Thermal lamination and laser cut (TLLC) method for enclosed Micro-fluidic paper analytical devices (μPADs) by controlled ablation

In a non-uniform electric field, particles show dielectrophoretic (DEP) behavior. This is a phenomenon where particles are attracted or repelled by the electric field depending on their electrical properties, size, the surrounding medium, and the frequency of the applied field. These effects are called positive or negative dielectrophoresis, corresponding to attraction toward or repulsion from the electrodes, respectively. With the right frequency, the particles can be manipulated, separated, or collected, based on their characteristics. We designed and simulated three types of electrodes: "fishbone," "snake," and "sine" structures, and integrated them into microfluidic channels. The electrodes were designed to direct the micron/submicron-sized particles by positive DEP force to the center of the channel, enabling their specific collection and concentration at the outlet. For comparison, we calculated the DEP force for each electrode design, and simulated the particle trajectories within the device. Additionally, we fabricated these devices and experimentally measured their particle collecting efficiency. • Design and fabrication of custom-made electrodes and microfluidic channels • COMSOL simulations for the dielectrophoretic (DEP) force range and particle tracing • Demonstration experiments with 1 µm and 0.1 µm microspheres

Graphene oxide-integrated double-stranded DNA mismatch regulation on a microfluidic paper-based device for ultrasensitive fluorescent detection of Vibrio parahaemolyticus and Shigella flexneri

Biomimetic MOF/MIPs carbohydrate microfluidic paper chip: A versatile sialic acid detection platform from point-of-care screening to food rapid analysis.

From annular to surface bubbles: unraveling wettability-controlled flow patterns and governing mechanisms in microchannels

Plant root-associated anoxic microsites may influence the fate of nutrients and contaminants in the rhizosphere, but their dynamics remain relatively unknown. To examine the formation of root-induced anoxic microsites over space and time, we use microfluidic devices integrated with transparent, planar oxygen sensors in a wheat (Triticum aestivum) rhizosphere, with and without soil microorganisms. We found that suboxic (< 2% air saturation) conditions commonly establish at root tips and more rarely establish along more mature root segments, particularly in the presence of soil organic matter and complex microbial communities. Additionally, the distribution of oxygen, and thus root-induced anoxic microsites, depends on complex interactions among light-dark cycles, growth rate, and presence of microorganisms in the rhizosphere. This study provides real-time observations of the micron-scale oxygen dynamics around actively growing roots, thereby linking root physiology to anoxic microsite formation in the rhizosphere. Our work suggests a strong potential for root-driven anoxic microsite formation, prompting important questions about anoxic microsite impact on biogeochemical processes in natural rhizosphere soil.

In vitro models of oral dysplasia fail to recapitulate physiologically relevant tissue-tissue interfaces and other microenvironmental cues. This study aimed to present a preliminary organ-on-a-chip (OoC) model of a precancerous oral cavity lesion (OD-OoC). The objective was to reproduce in a two-channel microfluidic device an in vitro tridimensional (3D) model characterized by an organized interaction between endothelial cells, fibroblasts, and dysplastic oral keratinocytes on a collagen I-coated membrane. On day 1, human umbilical vein endothelial cells (ECs) were introduced in the bottom channel, and the chip was inverted to allow cell adhesion to the lower side of the membrane. The chip was then inverted back to the original position, and human gingival fibroblasts (hGFs) were introduced into the top channel. On day 2, the laminar flow was activated, while uniform layers of hGFs and ECs were forming in the respective channels. On day 3, dysplastic oral keratinocytes (DOKs) were inoculated in the top channel above the hGFs layer. On day 5, the chip was fixed with 4 % paraformaldehyde and stained with antibodies targeting podoplanin, Trop2, and VE-cadherin for staining of hGFS, ECs, and DOKs, respectively. Confocal microscopy confirmed the presence of all cell types, showing fibroblast migration from the top channel to the bottom channel of the chip, where they localized between the membrane and the ECs. DOKs confined to the top channel showed slight and uneven E-cadherin and EpCAM (Epithelial Cell Adhesion Molecule) positivity, but evident positivity for Trop-2, confirming that their phenotype differed from that of healthy epithelial cells. The presented OD-OoC could enable in vitro monitoring of epithelial cell phenotype changes and cell migration across the membrane, suggesting its potential applicability in future oral cancer research.

