Search Results (513)

Microfluidic platforms offer a powerful approach for ultimately replicating vascularization in vitro, enabling precise microscale control and manipulation of physical parameters. Despite these advances, the real-time ability to monitor and quantify mechanical forces—particularly pressure—within microfluidic environments remains constrained by limitations in cost and compatibility across diverse device architectures. Our work presents an advanced experimental module for quantifying pressure within a vascularizing microfluidic platform. Equipped with an integrated Arduino microcontroller and image monitoring, the system facilitates real-time remote monitoring to access temporal pressure and flow dynamics within the device. This setup provides actionable insights into the hemodynamic parameters driving vascularization in vitro. In-line pressure sensors, interfaced through I2C communication, are employed to precisely record inlet and outlet pressures during critical stages of microvasculature tubulogenesis. Flow measurements are obtained by analyzing changes in reservoir volume over time (dV/dt), correlated with the change in pressure over time (dP/dt). This quantitative assessment of various pressure conditions in a microfluidic platform offers insights into their impact on microvasculature perfusion kinetics. Data acquisition can help inform and finetune functional vessel network formation and potentially enhance the durability, stability, and reproducibility of engineered in vitro platforms for organoid vascularization in regenerative medicine. Full article

Electroporation-mediated gene delivery is a cornerstone of synthetic biology, offering several advantages over other methods: higher efficiencies, broader applicability, and simpler sample preparation. Yet, electroporation protocols are often challenging to integrate into highly multiplexed workflows, owing to limitations in their scalability and tunability. These challenges ultimately increase the time and cost per transformation. As a result, rapidly screening genetic libraries, exploring combinatorial designs, or optimizing electroporation parameters requires extensive iterations, consuming large quantities of expensive custom-made DNA and cell lines or primary cells. To address these limitations, we have developed a High-Throughput Microfluidic Electroporation (HTME) platform that includes a 384-well electroporation plate (E-Plate) and control electronics capable of rapidly electroporating all wells in under a minute with individual control of each well. Fabricated using scalable and cost-effective printed-circuit-board (PCB) technology, the E-Plate significantly reduces consumable costs and reagent consumption by operating on nano to microliter volumes. Furthermore, individually addressable wells facilitate rapid exploration of large sets of experimental conditions to optimize electroporation for different cell types and plasmid concentrations/types. Use of the standard 384-well footprint makes the platform easily integrable into automated workflows, thereby enabling end-to-end automation. We demonstrate transformation of E. coli with pUC19 to validate the HTME’s core functionality, achieving at least a single colony forming unit in more than 99% of wells and confirming the platform’s ability to rapidly perform hundreds of electroporations with customizable conditions. This work highlights the HTME’s potential to significantly accelerate synthetic biology Design-Build-Test-Learn (DBTL) cycles by mitigating the transformation/transfection bottleneck. Full article

Carbonation–calcination looping using CaO-based natural sorbents such as limestone is a promising technology for the capture of CO₂ from fossil fuel-based power plants. In this study, the CO₂ capture capacities of Buipe, Oterpkolu, and Nauli limestones from quarries in Ghana were measured in a laboratory-scale micro-fluidized bed reactor through multiple carbonation–calcination cycles. The changes in CO₂ capture capacity and conversion with the number of cycles mostly correlated with the changes in the physico-chemical properties: Capture capacity dropped from >60% to <15% after 15 cycles and the surface area dropped to below 5 m² g⁻¹ from as much as 20 m² g⁻¹ (for the Oterkpolu). The pore volume of the Nauli limestone was essentially invariant with the number of cycles while it increased for the Buipe limestone, and initially increased and then dropped for the Oterpkolu limestone. This decrease was likely due to sintering and a reduction in the number of micropores. The unusual increase in pore volume after multiple cycles was due to the formation of mesopores with smaller pore diameters. Full article

