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MODS, an assay for diagnosis of tuberculosis and drug-susceptibility, is based in the microscopic observation of the characteristic cords of Mycobacterium tuberculosis colonies grown in liquid media. An inverted optical microscope (100× magnification) is required to observe and interpret MODS cultures. Unfortunately, the cost of commercial inverted microscopes is not affordable in low resource settings. To perform a diagnosis of tuberculosis using the MODS assay, images with modest quality are enough for proper interpretation. Therefore, the use of a high cost commercial inverted optical microscope is not indispensable. In this study, we designed a prototype of an optical inverted microscope created by 3D-printing and based on a smartphone. The system was evaluated with 226 MODS TB positive and 207 MODS TB negative digital images. These images were obtained from 10 sputum samples MODS positive and 10 sputum samples MODS negative. The quality of all images was assessed by a qualified technician, in terms of adequacy to interpret and classify them as positive or negative for tuberculosis. The quality of the images was considered appropriate for MODS interpretation. All the 20 samples were correctly classified (as TB positive/negative) by reading with the prototype 3D-printed inverted microscope.

BackgroundThe MODS is an important assay for early diagnosis of tuberculosis and drug susceptibility. MODS is based in the microscopic observation, underneath, of the characteristic cords of Mycobacterium tuberculosis colonies grown in liquid media. An inverted optical microscope is required to observe and interpret MODS cultures. Unfortunately, the cost of commercial inverted microscopes is not affordable in low resource settings in developing countries.MethodologyTo perform a diagnosis of tuberculosis using the MODS assay, images with modest quality are enough for proper interpretation. Therefore, the use of a high cost commercial inverted optical microscope is not indispensable. In this study, we designed a prototype of an optical inverted microscope created with a 3D printer and based on a smartphone. The system was evaluated by comparison of manual interpretations of 226 TB positive MODS culture images and 207 negative MODS culture images.SignificanceThe prototype resulted in a low-cost inverted optical microscope, with simple functioning, and whose parts have been manufactured using 3D printing techniques. The quality of the images was good enough and achieved a 100% concordance between the manual inspection with the developed microscope, and the standard diagnostics of MODS.

The present work develops a MOS-based e-nose with sensors modified with zeolite Y. For this purpose, the following SnO2 doped with Pd and/or Pt have been prepared: M1 ((0.25 Pd/0.75 Pt)/SnO2), M2 ((0.50 Pd/0.50 Pt)/SnO2), M3 ((0.75 Pd/0.25 Pt)/SnO2), Pd/SnO2, and Pt/SnO2, at the total concentrations of the noble metals of 0.1% and 0.2% for use in gas sensors and be part of the electronic nose. Then, the sensors were assembled with the oxides using the screen printing method. Different electronic noses of four sensors were prepared by combining tin oxides doped with palladium and/or platinum and zeolite Y. The physicochemical characterization of oxides using FRX, FTIR, sorption of N2, and RAMAN has been performed. Measurements for the detection of wine volatile compounds such as ethanol, methanol, 1-phenyl ethanol, propionic acid, and acetic acid were carried out with these sensors located in a gas chamber and using a program that includes the Labview software, which serves to automate the sensing process. It was found that the sensors modified with zeolite were the ones that in general had higher detections of volatile compounds and PCAs showed positive correlations only for ethanol and the mixture of ethanol at 12% and methanol at 3%. This is related to better detection of these sensors.

Modern cell phones are a ubiquitous resource with a residual capacity to accommodate chemical sensing and biosensing capabilities. From the different approaches explored to capitalize on such resource, the use of autonomous disposable lab-on-a-chip (LOC) devices conceived as only accessories to complement cell phones underscores the possibility to entirely retain cell phones ubiquity for distributed biosensing. The technology and principles exploited for autonomous LOC devices are here selected and reviewed focusing on their potential to serve cell phone readout configurations. Together with this requirement, the central aspects of cell phones resources that determine their potential for analytical detection are examined. The conversion of these LOC concepts into universal architectures that are readable on unaccessorized phones is discussed within this context. (C) 2015 Elsevier B.V. All rights reserved. Funding Agencies|Swedish Research Council (VR) [C0453801]; Carl Tryggers Foundation [CTS14140]

