Conjugated Polymer Nanoparticles as a Universal High-Affinity Probe for the Selective Detection of Microplastics.

Microplastic (MP) pollution is a global challenge that requires immediate mitigation practices. Monitoring is crucial for quantifying MPs, but their mitigation remains very challenging due to several factors, including the lack of selective materials to specific polymers, and the low sensitivity of the current detection techniques. In this work, we introduce a novel design for the selective detection of MPs through fluorescence spectroscopy by exploiting conjugated polymer nanoparticles (CPNs). Fluorescent diketopyrrolopyrrole nanoparticles were prepared by nanoprecipitation to incorporate peripheral hyaluronic acid to increase their affinity for various plastics. The affinity of the new ligand for various types of MPs was examined through several characterization techniques, including fluorescence spectroscopy and microscopy, nanoparticle tracking analysis and computational studies. The new CPN were shown to be highly fluorescent in the presence of typically abundant MPs, achieving very strong binding constants in the picomolar range. This very strong affinity for a broad family of plastics was found to be the results of cooperative supramolecular effects and topographical affinity, as probed by advanced microscopy and in silico studies. Furthermore, the new affinity probes were shown to be highly selective for MPs, allowing for their detection in heterogeneous samples, including soil debris and other organic contaminants. The new materials design introduced in this work constitute a promising platform for the development of novel MP detection devices directly useable at the point of collection. Moreover, it opens new avenue for the mitigation of this environmental hazard through tailorable materials.

Impairing proliferation of glioblastoma multiforme with CD44+ selective conjugated polymer nanoparticles.

Glioblastoma is one of the most aggressive types of cancer with success of therapy being hampered by the existence of treatment resistant populations of stem-like Tumour Initiating Cells (TICs) and poor blood-brain barrier drug penetration. Therapies capable of effectively targeting the TIC population are in high demand. Here, we synthesize spherical diketopyrrolopyrrole-based Conjugated Polymer Nanoparticles (CPNs) with an average diameter of 109 nm. CPNs were designed to include fluorescein-conjugated Hyaluronic Acid (HA), a ligand for the CD44 receptor present on one population of TICs. We demonstrate blood-brain barrier permeability of this system and concentration and cell cycle phase-dependent selective uptake of HA-CPNs in CD44 positive GBM-patient derived cultures. Interestingly, we found that uptake alone regulated the levels and signaling activity of the CD44 receptor, decreasing stemness, invasive properties and proliferation of the CD44-TIC populations in vitro and in a patient-derived xenograft zebrafish model. This work proposes a novel, CPN- based, and surface moiety-driven selective way of targeting of TIC populations in brain cancer.

Greenhouse tomato plant roots/carboxymethyl cellulose method for the efficient removal and recovery of inorganic phosphate from agricultural wastewater.

Phosphate (P) is a biologically important compound that is commonly incorporated into fertilizers. Wastewater from agricultural processes results in excessive accumulation of P and eutrophication of lakes. We have developed a system for the remediation, recovery, and potential reuse of P from agricultural wastewater using tomato plant roots (roots) as a capture matrix and carboxymethyl cellulose (CMC) as an eluent and enhancer of P precipitation. Untreated roots can bind up to 55.2 ±â€¯15.2 grams of P per kilogram (g/kg) of roots in comparison to the maximum 8.2 ±â€¯1.5 g/kg bound by the previously used iron-chitosan (Fe-chito). The addition of CMC enhances the precipitation of P with a clearance of 97.2% as opposed to 33.3% without CMC. On site tests show an average removal of 226.5 µg/L per day or a total of ∼28 g of P removed after 23 days. This corresponds to a 71% P removal rate.