NIR‐II cyanine@albumin fluorophore for deep tissue imaging and imaging‐guided surgery

Abstract

The near‐infrared (NIR)‐II bioimaging technique is highly important for both diagnosing and treating life‐threatening diseases due to its exceptional imaging capabilities. However, the lack of suitable NIR‐II fluorescent probes has hindered their widespread clinical application. To address this issue, the binding of albumin to cyanine dyes has emerged as a practical and efficient method for developing high‐performance NIR‐II probes. Cyanine dyes can bind with exogenous and endogenous albumin through either covalent or noncovalent interactions, serving various purposes. The resulting cyanine@albumin (or albumin@cyanine) fluorophores offer significant advantages, including strong brightness, excellent photostability, good biosafety, and a long‐term, high‐resolution imaging window. Cyanine dye in situ binding with endogenous albumin can also enhance the targeting imaging capability. This review provides a summary of the interaction mechanism, performance enhancement, tumor‐targeting feature, and in vivo imaging applications of the cyanine@albumin fluorophores. These advancements not only highlight the unique characteristics of cyanine@albumin fluorophores in preclinical research but also emphasize their potential for clinical diagnosis.

A planar electronic acceptor motif contributing to NIR-II AIEgen with combined imaging and therapeutic applications

“…S8 † ). 21 Note that the strong electronic acceptor has contributed greatly to the NIR-I absorption and NIR-II emission, while such a property is particularly useful to improve the imaging depth and resolution by reducing light scattering and absorption from biological tissue and biological self-fluorescence interference. Moreover, the Stokes shift of Py-NIR NPs is recorded as ∼430 nm, which is much larger than that of BBTD-TPA (350 nm).…”

Recent Advances in NIR-II Materials for Biomedical Applications

“…In addition to the superior photophysical properties, some NIR-I dyes also exhibit strong binding ability with proteins, which confers the dyes with not only enhanced brightness, but also prolonged blood circulation time and adjustable pharmacokinetics. 49 As one of the most abundant plasma proteins in mammal blood circulation, albumin has been used as theranostic drug carrier and for nanoparticle stabilization in the past two decades. 50 Combined with this property, we developed a series of dye-protein complexes.…”

NIR-II Fluorescent Probes for Fluorescence-Imaging-Guided Tumor Surgery

“…Notably, cyanine dyes like 1-Cl−5-Cl exhibit localization in various solid tumors such as lung cancer, prostate cancer, gastric cancer, and kidney while avoiding healthy tissue. The accumulation characteristics of these cyanine dyes with meso-Cl are predominantly attributed to their covalent linkage to albumin in vivo [21]. Moreover, it is hypothesized that the complex could be effectively internalized by tumor cells due to the overexpression of albumin receptors in tumor cells.…”

“…, provided an overview of NIR-II fluorescence agents and their diverse applications in guiding tumor surgeries [20]. Zhu et al, 2023, offered an overview of the mechanism of interaction, improved performance, capability of tumor targeting, and in vivo fluorescence imaging of the NIR-II fluorophores [21]. Wang et al, 2023, summarized the versatile designs and functionality and applications of NIR-II fluorescent probes for in vivo processes in multichannel biosensing, biological process monitoring, cellular tracking, and pathological analysis [22].…”