Injection by Hydrostatic Pressure in Conjunction with Electrokinetic Force on a Microfluidic Chip

A simple method was developed for injecting a sample on a cross-form microfluidic chip by means of hydrostatic pressure combined with electrokinetic forces. The hydrostatic pressure was generated simply by adjusting the liquid level in different reservoirs without any additional driven equipment such as a pump. Two dispensing strategies using a floating injection and a gated injection, coupled with hydrostatic pressure loading, were tested. The fluorescence observation verified the feasibility of hydrostatic pressure loading in the separation of a mixture of fluorescein sodium salt and fluorescein isothiocyanate. This method was proved to be effective in leading cells to a separation channel for single cell analysis

Cell-imprinted polydimethylsiloxane for the selective cell adhesion

Cell adhesion is the basis for some cell isolation methods, and is influenced by both of the biochemical and topographic characteristics of the substrates. Herein, based on cell imprinting and click chemistry, we have developed a cell-imprinted polydimethylsiloxane (PDMS) with aptamer functionalization (APT-CIS). The atom force microscopic analysis results showed that the hierarchical structure matching well with the target cells is successfully introduced on the surface of the APT-CIS. By using the synergistic effects of hierarchical structure and aptamer affinity, the APT-CIS was successfully used for the selective cell adhesion, and 93.9% +/- 0.8% of the captured cells could then be released. Thus, the APT-CIS holds promise in selective cell isolation and sorting fields. (C) 2018 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved

cellimprintedpolydimethylsiloxanefortheselectivecelladhesion

Cell adhesion is the basis for some cell isolation methods, and is influenced by both of the biochemical and topographic characteristics of the substrates. herein, based on cell imprinting and click chemistry, we have developed a cell-imprinted polydimethylsiloxane (pdms) with aptamer functionalization (apt-cis). the atom force microscopic analysis results showed that the hierarchical structure matching well with the target cells is successfully introduced on the surface of the apt-cis. by using the synergistic effects of hierarchical structure and aptamer affinity, the apt-cis was successfully used for the selective cell adhesion, and 93.9% +/- 0.8% of the captured cells could then be released. thus, the apt-cis holds promise in selective cell isolation and sorting fields. (c) 2018 chinese chemical society and institute of materia medica, chinese academy of medical sciences. published by elsevier b.v. all rights reserved

cellimprintedpolydimethylsiloxanefortheselectivecelladhesion

Cell adhesion is the basis for some cell isolation methods, and is influenced by both of the biochemical and topographic characteristics of the substrates. herein, based on cell imprinting and click chemistry, we have developed a cell-imprinted polydimethylsiloxane (pdms) with aptamer functionalization (apt-cis). the atom force microscopic analysis results showed that the hierarchical structure matching well with the target cells is successfully introduced on the surface of the apt-cis. by using the synergistic effects of hierarchical structure and aptamer affinity, the apt-cis was successfully used for the selective cell adhesion, and 93.9% +/- 0.8% of the captured cells could then be released. thus, the apt-cis holds promise in selective cell isolation and sorting fields. (c) 2018 chinese chemical society and institute of materia medica, chinese academy of medical sciences. published by elsevier b.v. all rights reserved

Spontaneous transient states of fronto-temporal and default-mode networks altered by suicide attempt in major depressive disorder

Major depressive disorder (MDD) is associated with increased suicidality, and it’s still challenging to identify suicide in clinical practice. Although suicide attempt (SA) is the most relevant precursor with multiple functional abnormalities reported from neuroimaging studies, little is known about how the spontaneous transient activated patterns organize and coordinate brain networks underlying SA. Thus, we obtained resting-state magnetoencephalography data for two MDD subgroups of 44 non-suicide patients and 34 suicide-attempted patients, together with 49 matched health-controls. For the source-space signals, Hidden Markov Model (HMM) helped to capture the sub-second dynamic activity via a hidden sequence of finite number of states. Temporal parameters and spectral activation were acquired for each state and then compared between groups. Here, HMM states characterized the spatiotemporal signatures of eight networks. The activity of suicide attempters switches more frequently into the fronto-temporal network, as the time spent occupancy of fronto-temporal state is increased and interval time is decreased compared with the non-suicide patients. Moreover, these changes are significantly correlated with Nurses’ Global Assessment of Suicide Risk scores. Suicide attempters also exhibit increased state-wise activations in the theta band (4-8 Hz) in the posterior default mode network centered on posterior cingulate cortex, which can’t be detected in the static spectral analysis. These alternations may disturb the time allocations of cognitive control regulations and cause inflexible decision making to SA. As the better sensitivity of dynamic study in reflecting SA diathesis than the static is validated, dynamic stability could serve as a potential neuronal marker for SA

