Lab on a Chip最新文献

{"title":"A dual colorimetric-electrochemical microfluidic paper-based analytical device for point-of-care testing of ischemic strokes†","authors":"Silvia Dortez, Marta Pacheco, Teresa Gasull, Agustín G. Crevillen and Alberto Escarpa","doi":"10.1039/D4LC00398E","DOIUrl":"10.1039/D4LC00398E","url":null,"abstract":"<p >A novel microfluidic paper-based analytical device with dual colorimetric and electrochemical detection (dual μPAD) was developed for the assessment of transferrin saturation (TSAT) in samples from ischemic stroke patients. TSAT was calculated from the ratio between transferrin-bound iron, which was colorimetrically measured, and the total iron-binding capacity, which was electrochemically measured. To this end, a μPAD was smartly designed, which integrated both colorimetric and electrochemical detection reservoirs, communicating <em>via</em> a microchannel acting as a chemical reactor, and with preloading/storing capabilities (reagent-free device). This approach allowed the dual and simultaneous determination of both parameters, providing an improvement in the reliability of the results due to an independent signal principle and processing. The μPADs were validated by analyzing a certified reference material, showing excellent accuracy (<em>E</em><small>_r</small> ≤ 5%) and precision (RSD ≤ 2%). Then they were applied to the analysis of diagnosed serum samples from ischemic stroke patients. The results were compared to those provided by a free-interference method (urea-PAGE). Impressively, both methods exhibited a good correlation (<em>r</em> = 0.96, <em>p</em> &lt; 0.05) and no significant differences were found between them (slope 1.0 ± 0.1 and the intercept 1 ± 4, <em>p</em> &lt; 0.05), demonstrating the excellent accuracy of our approach during the analysis of complex samples from ischemic stroke patients, using just 90 μL of clinical samples and taking less than 90 min in comparison with the 18 hours required by the urea-PAGE approach. The developed fully integrated colorimetric-electrochemical μPAD is a promising ready to use reagent-free device for the <em>point-of-care</em> testing of TSAT, which can be used to assist physicians in the fast diagnosis and prognosis of ischemic strokes, where the decision-time is crucial for the patient's survival.</p>","PeriodicalId":85,"journal":{"name":"Lab on a Chip","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2024/lc/d4lc00398e?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141794953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dispersion-free inertial focusing (DIF) for high-yield polydisperse micro-particle filtration and analysis†","authors":"Kelvin C. M. Lee, Bob M. F. Chung, Dickson M. D. Siu, Sam C. K. Ho, Daniel K. H. Ng and Kevin K. Tsia","doi":"10.1039/D4LC00275J","DOIUrl":"10.1039/D4LC00275J","url":null,"abstract":"<p >Inertial focusing excels at the precise spatial ordering and separation of microparticles by size within fluid flows. However, this advantage, resulting from its inherent size-dependent dispersion, could turn into a drawback that challenges applications requiring consistent and uniform positioning of polydisperse particles, such as microfiltration and flow cytometry. To overcome this fundamental challenge, we introduce Dispersion-Free Inertial Focusing (DIF). This new method minimizes particle size-dependent dispersion while maintaining the high throughput and precision of standard inertial focusing, even in a highly polydisperse scenario. We demonstrate a rule-of-thumb principle to reinvent an inertial focusing system and achieve an efficient focusing of particles ranging from 6 to 30 μm in diameter onto a single plane with less than 3 μm variance and over 95% focusing efficiency at highly scalable throughput (2.4–30 mL h<small>⁻¹</small>) – a stark contrast to existing technologies that struggle with polydispersity. We demonstrated that DIF could be applied in a broad range of applications, particularly enabling high-yield continuous microparticle filtration and large-scale high-resolution single-cell morphological analysis of heterogeneous cell populations. This new technique is also readily compatible with the existing inertial microfluidic design and thus could unleash more diverse systems and applications.</p>","PeriodicalId":85,"journal":{"name":"Lab on a Chip","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141794954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Label-free optical detection of calcium ion influx in cell-derived nanovesicles using a conical Au/PDMS biosensor†","authors":"Jisung Kwak, Woochul Kim, Hyerim Cho, Jiyun Han, Sang Jun Sim, Hyun Gyu Song, Yusin Pak and Hyun Seok Song","doi":"10.1039/D4LC00421C","DOIUrl":"10.1039/D4LC00421C","url":null,"abstract":"<p >Ion channels, which are key to physiological regulation and drug discovery, control ion flux across membranes, and their dysregulation leads to various diseases. Ca<small>²⁺</small> monitoring is crucial for cellular signaling when performing Ca-based assays in ion channel research; these assays are widely utilized in both academic and pharmaceutical contexts for drug screening and pharmacological profiling. However, existing detection methods are limited by slow detection speeds, low throughput, complex processes, and low analyte viability. In this study, we