Photochromic molecules are of great interest as light-driven molecular switches in research fields of material and life sciences. Especially, fast T-type photochromic molecules with the half-life time of the thermal back reaction (t1/2) on the order of milliseconds can change not only their color but also their physicochemical properties only under photoirradiation. Herein, we report fast Ttype photochromic crystals with the t1/2 on the order of milliseconds composed of a diarylbenzene by utilizing intramolecular CH-N hydrogen bonding interactions. Our results would lead to novel photoresponsive crystalline materials whose color and physicochemical properties can be modulated only under photoirradiation.

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The analysis of trace amounts of proteins based on immunoassays and other methods is essential for the early diagnosis of various diseases such as cancer, dementia, and microbial infections. Here, we propose a light-induced acceleration of antigen-antibody reaction of attogram-level proteins at the solid-liquid interface by tuning the laser irradiation area comparable to the microscale confinement geometry for enhancing the collisional probability of target molecules and probe particles with optical force and fluidic pressure. This principle was applied to achieve a 102-fold higher sensitivity and ultrafast specific detection in comparison with conventional protein detection methods (a few hours) by omitting any pretreatment procedures; 47–750 ag of target proteins were detected in 300 nL of sample after 3 minutes of laser irradiation. Our findings can promote the development of proteomics and innovative platforms for high-throughput bio-analyses under the control of a variety of biochemical reactions.

Diarylbenzenes (DABs) have been developed as a novel family of T-type photochromic compounds. In this work, we endeavored to predict the half-life time (t1/2) in the thermal back reaction of DABs by a screening approach. By the combination of experimental and theoretical studies, we found a good relationship between the t1/2 and the activation energy estimated by theoretical calculations. Our results would provide useful information for the design of DABs having a desired thermal stability.