Organic semiconducting nanomaterials‐assisted phototheranostics in near‐infrared‐II biological window

Abstract

Phototheranostics conducted in the near-infrared-II (NIR-II) biological window exhibits high superiorities relative to that conducted in the first near-infrared (NIR-I) window due to higher penetration depth, higher signal-to-noise ratio of imaging, and improved maximum permissible exposure. Currently, most existing agents developed for NIR-II phototheranostics are limited to inorganic nanoparticles and small-molecule dyes, which suffer from the issues of longterm biotoxicity and poor photostability, respectively. Organic semiconducting nanomaterials (OSNs) constructed from π-conjugated organic semiconducting polymers or oligomers have unique advantages including high photostability, flexible optical features, and good biocompatibility due to the totally organic and biologically inert constituents. These advantages make OSNs more promising for in vivo phototheranostics. We here make a brief review about recent progress of OSNs-assisted phototheranostics conducted in the NIR-II biological window. NIR-II fluorescence imaging and photoacoustic imaging are mainly reviewed as diagnostic modalities to guide various treatments. Besides, multimodal phototheranostics using OSNs in NIR-II window is also described. At last, the challenges and outlook for OSNs-assisted NIR-II phototheranostics are discussed. K E Y W O R D S cancer therapy, fluorescence imaging, organic semiconducting nanoparticle, photoacoustic imaging, second near-infrared window This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Benzobisthiadiazole and Its Derivative-Based Semiconducting Polymer Nanoparticles for Second Near-Infrared Photoacoustic Imaging

“…Finally, the generated ultrasonic signals are collected by a broadband ultrasonic transducer and converted into PA images. Therefore, PA imaging not only has the advantage of the sensitive light absorption in contrast to an optical method but also has the advantage of small acoustic scattering similar to an acoustic method, and exhibits better spatial resolution and imaging depth than traditional optical imaging ( Yin et al, 2021 ).…”

Donor/π‐Bridge Manipulation for Constructing a Stable NIR‐II Aggregation‐Induced Emission Luminogen with Balanced Phototheranostic Performance**

“…[12,13] With the merits of diminished photoscattering,negligible autofluorescence and deeper detection depth, optical imaging in the second near-infrared bio-window (NIR-II, 1000-1700 nm) which was pioneered by Dai and co-workers has explicitly demonstrated superior performance in vivo bioimaging,i nc omparison with the well-researched visible or NIR-I (700-900 nm) channels. [14][15][16][17][18] As compared with the inorganic NIR-II phototheranostic materials,o rganic counterparts are definitely appealing as their easy-to-fabricated, well-defined structure/purity,and prominent biodegradation/ biocompatibility. [19][20][21][22][23][24][25] However,i ti si nevitable that those aromatic ring-fused structures tend to form clusters accompanied by intensely intermolecular p-p interactions in aque-ous solution, leading to fairly weakened fluorescence emission.…”

Donor/π‐Bridge Manipulation for Constructing a Stable NIR‐II Aggregation‐Induced Emission Luminogen with Balanced Phototheranostic Performance**

“…With the merits of diminished photoscattering, negligible autofluorescence and deeper detection depth, optical imaging in the second near‐infrared bio‐window (NIR‐II, 1000–1700 nm) which was pioneered by Dai and co‐workers has explicitly demonstrated superior performance in vivo bioimaging, in comparison with the well‐researched visible or NIR‐I (700–900 nm) channels [14–18] . As compared with the inorganic NIR‐II phototheranostic materials, organic counterparts are definitely appealing as their easy‐to‐fabricated, well‐defined structure/purity, and prominent biodegradation/biocompatibility [19–25] .…”