Efficacy of cupping therapy in individuals with fibromyalgia. A systematic review of randomized clinical trials.

BACKGROUND: Fibromyalgia is a chronic and idiopathic condition and is among the most common causes of generalized chronic pain, even affecting psychological and cognitive aspects. AIM: To evaluate the efficacy of cupping therapy on pain, quality of life, sleep disorders, and the impact of the disease in subjects with fibromyalgia. METHODS: We searched the Pubmed, CINAHL, Epistemonikos, Scopus, and Web of Science databases. Randomized controlled trials involving adults with fibromyalgia undergoing cupping were included. Pain intensity, quality of life, sleep disturbances, and the impact of fibromyalgia were assessed. We have reported the results using descriptive statistics and narrative synthesis. RESULTS: Two articles with a total of 155 participants were included. Large effect sizes were found for pain intensity, moderate for quality of life, and low for the impact of fibromyalgia and sleep disorders. However, the certainty of the evidence is low for most outcomes except for sleep disorders. CONCLUSIONS: There is a discrepancy in the efficacy of cupping therapy in improving pain intensity, quality of life, sleep disturbances, and disease impact in people with fibromyalgia. Future high-quality randomized clinical trials are required.

Evaluating the Generalizability of Predictive Classifiers Built from DESI Imaging Lipid Data across Mass Spectrometry Platforms.

In this study, we evaluate the generalizability of predictive classifiers built from DESI lipid data for thyroid fine needle aspiration (FNA) biopsy analysis and classification using two high-performance mass spectrometers (time-of-flight and orbitrap) suited with different DESI imaging sources operated by different users. The molecular profiles obtained from thyroid samples with the different platforms presented similar trends, although specific differences in ion abundances were observed. When using a previously published statistical model built to discriminate thyroid cancer from benign thyroid tissues to predict on a new independent data set obtained, agreement for 24 of the 30 samples across the imaging platforms was achieved. We also tested the classifier on six clinical FNAs and obtained agreement between the predictive results and clinical diagnosis for the different conditions. Altogether, our results provide evidence that statistical classifiers generated from DESI lipid data are applicable across different high-resolution mass spectrometry platforms for thyroid FNA classification.

Redox phospholipidomics analysis reveals specific oxidized phospholipids and regions in the diabetic mouse kidney.

While it is generally accepted that oxidative stress impacts the diabetic kidney and contributes to pathogenesis, there is a substantial lack of knowledge about the molecular entity and anatomic location of a variety of reactive species. Here we provide a novel "oxidative stress map" of the diabetic kidney - the first of its kind, and identify specific, oxidized and other reactive lipids and their location. We used the db/db mouse model and Desorption Electrospray Ionization (DESI) mass spectrometry combined with heatmap image analysis. We analyzed a comprehensive array of phospholipid peroxide species in normal (db/m) and diabetic (db/db) kidneys using DESI imaging. Oxilipidomics heatmaps of the kidneys were generated focusing on phospholipids and their potential peroxidized products. We identified those lipids that undergo peroxidation in diabetic nephropathy. Several phospholipid peroxides and their spatial distribution were identified that were specific to the diabetic kidney, with significant enrichment in oxygenated phosphatidylethanolamines (PE) and lysophosphatidylethanolamine. Beyond qualitative and semi-quantitative information about the targets, the approach also reveals the anatomic location and the extent of lipid peroxide signal propagation across the kidney. Our approach provides novel, in-depth information of the location and molecular entity of reactive lipids in an organ with a very heterogeneous landscape. Many of these reactive lipids have been previously linked to programmed cell death mechanisms. Thus, the findings may be relevant to understand what impact phospholipid peroxidation has on cell and mitochondria membrane integrity and redox lipid signaling in diabetic nephropathy.

Chromatographic performance of microfluidic liquid chromatography devices: Experimental evaluation of straight versus serpentine packed channels.

