An Activatable NIR‐II Nanoprobe for In Vivo Early Real‐Time Diagnosis of Traumatic Brain Injury

Abstract

Traumatic brain injury (TBI) is one of the most dangerous acute diseases resulting in high morbidity and mortality. Current methods remain limited with respect to early diagnosis and real‐time feedback on the pathological process. Herein, a targeted activatable fluorescent nanoprobe (V&A@Ag2S) in the second near‐infrared window (NIR‐II) is presented for in vivo optical imaging of TBI. Initially, the fluorescence of V&A@Ag2S is turned off owing to energy transfer from Ag2S to the A1094 chromophore. Upon intravenous injection, V&A@Ag2S quickly accumulates in the inflamed vascular endothelium of TBI based on VCAM1‐mediated endocytosis, after which the nanoprobe achieves rapid recovery of the NIR‐II fluorescence of Ag2S quantum dots (QDs) owing to the bleaching of A1094 by the prodromal biomarker of TBI, peroxynitrite (ONOO−). The nanoprobe offers high specificity, rapid response, and high sensitivity toward ONOO−, providing a convenient approach for in vivo early real‐time assessment of TBI.

Tumor Microenvironment‐Activated NIR‐II Nanotheranostic System for Precise Diagnosis and Treatment of Peritoneal Metastasis

“…However, the fluorescence is rapidly turned on under acidic conditions by the protonation of the imidazole groups of Fmoc‐His and DOX, which weakens their metal‐coordination and hydrophobic interactions, respectively, resulting in FEAD1 disassembly and loss of FRET. Such an activatable nanotheranostic system offers several salient features: 1) as a typical hallmark of solid tumors, the low pH property of the TME means that FEAD1 could act as a general nanotheranostic system for diagnosing and treating a broad range of tumors; 2) the NIR‐II fluorescence “turn‐on” strategy greatly improves tissue‐penetration depth and tumor‐to‐background ratio (TBR), achieving rapid diagnosis with high sensitivity; 3) TME‐activated drug release maintains DOX in stealth mode in healthy tissues while initiating burst release at tumor sites, dramatically improving therapeutic efficiency and minimizing side‐effects; 4) FEAD1 exhibits reasonable biocompatibility and low immunogenicity. Herein we show that upon intraperitoneal (IP) injection, tumor nodules of peritoneal metastasis are specifically lit‐up to allow high‐TBR NIR‐II fluorescence imaging.…”

Application of Zero-Dimensional Nanomaterials in Biosensing

“…After intravenous injection, A1094 was bleached by the TBI precursor biomarker peroxynitrite (ONOO − ), achieving rapid recovery of Ag 2 S QDs fluorescence. This NIR-II in vivo turn-on sensing and imaging strategy indicated a broad prospect of QDs fluorescence imaging in clinical applications (Li et al, 2020).…”

“…(E) The timespan of NIR-II fluorescence in brain vascular injury and healthy mice at different time points after injection of V@Ag 2 S, V&A@Ag 2 S, and A@Ag 2 S. (F) Time-dependent signal-to-noise ratio (SNR) changes determined by the NIR-II fluorescence imaging of mice after various treatments. Reproduced with permission fromLi et al (2020). Copyright 2020, Wiley-VCH.…”

Engineered Near‐Infrared Fluorescent Protein Assemblies for Robust Bioimaging and Therapeutic Applications

“…Due to the reduced photon scattering and minimal tissue absorption, fluorescence imaging in the NIR window (700–1700 nm) offers increased tissue penetration depths and a better signal‐to‐noise ratio rendering it ideal for biomedical applications. [ 1–7 ] Currently, NIR fluorescent materials mainly comprise quantum dots, [ 8–10 ] lanthanide‐doped upconverting nanoparticles, [ 11–13 ] organic small molecules, [ 14,15 ] and polymer‐based systems. [ 16 ] However, long‐term toxicity and immunogenicity, non‐biodegradability, as well as photo‐instability of these non‐life‐like materials have restricted their translation into clinical applications.…”