Two dimensional electrophysiological characterization of human pluripotent stem cell-derived cardiomyocyte system.

Stem cell-derived cardiomyocytes provide a promising tool for human developmental biology, regenerative therapies, disease modeling, and drug discovery. As human pluripotent stem cell-derived cardiomyocytes remain functionally fetal-type, close monitoring of electrophysiological maturation is critical for their further application to biology and translation. However, to date, electrophysiological analyses of stem cell-derived cardiomyocytes has largely been limited by biologically undefined factors including 3D nature of embryoid body, sera from animals, and the feeder cells isolated from mouse. Large variability in the aforementioned systems leads to uncontrollable and irreproducible results, making conclusive studies difficult. In this report, a chemically-defined differentiation regimen and a monolayer cell culture technique was combined with multielectrode arrays for accurate, real-time, and flexible measurement of electrophysiological parameters in translation-ready human cardiomyocytes. Consistent with their natural counterpart, amplitude and dV/dtmax of field potential progressively increased during the course of maturation. Monolayer culture allowed for the identification of pacemaking cells using the multielectrode array platform and thereby the estimation of conduction velocity, which gradually increased during the differentiation of cardiomyocytes. Thus, the electrophysiological maturation of the human pluripotent stem cell-derived cardiomyocytes in our system recapitulates in vivo development. This system provides a versatile biological tool to analyze human heart development, disease mechanisms, and the efficacy/toxicity of chemicals

Microchips and their significance in isolation of circulating tumor cells and monitoring of cancers

In micro-fluid systems, fluids are injected into extremely narrow polymer channels in small amounts such as micro-, nano-, or pico-liter scales. These channels themselves are embedded on tiny chips. Various specialized structures in the chips including pumps, valves, and channels allow the chips to accept different types of fluids to be entered the channel and along with flowing through the channels, exert their effects in the framework of different reactions. The chips are generally crystal, silicon, or elastomer in texture. These highly organized structures are equipped with discharging channels through which products as well as wastes of the reactions are secreted out. A particular advantage regarding the use of fluids in micro-scales over macro-scales lies in the fact that these fluids are much better processed in the chips when they applied as micro-scales. When the laboratory is miniaturized as a microchip and solutions are injected on a micro-scale, this combination makes a specialized construction referred to as "lab-on-chip". Taken together, micro-fluids are among the novel technologies which further than declining the costs; enhancing the test repeatability, sensitivity, accuracy, and speed; are emerged as widespread technology in laboratory diagnosis. They can be utilized for monitoring a wide spectrum of biological disorders including different types of cancers. When these microchips are used for cancer monitoring, circulatory tumor cells play a fundamental role

Label-free enrichment of adrenal cortical progenitor cells using inertial microfluidics.

Passive and label-free isolation of viable target cells based on intrinsic biophysical cellular properties would allow for cost savings in applications where molecular biomarkers are known as well as potentially enable the separation of cells with little-to-no known molecular biomarkers. We have demonstrated the purification of adrenal cortical progenitor cells from digestions of murine adrenal glands utilizing hydrodynamic inertial lift forces that single cells and multicellular clusters differentially experience as they flow through a microchannel. Fluorescence staining, along with gene expression measurements, confirmed that populations of cells collected in different outlets were distinct from one another. Furthermore, primary murine cells processed through the device remained highly viable and could be cultured for 10 days in vitro. The proposed target cell isolation technique can provide a practical means to collect significant quantities of viable intact cells required to translate stem cell biology to regenerative medicine in a simple label-free manner

Accomplishments and challenges in stem cell imaging in vivo.

Stem cell therapies have demonstrated promising preclinical results, but very few applications have reached the clinic owing to safety and efficacy concerns. Translation would benefit greatly if stem cell survival, distribution and function could be assessed in vivo post-transplantation, particularly in patients. Advances in molecular imaging have led to extraordinary progress, with several strategies being deployed to understand the fate of stem cells in vivo using magnetic resonance, scintigraphy, PET, ultrasound and optical imaging. Here, we review the recent advances, challenges and future perspectives and opportunities in stem cell tracking and functional assessment, as well as the advantages and challenges of each imaging approach

