Cost-effective protocol to produce 3D-printed electrochemical devices using a 3D pen and lab-made filaments to ciprofloxacin sensing.

A novel conductive filament based on graphite (Gr) dispersed in polylactic acid polymer matrix (PLA) is described to produce 3D-electrochemical devices (Gr/PLA). This conductive filament was used to additively manufacture electrochemical sensors using the 3D pen. Thermogravimetric analysis confirmed that Gr was successfully incorporated into PLA, achieving a composite material (40:60% w/w, Gr and PLA, respectively), while Raman and scanning electron microscopy revealed the presence of defects and a high porosity on the electrode surface, which contributes to improved electrochemical performance. The 3D-printed Gr/PLA electrode provided a more favorable charge transfer (335 Ω) than the conventional glassy carbon (1277 Ω) and 3D-printed Proto-pasta® (3750 Ω) electrodes. As a proof of concept, the ciprofloxacin antibiotic, a species of multiple interest, was selected as a model molecule. Thus, a square wave voltammetry (SWV) method was proposed in the potential range + 0.9 to + 1.3 V (vs Ag|AgCl|KCl(sat)), which provided a wide linear working range (2 to 32 µmol L-1), 1.79 µmol L-1 limit of detection (LOD), suitable precision (RSD < 7.9%), and recovery values from 94 to 109% when applied to pharmaceutical and milk samples. Additionally, the sensor is free from the interference of other antibiotics routinely employed in veterinary practices. This device is disposable, cost-effective, feasibly produced in financially limited laboratories, and consequently promising for evaluation of other antibiotic species in routine applications.

New microfluidic paper-based analytical device for iron determination in urine samples.

Iron is an important micronutrient involved in several mechanisms in the human body and can be an important biomarker. In this work, a simple and disposable microfluidic paper-based analytical device (µPAD) was developed for the quantification of iron in urine samples. The detection was based on the colorimetric reaction between iron(II) and bathophenanthroline and the reduction of iron(III) to iron(II) with hydroxylamine. The developed µPAD enabled iron determination in the range 0.07-1.2 mg/L, with a limit of detection of 20 µg/L and a limit of quantification of 65 µg/L, thus suitable for the expected values in human urine. Additionally, targeting urine samples, the potential interference of the samples color was overcome by incorporating a sample blank assessment for absorbance subtraction. Stability studies revealed that the device was stable for 15 days prior to usage and that the formed colored product was stable for scanning up to 3 h. The accuracy of the developed device was established by analyzing urine samples (#26) with the developed µPAD and with the atomic absorption spectrometry method; the relative deviation between the two sets of results was below 9.5%.

A search for new options to manage fecal incontinence.

Fecal incontinence (FI) is a highly prevalent condition known to substantially impair a patient's quality of life. Although a non-invasive treatment option, currently available anal plugs are poorly tolerated, not significantly effective and therefore not often used. We present a new disposable device based on an innovative concept that renews the interest for non-invasive "external" control of bowel content for FI patients. The Contix™ (Forconti Medical Ltd, Cesarea, Israel) permits creation of temporary "artificial" fecal impaction to avoid bowel leakage while inserted high into the "non sensitive" rectum where it is not felt by the patient and therefore tolerated for 6- to 12- hour use. This European conformity (CE)-marked device has a unique design that allows insertion, usage and removal in a similar manner to a vaginal pad. It comes in 2 parts: a flexible silicone-based oval-shaped biocompatible balloon and an applicator in which the balloon is folded for self-insertion. An external tube allows for the balloon to be inflated with 60-100ml. of air. In doing this, small smooth tines deploy on its surface to help maintain the balloon in place. A pulling string with a ring stays out of the anal canal to deflate and withdraw the balloon inverted on itself at end of use. Device handling that includes rectal insertion and withdrawal feasibility, wear time, comfort at the different steps of use, safety and of course effectiveness of Contix™ have been tested in small trials yet to be published but pilot studies support its uses at greater scale in expert centers in Europe and the United States. In summary the Contix™ is a non-invasive device for FI management based on an innovative concept. Initial results support its spread to identify its role as an ancillary service to existing approaches.

Wide electrochemical window of screen-printed electrode for determination of rapamycin using ionic liquid/graphene composites.

A disposable screen-printed carbon electrode (SPCE) modified with an ionic liquid/graphene composite (IL/G) exhibits a wider potential window, excellent conductivity, and specific surface area for the improvement in the voltammetric signal of rapamycin detection. The modified composite was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). The electrochemical behavior of rapamycin at the modified SPCE was investigated by cyclic and square wave voltammetry in 60:40 EtOH: 0.1 M LiClO4 at pH 5.0. A high reproducible and well-defined peak with a high peak current were obtained for rapamycin detection at a position potential of + 0.98 V versus Ag/AgCl. Under the optimized conditions, the rapamycin concentration in the range 0.1 to 100 µM (R2 = 0.9986) had a good linear relation with the peak current. The detection limit of this method was 0.03 µM (3SD/slope). The proposed device can selectively detect rapamycin in the presence of commonly interfering compounds. Finally, the proposed method was successfully applied to determine rapamycin in urine and blood samples with excellent recoveries. These devices are disposable and cost-effective and might be used as an alternative tool for detecting rapamycin in biological samples and other biological compounds. Graphical abstract Schematic presentation of wide electrochemical window and disposable screen-printed sensor using ionic liquid/graphene composite for the determination of rapamycin. This composite can enhance the oxidation current and expand the potential for rapamycin detection.

