High Capture Efficiency Research Articles

Dual-Tuning Azole-Based Ionic Liquids for Reversible CO2 Capture from Ambient Air.

A strategy of tuning azole-based ionic liquids for reversible CO2 capture from ambient air was reported. Through tuning the basicity of anion as well as the type of cation, an ideal azole-based ionic liquid with both high CO2 capacity and excellent stability was synthesized, which exhibited a highest single-component isotherm uptake of 2.17 mmol/g at the atmospheric CO2 concentration of 0.4 mbar at 30 °C, even in the presence of water. The bound CO2 can be released by relatively mild heating of the IL-CO2 at 80 °C, which makes it promising for energy-efficient CO2 desorption and sorbent regeneration, leading to excellent reversibility. To the best of our knowledge, these azole-based ionic liquids are superior to other adsorbent materials for direct air capture due to their dual-tunable properties and high CO2 capture efficiency, offering a new prospect for efficient and reversible direct air capture technologies.

TBA magnetically functionalized materials combined with biomass-derived fluorescent probe for Listeria monocytogenes detection in a sandwich-like strategy

Ultrasensitive and simultaneous quantitative detection of Listeria monocytogenes (L. monocytogenes) that can survive in vacuum packaging and frozen food is critical to public health. Herein, teamed boronate affinity (TBA) magnetically functionalized materials combined with biomass fluorescent probe for L. monocytogenes detection in a sandwich-like strategy was established. Firstly, we prepared new TBA magnetically functionalized materials by reducing the pKa value of phenylboronic acid through the TBA strategy in the form of self-assembled intermolecular B-N coordination bonding. To our knowledge, this is the first study where TBA magnetically functionalized materials were utilized for the identification and capture of bacteria, with a high capture efficiency of over 90.8% in spiked lettuce samples for L. monocytogenes (within 35 min), showing superior capture ability. Then, Anti-L. monocytogenes monoclonal antibody was labeled in biomass-derived fluorescent probe with the help of biotin-streptavidin system to achieve specific and sensitive detection of L. monocytogenes. The sandwich-like strategy shows high sensitivity of designed fluorescence sensing platform for L. monocytogenes with a wide linear range (2.2 × 101–2.2 × 106 CFU/mL), a low limit of detection (2.2 × 101 CFU/mL), and a satisfactory recovery rate (85.19%–106.69%) spiked lettuce sample. Notably, the method was low-cost, general and had strong application prospects in the field of food safety.

Lowering Entropic Barriers in Triplex DNA Switches Facilitating Biomedical Applications at Physiological pH

AbstractTriplex DNA switches are attractive allosteric tools for engineering smart nanodevices, but their poor triplex‐forming capacity at physiological conditions limited the practical applications. To address this challenge, we proposed a low‐entropy barrier design to facilitate triplex formation by introducing a hairpin duplex linker into the triplex motif, and the resulting triplex switch was termed as CTNSds. Compared to the conventional clamp‐like triplex switch, CTNSds increased the triplex‐forming ratio from 30 % to 91 % at pH 7.4 and stabilized the triple‐helix structure in FBS and cell lysate. CTNSds was also less sensitive to free‐energy disturbances, such as lengthening linkers or mismatches in the triple‐helix stem. The CTNSds design was utilized to reversibly isolate CTCs from whole blood, achieving high capture efficiencies (>86 %) at pH 7.4 and release efficiencies (>80 %) at pH 8.0. Our approach broadens the potential applications of DNA switches‐based switchable nanodevices, showing great promise in biosensing and biomedicine.

Lowering Entropic Barriers in Triplex DNA Switches Facilitating Biomedical Applications at Physiological pH.

Triplex DNA switches are attractive allosteric tools for engineering smart nanodevices, but their poor triplex-forming capacity at physiological conditions limited the practical applications. To address this challenge, we proposed a low-entropy barrier design to facilitate triplex formation by introducing a hairpin duplex linker into the triplex motif, and the resulting triplex switch was termed as CTNSds. Compared to the conventional clamp-like triplex switch, CTNSds increased the triplex-forming ratio from 30 % to 91 % at pH 7.4 and stabilized the triple-helix structure in FBS and cell lysate. CTNSds was also less sensitive to free-energy disturbances, such as lengthening linkers or mismatches in the triple-helix stem. The CTNSds design was utilized to reversibly isolate CTCs from whole blood, achieving high capture efficiencies (>86 %) at pH 7.4 and release efficiencies (>80 %) at pH 8.0. Our approach broadens the potential applications of DNA switches-based switchable nanodevices, showing great promise in biosensing and biomedicine.

