Disposable System Research Articles

Grating-coupled surface-plasmon fluorescence DNA sensor

Genetic analysis is considered to be the ultimate diagnostic approach in many fields, e.g., in medicine for disease detection, in agricultural technology for food and feed authentication, in forensics, to name a few. Consequently, great interest is growing in developing sensitive and reliable analytical tools (biosensors) to identify whole DNA sequences, oligonucleotide fragments, or single-nucleotide polymorphisms (SNPs). In addition, these biosensors are becoming vital tools for clinical diagnosis and point-of-care systems. They need to be of high sensitivity, high specificity, fast response, inexpensive, and easy to use. In this work, we discuss a surface-plasmon fluorescence grating coupler-based biosensor, fabricated on polymer substrates, and with a designed surface binding procedure that offers the direct response required for a sensor to be implemented in a disposable system. These gratings fabricated on polymer substrates using an embossing technique showed excellent and reproducible resonance coupling results. We also present a monitoring protocol for hybridization reactions based on fluorescence resonance energy transfer (FRET) to quench the bulk solution contribution that decreases the sensitivity of the grating biosensors.

Development of a disposable cartridge real-time PCR test for detection of Chlamydia trachomatis directly from urine

Abstract We present a PCR assay screening Chlamydia trachomatis directly from urine without pre-amplification or sample clean-up and demonstrate suitability for implementation on a disposable cartridge system. Primers and probes were designed to detect all Chlamydia trachomatis serovars with a high degree of sensitivity and specificity. The assay also incorporated a synthetic internal amplification control to monitor inhibition of the PCR reaction. The assay protocol worked directly on urine samples with initial heating to 85 °C for ten minutes, followed by a duplex realtime PCR (95 °C, 55 °C, 45 cycles) on resulting urine lysate. The test cartridge incorporated heating and liquid manipulation using pinch valves and a compressible blister pouch. Lyophilised PCR reagents were incorporated into the cartridge and were re-suspended by a 40 μL aliquot of the urine lysate. Primers were designed to screen for all Chlamydia trachomatis serovars with a high degree of sensitivity and specificity. Evaluation of the newly developed PCR assay was carried out on the LightCycler™ using urine samples previously confirmed positive or negative for the target pathogen, using the ABBOTT real-time PCR Cobas CT/NG test at a local hospital.

Associations between Physical Function, Bone Density, Muscle Mass and Muscle Morphology in Older Men with Sarcopenia: A Pilot Study.

Background and Objectives: It is thought that muscle and bone interact only on a biomechanical level, however, some research is now emerging that links bone and muscle on a cellular level. The aim of this study was to explore associations between physical function, muscle mass and bone density in community-dwelling elderly men with sarcopenia. A secondary goal was to analyze if muscle morphology was associated with bone density and physical functioning. Materials and Methods: Body composition was measured by dual-energy X-ray absorptiometry (DXA). Bone density was evaluated according to WHO criteria. Sarcopenia was diagnosed according to European Working Group on Sarcopenia in Older People (EWGSOP) criteria: low muscle mass and low muscle strength or low physical performance. Microbiopsy of musculus vastus lateralis was performed with a disposable muscle microbiopsy system. The perimeter and cross-sectional area of muscle fibers were calculated using image analysis software in whole slide images; type of fibers and their distribution were evaluated as well. Results: A total of 151 men, 60 years or older were included in this study. Mean age of the subjects was 72.9 ± 8.02 years. Sarcopenia was diagnosed in 45 (29.8%) men. Multiple significant correlations were found between bone mineral density, lean mass, appendicular lean mass, arm and leg lean mass, gait speed, balance test and handgrip strength in sarcopenic men. Lean mass was associated with femoral neck BMD (bone mineral density; r = 0.418, p = 0.006) and handgrip strength (r = 0.553, p < 0.001). In the sarcopenia group, 25 muscle biopsies were examined. In 9 sarcopenic men with T-scores equal or below −2.5, the muscle fiber area had a significant correlation with the balance test (r = 0.73, p = 0.025). Conclusions: In men with sarcopenia, low lean muscle mass was associated with low femoral neck BMD and low muscle strength. In sarcopenic men with osteoporosis, low muscle fiber area was associated with low scores in a balance test.

