Fluidic Cell Research Articles

Carcinoembryonic antigen and cancer antigen 125 simultaneously determined using a fluidics-integrated dual carbon electrode

Carcinoembryonic antigen (CEA) and cancer antigen 125 (CA125) are important tumor markers for the diagnosis of ovarian cancer at the metastasis stage. Here, CEA and CA125 were simultaneously detected by a label-free electrochemical immunosensor. Using a stencil and carbon ink, a dual carbon electrode (DCE) was fabricated on a poly(vinyl chloride) substrate. Gold particles (AuPs) were electrodeposited on the electrode as a signal amplifier and support for immobilized antibodies. Linear sweep voltammetry was utilized to detect the tumor markers based on the specific binding of antigens to antibodies. Scanning electron microscopy and atomic force microscopy were used to characterize the fabricated DCE. The results were compared to those of a commercial DCE. Using the developed DCE immunosensor, we achieved a linear range of CEA from 0.5 to 25 ng mL−1 and a linear range of CA125 from 2 to 50 U mL−1. The limits of detection of CEA and CA125 were 0.15 ng mL−1 and 0.6 U mL−1, respectively. The reliability of the immunosensor was evaluated using human serum. The results were consistent with those obtained from the reference enzyme-linked fluorescence assay. The immunosensor was integrated with a small plasma membrane to form a fluidic cell (Flu-iDCE) based on acrylic sheet. The membrane had no effect on the detection of the tumor markers with the proposed Flu-iDCE. This first report of a fluidic device integrated with a DCE demonstrates the potential of the device for point-of-care detection of CEA and CA125.

Numerical heat and mass transfer in magnetized Williamson liquid motion over a sensor wall engulfed in a micro-cantilever system: An application to thin-film fluidic cells

Central focus of this numerical analysis is to investigate the influence of magnetic body force and thermal radiation on the time-dependent electrically conducting two-dimensional viscous incompressible boundary layer flow of non-Newtonian Williamson fluid over a microcantilever sensor surface suspended in a squeezed regime numerically. A novel heat source/sink and Soret effects are included in the respective governing equations. The constructed time-dependent nonlinear coupled partial differential equations are solved by using a bobust RK-4 technique. Increasing magnetic number increases the velocity distribution and decreases the temperature and concentration profiles in the flow regime.Enhancing Soret number increases the mass diffusion profile. Increasing magnetic number suppress the skin-friction coefficient. Heat transport rate booted with rising radiation number and Sherwood number decreased with enlarged Schmidt number in the channel regime. Finally, the numerical accuracy of the present similarity solutions and used numerical method is validated with existing results and observed a remarkable agreement.

Interplay of electrokinetic effects in nonpolar solvents for electronic paper displays

HypothesisElectronic paper displays rely on electrokinetic effects in nonpolar solvents to drive the displacement of colloidal particles within a fluidic cell. While Electrophoresis (EP) is a well-established and frequently employed phenomenon, electro-osmosis (EO), which drives fluid flow along charged solid surfaces, has not been studied as extensively. We hypothesize that by exploiting the interplay between these effects, an enhanced particle transport can be achieved. ExperimentsIn this study, we experimentally investigate the combined effects of EP and EO for colloidal particles in non-polar solvents, driven by an electric field. We use astigmatism micro-particle tracking velocimetry (A-μPTV) to measure the motion of charged particles within model fluidic cells. Using a simple approach that relies on basic fluid flow properties we extract the contributions due to EP and EO, finding that EO contributes significantly to particle transport. The validity of our approach is confirmed by measurements on particles with different magnitudes of charge, and by comparison to numerical simulations. FindingsWe find that EO flows can play a dominant role in the transport of particles in electrokinetic display devices. This can be exploited to speed up particle transport, potentially yielding displays with significantly faster switching times.

Single-cell force spectroscopy of fluid flow-tuned cell adhesion for dissecting hemodynamics in tumor metastasis.

