Selective lignin arylation for biomass fractionation and benign bisphenols.

Lignocellulose is mainly composed of hydrophobic lignin and hydrophilic polysaccharide polymers, contributing to an indispensable carbon resource for green biorefineries1,2. When chemically treated, lignin is compromised owing to detrimental intra- and intermolecular crosslinking that hampers downstream process3,4. The current valorization paradigms aim to avoid the formation of new C-C bonds, referred to as condensation, by blocking or stabilizing the vulnerable moieties of lignin5-7. Although there have been efforts to enhance biomass utilization through the incorporation of phenolic additives8,9, exploiting lignin's proclivity towards condensation remains unproven for valorizing both lignin and carbohydrates to high-value products. Here we leverage the proclivity by directing the C-C bond formation in a catalytic arylation pathway using lignin-derived phenols with high nucleophilicity. The selectively condensed lignin, isolated in near-quantitative yields while preserving its prominent cleavable ß-ether units, can be unlocked in a tandem catalytic process involving aryl migration and transfer hydrogenation. Lignin in wood is thereby converted to benign bisphenols (34-48 wt%) that represent performance-advantaged replacements for their fossil-based counterparts. Delignified pulp from cellulose and xylose from xylan are co-produced for textile fibres and renewable chemicals. This condensation-driven strategy represents a key advancement complementary to other promising monophenol-oriented approaches targeting valuable platform chemicals and materials, thereby contributing to holistic biomass valorization.

A novel fluorescence method for the rapid and effective detection of Listeria monocytogenes using aptamer-conjugated magnetic nanoparticles and aggregation-induced emission dots.

Fluorescence-based assays are efficient tools for the detection of Listeria monocytogenes (L. monocytogenes). However, they are always restricted by the phenomenon of aggregation-caused quenching (ACQ). The emergence of aggregation-induced emission (AIE) materials perfectly overcomes this shortcoming. Through harnessing the AIE characteristic with magnetic enrichment, we propose an approach to achieve a promising detection method that combines an aptamer and antibody-based dual recognition units. Aptamer-coupled magnetic beads were used for the specific capture of L. monocytogenes. IgG-TPE-OH@BSA NPs were facilely synthesized through encapsulating 1-(4-hydroxyphenyl)-1,2,2-triphenylethene (TPE-OH) in bovine serum albumin (BSA) microspheres, and possessed a bright fluorescence signal due to the aggregation of TPE-OH in BSA NPs. Rabbit immunoglobulin G (IgG) antibodies were labelled on the surface. In the detection system, the fluorescence intensity of the IgG-TPE-OH@BSA NPs in the supernatant was monitored to avoid the signal interference resulting from the deposit after magnetic separation. Using our strategy, the range of detection for L. monocytogenes is 10-106 cfu mL-1, and the detection limit is as low as 10 cfu mL-1 with a good selectivity. Upon analysis of spiked samples, the recoveries ranged from 95.37% to 101.90% without any pre-enrichment.

Rapid and selective recognition of Vibrio parahaemolyticus assisted by perfluorinated alkoxysilane modified molecularly imprinted polymer film.

Molecular imprinting technology offers a means of tailor-made materials with high affinity and selectivity for certain analysts. However, the recognition and separation of specific bacteria in complex matrices are still challenging. Herein, a bacteria-imprinted polydimethylsiloxane (PDMS) film was facilely prepared and modified with 1H,1H,2H,2H-perfluorooctyltriethoxysilane (POTS). Employing Vibrio parahaemolyticus as a model bacterium, the imprinted surface exhibited three-dimensionality cavities with mean size of 1000 × 800 nm in square and 100 nm in depth. After incubation for 2 h with 6 × 107 CFU mL-1 of V. parahaemolyticus, the imprinted polymer film can reach a 62.9% capture efficiency. Furthermore, the imprinted POTS-modified PDMS film based solid phase extraction combined with polymerase chain reaction and agarose gel electrophoresis allows for detecting 104 CFU mL-1 with excellent selectivity in fresh oyster samples. As a result, the developed selective sample pretreatment method using molecular imprinting technology provides a promising platform for separation, identification, and analysis of pathogens.

Demulsification-induced fast solidification: a novel strategy for the preparation of polymer films.

We demonstrate a novel, simple and convenient demulsification-based method called demulsification-induced fast solidification (DIFS) to fabricate polymer films. Two dimensional films, three dimensional films, and free-standing polyvinyl acetate and polyurethane acrylate films were fabricated via electrochemical deposition using the DIFS method.

A novel electropolymerized fluorescent film probe for TNT based on electro-active conjugated copolymer.

A novel electro-active conjugated copolymer (PFPCz) has been designed, synthesized and used as the precursor of electropolymerization (EP) directly. By optimizing the EP condition, the PFPCz EP films have been prepared and displayed high fluorescent sensitivity to TNT, whose fluorescent intensity could be quenched 68.6% exposed to TNT (50 µM) in aqueous medium. These results suggest PFPCz EP film a promising candidate for TNT detection. Furthermore, this work provides not only a new precursor to EP but also a promising fluorescence film sensor candidate.

Fluorescence detection of trace TNT by novel cross-linking electropolymerized films both in vapor and aqueous medium.

Electropolymerized (EP) films with high fluorescent efficiency are introduced to the detection of trace 2,4,6-trinitrotoluene (TNT). Three electroactive materials TCPC, OCPC and OCz have been synthesized and their EP films have been demonstrated to be sensitive to TNT. Among them, the TCPC EP films have displayed the highest sensitivity to TNT in both vapor and aqueous medium, even in the natural water. It is proposed that the good performances would be caused by the following two factors: first, the cross-linking network of EP films can generate the cavities which benefit the TNT penetration, and remarkably increase the contact area between the EP films and TNT; second, the frontier orbits distribution leads the fast photo-induced electron transfer (PET) from the TCPC EP films to TNT. Our results prove that these EP films are promising TNT sensing candidates and provide a new method to prepare fluorescent porous films.

Detection of TNT explosives with a new fluorescent conjugated polycarbazole polymer.

A novel fluorescent poly(2,7-carbazole) with a 4-[tris-(4-octyloxyphenyl)methyl]phenyl side chain is used to detect the explosive compounds TNT and DNT. It shows high recycled fluorescence quenching sensitivity, which is due to its strong electron donating ability and weaker interaction between the polymer chains caused by the bulky side chain.