An easy-to-operate method for single-cell isolation and retrieval using a microfluidic static droplet array

Microfluidics Coupled Mass Spectrometry for Single Cell Multi-Omics

Population-level analysis masks significant heterogeneity between individual cells, making it difficult to accurately reflect the true intricacies of life activities. Microfluidics is a technique that can manipulate individual cells effectively and is commonly coupled with a variety of analytical methods for single-cell analysis. Single-cell omics provides abundant molecular information at the single-cell level, fundamentally revealing differences in cell types and biological states among cell individuals, leading to a deeper understanding of cellular phenotypes and life activities. Herein, this work summarizes the microfluidic chips designed for single-cell isolation, manipulation, trapping, screening, and sorting, including droplet microfluidic chips, microwell arrays, hydrodynamic microfluidic chips, and microchips with microvalves. This work further reviews the studies on single-cell proteomics, metabolomics, lipidomics, and multi-omics based on microfluidics and mass spectrometry. Finally, the challenges and future application of single-cell multi-omics are discussed.

Electrochemical sensor for simultaneous determination of antiviral favipiravir drug, paracetamol and vitamin C based on host-guest inclusion complex of β-CD/CNTs nanocomposite

Favipiravir (FVI) is extensively used as an effective medication against several diverse infectious RNA viruses. It is widely administered as an anti-influenza drug. Combination therapy formed from FVI, paracetamol (PAR) and vitamin C (VC) is needed for treating patients diseased by RNA viruses. Thus, an efficient electrochemical sensor is developed for detecting FVI in human serum samples. The sensor is fabricated by casting a thin layer of carbon nanotubes (CNTs) over a glassy carbon (GC) electrode surface followed by electrodeposition of another layer of β-cyclodextrin (β-CD). Under optimized conditions, the sensor shows excellent catalytic effect for FVI, PAR and VC oxidation in the concentration ranges (0.08 µM → 80 µM), (0.08 µM → 50 µM) and (0.8 µM → 80 µM) with low detection limits of 0.011 μM, 0.042 μM and 0.21 μM, respectively. The combined effect of host-guest interaction ability of β-CD for the drugs, and a large conductive surface area of CNTs improves the sensing performance of the electrode. The sensor exhibits stable response over 4 weeks, good reproducibility, and insignificant interference from common species present in serum samples. The reliability of using the sensor in serum samples shows good recovery of FVI, PAR and VC.

On-chip dielectrophoretic device for cancer cell manipulation: A numerical and artificial neural network study

Breast cancer, as one of the most frequent types of cancer in women, imposes large financial and human losses annually. MCF-7, a well-known cell line isolated from the breast tissue of cancer patients, is usually used in breast cancer research. Microfluidics is a newly established technique that provides many benefits, such as sample volume reduction, high-resolution operations, and multiple parallel analyses for various cell studies. This numerical study presents a novel microfluidic chip for the separation of MCF-7 cells from other blood cells, considering the effect of dielectrophoretic force. An artificial neural network, a novel tool for pattern recognition and data prediction, is implemented in this research. To prevent hyperthermia in cells, the temperature should not exceed 35 °C. In the first part, the effect of flow rate and applied voltage on the separation time, focusing efficiency, and maximum temperature of the field is investigated. The results denote that the separation time is affected by both the input parameters inversely, whereas the two remaining parameters increase with the input voltage and decrease with the sheath flow rate. A maximum focusing efficiency of 81% is achieved with a purity of 100% for a flow rate of 0.2 μ L / min and a voltage of 3.1 V . In the second part, an artificial neural network model is established to predict the maximum temperature inside the separation microchannel with a relative error of less than 3% for a wide range of input parameters. Therefore, the suggested label-free lab-on-a-chip device separates the target cells with high-throughput and low voltages.