Cell adhesion plays an important role in regulating the metastasis of cancer cells, and atomic force microscopy (AFM)-based single-cell force spectroscopy (SCFS) has become an important method to directly measure the adhesion forces of individual cells. Particularly, bodily fluid flow environments strongly affect the functions and behaviors of metastatic cells for successful dissemination. Nevertheless, the interactions between fluidic flow medium environment and cell adhesion remain poorly understood. In this work, AFM-based SCFS was exploited to examine the effects of fluidic flow environment on cellular adhesion. A fluidic cell culture medium device was used to simulate the fluidic flow environment experienced by cancer cells during metastasis, which was combined with AFM-based SCFS assay. A single living cancer cell was attached to the AFM tipless cantilever to prepare the single-cell probe for performing SCFS experiments on the mesothelial cells grown under the fluidic flow medium conditions, and the effects of experimental parameters (retraction speed, contact time, loading force) on the measured cellular adhesion forces were analyzed. Experimental results of SCFS assay show that cellular adhesion forces significantly decrease after growth in fluidic flow medium, whereas cellular adhesion forces increase after growth in static culture medium. Experiments performed with the use of spherical probes coated with cell adhesion-associated biomolecules also show the weakening of cell adhesion after growth in fluidic flow cell culture medium, which was subsequently confirmed by the confocal fluorescence microscopy experiments of cell adhesion molecules, vividly illustrating the remarkable effects of fluidic flow environment on cellular adhesion. The study provides a new approach to detect adhesion force dynamics involved in the interactions between cells and the fluidic flow environment at the single-cell level, which will facilitate dissecting the role of hemodynamics in tumor metastasis.

261 Characterization of Glycosylation Patterns of Single IgA Molecules Using Single-Molecule Fluorescence Microscopy

OBJECTIVES/GOALS: IgA1 nephropathy, which can lead to kidney failure, is caused by complexes formed between aberrant galactose-deficient IgA1 and antibodies directed against it. Our goals are to characterize shifting glycosylation patterns at the level of single IgA1 molecules and to apply this to patient samples for early detection and understanding of the disease. METHODS/STUDY POPULATION: To characterize glycosylation patterns on single IgA1 molecules, labelled IgA1 in low concentration was physisorbed to borosilicate glass in a fluidic cell and labelled Jacalin was flowed in to bind with Glycans on IgA1. The samples were observed with a Nikon TiE epi-fluorescence microscope. FRET images were created by exciting the Jacalin dye with a blue laser and recording the red emission of the IgA1 dye with an EMCCD camera. FRET emission intensities of individual IgA1 molecules over time were analyzed to determine how frequent and how long Jacalin binds to each of them. The rate of binding is roughly inversely proportional to the amount of abnormal glycans on a given IgA1 molecule. After the method is perfected, we intend to compare the glycosylation patterns of healthy and diseased patient samples. RESULTS/ANTICIPATED RESULTS: Addition of the competitive binder Galactose to the solution led to an increase in the off times of Jacalin and IgA1 and a decrease in the on times in a concentration-dependent manner, yielding an increase in the dissociation constant. Dissociation constants of individual molecules within a single experiment vary by 3 orders of magnitude, which cannot be attributed to stochastic fluctuations but rather reflects differences in the adsorption geometry. Nevertheless, the unaffected dissociation constant can be identified. We expect that when this method is applied to samples from healthy and IgA1 Nephropathy patients, specific IgA1 molecules from patients will have higher dissociation constants for Jacalin compared to those from healthy patients. DISCUSSION/SIGNIFICANCE: The binding rates of Jacalin to single IgA1 vary by 3 orders of magnitude. The observed heterogeneity shows the Jacalin probe can differentiate between different IgA1 populations. An understanding of which IgA1 molecules in patient samples are problematic and what their distribution of Glycans is can lead to discovering biomarkers and treatments.

Differential Sensing with Replicated Plasmonic Gratings Interrogated in the Optical Switch Configuration.

A new plasmonic configuration is proposed for application in a sensor and demonstrated for the detection of variations in the bulk refractive index of solutions. The configuration consists of monitoring two diffracted orders resulting from the interaction of a TM-polarized optical beam incident on a grating coupler, operating based on an effect termed the "optical switch". The two monitored diffracted orders enable differential measurements which cancel the drift and perturbations common to both, leading to an improved detection limit, as demonstrated experimentally. The measured switch pattern associated with the grating coupler is in good agreement with theory. Bulk sensing is demonstrated under intensity interrogation via the sequential injection of solutions comprised of glycerol in water into a fluidic cell. A limit of detection of about 10-6 RIU was achieved. The optical switch configuration is easy to implement and is cost-effective, yielding a highly promising approach for the sensing and the real-time detection of biological species.

Interplay of Fluid Mechanics and Matrix Stiffness in Tuning the Mechanical Behaviors of Single Cells Probed by Atomic Force Microscopy.