developed a label-free optical biosensing method using a conical Au/polydimethylsiloxane platform tailored to detect Ca<small>²⁺</small> influx in A549-originated nanovesicles facilitated by the transient receptor potential ankyrin 1 (TRPA1) channel. Nanovesicles expressing cellular signaling components mimic TRPA1 signal transduction in cell membranes and improve analyte viability. The conical Au/polydimethylsiloxane sensor converted Ca<small>²⁺</small> influx events induced by specific agonist exposure into noticeable changes in relative transmittance under visible light. The optical transmittance change accompanying Ca<small>²⁺</small> influx resulted in an enhanced sensing response, high accuracy and reliability, and rapid detection (∼5 s) without immobilization or ligand treatments. In the underlying sensing mechanism, morphological variations in nanovesicles, which depend on Ca<small>²⁺</small> influx, induce a considerable light scattering change at an interface between the nanovesicle and Au, revealed by optical simulation. This study provides a foundation for developing biosensors based on light–matter interactions. These sensors are simple and cost-effective with superior performance and diverse functionality.</p>","PeriodicalId":85,"journal":{"name":"Lab on a Chip","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2024/lc/d4lc00421c?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141786542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Size-related variability of oxygen consumption rates in individual human hepatic cells†","authors":"Ermes Botte, Yuan Cui, Chiara Magliaro, Maria Tenje, Klaus Koren, Andrea Rinaldo, Roman Stocker, Lars Behrendt and Arti Ahluwalia","doi":"10.1039/D4LC00204K","DOIUrl":"10.1039/D4LC00204K","url":null,"abstract":"<p >Accurate descriptions of the variability in single-cell oxygen consumption and its size-dependency are key to establishing more robust tissue models. By combining microfabricated devices with multiparameter identification algorithms, we demonstrate that single human hepatocytes exhibit an oxygen level-dependent consumption rate and that their maximal oxygen consumption rate is significantly lower than that of typical hepatic cell cultures. Moreover, we found that clusters of two or more cells competing for a limited oxygen supply reduced their maximal consumption rate, highlighting their ability to adapt to local resource availability and the presence of nearby cells. We used our approach to characterize the covariance of size and oxygen consumption rate within a cell population, showing that size matters, since oxygen metabolism covaries lognormally with cell size. Our study paves the way for linking the metabolic activity of single human hepatocytes to their tissue- or organ-level metabolism and describing its size-related variability through scaling laws.</p>","PeriodicalId":85,"journal":{"name":"Lab on a Chip","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2024/lc/d4lc00204k?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141764418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Continuous flow delivery system for the perfusion of scaffold-based 3D cultures†","authors":"Zachary R. Sitte, Elizabeth E. Karlsson, Haolin Li, Haibo Zhou and Matthew R. Lockett","doi":"10.1039/D4LC00480A","DOIUrl":"10.1039/D4LC00480A","url":null,"abstract":"<p >The paper-based culture platform developed by Whitesides readily incorporates tissue-like structures into laboratories with established workflows that rely on monolayer cultures. Cell-laden hydrogels are deposited in these porous scaffolds with micropipettes; these scaffolds support the thin gel slabs, allowing them to be evaluated individually or stacked into thick constructs. The paper-based culture platform has inspired many basic and translational studies, each exploring how readily accessible materials can generate complex structures that mimic aspects of tissues <em>in vivo</em>. Many of these examples have relied on static culture conditions, which result in diffusion-limited environments and cells experiencing pericellular hypoxia. Perfusion-based systems can alleviate pericellular hypoxia and other cell stresses by continually exposing the cells to fresh medium. These perfusion systems are common in microfluidic and organ-on-chip devices supporting cells as monolayer cultures or as 3D constructs. Here, we introduce a continuous flow delivery system, which uses parts readily produced with 3D printing to provide a self-contained culture platform in which cells in paper or other scaffolds are exposed to fresh (flowing) medium. We demonstrate the utility of this device with examples of cells maintained in single cell-laden scaffolds, stacks of cell-laden scaffolds, and scaffolds that contain monolayers of endothelial cells. These demonstrations highlight some possible experimental questions that can be enabled with readily accessible culture materials and a perfusion-based device that can be readily fabricated.