3D-Printed electrochemical sensor-integrated transwell systems

Abstract This work presents a 3D-printed, modular, electrochemical sensor-integrated transwell system for monitoring cellular and molecular events in situ without sample extraction or microfluidics-assisted downstream omics. Simple additive manufacturing techniques such as 3D printing, shadow masking, and molding are used to fabricate this modular system, which is autoclavable, biocompatible, and designed to operate following standard operating protocols (SOPs) of cellular biology. Integral to the platform is a flexible porous membrane, which is used as a cell culture substrate similarly to a commercial transwell insert. Multimodal electrochemical sensors fabricated on the membrane allow direct access to cells and their products. A pair of gold electrodes on the top side of the membrane measures impedance over the course of cell attachment and growth, characterized by an exponential decrease (~160% at 10 Hz) due to an increase in the double layer capacitance from secreted extracellular matrix (ECM) proteins. Cyclic voltammetry (CV) sensor electrodes, fabricated on the bottom side of the membrane, enable sensing of molecular release at the site of cell culture without the need for downstream fluidics. Real-time detection of ferrocene dimethanol injection across the membrane showed a three order-of-magnitude higher signal at the membrane than in the bulk media after reaching equilibrium. This modular sensor-integrated transwell system allows unprecedented direct, real-time, and noninvasive access to physical and biochemical information, which cannot be obtained in a conventional transwell system.

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Highly sensitive real-time detection of intracellular oxidative stress and application in mycotoxin toxicity evaluation based on living single-cell electrochemical sensors

The Analyst ◽

10.1039/d0an02015j ◽

2021 ◽

Author(s):

Lu Gao ◽

Jiadi Sun ◽

Liping Wang ◽

Qigao Fan ◽

Gaowen Zhu ◽

...

Keyword(s):

Oxidative Stress ◽

Electrochemical Sensor ◽

Single Cell ◽

Real Time ◽

Electrochemical Sensors ◽

Living Cells ◽

Selective Detection ◽

Toxicity Evaluation ◽

Highly Sensitive ◽

Intracellular Oxidative Stress

Single-cell electrochemical sensor is used in the local selective detection of living cells because of its high spatial–temporal resolution and sensitivity, as well as its ability to obtain comprehensive cellular physiological states and processes.

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The Development of Electrochemical Hypergolic Vapor Monitoring Instrument

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.333-335.1578 ◽

2013 ◽

Vol 333-335 ◽

pp. 1578-1581

Author(s):

Ye Cao ◽

Guang You Zhang ◽

Li Wang

Keyword(s):

Environmental Pollution ◽

Electrochemical Sensor ◽

Real Time ◽

Electrochemical Sensors ◽

Monitoring Instrument

To prevent environmental pollution and leakage accident, a hypergolic vapor monitoring instrument based on electrochemistry is discussed in this paper. The electrochemical sensor is designed to detect hydrazine compounds of 10-6 level in real time .The monitoring instrument based on electrochemical sensors shows its advantage of hign specificity and fine stability .

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Detection of Candida albicans Using a Manufactured Electrochemical Sensor

Micromachines ◽

10.3390/mi12020166 ◽

2021 ◽

Vol 12 (2) ◽

pp. 166

Author(s):

Prakhar Dutta ◽

Yi-Jung Lu ◽

Han-Yu Hsieh ◽

Tyng-Yuh Lee ◽

Yi-Tzu Lee ◽

...

Keyword(s):

Cell Culture ◽

Cell Wall ◽

Candida Albicans ◽

Electrochemical Sensor ◽

Nosocomial Infections ◽

Electrochemical Sensors ◽

Real Situation ◽

Screen Procedure ◽

Glucose Meter ◽

Urine And Serum

Candida albicans is a commensal fungus that is responsible for a lot of nosocomial infections in immunocompromised people. Cell culture is currently the predominant method for diagnosing candidiasis, but it is time consuming. In this study, we developed a rapid screen procedure by devising a method for detecting C. albicans with the use of electrochemical sensors. Through this experiment, we propose a method for the detection of C. albicans in the system through the use of personal glucose meters. The hemicellulase was used to break down the cell wall of C. albicans to glucose and oligo, which can be detected by a glucose meter. The spiked samples were prepared suspending C. albicans in urine and serum, demonstrating the feasibility of the developed method in a real situation.