We prepared a series of planar titanium microfluidic (µLC) columns, each 100 mm long, with 0.15, 0.3 and 0.5 mm i.d.'s. The microfluidic columns were packed with 1.8 µm C18 sorbent and tested under isocratic and gradient conditions. The efficiency and peak capacity of these devices were monitored using a micro LC instrument with minimal extra column dispersion. Columns with serpentine channels were shown to perform worse than those with straight channels. The loss of efficiency and peak capacity was more prominent for wider i.d. columns, presumably due to on-column band broadening imparted by the so-called "race-track" effect. The loss of chromatographic performance was partially mitigated by tapering the turns (reduction in i.d. through the curved region). While good performance was obtained for 0.15 mm i.d. devices even without turn tapering, the performance of 0.3 mm i.d. columns could be brought on par with capillary LC devices by tapering down to 2/3 of the nominal channel width in the turn regions. The loss of performance was not fully compensated for in 0.5 mm devices even when tapering was employed; 30% loss in efficiency and 10% loss in peak capacity was observed. The experimental data for various devices were compared using the expected theoretical relationship between peak capacity Pc and efficiency N; (Pc-1) = N0.5 × const. While straight µLC columns showed the expected behavior, the devices with serpentine channels did not adhere to the plot. The results suggest that the loss of efficiency due to the turns is more pronounced than the corresponding loss of peak capacity.

Improving sensitivity and linear dynamic range of intact protein analysis using a robust and easy to use microfluidic device.

We demonstrate an integrated microfluidic LC device coupled to a QTOF capable of improving sensitivity and linearity for intact protein analysis while also tuning the charge state distributions (CSD) of whole antibodies. The mechanism for sensitivity improvement using microflow ESI is demonstrated by shifting of the CSD to higher charge state, and narrowing of the overall CSD. Both of these aspects serve to improve ion current of the most abundant charge state of antibodies and lead to improvement in sensitivity over high flow ESI by a factor of 15×. Current limits of detection are 0.1 ng (on-column) (n = 100, %RSD = 17.5) using IgG glycosylated antibody, as compared to 5 ng (on-column) (n = 10, %RSD = 15) for high flow LC-ESI-MS. In addition to improvements in sensitivity we also observe improvements in linear dynamic range for microflow ESI that results from a combination of lower limits of detection and narrower CSD. An improvement of linear dynamic range of 1.5 orders of magnitude was observed over conventional high flow LC-MS. In cases where the complexity of the antibody limited both sensitivity and spectral charge state resolution, we employed supercharging and decharging mechanisms to further improve sensitivity and charge state spacing resolution. We demonstrate an 89% increase in sensitivity using glycerol that was added post column, with retention of the glycoform resolution. Since large proteins reside in a relatively low noise region of the mass spectra it is possible to realize effects of supercharging for intact proteins, specifically antibodies of 150 kDa, that are less pronounced for peptide supercharging. We also demonstrate a 51% increase in charge state resolution as imidazole was used to generate lower charge states for high-mass ions. The increase in charge state resolution enables more complex antibodies, or antibody mixtures that coelute in the LC, to be deconvoluted more efficiently. In summary, we demonstrate an analytical technique that yields improved sensitivity and quantitative linear dynamic range for intact protein analysis over conventional LC-MS, and yields ease of use for more complex experimentation such as supercharging and decharging experiments.

Repetitive injection method: a tool for investigation of injection zone formation and its compression in microfluidic liquid chromatography.

Sample introduction in microfluidic liquid chromatography often generates wide zones rather than peaks, especially when a large sample volume (relative to column volume) is injected. Formation of wide injection zones can be further amplified when the sample is dissolved in a strong eluent. In some cases sample breakthrough may occur, especially when the injection is performed into short trapping columns. To investigate the band formation and subsequent zone focusing under gradient elution in situations such as these, we developed the Repetitive Injection Method (RIM), based on the temporally resolved introduction of two discrete peaks to a column, mimicking both the leading and trailing edges of a larger, singly injected sample zone. Using titanium microfluidic 0.32 mm I.D. columns, the results of RIM experiments were practically identical to injection of a correspondingly larger single zone volume. It was also experimentally shown that zone width (spacing between two injected peaks) decreases during gradient elution. We utilized RIM experiments to investigate wide sample zones created by strong sample solvent, and subsequent gradient zone focusing for a series of compounds. This experimental work was compared with computationally simulated chromatograms. The success of sample focusing during injection and gradient elution depends not only on an analyte's absolute retention, but also on how rapidly the analyte's retention changes during the mobile phase gradient.

Microfluidic chip for high efficiency electrophoretic analysis of segmented flow from a microdialysis probe and in vivo chemical monitoring.