A hand-powered microfluidic system for portable and low-waste sample discretization.

In this work, we present a simple and equipment-free system for discretizing samples into tens of thousands of discrete volumes in tens of seconds. Unlike conventional sample discretization systems that require bulky syringe pumps, pressure controllers, or vacuum equipment, our system requires only a sheet of water-soluble film, a hand-operated syringe, and a microfluidic device containing a high-density microchamber array. In this system, the water-soluble film seals the device inlet to form a closed channel-chamber system, while the syringe is used to create a vacuum in the closed system. Benefitting from the high negative pressure created by syringe-vacuum and the dissolution-triggered gating mechanism of the sealing water-soluble film, the aqueous sample loaded into the device inlet can be rapidly partitioned into tens of thousands of isolated chambers without the need for any expensive pumping systems. We demonstrated the utility of this system by exploiting it for digital PCR. We believe that this simple discretization system will find broad applications, such as in digital bioassays, single-cell analysis, and point-of-care diagnostics.

Novel device for preventing diffusion of aerosol droplets from subjects undergoing esophagogastroduodenoscopy during COVID‐19 pandemic

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One-pot synthesized gold nanoparticle-peptide nanotube modified disposable sensor for impedimetric recognition of miRNA 410

In the presented study, gold nanoparticle assembled peptide nanotube (AuNP-PNT) modified graphite sensor system was offered for the first time for the impedimetric analysis of a potential prostate cancer biomarker, circulating miRNA 410, which is secreted by prostate cancer cells and is released into peripheral blood system. The proposed disposable sensor platform was easily constructed through one-pot synthesized nanocomposite modification with physical adsorption. AuNP-PNT nanocomposite and sensor surface features were identified with physicochemical, microscopic and electrochemical methods. The parameters which affect the sensor performance such as nanocomposite adsorption, probe DNA immobilization and hybridization process time-temperature were investigated and optimized. High sensitivity and low detection limit were established as 3.90 fM with a wide linear range from 10 fM to 300 pM for the impedimetric recognition of miRNA 410 based on the hybridization process. Selectivity experiment results proved that the developed surface captured the target miRNA with good base discrimination ability. Furthermore, the fabricated disposable sensor system was successfully applied in peripheral serum with good recovery. The proposed sensor system with its outstanding features such as cheapness, easiness, time effectiveness and sensitivity can be applied as a new sensor surface for the electrochemical detection of important analytes.

Development of a Paper-Based Microfluidic System for a Continuous High-Flow-Rate Fluid Manipulation.

The current study describes the development of a disposable paper-based microfluidic system, which unlike its predecessors that are only capable of processing a small amount of fluid, can continuously process the fluid at a high flow rate of up to 1.5 mL/min. The fabrication procedure was clean-room-free and robust, involving the use of a CO2 laser to engrave the microchannels on a paper substrate, followed by alkenyl ketene dimer treatment to hydrophobize the paper and lamination. The microchannel down to a minimum depth of ∼80 μm with an average roughness of ∼8 μm was engraved on the substrate. As a proof of concept, the applicability of this system to enrich the microparticles based on the inertial focusing mechanism was tested. This new generation of paper-based microfluidic system can be potentially used for the diagnostic applications where the analyte is low in quantity and processing a large volume of fluid sample is required.

