An innovative microfluidic platform for magnetic beads manipulation is introduced, consisting of novel microfabricated 3D magnetic devices positioned in a microfluidic chamber. Each magnetic device comprises of an embedded actuation micro-coil in various design versions, a ferromagnetic pillar, a magnetic backside plate and a sensing micro-coil. The various designs of the micro-coils enable efficient magnetic beads trapping and concentration in different patterns. The finite element analysis (FEA) results show a significant increase of the developed force on suspended magnetic beads when the magnetic pillar and backside plate were integrated into the device structure. These simulation results were confirmed experimentally by measuring the magnetic beads trapping ratios for the different designs and structures of the devices under continuous flow conditions. The trapping ratios and profiles were studied using beads counting, measuring the change of inductance with the sensing micro-coil and by image processing. The devices have efficiently demonstrated a controlled and localized magnetic beads trapping and concentration at small spatial locations for the first time. The new results shown in this study demonstrate the feasibility of efficiently using these original devices as key elements in complex bio-analysis systems.
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http://dx.doi.org/10.1016/j.bios.2005.08.006 | DOI Listing |
Anal Chem
January 2025
The School of Information Sciences and Technology, Northwest University, Xi'an 710127, P.R.China.
Digital fluorescence immunoassay (DFI) based on random dispersion magnetic beads (MBs) is one of the powerful methods for ultrasensitive determination of protein biomarkers. However, in the DFI, improving the limit of detection (LOD) is challenging since the ratio of signal-to-background and the speed of manual counting beads are low. Herein, we developed a deep-learning network (ATTBeadNet) by utilizing a new hybrid attention mechanism within a UNet3+ framework for accurately and fast counting the MBs and proposed a DFI using CdS quantum dots (QDs) with narrow peak and optical stability as reported at first time.
View Article and Find Full Text PDFVet Sci
January 2025
College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China.
(PCV2) is the main and primary causative agent of Postweaning Multisystemic Wasting Syndrome (PMWS). To date, immunoperoxidase monolayer assay (IPMA), indirect immunofluorescent assay (IFA), and enzyme linked immunosorbent assay (ELISA) are the most commonly diagnostic methods for detecting PCV2 antigens. However, these methods require specialized equipment and technical expertise and are suitable for laboratory use only.
View Article and Find Full Text PDFBiosensors (Basel)
December 2024
School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 102488, China.
Microbial contamination is an important factor threatening the safety of Chinese medicine preparations, and microfluidic detection methods have demonstrated excellent advantages in the application of rapid bacterial detection. In our study, a novel optical biosensor was developed for the rapid and sensitive detection of in traditional Chinese medicine on a microfluidic chip. Immune gold@platinum nanocatalysts (Au@PtNCs) were utilized for specific bacterial labeling, while magnetic nano-beads (MNBs) with a novel high-gradient magnetic field were employed for the specific capture of bacteria.
View Article and Find Full Text PDFBMC Med
January 2025
Shengli Clinical Medical College, Fujian Medical University, Fujian, Fuzhou, 350001, China.
Background: Esophageal squamous cell carcinoma (ESCC) is often diagnosed at an advanced stage due to the lack of non-invasive early detection tools, which significantly impacts patient prognosis. Given that glycosylation alterations especially high sialylation and fucosylation, frequently occur during cellular malignant transformation, but their roles are not elucidated. We examined alterations in disease-specific glycosylated extracellular vesicles (EVs)-derived miRNAs in the serum of ESCC patients, evaluating their utility as diagnostic biomarkers.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Chemical Engineering, University of Florida, Gainesville, FL 32611.
We describe a microfluidic device to extract DNA from a cell lysate, without the need for centrifuges, magnetic beads, or gels. Instead, separation is driven by transverse migration of DNA, which occurs when a polyelectrolyte solution flowing through a microfluidic channel is subjected to an electric field. The coupling of the weak shearing with the axial electric field is highly selective for long, flexible, charged molecules, of which DNA is the sole example in a typical cell lysate.
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