Microfluidic-Assisted Caenorhabditis elegans Sorting: Current Status and Future Prospects

Electromagnetohydrodynamic flow of fractional Maxwell fluids through a stenosed artery: Caputo fractional derivatives approach

This study investigates the electromagnetohydrodynamic (EMHD) flow of fractional Maxwell fluids through a stenosed artery, accounting for body acceleration. The flow is considered highly pulsatile. The mathematical model is formulated using differential forms of the conservation of mass and momentum. The governing equations are nondimensionalized and simplified by assuming mild stenosis. Through the application of the Caputo fractional derivative, the classical problem is transformed into its fractional equivalent. Solutions are derived using Laplace and finite Hankel transformations, with the inverse Laplace transform applied afterward. The findings show that blood velocity, flow rate, and shear stress fluctuate continuously over time due to the pulsatile flow and the effects of body acceleration.

AI-based prediction of flow dynamics of blood blended with gold and maghemite nanoparticles in an electromagnetic microchannel under abruptly changes in pressure gradient

In cardiovascular research, electromagnetic fields (EMFs) induced by Riga plates are applied to study and potentially manipulate blood flow dynamics, offering insights for therapies against arterial plaque deposition and for understanding varied blood flow behaviors. This research focuses on predicting the flow patterns of blood infused with gold and maghemite nanoparticles (gold-maghemite/blood) inside an EM microchannel under these electromagnetic influences and abruptly change in pressure gradient. The study models these flows by considering radiation heat emission and Darcy drag forces within porous media. Mathematical representation involves time-variant partial differential equations, resolved through Laplace transform (LT) to yield compact-form expressions for the model variables. The outcomes, including shear stress (SS) and rate of heat transfer (RHT) across the microchannel, are analyzed and displayed graphically, highlighting the effects of modified Hartmann number and electrode width on these parameters. Hybrid nano-blood (HNB) and nano-blood (NB) exhibit distinct thermal characteristics, with HNB transferring more heat within the blood flow. These study implements a cutting-edge AI-powered approach for high-fidelity evaluation of critical flow parameters, achieving unprecedented prediction accuracy. Validation results confirm the algorithm's excellence, with SS predictions reaching 99.552% (testing) and 97.019% (cross-validation) accuracy, while RHT predictions show 100% testing accuracy and 97.987% cross-validation reliability. This convergence of nanotechnology with advanced machine learning paves the way for transformative clinical applications that could redefine standards of care in surgical oncology, interventional cardiology, and therapeutic radiology. This model underpins potential applications such as controlled drug release and magnetic fluid hyperthermia, enhancing procedures like cardiopulmonary bypass, vascular surgery, and diagnostic imaging.

Development of a size-separation technique to isolate Caenorhabditis elegans embryos using mesh filters

The free-living nematode Caenorhabditis elegans has been routinely used to study gene functions, genetic interactions, and conserved signaling pathways. Most experiments require that the animals are synchronized to be at the same specific developmental stage. Bleach synchronization is traditionally used to obtain a population of staged embryos, but the method can have harmful effects on the embryos. The physical separation of differently sized animals is preferred but often difficult to perform because some developmental stages are the same sizes as others. Microfluidic device filters have been used as alternatives, but they are expensive and require customization to scale up the preparation of staged animals. Here, we present a protocol for the synchronization of embryos using mesh filters. Using filtration, we obtained a higher yield of embryos per plate than using the standard bleach synchronization protocol and at a scale beyond microfluidic devices. Importantly, filtration has no deleterious effects on downstream larval development assays. In conclusion, we have exploited the differences in the sizes of C. elegans developmental stages to isolate embryo cultures suitable for use in high-throughput assays.

