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Microsystems & Nanoengineering 2024The introduction of flows within sessile droplets is highly effective for many lab-on-a-chip chemical and biomedical applications. However, generating such flows is...
The introduction of flows within sessile droplets is highly effective for many lab-on-a-chip chemical and biomedical applications. However, generating such flows is difficult due to the typically small droplet volumes. Here, we present a simple, non-contact strategy to generate internal flows in sessile droplets for enhancing mixing and mass transport. The flows are driven by actuating a rigid substrate into oscillation with certain amplitude distributions without relying on the resonance of the droplet itself. Substrate oscillation characteristics and corresponding flow patterns are documented herein. Mixing indices and mass transfer coefficients of sessile droplets on the substrate surface are measured using optical and electrochemical methods. They demonstrate complete mixing within the droplets in 1.35 s and increases in mass transfer rates of more than seven times static values. Proof of concept was conducted with experiments of silver nanoparticle synthesis and with heavy metal ion sensing employing the sessile droplet as a microreactor for synthesis and an electrochemical cell for sensing. The degrees of enhancement of synthesis efficiency and detection sensitivity attributed to the internal flows are experimentally documented.
PubMed: 38919162
DOI: 10.1038/s41378-024-00714-4 -
BMB Reports Jun 2024Hematopoietic stem cell transplantation (HSCT) remains an indispensable therapeutic strategy for various hematological diseases. This review discusses the pivotal role...
Hematopoietic stem cell transplantation (HSCT) remains an indispensable therapeutic strategy for various hematological diseases. This review discusses the pivotal role of bone marrow (BM) niches in influencing the efficacy of HSCT and evaluates the current animal models, emphasizing their limitations and the need for alternative models. Traditional animal models, mainly murine xenograft, have provided significant insights, but due to species-specific differences, are often constrained from accurately mimicking human physiological responses. These limitations highlight the importance of developing alternative models that can more realistically replicate human hematopoiesis. Emerging models that include BM organoids and BM-on-a-chip microfluidic systems promise enhanced understanding of HSCT dynamics. These models aim to provide more accurate simulations of the human BM microenvironment, potentially leading to improved preclinical assessments and therapeutic outcomes. This review highlights the complexities of the BM niche, discusses the limitations of current models, and suggests directions for future research using advanced model systems.
PubMed: 38919014
DOI: No ID Found -
Journal of Nanobiotechnology Jun 2024Parkinson's disease (PD) is the second largest group of neurodegenerative diseases, and its existing drug treatments are not satisfactory. Natural cell membrane drugs...
Parkinson's disease (PD) is the second largest group of neurodegenerative diseases, and its existing drug treatments are not satisfactory. Natural cell membrane drugs are used for homologous targeting to enhance efficacy. In this study, microfluidic electroporation chip prepared mesenchymal stem cell-derived neuron-like cell membrane-coated curcumin PLGA nanoparticles (MM-Cur-NPs) was synthesized and explored therapeutic effect and mechanism in PD. MM-Cur-NPs can protect neuron from damage, restore mitochondrial membrane potential and reduce oxidative stress in vitro. In PD mice, it also can improve movement disorders and restore damaged TH neurons. MM-Cur-NPs was found to be distributed in the brain and metabolized with a delay within 24 h. After 1 h administration, MM-Cur-NPs were distributed in brain with a variety of neurotransmitters were significantly upregulated, such as dopamine. Differentially expressed genes of RNA-seq were enriched in the inflammation regulation, and it was found the up-expression of anti-inflammatory factors and inhibited pro-inflammatory factors in PD. Mechanically, MM-Cur-NPs can not only reduce neuronal apoptosis, inhibit the microglial marker IBA-1 and inflammation, but also upregulate expression of neuronal mitochondrial protein VDAC1 and restore mitochondrial membrane potential. This study proposes a therapeutic strategy provide neuroprotective effects through MM-Cur-NPs therapy for PD.
