Microfluidic devices for cell cultivation and proliferation

Microfluidic technology provides precise, controlled-environment, cost-effective, compact, integrated, and high-throughput microsystems that are promising substitutes for conventional biological laboratory methods. In recent years, microfluidic cell culture devices have been used for applications such as tissue engineering, diagnostics, drug screening, immunology, cancer studies, stem cell proliferation and differentiation, and neurite guidance. Microfluidic technology allows dynamic cell culture in microperfusion systems to deliver continuous nutrient supplies for long term cell culture. It offers many opportunities to mimic the cell-cell and cell-extracellular matrix interactions of tissues by creating gradient concentrations of biochemical signals such as growth factors, chemokines, and hormones. Other applications of cell cultivation in microfluidic systems include high resolution cell patterning on a modified substrate with adhesive patterns and the reconstruction of complicated tissue architectures. In this review, recent advances in microfluidic platforms for cell culturing and proliferation, for both simple monolayer (2D) cell seeding processes and 3D configurations as accurate models of in vivo conditions, are examined

Advances in Microfluidics and Lab-on-a-Chip Technologies

Advances in molecular biology are enabling rapid and efficient analyses for effective intervention in domains such as biology research, infectious disease management, food safety, and biodefense. The emergence of microfluidics and nanotechnologies has enabled both new capabilities and instrument sizes practical for point-of-care. It has also introduced new functionality, enhanced sensitivity, and reduced the time and cost involved in conventional molecular diagnostic techniques. This chapter reviews the application of microfluidics for molecular diagnostics methods such as nucleic acid amplification, next-generation sequencing, high resolution melting analysis, cytogenetics, protein detection and analysis, and cell sorting. We also review microfluidic sample preparation platforms applied to molecular diagnostics and targeted to sample-in, answer-out capabilities

Fibers for hearts: A critical review on electrospinning for cardiac tissue engineering

Cardiac cell therapy holds a real promise for improving heart function and especially of the chronically failing myocardium. Embedding cells into 3D biodegradable scaffolds may better preserve cell survival and enhance cell engraftment after transplantation, consequently improving cardiac cell therapy compared with direct intramyocardial injection of isolated cells. The primary objective of a scaffold used in tissue engineering is the recreation of the natural 3D environment most suitable for an adequate tissue growth. An important aspect of this commitment is to mimic the fibrillar structure of the extracellular matrix, which provides essential guidance for cell organization, survival, and function. Recent advances in nanotechnology have significantly improved our capacities to mimic the extracellular matrix. Among them, electrospinning is well known for being easy to process and cost effective. Consequently, it is becoming increasingly popular for biomedical applications and it is most definitely the cutting edge technique to make scaffolds that mimic the extracellular matrix for industrial applications. Here, the desirable physico-chemical properties of the electrospun scaffolds for cardiac therapy are described, and polymers are categorized to natural and synthetic.Moreover, the methods used for improving functionalities by providing cells with the necessary chemical cues and a more in vivo- like environment are reported

In-Syringe Electrokinetic Protein Removal from Biological Samples prior to Electrospray Ionization Mass Spectrometry

Here, an electrokinetic extraction (EkE) syringe is presented allowing for on‐line electrokinetic removal of serum proteins before ESI-MS. The proposed concept is demonstrated by the determination of pharmaceuticals from human serum within minutes, with sample preparation limited to a 5× dilution of the sample in the background electrolyte (BGE) and application of voltage, both of which can be performed in‐syringe. Signal enhancements of 3.6-32 fold relative to direct infusion of diluted serum and up to 10.8 fold enhancement, were obtained for basic and acidic pharmaceuticals, respectively. Linear correlations for the basic drugs by EkE‐ESI‐MS/MS were achieved, covering the necessary clinical range with LOQs of 5.3, 7.8, 6.1, and 17.8 ng mL-1 for clomipramine, chlorphenamine, pindolol, and atenolol, respectively. For the acidic drugs, the EkE‐ESI‐MS LOQs were 3.1 μg mL-1 and 2.9 μg mL-1 for naproxen and paracetamol, respectively. The EkE‐ESI‐MS and EkE‐ESI‐MS/MS methods showed good accuracy (%found of 81 % to 120 %), precision (≤20 %), and linearity (r>0.997) for all the studied drugs in spiked serum samples

