designing efficient photoreactions by thwarting competitive excited state decay channels. Furthermore, 1,7-diaryl substitutions were found to improve the quantum yields of photorelease by excited state participation and blocking ion pair recombination by internal nucleophilic trapping. No cellular toxicity (trypan blue exclusion) was observed at 20 μM, and photoactivation was demonstrated in HeLa cells using red light

Self-Immolative Phthalate Esters Sensitive to Hydrogen Peroxide and Light

Self-immolative aryl phthalate esters were conjugated with cleavable masking groups sensitive to light and hydrogen peroxide. The phthalate linker releases the fluorescent dye 7-hydroxycoumarin upon exposure to light or H2O2, respectively, leading to an increase in fluorescence. The light-sensitive aryl phthalate ester is demonstrated as a pro- fluorophore in cultured S2 cell

Direct Photorelease of Alcohols from Boron-Alkylated BODIPY Photocages

BODIPY photocages allow release of substrates us-ing visible light irradiation. They have the drawback of requiring reasonably good leaving groups for photorelease. Photorelease of alcohols is often accomplished by attachment with carbonate linkages, which upon photorelease liberate CO2 and gen-erate the alcohol. Here, we show that boron-alkylated BODIPY photocages are capable of directly photoreleasing both aliphatic alcohols and phenols upon irradiation via photocleavage of ether linkages. Direct photorelease of a hydroxycoumarin dye was demonstrated in living HeLa cells