Abstract
Recently, second near-infrared (NIR-II) fluorescent imaging has been widely applied in biomedical diagnosis, due to its high spatiotemporal resolution and deep tissue penetration. In contrast to the “always on” NIR-II fluorescent probes, the activatable NIR-II fluorescent probes have specific targeting to biological tissues, showing a higher imaging signal-to-background ratio and a lower detection limit. Therefore, it is of great significance to utilize disease-associated endogenous stimuli (such as pH values, enzyme existence, hypoxia condition and so on) to activate the NIR-II probes and achieve switchable fluorescent signals for specific deep bioimaging. This review introduces recent strategies and mechanisms for activatable NIR-II fluorescent probes and their applications in biosensing and bioimaging. Moreover, the potential challenges and perspectives of activatable NIR-II fluorescent probes are also discussed.
Highlights
New Accurate Diagnosis Strategy for Fluorescence imaging techniques are widely used in the fields of disease detection and diagnosis, surgical navigation, and drug delivery, due to their high sensitivity and noninvasiveness, and the absence of ionizing radiation [1,2,3]
Organic NIR-II fluorescent probes are applied in biological imaging for disease diagnosis, and mainly include BBTD dyes, aggregation-induced emission luminogens (AIEgens), semiconducting polymer nanoparticles (SPNPs), cyanine dyes, rhodamine analogs, and boron dipyrromethenes (BODIPYs), with representative structures CH1055, TQ-BPN, poly, FD-1080, RhIndz, and NJ1060, respectively (Figure 1) [30,31]
The fluorescence imaging of BTC1070 in gastric juices at different pH values was monitored by noninvasive ratiometric imaging at different tissue depths, and the results indicated that BTC1070 could be used for highcontrast fluorescence imaging of deep tissues, to noninvasively detect the pH value in gastric juice (Figure 2d)
Summary
New Accurate Diagnosis Strategy for Fluorescence imaging techniques are widely used in the fields of disease detection and diagnosis, surgical navigation, and drug delivery, due to their high sensitivity and noninvasiveness, and the absence of ionizing radiation [1,2,3]. NIR-II fluorescence probes, realizing the accurate diagnosis of the underlying disease [23]. Biosensors 2021, 11, 436 activate NIR-II fluorescence probes, realizing the accurate diagnosis of the underlying disease [23]. Compared with the “always on” types of NIR-II fluorescent probes, activatable. State intissues the diseased tissues canimprove significantly sensitivity and resolution of the fluorescence imaging [27,28,29]. It is of great improve the sensitivity and resolution of the fluorescence imaging [27,28,29]. It is significance to utilize disease-associated endogenous stimuli to activate NIR-II of great significance to utilize disease-associated endogenous stimuli to actifluorescent for highly sensitive andsensitive high-resolution bioimaging.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
