Multiplexed colorimetry collaborated with smartphone-based image analysis for simultaneous and fast visualization of dyes in both environmental and food samples.

In this work, a multiplexed colorimetric strategy was initiated for simultaneous and fast visualization of dyes using low-cost and easy-to-prepare indicator papers as sorbents. Response surface methodology (RSM) was employed to model statistically and optimize the process variables for dyes extraction and colorimetric assays. Multiplexed colorimetry was realized by virtue of synchronous color alignments from different dimensions of multiple dyes co-stained colorimetric cards under RSM-optimized conditions, and smartphone-based image analysis was subsequently performed from different modes to double-check the credibility of colorimetric assays. As concept-to-proof trials, simultaneous visualization of dyes in both beverages and simulated dye effluents was experimentally proved with results highly matched to HPLC or spiked amounts at RSM-predicted staining time as short as 50 s ∼3 min, giving LODs as low as 0.97 ± 0.22/0.18 ± 0.08 µg/mL (tartrazine/brilliant blue) for multiplexed colorimetry, which much lower than those obtained by single colorimetry. Since this is the first case to propose such a RSM-guided multiplexed colorimetric concept, it will provide a reference for engineering of other all-in-one devices which can realize synchronous visualization applications within limited experimental steps.

Combination of colorimetry, inner filter effect-induced fluorometry and smartphone­based digital image analysis: A versatile and reliable strategy for multi-mode visualization of food dyes.

Herein, a multi-mode visualization platform was initiated for in-situ detection of food dyes (FDs) by combining colorimetry, fluorometry and smartphone­based digital image analysis, in which water-dispersible quantum dots (QDs) were served as nanoprobes. Colorimetry was achieved by color comparison, while both fluorometry and fluorescence quantification were performed through inner filter effect (IFE)-induced fluorescence quenching, then color information (RGB & gray-scale values) of colorimetry and fluorometry was picked by a smartphone to reconstruct digitized alignments. Since IFE mechanism was concentration-dependent but did not rely on the interaction between fluorophore and quencher, the whole process of fluorescence response could be finished within 10 s, and both color gradients and fluorescence changes showed fine mappings to FDs concentrations in the range of 1.0 × 10-3∼0.035 mg/mL for brilliant blue, and 1.0 × 10-4∼0.1 mg/mL for Allura red and sunset yellow. As a proof-of-concept, the in-situ multi-mode visualization of these FDs in real beverages was experimentally proved to be highly feasible and reliable as compared with instrumental techniques like UV-vis/fluorescence spectrometry, along with HPLC. Finally, this strategy was extended to the multi-mode visualization of non-food dyes in three simulated wastewater samples with high credibility by contrast with the true additive amounts of model dyes.

Fabrication of betamethasone micro- and nanoparticles using supercritical antisolvent technology: In vitro drug release study and Caco-2 cell cytotoxicity evaluation.

Poor solubility limits the pharmacological activities of betamethasone (BM), including its anti-inflammatory and anti-allergic effects. To improve the aqueous solubility and dissolution rate of BM, supercritical antisolvent (SAS) technology was used to prepare BM microparticles and BM-polyvinylpyrrolidone (PVP) solid dispersion nanoparticles. The effects of temperature, pressure, solution feeding rate, and drug concentration on particle formation were investigated using both single-factor and orthogonal experimental methods, and the optimal preparation process was screened. The physicochemical properties of the BM particles were characterized by scanning electron microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, and X-ray diffraction. After the SAS process, the particle size was reduced significantly and the crystalline shape was altered, which considerably increased the solubility and dissolution rate of BM. Furthermore, the toxicity of BM to live cells was reduced because of the BM-PVP solid dispersions.

Colorimetry Combined with Inner Filter Effect-Based Fluorometry: A Versatile and Robust Strategy for Multimode Visualization of Food Dyes.

Herein, a strategy combining colorimetry and inner filter effect (IFE)-based fluorometry was developed for multimode visualization of food dyes (FDs) using CdTe quantum-dots-doped fluorescent indicator papers as a sample-to-answer device. Colorimetry was straightforwardly achieved by FDs extraction through electrostatic interaction and hydrophobic effect while fluorometry was implemented by IFE-induced fluorescence quenching. RGB/gray-scale values of colorimetry and fluorometry were furtherly picked by a smartphone application and applied to reconstruct color information-based digital image analysis for both direct alignments and linear regression analysis. The apparent color and fluorescence of FDs-bound indicator papers, together with their digitized color information, showed a good mapping to FDs concentrations in the range of 0-0.5 mg/mL for Sunset Yellow, 0-0.2 mg/mL for Allura Red, and 0-0.08 mg/mL for Brilliant Blue. As a proof of concept, the dosages of these FDs in real beverages and simulated dye effluents were deduced and cross-validated by different visualization modes, and finally double-checked by instrumental techniques such as spectrometric methods, high-performance liquid chromatography (HPLC), and mass spectroscopy (MS). The above findings concluded that (i) IFE mechanism is generally applicable to build fluorometric systems and (ii) cross validation of different visualization modes can markedly improve detection accuracy, which may provide references for design and fabrication of novel "lab-on-paper" devices for visualization applications with high reliability.

