Cell Membrane‐Camouflaged NIR II Fluorescent Ag₂Te Quantum Dots‐Based Nanobioprobes for Enhanced In Vivo Homotypic Tumor Imaging

Abstract

The advantages of fluorescence bioimaging in the second near‐infrared (NIR II, 1000–1700 nm) window are well known; however, current NIR II fluorescent probes for in vivo tumor imaging still have many shortcomings, such as low fluorescence efficiency, unstable performance under in vivo environments, and inefficient enrichment at tumor sites. In this study, Ag2Te quantum dots (QDs) that emit light at a wavelength of 1300 nm are assembled with poly(lactic‐co‐glycolic acid) and further encapsulated within cancer cell membranes to overcome the shortcomings mentioned above. The as‐prepared ≈100 nm biomimetic nanobioprobes exhibit ultrabright (≈60 times greater than that of free Ag2Te QDs) and highly stable (≈97% maintenance after laser radiation for 1 h) fluorescence in the NIR II window. By combining the active homotypic tumor targeting capability derived from the source cell membrane with the passive enhanced permeation and retention effect, improved accumulation at tumor sites ((31 ± 2)% injection dose per gram of tumor) and a high tumor‐to‐normal tissue ratio (13.3 ± 0.7) are achieved. In summary, a new biomimetic NIR II fluorescent nanobioprobe with ultrabright and stable fluorescence, homotypic targeting and good biocompatibility for enhanced in vivo tumor imaging is developed in this study.

Recent Progress in NIR-II Contrast Agent for Biological Imaging

“…Other recent representative work includes the development of Ag 2 Te quantum dots by Zhang et al (2019), which can emit fluorescence at 1,300 nm wavelength after assembly. The assembly process is divided into two steps; first, polymerization is conducted with polylactic-co-glycolic acid (PLGA), and second, further packaging is completed with the cancer cell membrane.…”

NIR-quantum dots in biomedical imaging and their future

“…The QDs can have targeting agents added to the surface; this can take the form of small molecules (Ge et al, 2019), peptides (Li et al, 2020;Tang et al, 2015), proteins (Le et al, 2020;Sarkar et al, 2020), or antibodies (Yu et al, 2019). The QDs can also be incorporated into larger systems (Zhang et al, 2019b), such as cell vesicles, that have targeting agents on the surface and act as carriers of the QDs.…”

“…This shows that coating in the membrane of 4T1 cells can be used to target 4T1 tumors as expected, as many of the proteins are ''self-targeting.'' However, the question of whether this can be applied as a generic tumor targeting coating remains, and this may be where the simple PEG coating remains a more effective route to production of generic contrast agents rather than bespoke (Zhang et al, 2019b). The mouse was intravenously injected with the mixture of CD11b@NIR-IIa QDs and Gr-1@NIR-IIb QDs nanoprobes and was imaged at different time points with 808 nm excitation and 980 nm LP plus 1200 nm SP emission filters for NIR-IIa channel and 980 nm LP plus 1500 nm LP emission filters for NIR-IIb channel.…”

Applications of nanotechnology in virus detection, tracking, and infection mechanisms

“…Due to the limitations of current bioimaging techniques, tracking a single virus in vivo in real time is still a challenge. Recently, near‐infrared QDs with emission ranges of 800–1600 nm were synthesized and are of particular interest in the production of ~2 nm size ultra‐small near‐infrared QDs via quasi biosynthesis (Hong et al, 2012; Jiang et al, 2012; J. J. Zhang et al, 2019; M. Zhang, Yue, et al, 2018).…”