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.…”

Development of Polymethine Dyes for NIR‐II Fluorescence Imaging and Therapy

“…However, the albumin encapsulation strategy introduces relatively larger sizes, forfeiting the advantage of rapid clearance seen with unbound polymethine cyanine dyes, and potentially contributing to increased background signals. [123,14] Zhu and co-workers ingeniously developed the polymethine cyanine-protein composite strategy by covalently linking chlorine dyes with 𝛽-lactoglobulin (𝛽-LG), yielding bright and stable NIR-I/II fluorophores such as 𝛽-LG@IR-780 (Figure 7). 𝛽-LG acts as a protective casing since it has a low mass (18.4 kDa) and very small size (<5 nm), giving 𝛽-LG@IR-780 excellent properties in terms of biocompatibility and renal excretion.…”