Long-wavelength photoremovable protecting groups: On the way to in vivo application

Photoremovable protective groups (PPGs) and related caged compounds have been recognized as a powerful tool in an arsenal of life science methods. The present review is focused on recent advances in design of caged compounds which function in red or near-infrared region. The naive comparison of photon energy with that of organic bond leads to the illusion that long-wavelength activation is possible only for weak chemical bonds like N-N. However, there are different means to overcome this threshold and shift the uncaging functionality into red or near-infrared regions for general organic bonds. We overview these strategies, including the novel photochemical and photophysical mechanisms used in newly developed PPGs, singlet-oxygen-mediated photolysis, and two-photon absorption. Recent advances in science places the infrared-sensitive PPGs to the same usability level as traditional ones, facilitating in vivo application of caged compounds. (C) 2019 The Authors. Published by Elsevier B.V. on behalf of Research Network of Computational and Structural Biotechnology.