An ultra-compact acoustofluidic device based on the narrow-path travelling surface acoustic wave (np-TSAW) for label-free isolation of living circulating tumor cells

Obtaining highly purified intact living cells from complex environments has been a challenge, such as the isolation of circulating tumor cells (CTCs) from blood. In this work, we demonstrated an acoustic-based ultra-compact device for cell sorting, with a chip size of less than 2 × 1.5 cm². This single actuator device allows non-invasive and label-free isolation of living cells, offering greater flexibility and applicability. The device performance was optimized with different-sized polystyrene (PS) particles and blood cells spiked with cancer cells. Using the narrow-path travelling surface acoustic wave (np-TSAW), precise isolation of 10 μm particles from a complex mixture of particles (5, 10, 20 μm) and separation of 8 μm and 10 μm particles was achieved. The purified collection of 10 μm particles with high separation efficiency (98.75%) and high purity (98.1%) was achieved by optimizing the input voltage. Further, we investigated the isolation and purification of CTCs (MCF-7, human breast cancer cells) from blood cells with isolation efficiency exceeding 98% and purity reaching 93%. Viabilities of the CTCs harvested from target-outlet were all higher than 97% after culturing for 24, 48, and 72 h, showing good proliferation ability. This novel ultra-miniaturized microfluidic chip demonstrates the ability to sorting cells with high-purity and label-free, providing an attractive miniaturized system alternative to traditional sorting methods.

Static droplet array for the synthesis of nonspherical microparticles

We reported a manually operated static droplet array (SDA)-based device for the synthesis of nonspherical microparticles with different shapes. The improved SDA structure and reversible bonding between poly(dimethylsiloxane) (PDMS) were used in the device for the large-scale synthesis and rapid extraction of nonspherical microparticles. To understand the device physics, the effects of flow rate, SDA well size, and shape on droplet generation performances were explored. The results indicated that droplet generation in SDA structures was insensitive to the flow rate, and monodisperse droplets were generated by the SDA-based device through manually pushing the syringe. Finally, we integrated four kinds of SDA structures in one device and successfully realized the synthesis and extraction of nonspherical microparticles with different shapes and materials. Our SDA-based device offers numerous advantages, such as simple manual operation, low equipment cost, controllable microparticle shapes and sizes, and large-scale production. Thus, it holds the potential to be used as a flexible tool for the production of nonspherical microparticles.

Rapid metabolomic screening of cancer cells via high-throughput static droplet microfluidics

Effective isolation and in-depth analysis of Circulating Tumour Cells (CTCs) are greatly needed in diagnosis, prognosis and monitoring of the therapeutic response of cancer patients but have not been completely fulfilled by conventional approaches. The rarity of CTCs and the lack of reliable biomarkers to distinguish them from peripheral blood cells have remained outstanding challenges for their clinical implementation. Herein, we developed a high throughput Static Droplet Microfluidic (SDM) device with 38,400 chambers, capable of isolating and classifying the number of metabolically active CTCs in peripheral blood at single-cell resolution. Owing to the miniaturisation and compartmentalisation capability of our device, we first demonstrated the ability to precisely measure the lactate production of different types of cancer cells inside 125 pL droplets at single-cell resolution. Furthermore, we compared the metabolomic activity of leukocytes from healthy donors to cancer cells and showed the ability to differentiate them. To further prove the clinical relevance, we spiked cancer cell lines in human healthy blood and showed the possibility to detect the cancer cells from leukocytes. Lastly, we tested the workflow on 8 preclinical mammary mouse models including syngeneic 67NR (non-metastatic) and 4T1.2 (metastatic) models with Triple-Negative Breast Cancer (TNBC) as well as transgenic mouses (12-week-old MMTV-PyMT). The results have shown the ability to precisely distinguish metabolically active CTCs from the blood using the proposed SDM device. The workflow is simple and robust which can eliminate the need for specialised equipment and expertise required for single-cell analysis of CTCs and facilitate on-site metabolic screening of cancer cells.

A Microfluidic Approach for Enrichment and Single-Cell Characterization of Circulating Tumor Cells from Peripheral Blood

The emergence of enabling technologies for the analysis of circulating tumor cells has been shedding new lights into cancer management in the recent years. However, majority of the technologies developed suffer from excessive cost, time-consuming workflows, and reliance on specialized equipment and operators. Herein, we propose a simple workflow for the isolation and characterization of single circulating tumor cells using microfluidic devices. The entire process can be operated by a laboratory technician without relying on any microfluidic expertise and can be completed within few hours of sample collection.