Abstract 3897: Isolation and molecular characterization of exosomes from glioblastoma patients using a microfluidic device after ultrasound-based opening of the blood-brain barrier

Abstract Glioblastoma (GBM) is a highly aggressive tumor of the brain. Current techniques of detection like magnetic resonance imaging and tissue biopsy are inaccurate or highly invasive, requiring alternatives like liquid biopsy. Exosomes are nanosized vesicles that contain cargo, reflective of their cellular origin and have been used for early diagnosis of cancer. However, in GBM, the blood-brain barrier (BBB) leads to a paucity of pathological information in blood. This study investigates the effect of opening the BBB on circulating exosomes and their potential for early detection of GBM using a microfluidic platform (GlioExoChip). In 20 patients enrolled in a clinical trial NCT03744026, a pulsed ultrasound emitter- Sonocloud-9 was implanted into their brains to open the BBB. We show that GlioExoChip isolates GBM-specific exosomes with a high capture efficiency using phosphatidylserine and Annexin-V chemistry. Further, the amount of circulating EVs increases twofold after opening the BBB. Finally, the correlation between tumor growth rate and the exosome concentrations is evaluated longitudinally. Methods: GlioExoChip is a microfluidic platform with a polydimethylsiloxane top and a glass bottom, functionalized with neutravidin-biotinylated annexin-V. Experiments are performed with GBM cell-line derived exosomes, followed by patient plasma. Isolated exosomes are characterized using Nanoparticle tracking analysis (NTA), scanning electron microscopy, Bicinchoninic acid (BCA) assay and western blot. Statistical analyses are performed using Student’s t-test and Pearson correlation. Results: The microfluidic device GlioExoChip has a high capture efficiency of exosomes derived from GBM cell lines, i.e., 93.03±3.31% and 96.77±0.72% for GBM6 and U87, respectively. NTA and BCA showed that 15 times more exosomes were captured from patient plasma when compared with healthy. Further, western blot proved the presence of a glial protein and Flotillin-1 in exosomes isolated from patients. Exosome concentrations varied with different time points after sonication and had an average twofold increase from the BBB opening. In our longitudinal study with 8 patients, an association between the volumetric enhancement of the tumor and exosome concentrations after sonication shows that the average Pearson correlation among short progression-free survival (PFS) patients was 0.73 (avg. p=0.39), while no correlation was seen among long PFS patients (avg. r value=0.10; avg. p-value=0.54). Conclusions: A microfluidic approach was used to investigate the role of circulating exosomes using phosphatidylserine-annexin V chemistry in GBM. BBB opening via sonication leads to an increase in the average GBM-specific exosome concentrations in plasma. Thus, exosomes are promising biomarkers for early detection in GBM. Citation Format: Abha Kumari, Mark Youngblood, Andrew Gould, Yoon-Tae Kang, Li Chen, Karl Habashy, Chris Amidei, Rachel Ward, Cristal Gomez, Guillaume Bouchoux, Michael Canney, Roger Stupp, Adam M. Sonabend, Sunitha Nagrath. Isolation and molecular characterization of exosomes from glioblastoma patients using a microfluidic device after ultrasound-based opening of the blood-brain barrier [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3897.

The Shape Effect of Acoustic Micropillar Array Chips in Flexible Label-Free Separation of Cancer Cells.

The precise isolation of circulating tumor cells (CTCs) from blood samples is a potent tool for cancer diagnosis and clinical prognosis. However, CTCs are present in extremely low quantities in the bloodstream, posing a significant challenge to their isolation. In this study, we propose a non-contact acoustic micropillar array (AMPA) chip based on acoustic streaming for the flexible, label-free capture of cancer cells. Three shapes of micropillar array chips (circular, rhombus, and square) were fabricated. The acoustic streaming characteristics generated by the vibration of microstructures of different shapes are studied in depth by combining simulation and experiment. The critical parameters (voltage and flow rate) of the device were systematically investigated using microparticle experiments to optimize capture performance. Subsequently, the capture efficiencies of the three micropillar structures were experimentally evaluated using mouse whole blood samples containing cancer cells. The experimental results revealed that the rhombus microstructure was selected as the optimal shape, demonstrating high capture efficiency (93%) and cell activity (96%). Moreover, the reversibility of the acoustic streaming was harnessed for the flexible release and capture of cancer cells, facilitating optical detection and analysis. This work holds promise for applications in monitoring cancer metastasis, bio-detection, and beyond.