Piezoresistive disposable weight sensor with increased sensitivity

This study presents the design, simulation, implementation, and experimental characterization of a paperbased perforated disposable weight sensor system with a double piezoresistive layer. The demonstrated system is designed to achieve highly sensitive weight sensing operations with low-cost materials. For that purpose, the main fabrication material of the proposed disposable sensor is selected as a 289 $\mu$m thick Strathmore 400 series Bristol paper. Approximately 48 $\mu$m thick piezoresistive graphite paste is coated onto both sides of the paper-based cantilever beam with the aim of acquiring more sensitive weight-sensing capability. Additionally, the proposed paper-based structure has rows of closely spaced perforations at prespecified locations to facilitate the bending of the cantilever beam and to further increase the sensitivity of the system. A peripheral electronic read-out circuitry is developed and integrated into the system. It is experimentally demonstrated that the proposed weight-sensing system can measure miniature weights ranging to 2 g with a resolution of 20 mg. The implemented sensor has a sensitivity of 17.13 mV/mN or 168.01 mV/g. Key words: This study presents the design, simulation, implementation, and experimental characterization of a paperbased perforated disposable weight sensor system with a double piezoresistive layer. The demonstrated system is designed to achieve highly sensitive weight sensing operations with low-cost materials. For that purpose, the main fabrication material of the proposed disposable sensor is selected as a 289$\mu$m thick Strathmore 400 series Bristol paper. Approximately 48 $\mu$m thick piezoresistive graphite paste is coated onto both sides of the paper based cantilever beam with the aim of acquiring more sensitive weight-sensing capability. Additionally, the proposed paper-based structure has rows of closely spaced perforations at prespecified locations to facilitate the bending of the cantilever beam and to further increase the sensitivity of the system. A peripheral electronic read-out circuitry is developed and integrated into the system. It is experimentally demonstrated that the proposed weight-sensing system can measure miniature weights ranging to 2 g with a resolution of 20 mg. The implemented sensor has a sensitivity of 17.13 mV/mN or 168.01 mV/g.

Life cycle assessment of a disposable and a reusable surgery instrument set for spinal fusion surgeries

The worldwide increasing wealth and increased life expectancy of humans has led to an increase in the number of medical procedures and surgeries. Surgeries are complex medical procedures which contribute to a significant share of the total environmental impact of the healthcare system. Among other important sources of environmental impacts from surgeries, material consumption due to required instrumentation accounts for up to 65 % of greenhouse gas emissions from surgeries. This study investigates how a disposable and a reusable surgery instrument sets for lumbar fusion surgeries contribute to the environmental impact and which system is more advantageous for the environment. For lumbar fusion surgeries, reusable and disposable instrumentation and implant sets are commercially available. Both sets are capable to support a one level lumbar fusion surgery. The reusable set is comprehensive and fully opened before the surgery, while the disposable system comes in a modular box system, and the boxes are opened on demand during the surgery. To compare the environmental impact of these different configurations, a comparative Life Cycle Assessment (LCA) was performed to assess the overall environmental impacts of both alternatives. One of the key findings is that the selected cleaning and sterilization process for reusable instruments is responsible for up to 90 % of the greenhouse gas emissions and decides which system is advantageous from an environmental perspective. Reducing the number of instruments to be cleaned and sterilized for a surgery should be the focus for future surgery instruments development from an environmental perspective.

Accuracy in osteotomy drilling using a new universal and disposable drill-stop device for dental implant drills: an in vitro study using a bovine rib model.

This study aimed to evaluate the surgical accuracy of a new universal disposable stop system for implant drills (FCA Universal Drill Stop). A total of 60 bovine ribs were included in this in vitro study. The ribs were randomized into three study groups (n=20 ribs per group). In each study group (Group1: drills without stop or control group, Group 2: prefabricated drills with stop or gold standard group, and Group 3: drills with FCA Universal Drill Stop) a total of 100 osteotomies were performed with implant drills in each group, following the drilling sequence for the placement of a dental implant of 10 mm length and 4 mm diameter. The accuracy of the depth of the osteotomies was quantified clinically (with periodontal probe) and radiologically, using ImageJ version 1.48v software. The order of highest to lowest accuracy (clinical and radiological) in the depth of osteotomies was: FCA Universal Drill Stop> prefabricated drills with a stop>drills without stop, with statistically significant differences being observed between both systems with stop with respect to the control group, although not between them. The new universal disposable stop system for implant drills, offers similar accuracy to prefabricated drills with stop, with both systems being much more accurate than implant drills without stop. Although this experimental evaluation showed favourable results, further clinical studies are necessary.

