ABSTRACT
A novel nanosensor is developed for selective and highly sensitive detection of phytic acid (PA) based on small-sized conjugated polyelectrolyte dots (Pdots) fabricated from a new conjugated polymer (P1) by a modified reprecipitation method. P1 featuring a π-delocalized backbone bearing meta-substituted pyridyl groups can be endowed with enhanced flexibility and hence is beneficial for the synthesis of ultrasmall Pdots (i.e. Pdot-1, â¼3.8â¯nm in average diameter) as well as for the binding of Fe3+, thus leading to the obvious fluorescence quenching of Pdot-1 (â¼444â¯nm) in the presence of Fe3+ via an electron transfer (ET) process. In addition, phytic acid with six phosphate groups exhibits strong chelating ability. When phytic acid is added, phytic acid readily binds to Fe3+ and the fluorescence of Pdot-1 around 444â¯nm can be recovered, rendering the supersensitive and selective sensing of PA. Under the optimum conditions, this ultra-small Pdot-based nanoprobe favors the fluorescent determination of PA with the detection limit as low as 10â¯nM. Particularly, Pdot-1 with bright blue fluorescence exhibits low cytotoxicity. Furthermore, the small-sized and biocompatible Pdot-1 can be applied to the sensitive fluorescence assay for PA in cell extracts and the efficient imaging of PA in live cells.
ABSTRACT
Indocyanine green (ICG) is the only near-infrared (NIR) dye approved by the United States Food and Drug Administration (FDA). Although it is highly desirable, some bottlenecks still remain in clinical applications, such as poor photostability, poor thermal stability, and lack of target specificity. To solve these problems, a zeolitic imidazolate framework-8 (ZIF-8)-based ICG theranostic agent was constructed by one-pot synthesis for fluorescence imaging and photothermal therapy (PTT). The as-synthesized ICG@ZIF-8 nanoparticles (NPs) displayed ultrahigh loading capacity, superior photothermal stability, good anti-photobleaching ability, good biocompatibility, efficient cellular uptake, and favourable photothermal killing capacity for human hepatocarcinoma SMMC-7721 cells. Importantly, in vivo experiments showed that ICG@ZIF-8 NPs accurately and sensitively detected tumors by fluorescence molecular imaging. The PTT results indicated that ICG@ZIF-8 NPs efficiently induced a local ablation effect under a single NIR laser irradiation. The tumor was completely suppressed, and no tumor recurrence or treatment-induced toxicity was observed. The described particles have the potential to act as a promising platform for cancer theranostic nanomedicine.
