Small molecular fluorophores in the second near-infrared window (NIR-II) have aroused much interest because of their excellent performance. Herein, a new small molecular NIR-II fluorophore, FM1210, with maximal emission beyond 1200 nm is reported. Compared to the corresponding control fluorophore CF1065, FM1210 exhibits an increase of 145 nm in the emission maximum, which is ascribed to the simultaneous introduction of both a Se atom and amino groups into the benzo[1,2-c:4,5-c′]bis([1,2,5]thiadiazole) skeleton. This large increase in the maximal emission enables FM1210 to be capable of in vivo imaging with lower autofluorescence, higher signal-to-background ratio, and better resolution. Moreover, nanosized FM1210 encapsulated in liposomes possesses passive targeting ability and good water solubility, and is suitable for imaging a tumor and even its vasculature with high signal-to-background ratio.

The accurate discrimination of microRNAs (miRNAs) with highly similar sequences would greatly facilitate the screening and early diagnosis of diseases. In the present work, a locked nucleic acid (LNA)-modified probe was designed and used for α-hemolysin (α-HL) nanopore to selectively and specifically identify miRNAs. The hybridization of the LNA probe with the target miRNAs generated unique long-lived signals in the nanopore thus facilitated an accurate discrimination of miRNAs with similar sequences, even a single-nucleotide difference. Furthermore, the developed nanopore-based analysis with LNA probe could selectively detect target miRNAs in a natural serum background. This selective and sensitive approach may be highly valuable in the detection of clinically relevant biomarkers in complex samples.

Acetylcholinesterase (AChE) is an extremely critical hydrolase tightly associated with neurological diseases. Currently, specific substrates available for imaging AChE activity still remain a great challenge due to the interference from...