The presence and quantity of rare cells in the bloodstream of cancer patients provide a potentially accessible source for the early detection of invasive cancer and for monitoring the treatment of ...advanced diseases. The separation of rare cells from peripheral blood, as a "virtual and real-time liquid biopsy", is expected to replace conventional tissue biopsies of metastatic tumors for therapy guidance. However, technical obstacles, similar to looking for a needle in a haystack, have hindered the broad clinical utility of this method. In this study, we developed a multistage microfluidic device for continuous label-free separation and enrichment of rare cells from blood samples based on cell size and deformability. We successfully separated tumor cells (MCF-7 and HeLa cells) and leukemic (K562) cells spiked in diluted whole blood using a unique complementary combination of inertial microfluidics and steric hindrance in a microfluidic system. The processing parameters of the inertial focusing and steric hindrance regions were optimized to achieve high-throughput and high-efficiency separation, significant advantages compared with existing rare cell isolation technologies. The results from experiments with rare cells spiked in 1% hematocrit blood indicated >90% cell recovery at a throughput of 2.24 × 10(7) cells min(-1). The enrichment of rare cells was >2.02 × 10(5)-fold. Thus, this microfluidic system driven by purely hydrodynamic forces has practical potential to be applied either alone or as a sample preparation platform for fundamental studies and clinical applications.
Neuronal cell microengineering involving micropatterning and polydimethylsiloxane (PDMS) microfluidics enables promising advances in microscale neuron control. However, a facile methodology for the ...precise and effective manipulation of neurons on a cell-repellent PDMS substrate remains challenging. Herein, a simple and straightforward strategy for neuronal cell patterning and neuronal network construction on PDMS based on microfluidics-assisted modification of functionalized Pluronic is described. The cell patterning process simply involves a one-step microfluidic modification and routine
in vitro
culture. It is demonstrated that multiple types of neuronal cell arrangements with various spatial profiles can be conveniently produced using this patterning tool. The precise control of neuronal cells with high patterning fidelity up to single cell resolution, as well as high adhesion and differentiation, is achieved too. Furthermore, neuronal network construction using the respective cell population and single cell patterning prove to be applicable. This achievement provides a convenient and feasible methodology for engineering neuronal cells on PDMS substrates, which will be useful for applications in many neuron-related microscale analytical research fields, including cell engineering, neurobiology, neuropharmacology, and neuronal sensing.
We present straightforward neuron patterning and neuronal network construction on polydimethylsiloxane based on functionalized Pluronic modification using microfluidics-guided flow deposition.
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•PLA and Au@PDA NPs blend electrospinning to produce PLA-Au@PDA nanofibers.•In situ assembly of well-dispersed Ag nanoparticles to produce PLA-Au@PDA@Ag nanofibers.•PLA-Au@PDA@Ag ...nanofibers exhibited good hydrophilicity and excellent antibacterial abilities.
Nanofibrous membranes which exhibit bacteriostatic functions are a good strategy to prevent microorganisms from adhering to the surface of biomaterials. Here, we report the synthesis of such a nanofibrous membrane which can be applied to biological coatings to reduce bacteriostatic functionality. Ascorbic acid was utilized to reduced chloroauric acid to gold nanoparticles (AuNPs). Dopamine was then polymerized upon AuNP surfaces by ultrasound-assistance, to synthesize core-shell structured polydopamine-coated AuNPs (Au@PDA NPs). The Au@PDA NPs were then mixed with polylactic acid (PLA) for electrospinning into cylindrical nanofibers (136.6 nm diameter). PLA-Au@PDA nanofibrous membranes were finally immersed in silver nitrate for in situ reduction into a silver nanoparticle (AgNP) coating to yield PLA-Au@PDA@Ag nanofibers. The PLA-Au@PDA@Ag nanofibers were characterized based on field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and contact angle analyses. The antibacterial properties of the PLA-Au@PDA@Ag nanofibers were examined based on the optical density absorbance of bacterial cell suspensions, traditional colony plate counts, zone inhibition analyses, and field-emission scanning electron microscopy. Escherichia coli and Staphylococcus aureaus respectively served as Gram negative and positive bacterial models of industrial relevance. The data conclusively illustrates the antimicrobial and biomedical applications of PLA-Au@PDA@Ag nanofibers.
Controlling selectivity between homochiral and heterochiral reaction pathways on surfaces remains a great challenge. Here, competing reactions of a prochiral alkyne on Ag(111): two-dimensional (2D) ...homochiral Glaser coupling and heterochiral cross-coupling with a Bergman cyclization step have been examined. We demonstrate control strategies in steering the reactions between the homochiral and heterochiral pathways by tuning the precursor substituents and the kinetic parameters, as confirmed by high-resolution scanning probe microscopy (SPM). Control experiments and density functional theory (DFT) calculations reveal that the template effect of organometallic chains obtained under specific kinetic conditions enhances Glaser coupling between homochiral molecules. In contrast, for the reaction of free monomers, the kinetically favorable reaction pathway is the cross-coupling between two heterochiral molecules (one of them involving cyclization). This work demonstrates the application of kinetic control to steer chiral organic coupling pathways at surfaces.