It is well known that both fluid mechanics and matrix stiffness present within the cellular microenvironments play an essential role in the physiological and pathological processes of cells. However, so far, knowledge of the interplay of fluid mechanics and matrix stiffness in tuning the mechanical behaviors of single cells is still extremely limited. Particularly, atomic force microscopy (AFM) is now an important and standard tool for characterizing the mechanical properties of single living cells. Nevertheless, studies of utilizing AFM to detect cellular mechanics are commonly performed in static medium conditions, which are unable to access the effects of fluidic media on cellular behaviors. Here, by integrating AFM with a fluidic cell medium device and hydrogel technology, the combined effects of fluid mechanics and matrix stiffness on cell mechanics were investigated. A fluidic medium device with tunable fluid mechanics was established to simulate the shear flow effects, and hydrogels were used to fabricate substrates with different stiffnesses for cell growth. Especially, the cantilever of the AFM probe was modified with a microsphere to indent cells for probing cell mechanics. Based on the established experimental platform, the elastic and viscous properties of single living cells grown on substrates with tunable matrix stiffness under fluidic microenvironments were quantitatively measured, and the remarkable alterations in the mechanical properties of cells were unraveled. The subcellular structure changes of cells in fluidic microenvironments were observed by fluorescence microscopy. Further, AFM morphological imaging was used to image living cells grown in fluidic medium conditions, and significant changes in the surface structure and roughness of cells were observed. The study provides a novel way to investigate the synergistic effects of fluid mechanics and matrix stiffness on the behaviors of single cells, which will benefit unveiling the underlying mechanical cues involved the interactions between microenvironments and cells.

Programmable droplets: Leveraging digitally-responsive flow fields to actively tune liquid morphologies.

Stimulus-responsive materials enable programmable and adaptive behaviors. Typical solid-phase systems can only achieve small deformations for applications where shape transformations are beneficial or required. Liquids, in contrast, can self-assemble and achieve very high strains in a multifluid environment. Here we report liquid droplet formation by tuning flow potential within a confined fluidic cell. We digitally inject small volumes of liquid-pigment into an otherwise-transparent liquid layer, generating macroscopic droplet assembly over large areas constrained between closely-spaced plates. Droplet morphology is actively controlled by modulating outlet conditions to tune flow fields. Pattern stability is maintained through control over injection rate, interfacial viscosity difference, and interfacial surface tension. We demonstrate time-dependent droplet formation and migration to achieve spatially-tunable optical properties. Applied as a multi-cell array, we imagine this liquid mechanism will enable scalable pattern dynamics for active shading and visual display technologies.

Reciprocating free-flow isoelectric focusing with online array ultraviolet detector for process monitoring of protein separation

Free-flow isoelectric focusing (FFIEF) is a useful tool for separating and purifying proteins, DNA, cells, and organelles, etc. However, the online monitoring of each fraction during an FFIEF run has not been achieved yet, resulting in a lack of process monitoring of FFIEF. Herein, an online array ultraviolet (UV) detection system was developed for the easy assay of FFE fractions. The detector was integrated with an apparatus of FFIEF with 32 fractions to show the online monitoring, and bovine serum albumin (BSA) and lysozyme were chosen as the model proteins for manifesting the UV detector performance. The experiments revealed that (i) all the fluidic cells had good linearity from 0.03 to 10 mg/mL BSA and fair limits of detection (LODs) of 0.01 mg/mL; (ii) all the cells had good uniformity of UV absorbance; and (iii) the deviations of intra-day and inter-day of UV detector were respectively 3.8% and 5.8%, indicating the fair stability of the UV detector. The UV detector could be well used for the process monitoring of two model proteins through the whole FFIEF run, and the online absorbance assay of proteins at the end of FFIEF. The UV detector herein had the evident potential for rapid and convenient assay of protein fraction in FFIEF as well as other FFE modes.

Renewable Power Generation by Reverse Electrodialysis Using an Ion Exchange Membrane.

Reverse electrodialysis (RED) is a promising technology to extract sustainable salinity gradient energy. However, the RED technology has not reached its full potential due to membrane efficiency and fouling and the complex interplay between ionic flows and fluidic configurations. We investigate renewable power generation by harnessing salinity gradient energy during reverse electrodialysis using a lab-scaled fluidic cell, consisting of two reservoirs separated by a nanoporous ion exchange membrane, under various flow rates () and salt-concentration difference (). The current-voltage (I-V) characteristics of the single RED unit reveals a linear dependence, similar to an electrochemical cell. The experimental results show that the change of inflow velocity has an insignificant impact on the I-V data for a wide range of flow rates explored (0.01–1 mL/min), corresponding to a low-Peclet number regime. Both the maximum RED power density () and open-circuit voltage () increase with increasing . On the one hand, the RED cell’s internal resistance () empirically reveals a power-law dependence of . On the other hand, the open-circuit voltage shows a logarithmic relationship of . These experimental results are consistent with those by a nonlinear numerical simulation considering a single charged nanochannel, suggesting that parallelization of charged nano-capillaries might be a good upscaling model for a nanoporous membrane for RED applications.

