Integration of Fe3O4@UiO-66-NH2@MON core-shell structured adsorbents for specific preconcentration and sensitive determination of aflatoxins against complex sample matrix

Aflatoxins have been a hot topic in the field related into public health and ecosystem protection, and great effort has been made in developing of adsorptive materials for effective probing the target aflatoxins. Conventional materials, like metal-organic frameworks (MOFs) showed promising application in separation science. However, the cumbersome separation process, competitive adsorption are also major challenges. Regarding this, a novel magnetic micro-composite denoted as Fe₃O₄@UiO-66-NH₂@MON with core-shell structure was constructed. The core of Fe₃O₄ microspheres was coated with MOFs crystals, and then microporous organic network (MON) was introduced onto the surface of Fe₃O₄@UiO-66-NH₂ through a sonogashira coupling reaction. It exhibited good magnetic separation ability, which effectively simplified the pre-treatment steps. The proposed method possessed excellent selectivity and sensitivity, with detection limits in the range of 0.15-0.87 μg L^-1 combination with HPLC analysis. More importantly, the MON coating significantly improved the hydro-stability of whole adsorbents, thus enhancing the adsorption efficiency and favoring the practical application of the materials. The developed Fe₃O₄@UiO-66-NH₂@MON-based solid extraction method has been well-applied for real sample analysis, with the recovery of 87.3%-101.8%. We believe the newly-constructed hybrid nano-adsorbents hold great potential in further application in various analytical methods for different target analytes.

Preparation of macroscopic carbon nanohorn-based monoliths in polypropylene tips by medium internal phase emulsion for the determination of parabens in urine samples

A porous monolithic solid based on single-walled carbon nanohorns dahlia-like structure, produced from a medium internal phase emulsion (MIPE), was prepared in a polypropylene tip using UV energy. Thus, single-walled carbon nanohorns (SWNHs) were added to the organic phase where they polymerized in the presence of a radical initiator. A cross-linker (ethylene dimethacrylate, EDMA) was also used in order to obtain a more robust structure. On the other hand, aqueous phase was the responsible for generating the pores in the final solid being inside the droplets generated by the surfactant (Pluronic L121) used to stabilize the polymerization emulsion. Variables related to the formation of the monolithic phase including the stability and composition of emulsion mixture, size of pores, solvent flow resistance and robustness, were studied in detail. In addition, the potential of the SWNH-monolith as extractant phase was evaluated using parabens as target analytes. The LODs ranged from 1 to 7 μg L^-1, while the linear range was extended up to 5000 μg L^-1. The reproducibility of the extraction procedure with different batches of emulsions was acceptable with RSD values < 16% and one prepared SWNH-tip can be used for more than 100 times without apparent extraction losses. The microextraction unit yielded an enrichment factor of 20 for all analytes (extraction efficiency of 100%), with recovery values between 80% and 116% in human urine samples.

Enhancing the solubility and bioactivity of anticancer drug tamoxifen by water-soluble pillar[6]arene-based host-guest complexation

A water-soluble pillar[6]arene functions as a solubilizing agent to enhance the solubility and bioactivity of poorly water-soluble anticancer drug tamoxifen by host-guest complexation between it and tamoxifen.

Biological and related applications of pillar[n]arenes

Pillar[n]arenes are a new class of synthetic supramolecular macrocycles streamlined by their particular pillar-shaped architecture which consists of an electron-rich cavity and two fine-tuneable rims. The ease and diversity of the functionalization of the two rims open possibilities for the design of new architectures, topological isomers, and scaffolds. Significantly, this emerging class of macrocyclic receptors offers a unique platform for biological purposes. This review article covers the most recent contributions from the pillar[n]arene field in terms of artificial membrane transport systems, controlled drug delivery systems, biomedical imaging, biosensors, cell adhesion, fluorescent sensing, and pesticide detection based on host-guest interactions. The review also uniquely describes the properties of sub-units that make pillar[n]arenes suitable for biological applications and it provides a detailed outline for the design of new innovative pillar-like structures with specific properties to open up a new avenue for pillar[n]arene chemistry.

