Smartphone Ambient Light Sensor Research Articles

Smartphone-assisted immunosensing of cancer biomarkers in human biofluids using poly (methyl methacrylate) decorated by triangular silver nanoparticles

This system utilizes an innovative platform consisting of a poly (methyl methacrylate) (PMMA) plate adorned with triangular silver nanoparticles, enabling the sensitive and specific detection of prostate-specific antigen (PSA), carcinoembryonic antigen (CEA), and cancer antigen 15–3 (CA 15.3). To achieve this, the PMMA polymer microarrays were precisely cut using a laser cutting machine to create an optimized number of micro-arrays. These designed wells were embellished with triangular silver nanoparticles (TA-AgNPs) featuring prism morphology. The antigens could be easily detected based on antigen–antibody-induced aggregation of TA-AgNPs and resulting in a visible color change due to the alteration of surface plasmon resonance properties. Consequently, utilizing the immunocomplex of antigen–antibody in the presence of the optical probe (TA-AgNPrs) and a portable photochemical sensor, candidate cancer biomarkers (PSA, CEA, and CA 15.3) were successfully identified with linear ranges of 1–60, 1–75, and 1–125 µg/mL, respectively. By employing digital image analysis using a smartphone, we achieved a highly favorable low limit of quantification of 1 µg/mL for PSA, CEA, and CA 15.3 as biomarkers for prostate, colon, and breast cancer, respectively. This groundbreaking research introduces a pioneering digital image-based colorimetry immunoassay, the first of its kind in the field, providing a transformative approach to the early-stage diagnosis of various cancer biomarkers through a single opto-device. To the best of our knowledge, no smartphone ambient light sensor has yet been specifically designed to identify PSA, CEA, and CA 15.3 proteins as cancer biomarkers. Therefore, a sensory micro-array was developed to open new possibilities for the rapid and simple colorimetric identification of PSA, CEA, and CA 15.3 antigens in real samples, offering a sensitive and specific monitoring strategy for these biomarkers through colorimetry.

A portable smartphone-based hemoglobin point-of-care testing platform for accurate anemia diagnostics

Anemia affects over 2 billion people worldwide, with the heaviest burden borne by women and children. At present, anemia is diagnosed by measuring hemoglobin (Hb) levels, which must be done in hospitals or commercial laboratories by skilled operators. In this work, we report a portable, affordable ($3), easy-to-operate (1 min) and accurate smartphone-based Hb analyzer (SHbA) that uses a drop of finger-pricked blood for anemia point-of-care test (POCT) applications. POCT of Hb was achieved using a smartphone ambient light sensor (ALS) to accurately measure the absorbance of colorimetric Hb biochemical analysis reagents in a microcuvette, as well as an Android-based application for results analysis. SHbA validation results agreed well with those reported by a hematology analyzer, and the SHbA has an anemia diagnosis sensitivity of 95.4% and specificity of 96.3% for venous blood (n = 360) and a sensitivity of 96.39% and specificity of 95.58% for fingertip blood (n = 475). In addition, SHbA exhibits excellent performance in the diagnosis and treatment guidance of anemia high-risk populations, including tumor chemotherapy patients (n = 424), pregnant women (n = 214) and thalassemia patients (n = 208). Importantly, volunteer self-testing results (n = 20) indicate that SHbA can be used for home-based anemia diagnosis and monitoring. SHbA has the advantages of high sensitivity and specificity while being cheap and easy to operate, making it widely applicable for the diagnosis and treatment of anemia, especially for high-risk patients in areas with poor medical resources.

Multifunctional 3D-printed platform integrated with a smartphone ambient light sensor for halocarbon contaminants monitoring

3D-printed platforms integrated with smartphone light sensors have become a powerful tool for the development of frugal and facile biosensing systems. Herein, we report a 3D-printed platform for multimodal analysis (3D-PMA) based on a smartphone ambient light sensor (ALS). The proposed approach was first validated using a microtiter plate reader, and then its application potential was demonstrated by measuring halohydrin dehalogenase activities employing three different sample modes, viz . using enzyme-linked immunosorbent assay (ELISA) plate strips, cuvettes, and the glass fiber membrane as sample containers. For real-sample analysis, 1,3-dichloro-2-propanol (1,3-DCP), a toxic halogenated compound, was successfully detected in spiked river water samples with recoveries in the range of 101.95–109.70%. After demonstrating the suitability for liquid-phase assays, the 3D-PMA was also optimized for 1,3-DCP detection using a glass fiber membrane. The detection could be done using a 10 μ L reaction system with an assay time of 2 min. The assay showed two linear ranges. The calibration equation of Y = 81.687x + 140.060 was obtained from the lower part of the calibration curve and was used to calculate the detection limit of the system. Under optimized conditions, a detection limit of 80 μ M was achieved for 1,3-DCP. The small size of the device endows it with great promise for use as a benchtop and an on-demand detection system. The proposed low-cost and portable system has great potential for the (bio) sensing of different biological and environmental samples where biocomponent-analyte interaction leads to a color change of the reaction system, indicating its applicability in resource-constrained settings. • A smartphone assisted portable system was developed for environmental contaminants monitoring. • 3D-printed platform demonstrated potential utility for multimodal analysis. • Smartphone Ambient Light Sensor as a potential transducer for halocarbon detection.