Voltammetric Determination of Trace Heavy Metals by Sequential‐injection Analysis at Plastic Fluidic Chips with Integrated Carbon Fiber‐based Electrodes

AbstractThis work describes a sequential injection analysis (SIA) method for on‐line strippping voltammetric determination of Pb(II), Cd(II) and Zn(II) using an injection‐moulded electrochemical fluidic chip consisting of 3 conductive carbon fiber‐loaded polymer electrodes embedded in a plastic fluidic holder. The sample containing the target metals and a solution containing Bi(III) were aspirated in the holding coil of the SIA manifold. Then, the flow was reversed and the two solutions were directed to the fluidic cell through a mixing coil which induced mixing of the two zones. Upon reaching the cell, simultaneous reduction of the target metals and Bi(III) occurred resulting in the formation of a metal‐Bi alloy on the working electrode. Finally, the accumulated metals were stripped off the bismuth‐film electrode via a positive potential scan and the oxidation current was recorded. The experimental variables (concentration of the bismuth plating solution, deposition potential, sample volume, stripping mode) were investigated and the potential interferences were assessed. The limits of quantification were 2.8 μg L−1 for Pb(II), 3.6 μg L−1 for Cd(II) and 4.2 μg L−1 for Zn(II) and the the within‐chip and between‐chip % relative standard deviations were ≤6.3 % and ≤14 %, respectively. Finally, the sensor was applied to the determination of trace metals in a fish food sample.

3D-printed fluidic electrochemical microcell for sequential injection/stripping analysis of heavy metals

In this paper, a 3D-printed microfluidic device is described which is suitable for sequential injection/anodic stripping voltammetric (SIA-ASV) determination of Pb(II) and Cd(II). The fluidic device is manufactured by 3D-printing in a single-step using a dual extruder 3D printer. The device is composed of a microfluidic cell (printed from a non-conductive polylactic acid (PLA) filament) and of 3 electrodes (printed from a conductive carbon-loaded PLA filament) which are integrated within the fluidic cell. During the preconcentration step, a zone of the sample (containing the target cations) and a zone of Bi(III) solution are mixed on-line and the cations are reduced on the working electrode forming a bismuth alloy. The detection step involves a voltametric scan in static solution, in which the accumulated metals are oxidized while the oxidation current is monitored. After the optimization of the relevant parameters, the limit of detection is 0.38 μg L−1 for Pb(II) and 0.57 μg L−1 for Cd(II), while the within-device repeatability and the between-device reproducibility are lower than 4.5% (n = 8) and 9% (n = 6), respectively, for both cations at the 30 μg L−1 level. The device was successfully applied to the simultaneous determination of Pb(II) and Cd(II) in a honey sample.

Top-Down Heterogeneous Colloidal Engineering Using Capillary Assembly of Liquid Particles.

Capillary assembly of liquid particles (CALP) is a microfabrication strategy for engineering arbitrarily shaped polymer colloids. The method entails depositing emulsion particles into patterned microarrays within a fluidic cell: coalescence, polymerization, and extraction of the deposited material engender faceted colloids. Herein, the versatility of CALP is demonstrated by using both consecutive assembly and heterogeneous coassembly to engineer geometrically diverse Janus and patchy colloids. Liquid particles (LPs) can be patterned laterally across the plane of the template by manipulating the capillary immersion force, liquid particle hardness, and rate of coalescence. Bilayers of different polymeric LPs and patchy microarrays are fabricated, comprising solid colloids made from various materials including poly(styrene), p-styryltrimethoxysilane, and iron oxide. Eleven different structures including concentric Janus squares, triblock ellipsoids, and planar tetramer and pentagonal patchy particles are described. All particles are fluorescently labeled, resist flocculation, withstand extended heating, and endure dispersion in organic solvent. Further crystallization and processing into colloid-based microscale devices is therefore anticipated. Heterogeneous CALP combines top-down microfabrication with bottom-up synthesis to engineer nonequilibrium particle structures that cannot be made with wet chemistry. CALP enables the design and fabrication of colloids with complex internal construction to target hierarchical functional materials. Ultimately, the integration of colloidal building blocks comprising multiple components that are independently addressable is crucial for the development of nano/micromaterials such as filtration devices, sensors, diagnostics, solid-state catalysts, and optical electronics.

