Lab on a Chip最新文献

Correction for 'Mechanical forces and enzymatic digestion act together to induce the remodeling of collagen fibrils in tumor microenvironment' by Jiling Shi et al., Lab Chip, 2025, https://doi.org/10.1039/d4lc00821a.

Lithium is the first-line treatment for bipolar disorder. However, the narrow therapeutic window of serum (s-)lithium is near its toxicity range, necessitating continuous monitoring of patients, a process involving regular hospital visits. On-demand home sampling could allow for more frequent testing, possibly resulting in safer patient outcomes, further dosage optimization, and increased compliance. This article presents a device that measures the s-lithium concentration from whole blood. The device consists of a single-use cartridge able to conduct on-chip serum filtration, volume-metering and an on-chip colorimetric assay. Spiked whole blood shows good linearity (Pearson's r = 0.96, R² = 0.92), a limit-of-detection of 0.3 mmol L^-1, and an average deviation of 0.05 mmol L^-1 (±6%) compared to atomic absorption spectroscopy. The on-chip colorimetric assay has shown to be a promising technique for measuring s-lithium concentration from whole blood and could allow patients to assess lithium levels at home and make the treatment available for new patient groups.

Polydimethylsiloxane (PDMS) chips are still the workhorses of academic microfluidics. Their production requires the fabrication of moulds, commonly produced using clean-room technologies. Light-based 3D printing and in particular, vat photopolymerization, material jetting and two-photon polymerization are rising techniques for the fabrication of moulds for PDMS replication, thanks to their accessibility, fast prototyping time, and improving resolution. Here, we are first reviewing the possibility opened by 3D printing for soft lithography, with a focus on mould designs. Then, inhibition of PDMS curing by photosensitive resins will be discussed as the main technical hurdle of 3D printed moulds. Fortunately, mould post-treatments are efficient solutions to eliminate this curing inhibition, which we gathered in a large database of post-treatment protocols from the literature.

Correction for 'Functionality integration in stereolithography 3D printed microfluidics using a "print-pause-print" strategy' by Matthieu Sagot et al., Lab Chip, 2024, 24, 3508-3520, https://doi.org/10.1039/D4LC00147H.

Microfluidics is a key tool for studying pore-scale phenomena in porous media, with applications in oil recovery and carbon storage. However, accurately replicating rock pore structures in quasi-2D microfluidic platforms remains a challenge. Existing design strategies, including regular and irregular networks, fractal geometries, thin-section imaging, and multi-step methods using CT scans and SEM images, often fail to capture real pore space morphologies. To address these issues, we developed a multi-step workflow that preserves pore morphology and size distributions in quasi-2D microchips (rock-on-a-chip) by generating 2D pore throats from 3D network data of CT-scanned rock samples. The method showed strong agreement between 2D and 3D pore and throat size distributions in both designed patterns and fabricated microchips. A critical factor in achieving accurate pore geometry was precise mask alignment, which enabled the fabrication of microchips with narrower throats for relatively tight reservoir patterns. Permeability regulation was achieved by adjusting inlet areas while maintaining pore and throat size distributions similar to the original 3D subvolume. Flow simulations using the Hagen-Poiseuille equation within the OpenPNM framework showed differences between simulated and experimental permeability, especially in low-permeability designs, which were more sensitive to the etching process. Despite these challenges, the proposed approach minimizes common discrepancies between rock pore space morphologies and quasi-2D microchips, significantly improving the reliability of microfluidic studies for applications requiring accurate pore-scale structures.

Over the past 30 years, organs-on-a-chip (OOCs) have emerged as a robust alternative to address the technological challenges associated with current in vitro and in vivo options. Although OOCs offer improved bio-relevance and controlled complexity, broad adoption has remained limited. Most approaches to characterize on-chip structure and function require human intervention, limiting device translation and feasibility. Here, we introduce a new fiber optic-based sensing platform that enables automated, temporal luminescence sensing on-chip, validated for real-time readout of epithelial and endothelial barrier function under cytokine-induced inflammation. Our platform, capable of at least 1 μM resolution, tracked paracellular transport in situ for 9 days of culture under perfusion on-chip. These results offer an alternative sensing approach for continuous, non-invasive luminescence monitoring in OOCs.

