Near‐Infrared Carbonized Polymer Dots for NIR‐II Bioimaging

Abstract

Carbon dots (CDs) or carbonized polymer dots (CPDs) are an emerging class of optical materials that have exceptional applications in optoelectronic devices, catalysis, detection, and bioimaging. Although cell studies of CPDs have produced impressive results, in vivo imaging requires available CPDs to fluoresce in the near-infrared-II (NIR-II) window (1000−1700 nm). Here, a two-step bottom-up strategy is developed to synthesize NIR-CPDs that provide bright emissions in both NIR-I and NIR-II transparent imaging windows. The designed strategy includes a hydrothermal reaction to form a stable carbon core with aldehyde groups, followed by the Knoevenagel reaction to tether the molecular emission centers. This procedure is labor-saving, cost-efficient, and produces a high yield. The NIR-CPDs enable high-performance NIR-II angiography and real-time imaging of the disease degree of colitis noninvasively. This technology may therefore provide a next-generation synthesis strategy for CPDs with rational molecular engineering that can accurately tune the absorption/emission properties of NIR-emissive CPDs.

Fe‐Doped Carbon Dots as NIR‐II Fluorescence Probe for In Vivo Gastric Imaging and pH Detection

“…Carbon dots with NIR-II emission are currently a rarefied existence. To the best of our knowledge, only two papers reporting NIR-II CDs are currently available, [39,40] and CDs produced in these papers did not show pH responsibility. Li et al [39] produced NIR-II CDs by a facile hydrothermal method using watermelon as a carbon source.…”

Supramolecular Chemistry of Carbon‐Based Dots Offers Widespread Opportunities

“…The earliest report are significant opportunities to afford specific structures and/or properties for further applications, not only by starting with the appropriate reagents, but also by post-functionalization of the as-prepared nanomaterial. [14,15] Especially the choice of the precursors and reaction conditions in the bottom-up syntheses has a profound effect on the final structure and properties of CDs: surface groups, [2,16] optoelectronic and electrochemical properties, [17][18][19][20][21][22][23][24][25][26][27] chirality, [28][29][30] and so on.…”

Enhanced near-infrared light-induced photoresponse via transition of monocrystalline phase and surface reconstruction

“…Upconversion (UC) luminescent materials have been extensively used in display imaging, sensing detection, photothermal therapy, and photovoltaics because of their peculiar optical process [1][2][3][4][5][6][7] . Metal ions with the d, f orbitals can fulfill the requirement for the UC by virtue of their long-lived excited states and ladder-level configurations [8] .…”