Fabrication of apigenin nanoparticles using antisolvent crystallization technology: A comparison of supercritical antisolvent, ultrasonic-assisted liquid antisolvent, and high-pressure homogenization technologies.

Flavonoids have many positive pharmacological properties, such as antioxidant, antitumor, and anti-inflammatory activities. However, factors such as low water solubility and low dissolution rate limit their use. To overcome their poor solubility, carrier-free apigenin (API) microparticles and nanoparticles were prepared using three types of antisolvent precipitation technologies: supercritical antisolvent (SCF) technology, ultrasonic-assisted liquid antisolvent (UAL) technology, and high-pressure homogenization (HPH) technology. All three technologies can produce uniform tiny particles. However, the API particles obtained using these different techniques show subtle differences in terms of physical and chemical properties and biological activity. The preparation, characterization, and potential use of API microparticles and nanoparticles to improve in vitro release were studied. The resulting API particles were investigated and compared using Fourier-transform infrared spectroscopy, differential scanning calorimetry, X-ray powder diffraction, and scanning electron microscopy. We determined the optimum conditions for SCF, UAL, and HPH technologies to produce API microparticles and nanoparticles. The antioxidant and antitumor properties of the API particles were also investigated. The results demonstrated that the reduced particle size of the APIs prepared via SCF, UAL, and HPH technologies contributed to the enhanced dissolution rate, which in turn enhanced API bioactivity.

Filter paper-based colorimetric analysis: An instrument-free strategy for semiquantitative naked-eye detection of food colorants.

A filter paper-based colorimetric strategy for instrument-independent visual detection of artificial food colorants (FCs) was developed in this study. Indicator papers were prepared via the one-step polycondensation of silane coupling agents onto glass microfiber filter papers, and colorimetric cards with a fine one-to-one correspondence between their colors and FCs concentrations were straightforward obtained by the extraction of FCs with indicator papers by virtue of electrostatic interaction and hydrophobic effect. Filter papers post-modified via such a simple way were proved to be of improved binding class selectivity and colorimetric sensitivity, allowing for in-situ colorimetric assay of FCs in an unprecedently wide range of applicable pH (1.0-12.0) with high reliability and fine versatility. Finally, the semiquantitative naked-eye determination of FCs (Allura red, brilliant blue and sunset yellow) in real-world drink samples was experimentally confirmed to be feasible by comparison with the findings of UV-vis absorption spectra, HPLC and mass spectra.

Semiquantitative naked-eye detection of synthetic food colorants using highly-branched pipette tip as an all-in-one device.

The existing strategies for the determination of synthetic food colorants (FCs) in manufactured foods are highly relied on specialized instruments and skilled personnel which are limited by the high technical threshold and instrumentation cost. Herein, highly branched pipette tips (PTs) were fabricated as a robust all-in-one device for high-performance extraction and visual detection of FCs via handy aspiration and dispensing procedures of pipette controller. The density of extraction groups and inner specific surface area of PTs greatly increased after facile physical coating and subsequent layer-by-layer branching reactions, and the maximum increment in binding capacity of PTs was exceeded 300 times at 8-10 iterations of branching layers, enabling the PTs to be colored just by short-time extraction of FCs and to achieve the instrument-independent visual detection of FCs by virtue of their outstanding PT-SPE performance. As a proof-of-concept, the in-situ PT-based solid phase extraction (PT-SPE) with high recoveries (from 91.73 ± 4.76% to 99.90 ± 4.14%) and semiquantitative naked-eye detection of FCs (Allura red and brilliant blue) in real beverages were experimentally demonstrated to be highly feasible by comparison with classical techniques like spectrophotometry, HPLC, and mass spectrometry.

Nanostructures assembly and the property of polysaccharide extracted from Tremella Fuciformis fruiting body.

Polysaccharides from fungi are good free radical scavengers. However, there are no enzymes digesting these polysaccharides in the human body, which limits the use of fungal polysaccharides. Therefore, it is of great significance to study the preparation methods of fungal polysaccharides to improve the utilization rate of fungal polysaccharides. In this paper, the acidic polysaccharide of Tremella fuciformis was extracted by boiling and precipitated by ethanol. The total sugar content obtained by freeze-drying after ion exchange chromatography purification was 93.6%. It is mainly composed of mannose, glucuronic acid, xylose and fucose. According to the peak area, the mass ratio of the substance is about 6.8:1:1.5:0.6, which indicates that TFP is a polysaccharide with mannose as its main chain and glucuronic acid, fucose and xylose as well as a small amount of glucose as the branch chain. Molecular weight is 1.86 × 106 Da. The existence of glucuronic acid endows polysaccharides with negative charge in aqueous solution and can be assembled into nanostructures with chitosan. By measuring the swelling property in aqueous, it shows the TFP separated from Tremella fuciformis fruits is suitable for drug controlled release.