Microfluidic Cell Stretching for Highly Effective Gene Delivery into Hard-to-Transfect Primary Cells.

Cell therapy and cellular engineering begin with internalizing synthetic biomolecules and functional nanomaterials into primary cells. Conventionally, electroporation, lipofection, or viral transduction has been used; however, these are limited by their cytotoxicity, low scalability, cost, and/or preparation complexity, especially in primary cells. Thus, a universal intracellular delivery method that outperforms the existing methods must be established. Here, we present a versatile intracellular delivery platform that leverages intrinsic inertial flow developed in a T-junction microchannel with a cavity. The elongational recirculating flows exerted in the channel substantially stretch the cells, creating discontinuities on cell membranes, thereby enabling highly effective internalization of nanomaterials, such as plasmid DNA (7.9 kbp), mRNA, siRNA, quantum dots, and large nanoparticles (300 nm), into different cell types, including hard-to-transfect primary stem and immune cells. We identified that the internalization mechanism of external cargos during the cell elongation-restoration process is achieved by both passive diffusion and convection-based rapid solution exchange across the cell membrane. Using fluidic cell mechanoporation, we demonstrated a transfection yield superior to that of other state-of-the-art microfluidic platforms as well as current benchtop techniques, including lipofectamine and electroporation. In summary, the intracellular delivery platform developed in the present study enables a high delivery efficiency (up to 98%), easy operation (single-step), low material cost (<$1), high scalability (1 × 106 cells/min), minimal cell perturbation (up to 90%), and cell type/cargo insensitive delivery, providing a practical and robust approach anticipated to critically impact cell-based research.

A solid-state nanopore-based single-molecule approach for label-free characterization of plant polysaccharides

Polysaccharides are important biomacromolecules existing in all plants, most of which are integrated into a fibrillar structure called the cell wall. In the absence of an effective methodology for polysaccharide analysis that arises from compositional heterogeneity and structural flexibility, our knowledge of cell wall architecture and function is greatly constrained. Here, we develop a single-molecule approach for identifying plant polysaccharides with acetylated modification levels. We designed a solid-state nanopore sensor supported by a free-standing SiNx membrane in fluidic cells. This device was able to detect cell wall polysaccharide xylans at concentrations as low as 5 ng/μL and discriminate xylans with hyperacetylated and unacetylated modifications. We further demonstrated the capability of this method in distinguishing arabinoxylan and glucuronoxylan in monocot and dicot plants. Combining the data for categorizing polysaccharide mixtures, our study establishes a single-molecule platform for polysaccharide analysis, opening a new avenue for understanding cell wall structures, and expanding polysaccharide applications.

LTCC-Based Fluidic Tuners for Low Microwave Frequency Reconfigurable Circuits

This article presents a frequency reconfigurable RF impedance tuner using eight cascaded fluidic cells to cover the frequency band [0.9, 2.4] GHz. The tuner is made of eight fluidic fillable cavities on top of a coplanar waveguide transmission line in a single low-temperature cofired ceramic (LTCC) substrate. Each cavity is either kept empty or filled with deionized (DI) water to alter the substrate's permittivity and so change the tuner's response. Closed-form expressions are derived and used to dimension the tuner's individual cells, while 3-D field simulations are used to complete the design of a single cell and an entire eight-cell tuner. Both components are fabricated, and good agreement between simulation and measured is observed. The fabricated tuner is used to build a fluidic reconfigurable RF amplifier.

Optofluidic Formaldehyde Sensing: Towards On-Chip Integration.