Sequestration of CO2 using emulsion phase structure

This study proposes a cost-effective method for creating an emulsion structure to capture 100 % of the CO2 released during chemical reactions. The emulsion, composed of water, kerosene, sodium lauryl sulfate (SLS), sodium hydroxide (NaOH), triethylamine (TEA), and amine-functional ion exchange resin (IER), demonstrates high CO2 capture efficiency. Results indicate that a 10 mL emulsion sample could capture 12.72 g of CO2, representing 95.4 % of the total CO2 produced during the chemical reaction between acetic acid and sodium carbonate. In contrast, an ion exchange resin granule captures only 0.01 g of CO2. Consequently, 10 mL of emulsion sample containing 60 units of IER is necessary to achieve 100 % CO2 capture.

Low-resistance and high-tolerance monolithic spiro-bifluorene-based conjugated microporous polymer for co-capture of PM and CO2 in waste gas

The utilization of solid adsorbents for the co-capture of harmful particulate matter (PM) and carbon dioxide (CO2) in industrial exhaust streams represents a crucial component within the emerging field of waste gas terminal treatment technologies. Extensive research has focused on particulate or powdered adsorbents rather than monolithic materials, whereas monolithic adsorbents exhibit superior advantages in practical industrial applications. Herein, a monolithic spiro-bifluorene-based conjugated micro-porous polymer (DS-CMPs) with hierarchical porous and functionalized hollow nanotube structures was proposed. The favorable characteristics exhibited by DS-CMPs encompass a highly delocalized π-π conjugated skeleton, permanent porosity, unique thermal and chemical stability, precisely defined chemical composition, and excellent water vapor tolerance. These inherent qualities guarantee that DS-CMPs employed for the co-capture of PM and CO2 from exhaust gases exhibit exceptional capture efficiency, low permeation resistance, favorable isosteric heat of adsorption (Qst), and recyclability. The reasons behind the high capture efficiency and low permeation resistance of monolithic DS-CMPs were analyzed through mechanistic exploration and Electrostatic Surface Potential (ESP) calculations. Moreover, the stability inherent in the framework structure and physicochemical properties of DS-CMPs can surmount the notable decline in the capturing capability of porous materials utilized within damp and elevated temperature surroundings. Following exposure to elevated humidity (RH = 86 ± 1 %) and high-temperature (500 ℃) conditions, DS-CMPs exhibited a remarkable capture efficiency exceeding 99.00 % for PM2.5. The self-assembly of monolithic DS-CMPs into a smooth array of nanotube bundles effectively reduces the friction between airflow and material, enhances airflow dispersion, and achieves a minimum permeability resistance of only 8 Pa. At a pressure of 1 bar and temperature of 273 K, the CO2 adsorption capacity of DS-CMPs amounts to 2.72 mmol/g. The high absorption capacity for CO2 is primarily attributed to the presence of a significant microporous/mesoporous ratio and notable surface charge differences. In contrast to powdered adsorbents plagued by sample elution and gas pressure drop issues, the monolithic DS-CMPs showcases good mechanical properties, rendering them readily applicable within industrial bed circulation systems to achieve the co-capture of PM and CO2.

UV communication cooperative formation UAV alliance capture algorithm.

The capture of target unmanned aerial vehicles (UAVs) by a UAV formation is one of the important and typical tasks in multi-UAV battlefield operations. In this paper, an ultraviolet (UV) light communication-assisted formation UAV alliance capture algorithm is proposed, which combines UV light communication technology with a capture algorithm. With the help of wireless UV light to assist UAV formation inter-UAV data confidentiality transmission and non-line-of-sight communication, the algorithm integrates the alliance generation algorithm with the region minimization strategy, solves the optimal alliance structure by using the dynamic programming method, and implements the aerial capture of the target UAVs by using the region minimization strategy, so as to complete the task of efficiently capturing multi-targets by the UAV formation in complex scenarios. Simulation comparisons were conducted between the region minimization strategy and the proposed UV communication-assisted formation UAV alliance capture algorithm. The results show that the proposed algorithm reduces energy consumption by 12.73% on average and decreases the average number of algorithm iterations by 27.49% during the UAV formation capture of multiple targets, which verifies its low energy consumption and high capture efficiency.