Antithrombin (AT) plays a crucial role in the human anticoagulant system and has extensive clinical applications. However, traditional detection methods often require large sample volumes, complex procedures, and lengthy processing times. Methods: We integrated digital microfluidics technology with AT detection to develop a point-of-care testing (POCT) device that is user-friendly and fully automated for real-time AT testing. Results: This device allows for automation and enhanced adaptability to various settings, requiring only a minimal sample volume (whole capillary blood), thereby omitting steps such as plasma separation to save time and improve clinical testing efficiency. Comparisons with conventional AT activity detection methods demonstrate a high degree of consistency in the results obtained with this device. Conclusion: The AT detection system we developed exhibits significant effectiveness and holds substantial research potential, positioning it to evolve into a clinically impactful POCT solution for AT assessment. Full article

Hydrogel particles, renowned for their high water content and biocompatibility in drug delivery and tissue engineering, typically rely on complex, costly microfluidic systems to reach sub 5 µm dimensions. We present a vortex-based inverse-emulsion polymerization strategy in which UV crosslinking of polyethylene glycol diacrylate (PEGDA) dispersed in n-hexadecane and squalene yields tunable micro- and nanogels while delineating the parameters that govern particle size and uniformity. Systematic variation in surfactant concentration, vessel volume, continuous phase viscosity, vortex speed and duration, oil-to-polymer ratio, polymer molecular weight, and pulsed vortexing revealed that increases in surfactant level, vortex intensity/duration, vessel volume, and oil-to-polymer ratio each reduced mean diameter and PDI, whereas higher polymer molecular weight and continuous phase viscosity broadened the size distribution. We further investigated how these same parameters can be tuned to shift particle populations between nano- and microscale regimes. Under optimized conditions, microhydrogels achieved a coefficient of variation of 0.26 and a PDI of 0.07, with excellent reproducibility, and nanogels measured 161 nm (PDI = 0.05). This rapid, cost-effective method enables precise and scalable control over hydrogel dimensions using only standard laboratory equipment, without specialized training. Full article

As three-dimensional (3D) printing becomes increasingly prevalent in microfluidic system fabrication, the demand for high precision has become critical. Among various 3D printing technologies, light-curing-based methods offer superior resolution and are particularly well suited for fabricating microfluidic channels and associated micron-scale components. Two-photon polymerization (TPP), one such method, can achieve ultra-high resolution at the submicron level. However, its severely limited printable volume and high operational costs significantly constrain its practicality for real-world applications. In contrast, digital light processing (DLP) 3D printing provides a more balanced alternative, offering operational convenience, lower cost, and print dimensions that are more compatible with practical microfluidic needs. Despite these advantages, most commercial DLP systems still struggle to fabricate intricate, high-resolution structures—particularly curve, thin-walled, or hollow ones—due to over-curing and interlayer adhesion issues. In this study, we developed a DLP-based projection micro-stereolithography (PμSL) system with a simple optical reconfiguration and fine-tuned its parameters to overcome limitations in printing precise and intricate structures. For demonstration, we selected an Archimedes microscrew as the target structure, as it serves as a key component in microfluidic micromixers. Based on our previous study, the most effective design was selected and fabricated in accordance with practical microfluidic dimensions. The PμSL system developed in this study, along with optimized parameters, provides a reference for applying DLP 3D printing in high-precision microfabrication and advancing microfluidic component development. Full article

Microfluidics is a rapidly advancing field focused on optimizing microdevices for applications such as organ-on-a-chip systems and enhancing laboratory analyses. Understanding the physical parameters of droplet generation is crucial for these devices. Computational fluid dynamics (CFD) techniques are essential for providing insights into the limitations and efficiency of numerical methods for studying fluid dynamics and improving our understanding of various application conditions. However, the influence of different numerical methods on the analysis of physical parameters in problems involving droplet generation in microchannels remains an area of ongoing research. This study implements the Volume of Fluid (VOF) method to investigate key physical parameters, including droplet size and the effect of the capillary number on fluid regimes, in droplet generation within a microchannel featuring a T-junction geometry. We compare the VOF method with the widely used Level Set Method (LSM) to evaluate its suitability for this context. The results show that the VOF method agrees with the LSM in fundamental outcomes, such as the reduction in droplet diameter as the flow rate ratio increases and the identification of the capillary number’s influence on fluid regime classification. The VOF method provides a clearer understanding of transitions between fluid regimes by detecting stages of non-uniformity in droplet size. It identifies a transition region between regimes with variations in droplet size, proving to be effective at mapping fluid flow regimes. This study highlights the potential of the VOF method in offering more detailed insights into instabilities and transitions between fluid regimes at the microscale. Full article