An effective method for in vivo chemical monitoring is to couple sampling probes, such as microdialysis, to online analytical methods. A limitation of this approach is that in vivo chemical dynamics may be distorted by flow and diffusion broadening during transfer from sampling probe to analytical system. Converting a homogeneous sample stream to segmented flow can prevent such broadening. We have developed a system for coupling segmented microdialysis flow with chip-based electrophoresis. In this system, the dialysis probe is integrated with a PDMS chip that merges dialysate with fluorogenic reagent and segments the flow into 8-10 nL plugs at 0.3-0.5 Hz separated by perfluorodecalin. The plugs flow to a glass chip where they are extracted to an aqueous stream and analyzed by electrophoresis with fluorescence detection. The novel extraction system connects the segmented flow to an electrophoresis sampling channel by a shallow and hydrophilic extraction bridge that removes the entire aqueous droplet from the oil stream. With this approach, temporal resolution was 35 s and independent of distance between sampling and analysis. Electrophoretic analysis produced separation with 223,000 +/- 21,000 theoretical plates, 4.4% RSD in peak height, and detection limits of 90-180 nM for six amino acids. This performance was made possible by three key elements: (1) reliable transfer of plug flow to a glass chip; (2) efficient extraction of aqueous plugs from segmented flow; (3) electrophoretic injection suitable for high efficiency separation with minimal dilution of sample. The system was used to detect rapid concentration changes evoked by infusing glutamate uptake inhibitor into the striatum of anesthetized rats. These results demonstrate the potential of incorporating segmented flow into separations-based sensing schemes for studying chemical dynamics in vivo with improved temporal resolution.

Electrokinetic trapping using titania nanoporous membranes fabricated using sol-gel chemistry on microfluidic devices.

We have developed a new method for analyte preconcentration on a microfluidic device using a porous membrane fabricated via sol-gel chemistry. These porous membranes were fabricated within the channels of glass microfluidic devices exploiting laminar flow to bring an alcoholic sol-gel precursor (titanium isopropoxide in 2-propanol) into contact with an alcohol-water solution at a channel cross intersection. These two streams reacted at the fluidic interface to form a porous titania membrane. The thickness of the membrane could be altered by changing the [H2O]. Analyte concentration was accomplished by applying a voltage across the titania membrane. The level of analyte enrichment was monitored, and enrichment factors of above 4000 in 400 s were obtained for 2,7-dichlorofluorescein.

Synthesis and characterization of a poly(dimethylsiloxane)-poly(ethylene oxide) block copolymer for fabrication of amphiphilic surfaces on microfluidic devices.

A poly(dimethylsiloxane)-poly(ethylene oxide) (PDMS-PEO) vinyl terminated block copolymer has been synthesized via a simple hydrosilylation reaction between hydride-terminated PDMS and PEO divinyl ether. This prepolymer can be subsequently cross-linked into an elastomer in a second hydrosilylation reaction involving a methylhydrosiloxane-dimethylsiloxane copolymer, forming a material suitable for the purposes of fabricating microfluidic devices. The presence of the PEO block in the prepolymer chain results in a much more hydrophilic material following cross-linking. The surface water contact angle of the PDMS-PEO material is 65 degrees +/- 3 (n = 6), as opposed to approximately 110 degrees for native PDMS. Droplets of water straddled by air within molded channels of the PDMS-PEO are concave in shape with contact angles where the fluid meets the side walls of 32 degrees +/- 4 (n = 8), while droplets in PDMS microchannels are more convex with contact angles of 95 degrees +/- 6 (n = 6). The length of the PDMS-PEO prepolymer chain and the multifunctional hydride cross-linker chains appear to dictate the durability of the elastomeric material. Young's modulus measurements yielded values of 0.94 +/- 0.08, 2.6 +/- 0.8, and 1.91 +/- 0.06 MPa for a [5% vinyl excess prepolymer and 10-fold excess of cross-linker], [10% vinyl excess prepolymer and 5-fold excess of cross-linker], and 10:1 PDMS, respectively, confirming that the elasticity of the cross-linked PDMS-PEO is similar to that of PDMS (Sylgard 184:10:1 mixture of elastomeric base to elastomer curing agent). The PDMS-PEO material still possesses enough PDMS character to allow molded channel architectures to be sealed between two pieces of the block copolymer by conformal contact. As a result of the more hydrophilic nature of the material, the channels of devices fabricated from this polymer are self-filling when using aqueous buffers, making it more user-friendly than PDMS for applications calling for background electrolytes void of organic modifiers. Different compositions of PDMS-PEO devices feature different electroosmotic flow values with the 5% vinyl excess prepolymer EOF values of 2.5 +/- 0.7 x 10(-4) and 5.7 +/- 0.8 x 10(-4) cm(2)/(V s) at pHs 6 and 9, respectively, and 1.2 +/- 0.3 x 10(-4) and 2.5 +/- 0.3 x 10(-4) cm(2)/(V s) for the 10% vinyl excess prepolymer device at pHs 6 and 9, respectively.