The surfactant-free sol-gel synthesis of hydroxyapatite nanoparticles was adapted for in-flow production using a capillary-based microfluidic device. Different parameters have been investigated, including the capillary arrangements (core-shell and side-by-side), the capillary diameter, and the flow rate of the precursor solutions. The nanoparticles synthesized were characterized by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and specific surface area measurement according to the Brunauer-Emmett-Teller (BET) theory. The results were compared with those of hydroxyapatite nanoparticles obtained by the conventional batch sol-gel synthesis method. The morphology of the nanoparticles changed due to the use of different capillary arrangements and thus exhibited a higher specific surface area than the batch process. The highest specific surface area was observed when using a side-by-side arrangement using a capillary with an internal diameter of 100 μm and a flow rate of 100 μL/min reaching an increase of the specific surface area by two-fold (61 m 2 /g) as compared to the conventional batch sol-gel method (29 m 2 /g) without affecting any of their other properties including cell viability. • No surfactant was used to synthesize hydroxyapatite nanoparticles. • The specific surface area was higher by microfluidics as compared to the batch mode (29 m 2 /g). • The side-by-side capillary arrangement led to the more promising results (61 m 2 /g).

Understanding microbial growth and metabolism under controlled environments is critical for both fundamental research and bioprocess development. In this study, we present a cost-effective droplet-based microfluidic device enabling high-throughput screening of GFP expression in Escherichia coli (E. coli) under varying glucose concentrations. Fluorinated Ethylene Propylene (FEP) tubing was selected for its low cost and compatibility with stable water-in-oil emulsification, facilitating robust droplet generation. The system achieved a 33333-fold reduction in media consumption compared to traditional Erlenmeyer flask cultures. Growth kinetics and GFP expression were assessed in both Erlenmeyer flasks and microdroplets, showing high qualitative correlation between platforms. Low glucose levels (5-10 g/L) supported rapid initial growth and early GFP production, followed by a fluorescence decline due to nutrient depletion. In contrast, higher glucose concentrations (25-50 g/L) prolonged the exponential phase and enhanced GFP production per unit biomass, though growth was slowed by overflow metabolism. In microdroplets, delayed GFP expression at 25 and 50 g/L were observed, and parallel bioreactor experiments confirmed that this delay is caused by oxygen limitation at high glucose concentrations. Importantly, the microfluidic device enables controlled variation of oxygen availability simply by adjusting droplet size or generation frequency, providing a powerful means to probe oxygen-sensitive metabolic behaviors. These results validate the microfluidic platform's ability to mimic Erlenmeyer flask-scale dynamics, while uniquely allowing precise modulation of oxygen transfer conditions at the microscale. The system offers a reliable, miniaturized alternative for optimizing microbial bioprocesses with drastically reduced reagent use and increased experimental throughput.

Constructing combinatorially complete species assemblages is often necessary to dissect the complexity of microbial interactions and to find optimal microbial consortia. At the moment, this is accomplished through either painstaking, labor-intensive liquid handling procedures, or through the use of state-of-the-art microfluidic devices. Here, we present a simple, rapid, low-cost, and highly accessible liquid handling methodology for assembling all possible combinations of a library of microbial strains, which can be implemented with basic laboratory equipment. To demonstrate the usefulness of this methodology, we construct a combinatorially complete set of consortia from a library of eight Pseudomonas aeruginosa strains, and empirically measure the community-function landscape of biomass productivity, identify the highest-yield community, and dissect the interactions that lead to its optimal function. This easy-to-implement, inexpensive methodology will make the assembly of combinatorially complete microbial consortia easily accessible for all laboratories.

