Small molecular NIR‐II dyes are highly desirable for various biomedical applications. However, NIR‐II probes are still limited due to the complex synthetic processes and inadequate availability of fluorescent core. Herein, the design and synthesis of three small molecular NIR‐II dyes are reported. These dyes can be excited at 850–915 nm and emitted at 1280–1290 nm with a large stokes shift (≈375 nm). Experimental and computational results indicate a 2:1 preferable host–guest assembly between the cucurbit[8]uril (CB) and dye molecules. Interestingly, the dyes when self‐assembled in presence of CB leads to the formation of nanocubes (≈200 nm) and exhibits marked enhancement in fluorescence emission intensity (Switch‐On). However, the addition of red carbon dots (rCDots, ≈10 nm) quenches the fluorescence of these host–guest complexes (Switch‐Off) providing flexibility in the user‐defined tuning of photoluminescence. The turn‐ON complex found to have comparable quantum yield to the commercially available near‐infrared fluorophore, IR‐26. The aqueous dispersibility, cellular and blood compatibility, and NIR‐II bioimaging capability of the inclusion complexes is also explored. Thus, a switchable fluorescence behavior, driven by host–guest complexation and supramolecular self‐assembly, is demonstrated here for three new NIR‐II dyes.
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Infectious diseases caused by pathogens are a health burden, but traditional pathogen identification methods are complex and time-consuming. In this work, we have developed well-defined, multifunctional copolymers with rhodamine B dye synthesized by atom transfer radical polymerization (ATRP) using fully oxygen-tolerant photoredox/copper dual catalysis. ATRP enabled the efficient synthesis of copolymers with multiple fluorescent dyes from a biotin-functionalized initiator. Biotinylated dye copolymers were conjugated to antibody (Ab) or cell-wall binding domain (CBD), resulting in a highly fluorescent polymeric dye-binder complex. We showed that the unique combination of multifunctional polymeric dyes and strain-specific Ab or CBD exhibited both enhanced fluorescence and target selectivity for bioimaging of Staphylococcus aureus by flow cytometry and confocal microscopy. The ATRP-derived polymeric dyes have the potential as biosensors for the detection of target DNA, protein, or bacteria, as well as bioimaging.
more » « less- Award ID(s):
- 2202747
- NSF-PAR ID:
- 10495341
- Publisher / Repository:
- MDPI
- Date Published:
- Journal Name:
- Polymers
- Volume:
- 15
- Issue:
- 12
- ISSN:
- 2073-4360
- Page Range / eLocation ID:
- 2723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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