Determination of gravity acceleration with smartphone ambient light sensor

Among the serious experimental uses given to smartphones in physics, the use of integrated sensors, video analysis, and mixed uses as simultaneous material and instruments stand out for their frequency. Regarding the use of integrated sensors, there are many proposals that use the accelerometer, the magnetometer, or other sensors (e.g, camera or microphone) to find experimental values of physical constants, such as acceleration of gravity (g), thereby trying to contribute to the studies of statics, kinematics, and dynamics. However, there are few studies that use the ambient light sensor for this kind of purpose.

A smartphone-based multi-wavelength photometer for on-site detection of the liquid colorimetric assays for clinical biochemical analyses

A novel portable and cost-effective multi-wavelength smartphone colorimetric reader (MW-SCR) was designed for the quantitation of liquid colorimetric assays. Six light-emitting diodes (LEDs) with different wavelengths were assembled in a roulette fashion to form the light detection source. An ambient light sensor of smartphone was applied as the detector. Using this MW-SCR, we detected six common serum analytes, including alkaline phosphatase(ALP), potassium(K+), chloride(Cl−), alanine aminotransaminase(ALT), glycated serum protein(GSP), and albumin, to evaluate the feasibility and reliability of the MW-SCR. Strong linear regression (R2>0.99) analysis with a wide linear range and good limits of detection were found for this device, detection limits as low as 0.37 U/L, 0.0083 mmol/L, 0.78 mmol/L, 4.49 KarU, 0.023 mmol/L and 2.23 g/L for ALP, K+,Cl−, ALT, GSP and albumin, respectively, were achieved. It also had high repeatability that ranged from 0.20 to 0.61 % relative standard deviations (RSD), and the precision ranged of MW-SCR were from 0.26 to 1.17 % RSDs. Results demonstrated that our device showed remarkable stability, accuracy, and repeatability, presenting excellent consistency with a professional microplate reader. It can be redesigned for multiple indications, such as clinical biochemical analyses, food safety testing, environmental monitoring and so on, because it is open source, user friendly and easy manufacturing.

A smartphone-based enzyme-linked immunochromatographic sensor for rapid quantitative detection of carcinoembryonic antigen

The development and application of portable, cost-effective, and user-friendly biosensing technology to enable real-time disease diagnosis on the spot are alway a top priority in the in vitro diagnostic (IVD). Here, a smartphone based enzyme-linked immunochromatographic sensor (ELICS) system was developed as required. This hand-held sensing system utilizes built-in ambient light sensor in smartphone and integrated with a specially designed disposable chromatography device. Immunoassay and enzyme coloration are performed on the chromatography device to form a biosensor channel, and the results are read directly by the smartphone ambient light sensor. To demonstrate this platform, the commonly used cancer biomarker carcinoembryonic antigen (CEA) was chosen as a proof-of-concept test. This method was 100-folds more sensitive than conventional used immunochromatographic assay, and whole detection and analysis process was completed within 25 min. For detection of CEA in clinical serum samples, the ELICS results were well correlated with those from chemiluminescence immunoassay (CLIA). With the advantages of high sensitivity, rapid, user-friendly, low cost and portability, ELICS would have wide applicability in family and community medical institution, especially in the areas of poor medical resources.

Label-Free Colorimetric Detection of Urine Glucose Based on Color Fading Using Smartphone Ambient-Light Sensor

In this work, a label-free colorimetric assay was developed for the determination of urine glucose using smartphone ambient-light sensor (ALS). Using horseradish peroxidase—hydrogen peroxide—3,3′,5,5′-tetramethylbenzidine (HRP-H2O2-TMB) colored system, quantitative H2O2 was added to samples to-be-determined for deepest color. The presence of glucose oxidase in urine led to the formation of H2O2 and the reduction of TMBred. As a result of this, the color of the urine faded and the solution changed from deep blue to light blue. We measured the illuminance of the transmitted light by a smartphone ambient light sensor, and thereby color changes were used to calculate the content of urine glucose. After method validation, this colorimetric assay was practically applied for the determination of urine samples from diabetic patients. Good linearity was obtained in the range of 0.039–10.000 mg/mL (R2 = 0.998), and a limit of detection was 0.005 mg/mL. Our method was had high accuracy, sensitivity, simplicity, rapidity, and visualization, providing a new sensor to be potentially applicable for point-of-care detection of urine glucose.