Molecular imprinted polymer based electrochemical sensor for selective detection of paraben

A new, simple, rapid, sensitive and selective disposable sensor platform was developed for the electrochemical detection of paraben based on molecular imprinting technique. Highly selective and specific recognition was established for the analyte through incorporating amino acid based polymerizable functional monomer. Paraben-imprinted poly-(2-hydroxyethyl methacrylate-N-methacryloyl-L-phenylalanine) (PHEMA-MAPA) nanofilm on a screen-printed gold electrode surface in the presence of polyvinyl alcohol (PVA) was synthesized by the molecular imprinting technique. Characterization of the fabricated electrode surfaces were performed with cyclic voltammetry (CV), atomic force microscopy (AFM) and attenuated total reflection fourier transform infrared spectrophotometry (ATR FT-IR). The electrochemical behavior of paraben was investigated using CV and electrochemical detection studies were carried out with square wave voltammetry (SWV). Under optimal conditions, the linear working range was found to be 1–30 μM with a low detection limit as 0.706 μM. The obtained recovery values proved that the developed sensor can be effectively applied to cosmetic samples. Besides, the fabricated disposable sensor system can be used successfully in the determination of other important analytes in the future due to its good sensor performance.

LEA 5. Use of Disposable Negative Pressure Wound Therapy on Split-Thickness Skin Graft Recipient Sites for Peripheral Artery Disease Foot Wounds—Two Case Reports

Negative pressure wound therapy (NPWT) is a popular and effective adjunct treatment for a great variety of wounds including split-thickness skin graft (STSG). Studies have concluded that NPWT improves STSG uptake. Recent technologic advancements have led to the advent of a new generation of NPWTs. These are the disposable, ultraportable, and mechanically operated NPWTs designed to treat smaller wounds with low to moderate exudates. We report here a novel use of the disposable NPWT (SNAP Therapy System; KCI, San Antonio, Tex) for STSG recipient sites in two patients with peripheral artery disease foot wounds. In both patients, there was 100% STSG uptake. The lightweight disposable NPWT system made for a more cost-effective and comfortable experience for patients. Disposable NPWT may be a feasible alternative to conventional NPWT to aid with STSG uptake for peripheral artery disease foot wound recipient sites.

The Reincarnation of Methoxyflurane

Methoxyflurane was an inhaled agent commonly used for general anesthesia in the 1960s, but its clinical role gradually decreased in the 1970s because of reports of dose-dependent nephrotoxicity. In 1999 its manufacturer, Abbott Laboratories, discontinued distribution of methoxyflurane in the United States and Canada. Outside of North America, however, methoxyflurane has been reborn as an inhaled analgesic used for pain relief in the prehospital setting and for minor surgical procedures. First used in Australia and New Zealand, and subsequently in over thirty-seven other countries, low concentrations of methoxyflurane are administered with a hand-held inhaler which provides conscious sedation, so that patients can self-assess their level of pain and control the amount of inhaled agent. The Penthrox inhaler, originally developed in Australia after several other hand-held vaporizers were tried, is currently being used worldwide as a portable and disposable self-administered agent delivery system. Methoxyflurane-induced nephrotoxicity continues to be a major concern, but with cautious administration of recommended doses methoxyflurane has been established as a remarkably safe analgesic agent with minimal side effects for patients in need of rapid and potent pain relief.

Evaluation of the accuracy of acetabular cup orientation using the accelerometer-based portable navigation system

BackgroundAccurate orientation of acetabular and femoral components is important during total hip arthroplasty (THA). In recent years, several navigation systems have been developed. However, these navigation systems for THA are unpopular worldwide because of their high cost. We assessed the orientation accuracy of cups inserted using a disposable accelerometer-based portable navigation system for THAs. MethodsThis was a prospective cohort study. We analyzed 63 hips with navigation prospectively and 30 hips without navigation retrospectively as historical control. The patients underwent THA via the mini anterolateral approach in the supine position using an accelerometer-based portable navigation system. We compared the preoperative target angles, intraoperative cup angles using navigation records, postoperative angles using postoperative CT data, measurement errors of cup angles, and clinical parameters such as sex, treated side, age at surgery, and body mass index (BMI). ResultsThe average absolute error (postoperative CT-navigation record) was 2.7 ± 2.1° (inclination) and 2.7 ± 1.8° (anteversion), and the absolute error (postoperative CT-preoperative target angle) was 2.6 ± 1.9° (inclination) and 2.7 ± 2.2° (anteversion). The absolute error between postoperative CT and target angle with navigation was significantly lower than the error without navigation (inclination; p = 0.025, anteversion; p = 0.005). Cup malalignment (absolute difference of inclination or anteversion between postoperative CT and preoperative target angle of over 5°) was significantly associated with BMI value (OR: 1.3, 95% CI: 1.1–1.7). The absolute measurement error of cup inclination and anteversion was significantly correlated with patients’ BMI (inclination error: correlation coefficient = 0.53, p < 0.001, anteversion error: correlation coefficient = 0.58, p < 0.001). ConclusionsThe clinical accuracy of accelerometer-based portable navigation is precise for the orientation of cup placement, although accurate cup placement was affected by high BMI. This is the first study to report the accuracy of accelerometer-based portable navigation for THA in the supine position.