Formaldehyde (HCHO), a chemical compound used in the fabrication process of a broad range of household products, is present indoors as an airborne pollutant due to its high volatility caused by its low boiling point ( °C). Miniaturization of analytical systems towards palm-held devices has the potential to provide more efficient and more sensitive tools for real-time monitoring of this hazardous air pollutant. This work presents the initial steps and results of the prototyping process towards on-chip integration of HCHO sensing, based on the Hantzsch reaction coupled to the fluorescence optical sensing methodology. This challenge was divided into two individually addressed problems: (1) efficient airborne HCHO trapping into a microfluidic context and (2) 3,5–diacetyl-1,4-dihydrolutidine (DDL) molecular sensing in low interrogation volumes. Part (2) was addressed in this paper by proposing, fabricating, and testing a fluorescence detection system based on an ultra-low light Complementary metal-oxide-semiconductor (CMOS) image sensor. Two three-layer fluidic cell configurations (quartz–SU-8–quartz and silicon–SU-8–quartz) were tested, with both possessing a 3.5 µL interrogation volume. Finally, the CMOS-based fluorescence system proved the capability to detect an initial 10 µg/L formaldehyde concentration fully derivatized into DDL for both the quartz and silicon fluidic cells, but with a higher signal-to-noise ratio (SNR) for the silicon fluidic cell () when compared to the quartz fluidic cell (). The signal intensity enhancement in the silicon fluidic cell was mainly due to the silicon absorption coefficient at the excitation wavelength,, which is approximately five times higher than the absorption coefficient at the fluorescence emission wavelength, .

The mechanical responses of advecting cells in confined flow.

Fluid dynamics have long influenced cells in suspension. Red blood cells and white blood cells are advected through biological microchannels in both the cardiovascular and lymphatic systems and, as a result, are subject to a wide variety of complex fluidic forces as they pass through. In vivo, microfluidic forces influence different biological processes such as the spreading of infection, cancer metastasis, and cell viability, highlighting the importance of fluid dynamics in the blood and lymphatic vessels. This suggests that in vitro devices carrying cell suspensions may influence the viability and functionality of cells. Lab-on-a-chip, flow cytometry, and cell therapies involve cell suspensions flowing through microchannels of approximately 100–800 m. This review begins by examining the current fundamental theories and techniques behind the fluidic forces and inertial focusing acting on cells in suspension, before exploring studies that have investigated how these fluidic forces affect the reactions of suspended cells. In light of these studies’ findings, both in vivo and in vitro fluidic cell microenvironments shall also be discussed before concluding with recommendations for the field.

Efficiency calculation and comparison of fluidic and solid-body power sources using corpuscular radiation

Abstract Research done on a set of simple fluidic (with the fluid used as the ionized medium being air under atmospheric pressure) alphavoltaic cells – small ionizing reactors or “nuclear batteries”, designed in the Faculty of Power and Aerospace Engineering of Warsaw University of Technology, Poland – has shown the possibility of accumulation of usable amount of electric charge. Two simple methods are proposed to describe the fluidic alphavoltaic cells in terms of their efficiency. The results of these methods are presented and compared with the efficiencies of other contemporary types of solid-body (semiconductor junction-based) alpha- and betavoltaic cells. The comparison showed that despite the far-reaching simplicity in design, the designed fluidic cells are still more efficient than some of the solid-body devices that use the alpha type of decay.

Detection of single analyte and environmental samples with silicon nitride nanopores: Antarctic dirt particulates and DNA in artificial seawater.

Nanopore sensing is a powerful tool for the detection of biomolecules. Solid-state nanopores act as single-molecule sensors that can function in harsh conditions. Their resilient nature makes them attractive candidates for taking this technology into the field to measure environmental samples for life detection in space and water quality monitoring. Here, we discuss the fabrication of silicon nitride pores from ∼1.6 to 20 nm in diameter in 20-nm-thick silicon nitride membranes suspended on glass chips and their performance. We detect pure laboratory samples containing a single analyte including DNA, BSA, microRNA, TAT, and poly-D-lys-hydrobromide. We also measured an environmental (mixed-analyte) sample, containing Antarctic dirt provided by NASA Ames. For DNA measurements, in addition to using KCl and NaCl solutions, we used the artificial (synthetic) seawater, which is a mixture of different salts mimicking the composition of natural seawater. These samples were spiked with double-stranded DNA (dsDNA) fragments at different concentrations to establish the limits of nanopore sensitivity in candidate environment conditions. Nanopore chips were cleaned and reused for successive measurements. A stand-alone, 1-MHz-bandwidth Chimera amplifier was used to determine the DNA concentration in artificial seawater that we can detect in a practical time scale of a few minutes. We also designed and developed a new compact nanopore reader, a portable read-out device with miniaturized fluidic cells, which can obtain translocation data at bandwidths up to 100 kHz. Using this new instrument, we record translocations of 400 bp, 1000 bp, and 15000 bp dsDNA fragments and show discrimination by analysis of current amplitude and event duration histograms.