Mobile Phone Imaging Research Articles

Dual-mode electrochemiluminescence sensing and phone imaging assays based on bipolar electrode for kanamycin detection

Excessive use of antibiotics will enter the water environment and soil through the biological chain, and then transfer to the human body through food, resulting in drug resistance, kidney toxicity and other health problems, so it is urgent to develop highly sensitive detection methods of antibiotics. Here, we designed a dual-mode sensor platform based on closed bipolar electrode (cBPE) electroluminescence (ECL) and mobile phone imaging to detect kanamycin in seawater. The prepared CN-NV-550 displayed extremely intense ECL signal, allowing for convenient mobile phone imaging. The cBPE was combined with DNA cycle amplification technology to prevent the mutual interference between target and the luminescent material, and realized the amplification of signal. In the presence of target Kana, Co3O4 was introduced to the cBPE anode by DNA cycle amplification product, and accelerated the oxidation rate of uric acid (UA). Thus, the electroluminescence response of CN-NV-550 on cBPE cathode was much improved due to the charge balance of the cBPE, achieving both ECL detection and mobile phone imaging assay of Kana, which much improved the accuracy and efficiency of assay. The limit of detection (LOD) in this work is 0.23 pM, and LOD for mobile phone imaging is 0.39 pM. This study integrate ECL imaging visualization of CN-NV-550 and high electrocatalytic activity of Co3O4 into cBPE-ECL detection, providing a new perspective for antibiotic analysis, and has great potential for practical applications, especially in Marine environmental pollution monitoring.

Spatial-Potential-Color-Resolved Bipolar Electrode Electrochemiluminescence Biosensor Using a CuMoOx Electrocatalyst for the Simultaneous Detection and Imaging of Tetracycline and Lincomycin.

A spatial-potential-color-resolved bipolar electrode electrochemiluminescence biosensor (BPE-ECL) using a CuMoOx electrocatalyst was constructed for the simultaneous detection and imaging of tetracycline (TET) and lincomycin (LIN). HOF-101 emitted peacock blue light under positive potential scanning, and CdSe quantum dots (QDs) emitted green light under negative potential scanning. CuMoOx could catalyze the electrochemical reduction of H2O2 to greatly increase the Faradic current of BPE and realize the ECL signal amplification. In channel 1, CuMoOx-Aptamer II (TET) probes were introduced into the BPE hole (left groove A) by the dual aptamer sandwich method of TET. During positive potential scanning, the polarity of BPE (left groove A) was negative, resulting in the electrochemical reduction of H2O2 catalyzed by CuMoOx, and the ECL signal of HOF-101 was enhanced for detecting TET. In channel 2, CuMoOx-Aptamer (LIN) probes were adsorbed on the MXene of the driving electrode (DVE) hole (left groove B) by hydrogen-bonding and metal-chelating interactions. LIN bound with its aptamers, causing CuMoOx to fall off. During negative potential scanning, the polarity of DVE (left groove B) was negative and the Faradic current decreased. The ECL signal of CdSe QDs was reduced for detecting LIN. Furthermore, a portable mobile phone imaging platform was built for the colorimetric (CL) detection of TET and LIN. Thus, the multiple mode-resolved detection of TET and LIN could be realized simultaneously with only one potential scan, which greatly improved detection accuracy and efficiency. This study opened a new technology of BPE-ECL sensor application and is expected to shine in microchips and point-of-care testing (POCT).

Engineering the Ultrasensitive Visual Whole-Cell Biosensors by Evolved MerR and 5' UTR for Detection of Ultratrace Mercury.

