Advancements in organic fluorescent materials: unveiling the potential of peripheral group modification in dithienyl-diketopyrrolopyrrole derivatives for one- and two-photon bioimaging

Abstract

The quest for novel organic fluorescent materials capable of two-photon absorption (2PA) has intensified in recent years due to their promising applications in biological imaging. Two-photon fluorescence microscopy (2PFM) offers high spatial-temporal resolution, reduced photodamage, and deeper tissue penetration compared to conventional techniques. However, the development of bright two-photon molecular markers remains a challenge, necessitating compounds with high fluorescence quantum yield and 2PA cross-section (σ2PA). Strategies such as increasing π-conjugation have shown promise but are hindered by synthesis complexities and limited biocompatibility. Alternatively, incorporating electron-donating (ED) or electron-withdrawing (EW) peripheral groups in a main structure has emerged as a viable approach, leading to significant enhancements in σ2PA. This study highlights the advantages and challenges of these strategies, emphasizing the importance of exploring new organic compounds and evaluating the efficacy of peripheral groups for advanced two-photon bioimaging applications.