Decoder-seq enhances mRNA capture efficiency in spatial RNA sequencing.

Spatial transcriptomics technologies with high resolution often lack high sensitivity in mRNA detection. Here we report a dendrimeric DNA coordinate barcoding design for spatial RNA sequencing (Decoder-seq), which offers both high sensitivity and high resolution. Decoder-seq combines dendrimeric nanosubstrates with microfluidic coordinate barcoding to generate spatial arrays with a DNA density approximately ten times higher than previously reported methods while maintaining flexibility in resolution. We show that the high RNA capture efficiency of Decoder-seq improved the detection of lowly expressed olfactory receptor (Olfr) genes in mouse olfactory bulbs and contributed to the discovery of a unique layer enrichment pattern for two Olfr genes. The near-cellular resolution provided by Decoder-seq has enabled the construction of a spatial single-cell atlas of the mouse hippocampus, revealing dendrite-enriched mRNAs in neurons. When applying Decoder-seq to human renal cell carcinomas, we dissected the heterogeneous tumor microenvironment across different cancer subtypes and identified spatial gradient-expressed genes related to epithelial-mesenchymal transition with the potential to predict tumor prognosis and progression.

The paradigm for exceptional iodine capture by nonporous amorphous electron-deficient cyclophanes

Nuclear power emerges as a beacon of hope in tackling the energy crisis. However, the emission of radioactive iodine originating from nuclear waste and accidents poses a serious danger to nature and human well-being. Therefore, it becomes imperative to urgently develop suitable adsorbents capable of iodine capture and long-term storage. It’s generally recognized that achieving high iodine capture efficiency necessitates the presence of electron-rich pores/cavities that facilitate charge-transfer (CT) interactions, as well as effective sorption sites capable of engaging in lone pair interactions with iodine. In this study, an unprecedented iodine capture paradigm by nonporous amorphous electron-deficient tetracationic cycloalkanes in vapor and aqueous solutions is revealed, overturning preconceived notions of iodine trapping materials. A newly reported tetracationic cyclophane, BPy-Box4+, exhibited an exceptional iodine vapor sorption capacity of 3.99 g g−1, remarkable iodine removal efficiency in aqueous media, and outstanding reusability. The iodine capture mechanism is unambiguously elucidated by theoretical calculations and the single-crystal structures of cyclophanes with a gradual increase in iodine content, underlining the vital role of host-guest (1:1 or 1:2) interactions for the enhanced iodine capture. The current study demonstrates a new paradigm for enhanced iodine capture by nonporous amorphous electron-deficient cyclophanes through host-guest complexation.

The CO2 Capture System with a Swing Temperature Moving Bed

Abstract The reduction in CO2 emissions is now a very popular topic. According to the International Energy Agency, CO2 emitted in 2021 was 6% more than that emitted in 2020. Carbon capture and storage (CCS) is gaining popularity as a possible solution to climate change. Experts estimate that industry and power plants will be responsible for 19% of total CO2 emissions by 2050. This paper presents the design of a semi-industrial-scale system for CO2 capture based on the moving bed temperature swing adsorption technology. According to the results of laboratory tests conducted by the SINTEF industry, this technology demonstrates high capture efficiency (>85%). The CO2 capture medium involved in adsorption is activated carbon passing through individual sections (cooling, heating, adsorption), where CO2 is bonded and then released. The heat and mass transfer processes are realised on the developed stand. The heat exchangers use steam and water as the heating/cooling medium. The paper reviews the existing solutions and describes the developed in-house design of heat exchangers that will ensure heat transfer conditions being a trade-off between economic and efficiency-related issues of the CO2 capture process. The designed test stand will be installed in a Polish power plant and is expected to meet the method energy intensity target, set at ≤ 2.7 MJ/kg CO2, with a capture efficiency exceeding 85%. The aim of the work was to develop and solve technical problems that would lead to the construction of a CO2 capture station with parameters mentioned above. This stand uses an innovative method where CO2 is captured by contacting the fluid (gases) with solid particles. The heat exchange associated with the heating and cooling of the adsorbent had to be solved. For this purpose, heat exchangers were designed with high thermal efficiency and to prevent the formation of mounds.

Microfluidic synthesis and accurate immobilization of low-density QD-encoded magnetic microbeads for multiplex immunoassay.

