Novel versatile smart phone based Microplate readers for on-site diagnoses

Rapid and Online Microvolume Flow-Through Dialysis Probe for Sample Preparation in Veterinary Drug Residue Analysis

A rapid and online microvolume flow-through dialysis probe designed for sample preparation in the analysis of veterinary drug residues is introduced. This study addresses the need for efficient and green sample preparation methods that reduce chemical waste and reagent use. The dialysis probe integrates with liquid chromatography and mass spectrometry (LC-MS) systems, facilitating automated, high-throughput analysis. The dialysis method utilizes minimal reagent volumes per sample, significantly reducing the generation of solvent waste compared to traditional sample preparation techniques. Several veterinary drugs were spiked into tissue homogenates and analyzed to validate the probe's efficacy. A diagnostic sensitivity of >97% and specificity of >95% were obtained for this performance evaluation. The results demonstrated the effective removal of cellular debris and particulates, ensuring sample integrity and preventing instrument clogging. The automated dialysis probe yielded recovery rates between 27 and 77% for multiple analytes, confirming its potential to streamline veterinary drug residue analysis, while adhering to green chemistry principles. The approach highlights substantial improvements in both environmental impact and operational efficiency, presenting a viable alternative to conventional sample preparation methods in regulatory and research applications.

High-sensitivity flip chip blue Mini-LEDs miniaturized optical instrument for non-invasive glucose detection

The colorimetric detection of glucose typically involves a peroxidase reaction producing a color, which is then recorded and analyzed. However, enzyme detection has difficulties with purification and storage. In addition, replacing enzyme detection with chemical methods involves time-consuming steps such as centrifugation and purification and the optical instruments used for colorimetric detection are often bulky and not portable. In this study, ammonium metavanadate and sulfuric acid were used to prepare the detection solution instead of peroxidase to produce color. We also analyzed the effect of different concentrations of detection solution on absorbance sensitivity. Finally, a flip chip blue Mini-LEDs miniaturized optical instrument (FC blue Mini-LEDs MOI) was designed for glucose detection using optics fiber, collimating lenses, a miniaturized spectrometer, and an FC Blue Mini-LEDs with a center wavelength of 459 nm. While detecting glucose solutions in the concentration range of 0.1-10 mM by the developed MOI, the regression equation of y = 0.0941x + 0.1341, R2 of 0.9744, the limit of detection was 2.15 mM, and the limit of quantification was 7.163 mM. Furthermore, the preparation of the detection solution only takes 10 min, and the absorbance sensitivity of the optimized detection solution could be increased by 2.3 times. The detection solution remained stable with only a 0.6% decrease in absorbance compared to the original after storing it in a refrigerated environment at 3 °C for 14 days. The method proposed in this study for detecting glucose using FC blue light Mini-LEDs MOI reduces the use of peroxidase. In addition, it has a wide detection range that includes blood as well as non-invasive saliva and tear fluids, providing patients with a miniaturized, highly sensitive, and quantifiable glucose detection system.

Portable Colorimetric Device with Commercial Microplates for Quantitative Detection of Urine Biomarkers: Design, Development, and Clinical Evaluation

Urine biomarkers are important in monitoring diseases related to human kidney function. The current processes for measuring biomarker levels in urine samples require patients to regularly visit clinical facilities, which is inconvenient and sometimes impossible for patients in rural areas. Therefore, portable analysis devices for the measurement of urine biomarkers are urgently requested. In this study, a portable platform using colorimetry, a common and simple-to-operate chemical analysis technique, was developed to measure urine biomarkers. The device, using commercial test kits as recognising reagents and a 96-well microplate as a solution container, provides quantitative measures of biomarker concentration. Moreover, the proposed device introduces a calibration method to minimise the dependence of regular maintenance. The device’s performance was evaluated with urine from 73 renal patients and its results matched with clinical results well. The device has the potential for measuring urine creatinine, in addition to performing a variety of commercial assays for biomarker detection in human body fluids in general.

Low-Cost Microplate Reader with 3D Printed Parts for under 500 USD

A 96-well microplate reader for absorption spectroscopy was designed, constructed, and tested at a total cost of ca. 500 USD. The reduced cost of the device represents the major technical contribution of this manuscript, as costs were reduced 7 fold from previous reports. The device was able to achieve 3σ limits of detection of ca. 0.01 absorbance units (AU) over a 60 second measurement for the mid-visible wavelength range. Component parts are either commercially available, or 3D printed from plans. Analysis wavelength can be altered throughout the visible region through use of various photographic or theatrical filters. This feature allows the well plate reader to be used for typical laboratory assays such as cell population estimation by optical density (OD) at 600 nm, or enzyme-linked immunosorbent assays (ELISA) at 450 nm. This manuscript reports on the motivation and process of constructing the device, lists required parts, presents data demonstrating device function, and provides the community of scholars with plans to reproduce the work. The device can be reproduced in laboratories lacking sufficient resources to purchase commercially available options and this outcome contributes towards empowerment of individuals and equity of scientific enquiry.