Clinical hollow-fiber artificial lungs are prone to clotting, necessitating the use of systemic anticoagulation and thus increasing the risk of bleeding events. This study seeks to address these limitations by creating hemocompatible and biomimetic 3D-printed artificial lungs. This study investigates the nonthrombogenic effects of imbuing a polydimethylsiloxane (PDMS or silicone elastomer)-based 3D-printable resin with hydrophilic molecules with the goal of reducing the body's natural coagulation response to foreign materials, increasing device lifetime, and reducing systemic anticoagulation, thereby coming closer to mimicking the native in vivo blood interface. First, contact angle (hydrophilicity) tests were done to narrow down the number of candidate modifications for the development of a high-resolution PDMS resin for vat photopolymerization (VPP). Then, dynamic blood flow-through testing was performed using a high-resolution PDMS base resin modified by (1) adding 1% 2-methacryloyloxyethyl phosphorylcholine (MPC) to the base resin; (2) adding 1.8% poly(ethylene glycol) methacrylate (PEGMA) to the base resin; or (3) infusing the neat PDMS devices with 2% dimethylsiloxane-[60-70% ethylene oxide] (PEO-PDMS) in ethanol post printing. Biomimetic microfluidic capillary devices designed in SOLIDWORKS were 3D-printed via VPP, cleared of uncured resin, and tested for coagulation with freshly drawn ovine whole blood. Devices (n ≥ 12 per group) were exposed to blood for 10 min at 0.8 mL/min and evaluated for clotting via fluorescent confocal microscopy, percent clotting area analyses, pressure data, and flow cytometry. The 1% MPC, 1.8% PEGMA, and 2% PEO-PDMS infusion resin groups demonstrated a significant decrease in clotting area and fluorescence intensity when compared to the unmodified base resin and a commercially available resin (FTD Nano Clear). The top-performing modification (PEO-PDMS infusion) decreased the clotting area by 57.5 and 65.2% and fluorescence intensity by 84.6 and 88.3% relative to the unmodified base resin and FTD Nano Clear resin, respectively.

Cervical cancer is one of the most common malignant tumors in women. Persistent high-risk human papillomavirus (hrHPV) infection is the cause of nearly all cervical cancers. Routine cervical cancer screening is the most impactful intervention to prevent their progression to invasive disease, but current methods are time-consuming, are labor-intensive, rely on a complex laboratory infrastructure, and are unsuitable for frequent deployment in resource-limited settings. Here, we introduce droplet digital-enhanced Pyrococcus furiosus Argonaute detection (ddPfAgo), a novel nucleic acid detection platform that combines Ago nucleic acid detection with a digital assay. ddPfAgo utilizes the heat-activated cleavage activity of PfAgo to achieve highly selective and efficient double-stranded target DNA recognition without relying on PAM. Through vortex-assisted droplet generation and an ImageJ-based data analysis workflow, ddPfAgo enables the multiplexed detection of HPV16 and HPV18 rapidly within 30 min, without the need for complex microfluidic devices and advanced computational resources. Harnessing the absolute quantification capability of a digital platform, the ddPfAgo achieved detection sensitivity at the femtomolar level (detection limit of 50 fM), representing a 106-fold improvement over traditional solution-based PfAgo methods. Clinical validation confirmed ddPfAgo's high diagnostic accuracy, with test results being 100% consistent with qPCR, demonstrating its great application potential in clinical diagnosis.