Topics: Animals; Mesenchymal Stem Cells; Mice; Apoptosis; Nanoparticles; Neurons; Parkinson Disease; Inflammation; Cell Membrane; Membrane Potential, Mitochondrial; Curcumin; Mice, Inbred C57BL; Microfluidics; Male; Oxidative Stress
PubMed: 38918856
DOI: 10.1186/s12951-024-02587-1 -
Microsystems & Nanoengineering 2024Separating plasma from whole blood is an important sample processing technique required for fundamental biomedical research, medical diagnostics, and therapeutic...
Separating plasma from whole blood is an important sample processing technique required for fundamental biomedical research, medical diagnostics, and therapeutic applications. Traditional protocols for plasma isolation require multiple centrifugation steps or multiunit microfluidic processing to sequentially remove large red blood cells (RBCs) and white blood cells (WBCs), followed by the removal of small platelets. Here, we present an acoustofluidic platform capable of efficiently removing RBCs, WBCs, and platelets from whole blood in a single step. By leveraging differences in the acoustic impedances of fluids, our device generates significantly greater forces on suspended particles than conventional microfluidic approaches, enabling the removal of both large blood cells and smaller platelets in a single unit. As a result, undiluted human whole blood can be processed by our device to remove both blood cells and platelets (>90%) at low voltages (25 Vpp). The ability to successfully remove blood cells and platelets from plasma without altering the properties of the proteins and antibodies present creates numerous potential applications for our platform in biomedical research, as well as plasma-based diagnostics and therapeutics. Furthermore, the microfluidic nature of our device offers advantages such as portability, cost efficiency, and the ability to process small-volume samples.
PubMed: 38915828
DOI: 10.1038/s41378-024-00707-3 -
BioRxiv : the Preprint Server For... Jun 2024Arterial thrombosis, which represents a critical complication of cardiovascular diseases, is a leading cause of death and disability worldwide with no effective bioassay...
Arterial thrombosis, which represents a critical complication of cardiovascular diseases, is a leading cause of death and disability worldwide with no effective bioassay for clinical prediction. As a symbolic feature of arterial thrombosis, severe stenosis in the blood vessel creates a high-shear, high-gradient flow environment that effectively facilitates platelet aggregation towards vessel occlusion even with platelet amplification loops inhibited. However, no approach is currently available to comprehensively characterize the size, composition and platelet activation status of thrombi forming under this biorheological condition. Here, we present a thrombus profiling assay that monitors the multi-dimensional attributes of thrombi forming in conditions mimicking the physiological scenario of arterial thrombosis. Using this platform, we demonstrate that different receptor-ligand interactions contribute distinctively to the composition and activation status of the thrombus. Our investigation into hypertensive and older individuals reveals intensified biomechanical thrombogenesis and multi-dimensional thrombus profile abnormalities, demonstrating a direct contribution of mechanobiology to arterial thrombosis and endorsing the diagnostic potential of the assay. Furthermore, we identify the hyperactivity of GPIbα-integrin α β mechanosensing axis as a molecular mechanism that contributes to hypertension-associated arterial thrombosis. By studying the interactions between anti-thrombotic inhibitors and hypertension, and the inter-individual variability in personal thrombus profiles, our work reveals a critical need for personalized anti-thrombotic drug selection that accommodates each patient's pathological profile.
PubMed: 38915705
DOI: 10.1101/2024.06.11.598290 -
BioRxiv : the Preprint Server For... Jun 2024Electroactive organisms contribute to metal cycling, pollutant removal, and other redox-driven environmental processes. Studying this phenomenon in high-throughput is...