A sample-to-answer quantitative platform for point-of-care testing of biochemical markers in whole blood

Point-of-care quantitative detection of biochemical markers has broad applications in resource-limited settings. However, current challenges including difficulty in sample preparation and limitation in result quantitation make point-of-care detection platforms failed to achieve fully sample-to-answer detection or meet the clinical quantitative demands. Here, we developed a novel point-of-care platform to realize fully sample-to-answer biochemical marker quantitation in whole blood. Our platform integrated a plasma separation module and a detection module. The plasma separation module contained a plasma separation strip could rapidly separate the plasma from whole blood samples by lateral flow. The detection module generated a colorimetric signal which could be quantified by the smartphone ambient light sensor (ALS) in an equipment-free manner. As a proof-of-concept, two hepatobiliary disease-associated markers, total bilirubin (TBil) and direct bilirubin (DBil), were detected from whole blood to quantitative result. The quantitative performance for clinical samples was highly consistent with the well-established clinical chemistry analyzer. Our platform exhibited remarkable advantages of significant portability (< 40 g), low cost (< $5), rapidity (< 5 min), instrument-free, high sensitivity (< 1 μM), and accuracy (89.5 % for TBil, 94.7 % for DBil), which showed up a great potential for biochemical markers detection in resource-limited settings.

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Spectrophotometry is a fundamental technique in many areas of science, with many applications and uses. The cost of spectrophotometers has acted as a barrier on the teaching and use of the technique. Here, we provide open-source plans to a 3D-printed cuvette holder with an interchangeable narrow–spectral bandwidth light-emitting diode (LED) block that can be used in conjunction with a smartphone’s ambient light sensor (ALS) to perform spectrophotometry. A Lego version with an interchangeable LED block is also presented. Results from the smartphone spectrophotometer in comparison with commercially available spectrophotometers demonstrated functionality, and the model may have many applications, especially in indirect spectrophotometry, such as in the protein assay shown here. The plans for the 3D-printed model are freely available on GitHub, as are editable files to allow customisation by users. We would encourage users to share adaptations with the scientific community.

A simple pendulum-based measurement of g with a smartphone light sensor

A quick and very accessible method for the measurement of acceleration due to gravity is presented. The experimental set-up employs a smartphone ambient light sensor as the motion timer for measuring the period of a simple pendulum. This allowed us to obtain an experimental value, 9.72 + 0.05 m s−2, for the gravitational acceleration which is in good agreement with the local theoretical value of 9.78 m s−2.

A dynamic-based measurement of a spring constant with a smartphone light sensor

An accessible smartphone-based experimental set-up for measuring a spring constant is presented. Using the smartphone ambient light sensor as the motion timer that allows for the measurement of the period of oscillations of a vertical spring-mass oscillator we found the spring constant to be 27.3 0.2 N m−1. This measurement is in a satisfactory agreement with another experimental value, 26.7 0.1 N m−1, obtained via the traditional static method.

Preliminary study of simple methods to get the average speed using a smartphone's light sensor

This paper reports on the result of a preliminary study of utilization of a smartphone ambient light sensor for get the average speeds of motion along a straight line based on experiments. We attach a smartphone to a dynamics train that travels across multiple light sources where the distance is already set. The main source of this experiment is obtained from the luminosity curve obtained from free android applications. From the curve, we can get position information against time. So from the data we can get the value of average speed. Then the use of the smartphone light sensor in physics experiments can be done easily and fun.

Fast estimation of chlorophyll content on plant leaves using the light sensor of a smartphone

Medir clorofila puede apoyar decisiones de fertilización nitrogenada de plantas. Usando un dispositivo impreso en 3D y un LED rojo, aquí probamos la factibilidad de usar un teléfono celular para estimar clorofila por transmisión de luz. Al comparar 30 lecturas de trasmisión de luz roja (663 nm) por hojas de sorgo Sorghum bicolor (L.) Moench, obtenidas del teléfono y de un espectrómetro estándar, se encontró un buen coeficiente de determinación (r2 = 0.9067). Adicionalmente, se hizo una comparación entre las lecturas del teléfono y un SPAD 502TM (un dispositivo comercial para la estimación del contenido de clorofila) en hojas de crisantemo Dendranthema grandiflora Tzvelev, obteniendo una buena correlación entre ambas medidas. La transmisión medida en hojas de S. bicolor de plantas de invernadero fertilizadas con nitrógeno también presentó buen ajuste con la altura de las plantas, sugiriendo la posibilidad de estimar fácilmente el contenido de clorofila en hojas usando teléfonos inteligentes.

Oscillations studied with the smartphone ambient light sensor

This paper makes use of a smartphone's ambient light sensor to analyse a system of two coupled springs undergoing either simple or damped oscillatory motion. The period, frequency and stiffness of the spring, together with the damping constant and extinction time, are extracted from light intensity curves obtained using a free Android application. The results demonstrate the instructional value of mobile phone sensors as a tool in the physics laboratory.