</p>","PeriodicalId":85,"journal":{"name":"Lab on a Chip","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141764417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integration of 3D printed Mg2+ potentiometric sensors into microfluidic devices for bioanalysis†","authors":"Sarah Farahani, Dalton L. Glasco, Manar M. Elhassan, Pedaballi Sireesha and Jeffrey G. Bell","doi":"10.1039/D4LC00407H","DOIUrl":"10.1039/D4LC00407H","url":null,"abstract":"<p >Electrochemical sensors provide an affordable and reliable approach towards the detection and monitoring of important biological species ranging from simple ions to complex biomolecules. The ability to miniaturize electrochemical sensors, coupled with their affordability and simple equipment requirements for signal readout, permits the use of these sensors at the point-of-care where analysis using non-invasively obtainable biofluids is receiving growing interest by the research community. This paper describes the design, fabrication, and integration of a 3D printed Mg<small>²⁺</small> potentiometric sensor into a 3D printed microfluidic device for the quantification of Mg<small>²⁺</small> in low-sample volume biological fluids. The sensor employs a functionalized 3D printable photocurable methacrylate-based ion-selective membrane affixed to a carbon-mesh/epoxy solid-contact transducer for the selective determination of Mg<small>²⁺</small> in sweat, saliva and urine. The 3D printed Mg<small>²⁺</small> ion-selective electrode (3Dp-Mg<small>²⁺</small>-ISE) provided a Nernstian response of 27.5 mV per decade with a linear range of 10 mM to 39 μM, covering the normal physiological and clinically relevant levels of Mg<small>²⁺</small> in biofluids. 3Dp-Mg<small>²⁺</small>-ISEs selectively measure Mg<small>²⁺</small> over other biologically present cations – sodium, potassium, calcium, ammonium – as well as provide high stability in the analytical signal with a drift of just 13 μV h<small>⁻¹</small> over 10 hours. Comparison with poly(vinylchloride)-based Mg<small>²⁺</small>-ISEs showed distinct advantages to the use of 3Dp-Mg<small>²⁺</small>-ISEs, with respect to stability, resilience towards biofouling and importantly providing a streamlined and rapid approach towards mass production of selective and reliable sensors. The miniaturization capabilities of 3D printing coupled with the benefits of microfluidic analysis (<em>i.e.</em>, low sample volumes, minimal reagent consumption, automation of multiple assays, <em>etc.</em>), provides exciting opportunities for the realization of the next-generation of point-of-care diagnostic devices.</p>","PeriodicalId":85,"journal":{"name":"Lab on a Chip","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141764424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nanofluidic resistive pulse sensing for characterization of extracellular vesicles†","authors":"Madalena R. C. Calado, Teresa C. Lage, Daniel A. M. André, Carlos Calaza, Carlos Marques, Carolina Herrero, João Piteira, Lars Montelius, Dmitri Y. Petrovykh, Lorena Diéguez and Alar Ainla","doi":"10.1039/D4LC00364K","DOIUrl":"10.1039/D4LC00364K","url":null,"abstract":"<p >This paper describes the development, design and characterization of a resistive pulse sensing (RPS) system for the analysis of size distributions of extracellular vesicles (EVs). The system is based on microfluidic chips fabricated using soft-lithography and operated in pressure-driven mode. This fabrication approach provided reproducible pore dimensions and the best performing chip design enabled, without calibration, sizing of both 252 nm and 460 nm test particles within 8% of theoretically calculated values, based on the size specifications provided by suppliers. The number concentration measurement had higher variations and without calibration provided estimates within an order of magnitude, for sample concentrations across 4 orders of magnitude. The RPS chips could also measure successfully EVs and other biological nanoparticles in purified samples from cell culture media and human serum. A compact, fast and inexpensive RPS system based on this design could be an attractive alternative to current gold-standard techniques for routine characterization of EV samples.</p>","PeriodicalId":85,"journal":{"name":"Lab on a Chip","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2024/lc/d4lc00364k?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141755111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A multiplexed, allele-specific recombinase polymerase amplification assay with lateral flow readout for sickle cell disease detection†","authors":"Megan M. Chang, Mary E. Natoli, Alexis F. Wilkinson, Venée N. Tubman, Gladstone E. Airewele and Rebecca R. Richards-Kortum","doi":"10.1039/D4LC00281D","DOIUrl":"10.1039/D4LC00281D","url":null,"abstract":"<p >Isothermal nucleic acid amplification tests have the potential to improve disease diagnosis at the point of care, but it remains challenging to develop multiplexed tests that can detect ≥3 targets or to detect point mutations that may cause disease. These capabilities are critical to enabling informed clinical decision-making for many applications, such as sickle cell disease (SCD). To address this, we describe the development of a multiplexed allele-specific recombinase polymerase amplification (RPA) assay with lateral flow readout. We first characterize the specificity of RPA using primer design strategies employed in PCR to achieve point mutation detection, and demonstrate the utility of these strategies in achieving selective isothermal amplification and detection of genomic DNA encoding for the healthy β<small>^A</small> globin allele, or genomic DNA