Computational fluid dynamics simulation study of hypersaline water desalination via membrane distillation: Effect of membrane characteristics and operational parameters

In this study, a comprehensive model was developed using Computational Fluid Dynamics (CFD), and the behaviour of a direct contact membrane distillation (DCMD) system was investigated at hypersaline feedwater conditions. The effects of various operating parameters including feed and permeate velocities, temperatures and salinities, as well as different membrane characteristics like thickness, porosity, and thermal conductivity were studied. The developed simulation model was also validated using experimental data. The results showed that the membrane conductivity and thickness had a significant impact on the DCMD performance, and the optimum operational condition was necessary to be determined. The results showed that increasing the feedwater salinity from 50 to 200 g/l decreased the membrane flux by up to 33%, while a four times decrease in thermal conductivity of the membrane could lead to an increase in the membrane flux from 11.2 to 32.4 l/m²·h (LMH). In addition, the optimal membrane thickness was found to increase with salinity, reaching >120 μm for treatment of 22 wt% NaCl feedwater solution. However, the flux declined from >32 LMH to <13 LMH upon the increase in feedwater salinity (up to 22 wt% NaCl solution). It is also shown that a thinner membrane performed better for desalination of low salinity feedwater, while the thicker one produces higher separation performance and thermal efficiency for hypersaline brine desalination.

Amiri H, Mas-hafi S, Banerjee B, Vesey G, Miansari M, Ebrahimi Warkiani M. Rapid and Continuous Cryopreservation of Stem Cells with a 3D Micromixer

Cryopreservation is the final step of stem cell production before the cryostorage of the product. Conventional methods of adding cryoprotecting agents (CPA) into the cells can be manual or automated with robotic arms. However, challenging issues with these methods at industrial-scale production are the insufficient mixing of cells and CPA, leading to damage of cells, discontinuous feeding, the batch-to-batch difference in products, and, occasionally, cross-contamination. Therefore, the current study proposes an alternative way to overcome the abovementioned challenges; a highly efficient micromixer for low-cost, continuous, labour-free, and automated mixing of stem cells with CPA solutions. Our results show that our micromixer provides a more homogenous mixing of cells and CPA compared to the manual mixing method, while the cell properties, including surface markers, differentiation potential, proliferation, morphology, and therapeutic potential, are well preserved.

A modular 3D printed microfluidic system: a potential solution for continuous cell harvesting in large-scale bioprocessing

Microfluidic devices have shown promising applications in the bioprocessing industry. However, the lack of modularity and high cost of testing and error limit their implementation in the industry. Advances in 3D printing technologies have facilitated the conversion of microfluidic devices from research output to applicable industrial systems. Here, for the first time, we presented a 3D printed modular microfluidic system consisting of two micromixers, one spiral microfluidic separator, and one microfluidic concentrator. We showed that this system can detach and separate mesenchymal stem cells (MSCs) from microcarriers (MCs) in a short time while maintaining the cell's viability and functionality. The system can be multiplexed and scaled up to process large volumes of the industry. Importantly, this system is a closed system with no human intervention and is promising for current good manufacturing practices.

The Role of Circulating Biomarkers in Lung Cancer

Lung cancer is the leading cause of cancer morbidity and mortality worldwide and early diagnosis is crucial for the management and treatment of this disease. Non-invasive means of determining tumour information is an appealing diagnostic approach for lung cancers as often accessing and removing tumour tissue can be a limiting factor. In recent years, liquid biopsies have been developed to explore potential circulating tumour biomarkers which are considered reliable surrogates for understanding tumour biology in a non-invasive manner. Most common components assessed in liquid biopsy include circulating tumour cells (CTCs), cell-free DNA (cfDNA), circulating tumour DNA (ctDNA), microRNA and exosomes. This review explores the clinical use of circulating tumour biomarkers found in liquid biopsy for screening, early diagnosis and prognostication of lung cancer patients.