A nanoenzyme linked immunochromatographic sensor for rapid and quantitative detection of SARS-CoV-2 nucleocapsid protein in human blood

The establishment of a simple, low-cost, high-sensitive and rapid immunoassay for detecting SARS-CoV-2 antigen in human blood is an effective mean of discovering early SARS-CoV-2 infection and controlling the pandemic of COVID-19. Herein, a smartphone based nanozyme linked immunochromatographic sensor (NLICS) for the detection of SARS-CoV-2 nucleocapsid protein (NP) has been developed on demand. The system is integrated by disposable immunochromatography assay (ICA) and optical sensor devices. Immunoreaction and enzyme-catalyzed substrate color reaction were carried out on the chromatographic strip in a device, of which the light signal was read by a photometer through a biosensor channel, and the data was synchronously transmitted via the Bluetooth to the app in-stored smartphone for reporting the result. With a limit of detection (LOD) of 0.026 ng/mL NP, NLICS had the linear detection range (LDR) between 0.05 and 1.6 ng/mL NP, which was more sensitive than conventional ICA. NLICS took 25 min for reporting results. For detection of NP antigen in clinical serum samples from 21 COVID-19 patients and 80 healthy blood donor controls, NLICS and commercial enzyme linked immunosorbent assay (ELISA) had 76.2% or 47.6% positivity, and 100% specificity, respectively (P = 0.057), while a good correlation coefficient (r = 0.99) for quantification of NP between two assays was obtained. In conclusion, the NLICS was a rapid, simple, cheap, sensitive and specific immunochromatographic sensing assay for early diagnosis of SARS-CoV-2 infection.

A SARS-CoV-2 nucleocapsid ELISA represents a low-cost alternative to lateral flow testing for community screening in LMI countries

Background Controlling the spread of SARS-CoV-2 is problematic because of transmission driven by asymptomatic and pre-symptomatic individuals. Community screening can help identify these individuals but is often too expensive for countries with limited health care resources. Low-cost ELISA assays may address this problem, but their use has not yet been widely reported.

Methods We developed a SARS-CoV-2 nucleocapsid ELISA and assessed its diagnostic performance on nose and throat swab samples from UK hospitalised patients and sputum samples from patients in Ghana.

Results The ELISA had a limit of detection of 8.4 pg/ml antigen and 16 pfu/ml virus. When tested on UK samples (128 positive and 10 negative patients), sensitivity was 58.6% (49.6–67.2) rising to 78.3% (66.7–87.3) if real-time PCR Ct values > 30 were excluded, while specificity was 100% (69.2–100). In a second trial using the Ghanaian samples (121 positive, 96 negative), sensitivity was 52% (42.8–61.2) rising to 72.6% (61.8–81.2) when a > 30 Ct cut-off was applied, while specificity was 100% (96.2–100).

Conclusions: Our data show that nucleocapsid ELISAs can test a variety of patient sample types while achieving levels of sensitivity and specificity required for effective community screening. Further investigations into the opportunities that this provides are warranted.

A self-designed versatile and portable sensing device based on smart phone for colorimetric detection

A UV-vis spectrometer, as a sort of important analytical instrument, has been widely used to analyze various substances. However, expensive equipment and skilled operators are required, which limits its broad applications for out-of-lab and daily measurements. In this work, a self-designed sensing device based on smart phone was developed as a sensitive, cost-effective, facile, and portable testing tool. The sensing device fabricated by 3D printing was used to lodge a sample solution and produce a light signal, and the optical sensor on a smart phone worked as a transducer. The light source in the device generated wide-wavelength radiation, which passed through an inner filter and only light of a designated wavelength reached the testing solution. The intensity of transmitted light was then measured by an optical sensor internally installed in most smart phones, where the signals were processed as well. The feasibility of our device was verified by detecting four kinds of common heavy metal ions in actual water samples, and the testing results showed good agreement with those obtained from the UV-vis spectrometer. This work is expected to shed some light on the construction of smart phone-based sensors, featuring decent portability, simple operation, low cost, high sensitivity, and good accuracy.