Droplet microfluidics has emerged as a transformative technology that can substantially increase the throughput of antibody “hit” discovery. This review provides a comprehensive overview of the recent advances in this dynamic field, focusing primarily on the technological and methodological innovations that have enhanced the antibody discovery process. This investigation starts with the fundamental principles of droplet microfluidics, emphasizing its unique capabilities for precisely controlling and manipulating picoliter-volume droplets. This discussion extends to various assay types employed in droplet microfluidics, including binding assays, functional assays, Förster Resonance Energy Transfer (FRET) assays, internalization assays, and neutralization assays, each offering distinct advantages for antibody screening and characterization. A critical examination of methods to improve droplet encapsulation is presented, besides addressing challenges such as reducing the leakage of small molecules from droplets and explaining what a “hit” droplet looks like. Furthermore, we assess design considerations essential for implementing high-throughput fluorescence-activated droplet sorting (FADS) workstations and emphasize the need for automation. This review also delves into the evolving commercial landscape, identifying key market players and emerging industry trends. This review paper aims to catalyze further research and innovation, ultimately advancing the field towards more efficient and robust solutions for antibody identification and development. Full article

Microfluidic modulation spectroscopy-infrared (MMS) offers a label-free, high-sensitivity approach for quantifying changes in protein secondary structures under native solution conditions. MMS subtracts the solvent backgrounds from sample signals by alternately flowing proteins and matched buffers through a microfluidic chamber, yielding clear amide I spectra from microliter volumes. In this study, we validated MMS on canonical globular proteins, bovine serum albumin, mCherry, and lysozyme, demonstrating accurate detection and resolution of α-helix, β-sheet, and mixed-fold structures. Applying MMS to the intrinsically disordered protein Tau, we detected environment-driven shifts in transient conformers: both the acidic (pH 2.5) and alkaline (pH 10) conditions increased the turn/unordered structures and decreased the α-helix content relative to the neutral pH, highlighting the charge-mediated destabilization of the labile motifs. Hyperphosphorylation of Tau yielded a modest decrease in the α-helical fraction and an increase in the turn/unordered structures. Comparison of monomeric and aggregated hyperphosphorylated Tau revealed a dramatic gain in β-sheet and a loss in turn/unordered structures upon amyloid fibril formation, confirming MMS’s ability to distinguish disordered monomers from amyloids. These findings establish MMS as a robust platform for detecting protein secondary structures and monitoring aggregation pathways in both folded and disordered systems. The sensitive detection of structural transitions offers opportunities for probing misfolding mechanisms and advancing our understanding of aggregation-related diseases. Full article

Conventional laboratory methods for handling valuable biological samples typically use pipettes or needles, which are prone to issues such as dead volume and sample waste. Furthermore, the sampling and processing of pathogenic bacteria, such as Escherichia coli (E. coli) in environmental wastewater, require labor-intensive procedures with multiple complex steps. To overcome these limitations, we developed a pipette integrated with a microfluidic chip for bacteria sampling and delivery. This pipette can provide the negative pressure to microfluidic chips for sampling, the constant temperature unit for biological reaction, and programs for automatic control (suction, heating, liquid discharge, and cleaning) and display. The droplet chip employs a cross-channel structure to generate droplets and incorporates a designated droplet storage and detection area. Utilizing this innovative device, we have demonstrated the generation, transportation, and storage of pL droplets, as well as quantitatively detected E. coli samples across various concentrations. The test results have demonstrated the overall reliability and data consistency of the system. Overall, our device achieves the precise sampling of pL volumes, offering a simple yet promising solution for the sampling and delivery of bio-samples in remote settings. Full article