Electroactive organisms contribute to metal cycling, pollutant removal, and other redox-driven environmental processes. Studying this phenomenon in high-throughput is challenging since extracellular reduction cannot easily be traced back to its cell of origin within a mixed population. Here, we describe the development of a microdroplet emulsion system to enrich EET-capable organisms. We validated our system using the model electroactive organism and describe the tooling of a benchtop microfluidic system for oxygen-limited processes. We demonstrated enrichment of EET-capable phenotypes from a mixed wild-type and EET-knockout population. As a proof-of-concept application, bacteria were collected from iron sedimentation from Town Lake (Austin, TX) and subjected to microdroplet enrichment. We observed an increase in EET-capable organisms in the sorted population that was distinct when compared to a population enriched in a bulk culture more closely akin to traditional techniques for discovering EET-capable bacteria. Finally, two bacterial species, and not previously shown to be electroactive, were further cultured and characterized for their ability to reduce channel conductance in an organic electrochemical transistor (OECT) and to reduce soluble Fe(III). We characterized two bacterial species not previously shown to exhibit electrogenic behavior. Our results demonstrate the utility of a microdroplet emulsions for identifying putative EET-capable bacteria and how this technology can be leveraged in tandem with existing methods.
PubMed: 38915652
DOI: 10.1101/2024.06.13.598847 -
Microbial Cell Factories Jun 2024With the current progress in the 'design' and 'build' stages of the 'design-build-test-learn' cycle, many synthetic biology projects become 'test-limited'. Advances in... (Review)
Review
With the current progress in the 'design' and 'build' stages of the 'design-build-test-learn' cycle, many synthetic biology projects become 'test-limited'. Advances in the parallelization of microbes cultivations are of great aid, however, for many species down-scaling leaves a metabolic footprint. Yarrowia lipolytica is one such demanding yeast species, for which scaling-down inevitably leads to perturbations in phenotype development. Strictly aerobic metabolism, propensity for filamentation and adhesion to hydrophobic surfaces, spontaneous flocculation, and high acidification of media are just several characteristics that make the transfer of the micro-scale protocols developed for the other microbial species very challenging in this case. It is well recognized that without additional 'personalized' optimization, either MTP-based or single-cell-based protocols are useless for accurate studies of Y. lipolytica phenotypes. This review summarizes the progress in the scaling-down and parallelization of Y. lipolytica cultures, highlighting the challenges that occur most frequently and strategies for their overcoming. The problem of Y. lipolytica cultures down-scaling is illustrated by calculating the costs of micro-cultivations, and determining the unintentionally introduced, thus uncontrolled, variables. The key research into culturing Y. lipolytica in various MTP formats and micro- and pico-bioreactors is discussed. Own recently developed and carefully pre-optimized high-throughput cultivation protocol is presented, alongside the details from the optimization stage. We hope that this work will serve as a practical guide for those working with Y. lipolytica high-throughput screens.
Topics: Yarrowia; High-Throughput Screening Assays
PubMed: 38915032
DOI: 10.1186/s12934-024-02465-3 -
Sheng Wu Gong Cheng Xue Bao = Chinese... Jun 2024Cell culture is a fundamental tool for cell-based assays in biological and preclinical research. The measurements of cell culture, including cell count, viability, and... (Review)
Review
Cell culture is a fundamental tool for cell-based assays in biological and preclinical research. The measurements of cell culture, including cell count, viability, and metabolic activity, can reflect the conditions of cells under culture conditions. The conventional cell culture and detection methods have problems such as high consumption of reagents and samples, inability to monitor cell status in real time, and difficulty in spatiotemporally adjusting the cell microenvironment. A cell impedance sensor measures changes in the electrical impedance of cells through alternating current, enabling real-time monitoring of impedance changes caused by cell activities such as attachment, growth, proliferation, and migration. Microfluidic chips are praised for reducing complex biological processes, integrating multiple analysis modes, and achieving high automation in detection. Integrating microfluidic chips with cell impedance sensors greatly improves the capability and efficiency of cell-related analysis. This review outlines the application of microfluidic chip-based impedance sensors in 2D and 3D cell systems and summarizes the research progress in application of such sensors in research on cell growth, proliferation, viability, metabolic activity, and drug screening. Finally, this review prospects the future development trends and possible challenges, providing ideas for the development of microfluidic chips integrated with electrical impedance sensors in drug screening.