A disposable device for quantitative enzymatic detection capable of coupling illumination and image readouts from cell phones is demonstrated. The device integrates a calibration range for glutamate detection, utilizes the phone screen as a light source, and provides the necessary actuation for autonomous operation. Custom made optics required to couple to the cell phone camera is accomplished using affordable stereolithography (SLA) 3D printers. The described method does not involve polishing, requires only two steps from design to implementation, and can be locally applied to 3D printed lab-on-a-chip (LOC) prototypes, using the same materials. Optical finishing and dimensional variability within 2% were achieved, supporting entirely arbitrary geometries for elements larger than 400 μm in radius. Representative fabrication times and costs were 20 min and $0.50 USD per prototype.

The unibody lab-on-a-chip (ULOC) concept entails a fast and affordable micro-prototyping system built around a single monolithic 3D printed element (unibody). A consumer-grade stereo lithography (SL) 3D printer can configure ULOCs with different forms of sample delivery, transport, handling and readout, while minimizing material costs and fabrication time. ULOC centralizes all complex fabrication procedures and replaces the need for clean room resources, delivering prototypes for less than 1 US$, which can be printed in 10 min and ready for testing in less than 30 min. Recent examples of ULOC integration of transport, chemical sensing for optical readout and flow mixing capabilities are discussed, as well as the integration of the first check-valves for ULOC devices. ULOC valves are strictly unidirectional up to 100 psi, show an exponential forward flow behavior up to 70 psi and can be entirely fabricated with the ULOC approach. Funding Agencies|Swedish Research Council (Vetenskapsradet); Carl Tryggers Foundation

Introduction: Tuberculosis (TB) is a significant cause of morbidity and mortality worldwide. The patient compliance with the long treatment regimens is essential for successful eradication. Pyrazinamide (PZA) shortens these regimens from 9 to 6 months, and therefore, improves treatment completion rates. Although PZA is a first-line medication for the treatment of TB, no simple or reliable assay to determine PZA resistance is yet available. In the presence of PZA, only susceptible Mycobacterium tuberculosis strains release pyrazinoic acid (POA). Therefore, the measurement and quantification of released POA is an indicator of PZA resistance. Methods: Two electrochemical sensors were constructed and tested with alternative working electrodes in conjunction with a portable potentiostat to measure the current produced when a potential difference of 2 V is applied to varying concentrations of POA in controlled solutions. Results: The large (13.2 mm) electrochemical sensor was able to detect POA at a minimum concentration of 40 μM to a statistically significant level (P = 0.0190). Similar graphical trends were obtained when testing the electrochemical sensor in the supernatant of a negative microscopic observation drug susceptibility assay culture, irrespective of the presence of PZA. Conclusion: Inexpensive and reusable electrochemical sensors with a portable potentiostat are a promising tool for the detection of POA, a biomarker of PZA susceptible M. Tuberculosis.

Background In Peru, tuberculosis (TB) is perceived as a nutritional disease. This perception, alongside factors including household food insecurity, may drive the food choices of people with TB and influence treatment outcomes. Objectives The objective of this qualitative study was to explore drivers of food choice among adults recently diagnosed with TB. Methods The study was conducted between April and December 2016 in the Huaycán district of Lima, Peru. Structured questionnaires were administered to 39 adults with TB at the time of diagnosis and after 1 mo of treatment to characterize food security and socioeconomic status. At 1 mo of treatment, 24-h dietary recalls, enhanced by recipes obtained from local street vendors, were administered to examine patterns of food consumption and determine mean daily intake of macro- and micronutrients. Among a subset of 9 participants, in-depth interviews were used to explore dietary beliefs and food choices associated with TB. Results Overall, 13.2% of participants were underweight at baseline, and 10.5% were overweight. At 1 mo of treatment, the mean caloric intake was 600 kcal/d over what was needed to maintain their current weight. Most of these additional kilocalories came from carbohydrates. Patients made active efforts to improve their diets during treatment, and were both receptive to, and actively sought out, nutritional advice. However, many patients reported significant unnecessary spending on questionable commercial products, such as expensive natural remedies and nutritional supplements. Conclusions The perceived connection between TB and diet creates both opportunities and challenges for treatment providers. Nutritional counseling provided through the national TB program should promote dietary quality through foods that are locally available, inexpensive, and aligned with cultural perceptions of health and wellness.

