Facile preparation of biocompatible sulfhydryl cotton fiber-based sorbents by "thiol-ene" click chemistry for biological analysis

Nylon 6-cellulose composite hosted in a hypodermic needle: Biofluid extraction and analysis by ambient mass spectrometry in a single device

This study proposes a hypodermic needle (HN) as a sorbent holder and an electrospray (ESI) emitter, thus combining extraction and analysis in a single device. A novel nylon 6-cellulose (N6-Cel) composite sorbent is proposed to extract methadone from oral fluid samples. The cellulosic substrate provides the composite with high porosity, permitting the flow-through of the sample, while the polyamide contributes to the extraction of the analyte. The low price of the devices (considering the holder and the sorbent) contributes to the affordability of the method, and their small size allows easy transportation, opening the door to on-site extractions. Under the optimum conditions, the analyte can be determined by high-resolution ambient ionization mass spectrometry at a limit of detection (LOD) as low as 0.3 μg/L and precision (expressed as relative standard deviation, RSD) better than 9.3%. The trueness, expressed as relative recovery (RR), ranged from 90% to 109%. As high-resolution mass spectrometers are not available in many laboratories, the method was also adapted to low-resolution spectrometers. In this sense, the direct infusion of the eluates in a triple quadrupole-mass spectrometry provided an LOD of 2.2 μg/L. The RSD was better than 5.3%, and the RR ranged from 96% to 121%.

Boron-Modified Defect-Rich Molybdenum Disulfide Nanosheets: Reducing Nonspecific Adsorption and Promoting a High Capacity for Isolation of Immunoglobulin G

A new type of boric acid derivative-modified molybdenum disulfide nanosheet was prepared by amination and sulfur chemical grafting, where lipoic acid, lysine, and 5-carboxybenzoboroxole were used as reactants. The two-dimensional composite, abbreviated as MoS₂-Lys-CBX, is an ultrathin nanosheet with a minimum unit of single or few layers. Compared with the original molybdenum disulfide, the nonspecific adhesion of interfering proteins on the surface was reduced, and the adsorption capacity of glycoproteins was enhanced, which was 1682.2 mg g^-1 represented by IgG. The adsorbed IgG can be easily eluted with 0.3 wt % CTAB with an elution efficiency of 94.1%. Circular dichroism spectra indicate no obvious conformation change of IgG during the purification process by the MoS₂-Lys-CBX nanosheets. The as-prepared MoS₂-Lys-CBX nanosheets were then employed for the isolation of IgG from human serum sample, obtaining high-purity light and heavy chains of IgG, as demonstrated by SDS-PAGE assays.

Window screen inspired fibrous materials with anisotropic thickness gradients for improving light transmittance

Fibrous materials with high light transmittance exhibit great potential in a wide range of applications; unfortunately, fabrication of such materials still remains a challenge due to the strong light scattering caused by the rough fibrous structure and the voids between fibers. Window screens are commonly used in our daily life, and their unique woven structure ensures excellent mechanical properties, while the voids between wires allow light to pass through. By learning from the architecture of window screens, we proposed a novel patterned electrospinning approach with window screen like wire meshes as collectors to deposit fibers with anisotropic thickness gradients and further to improve the optical properties. The results indicated that the obtained fibrous mats closely copied the structure of the wire meshes, and exhibited unique thickness anisotropy with most of the fibers densely packed on the wires in a small area, while very few fibers sparsely suspended in the voids over a large area. Owing to the large area of the thin region within fibrous mats, the overall light transmittance of such a well-organized mat was greatly improved as compared with that of an isotropous mat. Furthermore, by carefully investigating the microstructure of the fibrous mats and simulating the electric field distribution with the software Comsol Multiphysics, a novel needle array collector with an ultra large area of voids was designed to achieve optimal light transparency. Finally, as proof of concepts, we investigated the potential use of transparent fibrous mats as a visual wound dressing and a window dust filter, respectively.

A boronate-decorated porous carbon material derived from a zinc-based metal–organic framework for enrichment of cis-diol-containing nucleosides

A new boronate-decorated carbon material derived from Zn-MOF was synthesized and used to selectively enrich cis-diol nucleosides.

Exploring the effect of vibronic contributions on light harvesting efficiency of NKX-2587 derivatives through vibrationally resolved electronic spectra

The vibrationally resolved electronic spectra of five metal-free NKX-2587 derivatives containing heteroatom with different atomic sizes and electronegativity, were simulated within the Franck-Condon approximation including the Herzberg-Teller and Duschinsky effects, aimed at exploring the correlation of vibronic structure associated with the spectrum and efficiency of dye sensitized solar cells (DSSCs). The parameters of short-circuit current density (J_sc) and open circuit voltage (V_oc) involving efficiency of DSSCs, such as total dipole moments (μ_normal), the light harvesting efficiency (LHE), injection driving force (∆G_inject), and the number of electrons in the conduction band (n_c), were calculated and discussed in detail. Results showed that the heteroatoms in the same period with large size and weak electronegativity and the ones in the same main group with large size and weak electronegativity are beneficial to V_oc. The sizes and electronegativity of the heteroatoms have a weak effect on J_sc. The low-frequency modes play important roles in enhancing the intensities of the electronic spectra and structures can affect light harvesting efficiency (LHE). In this sense, our results provided guidance for understanding the sources of spectral intensities of dye molecules, and a valuable help for rational design of new molecules to improve the energy conversion efficiency (η) of DSSCs.

