An HDBB-based fluorescent probe for the sensitive detection of human serum albumin.

The detection of human serum albumin (HSA) in bodily fluids is of great significance in the biomedical area because HSA in bodily fluids is commonly used as a biomarker for the early diagnosis of diseases. To detect HSA, we employed HDBB, 4,4'-(hydrazine-1,2-diylidene bis(methanylylidene)) bis(3-hydroxybenzoic acid), as a fluorescent probe with a large Stokes shift. HDBB had obvious excited state intramolecular proton transfer (ESIPT) and aggregation-induced emission (AIE) features. We elucidated the ESIPT characteristics of HDBB through the DFT approach. We also performed a molecular docking simulation between HDBB and HSA, showing that HDBB primarily bonded to HSA via hydrophobic force and hydrogen bonds. The FL intensities of HDBB with HSA concentrations had a linear range of 0.01-0.2 mg mL-1 (R2 = 0.9995), and the LOD was 1.104 µg mL-1. We also used the probe to detect HSA in urine, with spiked recoveries of 98.10-105.33%. Given its high selectivity and feasible synthesis, HDBB has potential applications in detecting HSA in real biological systems.

A versatile AIE probe with mitochondria targeting for dual-channel detection of superoxide anion and viscosity.

Abnormal viscosity and excessive superoxide anion (O2•-) levels in living cells often cause a series of biological dysfunction and oxidative damage. However, a great challenge remains in quickly and conveniently detecting the viscosity and O2•- levels in living cells. Herein, we fabricated a versatile aggregation-induced emission (AIE) probe with mitochondria targeting, DTPB, for dual-imaging of viscosity and O2•- level in living cells with two different channels. The obtained DTPB contained a diphenyl phosphinic acid unit responsive to O2•-, a unit with twisted intramolecular charge trans (TICT) function responsive to viscosity, and a pyridine cation unit with mitochondria targeting. The results showed that DTPB exhibited a remarkable response to viscosity with a near-infrared emission peak at 671 nm and was highly sensitive to O2•- levels with an emission peak at 587 nm. The dual-channel probe has great application prospects in the visual diagnosis of cancer and related diseases.

Copper nanoclusters stabilized by D-penicillamine for ultrasensitive and visual detection of oxytetracycline.

Copper nanoclusters (DPA@CuNCs) with red fluorescence were successfully synthesized by a one-step method based on D-penicillamine (DPA), which acted not only as a reducing agent but also as a stabilizer. The products were characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, particle-size analysis, ultraviolet-visible spectrophotometry, and fluorescence spectrometry. When the excitation wavelength was 280 nm, DPA@CuNCs emitted bright red fluorescence at 640 nm with a fluorescence quantum yield of 5.8 %. Due to the inner filter effect, oxytetracycline (OTC) effectively quenched the fluorescence of DPA@CuNCs, and then DPA@CuNCs were applied to the trace detection of OTC. The method showed a good linear range for OTC from 5 to 60 µmol/L, with a detection limit of 0.026 µmol/L and a correlation coefficient R2 of 0.9983. Moreover, a paper-based sensor for the visual detection of OTC has been developed, which can conveniently and rapidly distinguish the concentration ranges of OTC through the color changes of the test papers.

Aggregation-induced emission (AIE) nanoparticles based on γ-cyclodextrin and their applications in biomedicine.

Amphiphilic AIE nanoparticles (CD-TPE) were obtained by linking γ-cyclodextrin (γ-CD) and 1, 2-diphenyl-1, 2-(p-hydroxyphenyl)-ethylene (OH-TPE-OH) by an esterification reaction using hexamethylene diisocyanate (HMDI) in a one-step process. The CD-TPE was characterized by FTIR, 13C NMR, DSC, XRD, particle size analysis, TEM, and FL. The obtained CD-TPE had good water dispersibility and could self-assemble into AIE nanoparticles. The large cavity of CD-TPE provided convenient conditions for the loading of doxorubicin (DOX) and slow-release DOX with the loading and release rates of 67.4 % and 71.3 % (pH = 5.4), respectively. The DOX release kinetic model was suitable for the Bhaskar model. Cytotoxicity analysis and cell imaging of CD-TPE were performed, showing that CD-TPE has good biocompatibility and excellent cell imaging performance. Moreover, both in vitro and in vivo antitumor experiments showed that CD-TPE has promising applications in drug delivery.

Adsorption behavior of copper ions using crown ether-modified konjac glucomannan.

A novel supramolecular polysaccharide composite [KGM + DB18C6] was prepared from konjac glucomannan (KGM) and dibenzo-18-crown-6 (DB18C6) using ceric ammonium nitrate as initiator. The products were characterized by FTIR, TG, DSC, UV-Vis, XRD, solid-state 13C NMR, and SEM. Due to the introduction of crown ether, [KGM + DB18C6] showed good adsorption performance for Cu2+ in aqueous, and the maximum adsorption capacity was 194 mg/g under the optimal adsorption condition. The adsorption kinetics of [KGM + DB18C6] on Cu2+ could be described by the pseudo-second-order kinetic model. The adsorption isotherms of [KGM + DB18C6] on Cu2+ followed the dual-site Langmuir-Freundlich model. In addition, high recoveries of Cu2+ (from 82.65 to 88.47%), and low relative standard deviation (below 5.00%) were obtained by applying the product in real samples, indicating that [KGM + DB18C6] was a good absorbent for removing Cu2+ in wastewater.

Facile fabrication of MOF(Fe)@alginate aerogel and its application for a high-performance slow-release N-fertilizer.

In this work, a novel MOF(Fe)@NaAlg aerogels composite were fabricated by a facile method of ion cross-linking, and characterized via Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TG), X-ray photoelectron spectroscopy (XPS) and BET surface area analysis. The MOF(Fe)@NaAlg aerogels loaded by ammonium (NH4+) was prepare to the slow-release fertilizer (SRF). The adsorption capacity and swelling of MOF(Fe)@NaAlg(2:10) were 29.4 mg/g and 73 g/g, respectively. The swelling behaviors of MOF(Fe)@NaAlg(2:10) in different saline solutions were investigated. The release assessments confirmed the effective role of MOF(Fe) in slow-release property of the prepared formulation. Also, the prepared fertilizer formulation exhibited excellent water-retention capacity in soil. Therefore, they will have a great potential application in the field of agriculture.

Analysis of volatile compounds in traditional smoke-cured bacon(CSCB) with different fiber coatings using SPME.

The volatile compounds of Chinese traditional smoke-cured bacon (CSCB) were studied using SPMS-GC/MS. There were 48 volatile compounds identified and quantified, which belonged to several classes of chemical: 1 alkane, 16 aldehydes, 5 ketones, 9 alcohols, 4 thioethers and thiols, 3 furans and 10 phenols compounds. All the volatile compounds except for alkane was responsible for CSCB characteristic flavor. The major volatile compounds of CSCB came from smoking, oxidation and Maillard reaction, etc. Many volatile compounds were not reported in previous paper isolated by steam distillation method or nitrogen purge-and-steam distillation method on CSCB. It should be because of different method of isolating volatile substances from CSCB. Among the fibers tested, CAR/PDMS (carboxen/polydimethylsiloxane) fiber coating showed the highest area counts for most volatile compounds. CAR/PDMS coating extracted better those compounds whose linear retention indices (LRI) was lower than 926 (on average) and DVB/CAR/PDMS (divinylbenzene/carboxen/polydimethylsiloxane) those with higher LRI.