3D-Printed Microflow Injection Analysis Platform for Online Magnetic Nanoparticle Sorptive Extraction of Antimicrobials in Biological Specimens as a Front End to Liquid Chromatographic Assays

In this work, the concept of 3D-printed microflow injection (3D-μFI) embodying a dedicated multifunctional 3D-printed stator onto a rotary microvalve along with a mesofluidic sample preparation platform is proposed for the first time. A transparent 3D-printed stereolithographic mesofluidic chip device accommodating polyaniline (PANI) decorated magnetic nanoparticles (32.5 ± 3.8 mg) is harnessed to in-line sorptive microextraction as a front end to liquid chromatography with peak focusing. As a proof-of-concept application, the 3D-μFI assembly was resorted to matrix cleanup and automatic programmable-flow determination of organic emerging contaminants (4-hydroxybenzoate analogues and triclosan as antimicrobial model analytes) in human saliva and urine samples. By using a sample volume of 1.0 mL with a loading flow rate of 200 μL min^-1, an eluent volume of 120 μL at 80 μL min^-1, and online HPLC injection of 300 μL of the mixture of eluate and Milli-Q water (in a 1:2 ratio) to prevent band broadening effects of the most polar analytes, the limits of detection (3σ criterion) ranged from 1.1 to 4.5 ng mL^-1 for methylparaben (MP), ethylparaben (EP), propylparaben (PrP), phenylparaben (PhP), butylparaben (BP), and triclosan (TCS). Enhancement factors of 16-25 were obtained for the target analytes. Spike recoveries ranged from 84 to 117% for both saliva and urine samples. The online 3D-μFI hyphenated method is synchronized with the chromatographic separation and features a chip lifetime of more than 20 injections with minimal losses of moderately nonpolar compounds on the walls of the mesofluidic device.

Nanoparticles functionalized with supramolecular host-guest systems for nanomedicine and healthcare

Synthetic macrocyclic host compounds can interact with suitable guest molecules via noncovalent interactions to form functional supramolecular systems. With the synergistic integration of the response of molecules and the unique properties at the nanoscale, nanoparticles functionalized with the host-guest supramolecular systems have shown great potentials for a broad range of applications in the fields of nanoscience and nanotechnology. In this review article, we focus on the applications of the nanoparticles functionalized with supramolecular host-guest systems in nanomedicine and healthcare, including therapeutic delivery, imaging, sensing and removal of harmful substances. A large number of examples are included to elucidate the working mechanisms, advantages, limitations and future developments of the nanoparticle-supramolecule systems in these applications.

Preconcentration of bisphenols by using calix[4]arene derivatives modified porous polymer monolith coupled with HPLC

A functionalized calix[4]arene (alkenyl@C[4]A) was introduced into the poly(butyl methacrylate-ethylene dimethacrylate) monolith inside a capillary to prepare a polymer monolith microextraction (PMME) material (poly(BMA-alkenyl@C[4]A-EDMA)).

Pillar[5,6]arene-functionalized silicon dioxide: synthesis, characterization, and adsorption of herbicide

A layer of synthetic supramolecular macrocycles, that is, perhydroxyl-pillar[5]arene and perhydroxyl-pillar[6]arene, has been covalently attached to hydrophilic silica supports through Si-O-Si linkages with a coverage of up to 250 μmol pillar[5,6]arenes/g to form novel absorbent hybrid materials. Their adsorption toward a typical herbicide, namely, paraquat, from its aqueous solution has been investigated. Kinetic studies disclosed that paraquat adsorption fits a first-order kinetic model. Equilibrium adsorption data could be explained very well by the Langmuir equation. The pillar[6]arene-modified materials showed more obvious adsorption as compared with pillar[5]arene-modified ones and the saturation adsorption quantity reached about 0.20 mmol of paraquat per gram of materials. The entire process of adsorption was endothermic, and significantly an elevated temperature led to an increase in the adsorption quantity. This new type of pillarene-based adsorbent materials can be considered as a potential adsorbent for harmful substances removal from wastewaters.

Supramolecular assembly-induced yellow emission of 9,10-distyrylanthracene bridged bis(pillar[5]arene)s

Newly synthesized DSA-bridged bis(pillar[5]arene)s with AIE properties form linear supramolecular polymers upon binding to a neutral guest linker, exhibiting supramolecular assembly-induced yellow fluorescence emission.