Design, characterization and application of a novel mono-layer pin-microvalve for microfluidic devices

Valves are one of the key components in microfluidic devices to control the fluid flow. In this paper we introduce a novel manual pin-valve which can operate in both analogue (partially close) and digital (on/off) states. We also demonstrate implementation of this pin-valve in a hydrodynamic flow focusing (HFF) device

In-syringe electrokinetic ampholytes focusing coupled with electrospray ionization mass spectrometry

A 25 μL analytical glass syringe has been used for isoelectric focusing (IEF) utilizing the stainless-steel needle and plunger as electrodes. The generation of protons and hydroxyl ions at the electrodes facilitated a neutralization reaction boundary (NRB) mechanism to focus different amphoteric compounds, such as hemoglobin, bovine serum albumin, R-phycoerythrin, and histidine, within minutes. After optimization of different experimental parameters affecting the IEF process and the coupling of the IEF syringe with electrospray ionization mass spectrometry (ESI-MS), a BGE composed of NH4Ac, 1.0 mM, pH 4.0, in 70.0% (v/v) acetonitrile was used for the IEF of histidine. A voltage of −200 V was applied for 5.0 min to accomplish the IEF and increased to -400 V during the infusion to ESI-MS at a flow rate of 4.0 μL/min. The coaxial sheath liquid consisting of 0.2% (v/v) formic acid was added at 4.0 μL/min. The detection limit was found to be 2.2 μg/mL and a nonlinear quadratic fit calibration curve was constructed for histidine over the range of 4.0-64.0 μg/mL with a correlation coefficient (r) = 0.9998. The determination of histidine in spiked urine samples as relevant for the diagnosis of histidinemia was demonstrated by the IEF syringe-ESI-MS system with accuracy from 88.25% to 102.16% and a relative standard deviation less than 11%

Automated liquid-liquid extraction of organic compounds from aqueous samples using a multifunction autosampler syringe

Liquid-liquid extraction is one of the most widely used and simplest sample preparation techniques. However, consumption of large volumes of organic solvent and manual handling are two major drawbacks of this technique. A multifunction autosampler syringe is introduced which permits automated liquid-liquid extraction in an enclosed operating environment, with low consumption of organic solvents. The device described herein features a micromixer function in addition to common autosampler syringe features like accurate and precise aspirating and dispensing. To test the functionality of the micromixer syringe, manual extraction of caffeine from a tea infusion and semi-automated extraction of dichloroethane from water were carried out. Excellent recoveries of caffeine from a tea infusion (89% recovery with 1.3% RSD) and dichloroethane from water (107% recovery with 10% RSD) were obtained. Two automated workflows were tested using the micromixer syringe mounted in a laboratory autosampler. Standalone automated micro liquid-liquid extraction was performed for sample preparation of selected polychlorinated biphenyl (PCB) congeners prior to comprehensive two-dimensional gas chromatography - electron capture detection analysis. Extraction of PCBs using the described approach used substantially less solvent than a validated solid-phase extraction approach whilst delivering equivalent results for samples with high-level PCBs. Finally, fully automated extraction and GC-MS analysis of polynuclear aromatic hydrocarbons (PAHs) from water samples was performed. Mean recoveries of extraction for PCB and PAH analysis were > 70% using 4 min automated liquid-liquid extractions

Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips (2014–2016)

One of the most cited limitations of capillary (and microchip) electrophoresis is the poor sensitivity. This review continues to update this series of biennial reviews, first published in Electrophoresis in 2007, on developments in the field of on‐line/in‐line concentration methods in capillaries and microchips, covering the period July 2014–June 2016. It includes developments in the field of stacking, covering all methods from field amplified sample stacking and large volume sample stacking, through to isotachophoresis, dynamic pH junction, and sweeping. Attention is also given to on‐line or in‐line extraction methods that have been used for electrophoresis