Sampling and electrophoretic analysis of segmented flow streams using virtual walls in a microfluidic device.

A method for sampling and electrophoretic analysis of aqueous plugs segmented in a stream of immiscible oil is described. In the method, an aqueous buffer and oil stream flow parallel to each other to form a stable virtual wall in a microfabricated K-shaped fluidic element. As aqueous sample plugs in the oil stream make contact with the virtual wall, coalescence occurs and sample is electrokinetically transferred to the aqueous stream. Using this virtual wall, two methods of injection for channel electrophoresis were developed. In the first, discrete sample zones flow past the inlet of an electrophoresis channel and a portion is injected by electroosmotic flow, termed the "discrete injector". With this approach at least 800 plugs could be injected without interruption from a continuous segmented stream with 5.1% RSD in peak area. This method generated up to 1,050 theoretical plates, although analysis of the injector suggested that improvements may be possible. In a second method, aqueous plugs are sampled in a way that allows them to form a continuous stream that is directed to a microfluidic cross-style injector, termed the "desegmenting injector". This method does not analyze each individual plug but instead allows periodic sampling of a high-frequency stream of plugs. Using this system at least 1000 injections could be performed sequentially with 5.8% RSD in peak area and 53,500 theoretical plates. This method was demonstrated to be useful for monitoring concentration changes from a sampling device with 10 s temporal resolution. Aqueous plugs in segmented flows have been applied to many different chemical manipulations including synthesis, assays, sampling processing and sampling. Nearly all such studies have used optical methods to analyze plug contents. This method offers a new way to analyze such samples and should enable new applications of segmented flow systems.

Improved temporal resolution for in vivo microdialysis by using segmented flow.

Microdialysis sampling probes were interfaced to a segmented flow system to improve temporal resolution for monitoring concentration dynamics. Aqueous dialysate was segmented into nanoliter plugs by pumping sample stream into the base of a tee channel structure microfabricated on a PDMS chip that had an immiscible carrier phase (perfluorodecalin) pumped into the cross arm of the tee. Varying the oil flow rate from 0.22 to 6.3 microL/min and sample flow rate from 42 to 328 nL/min allowed control of plug volume, interval between plugs, and frequency of plug generation between 6 and 28 nL, 0.6 and 10 s, and 0.1 and 1.7 Hz, respectively. Temporal resolution of the system, determined by measuring fluorescence in individual sample plugs following step changes of fluorescein concentration at the sampling probe surface, was as good as 15 s. Temporal resolution was independent of both sampling flow rate and distance that samples were pumped from the sampling probe. This effect is due to the prevention of Taylor dispersion of the sample as it was transported by segmented flow. In contrast, without flow segmentation, temporal resolution was worsened from 25 to 160 s as the detection point was moved from the sampling probe to 40 cm downstream. Glucose was detected by modifying the chip to allow enzyme assay reagents to be mixed with dialysate as sample plugs formed. The resulting assay had a detection limit of 50 microM and a linear range of 0.2-2 mM. This system was used to measure glucose in the brain of anesthetized rats. Basal concentration was 1.5 +/- 0.1 mM (n = 3) and was decreased 60% by infusion of high-K(+) solution through the probe. These results demonstrate the potential of microdialysis with segmented flow to be used for in vivo monitoring experiments with high temporal resolution.

Fully integrated microfluidic separations systems for biochemical analysis.

Over the past decade a tremendous amount of research has been performed using microfluidic analytical devices to detect over 200 different chemical species. Most of this work has involved substantial integration of fluid manipulation components such as separation channels, valves, and filters. This level of integration has enabled complex sample processing on miniscule sample volumes. Such devices have also demonstrated high throughput, sensitivity, and separation performance. Although the miniaturization of fluidics has been highly valuable, these devices typically rely on conventional ancillary equipment such as power supplies, detection systems, and pumps for operation. This auxiliary equipment prevents the full realization of a "lab-on-a-chip" device with complete portability, autonomous operation, and low cost. Integration and/or miniaturization of ancillary components would dramatically increase the capability and impact of microfluidic separations systems. This review describes recent efforts to incorporate auxiliary equipment either as miniaturized plug-in modules or directly fabricated into the microfluidic device.