Preparation of a reactive flame retardant and its finishing on cotton fabrics based on click chemistry

The non-halogenated organophosphorus flame retardant dimethyl-[1,3,5-(3,5-triacryloylhexahydro)triazinyl]-3-oxopropylphosphonate (DHTP) was synthesized and immobilized on cotton fabrics for a flame retardant finishing using click chemistry.

Synthesis of Polyethylenimine Functionalized Mesoporous Silica for In-Pipet-Tip Phosphopeptide Enrichment

Synthesis of functionalized mesoporous silica material with large particle size remains a chanllenge. In this work, polyethylenimine (PEI) functionalized mesoporous silica (PFMS) with particle size as large as 100 μm was successfully synthesized by a facile method. In the synthesis process, PEI served as four roles simultaneously, including functionalized reagent, alkaline catalyst, template for particle formation, and pore-structure-directing agent. The surface areas of the products were higher than 260 m²/g. Benefiting from the large particle size and high surface area, PFMS was packed in a pipet tip to fabricate a convenient and miniaturized solid phase extraction apparatus for sample preparation. Additionally, based on the extremely abundant basic sites in the organic units of PFMS, the in-pipet-tip system was used as an anion-exchanger for phosphopeptide enrichment. The specificity of the developed method was investigated by capture of phosphopeptides from tryptic digests of standard protein mixtures, tryptic digests of nonfat milk, and human serum. Furthermore, the method was utilized to analyze phosphopeptides in tryptic digests of rat brain lysate, and 2251 unique phosphopeptides were successfully detected.

Synthesis and Characterization of Hydrazide-Linked and Amide-Linked Organic Polymers

Four kinds of either hydrazide-linked or amide-linked polymers were facilely synthesized by using hydrazine, tetrakis(4-aminophenyl)methane (TAPM), terephthaloyl chloride (TPC), and trimesoyl chloride (TMC) as building blocks. The morphology, porosity, composition, and surface property of polymers were characterized by scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption measurement, ¹³C/CP-MAS NMR, X-ray photoelectron spectroscopy, etc. The results indicated that building blocks had important effects on morphology and porosity. Poly(TMC-TAPM) synthesized with TMC and TAPM showed the highest surface area of 241.9 m² g^-1. In addition, note that a hollow structure with ∼20 nm wall thickness was formed in poly(TMC-hydrazine) prepared with TMC and hydrazine. Further study indicated that both carboxyl groups (-COOH) and hydrazide groups (-CONH-NH₂) existed on the surface of poly(TMC-hydrazine), besides the mainly hydrazide linkage (-CONH-NHOC-). Taking advantages of good hydrophilicity and special functional groups on the surface, we finally adopted poly(TMC-hydrazine) to enrich glycopeptides from tryptic digest via both hydrophilic interaction chromatography method with identification of 369 unique N-glycosylation sites and hydrazide chemistry method with identification of 88 unique N-glycosylation sites, respectively.

Simultaneous determination of polycyclic aromatic hydrocarbons and tobacco-specific N-nitrosamines in mainstream cigarette smoke using in-pipette-tip solid-phase extraction and on-line gel permeation chromatography-gas chromatography-tandem mass spectrometry

In this study, a silica/primary secondary amine (SiO2/PSA) was used as an in-pipette-tip solid phase extraction (SPE) sorbent for the simultaneous determination of polycyclic aromatic hydrocarbons (PAHs) and tobacco-specific N-nitrosamines (TSNAs) in mainstream cigarette smoke (MSS). We investigated several parameters including an extraction procedure of total particulate matter, type and amount of sorbent and on-line gel permeation chromatography parameters to obtain optimum conditions for a new strategy to target analytes. Under the optimized conditions, we developed a method for the simultaneous determination of PAHs and TSNAs in MSS by coupling in-pipette-tip SPE procedures to an on-line gel permeation chromatography-gas chromatography-tandem mass spectrometry (on-line GPC-GC-MS(2)). Our method had limits of detection for target analytes ranging from 0.01 to 0.23ng/cig. Good linearities were obtained with coefficients of determination (R(2)) greater than 0.9984 for all target analytes. Good reproducibility was obtained as intra- and inter-day precisions, and the relative standard deviations were less than 11.4 and 13.3%, respectively. The recoveries were in the range of 77.1-108.6% at different concentrations for real samples. Compared to previous standard methods for the determination of PAHs and TSNAs in MSS, our method was highly effective, fast, and had low consumption of organic solvent and a high degree of automation. Finally, our method successfully analyzed PAHs and TSNAs in real samples, and no significant deviations were observed when compared to similar analysis using standard methods.

Enhanced binding capacity of boronate affinity fibrous material for effective enrichment of nucleosides in urine samples

A novel polyethyleneimine-modified boronate affinity fibrous cotton with high binding capacity was prepared for in-pipette-tip solid phase extraction nucleosides in human urine.