Microfluidic devices are tiny tools used to manipulate small volumes of liquids in various fields. However, these devices frequently require additional equipment to control fluid flow, increasing the cost and complexity of the systems and limiting their potential for widespread use in low-resource biomedical applications. Here, we present a cost-effective and simple fabrication method for PMMA microfluidic chips using laser cutting technology, along with a low-cost and open-source peristaltic pump constructed with common hardware. The pump, programmed with an Arduino microcontroller, offers precise flow control in microfluidic devices for small volume applications. The developed application for controlling the peristaltic pump is user-friendly and open source. The microfluidic chip and pump system was tested using Jurkat cells. The cells were cultured for 24 h in conventional cell culture and a microfluidic chip. The LDH assay indicated higher cell viability in the microfluidic chip (111.99 ± 7.79%) compared to conventional culture (100 ± 15.80%). Apoptosis assay indicated 76.1% live cells, 18.7% early apoptosis in microfluidic culture and 99.2% live cells, with 0.5% early apoptosis in conventional culture. The findings from the LDH and apoptosis analyses demonstrated an increase in both cell proliferation and cellular stress in the microfluidic system. Despite the increased stress, the majority of cells maintained membrane integrity and continued to proliferate. In conclusion, the chip fabrication method and the pump offer advantages, including design flexibility and precise flow rate control. This study promises solutions that can be tailored to specific needs for biomedical applications. Full article

Micromixing is a crucial process in microfluidic systems. In biochemical and chemical analysis, the sample is usually tested with reagents. These solutions must be well mixed for the reaction to be possible, generally using micromixers manufactured with sophisticated and expensive technology. The present work shows the design and evaluation of micromixers fabricated with LTCC (low-temperature co-fired ceramics) and FDM (fused deposition modeling) technologies for the development of functional and complex geometries. Two-dimensional planar serpentine and 3D chaotic convection serpentine micromixers were manufactured and implemented in an automated microanalytical system using photometric methods. To evaluate the performance of the micromixers, flow, mixing and absorbance measurements were carried out. Green tape and PP materials were used and showed good resistance to the acidic chemical solutions. The devices presented achieved mixing times in seconds, a reduced dispersion due to their aspect ratio, high sensitivity, and precision in photometric measurement. The optical sensing cells stored sample volumes in a range of 10 to 600 µL, which allowed the reduction of reagent consumption and waste generation. These are ideal characteristics for in situ measurement, portable, and low-cost applications focused on green chemistry and biochemistry. Full article

Continuous-flow microfluidic biochips (CFMBs) automatically execute various bioassays by precisely controlling the transport of fluid samples, which is driven by pressure delivered through fluidic ports. High-level synthesis, as an important stage in the design flow of CFMBs, generates binding and scheduling solutions whose quality directly affects the efficiency of the execution of bioassays. Existing high-level synthesis methods perform numerous transport tasks concurrently to increase efficiency. However, fluidic ports cannot be shared between concurrently executing transport tasks, resulting in a large number of fluidic ports introduced by existing methods. Increasing the number of fluidic ports undermines the integration, reduces the reliability, and increases the manufacturing cost. In this paper, we propose a port-driven high-level synthesis method based on integer linear programming (ILP) called SlimPort, integrating the optimization of fluidic port number into high-level synthesis, which has never been considered in prior work. Meanwhile, to ensure bioassay correctness, volume management between devices with a non-fixed input/output ratio is realized. Additionally, two acceleration strategies for ILP, scheduling constraint reduction and upper boundary estimation of fluidic port number, are proposed to improve the efficiency of SlimPort. Experimental results from multiple benchmarks demonstrate that SlimPort leads to high assay execution efficiency and a low number of fluidic ports. Full article