Micellar electrokinetic chromatography of fluorescently labeled proteins on poly(dimethylsiloxane)-based microchips.

MEKC of standard proteins was investigated on PDMS microfluidic devices. Standard proteins were labeled with AlexaFluor(R) 488 carboxylic acid tetrafluorophenyl ester and filtered through a size-exclusion column to remove any small peptides and unreacted label. High-efficiency MEKC separations of these standard proteins were performed using a buffer consisting of 10 mM sodium tetraborate, 25 mM SDS, and 20% v/v ACN. A separation of BSA using this buffer in a 3.0 cm long channel generated a peak with a plate height of 0.38 microm in <20 s. Additional fast separations of myoglobin, alpha-lactalbumin, lysozyme, and cytochrome c also yielded peaks with plate heights ranging from 0.54 to 0.72 microm. All proteins migrated with respect to their individual pIs. To improve the separations, we used a PDMS serpentine chip with tapered turns and a separation distance of 25 cm. The number of plates generated increased linearly with increasing separation distance on the extended separation channel chips; however, the resolution reached an asymptotic value after about 7 cm. This limited the peak capacity of the separation technique to 10-12.

Surface engineering of poly(dimethylsiloxane) microfluidic devices using transition metal sol-gel chemistry.

We report the coating of poly(dimethylsiloxane) (PDMS) microchannels using transition metal sol-gel chemistry and the subsequent characterization of the coatings. The channels were created using soft polymer lithography, and three metal alkoxide sol-gel precursors were investigated, titanium isopropoxide, zirconium isopropoxide, and vanadium triisobutoxide oxide. The metal alkoxides were diffused into the sidewalls of a PDMS channel and subsequently hydrolyzed using water vapor. This procedure resulted in the formation of durable metal oxide surfaces of titania, zirconia, or vanadia. The resulting surfaces were characterized using contact angle, X-ray photoelectron spectroscopy (XPS), Raman, transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), and electroosmotic mobility (EOM) measurements. All of the metal oxide-modified PDMS surfaces were significantly more hydrophilic than native PDMS. Contact angles for the coatings were 90 degrees for PDMS-ZrO2, 61 degrees for PDMS-TiO2, and 19 degrees for PDMS-vanadia. XPS showed the presence of titania, zirconia, and vanadia on the PDMS surface. XPS spectra also showed no chemical modification of the PDMS after the in situ deposition of the particles either in the Si-O, Si-C, or C-H bonds of the PDMS. The particles deposited in situ were imaged with TEM and were found to be homogeneously distributed throughout the bulk of the PDMS. EOM measurements of the inorganic coatings were stable over a period of at least 95 days. Both cathodic and anodic EOMs could be generated depending upon buffer pH used. The points of net zero charge for PDMS-TiO2, PDMS-ZrO2, and PDMS-vanadia channels were calculated using EOM versus pH measurements and were found to be 4.1 +/- 0.25, 6.1 +/- 0.2, and 7.0 +/- 0.43, respectively. In addition to modifying PDMS channels with inorganic coatings, these inorganic coatings were derivatized with various organic functionalities including oligoethylene oxide (OEO), amino, perfluoro, or mercapto groups using silane chemistry. Contact angle measurements for perfluoro, mercapto, amino, and OEO-coated surfaces yielded contact angles of 120 degrees , 76 degrees , 45 degrees , and 23 degrees , respectively. These contact angles did not change over the period of 95 days. OEO-coated channels reduced the EOM by 50% from native PDMS-TiO2 to 0.9 +/- 0.05 x 10(-4) cm2/V.s (n = 5, 5.5% RSD).

High efficiency micellar electrokinetic chromatography of hydrophobic analytes on poly(dimethylsiloxane) microchips.