Activated mitochondrial apoptosis in hESCs after dissociation involving the PKA/p-p53/Bax signaling pathway.

Human embryonic stem cells (hESCs) are highly fragile with massive cell death after dissociation into single cells, which seriously hampers their applications. The mechanism underlying the massive cell death after dissociation still remains elusive. Here, the expression of apoptosis-related proteins, cell survival and mitochondrial membrane potential in dissociated hESCs before and after the treatments with a protein kinase A (PKA) inhibitor H89 and p53 inhibitor Pifithrin α were investigated, respectively. Protein interactions were identified by immunoprecipitation and immunofluorescence. The results show that the dissociation causes Caspase-dependent apoptosis in hESCs mediated by mitochondrial pathway with the up-regulation of pro-apoptotic proteins, decrease in mitochondrial membrane potential and elevation in pro-apoptotic Cyto c release, which are obviously suppresses by H89. The dissociation-induced increase of phosphorylated p53 Ser15 (p-p53) is suppressed by Pifithrin α which also rescues the elevated levels of pro-apoptotic proteins in mitochondrial pathway. During the dissociation-induced apoptosis, PKA/p-p53/Bax signaling pathway is identified by immunoprecipitation and immunofluorescence showing the most likely interaction between them. These results indicate that dissociation induces mitochondrial apoptosis in hESCs involving PKA/p-p53/Bax signaling pathway, which not only give new insights into the apoptosis mechanism of dissociated hESCs, but also provide clues for developing potential strategies to promote hESC survival after dissociation.

Treatment of different parts of corn stover for high yield and lower polydispersity lignin extraction with high-boiling alkaline solvent.

The influence of different parts of corn stover on lignin extraction was investigated. Five kinds of lignin were isolated by the high boiling point solvent extraction from the whole corn stover and four different parts including leaf, husk, bark and pith. The optimal condition was obtained: 6.25 g/L NaOH, 140 °C, 1 h and 60% (v/v) 1,4-butanediol. The extracted lignins were then characterized. FT-IR analysis revealed that all of the lignins were typically herbaceous. The lignin extracted from husk contained more S unit. Gel permeation chromatography analysis showed that it was necessary to separate corn stover into different parts to obtain low polydispersity lignin. The SEM and FT-IR analysis proved that the lignin dissolution was related to the tightness structure presenting a positive correlation with hydrogen bond index.

Insight of Transmembrane Processes of Self-Assembling Nanotubes Based on a Cyclic Peptide Using Coarse Grained Molecular Dynamics Simulation.

Transmembrane self-assembling cyclic peptide (SCP) nanotubes are promising candidates for delivering specific molecules through cell membranes. The detailed mechanisms behind the transmembrane processes, as well as stabilization factors of transmembrane structures, are difficult to elucidate through experiments. In this study, the effects of peptide sequence and oligomeric state on the transmembrane capabilities of SCP nanotubes and the perturbation of embedded SCP nanotubes acting on the membrane were investigated based on coarse grained molecular dynamics simulation. The simulation results reveal that hydrophilic SCP oligomers result in the elevation of the energy barrier while the oligomerization of hydrophobic SCPs causes the reduction of the energy barrier, further leading to membrane insertion. Once SCP nanotubes are embedded, membrane properties such as density, thickness, ordering state and lateral mobility are adjusted along the radial direction. This study provides insight into the transmembrane strategy of SCP nanotubes and sheds light on designing novel transport systems.

[Preparation of curcumin-EC sustained-release composite particles by supercritical CO2 anti-solvent technology].

Curcumin-ethyl-cellulose (EC) sustained-release composite particles were prepared by using supercritical CO2 anti-solvent technology. With drug loading and yield of inclusion complex as evaluation indexes, on the basis of single factor tests, orthogonal experimental design was used to optimize the preparation process of curcumin-EC sustained-release composite particles. The experiments such as drug loading, yield, particle size distribution, electron microscope analysis (SEM) , infrared spectrum (IR), differential scanning calorimetry (DSC) and in vitro dissolution were used to analyze the optimal process combination. The orthogonal experimental optimization process conditions were set as follows: crystallization temperature 45 degrees C, crystallization pressure 10 MPa, curcumin concentration 8 g x L(-1), solvent flow rate 0.9 mL x min(-1), and CO2 velocity 4 L x min(-1). Under the optimal conditions, the average drug loading and yield of curcumin-EC sustained-release composite particles were 33.01% and 83.97%, and the average particle size of the particles was 20.632 µm. IR and DSC analysis showed that curcumin might complex with EC. The experiments of in vitro dissolution showed that curcumin-EC composite particles had good sustained-release effect. Curcumin-EC sustained-release composite particles can be prepared by supercritical CO2 anti-solvent technology.