Genetic Architecture of Hock Joint Bumps in Pigs: Insights from ROH and GWAS Analyses

The genetic mechanisms underlying the formation of defects, such as bumps and growths on the hock joints in pigs, remain poorly understood. Therefore, the aim of this study was to investigate the relationship between runs of homozygosity (ROH) and the formation of hock joint bumps, with the goal of identifying associated SNPs and candidate genes involved in these defects. The study was conducted on a population of Large White breed pigs (n = 568) using runs of homozygosity (ROH) analysis and genome-wide association studies (GWAS). The results suggested that the predisposition to hock joint bumps in pigs may have arisen due to recent selective breeding pressure. Using GWAS, 27 SNPs were identified at the suggestive significance level, with one SNP (rs325478346) reaching genome-wide significance. These markers are localized in genes associated with various biological processes, including lipid metabolism (VIPR2 and CFTR), inflammatory processes (MTURN and ADCY2), connective tissue structural integrity (COL27A1), muscle regeneration (PAMR1), and ion exchange and cellular homeostasis (KCNIP4 and NALCN), as well as regulation of cell growth, extracellular matrix remodeling, and fibroblast differentiation (CEP120 and SCUBE3). Further research utilizing omics technologies will provide deeper insights into the pathogenesis of hock joint bumps and contribute to the development of strategies for the prevention and potential treatment of this defect.

Microfluidic synthesis of stable and uniform curcumin-loaded solid lipid nanoparticles with high encapsulation efficiency

Solid Lipid Nanoparticles (SLNs) are a suitable method for encapsulating poorly soluble curcumin by dispersing the drug in solid lipids. However, the commonly used bulk method has disadvantages such as low reproducibility and encapsulation efficiency. To overcome these issues, we used a microfluidic machine to achieve more uniform mixing, resulting in an encapsulation efficiency of over 60%. The synthesized SLNs released over approximately six days and demonstrated colloidal stability for two weeks without aggregation. To synthesize the SLNs, we equipped the microfluidic machine with a temperature controller, which enabled the large-scale production of more reproducible and stable SLNs compared to those synthesized using the existing microfluidic machines.

Continuous FACS sorting of double emulsion picoreactors with a 3D printed vertical mixer

High-throughput screening and directed evolution using microfluidic picoreactors have produced high-activity enzymes. In this approach, a substrate is co-encapsulated with a candidate enzyme and individual picoreactors are sorted based on an activity reporter. While many approaches use water-in-oil droplets (single emulsions) for fluorescence-activated droplet sorting (FADS) on custom-fabricated microfluidic devices that require integrated optics and electronics, recent approaches have lowered the engineering barriers to adoption by using simple microfluidic droplet generators to produce water-in-oil-in-water droplets (double emulsion picoreactors, DEs) that can be sorted with commercial FACS (fluorescence-activated cell sorting). Despite the simplified engineering requirements, high variability in loading rates and low yield during loading are barriers to efficient DE FACS sorting. Here, we optimized surfactants to enhance DE stability and demonstrated that a 3D-printed corkscrew on the sample line acts as a vertical mixer to enable more continuous loading. With these optimized loading conditions, we analyzed 1.17 million DEs in four 10-minute sorting rounds with a mean frequency of 480 Hz (390 Hz including sample exchanges); in a mock sort of 10% fluorescent DEs, we achieved 89.2±1.1% accuracy and 78±0.9% recovery with our optimized loading protocol. Overall, improved ease-of-use and throughput for FACS sortable DEs should expand the accessibility of directed evolution in controlled in vitro environments.

Design and developing a robot-assisted cell batch microinjection system for zebrafish embryo

The microinjection of Zebrafish embryos is significant to life science and biomedical research. In this article, a novel automated system is developed for cell microinjection. A sophisticated microfluidic chip is designed to transport, hold, and inject cells continuously. For the first time, a microinjector with microforce perception is proposed and integrated within the enclosed microfluidic chip to judge whether cells have been successfully punctured. The deep learning model is employed to detect the yolk center of zebrafish embryos and locate the position of the injection needle within the yolk, which enables enhancing the precision of cell injection. A prototype is fabricated to achieve automatic batch microinjection. Experimental results demonstrated that the injection efficiency is about 20 seconds per cell. Cell puncture success rate and cell survival rate are 100% and 84%, respectively. Compared to manual operation, this proposed system improves cell operation efficiency and cell survival rate. The proposed microinjection system has the potential to greatly reduce the workload of the experimenters and shorten the relevant study period.