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Synthesizing Electrodes Into Electrochemical Sensor Systems

Frontiers in Chemistry ◽

10.3389/fchem.2021.641674 ◽

2021 ◽

Vol 9 ◽

Author(s):

Yulia G. Mourzina ◽

Yuri E. Ermolenko ◽

Andreas Offenhäusser

Keyword(s):

Hydrogen Peroxide ◽

Electrochemical Sensor ◽

Real Time ◽

Electrochemical Sensors ◽

Electrochemical Determination ◽

Sensor System ◽

Counter Electrodes ◽

Sensor Material ◽

Multiple Analytes

Electrochemical sensors that can determine single/multiple analytes remain a key challenge in miniaturized analytical systems and devices. In this study, we present in situ synthesis and modification of gold nanodendrite electrodes to create an electrochemical system for the analysis of hydrogen peroxide. The sensor system consisted of the reference and counter electrodes as well as the working electrode. Electrochemical reduction of graphene oxide, ErGO, on the thin-film gold and gold nanodendrite working electrodes was used to achieve an efficient sensor interface for the adsorption of a biomimetic electrocatalytic sensor material, Mn(III) meso-tetra(N-methyl-4-pyridyl) porphyrin complex, with as high as 10–10 mol cm−2 surface coverage. The sensor system demonstrated a detection limit of 0.3 µM H2O2 in the presence of oxygen. Electrochemical determination of hydrogen peroxide in plant material in the concentration range from 0.09 to 0.4 µmol (gFW)−1 using the electrochemical sensor system was shown as well as in vivo real-time monitoring of the hydrogen peroxide dynamics as a sign of abiotic stress (intense sunlight). Results of the electrochemical determination were in good agreement with the results of biochemical analysis with the spectrophotometric detection. We anticipate that this method can be extended for the synthesis and integration of multisensor arrays in analytical microsystems and devices for the quantification and real-time in vivo monitoring of other analytes and biomarkers.

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Automated cell counting of astrocytes on patterned substrates containing aliphatic and charged properties

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010014124x ◽

1995 ◽

Vol 53 ◽

pp. 974-975

Author(s):

W. Shain ◽

H. Ancin ◽

H.C. Craighead ◽

M. Isaacson ◽

L. Kam ◽

...

Keyword(s):

Cell Culture ◽

Cell Attachment ◽

Culture Method ◽

Cell Counting ◽

Data Sets ◽

Nuclear Staining ◽

Double Positive ◽

A Cell ◽

Wafer Test ◽

Cell Densities

Neural protheses have potential to restore nervous system functions lost by trauma or disease. Nanofabrication extends this approach to implants for stimulating and recording from single or small groups of neurons in the spinal cord and brain; however, tissue compatibility is a major limitation to their practical application. We are using a cell culture method for quantitatively measuring cell attachment to surfaces designed for nanofabricated neural prostheses.Silicon wafer test surfaces composed of 50-μm bars separated by aliphatic regions were fabricated using methods similar to a procedure described by Kleinfeld et al. Test surfaces contained either a single or double positive charge/residue. Cyanine dyes (diIC18(3)) stained the background and cell membranes (Fig 1); however, identification of individual cells at higher densities was difficult (Fig 2). Nuclear staining with acriflavine allowed discrimination of individual cells and permitted automated counting of nuclei using 3-D data sets from the confocal microscope (Fig 3). For cell attachment assays, LRM5 5 astroglial cells and astrocytes in primary cell culture were plated at increasing cell densities on test substrates, incubated for 24 hr, fixed, stained, mounted on coverslips, and imaged with a 10x objective.

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A 3D-printed Microfluidic System for Automated and Near Real-time Quantitation of Biofilm-induced indole

10.26434/chemrxiv.11372217 ◽

2019 ◽

Author(s):

Giraso Kabandana ◽

Curtis G. Jones ◽

Sahra Khan Sharifi ◽

Chengpeng Chen

Keyword(s):

Real Time ◽

Release Kinetics ◽

Microfluidic System ◽

3D Printed

We developed a novel microfluidic system that enables automated and near real-time quantitation of indole release kinetics from biofilms.

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Real-time monitoring of liver fibrosis through embedded sensors in a microphysiological system

Nano Convergence ◽

10.1186/s40580-021-00253-y ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Hafiz Muhammad Umer Farooqi ◽

Bohye Kang ◽

Muhammad Asad Ullah Khalid ◽

Abdul Rahim Chethikkattuveli Salih ◽

Kinam Hyun ◽

...

