Advanced Fluorescence Imaging Technology in the Near-Infrared-II Window for Biomedical Applications

Abstract

Fluorescence imaging has become a fundamental tool for biomedical applications; nevertheless, its intravital imaging capacity in the conventional wavelength range (400−950 nm) has been restricted by its extremely limited tissue penetration. To tackle this challenge, a novel imaging approach using the fluorescence in the second near-infrared window (NIR-II, 1000−1700 nm) has been developed in the past decade to achieve deep penetration and high-fidelity imaging, and thus significant biomedical applications have begun to emerge. In this Perspective, we first examine recent discoveries and challenges in the development of novel NIR-II fluorophores and compatible imaging apparatuses. Subsequently, the recent advances in bioimaging, biosensing, and therapy using such a cutting-edge imaging technique are highlighted. Finally, based on the achievement in the representative studies, we elucidate the main concerns regarding this imaging technique and give some advice and prospects for the development of NIR-II imaging for future biomedical applications.

Rapid Unperturbed‐Tissue Analysis for Intraoperative Cancer Diagnosis Using an Enzyme‐Activated NIR‐II Nanoprobe

“…Specifically, fluorescence molecular imaging featured with real‐time, high sensitivity, high specificity, as well as absence of ionizing radiation, is considered to be the preferential option for intraoperative histopathology diagnosis [4–8] . Recently, emerging near‐infrared II fluorescence (NIR‐II, 1000–1700 nm) imaging technology exhibits significantly increased tissue penetration, spatial resolution and negligible autofluorescence, enabling higher precision and sensitivity in disease detection [9–28] …”

“…[4][5][6][7][8] Recently, emerging near-infrared II fluorescence (NIR-II, 1000-1700 nm) imaging technology exhibits significantly increased tissue penetration, spatial resolution and negligible autofluorescence, enabling higher precision and sensitivity in disease detection. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] Children neuroblastoma (NB), the most common extracranial solid tumor in childhood, accounting for 8-10 % of all childhood malignancies, is mainly treated on surgery. [29][30][31][32][33] However, it remains challenging to make a quick decision on the malignancy and benignancy of the tissues during surgical operation.…”

Phenanthridine‐Based Donor/Acceptor Fluorescent Dyes: Synthesis, Photophysical Properties and Fluorometric Sensing of Biogenic Primary Amines

“…Though these methods are advantageous, they have some drawbacks such as specialized instrumentation, low sensitivity, low selectivity and short lifetime [33–34] . In recent years, fluorescence‐based detection methods are widely used as the biomedical, environmental monitoring, clinical testing, food safety testing and other fields as it has high sensitivity and selectivity [35–60] …”

<p>Facile Synthesis of Melanin-Dye Nanoagent for NIR-II Fluorescence/Photoacoustic Imaging-Guided Photothermal Therapy</p>

“…A novel fluorescence imaging approach in the second NIR window (NIR-II, 1000-1700 nm) provides deeper tissue penetration (~10 mm), a higher signal-tonoise ratio, and better spatial resolution than NIR-I because of minimal photon scattering and tissue autofluorescence. 2 Recent studies, including those regarding the detection of metastatic lymph nodes, 3 tumor and vessel imaging, [4][5][6] and intraoperative guidance, 7,8 have shown that biological imaging advantages significantly improves as wavelengths increase. Thus far, quantum dots, [9][10][11] carbon nanotubes, 12,13 rare earth-doped nanoparticles, 14,15 squaraine dyes, 16,17 semiconducting polymer nanoparticles, 18 and small-molecule dyes 5,19,20 have all been actively used for NIR-II imaging.…”