In-situ gastritis diagnosis by an oral-administration NIR fluorescent probe with a large Stokes shift and high signal-to-noise ratio.

[Display omitted] • The first oral-administration near-infrared fluorescence molecular (NS-V) for detection the variation of viscosity was established. • The probe NS-V was developed on the basis of naphthalene and pyridine benzyl chloride salt, and emitted at NIR region (710 nm). • The robust probe NS-V possesses a large Stokes shift (∼262 nm in MeCN) and high signal-to-noise ratio. • The new probe NS-V can elucidate the variations of mitochondrial viscosity in abnormal state cells. • The robust probe NS-V was realized in situ visualization the changes of viscosity in gastritis mice, for the first time. Gastritis is one of the most common digestive disorders and affecting millions of people worldwide. Recent investigations discovered that abnormal viscosity changes in organisms are associated with an increasing number of diseases that cannot be cured or managed. However, the relationship between gastritis and viscosity has not been explored so far due to lacking the suitable tools for in situ detecting the variations of viscosity in stomach. Herein, we developed a new oral-administration fluorescent probe (NS-V) for in situ elucidation of gastritis viscosity variations, for the first time. Based on the TICT mechanism, the probe employs naphthalene as the fluorescence platform, the rotatable single bond as the viscosity sensitive site, N, N -dimethyl as the strong electron donating moiety and the pyridine salt as the strong withdrawing group to enlarge the π-conjugated system to prolong the emission wavelength. Interestingly, NS-V revealed a good fluorescence response for viscosity at the NIR region from a silent "off" state to "on" and demonstrated high sensitivity, large Stokes shift (262 nm in MeCN), and high signal-to-noise ratio. In addition, NS-V could elucidate the altered mitochondrial viscosity in inflammatory cells. More importantly, utilizing these satisfactory features of NS-V , we discovered a significant increase in viscosity in the gastritis mice. Notably, with the assistance of the oral fluorescence molecule, in vivo and in situ visualizing for the first time revealed the positive correlation between viscosity and gastritis. This work provides an important basis for the diagnosis of gastritis and the robust probe developed in this work possesses a potential application in diagnosis of gastritis without any pain. [ABSTRACT FROM AUTHOR]