The inherent capacity to flexibly reorganize after injury is a hallmark of brain networks, with recent studies suggesting that the functional consequences of damage are strongly influenced by the network's nonrandom connectivity. However, experimental platforms that enable bottom-up investigations of the structure-function relationships underlying damage and recovery processes remain limited. Here, we used polydimethylsiloxane microfluidic devices to construct hierarchically modular neuronal networks that mimic the topological features of the mammalian cortex. Laser microdissection was employed to selectively sever intermodular connections, enabling controlled damage to either hub or peripheral connections. Damage to hub connections leads to delayed recovery, requiring more than three days for correlations to re-emerge. Contrarily, peripheral damage resulted in faster recovery. Repeated injury to neuronal networks further revealed that recovery occurs through both new pathway formation and restoration of originals. These findings provide mechanistic insights into the intrinsic self-repair capacity of living neuronal networks.

The electrophoretic velocity of a charged dielectric particle is independent of its size and shape in a Newtonian fluid under the thin Debye layer limit in the weak-field regime. Our previous paper (Bentor and Xuan, Analytical Chemistry 2024, 96, 3186-3191) reported particle size-dependent electrophoresis in viscoelastic poly(ethylene oxide) (PEO) solutions. We demonstrate herein that the fluid elasticity also induces the particle shape dependence of electrophoretic velocity likely because the polymer stress around a particle varies with its shape. Specifically, altering the shape of a particle from sphere to pear and peanut enhances the electrophoretic velocity in a viscoelastic fluid as the particle becomes slenderer. This phenomenon, which is found absent from a Newtonian fluid, becomes stronger in higher-concentration PEO solutions because of the enhanced fluid elasticity effect. It may be utilized for the label-free electrophoretic separation of particles and cells in non-Newtonian microfluidic devices.

Internal temperature measurements are vital for the development in the industrial, electronic, and aerospace fields for a variety of applications, from heat exchangers to material selection. Specifically, advancements in additive manufacturing and 3D printing have enabled these fields to rapidly prototype and produce complex geometries at much lower costs. However, these designs will require testing and validation via internal temperature measurements before widespread use, which is further complicated by the increased complexity. These internal temperature measurements will ideally have spatial and temporal resolutions to aid calculations such as heat transfer. This study proposes a temperature-sensitive resin (TSR) by combining a commercially available 3D-curable resin with a thermographic luminophore and demonstrates that the TSR layer is temperature sensitive. It is demonstrated that the TSR can be used with a commercially available 3D printer and that testing equipment can measure the internal temperature along a 2D slice of a 3D-printed model by monitoring luminescent output. This temperature-sensitive resin and measurement technique, if further developed, may provide internal temperature measurements with high spatial and temporal resolution for potential use in the development of items such as heat exchangers, microfluidic devices, and aerospace bodies.

Microfluidic paper-based analytical devices (µPADs) are an attractive format for colorimetric nucleic acid amplification tests (NAATs) because they enable low-cost, portable diagnostics in resource-limited settings. However, researchers often optimize colorimetric assays in liquid reactions in tubes before translating them to µPADs. Since both formats require separate instruments for incubation and real-time sensing, direct comparison of reactions between the two formats is difficult. To address these cross-platform limitations, we developed ThermiQuant™ AquaStream, a portable benchtop device (15 × 20 × 16 cm, ~ 5 kg; cost: USD 327) that supports seamless colorimetric loop-mediated isothermal amplification (LAMP) reactions in both µPADs and tubes under a common workflow. The system enables real-time reaction tracking (every 30 seconds) through onboard image processing, precise isothermal control (±0.5 °C) using a repurposed consumer-grade sous-vide heater, and medium-throughput (24 tubes or 42 µPADs). Testing with synthetic SARS-CoV-2 orf7ab DNA fragments demonstrated a limit of detection corresponding to a 95% probability of detection (LOD95) of 110 copies per reaction in tube (22 copies/µL) and 39 copies per reaction in µPADs (5 copies/µL), estimated using probit regression. In both formats the limit of quantification (LOQ), defined as the lowest concentration yielding a coefficient of variation (CV) of quantification time (Tq) ≤ 10%, was 250 copies/reaction resulting in a strong linear (R2 = 0.98 & R2 = 0.96 respectively for tube and µPADs) standard calibration curves. ThermiQuant™ AquaStream provides an affordable and versatile benchtop platform capable of supporting both tube- and µPAD-based colorimetric LAMP assays, serving as a proof-of-concept research tool for assay development and molecular diagnostics in One Health settings such as clinics, farms, and field environments.

