Bright Aggregation‐Induced‐Emission Dots for Targeted Synergetic NIR‐II Fluorescence and NIR‐I Photoacoustic Imaging of Orthotopic Brain Tumors

Abstract

Precise diagnostics are of significant importance to the optimal treatment outcomes of patients bearing brain tumors. NIR-II fluorescence imaging holds great promise for brain-tumor diagnostics with deep penetration and high sensitivity. This requires the development of organic NIR-II fluorescent agents with high quantum yield (QY), which is difficult to achieve. Herein, the design and synthesis of a new NIR-II fluorescent molecule with aggregation-induced-emission (AIE) characteristics is reported for orthotopic brain-tumor imaging. Encapsulation of the molecule in a polymer matrix yields AIE dots showing a very high QY of 6.2% with a large absorptivity of 10.2 L g cm at 740 nm and an emission maximum near 1000 nm. Further decoration of the AIE dots with c-RGD yields targeted AIE dots, which afford specific and selective tumor uptake, with a high signal/background ratio of 4.4 and resolution up to 38 µm. The large NIR absorptivity of the AIE dots facilitates NIR-I photoacoustic imaging with intrinsically deeper penetration than NIR-II fluorescence imaging and, more importantly, precise tumor-depth detection through intact scalp and skull. This research demonstrates the promise of NIR-II AIE molecules and their dots in dual NIR-II fluorescence and NIR-I photoacoustic imaging for precise brain cancer diagnostics.

Design of AIEgens for near-infrared IIb imaging through structural modulation at molecular and morphological levels

“…As an alternative, organic materials with the merits of potential biodegradability, salient biocompatibility and ease of processability, hold considerable promise for NIR-IIb imaging 18 . Despite many excellent organic fluorophores emitting at~1000 nm have been exploited [19][20][21][22] , fluorescence imaging in the NIR-IIb region is rarely reported mainly due to the shortage of suitable materials with characteristically longer emission wavelength 23 .…”

NIR‐II Fluorescent Self‐Assembled Peptide Nanochain for Ultrasensitive Detection of Peritoneal Metastasis

“…mm), spatial resolution (ca. mm), and high-tissue autofluorescence,t hereby greatly compromising the efficiencyo f tumor surgery.T he emergence of NIR-II fluorescence (1000-1700 nm) probes such as single-walled carbon nanotubes (SWCNTs), [14,15] quantum dots (QDs), [16][17][18][19] rare-earthdoped nanoparticles (RENPs), [20][21][22][23][24][25] and organic dyes [26][27][28][29] that feature deep-tissue penetration (ca. cm), high spatial resolution (ca.…”

Advanced Nanotechnology Leading the Way to Multimodal Imaging‐Guided Precision Surgical Therapy

“…[87] The development of novel optical probes with long tumor retention and high QY is urgent for precise IGS. [35,36,[90][91][92][93] Thus, probes engineered on the basis of AIE have considerable potential for precise IGS with improved surgical outcomes. [88] Organic fluorophores with AIE have showed improved brightness in solid or aggregated condition, such as the AIE NP, [34,40,41,89] a NP delivery system encapsulating AIE luminogens (AIEgens).…”