High-Density Microfluidic Particle-Cluster-Array Device for Parallel and Dynamic Study of Interaction between Engineered Particles

Highly Flexible Deep-Learning-Based Automatic Analysis for Graphically Encoded Hydrogel Microparticles

Graphically encoded hydrogel microparticle (HMP)-based bioassay is a diagnostic tool characterized by exceptional multiplex detectability and robust sensitivity and specificity. Specifically, deep learning enables highly fast and accurate analyses of HMPs with diverse graphical codes. However, previous related studies have found the use of plain particles as data to be disadvantageous for accurate analyses of HMPs loaded with functional nanomaterials. Furthermore, the manual data annotation method used in existing approaches is highly labor-intensive and time-consuming. In this study, we present an efficient deep-learning-based analysis of encoded HMPs with diverse graphical codes and functional nanomaterials, utilizing the auto-annotation and synthetic data mixing methods for model training. The auto-annotation enhanced the throughput of dataset preparation up to 0.11 s/image. Using synthetic data mixing, a mean average precision of 0.88 was achieved in the analysis of encoded HMPs with magnetic nanoparticles, representing an approximately twofold improvement over the standard method. To evaluate the practical applicability of the proposed automatic analysis strategy, a single-image analysis was performed after the triplex immunoassay for the preeclampsia-related protein biomarkers. Finally, we accomplished a processing throughput of 0.353 s per sample for analyzing the result image.

Microfluidics-Based Single-Cell Research for Intercellular Interaction

Intercellular interaction between cell-cell and cell-ECM is critical to numerous biology and medical studies, such as stem cell differentiation, immunotherapy and tissue engineering. Traditional methods employed for delving into intercellular interaction are limited by expensive equipment and sophisticated procedures. Microfluidics technique is considered as one of the powerful measures capable of precisely capturing and manipulating cells and achieving low reagent consumption and high throughput with decidedly integrated functional components. Over the past few years, microfluidics-based systems for intercellular interaction study at a single-cell level have become frequently adopted. This review focuses on microfluidic single-cell studies for intercellular interaction in a 2D or 3D environment with a variety of cell manipulating techniques and applications. The challenges to be overcome are highlighted.

Microfluidic platform for selective microparticle parking and paired particle isolation in droplet arrays

Immobilizing microscale objects (e.g., cells, spheroids, and microparticles) in arrays for direct observation and analysis is a critical step of many biological and chemical assays; however, existing techniques are often limited in their ability to precisely capture, arrange, isolate, and recollect objects of interest. In this work, we present a microfluidic platform that selectively parks microparticles in hydrodynamic traps based on particle physical characteristics (size, stiffness, and internal structure). We present an accompanying scaling analysis for the particle parking process to enable rational design of microfluidic traps and selection of operating conditions for successful parking of desired particles with specific size and elastic modulus. Our platform also enables parking of encoded particle pairs in defined spatial arrangements and subsequent isolation of these pairs in aqueous droplets, creating distinct microenvironments with no cross-contamination. In addition, we demonstrate the ability to recollect objects of interest (i.e., one particle from each pair) after observation within the channel. This integrated device is ideal for multiplexed assays or microenvironment fabrication for controlled biological studies.

Real-time two-photon lithography in controlled flow to create a single-microparticle array and particle-cluster array for optofluidic imaging

Microarray technology provides an excellent platform for biomedical and biochemical research including basic scientific studies, drug discovery, and diagnostics. Here, we develop a novel method referred to as real-time two-photon lithography in a controlled flow in which femtosecond laser two-photon lithography is performed in situ in the sequential mode stopping and flowing the flow of liquid resin containing microparticles to achieve 100% trapping on a one-bead-to-one-trap basis. Polydisperse particles can be all trapped to form a desired array by freely designing trap structures, resulting in an unprecedentedly high capture efficiency of ∼100%. No persistent pressure is needed after trapping which reduces the complexity of the system. In addition, trapping of particle-cluster arrays with a controlled number of particles is also achieved via this method. The trapped particles inside the microchip are successfully applied as microlenses for high quality imaging. The present technology marks an essential step towards a versatile platform for the integration of bead-based assays and paves the way for developing innovative microfluidics, optofluidics, micro-optics and single-cell analysis devices.