Digital manufacturing (DM) offers fast prototyping capabilities and great versatility to configure countless architectures at affordable development costs. Autonomous lab-on-a-chip (LOC) devices, conceived as only disposable accessory to interface chemical sensing to cell phones, require specific features that can be achieved using DM techniques. Here we describe stereo-lithography 3D printing (SLA) of optical components and unibody-LOC (ULOC) devices using consumer grade printers. ULOC devices integrate actuation in the form of check-valves and finger pumps, as well as the calibration range required for quantitative detection. Coupling to phone camera readout depends on the detection approach, and includes different types of optical components. Optical surfaces can be locally configured with a simple polishing-free post-processing step, and the representative costs are 0.5 US$/device, same as ULOC devices, both involving fabrication times of about 20 min.

Summary In this work, an automated microscopic observation drug susceptibility (MODS) plate reader has been developed. The reader automatically handles MODS plates and after autofocussing digital images are acquired of the characteristic microscopic cording structures of Mycobacterium tuberculosis, which are the identification method utilized in the MODS technique to detect tuberculosis and multidrug resistant tuberculosis. In conventional MODS, trained technicians manually move the MODS plate on the stage of an inverted microscope while trying to locate and focus upon the characteristic microscopic cording colonies. In centres with high tuberculosis diagnostic demand, sufficient time may not be available to adequately examine all cultures. An automated reader would reduce labour time and the handling of M. tuberculosis cultures by laboratory personnel. Two hundred MODS culture images (100 from tuberculosis positive and 100 from tuberculosis negative sputum samples confirmed by a standard MODS reading using a commercial microscope) were acquired randomly using the automated MODS plate reader. A specialist analysed these digital images with the help of a personal computer and designated them as M. tuberculosis present or absent. The specialist considered four images insufficiently clear to permit a definitive reading. The readings from the 196 valid images resulted in a 100% agreement with the conventional nonautomated standard reading. The automated MODS plate reader combined with open-source MODS pattern recognition software provides a novel platform for high throughput automated tuberculosis diagnosis.

A portable water analyzer based on a voltammetric electronic tongue has been developed. The system uses an electrochemical cell with two working electrodes as sensors, a computer controlled potentiostat, and software based on multivariate data analysis for pattern recognition. The system is suitable to differentiate laboratory made and real in-situ river water samples contaminated with different amounts of Escherichia coli. This bacteria is not only one of the main indicators for water quality, but also a main concern for public health, affecting especially people living in high-burden, resource-limiting settings.

El objetivo principal fue encontrar cómo ciertos parámetros o factores fisicoquímicos del carbón activado pueden influir en la capacidad de adsorción de tres adsorbatos: fenol, ácido benzoico y ácido salicílico. Se emplearon dos métodos de análisis multivariado de datos: análisis principal de mínimos cuadrados (PLS) y regresión de componentes principales (PCR). El método de PLS mostró una mejor concordancia entre los valores estimados y experimentales. Usando este método, se formularon ecuaciones para predecir la capacidad de remoción de cada adsorbato. Usando PLS fue posible estimar la capacidad de adsorción del ácido benzoico, ácido salicílico y fenol con un error estándar de validación menor al 6%. Así se predijo que la acidez superficial es el parámetro más importante del carbón activado para adsorber compuestos aromáticos. The main objective was to describe parameters and physicochemical factors of activated carbon related to the adsorption capacity of three adsorbates: Phenol, benzoic acid, and salicylic acid. Two multivariate data analysis methods were used: Partial least square (PLS) and principal component regression (PCR). PLS showed better agreement between estimated and experimental values and using this method, equations were developed to predict the removal capacity of each adsorbate. The adsorption capacity of activated carbon in relation to benzoic acid, salicylic acid, and phenol was predicted with a standard error of validation of less than 6%. Surface acidity was the most important parameter affecting the adsorption of aromatic compounds by activated carbon.

