Lab on a Chip最新文献

Biohybrid implants are a promising development for cardiovascular disease treatment but suffer from problems like thrombogenesis and calcification. However, testing and validating biohybrid implants can be difficult and expensive due to material handling, fabrication methods and specialty medium components. The devices used to test potential samples can be large and expensive, requiring significant amounts of cell culture medium to operate. Additional, conventional static cell culture conditions do not accurately represent the vascular environment as shear and mechanical forces play key roles in the development of calcification. To address these challenges, a miniaturized, dual-channel flow chamber was designed and validated that allowed for real-time visualization of biohybrid calcification in a physiological environment. Computational fluid dynamics simulations were performed to determine the flow characteristics that generated physiological shear stress homogeneously across the sample surface. Micro particle tracking velocimetry measurements validated the simulated shear stresses near the sample surface. Two implant materials used for biohybrid construction, bovine pericardium and polycarbonate urethane, were inserted in the device and exposed to a flowing calcification medium for 14 days. Fluorescent fetuin-A was introduced into the calcification medium for real-time calcification monitoring. The two materials were compared with matched samples calcified in a large fatigue tester for 14 days. Our results showed similar material calcification for bovine pericardium and no calcification for polycarbonate urethane in the large fatigue tester and in our newly developed device. Biohybrid textile-reinforced fibrin-based scaffold populated with vascular smooth muscle cells started to calcify over 7 days in calcification medium. We conclude that this platform will provide novel insights into the origin and progression of pathological calcification and its potentially harmful health effects, which can occur as a result of tissue or metabolic abnormalities, disease, or implantation of certain biomaterials, by providing the ability to monitor the progression of calcification in biohybrid implants in real time, while also minimizing the cost and size of samples and reagents required for testing.

Three-dimensional cell culture provides a powerful framework for studying the growth of tissue in vitro. To account for biological variability, it is important to generate a large number of model tissues within well-controlled environments. In this context, droplet microfluidics has emerged as a promising tool for encapsulating cells in extracellular matrices with well-defined mechanical properties. However, its use in biology laboratories remains limited due to technical and biological challenges. In this work, we present a simple method for encapsulating mammalian cells in alginate gel microbeads using a commercial microfluidic chip. It relies on the formation of a double emulsion with an alginate core and an oleic acid shell allowing the diffusion of calcium to achieve homogeneous crosslinking of the alginate. Encapsulated cells are viable and proliferate to form multicellular spheroids that grow under confinement within the elastic alginate hydrogel. This method avoids the need for custom chip engineering, which makes it accessible for use in standard biology laboratories. Altogether, this method offers a practical tool for investigating tissue growth in controlled microenvironments with high reproducibility.

Imaging flow cytometry demands a careful balance between spatial resolution, spectral multiplexing, throughput, and system complexity. Here, we present LFC-plus, a next-generation light-field cytometry platform that enables multiparametric, simultaneous multi-color, and volumetric single-cell analysis. The system integrates model-based image restoration, custom-designed light-field optics, and spectral aperture partitioning, achieving subcellular resolution in all three dimensions, a near-millimeter-scale imaging cross-section, and an analytical imaging throughput of nearly 200 000 cells per second. We validate its performance across diverse biological applications, including chemotherapy response profiling, PEG-mediated cell fusion, and stiffness-based flow migration. These results establish LFC-plus as a robust and scalable platform for high-content volumetric cytometry, with broad implications spanning fundamental biology and translational diagnostics.