Development of an Integrated Disposable Device for SARS-CoV-2 Nucleic Acid Extraction and Detection.

Objective: To develop a highly sensitive and rapid nucleic acid detection method for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Methods: We designed, developed, and manufactured an integrated disposable device for SARS-CoV-2 nucleic acid extraction and detection. The precision of the liquid transfer and temperature control was tested. A comparison between our device and a commercial kit for SARS-Cov-2 nucleic acid extraction was performed using real-time fluorescence reverse transcription polymerase chain reaction (RT-PCR). The entire process, from SARS-CoV-2 nucleic acid extraction to amplification, was evaluated. Results: The precision of the syringe transfer volume was 19.2 ± 1.9 µL (set value was 20), 32.2 ± 1.6 (set value was 30), and 57.2 ± 3.5 (set value was 60). Temperature control in the amplification tube was measured at 60.0 ± 0.0 °C (set value was 60) and 95.1 ± 0.2 °C (set value was 95) respectively. SARS-Cov-2 nucleic acid extraction yield through the device was 7.10 × 10 6 copies/mL, while a commercial kit yielded 2.98 × 10 6 copies/mL. The mean time to complete the entire assay, from SARS-CoV-2 nucleic acid extraction to amplification detection, was 36 min and 45 s. The detection limit for SARS-CoV-2 nucleic acid was 250 copies/mL. Conclusion: The integrated disposable devices may be used for SARS-CoV-2 Point-of-Care test (POCT).

Laparoscopic supracervical hysterectomy using EnSeal vs standard bipolar coagulation technique: randomized controlled trial.

OBJECTIVE: To compare the EnSeal device with standard bipolar coagulation forceps in laparoscopic supracervical hysterectomy (LASH). DESIGN: Prospective, randomized, controlled trial (Canadian Task Force classification I). SETTING: University hospital. PATIENTS: One hundred sixty patients who underwent LASH. INTERVENTION: Eighty patients underwent LASH using the EnSeal device (experimental group), and 80 patients underwent LASH using standard bipolar coagulation forceps (control group) (www.clinicaltrials.gov; study identifier NCT01806012). MEASUREMENTS AND MAIN RESULTS: Mean (SD) total operative time was 78.18 (33.96) minutes in the experimental group and 86.30 (35.34) minutes in the control group (p = .03). Documented blood loss was <50 mL in 72 patients in the experimental group and 62 patients in the control group (p = .03), and was 50 to 100 mL in 8 patients in the experimental group and 18 patients in the control group (p < .001). Postoperative hospital stay was significantly shorter for patients in the experimental group compared with the control group: 2.01 (0.44) days vs 2.17 (0.47) days, respectively (p = .03). There was no difference in postoperative pain scores and complications between the two treatment groups. CONCLUSION: Total resection time was shorter in the experimental group, and the other investigated clinical parameters were not inferior in the experimental group compared with the control group. The results of the present study indicate that use of the EnSeal device is at least as reliable as the conventional electrocoagulation technique in LASH.

Integrated calibration and serum iron in situ analysis into an array microfluidic paper-based analytical device with smartphone readout.

In this work, a colorimetric microfluidic paper-based analytical device (µPAD) combined with a smartphone readout was proposed for the determination of serum iron (Fe3+), which is linked to transferrin. Firstly, Fe3+ was selectively isolated and preconcentrated from serum by using anti-transferrin immunomagnetic beads (anti-Tf-MBs). Secondly, Fe3+ is reduced to Fe2+ by a hydroxylamine solution (pH 4.8) and then measured in the µPAD, which contains the colorimetric reagent ferrozine. Finally, the intensity of the purple color formed in the µPAD was measured by a smartphone. The approach exhibited an excellent linear correlation (r = 0.996) and good limit of detection (0.3 µg mL-1). Moreover, a certified reference material (human serum) was analyzed by this approach, showing an excellent accuracy (Er < 4%) and inter-device reproducibility (RSD = 1%, n = 3). Interestingly, the µPAD array-design allowed the simultaneous analysis of different samples, improving the sample throughput (up to 5 samples in 130 min, using 100 µL each), and the integration of calibration and analysis into the same device, simplifying the analysis without losing accuracy or sensitivity, and avoiding inter-device variability, which constituted an added value to this approach. These disposable µPADs meet several requirements of point-of-care testing (POCT) because it is cheap, portable, easy-to-use, sensitive, and specific. Therefore, it may be an interesting way for measuring patients' serum iron levels in situ with reliability, especially, in developing countries, where the prevalence of iron deficiency and iron-deficiency anemia is higher and there are lower health resources than in developed countries.

A simple micropump based on a freeze-dried superabsorbent polymer for multiplex solution processing in disposable devices.

We describe a simple micropump for disposable microfluidic devices. The pump is constructed using a freeze-dried disc of a superabsorbent polymer (SAP). The disc absorbs a solution in a flow channel and swells upward in a pumping chamber. Despite the simple structure of this device, the rate of absorption remains constant and can be adjusted by changing the composition of the SAP, its size, the dimensions of the flow channel and the medium to be absorbed. The pumping action can be initiated by applying an electrical signal using a switchable hydrophobic valve. The integrated approach of the SAP pump and switchable valve could facilitate the automatic processing of many solutions required for bioassay.