A Smartphone-Based Sensing System for On-Site Quantitation of Multiple Heavy Metal Ions Using Fluorescent Carbon Nanodots-Based Microarrays

The development of cost-effective and versatile sensing system for simultaneous and rapid quantitation of multiple targets is highly demanded for environmental surveillance, food safety inspection, home healthcare, etc. This work reports on (1) paper-based microarrays relying on fluorescence turn-off of carbon nanodots (CDs) for analyte recognition and (2) a stand-alone smartphone-based portable reader (SBR) installed with a custom-designed APP (SBR-App), which can accurately and reproducibly acquire fluorescence change from the microarray chip, automatically report the results, generate and share the reports via wireless network. Simultaneous detection of Hg²⁺, Pb²⁺, and Cu²⁺ in the Pearl River water samples was achieved with the reported sensing system. End-user operation is limited to pipet samples to the microarray chip, insert the chip to the SBR, and open the SBR-App to acquire an image 5 min after sample introduction. There is no requirement for complicated sample pre-treatment and expensive equipment except for a smartphone. This versatile and cost-effective smartphone-based sensing system featured with reliability and simplicity is ideally suited for user- and eco-friendly point-of-need detection in resource-constrained environments.

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.

Smartphone technology and its applications in urology: a review of the literature

PURPOSE

Smartphone technology has propelled the evolution of health-related mobile technology, referred to as mobile health (mHealth). With the rise of smartphone ownership and the growing popularity of health-related smartphone usage, mHealth offers potential benefits for both patients and health care providers. The objective of this review is to assess the current state of smartphone technology in urology.

METHODS

A literature search of PubMed database was conducted to identify articles reporting on smartphone technology in urology. Publications were included if they focused on smartphone mHealth technology pertinent to the field of urology or included an evaluation of urological applications in digital stores.

RESULTS

We identified 50 publications focused on the use of smartphones in urology. Studies were then grouped into the following categories: smartphones employing the built-in camera and light source, applications specific to prostate cancer, urolithiasis, pediatric urology, and as educational tools for urologists. In 23/50 (46%) studies, smartphone technology/intervention was compared to a control group or to standard of care. In this regard, smartphone technology did not demonstrate benefit over standard of care in 13 studies. In contrast, in 10 studies, smartphone interventions were proven beneficial over current practice.

CONCLUSIONS

Smartphone technology is constantly evolving and has the potential to improve urological care and education. Of concern to consumer and urologist alike is that these downloadable programs are limited due to the accuracy of their content, risk of confidentiality breach, and the lack of central regulation and professional involvement in their development.

Plasmonic ELISA for Sensitive Detection of Disease Biomarkers with a Smart Phone-Based Reader

Serum myoglobin is one of the earliest markers for the diagnosis of acute myocardial infarction. It is, therefore, critical to develop a point-of-care testing technology for myoglobin detection. In this work, we reported a sensitive plasmonic immunoassay-based on enzyme-mediated localized surface plasmon resonance change of gold nanorods for the point-of-care testing detection of myoglobin. In addition, we developed a novel plasmonic immunoassay reader using the ambient light sensor of smart phone to increase the accessibility and utility of the plasmonic immunoassay. The linear detection range of gold nanorods-based plasmonic immunoassay for myoglobin detection was 0.1-1000 ng mL-1 and the limit of detection was 0.057 ng mL-1. Myoglobin in serum samples was also analyzed by the plasmonic immunoassay. The results were significantly correlated with those of conventional enzyme-linked immunosorbent assay. The plasmonic immunoassay, coupled with smart phone-based reader, could be widely used for point-of-care testing application of acute myocardial infarction, especially in the regions with limited technological resources.

Consumer-friendly food allergen detection: moving towards smartphone-based immunoassays

In this critical review, we provide a comprehensive overview of immunochemical food allergen assays and detectors in the context of their user-friendliness, through their connection to smartphones. Smartphone-based analysis is centered around citizen science, putting analysis into the hands of the consumer. Food allergies represent a significant worldwide health concern and consumers should be able to analyze their foods, whenever and wherever they are, for allergen presence. Owing to the need for a scientific background, traditional laboratory-based detection methods are generally unsuitable for the consumer. Therefore, it is important to develop simple, safe, and rapid assays that can be linked with smartphones as detectors to improve user accessibility. Smartphones make excellent detection systems because of their cameras, embedded flash functions, portability, connectivity, and affordability. Therefore, this review has summarized traditional laboratory-based methods for food allergen detection such as enzyme-linked-immunosorbent assay, flow cytometry, and surface plasmon resonance, and the potential to modernize these methods by interfacing them with a smartphone readout system, based on the aforementioned smartphone characteristics. This is the first review focusing on smartphone-based food-allergen detection methods designed with the intention of being consumer-friendly. Graphical abstract A smartphone-based food allergen detection system in three easy steps (1) sample preparation, (2) allergen detection on a smartphone using antibodies, which then transmits the data wirelessly, (3) analytical results sent straight to smartphone.

