Lab on a Chip最新文献

Skin fibrosis results from excessive extracellular matrix (ECM) deposition and tissue remodeling due to persistent inflammation and mechanotransduction dysregulation. Current in vivo animal models lack human relevance, while conventional 2D and 3D in vitro models misrepresent physiological mechanical forces. To address this gap, we developed a miniaturized edgeless-skin chip (ESC) platform with gravity-driven perfusion, enabling enhanced biomechanical mimicry for fibrosis modeling. ESCs present bioengineered skin grown around a 3D-printed scaffold, mimicking the continuous geometry of human skin and in vivo mechanical balance. Compared to conventional skin constructs (CSCs) that have open boundaries on all sides, ESCs exhibited higher sensitivity to TGF-β1, leading to increased ECM deposition, myofibroblast activation, YAP signaling upregulation, matrix stiffness and reduced hydraulic permeability. Inhibiting YAP signaling with verteporfin (VTP) reduced collagen deposition, prevented tissue stiffening, and attenuated several fibrosis markers, confirming the role of mechanotransduction in fibrosis progression using human cells. Transcriptome analysis revealed upregulation of fibrosis-associated genes, including COL10A1, COL11A1, and ACTA2, counterbalanced by elevation of anti-fibrotic regulators such as DKK2, which suggests the activation of negative feedback mechanisms. These findings establish the ESC platform as a robust human-relevant mechanomimetic model for studying fibrosis and evaluating anti-fibrotic therapies, addressing a critical need for translational drug discovery.

A common issue faced by magnetic particle-based lab-on-a-chip systems, e.g., for medical diagnostics, is the intrinsic fabrication-related polydispersity in particle sizes and magnetic properties. Therefore, to reduce this variation, it is prudent to integrate a pre-separation procedure for the particles into the overall workflow of the system. In this work, a concept for the controlled on-chip fractionation of micron-sized superparamagnetic beads (SPBs) is introduced, which is applicable for sorting magnetic particles according to their properties in a continuous operation mode. A specifically designed magnetic domain pattern is imprinted into an exchange-biased thin film system to generate a tailored magnetic stray field landscape (MFL), enabling lateral transport of SPBs when superposing the MFL with external magnetic field pulses. The domain pattern consists of parallel stripes with gradually increasing and decreasing width, resulting in a step-wise jumping motion of SPBs with increasing/decreasing jump distance. SPBs with different magnetophoretic mobilities, determined, among others, by the particle size and magnetic susceptibility, discontinue their lateral motion at different jump distances, i.e., different lateral positions on the substrate. Thorough analysis of the motion using optical microscopy and particle tracking revealed that an increasing stripe width not only leads to a larger jump distance but also to a lowered jump velocity. As a consequence, particles are spatially separated according to their magnetic and structural properties with a large throughput and time efficiency, as simultaneous sorting occurs for all particles present on the substrate using a constant sequence of short external field pulses.

A novel microfluidic multichannel (4×) electrochemical cell (MMEC) was developed and used for multiplexed determination of compounds related to water quality. These include heavy metals (lead and mercury ions), catechol and hydrogen peroxide. No crosstalk between the channels of the MMEC was observed. This enabled the specific and independent modification of each MMEC channel with respect to the targeted analyte. Namely, the mercury ions were determined at the bare gold (Au) electrode, lead ions were determined at the Au electrode coated with a thin mercury film (MF), H₂O₂ was determined at the Au electrode electrodeposited with gold nanostructures (AuNS), and catechol at the Au electrode modified with polyurea (PU) and AuNS. The limits of detection (LODs) were determined and found to be 0.9 ppb, 0.1 ppb, 0.4 μM, and 1.6 μM for lead and mercury ions, catechol, and hydrogen peroxide, respectively. The MMEC was applied for the detection of the analytes in river water samples and in industrial wastewater and good recovery rates were obtained: from 91.8% to 109% in river water samples and 81.8% to 111.6% in industrial wastewater. In addition, comparison with the reference method (ICP-OES) was performed for the determination of Pb²⁺ ions and the relative error was found to be smaller than 5%. This allows the MMEC to be used for the multiplexed detection of analytes at concentrations relevant to the monitoring of the quality of water resources.

The growing prevalence of chronic digestive disorders, such as inflammatory bowel disease, underscores the urgent need for innovative solutions that enable longitudinal monitoring of disease progression and treatment efficacy. Addressing this challenge, we present a novel microneedle-based sensor designed for rapid, point-of-care assessment of intestinal barrier integrity. Through transient application to the skin, the device samples intestinal fatty acid binding protein (IFABP) from systemic circulation, offering a minimally invasive alternative to conventional diagnostics. We demonstrate a versatile, affinity-based electrochemical sensing mechanism integrated into low-cost and clean room-free microneedles. The resulting device is validated in a biomimetic skin-like hydrogel in which it achieves good linearity, a limit of detection of 1.5 ng mL⁻¹ and highly specific response in a short assay format of one hour including the sampling phase. Furthermore, we validate the sensor's biocompatibility, penetration efficiency, and sensing capability in ex vivo human skin, establishing a critical foundation for future clinical applications. This breakthrough technology holds significant promise for transforming the management of gastrointestinal diseases through frequent, patient-friendly monitoring.

Accurate enumeration of CD4+ and CD8+ T lymphocytes is essential for HIV management, yet conventional flow cytometry remains largely inaccessible in resource-limited settings. Current point-of-care testing (POCT) approaches, including lateral flow assays and fluorescence-based imaging methods, offer improved accessibility but typically compromise accuracy and yield semi-quantitative results. Here, we present a magnetic-activated smartphone microflow cytometry (MACC) platform that enables rapid, highly accessible, and fully quantitative T lymphocyte counting at the POCT. MACC integrates microfluidic immunomagnetic cell separation with smartphone-based bright-field imaging, providing high-sensitivity, highly accessible analysis without requiring sophisticated laboratory equipment or fluorescent labels. A degassing-driven microfluidic pumping mechanism ensures stable microflow generation for reliable continuous analysis, while smartphone imaging enables clear differentiation of targeted lymphocytes from non-lymphocytes. The complete assay, including magnetic bead labeling, chip operation, hands-on procedures, and automated cell-counting analysis, is completed within 24 min. Validation with HIV-infected patient samples demonstrated strong concordance between MACC and conventional flow cytometry for CD4+ and CD8+ counts as well as CD4/CD8 ratio measurements, with minimal bias. By combining high accessibility, cost-effectiveness, and ease of operation, MACC represents a promising alternative to traditional methods, facilitating decentralized HIV monitoring and expanding diagnostic accessibility in resource-limited settings.

Applying CRISPR-based diagnostics to point-of-care pathogen detection remains challenging because of the multi-step and time-consuming sample preparation process. This study presents a low-cost, integrated valved microfluidic device that combines recombinase polymerase amplification (RPA), CRISPR signal amplification, and lateral flow readout for simultaneous nucleic acid detection. The core advantage of the platform lies in its ability to sequentially control the entire multi-step assay through simple valve operation, significantly minimizing user intervention. All key reagents, including the RPA mix, Cas12a/crRNA complex, and proteinase K lysis buffer, are pre-lyophilized, ensuring stability and ready-to-use functionality. The platform demonstrates a sensitivity of 20 copies/reaction for HPV16/18 plasmids and accurately genotypes HPV in lysates of cervical cancer cells within one hour, showing complete concordance with quantitative PCR results. This integrated device, achieving a user-friendly protocol and visual readout, provides a powerful tool for nucleic acid-based point-of-care testing and self-testing in resource-limited settings.