Interactions between tumors and adjacent blood vessels are critical in the tumor microenvironment (TME) for influencing angiogenesis and hematogenous metastasis. Understanding these interactions within the native TME is vital for targeting various tumors, including brain tumors, due to the complexities of the blood-brain barrier. Developing an accurate tumor model that includes cell-cell and cell-matrix interactions, as well as blood flow-induced shear stress, is essential for high-throughput screening (HTS) of anti-cancer drugs. Here, we developed a glioblastoma (GBM) model surrounded by vascular cells. The arterial model was constructed by encapsulating GBM spheroids with layers of human smooth muscle cells (SMCs) and human umbilical vein endothelial cells (HUVECs), while the capillary cell layered model used only HUVECs. Comparative analysis with tumors from different organs revealed the significant role for platelet endothelial cell adhesion molecule (PECAM) in GBM-blood vascular cell interactions. Cytokine secretion analysis demonstrated PECAM's impact on tumor-specific angiogenic potential. Testing with anti-cancer drugs revealed increased expression of PECAM-associated proteins, drug resistance cytokines, and genes associated with tumor progression and metastasis. Additionally, we developed a HTS platform by encapsulating these tumor models in hydrogels and subjecting them to media circulation, effectively mimicking the dynamic TME, suitable for cancer treatment research and drug development.

Wearable sweat analysis using microfluidics offers a non-invasive approach for real-time health monitoring, with applications in chronic disease management, athletic performance optimization, and early-stage condition detection. However, most existing wearable sweat microfluidic devices are limited to single-mode operation either real-time or on-demand sampling and often lack precise control over sample volume, which compromises analytical accuracy and utility. To address these limitations, we present a novel wearable microfluidic device featuring a manual rotating fluid control mechanism and a finger-actuated pump for dual-mode sweat sampling. The rotational control mechanism directs sweat either into detection chambers for volume-independent sensor reactions or through the finger-actuated pump for precise volume control. The pump incorporates a dedicated collection chamber, enabling sweat accumulation and controlled delivery in a single actuation, ensuring reproducible sample volumes and facilitating on-demand analysis when required. Additionally, the device integrates two reaction chambers for simultaneous dual biomarker detection. Performance validation during a 40 minute exercise session, using a colorimetric glucose assay, demonstrated reliable sweat sampling and on-demand biochemical analysis. These results highlight the device's potential as a practical tool for personalized health monitoring and field applications.

The manipulation of micro and nanoparticles has extensive applications in biomedical research, clinical diagnostics, environmental monitoring, drug discovery, and the mining industry. Dielectrophoresis (DEP) utilises nonuniform electric fields to manipulate particles, offering a label-free, high-precision, and non-invasive method for both natural and synthetic particles. DEP manipulation has been well studied in the Stokes flow region with ultra-low Reynolds numbers (Re ≪ 1), where viscous effects dominate. However, its application in the inertial flow regime remains largely unexplored. This study aims to bridge the gap by coupling DEP and inertial flow for the manipulation of particles across micro and nano scales. First, we theoretically analysed the physical coupling of DEP and inertial lift forces along the vertical direction in microchannels, utilising symmetrical interdigitated electrode (IDE) arrays patterned on the top and bottom channel surfaces. We then experimentally investigated how the vertical coupling of DEP and inertial lift forces affects particle lateral focusing properties. The effects of DEP along the vertical direction were leveraged and amplified by the inertial effects along the lateral direction. Finally, we applied DEP in the inertial flow regime for size-based and dielectric property-based separation of particles and cells, as well as nanoparticle focusing and filtration. We believe that leveraging DEP in inertial flow will advance the field by providing a versatile and powerful method for the manipulation of micro and nanoparticles.

As traditional two-dimensional (2D) cell cultures offer limited predictive capabilities for drug development, three-dimensional (3D) tissue models, such as spherical microtissues, have been introduced to better reproduce physiological conditions. The hanging-drop method, used to cultivate microtissues at an air-liquid interface, proves to be effective for microtissue formation and maintenance. Using that technology, it is possible to fluidically interconnect several hanging drops hosting different models of human organs to recapitulate relevant tissue interactions. Here, we combine microfluidics with microelectronics (i.e., complementary metal-oxide-semiconductor (CMOS) technology) and present a novel multifunctional CMOS microelectrode array (MEA) integrated into an open microfluidic system. The device can be used in hanging-drop mode for in situ microtissue readouts and in standing-drop mode like a conventional MEA. The CMOS-MEA chip features two reconfigurable electrode arrays with 1024 electrodes each, and enables electrophysiology, impedance spectroscopy, and electrochemical sensing to acquire a broad spectrum of biologically relevant information. We fabricated the chip using a 0.18 μm CMOS process and developed a strategy to integrate the CMOS-MEA chip into the open microfluidic system within a larger overall effort to incorporate discrete CMOS sensors into microfluidic devices. Proof-of-concept experiments demonstrate the capability to perform electrophysiology and impedance spectroscopy of human induced pluripotent stem cell (hiPSC)-derived cardiac microtissues, as well as electrochemical sensing of different analytes including hydrogen peroxide and epinephrine.