A simple and compact smartphone-based device for the quantitative readout of colloidal gold lateral flow immunoassay strips

Colloidal gold lateral flow immunoassay strips (AuNPs-LFIS) have been widely applied as qualitative diagnostic tools for point-of-care tests (POCT). If strip readers were incorporated, their use could be extended to quantitative analysis. However, their cost and non-portability render commercial strip readers unavailable for use in either home testing, community or rural hospital diagnosis. This is particularly true for on-site testing. Here, a smartphone-based reader was designed and 3D-printed for quantitatively assess AuNPs-LFIS. The basic principle of the devise was relying on a smartphone's ambient light sensor (SPALS). This sensor was harnessed to measure the transmitted light intensities originating from the T-lines on the strips, the transmitted light intensities vary with concentration of AuNP on the T-lines. To validate this approach, our newly developed smartphone's ambient light sensor-based reader (SPALS-reader) was used to readout AuNPs-LFIS of three analytical targets: cadmium ion (Cd²⁺; limit of detection (LOD) was 0.16 ng/mL), clenbuterol (CL; LOD was 0.046 ng/mL), and porcine epidemic diarrhea virus (PEDV; LOD was 0.055 μg/mL). The result showed good consistency with the results of conventional image analysis approaches, indicating that the smartphone-based device is appropriate for use in AuNPs-LFIS readouts. Compared with the traditional analysis method, the developed AuNPs-LFIS reader is easier operated, lower cost and more portable, which provided an on-site quantitative analysis tool for AuNPs-LFIS and enhances the applied range of AuNPs-LFIS.

A Rapid Method for Antigen-Specific Hybridoma Clone Isolation

Using an enzyme-linked immunosorbent assay (ELISA) and limited dilution methods to screen and clone antigen-specific hybridoma cells is extremely time-consuming and labor-intensive. This work features a simple and rapid cell surface fluorescence immunosorbent assay (CSFIA), designed for the detection and isolation of antigen-specific hybridoma clones. In this assay, antigens are first anchored to the hybridoma cell surface through a dual-functioning molecular Oleyl-PEG4000-NHS. Specific antibodies secreted from hybridoma cells are then captured by the antigens on the cell surface. Positive hybridoma cells are stained using a fluorescently labeled anti-mouse IgG-Fc antibody. After the addition of a methylcellulose semisolid medium, positive clones are easily picked using a pipet. These positive cell clones can be used to produce monoclonal antibodies after direct expansion. Using this method, positive hybridoma clones against both malachite green and porcine epidemic diarrhea virus are selected with high efficiency. Compared to the ELISA-based method, the CSFIA-based method achieved the capability of isolating >2-fold more hybridoma clones in <25% of the corresponding processing time. In brief, the CSFIA-based method is highly efficient and inexpensive with a simple and direct operation, which is an excellent candidate method for antigen-specific positive clone isolation in a monoclonal antibody preparation.

A Portable Smart-Phone Readout Device for the Detection of Mercury Contamination Based on an Aptamer-Assay Nanosensor

The detection of environmental mercury (Hg) contamination requires complex and expensive instruments and professional technicians. We present a simple, sensitive, and portable Hg²⁺ detection system based on a smartphone and colorimetric aptamer nanosensor. A smartphone equipped with a light meter app was used to detect, record, and process signals from a smartphone-based microwell reader (MR S-phone), which is composed of a simple light source and a miniaturized assay platform. The colorimetric readout of the aptamer nanosensor is based on a specific interaction between the selected aptamer and Hg²⁺, which leads to a color change in the reaction solution due to an aggregation of gold nanoparticles (AuNPs). The MR S-phone-based AuNPs-aptamer colorimetric sensor system could reliably detect Hg²⁺ in both tap water and Pearl River water samples and produced a linear colorimetric readout of Hg²⁺ concentration in the range of 1 ng/mL-32 ng/mL with a correlation of 0.991, and a limit of detection (LOD) of 0.28 ng/mL for Hg²⁺. The detection could be quickly completed in only 20 min. Our novel mercury detection assay is simple, rapid, and sensitive, and it provides new strategies for the on-site detection of mercury contamination in any environment.