This paper describes a simple method for the effective and rapid separation of hydrophobic molecules on polydimethylsiloxane (PDMS) microfluidic devices using Micellar Electrokinetic Chromatography (MEKC). For these separations the addition of sodium dodecyl sulfate (SDS) served two critical roles - it provided a dynamic coating on the channel wall surfaces and formed a pseudo-stationary chromatographic phase. The SDS coating generated an EOF of 7.1 x 10(-4) cm(2) V(-1) s(-1) (1.6% relative standard deviation (RSD), n = 5), and eliminated the absorption of Rhodamine B into the bulk PDMS. High efficiency separations of Rhodamine B, TAMRA (6-carboxytetramethylrhodamine, succinimidyl ester) labeled amino acids (AA), BODIPY FL CASE (N-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-propionyl)cysteic acid, succinimidyl ester) labeled AA's, and AlexaFluor 488 labeled Escherichia coli bacterial homogenates on PDMS chips were performed using this method. Separations of Rhodamine B and TAMRA labeled AA's using 25 mM SDS, 20% acetonitrile, and 10 mM sodium tetraborate generated efficiencies > 100,000 plates (N) or 3.3 x 10(6) N m(-1) in <25 s with run-to-run migration time reproducibilities <1% RSD over 3 h. Microchips with 30 cm long serpentine separation channels were used to separate 17 BODIPY FL CASE labeled AA's yielding efficiencies of up to 837,000 plates or 3.0 x 10(6) N m(-1). Homogenates of E. coli yielded approximately 30 resolved peaks with separation efficiencies of up to 600,000 plates or 2.4 x 10(6) N m(-1) and run-to-run migration time reproducibilities of <1% RSD over 3 h.

Microchip separations in reduced-gravity and hypergravity environments.

Microfabricated fluidics technology, e.g., lab-on-a-chip devices, offers many attractive features for performing chemistry and biochemistry on space-based platforms. We have constructed a portable, battery-operated microfluidic platform that was tested under reduced gravity and hypergravity conditions that would be experienced in space flight and launch. This device consisted of a microchip, microchip holder, two 0-8-kV high-voltage power supplies, a high-voltage switch, a solid-state diode-pumped green laser, an optical train, a channel photomultiplier, and an inertial mass measurement unit all under the control of a laptop computer and powered by 10 D-cell alkaline batteries. The unit was tested on NASA's reduced gravity research aircraft at gravity levels that are relevant to NASA's intended use of bioreporter-based microchips for environmental monitoring of space and planetary environments on manned and unmanned spacecraft. Over the course of two flights, 834 fast electrophoretic separations of four amino acids were performed under a variety of gravitational environments including zero-g, Martian-g, lunar-g, and approximately 1.8-g. All separations were performed in less than 12 s and automatically analyzed. After correction with an internal migration standard, the migration time reproducibilities were all <1% relative standard deviation.

Sol-gel modified poly(dimethylsiloxane) microfluidic devices with high electroosmotic mobilities and hydrophilic channel wall characteristics.

Using a sol-gel method, we have fabricated poly(dimethylsiloxane) (PDMS) microchips with SiO2 particles homogeneously distributed within the PDMS polymer matrix. These particles are approximately 10 nm in diameter. To fabricate such devices, PDMS (Sylgard 184) was cast against SU-8 molds. After curing, the chips were carefully removed from the mold and sealed against flat, cured pieces of PDMS to form enclosed channel manifolds. These chips were then solvated in tetraethyl orthosilicate (TEOS), causing them to expand. Subsequently, the chips were placed in an aqueous solution containing 2.8% ethylamine and heated to form nanometer-sized SiO2 particles within the cross-linked PDMS polymer. The water contact angle for the PDMS-SiO2 chips was approximately 90.2 degrees compared to a water contact angle for Sylgard 184 of approximately 108.5 degrees . More importantly, the SiO2 modified PDMS chips showed no rhodamine B absorption after 4 h, indicating a substantially more hydrophilic and nonabsorptive surface than native PDMS. Initial electroosmotic mobilities (EOM) of (8.3+/-0.2)x10(-4) cm2/(V.s) (RSD=2.6% (RSD is relative standard deviation); n=10) were measured. This value was approximately twice that of native Sylgard 184 PDMS chips (4.21+/-0.09)x10(-4) cm2/(V.s) (RSD=2.2%; n=10) and 55% greater than glass chips (5.3+/-0.4)x10(-4) cm2/(V.s) (RSD=7.7%; n=5). After 60 days of dry storage, the EOM was (7.6+/-0.3)x10(-4) cm2/(V.s) (RSD=3.9%; n=3), a decrease of only 8% below that of the initially measured value. Separations performed on these devices generated 80,000-100,000 theoretical plates in 6-14 s for both tetramethylrhodamine succidimidyl ester and fluorescein-5-isothiocyanate derivatized amino acids. The separation distance was 3.5 cm. Plots of peak variance vs analyte migration times gave diffusion coefficients which indicate that the separation efficiencies are within 15% of the diffusion limit.