Wound care remains a significant global challenge, where delayed healing can lead to severe complications. While aerosol-based drug delivery offers a promising alternative to conventional treatments, its efficacy is often compromised by inconsistent atomization and poor distribution. Surface acoustic wave (SAW)-driven atomization can generate uniform micro-droplets but is fundamentally limited by the low propagation velocity of conventional surface mists and a fixed, unalterable spray direction. Here, we introduce a SAW-assisted swing-angle spray (SAW-SAS) strategy that overcomes these limitations. This method achieves effective, directionally adjustable spraying using only traveling SAWs, achieving targeted deposition while eliminating the need for external accelerating fields, and thereby transcending the conventional restriction of SAW atomization to the 22° Rayleigh angle. SAW-SAS produces a highly focused spray, enabling precise control over the deposition area and droplet size. We demonstrate that the swing-angle mechanism is governed by modulating the input frequency relative to the device's resonant frequency. This modulation alters the multi-modal acoustic waves in the device's edge region, which are shown by 2D simulations, shifts the internal acoustic streaming within the parent droplet and repositions the unstable oscillation point of the air–liquid interface. Deposition experiments confirmed that SAW-SAS provides excellent surface coverage with consistent droplet sizes across a range of spray angles. Furthermore, in a murine model, SAW-SAS-based drug delivery significantly accelerated skin wound healing. By using a narrow spray angle for deep drug penetration and a wider angle for broad surface coverage, our approach enables tailored drug delivery that matches the dosage to the wound's topography, thereby minimizing the risk of adverse effects from excessive drug application.

Sheathless prefocusing of particles and cells is a critical preparatory step in biomedical assays, while focusing performance directly impacts processing throughput and detection sensitivity. Although standing surface acoustic wave (SSAW)-based acoustofluidics has been widely used across nano- and micro-scale applications, reliance on sheath flow remains a major constraint. Here, we introduce an SU-8/PDMS hybrid microchannel fabricated through in situ injection and photopolymerization that eliminates microchannel anechoic corners by augmenting acoustic energy transmission via hybrid sidewalls. The influence of sidewall dimensions on acoustic field distribution was systematically investigated using a two-dimensional finite element model, guiding the design of a cascaded hybrid microchannel that achieved over tenfold focusing of 2.5 and 5 μm polystyrene (PS) beads without sheath flow. Comparable performance was demonstrated with human promyelocytic leukaemia (HL-60) and human umbilical vein endothelial cells (HUVECs) at processing rates up to 3 × 10⁴ cells per min, confirming broad biological applicability. The modular and fabrication-friendly architecture presents a versatile sheathless prefocusing solution for integrated acoustofluidic systems.

Extraction and purification of mRNA are critical steps for diverse molecular biological applications, including gene expression analyses, vaccine development, and genomic assays. To enhance mRNA extraction efficiency, we designed an integrated microfluidic chip capable of isolating in vitro transcribed (IVT) mRNAs (up to 93%) via probe-coated magnetic beads without the need for high-speed centrifugation, organic solvents, or cooling conditions. mRNA-specific probe-coated magnetic beads were employed, thereby automating the entire workflow, including IVT, DNase treatment, mRNA extraction, and reverse transcription (RT) could all be performed on-chip. This advancement is particularly significant for on-chip transcription–translation coupled with puromycin linker association (TRAP) display screening applications. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis confirmed the device's ability to selectively capture mRNA with a high capture efficiency of 93% within 15 minutes and 48% of thermal release efficiency after 10 minutes at 95 °C. By incorporating this optimized approach into a fully automated lab-on-chip system, puromycin-linked mRNAs could be directly used for peptide screening of kinesin family member 2C (KIF2C), a protein overexpressed in aggressive cancers.

The concept of logical neural networks, proposed by McCulloch and Pitts, along with Hebb's postulate of learning—specifically, spike-timing-dependent plasticity (STDP), has had a substantial influence on the development of brain-inspired computing research. To investigate how these concepts affect the computational principles used by real neurons, 4 × 4 crossbar neuronal networks were constructed on multi-electrode arrays (MEAs) with PDMS microfluidic channels, allowing for precise control of neural connectivity. Spatiotemporal recording of neural activity using MEAs revealed that threshold voltages and response times varied according to pre-post spike timing, consistent with established STDP mechanisms. Potentiated states exhibited retention times exceeding 6 h. We implemented reconfigurable logic gates through synaptic plasticity—an initial AND gate transitioned to an OR gate upon potentiation, while subsequent depression reversed this change. These findings confirm that reconfigurable logic-in memory can be achieved in crossbar neuronal networks through STDP learning, offering insights into neuromorphic research.