Background: The mechanical conditioning (MeCo) score is a multigene expression signature that is acquired by cancer cells in the primary breast tumor and is reflective of their responsiveness to ECM stiffness caused by tumor fibrosis. Chromatin remodeling downstream of mechanotransduction allows cancer cells to retain these acquired aggressive features even in the absence of mechanical stimulation from the primary tumor microenvironment, for instance, after dissemination through systemic circulation during metastasis. Importantly, patients who have high MeCo score tumors are at higher risk of developing metastatic breast cancer, compared to those with low MeCo scores. Moreover, circulating tumor cells (CTCs) are associated with a higher rate of metastatic dissemination, making CTC detection in the circulation of patients with breast cancer a significant prognostic biomarker for breast cancer metastasis. Beyond their enumeration per blood volume units, specific prognostic features of CTCs are not fully explored. We sought to determine whether MeCo scores increase stepwise along the metastatic cascade, from primary tumors to CTCs to distant metastatic colonization, using patient-matched biopsies. Methods: CTCs were isolated from the peripheral blood of two patient cohorts: patients with early-stage breast cancer using immunomagnetic enrichment/FACS methodology; and patients with late-stage breast cancer using the ANGLE Parsortix microfluidics system. Gene expression profiling using RNA-seq was performed on CTCs and matched primary tumors (PTs) in the early-stage cohort, and on CTCs and matched metastases (METs) for the late-stage cohorts. A quantile normalization approach was used to allow comparison across cohorts and MeCo scores were computed for all samples. The Wilcoxon matched-pairs signed rank test was performed for the comparison of MeCo scores from matching samples within each cohort; the Mann–Whitney unpaired test was used to compare MeCo scores of CTCs across cohorts. Results: In 12 pairs of patients with early-stage breast cancer, MeCo scores in CTCs were significantly higher than in their matched PTs (p = 0.026). Additionally, in 26 pairs of metastatic patient CTCs and METs, MeCo scores were significantly higher in METs compared to matched CTCs (p = 0.0004). MeCo scores of CTCs were similar between patients with early- and late-stage breast cancers, despite differing CTC isolation strategies (epitope-dependent and microfluidics size gradient). Notably, 98% of the genes in the MeCo score were present across evaluable CTC, MET, and PT samples. Conclusions: Our results show that the MeCo score is higher in CTCs than in PTs, and higher in METs compared to CTCs, in early- and late-stage breast cancer, respectively (i.e., PT < CTC < MET). Therefore, the MeCo score is progressively higher throughout the metastatic cascade in breast cancer. These findings demonstrate that mechanical conditioning from primary tumors is retained during metastatic progression, after mechanical induction by ECM stiffness is lost, as cancer cells disseminate through systemic circulation. Additionally, these findings support that cancer cells with higher MeCo scores are more competent with—and potentially selected for—metastatic progression. Importantly, these findings provide a novel feature of CTCs, mechanical conditioning (MeCo), which is associated with higher capacity for metastasis. Furthermore, since the CTC MeCo score is elevated even in early-stage breast cancer, it could provide, in addition to CTC enumeration, a potential prognostic indicator to improve metastatic risk assessment in early disease. Full article

Understanding cancer etiology requires replicating the tumor microenvironment (TME), which significantly differs from standard in vitro cultures due to nutrient limitations, acidic pH, and oxidative stress. To address this, a microfluidic bioreactor (µBR) with an expanded culture surface was designed to optimize exosome enrichment and glioblastoma cell behavior. Using response surface methodology (RSM), key parameters—including medium exchange volume and interval time—were optimized, leading to about a six-fold increase in exosome concentration without artificial inducers. Characterization techniques (SEM, AFM, DLS, RT-qPCR, and ELISA) confirmed significant alterations in exosome profiles, cancer stemness, and epithelial-mesenchymal transition (EMT)-related markers. Notably, EMT was induced in the µBR system, with a six-fold increase in HIF-1α protein despite normoxic conditions, suggesting activation of compensatory signaling pathways. Molecular analysis showed upregulation of SOX2, OCT4, and Notch1, with SOX2 protein reaching 28 ng/mL, while it was undetectable in traditional culture. Notch1 concentration tripled in the µBR system, correlating with enhanced stemness and phenotypic heterogeneity. Immunofluorescent microscopy confirmed nuclear SOX2 accumulation and co-expression of SOX2 and HIF-1α in dedifferentiated CSC-like cells, demonstrating tumor heterogeneity. These findings highlight the µBR’s ability to enhance stemness and mimic glioblastoma’s aggressive phenotype, establishing it as a valuable platform for tumor modeling and therapeutic development. Full article