Lab on a Chip最新文献

Bulk acoustic wave devices commonly use thickness modes of piezoelectric plates to generate standing waves in microfluidic cavities, typically at 2 MHz and above, with corresponding wavelengths well below the millimeter scale. However, handling larger mesoscopic objects-such as organoids and small model organisms, including nematodes-requires millimeter-scale fluidic structures. Single-node alignment in such cavities demands half-wavelength fields and thus sub-megahertz actuation. Conventional sub-megahertz operation requires thicker piezoelectric plates, resulting in bulky designs or requiring plate thicknesses that are not readily available commercially. Here, we demonstrate a practical yet elegant alternative based on a low-order lateral extensional mode of the transducer plate. Compared with thickness-mode devices of identical footprint, the approach lowers the operating frequency approximately fourfold and increases the channel cross section sixteenfold. Unlike typical Lamb-wave devices based on multiwavelength propagation at several megahertz and above, the present approach uses a low-order standing S₀ Lamb mode. The numerically optimized devices operate at approximately 540 kHz and achieve rapid particle focusing in millimeter-wide channels, while vibrometry confirms the predicted vibration patterns and admittance measurements show that the lateral resonance is well preserved upon chip loading, with only a small, predictable shift in resonance frequency. The present study focuses on modal characterization and particle-focusing validation. Practical limitations include heating at high actuation voltages and the finite lifetime of the liquid acoustic coupling layer.

Imaging flow cytometry (IFC) combines microscopic techniques and flow cytometry, enabling high-throughput, population-scale single-cell analysis with rich spatial detail and high molecular specificity. To date, most established IFC platforms are fundamentally built around 2D imaging, which is inherently limited in its ability to capture the complex 3D morphology, intracellular organization, and spatially distributed molecular features of single cells under flow. Driven by the growing demand for volumetric cellular information, IFC has progressively evolved from 2D imaging toward 3D imaging flow cytometry through a variety of optical and computational strategies. Existing 3D IFC approaches typically fall into scanning-based and non-scanning modalities, depending on whether volumetric information is assembled through sequential or parallel acquisition, with each paradigm offering complementary strengths in 3D imaging performance and cytometric throughput. Here, we systematically compare the underlying principles and performance characteristics of the most representative scanning-based and non-scanning 3D IFC technologies and discuss current challenges and future opportunities to advance volumetric cytometric analysis in biomedical and translational research.

Engineering three-dimensional cellular systems with controlled size, matrix composition and cellular organization is central to disease modelling, drug evaluation and regenerative medicine. In this context, cell-laden hydrogel microspheres have emerged as a platform for constructing microscale living units. Their structure facilitates local cell-matrix interactions and cell-cell communication, while the hydrogel phase provides a tunable microenvironment for cell culture and function. Droplet microfluidics offers a powerful route to produce these microspheres with defined size, composition, architecture and cellular input, allowing fabrication parameters to be linked directly with biological outcomes. In this review, we focus on how droplet microfluidics, hydrogel matrix design and cellular organization converge to transform cell encapsulation into the construction of functional 3D cellular units. We outline the principles of microsphere fabrication, including droplet generation, gelation and post-generation recovery, and discuss how hydrogel matrices regulate processability, bioactivity and reproducibility. We then examine how cell loading, spatial architecture and organoid-centered organization determine microsphere function. Finally, we discuss applications in bioanalysis, drug testing, therapeutic delivery and tissue assembly, and highlight key challenges in cytocompatible processing, recovery, reproducibility, standardization and functional validation. This review aims to provide design principles for transforming cell encapsulation into interpretable and deployable microscale living systems.

Inertial microfluidics provides a label-free strategy for isolating circulating tumor cells (CTCs) from blood by exploiting size-dependent lateral migration in microchannels. However, straight-channel devices are often optimized using the final equilibrium position, even though target-cell loss can arise from incomplete or poorly reproducible migration before outlet collection. Here, we show that heteroclinic orbit engagement provides a predictive design criterion for improving CTC scale separation in a rectangular co-flow inertial microchannel. A computational model predicted size-dependent heteroclinic orbits and lateral migration velocities, which were experimentally validated using beads under controlled inlet flow-split conditions. Increasing buffer confinement shifted the sample-buffer interface closer to the sidewall, promoted earlier orbit engagement, improved agreement between measured and simulated velocity profiles, and reduced upstream trajectory variability. Larger CTC scale particles engaged their orbits earlier and migrated more reproducibly, while smaller white blood cell (WBC) scale particles remained laterally displaced from the larger particle focusing region. Biological validation with PANC1 and A549 cells showed that the 1 : 6 : 1 flow-split configuration increased separation efficiency to 99.9 ± 0.2% for PANC1 and maintained high separation efficiency of 99.2 ± 0.9% for A549 cells, although its effect on total recovery was cell line dependent. In an intraductal papillary mucinous neoplasm (IPMN) patient sample, representing a premalignant pancreatic lesion that may progress to invasive pancreatic ductal adenocarcinoma (PDAC), CTC target outlet partitioning was 67% under 1 : 1 : 1 and 100% under 1 : 6 : 1, within the limits of the detected cell numbers. These results establish orbit engagement as a mechanistic design principle for improving clinically relevant CTC enrichment without changing device geometry, total flow rate, or labeling strategy.