Exploiting the ubiquity of cell phones for quantitative chemical sensing imposes strong demands on interfacing devices. They should be autonomous, disposable, and integrate all necessary calibration and actuation elements. In addition, a single design should couple universally to a variety of cell phones, and operate in their default configuration. Here, we demonstrate such a concept and its implementation as a quantitative glucose meter that integrates finger pumps, unidirectional valves, calibration references, and focusing optics on a disposable device configured for universal video acquisition.

The characterization of opaque color samples using reflected light is demonstrated with a computer screen photo-assisted technique (CSPT). CSPT utilizes standard computer screens as light sources and conventional web cameras as detectors to perform colorimetric or fluorescent evaluations that retain key spectral features of the tested substances. In this work, the fingerprinting of samples spectral reflectances is achieved by evaluating the reflected light under controlled computer screen illumination. Two different methods for processing of features are investigated, revealing complementary properties for classifications purposes. The attainable classification enables to distinguish different colors from just hues of a same color.

In situ thin film thickness monitoring and profilometering was implemented for a spray pyrolysis deposition technique, based on measuring the reflection of a laser beam from the film–substrate system; the interference pattern obtained during film deposition was used to calculate the film thickness. Recording in situ the reflection pattern for points separated 0.5 cm along the film allowed the film profile to be obtained. The growth of pyrolitic ZnO film on glass was studied by this method. It was found that the in situ measured thickness is in good agreement with that measured by ex situ profilometering or scanning electron microscopy (SEM). SEM micrographs of the films showed that the surface is formed by elongated-shaped particles, which become rounded and larger in size as the film becomes thicker. This fact was correlated with an increment of the diffuse component of the optical spectral reflectance and transmittance and with the trend of the surface roughness factor, obtained in situ.

Versatile prototyping of 3D printed lab-on-a-chip devices, supporting different forms of sample delivery, transport, functionalization and readout, is demonstrated with a consumer grade printer, which centralizes all critical fabrication tasks. Devices cost 0.57US$ and are demonstrated in chemical sensing and micromixing examples, which exploit established principles from reference technologies.

The fabrication of conventional PDMS on glass lab-on-a-chip (LOC) devices, using templates printed with a commercial (2299 US$) micro-stereo lithography 3D printer, is demonstrated. Printed templates replace clean room and photolithographic fabrication resources and deliver resolutions of 50 μm, and up to 10 μm in localized hindrances, whereas the templates are smooth enough to allow direct transfer and proper sealing to glass substrates. 3D printed templates accommodate multiple thicknesses, from 50 μm up to several mm within the same template, with no additional processing cost or effort. This capability is exploited to integrate silicone tubing easily, to improve micromixer performance and to produce multilevel fluidics with simple access to independent functional surfaces, which is illustrated by time-resolved glucose detection. The templates are reusable, can be fabricated in under 20 min, with an average cost of 0.48 US$, which promotes broader access to established LOC configurations with minimal fabrication requirements, relieves LOC fabrication from design skills and provides a versatile LOC development platform.

In regions of the world where tuberculosis (TB) poses the greatest disease burden, the lack of access to skilled laboratories is a significant problem. A lab-free method for assessing patient recovery during treatment would be of great benefit, particularly for identifying patients who may have drug-resistant tuberculosis. We hypothesize that cough analysis may provide such a test. In this paper we describe algorithm development in support of a pilot study of TB patient coughing. We describe several approaches to event detection and classification, and show preliminary data which suggest that cough count decreases after the start of treatment in drug-responsive patients. Our eventual goal is development of a low-cost ambulatory cough analysis system that will help identify patients with drug-resistant tuberculosis.