Biothiols, such as glutathione (GSH) and cysteine (Cys), play important roles in many physiological processes, and variations in their levels are related to different diseases. Many fluorescence ...probes have been developed to understand the function of biothiols, but only few of such probes can detect both Cys and GSH. Herein, a new strategy for specific colorimetric and fluorescent detection of Cys and GSH by different cascade reactions was developed. By utilizing this strategy, we designed and synthesized two fluorescent probes, namely, CR1 and CR2, for detection of Cys and GSH under physiological conditions. CR1 contains a stronger electron-withdrawing substituent group and provides high selectivity and sensitivity for Cys and GSH. This probe is based on the mechanism of Cys-induced native-chemical-ligation-cyclization and GSH-induced transthioesterification–cyclization cascade reactions, with detection limits of 0.029 and 0.371 μM, respectively. CR1 can be successfully applied for imaging Cys and GSH in living cells with low cell toxicity.
A new dual-channel trinal-site fluorescent probe CR1 for Cys and GSH was developed based on different cascade reactions. Display omitted
•A cascade reaction-based trinal-site probe CR1 was developed for Cys and GSH.•The probe can detect both Cys and GSH with detection limits of 0.029 and 0.371 μM, respectively.•The probe can be used for imaging Cys and GSH in living cells with low cell toxicity.
The flow channel structure is the main factor affecting the hydraulic performance, anti-clogging and energy dissipation performance of drip irrigation tape. Proper exploring of the ...performance-related but hard-to-measure structure parameters in the flow channel emitter of drip irrigation tape is imperative. However, the traditional studying methods may lead to large systematic errors and human errors, resulting in inaccurate estimations of the parameters and an unreasonable design. This paper aims to find an effective way to optimize the most significant channel structural parameter through studying 18 kinds of drip irrigation belts commonly used in the agricultural irrigation field. Unigraphics NX and Spaceclaim were applied to measure the eight main structure parameters of the selected drip irrigation tapes. The one critical parameter that affects the emitter hydraulic performance—tooth spacing—was found by Principal Component Analysis (PCA). Therefore, we designed three plans where the tooth spacing decreased by 0.1, 0.2, and 0.29 mm to 1.36, 1.26, and 1.17 mm, respectively, and, finally, formed two types of flow channels. Flow channel 1 with a tooth base is represented by Plan 1 and Plan 2, and flow channel 2 without a tooth base is represented by Plan 3. Then, computational fluid dynamics (CFD) was used to simulate the flow characteristics of the emitters in the three plans. The results demonstrate that flow channel 2 without a tooth base, represented by Plan 3, has a greater kinetic energy and hydraulic performance than flow channel 1. Compared with the control group, the changes in Plan 3 were the most obvious, with the changes in the flow index, flow coefficient, and average flow rate by −14.50%, −5.08%, and 12.50%, respectively. The flow indexes in the three plans are all less than 0.5, while the smallest of Plan 3 is 0.395. Therefore, the hydraulic performance of flow channel 2 represented by Plan 3 is better. The narrowing of the tooth spacing makes the space for vortexing between the serrated teeth smaller. The flow velocity in Plan 3 is generally increased by 3 m/s from 2.3 to 4.1 m/s, becoming more uniform. Due to a high velocity of the water flow and less vortexing, the deposition of suspended solids in the flow channel is avoided to a certain extent, and for the flow channel in Plan 3, the improvement in the hydraulic performance is greater than the reduction in the energy dissipation performance. The ratio of the decrease in the flow index to the increase in the average outflow of the emitter in Plan 3 is 1.16:1. In conclusion, the overall performance of Plan 3 is optimal for all schemes. Flow channel 2 can improve the hydraulic performance and reduce the production costs. Therefore, this study could provide a theoretical induction for inner drip irrigation tape application and production.
The influence of chloride ion (Cl−) concentration on the corrosion mechanism of WC–MgO composites has been studied in this work. The results suggest that the corrosion resistance of WC–MgO composite ...decreases first and then increases with the increase in Cl− concentration. Solution conductivity and dissolved oxygen content are the main influence factors. The solution conductivity determines the charge transfer process, and the dissolved oxygen determines the cathodic oxygen absorption reaction. The corrosion characteristic is typical pitting corrosion. Meanwhile, the corrosion mechanism contains an oxidation process of the WC matrix and the dissolution destruction of the MgO toughening phase. The formation of the WO3 corrosion layer hinders the general corrosion to protect the inner material. However, the dissolution of MgO induces the initiation of pitting. The local alkaline caused by MgO dissolution promotes the dissolution of the WC matrix, which leads to the expansion of pitting.