Design of novel, simple, and inexpensive 3D printing-based miniaturized electrochemical platform containing embedded disposable detector for analytical applications.

This paper describes the development of a novel, simple, and inexpensive electrochemical device containing an integrated and disposable three-electrode system for detection. The base of this platform consists on a PDMS structure containing microchannels which were prototyped using 3D-printed molds. Pencil graphite leads were inserted into these microchannels and utilized as working, counter and reference electrodes in a novel design. Morphological analysis and electrochemical experiments with benchmark redox probes were carried out in order to evaluate the performance and characterize the miniaturized device proposed. Even using inexpensive materials and a simple fabrication protocol, the electrochemical platform developed provided good repeatability and reproducibility over a low cost (ca. $2 per device), acceptable lifetime (ca. 250 voltammetric runs) and extremely reduced consumption of samples and reagents (order of µL). As proof of concept, the analytical feasibility of the platform was investigated through the simultaneous determination of dopamine (DOPA) and acetaminophen (AC). The two analytes showed linear dependence on the concentration range from 1 to 15µM and the LODs achieved were 0.21µM for DOPA and 0.29µM for AC. Moreover, the platform was successfully applied on the determination of DOPA and AC in spiked blood serum and urine samples. The results obtained with the device described here were better than some reports in literature that use more costly electrodic materials and complex modification steps for the detection of the same analytes.

A Passive Microfluidic Device for Chemotaxis Studies.

This work presents a disposable passive microfluidic system, allowing chemotaxis studies, through the generation of a concentration gradient. The device can handle liquid flows without an external supply of pressure or electric gradients, but simply using gravity force. It is able to ensure flow rates of 10 µL/h decreasing linearly with 2.5% in 24 h. The device is made of poly(methylmethacrylate) (PMMA), a biocompatible material, and it is fabricated by micro-milling and solvent assisted bonding. It is assembled into a mini incubator, designed properly for cell biology studies in passive microfluidic devices, which provides control of temperature and humidity levels, a contamination-free environment for cells with air and 5% of CO2. Furthermore, the mini incubator can be mounted on standard inverted optical microscopes. By using our microfluidic device integrated into the mini incubator, we are able to evaluate and follow in real-time the migration of any cell line to a chemotactic agent. The device is validated by showing cell migration at a rate of 0.36 µm/min, comparable with the rates present in scientific literature.

Accuracy of cup orientation and learning curve of the accelerometer-based portable navigation system for total hip arthroplasty in the supine position

To assess the accuracy of cup orientation and learning curve of the disposable accelerometer-based portable navigation system for total hip arthroplasty (THA) in the supine position. A total of 75 patients who underwent THA through the anterolateral supine approach (ALS) with an accelerometer-based portable navigation system for the supine position (HipAlign®) between July 2017 and October 2018 were analyzed in this study. We compared the intraoperative cup angles using navigation records with the postoperative angles using postoperative computed tomography (CT) data. All patients were categorized into the following groups according to the course of three discrete, sequential operative time periods: 1-25 (initial group), 26-50 (intermediate group), and 51-75 (recent group). We compared the accuracy of cup inclination and anteversion among the three groups. The time required for navigation and the operative time of all patients were measured. The average absolute error in measurement (postoperative CT-navigation record) was 2.6° ± 2.7° (inclination) and 2.8° ± 2.7° (anteversion). There were no significant differences among the three groups. The average time required for navigation and the operative time were 365.1 ± 90.3 s and 76.1 ± 1.6 min, respectively. The required time for HipAlign® navigation and operative time were constant in most patients, except for those of the initial five cases. The accelerometer-based portable navigation system provides good accuracy of cup orientation, has a short learning curve, and requires a minimal surgical time for THA in supine position.