containing point mutations encoding for pathologic β<small>^S</small> and β<small>^C</small> globin alleles, which are responsible for most sickle cell disorders. We then optimize reaction conditions to achieve multiplexed amplification and identification of the three alleles in a single reaction. Finally, we perform a small pilot study with 20 extracted genomic DNA samples from SCD patients and healthy volunteers – of the 13 samples with valid results, the assay demonstrated 100% sensitivity and 100% specificity for detecting pathologic alleles, and an overall accuracy of 92.3% for genotype prediction. This multiplexed assay is rapid, minimally instrumented, and when combined with point-of-care sample preparation, could enable DNA-based diagnosis of SCD in low-resource settings. The strategies reported here could be applied to other challenges, such as detection of mutations that confer drug resistance.</p>","PeriodicalId":85,"journal":{"name":"Lab on a Chip","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2024/lc/d4lc00281d?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141755114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A novel microfluidic tool for the evaluation of local drug delivery systems in simulated in vivo conditions","authors":"William A. Oates and Antonios D. Anastasiou","doi":"10.1039/D4LC00181H","DOIUrl":"10.1039/D4LC00181H","url":null,"abstract":"<p >A 3D-printed microfluidic tool for assessing local drug delivery systems (LDD) in simulated <em>in vivo</em> conditions was developed and evaluated. The device was designed considering the oral environment and dental applications, and it was fabricated with a high-precision resin 3D printer. Chitosan scaffolds loaded with different concentrations of doxycycline were used for evaluating our device. The concentration of the released drug was measured through in-line UV-VIS spectroscopy, and to verify the repeatability and accuracy of our measurements, comparisons with standard HPLC results were made (5% deviation). Cumulative drug release profiles in steady-state conditions were obtained and compared to the Weibull model. The behaviour of the LDD system in a dynamic environment was also evaluated during experiments where step changes in pH were introduced. It was demonstrated that under infection-like conditions, there is an immediate response from the polymer and a clear increase in the concentration of the released drug. Continuous flow and recirculation experiments were also conducted, revealing significant differences in the drug release profiles. Specifically, in the case of continuous flow, the quantity of the released drug is much higher due to the higher driving force for diffusion (concentration gradient). Overall, the proposed microfluidic tool proved to be ideal for evaluating LDD systems, as the <em>in vivo</em> microenvironment can be replicated in a better way than with currently used standard systems.</p>","PeriodicalId":85,"journal":{"name":"Lab on a Chip","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2024/lc/d4lc00181h?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141750536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficient discovery of antibody binding pairs using a photobleaching strategy for bead encoding†","authors":"Shira Roth, Tom Ferrante and David R. Walt","doi":"10.1039/D4LC00382A","DOIUrl":"10.1039/D4LC00382A","url":null,"abstract":"<p >Dye-encoded bead-based assays are widely used for diagnostics. Multiple bead populations are required for multiplexing and can be produced using different dye colors, labeling levels, or combinations of dye ratios. Ready-to-use multiplex bead populations restrict users to specific targets, are costly, or require specialized instrumentation. In-house methods produce few bead plexes or require many fine-tuning steps. To expand bead encoding strategies, we present a simple, safe, and cost-effective bench-top system for generating bead populations using photobleaching. By photobleaching commercially available dye-encoded magnetic beads for different durations, we produce three times as many differentiable bead populations on flow cytometry from a single dye color. Our photobleaching system uses a high-power LED module connected to a light concentrator and a heat sink. The beads are photobleached in solution homogeneously by constant mixing. We demonstrate this photobleaching method can be utilized for cross-testing antibodies, which is the first step in developing immunoassays. The assay uses multiple photobleached encoded beads conjugated with capture antibodies to test many binding pairs simultaneously. To further expand the number of antibodies that can be tested at once, several antibodies were conjugated to the same bead, forming a pooled assay. Our assay predicts the performance of antibody pairs used in ultrasensitive Simoa assays, narrowing the number of cross-tested pairs that need to be tested by at least two-thirds and, therefore, providing a rapid alternative for an initial antibody pair screening. The photobleaching system can be utilized for other applications, such as multiplexing, and for photobleaching other particles in solution.</p>","PeriodicalId":85,"journal":{"name":"Lab on a Chip","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141754735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}