Microtechnologies for Cell Microenvironment Control and Monitoring

A great breadth of questions remains in cellular biology. Some questions cannot be answered using traditional analytical techniques and so demand the development of new tools for research. In the near future, the development of highly integrated microfluidic analytical platforms will enable the acquisition of unknown biological data. These microfluidic systems must allow cell culture under controlled microenvironment and high throughput analysis. For this purpose, the integration of a variable number of newly developed micro- and nano-technologies, which enable control of topography and surface chemistry, soluble factors, mechanical forces and cell-cell contacts, as well as technology for monitoring cell phenotype and genotype with high spatial and temporal resolution will be necessary. These multifunctional devices must be accompanied by appropriate data analysis and management of the expected large datasets generated. The knowledge gained with these platforms has the potential to improve predictive models of the behavior of cells, impacting directly in better therapies for disease treatment. In this review, we give an overview of the microtechnology toolbox available for the design of high throughput microfluidic platforms for cell analysis. We discuss current microtechnologies for cell microenvironment control, different methodologies to create large arrays of cellular systems and finally techniques for monitoring cells in microfluidic devices.E.A.-H. acknowledges funding from the Basque Government, Department of Education, for predoctoral fellowship 2016. M.G.-H. acknowledges funding from the University of the Basque Country UPV/EHU, PIF16/204 predoctoral fellowship "call for recruitment of research personnel in training". J.E.-E. acknowledges funding from the University of the Basque Country UPV/EHU, postdoctoral fellowship ESPPOC 16/65 "Call for recruitment and specialization of Doctor Researchers 2016". M.M.D.P. and L.B.-D., acknowledge funding support from University of the Basque Country UPV/EHU, UFI11/32, and from Gobierno Vasco under Grupos Consolidados with Grant No. IT998-16. F.B.-L. acknowledges funding support from the Ramon y Cajal Programme (Ministerio de Economia y Competitividad), Spain. F.B.-L. and L.B.-D. acknowledge funding support from the European Union's Seventh Framework Programme (FP7) for Research, Technological Development and Demonstration under Grant agreement No. 604241 as well as Gobierno Vasco, Dpto. Industria, Innovacion, Comercio y Turismo under ELKARTEK 2015 with Grant No. KK-2015/0000088

Novel Current-Mode Sensor Interfacing and Radio Blocks for Cell Culture Monitoring

Since 2004 Imperial College has been developing the world’s first application-specific instrumentation aiming at the on-line, in-situ, physiochemical monitoring of adult stem cell cultures. That effort is internationally known as the ‘Intelligent Stem Cell Culture Systems’ (ISCCS) project. The ISCCS platform is formed by the functional integration of biosensors, interfacing electronics and bioreactors. Contrary to the PCB-level ISCCS platform the work presented in this thesis relates to the realization of a miniaturized cell culture monitoring platform. Specifically, this thesis details the synthesis and fabrication of pivotal VLSI circuit blocks suitable for the construction of a miniaturized microelectronic cell monitoring platform. The thesis is composed of two main parts. The first part details the design and operation of a two-stage current-input currentoutput topology suitable for three-electrode amperometric sensor measurements. The first stage is a CMOS-dual rail-class AB-current conveyor providing a low impedancevirtual ground node for a current input. The second stage is a novel hyperbolic-sinebased externally-linear internally-non-linear current amplification stage. This stage bases its operation upon the compressive sinh−1 conversion of the interfaced current to an intermediate auxiliary voltage and the subsequent sinh expansion of the same voltage. The proposed novel topology has been simulated for current-gain values ranging from 10 to 1000 using the parameters of the commercially available 0.8μm AMS CMOS process. Measured results from a chip fabricated in the same technology are also reported. The proposed interfacing/amplification architecture consumes 0.88-95μW. The second part describes the design and practical evaluation of a 13.56MHz frequency shift keying (FSK) short-range (5cm) telemetry link suitable for the monitoring of incubated cultures. Prior to the design of the full FSK radio system, a pair of 13.56MHz antennae are characterized experimentally. The experimental S-parameter-value determination of the 13.56MHz wireless link is incorporated into the Cadence Design Framework allowing a high fidelity simulation of the reported FSK radio. The transmitter of the proposed system is a novel multi-tapped seven-stage ring-oscillator-based VCO whereas the core of the receiver is an appropriately modified phase locked loop (PLL). Simulated and measured results from a 0.8μm CMOS technology chip are reported

Roadmap on semiconductor-cell biointerfaces.

This roadmap outlines the role semiconductor-based materials play in understanding the complex biophysical dynamics at multiple length scales, as well as the design and implementation of next-generation electronic, optoelectronic, and mechanical devices for biointerfaces. The roadmap emphasizes the advantages of semiconductor building blocks in interfacing, monitoring, and manipulating the activity of biological components, and discusses the possibility of using active semiconductor-cell interfaces for discovering new signaling processes in the biological world

A modular multi electrode array system for electrogenic cell characterisation and cardiotoxicity applications

Multi electrode array (MEA) systems have evolved from custom-made experimental tools, exploited for neural research, into commercially available systems that are used throughout non-invasive electrophysiological study. MEA systems are used in conjunction with cells and tissues from a number of differing organisms (e.g. mice, monkeys, chickens, plants). The development of MEA systems has been incremental over the past 30 years due to constantly changing specific bioscientific requirements in research. As the application of MEA systems continues to diversify contemporary commercial systems are requiring increased levels of sophistication and greater throughput capabilities. [Continues.