Project description:Microfluidic devices provide a low-input and efficient platform for single-cell RNA-seq (scRNA-Seq). Here we present microfluidic diffusion-based RNA-seq (MID-RNA-seq) for conducting scRNA-seq with a diffusion-based reagent swapping scheme. This device incorporates cell trapping, lysis, reverse transcription and PCR amplification all in one microfluidic chamber. MID-RNA-Seq provides high data quality that is comparable to existing scRNA-seq methods while implementing a simple device design that permits multiplexing. The robustness and scalability of MID-RNA-Seq device will be important for transcriptomic studies of scarce cell samples.
Project description:Single-cell whole-transcriptome analysis is a powerful tool for quantifying gene expression heterogeneity in populations of cells. Many techniques have, thus, been recently developed to perform transcriptome sequencing (RNA-Seq) on individual cells. To probe subtle biological variation between samples with limiting amounts of RNA, more precise and sensitive methods are still required. We adapted a previously developed strategy for single-cell RNA-Seq that has shown promise for superior sensitivity and implemented the chemistry in a microfluidic platform for single-cell whole transcriptome analysis. In this approach, single cells are captured and lysed in a microfluidic device, where mRNAs with poly(A) tails are reverse-transcribed into cDNA. Double-stranded cDNA is then collected and sequenced using a next-generation sequencing platform. We prepared 94 libraries consisting of single mouse embryonic cells and technical replicates of extracted RNA and thoroughly characterized the performance of this technology. Microfluidic implementation increased mRNA detection sensitivity as well as improved measurement precision compared with tube-based protocols. With 0.2M reads per cell, we were able to reconstruct a majority of the bulk transcriptome with 10 single cells. We also quantified variation between and within different types of mouse embryonic cells and found that enhanced measurement precision, detection sensitivity, and experimental throughput aided the distinction between biological variability and technical noise. With this work, we validated the advantages of an early approach to single-cell RNA-Seq and showed that the benefits of combining microfluidic technology with high-throughput sequencing will be valuable for large-scale efforts in single-cell transcriptome analysis. We investigated gene expression in mouse embryonic cells using microfluidic-facilitated RNA-Seq to analyze 56 single mouse ES cell (mESC) transcriptomes and 6 single mouse embryonic fibroblast (MEF) transcriptomes. To quantitatively evaluate the sensitivity and precision of our technique, we also sequenced 23 libraries from extracted mESC RNA, representing three sets of technical replicates with varying starting amounts of material.
Project description:Immunoassays have been used for decades in clinical laboratories to quantify proteins in serum/plasma samples. However, different limitations hinder their use in some cases. Mass spectrometry (MS)-based proteomics analysis has recently appeared as a promising option to assess panels of protein biomarkers and provide protein profiles useful for health state monitoring. Nevertheless, translation of MS-based proteomics into the clinics is still hampered by the complexity, the substantial time and human workforce necessary for sample preparation. The processing of plasma matrix is especially tricky as it contains more than 3000 proteins spanning in an extreme dynamic range (10e10) of concentrations. To address this pre-analytical challenge, we have conceived a microfluidic device (PepS) to automate and accelerate blood sample preparation for bottom-up MS-based proteomic analysis. The microfluidic cartridge is operated through a dedicated compact instrument providing fully automated fluid processing and thermal control. In less than 2 hours, PepS device enables whole blood collection at the bedside, plasma separation and calibration, depletion of albumin, protein digestion with trypsin and stabilization of tryptic peptides on solid phase extraction sorbent. The performance of PepS device was assessed using discovery proteomics and targeted proteomics on a panel of three protein biomarkers routinely assayed in clinical laboratories. This innovative microfluidic device and associated instrumentation is expected to streamline and simplify clinical proteomic studies.
Project description:We established a platform for the brain organoid culture by using human decellularized brain extracellular matrix (BEM) and a microfluidic device. This engineering concept of reconstituting brain-mimetic microenvironments facilitates development of a reliable culture platform for brain organoids, enabling effective modeling and drug development.