Rice-like polymeric nanoparticles composed of a new redox-responsive polymer, poly(ethylene glycol)-
b-poly(lactic acid) (MPEG-SS-PLA), were prepared to carry paclitaxel for glutathione ...(GSH)-regulated drug delivery.
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► A new redox-sensitive polymer was synthesized, and its paclitaxel (PTX)-loaded nanoparticles (NPs) were prepared. ► HPLC analysis reveals that the PTX-loaded NPs had a high encapsulation efficiency, long-term stability, and can rapidly released PTX under the stimulus of glutathione. ►
In vitro cytotoxicity and cellular uptake assays demonstrate that the NPs had low cytotoxicity, high cytocompatibility, and an ability to assist the endocytotic action of an antitumor drug.
Rice-like polymeric nanoparticles (NPs) composed of a new redox-responsive polymer, poly(ethylene glycol)-
b-poly(lactic acid) (MPEG-SS-PLA), were prepared to carry paclitaxel (PTX) for glutathione (GSH)-regulated drug delivery. The PTX-loaded MPEG-SS-PLA NPs were fabricated using an optimized oil-in-water emulsion/solvent evaporation method. The size and morphology of the prepared NPs were characterized by scanning electron microscopy (SEM). The SEM results demonstrate that the NPs were dispersed as individual particles and were rice-shaped. The PTX loading efficiency,
in vitro release, and stability of the NPs were analyzed by high-performance liquid chromatography (HPLC). The HPLC results revealed that the NPs released almost 90% PTX within 96
h when GSH presented at intracellular concentrations, whereas only a very small PTX amount was released at plasma GSH levels. The
in vitro cytotoxicities of the NPs against A549, MCF-7, and HeLa carcinoma cells were assessed using a standard methyl thiazolyl tetrazoliun (MTT) assay. The MTT assay results show that the NPs caused concentration- and time-dependent changes in cell viability. To investigate the cellular uptake of the PTX-loaded NPs, visual endocytosis assay was performed using the fluorescent dye coumarin-6 as a model drug. The endocytosis assay results reveal rapid penetration and intracellular accumulation of coumarin-6-loaded NPs, as well as rapid coumarin-6 dispersion from the NPs. Overall, these findings establish that the NPs containing the synthesized redox-responsive polymer MPEG-SS-PLA can be used as potential carrier systems for antitumor drug delivery.
Although previous studies showed that women’s menopause-related symptoms varied in different ethnic groups and countries, and were affected by specific social and cultural factors, few studies have ...been conducted to explore menopause-related symptoms and its influencing factors in middle-aged women among ethnic groups in China. This study aimed to explore the characteristics of menopause-related symptoms and its influencing factors among Mosuo, Yi, and Han women in Yongning area of Yunnan province, China. A cross-cultural design by snowball sampling method was used to recruit 208 women aged 40–60 from Yongning Township, Ninglang County, Yunnan province, China. The 11-item Menopause Rating Scale (MRS) was used to assess menopause-related symptoms. Compared with Yi and Han women, Mosuo women were accorded the highest family status. Multiple linear regression analyses showed that ethnicity, age, family support, and family decision-making patterns were associated with the severity of menopause-related symptoms. Yi and Han women had more severe menopause-related symptoms than Mosuo women. Among the three groups, women living in “female-dominated” and “co-deliberated” households had significantly lower scores of menopause-related symptoms than those in “male-dominated” households. This study indicates that menopause-related symptoms vary among middle-aged women in different ethnic groups. A higher level of female status in the family and family support may be protective factors of menopause-related symptoms in middle-aged women.
Triarylboron‐based Lewis acids as fluoride sensors face a stimulating academic challenge because of the high hydration enthalpy of fluoride, and are usually influenced by a competing response for ...cyanide ion. Herein, we present a new triarylborane functionalized by a metal‐ion ligand, di‐(2‐picolyl)‐N‐(2‐quinolinylmethyl)amine, with subsequent metalation. In aqueous solution, this triarylborane (QB) can capture fluoride and cyanide anions through chelation induced by the synergy of boron and metal ions. Moreover, this triarylborane moiety acts as a fluorescent reporter of the binding, allowing for discrimination between fluoride and cyanide anions through dual‐channel fluorescence changes. The different chelation models and fluorogenic responses of this sensor toward F− and CN− were verified by the single‐crystal structures of 2‐to‐2 adduct for KCN and 1‐to‐1 for KF.
Boron and metal ion teamwork: A chemosensor is constructed by conjugating a metal‐ion ligand to a triarylborane. In aqueous solution, this conjugate can discriminate between fluoride and cyanide anions through different chelation induced by the synergy of boron and metal ions, which was verified by the single‐crystal structures of the 2‐to‐2 adduct for KCN and 1‐to‐1 for KF.
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