Ionic Liquid-Modified Disposable Electrochemical Sensor Strip for Analysis of Fentanyl.

The increasing prevalence of fentanyl and its analogues as contaminating materials in illicit drug products presents a major hazard to first responder and law enforcement communities. Electrochemical techniques have the potential to provide critical information to these personnel via rapid, facile field detection of these materials. Here we demonstrate the use of cyclic square wave voltammetry (CSWV) with screen-printed carbon electrodes (SPCE), modified with the room temperature ionic liquid (RTIL) 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide [C4C1pyrr][NTf2], toward such rapid "on-the-spot" fentanyl detection. This CSWV-based disposable sensor strip system provides an information-rich electrochemical fingerprint of fentanyl, composed of an initial oxidation event at +0.556 V (vs Ag/AgCl) and a reversible reduction and oxidation reaction at -0.235 and -0.227 V, respectively. The combined current and potential characteristics of these anodic and cathodic fentanyl peaks, generated using two CSWV cycles, thus lead to a distinct electrochemical signature. This CSWV profile facilitates rapid (1 min) identification of the target opioid at micromolar concentrations in the presence of other cutting agents commonly found in illicit drug formulations. The new protocol thus holds considerable promise for rapid decentralized fentanyl detection at the "point of need".

A Facile Electrochemical Sensor Labeled by Ferrocenoyl Cysteine Conjugate for the Detection of Nitrite in Pickle Juice.

Simple and facile electrochemical sensors for nitrite detection were fabricated by directly depositing ferrocenoyl cysteine conjugates Fc[CO-Cys(Trt)-OMe]2 [Fc(Cys)2] or Fc[CO-Glu-Cys-Gly-OH] [Fc-ECG] on screen-printed electrodes (SPEs). The modified carbon electrodes were characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Results indicated that Fc-ECG/SPE sensor showed enhanced current response and a lower overpotential than Fc(Cys)2/SPE sensor for nitrite detection. Optimal operating conditions were estimated for nitrite detection by DPV. The concentration of nitrite showed a good linear relationship with the current response in the range of 1.0–50 μmol·L−1 and with 0.3 μmol·L−1 as the concentration for limit of detection. There were no interferences from most common ions. The development of this electrochemical sensor was used for nitrite detection in pickled juice with a R.S.D. lower than 2.1% and average recovery lower than 101.5%, which indicated that disposable electrochemical sensor system can be applied for rapid and precise nitrite detection in foods.

Safety analysis and results of a borosilicate glass cartridge for no-touch graft loading and injection in Descemet membrane endothelial keratoplasty.

The aim of this study was to investigate the clinical outcome after standardized DMEK using a glass injector. A total of 254 patients undergoing DMEK surgery using a disposable DMEK borosilicate glass cartridge system were included in this retrospective study. The mean follow-up time was 13.2months (SD ± 8.1, range 6-36months). The used glass cartridge system has an aperture diameter of 1.6mm and a posterior loading orifice of 4.29mm. Scanning electron microscopy (SEM) was used for estimation of the surface relief of the glass cartridge and comparison with a standard plastic injector cartridge. Mean endothelial cell count of donor grafts was 2465 cells/mm2 (SD ± 199). After 6weeks of DMEK endothelial cell count decreased by - 28.6% to 1759 cells/mm2 (SD ± 435) (Wilcoxon p = 0.001) and remained stable at the final follow-up at 1735 cells/mm2 (SD ± 442) (Wilcoxon p = 0.89). SEM showed smoother surface of the glass cartridge in comparison with a plastic cartridge. This study showed that this simple and effective DMEK cartridge seems to be a safe and viable device for minimized graft manipulation during DMEK surgery.