Topics: Electric Impedance; Humans; Biosensing Techniques; Cell Culture Techniques; Microfluidic Analytical Techniques; Cell Proliferation; Cell Survival; Lab-On-A-Chip Devices; Animals
PubMed: 38914492
DOI: 10.13345/j.cjb.230668 -
Microsystems & Nanoengineering 2024Assays mimicking in vitro the concentration gradients triggering biological responses like those involved in fighting infections and blood clotting are essential for...
Assays mimicking in vitro the concentration gradients triggering biological responses like those involved in fighting infections and blood clotting are essential for biomedical research. Microfluidic assays prove especially attractive as they allow precise control of gradient shape allied to a reduction in scale. Conventional microfluidic devices are fabricated using solid plastics that prevent direct access to responding cells. Fluid-walled microfluidics allows the manufacture of circuits on standard Petri dishes in seconds, coupled to simple operating methods; cell-culture medium sitting in a standard dish is confined to circuits by fluid walls made of an immiscible fluorocarbon. We develop and experimentally validate an analytical model of diffusion between two or more aqueous streams flowing at different rates into a fluid-walled conduit with the cross-section of a circular segment. Unlike solid walls, fluid walls morph during flows as pressures fall, with wall shape changing down the conduit. The model is validated experimentally for Fourier numbers < 0.1 using fluorescein diffusing between laminar streams. It enables a priori prediction of concentration gradients throughout a conduit, so allowing rapid circuit design as well as providing bio-scientists with an accurate way of predicting local concentrations of bioactive molecules around responsive and non-responsive cells.
PubMed: 38911344
DOI: 10.1038/s41378-024-00698-1 -
Frontiers in Immunology 2024The immune memory is one of the defensive strategies developed by both unicellular and multicellular organisms for ensuring their integrity and functionality. While the... (Review)
Review
The immune memory is one of the defensive strategies developed by both unicellular and multicellular organisms for ensuring their integrity and functionality. While the immune memory of the vertebrate adaptive immune system (based on somatic recombination) is antigen-specific, encompassing the generation of memory T and B cells that only recognize/react to a specific antigen epitope, the capacity of vertebrate innate cells to remember past events is a mostly non-specific mechanism of adaptation. This "innate memory" can be considered as germline-encoded because its effector tools (such as innate receptors) do not need somatic recombination for being active. Also, in several organisms the memory-related information is integrated in the genome of germline cells and can be transmitted to the progeny for several generations, but it can also be erased depending on the environmental conditions. Overall, depending on the organism, its environment and its living habits, innate immune memory appears to be a mechanism for achieving better protection and survival against repeated exposure to microbes/stressful agents present in the same environment or occurring in the same anatomical district, able to adapt to changes in the environmental cues. The anatomical and functional complexity of the organism and its lifespan drive the generation of different immune memory mechanisms, for optimal adaptation to changes in the living/environmental conditions. The concept of innate immunity being non-specific needs to be revisited, as a wealth of evidence suggests a significant degree of specificity both in the primary immune reaction and in the ensuing memory-like responses. This is clearly evident in invertebrate metazoans, in which distinct scenarios can be observed, with both non-specific (immune enhancement) or specific (immune priming) memory-like responses. In the case of mammals, there is evidence that some degree of specificity can be attained in different situations, for instance as organ-specific protection rather than microorganism-specific reaction. Thus, depending on the challenges and conditions, innate memory can be non-specific or specific, can be integrated in the germline and transmitted to the progeny or be short-lived, thereby representing an exceptionally plastic mechanism of defensive adaptation for ensuring individual and species survival.
Topics: Animals; Immunologic Memory; Immunity, Innate; Humans; Germ Cells; Adaptation, Physiological
PubMed: 38903500
DOI: 10.3389/fimmu.2024.1386578