Airborne Acoustic Vortex End Effector-based Contactless, Multi-mode, Programmable Control of Object Surfing

Tweezers based on optical, electric, magnetic, and acoustic fields have shown great potential for contactless object manipulation. However, current tweezers designed for manipulating millimeter-sized objects such as droplets, particles, and small animals, exhibit limitations in translation resolution, range, and path complexity. Here, we introduce a novel acoustic vortex tweezers system, which leverages a unique airborne acoustic vortex end effector integrated with a three degree-of-freedom (DoF) linear motion stage, for enabling contactless, multi-mode, programmable manipulation of millimeter-sized objects. The acoustic vortex end effector utilizes a cascaded circular acoustic array, which is portable and battery-powered, to generate an acoustic vortex with a ring-shaped energy pattern. The vortex applies acoustic radiation forces to trap and spin an object at its center, simultaneously protecting this object by repelling other materials away with its high-energy ring. Moreover, our vortex tweezers system facilitates contactless, multi-mode, programmable object surfing, as demonstrated in experiments involving trapping, repelling, and spinning particles, translating particles along complex paths, guiding particles around barriers, translating and rotating droplets containing zebrafish larvae, and merging droplets. With these capabilities, we anticipate that our tweezers system will become a valuable tool for the automated, contactless handling of droplets, particles, and bio-samples in biomedical and biochemical research.

Scalable Electrophysiology of Millimeter-Scale Animals with Electrode Devices

Millimeter-scale animals such as Caenorhabditis elegans, Drosophila larvae, zebrafish, and bees serve as powerful model organisms in the fields of neurobiology and neuroethology. Various methods exist for recording large-scale electrophysiological signals from these animals. Existing approaches often lack, however, real-time, uninterrupted investigations due to their rigid constructs, geometric constraints, and mechanical mismatch in integration with soft organisms. The recent research establishes the foundations for 3-dimensional flexible bioelectronic interfaces that incorporate microfabricated components and nanoelectronic function with adjustable mechanical properties and multidimensional variability, offering unique capabilities for chronic, stable interrogation and stimulation of millimeter-scale animals and miniature tissue constructs. This review summarizes the most advanced technologies for electrophysiological studies, based on methods of 3-dimensional flexible bioelectronics. A concluding section addresses the challenges of these devices in achieving freestanding, robust, and multifunctional biointerfaces.

Deep Learning for Microfluidic-Assisted Caenorhabditis elegans Multi-Parameter Identification Using YOLOv7

The Caenorhabditis elegans (C. elegans) is an ideal model organism for studying human diseases and genetics due to its transparency and suitability for optical imaging. However, manually sorting a large population of C. elegans for experiments is tedious and inefficient. The microfluidic-assisted C. elegans sorting chip is considered a promising platform to address this issue due to its automation and ease of operation. Nevertheless, automated C. elegans sorting with multiple parameters requires efficient identification technology due to the different research demands for worm phenotypes. To improve the efficiency and accuracy of multi-parameter sorting, we developed a deep learning model using You Only Look Once (YOLO)v7 to detect and recognize C. elegans automatically. We used a dataset of 3931 annotated worms in microfluidic chips from various studies. Our model showed higher precision in automated C. elegans identification than YOLOv5 and Faster R-CNN, achieving a mean average precision (mAP) at a 0.5 intersection over a union (mAP@0.5) threshold of 99.56%. Additionally, our model demonstrated good generalization ability, achieving an mAP@0.5 of 94.21% on an external validation set. Our model can efficiently and accurately identify and calculate multiple phenotypes of worms, including size, movement speed, and fluorescence. The multi-parameter identification model can improve sorting efficiency and potentially promote the development of automated and integrated microfluidic platforms.

Microfluidic Study of Enhanced Oil Recovery during Flooding with Polyacrylamide Polymer Solutions

A series of experiments have been carried out on the flooding of microfluidic chips simulating a homogeneous porous structure with various displacement fluids. Water and polyacrylamide polymer solutions were used as displacement fluids. Three different polyacrylamides with different properties are considered. The results of a microfluidic study of polymer flooding showed that the displacement efficiency increases significantly with increasing polymer concentration. Thus, when using a 0.1% polymer solution of polyacrylamide grade 2540, a 23% increase in the oil displacement efficiency was obtained compared to water. The study of the effect of various polymers on the efficiency of oil displacement showed that the maximum efficiency of oil displacement, other things being equal, can be achieved using polyacrylamide grade 2540, which has the highest charge density among those considered. Thus, when using polymer 2515 with a charge density of 10%, the oil displacement efficiency increased by 12.5% compared to water, while when using polymer 2540 with a charge density of 30%, the oil displacement efficiency increased by 23.6%.