Two near-infrared highly sensitive cyanine fluorescent probes for pH monitoring

Two near-infrared（NIR） p H-activated heptamethine indocyanine probes with quaternary ammonium unit were designed and synthesized. The absorption and emission titrations indicate that cationic structure improves the cyanine dye＇s aqueous solubility and these two probes exhibit highly sensitive response to p H in acid condition. Their fluorescence intensities both gradually increase about 25-fold from p H 7.60 to 3.00 with p Ka values of 4.72 and 4.45 respectively, which are suitable for studying acidic organelles in living cells. Moreover, their fluorescence intensities are linearly proportional to p H values in the range of 5.50–4.00. These results are probably attributed to the protonation of the indole nitrogen atoms, which are verified by 1H NMR spectra. Furthermore, these two probes can achieve real-time imaging of cellular p H and detection of p H in situ in living He La cells due to their excellent properties,including good reversibility, desirable photostability, high selectivity, low cytotoxicity and remarkable membrane permeability.

Thermally drawn multifunctional fibers: Toward the next generation of information technology

As the fundamental building block of optical fiber communication technology,thermally drawn optical fibers have fueled the development and prosperity of modern information society.However,the conventional step-index configured silica optical fibers have scarcely altered since their invention.In recent years,thermally drawn multifunctional fibers have emerged as a new yet promising route to enable unprecedented development in information technology.By adopting the well-developed preform-to-fiber manufacturing technique,a broad range of functional materials can be seamlessly integrated into a single fiber on a kilometer length scale to deliver sophisticated functions.Functions such as photodetection,imaging,acoustoelectric detection,chemical sensing,tactile sensing,biological probing,energy harvesting and storage,data storage,program operation,and information processing on fiber devices.In addition to the original light-guiding function,these flexible fibers can be woven into fab-rics to achieve large-scale personal health monitoring and interpersonal com-munication.Thermally drawn multifunctional fibers have opened up a new stage for the next generation of information technology.This review article summarizes an overview of the basic concepts,fabrication processes,and developments of multifunctional fibers.It also highlights the significant pro-gress and future development in information applications.