Timely and accurate nucleic acid extraction is a critical bottleneck in point-of-care (POC) molecular diagnostics, particularly for low-abundance cell-free nucleic acids (DNA, RNA, miRNA) in plasma. We present a fully finger-actuated microfluidic device for power-free, pipette-free, nucleic acid extraction. The prototype device integrates finger-actuated valves, pump and blister reagent storage, enabling a complete, intuitive, "sample-to-eluate" workflow, including lysis, binding, washing and elution via manual actuation in approximately 35 minutes. The device operation was benchmarked against a commercial magnetic bead-based manual benchtop and an automated robotic workflow. In DNA-spiked aqueous samples (5-20 ng mL^-1), the device demonstrated recoveries of 84.6%, against 90.7% on the bench. Optimisation of magnetic bead volume identified 50 μL as the threshold for maximal recovery while minimising reagent consumption. Recovery from human pooled plasma samples were found to be on average 18, 62, and 552% higher than that obtained with the control bench extraction on initial sample volumes of 100, 75 and 50 μL, respectively. Coefficient of variation (CV%) for all techniques remained within reported laboratory ranges (20-80%). The device's clinical utility was piloted using patient samples positive for cytomegalovirus (CMV), monkeypox virus (MPXV) or chikungunya (CHIKV). The device achieved successful qPCR amplification for all targets, with viral DNA Cq values within as little as 0.3 cycles of the standard protocol. This instrument-free, manual circulating nucleic acid extraction tool could help bridge the gap between lateral flow based nucleic acid amplification technologies and real-world decentralised diagnostics, offering a scalable solution for infectious disease management in resource-limited settings.

An immune-competent, metabolically active gut-liver microphysiological platform (iGLoC) was engineered to investigate the pharmacokinetics, metabolism, hepatotoxicity, and drug-drug interaction (DDI) liabilities of the oral CDK4/6 inhibitor abemaciclib. The system integrates a mucus-secreting Caco-2/HT-29 intestinal epithelium co-cultured with THP-1-derived macrophages and 3D HepG2 spheroids in interconnected PMMA/PDMS microfluidic chips linked by a controlled-flow bridging channel. Intestinal barrier morphology, tight-junction integrity, transepithelial electrical resistance, P-glycoprotein transport, and paracellular permeability were functionally validated, while hepatic spheroids exhibited stable albumin and urea secretion and pharmacologically inducible CYP3A4 activity relative to 2D HepG2 monolayers, while remaining less CYP3A4-competent than primary hepatocytes. Following apical dosing with abemaciclib, serial sampling from apical, basolateral, and hepatic chambers combined with a validated UPLC-MS/MS assay enabled time-resolved quantification of parent drug and major metabolites (M2, M20). The platform reproduced an oral-like disposition profile characterized by luminal depletion, a transient basolateral peak, and delayed hepatic appearance, along with formation of clinically relevant metabolites. Pre-treatment with rifampicin (CYP3A4/P-gp inducer) or clarithromycin (CYP3A4/P-gp inhibitor) and induction of colitis-like injury with dextran sulfate sodium generated distinct, mechanistically consistent alterations in intestinal permeability, metabolite output, and hepatic exposure that mirrored reported clinical DDIs and inflammation-associated variability. Abemaciclib also elicited concentration-dependent hepatocellular injury and modulation of gut-immune cytokine responses at clinically relevant levels. iGLoC innovates through immune-competent gut-liver integration under flow, quantitative clinical PK validation for abemaciclib, and mechanistic resolution of CYP3A4/P-gp DDIs and inflammation effects. Collectively, these data demonstrate that iGLoC represents a human-relevant organ-on-a-chip platform capable of evaluating oral bioavailability, first-pass metabolism, metabolite formation, hepatotoxicity, and drug interaction potential. The system shows promise for preclinical assessment of small-molecule therapeutics, including those used in precision oncology applications.

Label-free tracking of adherent cell migration could enable important insights into biological processes such as tissue repair, inflammatory response, or cancer progression. Nevertheless, visualizing unlabeled animal cells using optical microscopy remains challenging due to low contrast as well as frequent changes in cell shape and number. A promising alternative uses electrical capacitance measurements, which are sensitive to cell adhesion to electrode surfaces. However, prior examples often utilized electrodes with areas larger than single cells, resulting in averaged readouts over multiple cells. Here, we demonstrate label-free, live-cell tracking using a capacitance sensor array with more than 1 million pixels on a 10 micron pitch across an area larger than 1 square centimeter. We show that single cell morphology can be clearly segmented and used to reconstruct migration and proliferation dynamics using optical flow. We further track the spreading of multicellular spheroids, revealing fast-moving peripheral regions led by a collective leader cell "front". Finally, we demonstrate label-free imaging of millimeter-scale honeycomb-shaped tissues without the multi-image stitching often required for conventional microscopy. We utilize mutual capacitance measurements with electrically-programmable electrode spacing to map topographical features of these engineered tissues. Overall, CMOS capacitance imaging arrays enable label-free imaging spanning from single cells to large tissues, in a portable and scalable format for settings where optical microscopy may be difficult to access.