Magnetic-fluorescent microbeads have been widely used in the multiplex detection of biological molecules. The traditional method relies on flow cytometry to decode and analyze the microbeads. Alternative strategies that employ immobilized microbeads on a plane and involve fluorescence imaging to analyze the microbeads have been proposed. Among these strategies, an integrated chip that controls magnetic field contribution using nickel powder pillars and captured microbeads has attracted great attention. Despite its unique advantages such as low manufacturing costs, reusability and high capture efficiency, existing research had been limited by the inability to precisely capture a single microbead, and the overlapping of microbeads has made multiplex immunoassays based on this strategy impossible. In this work, low-density microbeads were prepared in a microfluidic chip using IBOMA as the main monomer. The low density of the microbeads made the preparation of an aqueous suspension easier. An integration of nickel patterns, magnets and channels was carried out and demonstrated the capacity of capturing single microbeads precisely. Fluorescence coding further empowered this method with the ability of multiplex immunoassay, which was verified using three types of IgG, and a calibration curve for the detection of anti-human IgG was established using a sandwich immunoassay. These results show the promising potential of this strategy for biomedical detection.

In situ metal-ion-incorporated photothermal GO films with an adjustable temperature range for personal thermal management

The in situ metal-ion-incorporated photothermal GO films have high light capture efficiency (98.51%) and exceptional photothermal conversion capability (∼61.3 °C), offering temperature adjustability within the range of 39.1–61.3 °C.

Isolation, Identification, and Evaluation of the Predatory Activity of Chinese Arthrobotrys Species towards Economically Important Plant-Parasitic Nematodes.

The current investigation aimed to isolate and identify predatory fungal strains and evaluate their efficacy in mitigating the effects of plant-parasitic nematodes. We successfully isolated three distinct nematophagous fungal strains from soil samples, identified as Arthrobotrys megalosporus, A. oligospora, and A. sinensis, using conventional and molecular identification methodologies. In vitro trials illustrated the high capture efficiency of these fungi against plant-parasitic nematodes. Over an exposure period of 48 h to Aphelenchoides besseyi, Bursaphelenchus xylophilus, and Ditylenchus destructor, A. megalosporus (GUCC220044) displayed predation rates of 99.7%, 83.0%, and 21.1%, respectively. A. oligospora (GUCC220045) demonstrated predation rates of 97.3%, 97.3%, and 54.6%, and A. sinensis (GUCC220046) showed rates of 85.1%, 68.3%, and 19.0% against the same cohort of nematodes. The experimental outcomes substantiate that all three identified fungal strains demonstrate predatory activity against the tested nematodes, albeit with varying efficiencies.

Clathrating CO2 in a Supramolecular Granatohedron Cage with Noncovalent CO2-NH3 Interactions and High CO2 Capture Efficiency under Ambient Conditions.

Organic amine (R-NH2) reagents as dominant chemical sorbents for CO2 capture in industrial processes suffer from high energy compensation for regeneration. Herein, we, for the first time, report the finding of Co(III) coordinating with NH3 molecules regulating the interaction between NH3 and CO2 to electrostatic interactions instead of a chemical reaction and achieve CO2 capture under near-ambient conditions. NH3 coordinating with Co(III) significantly reduces its alkalinity and reactivity with CO2 owing to its lone-pair electron donation during coordination. Under a simple protocol, CO2 induces the crystallization of CO2@[Co(NH3)6][HSO4][SO4] clathrate into a hydrogen-bonded granatohedron cage from a cobaltic hexammine sulfate aqueous solution under a CO2 pressure of 56 and 142 kPa at 275 and 298 K, respectively, with a CO2 uptake weight content of 11.7%. We reveal that CO2 interacts with cobaltous hexammine via supramolecular interactions rather than chemical bonding. The clathrate spontaneously separates from the solution as single crystals and readily releases CO2 under ambient conditions in water for cyclic utilization without further treatment. In such a rapid supramolecular capture process, molecular recognition ensures exclusive CO2 selectivity, and soluble clathrate enables the spontaneous CO2 release at a low energy penalty, exhibiting excellent practical potential in carbon capture.