Fabrication of two-weir structure-based packed columns for on-chip solid-phase extraction of DNA

Microchip-based packed column SPE of DNA was performed using the microfabricated two-weir structure within a microchannel. We developed two methods to fabricate the two-weir structured glass chips: a "two-side etching/alignment" method and a simplified "one-side/two-step etching" method. The former rnethod required a straightforward alignment step, while the latter approach comprised a simplified wet etching process using paraffin wax as the temporary protective layer. Both methods were convenient and rapid as compared to the previous approaches. Through a reversibly sealed bead-introduction channel, beads can be fed into or out of the chip columns, thus enabling refreshment of the packing materials. Using the proposed chip columns, highly efficient,lambda-DNA extractions (average recovery > 80%) were performed with good chip-to-chip reproducibility (RSD < 10%). The on-chip SPE procedure was completed within 15 min at the flow rate of 3 mu L/min and the bulk of the loaded DNA was eluted within a small volume of similar to 8 mu L. Application of the microchip-based packed columns was demonstrated by purifying PCR-amplifiable genomic DNA from human hepatocellular carcinoma (HepG2) cells and human whole blood samples

Studying drug-plasma protein interactions by two-injector microchip electrophoresis frontal analysis

We developed a simple, rapid, and sensitive two-injector microchip electrophoresis frontal analysis (MCE-FA) method for studying drug-plasma protein interactions. In this method, large volumes of a reference sample and drug-plasma protein mixture were simultaneously introduced into the respective sections of the microchannel through the separated injectors and then electrophoresed. Since the reference sample did not meet with the interacting species during migration, it could be used as an external standard. The interaction between heparin and HSA was quantitatively characterized as a model system. The binding constant was found to be (1.53 +/- 0.01) X 10(4) M-1

Spontaneous beta power, motor-related beta power and cortical thickness in major depressive disorder with psychomotor disturbance

Introduction: The psychomotor disturbance is a common symptom in patients with major depressive disorder (MDD). The neurological mechanisms of psychomotor disturbance are intricate, involving alterations in the structure and function of motor-related regions. However, the relationship among changes in the spontaneous activity, motor-related activity, local cortical thickness, and psychomotor function remains unclear. Method: A total of 140 patients with MDD and 68 healthy controls performed a simple right-hand visuomotor task during magnetoencephalography (MEG) scanning. All patients were divided into two groups according to the presence of psychomotor slowing. Spontaneous beta power, movement-related beta desynchronization (MRBD), absolute beta power during movement and cortical characteristics in the bilateral primary motor cortex were compared using general linear models with the group as a fixed effect and age as a covariate. Finally, the moderated mediation model was tested to examine the relationship between brain metrics with group differences and psychomotor performance. Results: The patients with psychomotor slowing showed higher spontaneous beta power, movement-related beta desynchronization and absolute beta power during movement than patients without psychomotor slowing. Compared with the other two groups, significant decreases were found in cortical thickness of the left primary motor cortex in patients with psychomotor slowing. Our moderated mediation model showed that the increased spontaneous beta power indirectly affected impaired psychomotor performance by abnormal MRBD, and the indirect effects were moderated by cortical thickness. Conclusion: These results suggest that patients with MDD have aberrant cortical beta activity at rest and during movement, combined with abnormal cortical thickness, contributing to the psychomotor disturbance observed in this patient population