Monitoring induced gene expression of single cells in a multilayer microchip

Assessment of metabolism-dependent drug efficacy and toxicity on a multilayer organs-on-a-chip

This work presents a new and multifunctional organs-on-a-chip device that allows for the characterization of the multi-step metabolism processes of pro-drug CAP in liver cells and its resultant efficacy in multiple target cells simultaneously and quantitatively.

Analysis of metabolites in single cells-what is the best micro-platform?

This review covers new innovations and developments in the field of single-cell level analysis of metabolites, involving the role of microfluidic and microarray platforms to manipulate and handle the cells prior their detection. Microfluidic and microarray platforms have shown great promise. The latest developments demonstrate their potential to identify a particular cell or even an ensemble of cells (sharing a common property or phenotype) that co-exist in a much larger cell population. The reason for this is the capability of these platforms to perform several complex analytical processes, such as: cleanup, sorting, derivatization, separation, and detection, with great robustness, speed, and reduced sample/reagent consumption. Here, we present several examples that illustrate the rapid strides that have been made for the routine analysis of metabolites by coupling different microfluidics and microarrays devices to a wide range of analytical detectors (e.g. fluorescent microscopy, electrochemical, and mass spectrometry). Herein, we also present selected examples detailing the use of microfluidics and microarrays in the visualization of the natural occurring cell-to-cell heterogeneity in isogenic populations, in particular during the response to external cues. The possibility to accurate monitor the cell-to-cell heterogeneity based on different levels of key metabolites is of clinical relevance, since cell-to-cell heterogeneity can influence, for example, the outcome of a drug treatment.

High-throughput microfluidic platform for adherent single cells non-viral gene delivery

Microfluidic platform for the high-throughput screening of gene delivery vectors and optimization of the transfection protocols at a single cell level.

On-chip investigation of cell-drug interactions

Investigation of cell-drug interaction is of great importance in drug discovery but continues to pose significant challenges to develop robust, fast and high-throughput methods for pharmacologically profiling of potential drugs. Recently, cell chips have emerged as a promising technology for drug discovery/delivery, and their miniaturization and flow-through operation significantly reduce sample consumption while dramatically improving the throughput, reliability, resolution and sensitivity. Herein we review various types of miniaturized cell chips used in investigation of cell-drug interactions. The design and fabrication of cell chips including material selection, surface modification, cell trapping/patterning, concentration gradient generation and mimicking of in vivo environment are presented. Recent advances of on-chip investigations of cell-drug interactions, in particular the high-throughput screening, cell sorting, cytotoxicity testing, drug resistance analysis and pharmacological profiling are examined and discussed. It is expected that this survey can provide thoughtful basics and important applications of on-chip investigations of cell-drug interactions, thus greatly promoting research and development interests in this area.

Dielectrophoretic cell capture on polyester membranes

A new system for dielectrophoretic cell capture on permeable polyester membranes is presented. Conventional photolithographic techniques were used to fabricate gold microelectrodes on a polyester membrane. The characterization of the microelectrodes showed that there were no differences regarding roughness, permeability, and hydrophilicity of the membrane before and after processing. Finally, dielectrophoretic cell capture and viability in a microfluidic device was demonstrated on the patterned membrane. These membranes could ultimately be combined with multilayer microfluidic devices to form a powerful tool for studies of cell-cell interactions in coculture, whereby spatial separation of different cell types and/or microenvironments are required.

A microchamber array for single cell isolation and analysis of intracellular biomolecules

We present a microfluidic device that enables the determination of intracellular biomolecules in multiple single cells. The cells are individually trapped and isolated in a microchamber array. Since the microchambers can be opened and closed reversibly, the cells can be exposed to different solutions sequentially, e.g. for incubation, washing steps, labelling and finally, for lysis. The tightly sealed microchambers enable the retention and analysis of cell lysate derived from single cells. The performance of the device is demonstrated by monitoring the levels of the cofactors NADPH and NADH both in healthy mammalian cells and in cells exposed to oxidative stress. The platform was also used to determine the toxic impact of the alkaloid camptothecin on the intracellular enzyme glucose-6-phosphate dehydrogenase levels. In general, the device is applicable for the analysis of cell auto-stimulation and the detection of intracellular metabolite concentration or expression levels of proteins.