Project description:Single-cell whole-transcriptome analysis is a powerful tool for quantifying gene expression heterogeneity in populations of cells. Many techniques have, thus, been recently developed to perform transcriptome sequencing (RNA-Seq) on individual cells. To probe subtle biological variation between samples with limiting amounts of RNA, more precise and sensitive methods are still required. We adapted a previously developed strategy for single-cell RNA-Seq that has shown promise for superior sensitivity and implemented the chemistry in a microfluidic platform for single-cell whole transcriptome analysis. In this approach, single cells are captured and lysed in a microfluidic device, where mRNAs with poly(A) tails are reverse-transcribed into cDNA. Double-stranded cDNA is then collected and sequenced using a next-generation sequencing platform. We prepared 94 libraries consisting of single mouse embryonic cells and technical replicates of extracted RNA and thoroughly characterized the performance of this technology. Microfluidic implementation increased mRNA detection sensitivity as well as improved measurement precision compared with tube-based protocols. With 0.2M reads per cell, we were able to reconstruct a majority of the bulk transcriptome with 10 single cells. We also quantified variation between and within different types of mouse embryonic cells and found that enhanced measurement precision, detection sensitivity, and experimental throughput aided the distinction between biological variability and technical noise. With this work, we validated the advantages of an early approach to single-cell RNA-Seq and showed that the benefits of combining microfluidic technology with high-throughput sequencing will be valuable for large-scale efforts in single-cell transcriptome analysis.
Project description:We developed the microfluidic-oscillatory-washing-based ChIP-Seq (MOWChIP-Seq) protocol. We achieved genome-wide mapping of histone modifications (H3K4me3 and H3K27ac) with as few as 100 cells. Moreover, the automated microfluidic platform dramatically reduced assay time and has a potential for future scale-up.
Project description:Hydrodynamic-based microfluidic platforms enable single-cell arraying and analysis over time. Despite the advantages of established microfluidic systems, long term analysis and proliferation of cells selected in such devices require off-chip recovery of cells as well as an investigation of on-chip analysis on cell phenotype; requirements still largely unmet. Here, we introduce a device for single-cell isolation, selective retrieval and off-chip recovery. To this end, singularly addressable three-dimensional electrodes are embedded within a microfluidic channel, allowing, through application of a negative dielectrophoretic (DEP) force, the selective release of single cells from their trapping site. Selective capture and release is carried out in standard culture medium and cells can be subsequently single cell mitigated towards a recovery well using hybrid SU-8/PDMS pneumatic valves. Importantly, transcriptional analysis of recovered cells revealed only marginal alteration of the molecular profile upon DEP application, underscored by equivocal minor transcriptional changes induced upon injection into the microfluidics device. Therefore, the established microfluidic system combining targeted DEP manipulation with down-stream hydrodynamic coordination of single cells, provides the means to handle and manipulate individual cells within one device.
Project description:Investigation in bacterial transcriptomics is widely used to investigate gene regulation, bacterial susceptibility to antibiotics, host-pathogen interactions, and pathogenesis. Transcriptomics is crucially dependent on suitable methods to isolate and detect bacterial RNA. Microfluidic approaches offer ways of creating integrated point-of-care systems, analysing a sample from preparation, RNA isolation through to detection. Critical for on-chip diagnostics to deliver on their promise is that mRNA expression is not altered through the use microfluidic sample processing. Here, we investigate the impact on the use of a microfluidic sample processing system based on hydrodynamic separation upon RNA expression of bacteria isolated from blood to prove its suitability for further microfluidic test development. A 10 array study using total RNA recovered from bacteria isolated using the microfluidic device and total RNA recovered from bacteria that were not separated using the device were compared. Arrays were performed in 5 biological replicates from each condition
Project description:Tissues are composed of highly heterogeneous mixtures of cell subtypes, and this diversity is increasingly being characterized using high-throughput single cell analysis methods. However, these efforts are hindered by the fact that tissues must first be dissociated into single cell suspensions that are viable and still accurately represent phenotypes from the original tissue. Current methods for breaking down tissues are inefficient, labor-intensive, subject to high variability, and potentially biased towards cell subtypes that are easier to release. Here, we present a microfluidic platform consisting of three different tissue processing technologies that can perform the complete tissue to single cell workflow, including digestion, disaggregation, and filtration. First, we developed a new microfluidic digestion device that can be loaded with minced tissue specimens quickly and easily, and then use the combination of proteolytic enzyme activity and fluid shear forces to accelerate tissue breakdown. Next, we integrated dissociation and filter technologies into a single device, which enhanced single cell numbers and fully prepared the sample for single cell analysis. The final multi-device platform was then evaluated using a diverse array of tissue types that exhibited a wide range of properties. For murine kidney and mammary tumor, we found that microfluidic processing produced 2.5-fold more single, viable cells. Single cell RNA sequencing (scRNA-seq) further revealed that device processing enriched for endothelial cells, fibroblasts, and basal epithelium, and did not increase stress responses. For murine liver and heart, which are softer tissues containing fragile cell types, processing time could be reduced to 15 min, and even as short as 1 min. We also demonstrated that periodic recovery at defined time intervals produced substantially more hepatocytes and cardiomyocytes than continuous operation, most likely by preventing damage to fragile cell types. In future work, we will seek to integrate additional operations such as upstream tissue preparation and downstream microfluidic cell sorting and detection to create powerful point-of-care single cell diagnostic platforms.