Biomedical Microdevices最新文献

The urgent need for adenosine triphosphate (ATP) detection spans various fields, particularly in biology and medicine. Developing a simple, quick, label-free, and highly sensitive biosensor for ATP detection is crucial. In this study, we created a label-free biosensor using a field-effect device, specifically an electrolyte-insulator-semiconductor (EIS) sensor, which was functionalized with aptamer and graphene. We prepared a nanocomplex by combining graphene with bovine serum albumin (BSA) in PBS and subjecting it to ultrasonication. This Graphene/BSA mixture was then combined with 70% glutaraldehyde to form the Graphene/BSA/GA nanocomplex. The successful modification of the EIS biosensor surface with Graphene/BSA/GA and aptamer immobilization was confirmed using atomic force microscopy (AFM), which indicated successful molecule attachment through surface roughness. Electrochemical characterization revealed that the biosensor is sensitive to ATP concentrations ranging from 0.1 nM to 100 nM, with a detection limit as low as 0.32 nM. Statistical analysis demonstrated the biosensor’s high sensitivity and specificity for ATP. Furthermore, the biosensor maintained stable performance for ATP detection over a period of 5 days. This sensing approach effectively detected ATP with outstanding performance, showing significant potential for advancing label-free ATP detection technologies.

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The accurate selection of living from dead pathogenic cells is crucial as exemplified in the context of detecting Legionella bacteria, which can be present in various water facilities and pose a threat to public health by causing severe respiratory problems. Traditional methods for Legionella detection, such as cultivation, are time-consuming, taking several days to yield valid results. Additionally, widely used bioanalytical methods like PCR lack the ability to distinguish between living and dead cells, leading to the potential for false-positive results. While dielectrophoresis has been proposed as a promising method for separating living and dead cells, our study contrasts with existing literature, revealing that the separation process and parameter characterization are non-trivial. In response to this challenge, our work introduces a novel, systematic approach of automated video analysis capable of quantifying the dielectrophoretic response of cells. By assigning a response coefficient to the dielectrophoretic effect at different conditions, our method identifies a narrow window for successful cell selection of viable Legionella cells from the non-pathogenic species L. parisiensis utilizing a microfluidic flow cell with top–bottom electrodes. These findings serve as a crucial pre-step in Legionella sensing, demonstrating applicability in experiments focused on the most relevant pathogenic species, L. pneumophila. Moreover, our method can be transferred to other cell types for quantitative detection of the dielectrophoretic response and identify optimal separation parameters.

Screening the amount of DNA closely related to early diagnosis of diseases or decoding information in target DNA sequences for biological medicine, infectious identification, or forensic analysis are highly essential in our daily life. This review provides clear understanding of nanostructured sensors (i.e., functionalized electrode-based sensors and nanopores) working for electrochemical assessment of DNA, along with their recent advances and unaddressed issues. Crucial constituents for sensor functionalization, electrochemical techniques, and electrodes, used in functionalized electrode-based sensors are briefly introduced, followed by analysis of using this type of sensors for DNA determination and the comparison of performances such as dynamic ranges and detection limits with other similar works. Subsequently, nanopore sensors including porin-based and solid-state nanopores applied for DNA sequencing are the other interests of discussion in the review. Beyond the achievement of high-resolution DNA sequencing based on porins coupled with enzymatic components, commonly used methods to solid-state nanopore creation, practical use of solid-state nanopores in DNA analysis, and computational modeling for nucleobase pore-threading simulation are depicted in more detail. Finally, conclusions in relation to recent advances and future developments are described. This work offers a powerful guideline for electrochemical assessment of DNA using either functionalized electrode-based sensors or nanopores, enabling scientific groups to have an entire picture upon electrochemical nanodevices used for DNA characterization.

In this research, we created a paper-based electrochemical immunosensor for detecting Pasteurella multocida antigen (Pm-Ag). Bacteria were obtained from a buffalo nasal swab, and the antigen was prepared and then injected into rabbits to induce a highly specific antibody (Pm-Ab). We created a carbon-based paper electrode chip using a screen-printing method, followed by coating with zinc oxide-nanoflowers (ZnO-NFs). The coating improved the sensor’s sensitivity due to the fact that zinc oxide- nanoflowers has remarkable physiochemical properties which enable electron transfer. Characterization of nanomaterial was conducted using UV-Vis spectroscopy, scanning electron microscopy (SEM), and energy dispersive X-rays (EDX). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used in electrochemical characterization. The developed platform demonstrated effective detection of Pm-Ag across concentrations from 0.9 to 6.4 µg/mL, achieving a limit of detection (LOD) as low as 0.9 µg/mL. These findings support the potential application of our sensor for detecting animal pathogens in a cost-effective, straightforward, and highly sensitive manner using a paper-based electrode chip.