Keyword(s):

Cell Culture ◽

Liver Fibrosis ◽

Real Time ◽

Hepatic Fibrosis ◽

Transforming Growth Factor ◽

Cell Monolayer ◽

Embedded Sensors ◽

Matrix Deposition ◽

Tgf Β1

AbstractHepatic fibrosis is a foreshadowing of future adverse events like liver cirrhosis, liver failure, and cancer. Hepatic stellate cell activation is the main event of liver fibrosis, which results in excessive extracellular matrix deposition and hepatic parenchyma's disintegration. Several biochemical and molecular assays have been introduced for in vitro study of the hepatic fibrosis progression. However, they do not forecast real-time events happening to the in vitro models. Trans-epithelial electrical resistance (TEER) is used in cell culture science to measure cell monolayer barrier integrity. Herein, we explored TEER measurement's utility for monitoring fibrosis development in a dynamic cell culture microphysiological system. Immortal HepG2 cells and fibroblasts were co-cultured, and transforming growth factor β1 (TGF-β1) was used as a fibrosis stimulus to create a liver fibrosis-on-chip model. A glass chip-based embedded TEER and reactive oxygen species (ROS) sensors were employed to gauge the effect of TGF-β1 within the microphysiological system, which promotes a positive feedback response in fibrosis development. Furthermore, albumin, Urea, CYP450 measurements, and immunofluorescent microscopy were performed to correlate the following data with embedded sensors responses. We found that chip embedded electrochemical sensors could be used as a potential substitute for conventional end-point assays for studying fibrosis in microphysiological systems.

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Real-time imaging of cellular forces using optical interference

Nature Communications ◽

10.1038/s41467-021-23734-4 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Andrew T. Meek ◽

Nils M. Kronenberg ◽

Andrew Morton ◽

Philipp Liehm ◽

Jan Murawski ◽

...

Keyword(s):

Cell Culture ◽

Real Time ◽

High Throughput ◽

Mechanical Activity ◽

Dynamic Processes ◽

Imaging Method ◽

Neonatal Cardiomyocytes ◽

A Cell ◽

Cellular Forces ◽

Time Acquisition

AbstractImportant dynamic processes in mechanobiology remain elusive due to a lack of tools to image the small cellular forces at play with sufficient speed and throughput. Here, we introduce a fast, interference-based force imaging method that uses the illumination of an elastic deformable microcavity with two rapidly alternating wavelengths to map forces. We show real-time acquisition and processing of data, obtain images of mechanical activity while scanning across a cell culture, and investigate sub-second fluctuations of the piconewton forces exerted by macrophage podosomes. We also demonstrate force imaging of beating neonatal cardiomyocytes at 100 fps which reveals mechanical aspects of spontaneous oscillatory contraction waves in between the main contraction cycles. These examples illustrate the wider potential of our technique for monitoring cellular forces with high throughput and excellent temporal resolution.

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An Improved Transwell Design for Microelectrode Ion-Flux Measurements

Micromachines ◽

10.3390/mi12030273 ◽

2021 ◽

Vol 12 (3) ◽

pp. 273

Author(s):

Boris Buchroithner ◽

Pavel Spurný ◽

Sandra Mayr ◽

Johannes Heitz ◽

Dmitry Sivun ◽

...

Keyword(s):

Umbilical Vein ◽

Cell Monolayer ◽

Three Dimensional ◽

Cellular Membrane ◽

Ion Flux ◽

Direct Access ◽

Cell Contact ◽

Culture Dish ◽

Tissue Culture Dish ◽

Transwell System

The microelectrode ion flux estimation (MIFE) is a powerful, non-invasive electrophysiological method for cellular membrane transport studies. Usually, the MIFE measurements are performed in a tissue culture dish or directly with tissues (roots, parts of the plants, and cell tissues). Here, we present a transwell system that allows for MIFE measurements on a cell monolayer. We introduce a measurement window in the transwell insert membrane, which provides direct access for the cells to the media in the upper and lower compartment of the transwell system and allows direct cell-to-cell contact coculture. Three-dimensional multiphoton lithography (MPL) was used to construct a 3D grid structure for cell support in the measurement window. The optimal polymer grid constant was found for implementation in transwell MIFE measurements. We showed that human umbilical vein endothelial cells (HUVECs) efficiently grow and maintain their physiological response on top of the polymer structures.

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