A New Phenolate‐Ion‐Type Two‐Photon Near Infrared Fluorophore‐Based Biosensor for High‐Performance Detection of HNO

Abstract

Although (E)‐4‐(2‐(4‐(dicyanomethylene)‐4H‐chromen‐2‐yl)vinyl)phenolate anion (DCPO−) has recently emerged as a potential near infrared (NIR) biosensor signaling unit, the pKa value of its conjugate acid is relatively high (∼9); this will lead to relatively low concentrations of DCPO− under physiological conditions and, hence, unsatisfactory sensitivity of DCPO−‐based bio‐probes. By difluoro‐substitution on DCPO−, we have exploited a new fluorophore of o‐FDCPO− whose conjugate acid has a much lower pKa value of 7.42. Meanwhile, o‐FDCPO− is NIR emissive with λem=693 nm and has a 0.76‐fold higher fluorescence efficiency than DCPO−. The significant superiority of o‐FDCPO− over DCPO− in sensitivity for NIR biosensor applications was confirmed by comparative studies on two HNO probes, namely o‐FDCPO‐P and DCPO‐P, which bear signaling units of o‐FDCPO− and DCPO−, respectively. Moreover, o‐FDCPO‐P has been demonstrated to be a high‐performance HNO probe with high selectivity, high sensitivity (detection limit: 50 nm), and a rapid response, together with a two‐photon NIR‐excitation imaging capability.

A NIR-Fluorochrome for Live Cell Dual Emission and Lifetime Tracking from the First Plasma Membrane Interaction to Subcellular and Extracellular Locales

“…If utilized in this format, the data loss imposed by a dark-off state could be circumvented. As such, we were encouraged to explore the prospect of expanding their use from one to two wavelengths using microscopy instrumentation capable of routine imaging in the 700-850 nm range [33,34]. Fluorophores with the potential to elicit two distinct interchangeable and relatable emissions are of elevated value with respect to single signal emissions.…”

“…If utilized in this format, the data loss imposed by a dark-off state could be circumvented. As such, we were encouraged to explore the prospect of expanding their use from one to two wavelengths using microscopy instrumentation capable of routine imaging in the 700–850 nm range [ 33 , 34 ].…”

Tuning the antiaromatic character and charge transport of pentalene-based antiaromatic compounds by substitution

“…The realization of organic molecules having optimally placed selected donor (D)–acceptor (A) moieties/functionalities is a proven design strategy to achieve organic semiconductors for opto-electronics since the electronic structure, optical absorption, energy levels, and solid-state packing can be tuned to the greatest extent. Indeed, numerous high-performance organic semiconductors for OSCs, 45–47 OFETs, 48–50 organic light-emitting diodes (OLEDs), 51 and organic sensors 52,53 have such D–A cores and/or substituent patterns.…”

Near-Infrared Ratiometric Two-Photon Probe for pH Measurement in Human Stomach Cancer Tissue

“…20−25 However, there is a considerable need to develop a NIR emissive and ratiometric TP pH probe to enhance the sensitivity in live tissues. 26 Previously, we developed ratiometric TP probes for studying pH, in which the intramolecular charge transfer (ICT) of the molecular probes controlled the electron donating or accepting ability through protonation and deprotonation. 31−35 Here, we report a TP active rigid hemicyanine core as a ratiometric fluorescent probe (HCC1) that emits double NIR emission bands and whose emission properties vary under distinct pH ranges under physiological conditions.…”

“…In contrast, two-photon (TP) microscopy uses safer two NIR photons in the range of 690–1000 nm, resulting in improved spatial resolution, minimized photodamage, and increased deeper tissue light penetration, which allows better three-dimensional (3D) resolution. , In addition, an NIR emissive (i.e., NIR-to-NIR) TP molecular probe would have enhanced biomedical applications as most reported TP molecular probes emit at a UV–visible range . Recently, TP probes with NIR emission ability have been investigated for fluorescent imaging in biological systems. − However, there is a considerable need to develop a NIR emissive and ratiometric TP pH probe to enhance the sensitivity in live tissues. − …”