Construction of a highly sensitive detection platform for heparin based on a "turn-off" cationic fluorescent dye

A highly sensitive detection platform for heparin was constructed via the utilization of a commercially available cationic fluorescent dye (cresyl violet acetate, CV) as a fluorescence probe. The electrostatic binding between CV and heparin quenched the fluorescence in 4-(2-hydroxyethyl)-1-piperazineethanesulfonic (HEPES) buffer solution (10 mM, pH 7.1). CV was highly selective towards heparin over other potential inferring substances. The detection limit of heparin detection was 5.19 ng/mL, and the linear working range was 0 ∼ 1 μg/mL in HEPES solution. In 1 % serum, the detection platform based on the fluorescence "turn-off" behavior of CV was also successfully constructed with a detection limit of 5.86 ng/mL in the linear range of 0 ∼ 0.8 μg/mL. Moreover, the CV-heparin complex was considered a potential sensor platform for the detection of protamine because of its stronger affinity for heparin and protamine.

Water compatible supramolecular polymers: recent progress

Water compatible supramolecular polymers (WCSPs) combine aqueous compatibility with the reversibility and environmental responsiveness of supramolecular polymers. WCSPs have seen application across a number of fields, including stimuli-responsive materials, healable materials, and drug delivery, and are attracting increasing attention from the design, synthesis, and materials perspectives. In this review, we summarize the chemistry of WCSPs from 2016 to mid-2021. For the sake of discussion, we divide WCSPs into five categories based on the core supramolecular approaches at play, namely hydrogen-bonding arrays, electrostatic interactions, large π-conjugated subunits, host-guest interactions, and peptide-based systems, respectively. We discuss both synthesis and polymer structure, as well as the underlying design expectations. The goal of this overview is to deepen our understanding of the strategies that have been exploited to prepare WCSPs, as well as their properties and uses. Thus, a section devoted to potential applications is included in this review.

Ultrafine fluorene-pyridine oligoelectrolyte nanoparticles for supersensitive fluorescence sensing of heparin and protamine

A new fluorene-pyridine oligoelectrolyte (OFP) is rationally proposed and readily synthesized via a simple one-pot Sonogashira approach. Hence, an unexpectedly small cationic oligomer nanosensor (i.e. OFPNPs, ∼ 1.2 nm in diameter) was conveniently fabricated owing to the enhanced flexibility endowed by the meta-substituted pyridyl unit. Inspiringly, this facile nanoplatform with low cytotoxicity favors the ultrasensitive fluorescence assay for heparin and protamine with a detection limit (LOD, S/N = 3) as low as 1.2 ng mL^-1 and 0.5 ng mL^-1, respectively, involving heparin-induced aggregation of OFPNPs through electrostatic interaction or competitive rebinding of protamine to heparin.

A cysteine-selective fluorescent probe for monitoring stress response cysteine fluctuations

Rare studies provided evidence for the real-time monitoring of stress response cysteine fluctuations. Here, we have successfully designed and synthesized a cysteine-selective fluorescent probe 1 to monitor stress response Cys fluctuations, providing visual evidence of Hg2+ regulated cysteine fluctuations for the first time, which may open a new way to help researchers to reveal the mechanism of heavy metal ion poisoning.