Baker’s yeast is a common microorganism that is well-known for its fermentation activities. The fermentation process naturally produces CO2, leading to a gradual increase in internal pressure within sealed environments. Meanwhile, passive pumps are rising in the microfluidics field for their simplicity, low energy requirements, and suitability for portable and disposable devices. Here, we harnessed yeast fermentation as a biological power source for a passive pump, enabling fluid flow in microfluidic systems. This approach introduces a cost-effective solution and extends the concept of passive pumping into the realm of biological systems. The custom mechanical pump operates by converting the gas pressure generated by fermentation into continuous fluid movement. The dynamics of gas production within the pump were analyzed experimentally to characterize performance over time. The resulting six-parameter and four-parameter equations accurately capture the experimental trends within the validated operating range. This model was further extended to a simplified two-parameter form—using only yeast mass and sucrose concentration—making the pump setup more intuitive. This biologically driven pump concept holds potential for expansion into autonomous microfluidic devices, especially for space orbital experiment modules, educational tools, or low-resource settings where external power sources are limited.

We numerically study the escape kinetics of an elliptical Brownian particle from two-dimensional cavities with various pore structures and geometries. We emphasize a scenario in which the pore size is smaller than the particle's largest diameter yet slightly larger than its shortest diameter. In this case, the particle must adopt a specific orientation to exit through the narrow pore. Our simulation results indicate that, in addition to the particle's aspect ratio and pore structure, its rotational dynamics play a crucial role in the escape kinetics. We observed that, for flattened pore tips, the mean first passage time as a function of rotational diffusion exhibits a minimum, akin to the phenomenon of resonant activation. In the limit of very slow rotational diffusion, the mean escape time is directly proportional to the rotational relaxation time, irrespective of the pore structure. On the other hand, in the fast rotational limit, the mean exit time is inversely proportional to the square root of the rotational relaxation time for flattened pore tips. Additionally, the divergence behavior of the mean exit time as the pore size tends to zero depends largely on the rotational dynamics, in addition to the pore structure. Beyond direct applications in microfluidic devices and nanotechnology, our simulation results may also help in understanding the diffusion of living or artificial micro/nano nonspherical objects, such as bacteria, viruses, and Janus rods, where rotational relaxation time plays a significant role.

Multi-potential laser-induced graphene fluidic paper-based array for in-flow differential analysis of phenolic compounds.

Life sustains complex functions through intercellular communication networks that coordinate collective behavior and regulate environmental homeostasis. Replicating such dynamic and autonomous control over extended spatial and temporal domains in synthetic materials remains significant challenges. Here, we present a programmable dual-microcapsule system that emulates life-like homeostatic pH regulation via an antagonistic enzymatic network. The system integrates urease microcapsules (UMCs) and esterase microcapsules (EMCs), which were produced using microfluidic devices coupled with a surface co-assembly strategy. By integrating hybrid junction geometry with a modified epoxy post-coating strategy, the 3D-printed microfluidic device overcomes intrinsic structural defects and surface irregularities. The resulting amphiphobic and defect-free channels ensure stable droplet production and precise microsphere fabrication. Individual capsules display pH-mediated negative feedback through adaptive shell permeability, whereas mixed populations display communicate behaviors via pH signaling to generate programmable pH oscillations and feedback-controlled pH stabilization. This platform exhibits robust reaction to external pH control, long-term cycling stability, and inter-capsule interaction. This work offers a versatile route for engineering communicative, autonomous, and adaptive material systems, with broad implications for biomedical devices, environmental regulation, and soft control using chemical information exchange.