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Extracellular vesicles (EVs) are nanosized particles secreted by most cells for information transmission, which affects the microenvironment. EVs are known to follow the characteristics and conditions of their mother cells and have attracted considerable attention for disease diagnosis and therapeutic effects. In particular, mesenchymal stem cell (MSC)-derived EVs have shown potential for facilitating regenerative wound healing, modulating immune responses, and inhibiting inflammatory diseases. However, previous isolation methods demonstrated limited EV yield, purity, and filter capacity. Here, we report a two-step tangential flow filtration (TFF) system using track-etched membranes with uniform cylindrical nanopores for effectively isolating EVs with high purity and yield. Using two different uniform nanoporous track-etched membranes (50 and 200 nm), only the particles in the small EV (sEV) size range were separated through a size-exclusion mechanism. Comparative analysis with the existing ultrafiltration membrane-based TFF system revealed that the nanoporous membrane-based TFF (Nano-TFF) system exhibited a separation efficiency (yield) exceeding twofold, achieving sEVs purity surpassing 90%. The efficacy of the highly purified sEVs was validated by incorporating them into wound dressing material and applying them to a wound animal model. Notably, the sEVs-loaded wound dressing group demonstrated enhanced wound recovery compared to control groups. The Nano-TFF system, which provides precise separation and high efficiency, can be applied to separate various bioactive agents, including sEVs, that require high-purity isolation.

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Mononuclear cells (MNCs), a type of leukocyte, require enrichment owing to their rarity for research and clinical applications. The enrichment of MNCs is generally performed via conventional methods (e.g., density gradient centrifugation). However, these methods have downsides, such as being labor intensive, energy and time consuming, and requiring advanced equipment. Therefore, inertial microfluidics has recently drawn widespread attention as a way to overcome these limitations. This work aims to investigate MNC separation using a novel spiral inertial microfluidic system design. After MNCs were enriched by Ficoll stratification, the cells were separated according to their size and deformability properties by passing through the microfluidic system. In the final step, various cell markers were examined for characterization in these cells collected at outlets. In this paper, we determined that MNCs obtained from three different hematological products could be sorted with a recovery rate of 97.5% and a purity level of 84%, whereas red blood cells (RBCs) had a depletion ratio of 80% using Sunflower-designed microfluidic system. The loss of MNCs in this system was much lower than that in density gradient centrifugation. The separation technique studied here has several advantages, such as continuous processing, a high operation flow rate (e.g., 0.7 ml/min), simplifying the operative procedures for automation, and creating no clogging problems. Additionally, this technique can be easily integrated with downstream applications, such as direct analysis of MNCs via a flow cytometer, and can reduce the number of man-hand manipulation processes.

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Conventional in vitro and preclinical animal models often fail to accurately replicate the complexity of human diseases, limiting the success of translational studies and contributing to the low success rate of clinical trials (Ingber 2016). In response, research has increasingly focused on organ-on-chip technology, which better mimics human tissue interfaces and organ functionality. In this study, we describe the fabrication of a novel biomembrane made of porous silicon (PSi) for use in organ-on-chip systems. This biomembrane more accurately simulates the complex tissue interfaces observed in vivo compared to conventional organ-on-chip interfaces. By leveraging established semiconductor techniques, such as anisotropic chemical etching and electrochemical anodization, we developed a reproducible method to create ultra-thin freestanding PSi biomembranes. These membranes were thinned to approximately 10 μm and anodized to contain nanoporous structures (~ 15 nm diameter) that permeate the entire membrane. The incorporation of these membranes into organ-on-chip-like devices demonstrated their functionality in a lung-on-a-chip (LOAC) model system. The results indicate that the PSi biomembranes support cellular viability and adhesion, and are consistent with the expected diffusion of nutrients and signaling molecules between distinct cell types. This novel approach provides a reliable method for generating PSi biomembranes tailored to mimic tissue interfaces. The study underscores the potential of PSi-based membranes to enhance the accuracy and functionality of organ-on-chip devices in translational research.

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Membrane-bound extracellular vesicles (EVs) are more than mere messengers; they are the carriers of intercellular communication, carrying biomolecules for regulatory processes. They have potential in biomarker discovery and disease diagnosis for clinical applications. However, the exploration and utilization of EVs are currently constrained by the existing processing methodologies. Microfluidic technology is a versatile platform, achieving the efficient, consistent, and precise separation and aggregation of particles from the nanoscale to the microscale. It has great potential for EVs, enabling precise manipulation, separation, and aggregation in microchannels. This review explores active and passive microfluidic techniques, presenting a cost-effective and scalable solution for label-free separation. Their development is important for EV research, unlocking value in the in-depth study. Their innovative biomedical applications can revolutionize laboratory medicine, drug delivery, and regenerative medicine by fully realizing and harnessing the potential of EVs.

Intracellular delivery of therapeutic materials remains challenging, with conventional micropattern-assisted optoporation methods making it difficult to analyze the spatial effects of individual laser pulses. Here, we show that pigmented SU-8 microdisks enable precise analysis of distance-dependent shockwave effects on cell membrane permeabilization, achieving delivery yields up to 60% in optimized conditions. Using 20 μm and 50 μm microdisks irradiated by nanosecond laser pulses, we discovered that larger patterns generate more extensive shockwaves leading to increased cell damage over broader ranges, while smaller patterns maintain high delivery efficiency with minimal cellular disruption. Furthermore, cellular adhesion strength critically influences treatment outcomes: strongly adherent SAOS-2 cells showed remarkable resilience while weakly adherent HEK-293 cells experienced extensive damage at greater distances. Our results demonstrate how micropattern size and cell-specific properties determine the spatial extent and efficiency of shockwave-mediated delivery, providing a framework for optimizing intracellular delivery strategies while preserving cell viability.