Background A laboratory-free test for assessing recovery from pulmonary tuberculosis (TB) would be extremely beneficial in regions of the world where laboratory facilities are lacking. Our hypothesis is that analysis of cough sound recordings may provide such a test. In the current paper, we present validation of a cough analysis tool. Methodology/Principal Findings Cough data was collected from a cohort of TB patients in Lima, Peru and 25.5 hours of recordings were manually annotated by clinical staff. Analysis software was developed and validated by comparison to manual scoring. Because many patients cough in bursts, coughing was characterized in terms of cough epochs. Our software correctly detects 75.5% of cough episodes with a specificity of 99.6% (comparable to past results using the same definition) and a median false positive rate of 4 false positives/hour, due to the noisy, real-world nature of our dataset. We then manually review detected coughs to eliminate false positives, in effect using the algorithm as a pre-screening tool that reduces reviewing time to roughly 5% of the recording length. This cough analysis approach provides a foundation to support larger-scale studies of coughing rates over time for TB patients undergoing treatment.

BACKGROUND: The microscopic observation drug susceptibility (MODS) assay for rapid, low-cost detection of tuberculosis and multidrug resistant tuberculosis depends upon visualization of the characteristic cording colonies of Mycobacterium tuberculosis in liquid media. This has conventionally required an inverted light microscope in order to inspect the MODS culture plates from below. Few tuberculosis laboratories have this item and the capital cost of $5,000 for a high-end microscope could be a significant obstacle to MODS roll-out. METHODOLOGY: We hypothesized that the precise definition provided by costly high-specification inverted light microscopes might not be necessary for pattern recognition. SIGNIFICANCE: In this work we describe the development of a low-cost artesenal inverted microscope that can operate in both a standard or digital mode to effectively replace the expensive commercial inverted light microscope, and an integrated system that could permit a local and remote diagnosis of tuberculosis.

Se ha desarrollado un prototipo que puede monitorear la calidad del agua en tiempo real que esta basado en una “lengua electrónica”. El sistema esta basado en métodos electroquímicos y consiste en la combinación de varios sensores electroquímicos no selectivos (electrodos de metales), el procesamiento y tratamiento de las señales, y un algoritmo de reconocimiento de patrones. Patrones de respuestas únicos para las muestras liquidas son interpretados con un análisis de componentes principales. El sistema determina atributos (calidad, estado del proceso, etc.) antes que parámetros simples. El prototipo es portátil y ha evaluado la calidad del agua de consumo humano en una zona rural (Yaurisque, Cusco). El sistema ha logrado discriminar agua con diferentes composición química y bacteriológica., A prototype has been developed that could monitor the water quality in real time based on an “electronic tongue”. The system is based on electrochemical methods and involves the combination of non-selective sensors (metal electrodes), the signal processing part, and a pattern recognition. It determines attributes (quality, status of a process, etc.) rather than single parameters. Unique response patterns for liquid samples are interpreted with principal components analysis. The prototype is portable and has evaluated the water quality in a rural area (Yaurisque, Cusco). The system could discriminate water with different chemical and bacterological composition.

A laboratory-free test for assessing recovery from pulmonary tuberculosis (TB) would be very helpful in regions of the world where laboratory facilities are lacking. Our hypothesis is that analysis of cough sound recordings may provide such a test, as recovering patients should cough less frequently. We have carried out several studies on cough data from a cohort of TB patients in Lima, Peru [Larson et al., PLOS One]. Our previous work provides a foundation to support larger-scale studies of coughing rates over time for TB patients undergoing treatment, but it only used recordings from lapel microphones. For the current study, we use an additional channel recorded by a throat-mounted accelerometer. The accelerometer only responds to patient-generated noise events and thus provides robustness to background noise in the environment. We describe algorithm development for cough data analysis using combined microphone/accelerometer measurements, and compare several event detection and classification strategies...

In regions of the world where tuberculosis (TB) poses the greatest disease burden, clinicians often lack access to skilled laboratories. This is particularly problematic for patients with drug-resistant tuberculosis, as these patients will otherwise receive standard TB medication and will not respond to treatment. Thus, a lab-free method for assessing patient recovery during treatment would be of great benefit. We hypothesize that cough analysis may provide such a test, and have carried out a pilot study to record coughs from a cohort of patients in Lima, Peru. We describe algorithm development for cough data analysis and compare several event detection and classification strategies. Results from our ongoing validation efforts suggest that cough count (cough/hour) decreases noticeably after the start of treatment in drug-responsive patients. Our long-term goal is development of a low-cost ambulatory cough analysis system that will help identify patients with drug-resistant tuberculosis.