In situ detection and viability assessment of target microorganisms

Rapid detection and viability assessment of pathogenic microorganisms, without the need for pre-enrichment steps, is critical in clinical microbiology, food safety, environmental quality assessment, and biosecurity. We demonstrate a powerful analytical concept and the related platform that enable in situ rapid detection, separation, sensitive quantification, and viability assessment of targeted microorganisms (bacteria and fungi) from minimally processed samples. This is based on a novel integration of magneto-affine selection and electrical impedance assay. The entire process, from capture to measurement, is executed using controlled magnetic fields to manipulate magnetic particles (MPs)-microbe affinity-based clusters, in a compact, portable setup equipped with cost-effective, single-use chambers. The system was tested for non-invasive in situ evaluation of model bacteria (Escherichia coli) and fungi (Saccharomyces cerevisiae) within clinically relevant concentration ranges, and it was demonstrated amenable for both commercial and custom MPs, proving its high versatility. The high capture efficiency, the ability to provide analytic results within 30 min directly from unprocessed samples (buffer and synthetic urine), and the high sensitivity in distinguishing live and dead cells in dynamic exposures represent significant advancements over existing assays and recommend the system as a screening tool for pathogen presence and antimicrobial susceptibility in clinical and environmental samples.

Evaluation of CLC as a BECCS technology from tests on woody biomass in an auto-thermal 150-kW pilot unit

In this work, woody biomass is converted by chemical looping combustion (CLC) in the auto-thermally operated 150-kW pilot unit at SINTEF Energy Research in Norway, using ilmenite as an oxygen carrier. The pilot unit consists of two inter-connected circulating fluidized bed reactors, being the air and fuel reactor, respectively. The unit is simplified compared to many other lab and pilot units by not having a carbon stripper. The aim of the present study is to evaluate the main performance parameters when operating a relatively large CLC unit in auto-thermal mode, using a cheap natural mineral, ilmenite, as oxygen carrier. Another aspect with the tests is to verify if the omission of a carbon stripper can provide high enough capture efficiencies for solid fuels as biomass, with a large share of volatiles and a char remnant with high reactivity. As a comparison, tests with petcoke were performed, to assess the effect when using a fuel with a low share of volatiles and slow char conversion. The results imply that CO2 capture efficiencies can be well above 95 % in a larger industrial unit operating on biomass, even without a carbon stripper, but that a carbon stripper is definitely needed for fuels with less volatiles and low char reactivity.

A novel microfluidics PMMA/paper hybrid bioimmunosensor for laser-induced fluorescence detection in the determination of alpha-fetoprotein from serum

Low loss and high capture efficiency of target samples are prerequisites for sensitive detection by fluorescence immunosensors. For quantitative and ultrasensitive detection of alpha-fetoprotein (AFP), we designed a novel microfluidics pump-free PMMA/paper hybrid immunosensor. Here, the 2D planar structure of the detection area of the plastic microfluidic chip is improved to a 3D spatial structure, which increases the number of capture antibodies immobilized and the cross-section area of the “intercept” target protein. PMMA channels efficiently transport target proteins. The paper-based, three-dimensional detection area not only increases the amount of immobilization of the captured antibody but also improves the contact probability between the captured antibody and the target protein. This greatly improves the efficiency of immune binding. A laser-induced fluorescence detector is applied to detect the target protein on the paper-based detecting unit. Under optimal conditions, the immunosensor ensures that the reaction time is 12 min and the residual liquid is only 6.1% of the original volume, achieving ultra-sensitive detection of AFP in the range of 0.01 ng/mL to 100 ng/mL with a limit of quantitation (LOQ) as low as 4.5 pg/mL. The recoveries for AFP ranged from 96.6% to 101.5%, which means the hybrid microfluidics chip is reliable and has great potential for early screening.

High-porosity thin membrane for high-efficiency capture of rare cells

High efficiency capture of rare cells such as circulating tumor cells (CTCs) in the blood of cancer-patient is challenging for size-based separation methods, because of the heterogeneity of the cells, the presence of a huge number of background cells (red and white blood cells), and the overlap in size of the rare cells and some of the background cells. In this work, we developed a systematic study to evaluate the parametric dependence of rare cell capture efficiency by using model cells. High-porosity and thin membranes with supporting honeycomb microframe are fabricated by using a two-level lithography technique. They are then integrated into a microfluidic device for real-time monitoring of flow-induced transmembrane pressure with a solution with or without cells. Our results show both experimentally and theoretically a great importance of the pore number of the membrane and the flow rate. When more than 80% of pores are clogged by large background cells, the rare cell capture efficiency decreases significantly. Otherwise, a lossless capture is theoretically achievable with a high-porosity and large-area membrane under optimal flow conditions.