The existing mercury whole-cell biosensors (WCBs, parts per billion range) are not able to meet the real-world requirements due to their lack of sensitivity for the detection of ultratrace mercury in the environment. Ultratrace mercury is a potential threat to human health via the food chain. Here, we developed an ultrasensitive mercury WCB by directed evolution of the mercury-responsive transcriptional activator (MerR) sensing module to detect ultratrace mercury. Subsequently, the mutant WCB (m4-1) responding to mercury in the parts per trillion range after 1 h of induction was obtained. Its detection limit (LOD) was 0.313 ng/L, comparable to those of some analytical instruments. Surprisingly, the m4-1 WCB also responded to methylmercury (LOD = 98 ng/L), which is far more toxic than inorganic mercury. For more convenient detection, we have increased another green fluorescent protein reporter module with an optimized 5' untranslated region (5' UTR) sequence. This yields two visual WCBs with an enhanced fluorescence output. At a concentration of 2.5 ng/L, the fluorescence signals can be directly observed by the naked eye. With the combination of mobile phone imaging and image processing software, the 2GC WCB provided simple, rapid, and reliable quantitative and qualitative analysis of real samples (LOD = 0.307 ng/L). Taken together, these results indicate that the ultrasensitive visual whole-cell biosensors for ultratrace mercury detection are successfully designed using a combination of directed evolution and synthetic biotechnology.

Mobile Phone Imaging Point Cloud Modelling for 3D Recording and Measurement of Small Scenes of Suspected Fossil Outcrops Found in the Field

Mobile Phone Imaging Point Cloud Modelling for 3D Recording and Measurement of Small Scenes of Suspected Fossil Outcrops Found in the Field

Deep reinforcement learning-designed radiofrequency waveform in MRI

Carefully engineered radiofrequency (RF) pulses play a key role in a number of systems such as mobile phone, radar, and magnetic resonance imaging. The design of an RF waveform, however, is often posed as an inverse problem with no general solution. As a result, various design methods each with a specific purpose have been developed based on the intuition of human experts. In this work, we propose an artificial intelligence (AI)-powered RF pulse design framework, DeepRF, which utilizes the self-learning characteristics of deep reinforcement learning to generate a novel RF pulse. The effectiveness of DeepRF is demonstrated using four types of RF pulses that are commonly used. The DeepRF-designed pulses successfully satisfy the design criteria while reporting reduced energy. Analyses demonstrate the pulses utilize new mechanisms of magnetization manipulation, suggesting the potentials of DeepRF in discovering unseen design dimensions beyond human intuition. This work may lay the foundation for an emerging field of AI-driven RF waveform design.

A randomized controlled trial of an mHealth intervention for increasing access to HIV testing and care among young cisgender men and transgender women: the mLab App study protocol

BackgroundThe number of youth living with HIV in the United States (US) continues to rise, and racial, ethnic, and sexual minority youth including young men who have sex with men (YMSM) and young transgender women (YTGW) bear a disproportionate burden of the HIV epidemic. Due to social and healthcare system factors, many YMSM and YTGW do not seek HIV testing services and are therefore less likely to be aware that they are infected. Mobile health technology (mHealth) has the ability to increase uptake of HIV testing among these populations. Thus, the mLab App—which combines HIV prevention information with a mobile phone imaging feature for interpreting at-home HIV test results—was developed to improve testing rates and linkage to care among Black, Latino, and other YMSM and YTGW living in New York City and Chicago and their surrounding areas.MethodsThis study is a three-arm randomized controlled trial among YMSM and YTGW aged 18–29 years. Participants are randomized to either the mLab App intervention including HIV home test kits and standard of preventive care, standard of preventive care only, or HIV home test kits and standard of preventive care only.DiscussionmHealth technology used for HIV prevention is capable of delivering interventions in real-time, which creates an opportunity to remotely reach users across the country to strengthen their HIV care continuum engagement and treatment outcomes. Specifically during the COVID-19 pandemic, mHealth technology combined with at-home testing may prove to be essential in increasing HIV testing rates, especially among populations at high-risk or without regular access to HIV testing.Trial registrationThis trial was registered with Clinicaltrials.gov (NCT03803683) on January 14, 2019.

SARS-CoV-2 RNA Detection by a Cellphone-Based Amplification-Free System with CRISPR/CAS-Dependent Enzymatic (CASCADE) Assay.

CRISPR (Clustered regularly interspaced short palindromic repeats)‐based diagnostic technologies have emerged as a promising alternative to accelerate delivery of SARS‐CoV‐2 molecular detection at the point of need. However, efficient translation of CRISPR‐diagnostic technologies to field application is still hampered by dependence on target amplification and by reliance on fluorescence‐based results readout. Herein, an amplification‐free CRISPR/Cas12a‐based diagnostic technology for SARS‐CoV‐2 RNA detection is presented using a smartphone camera for results readout. This method, termed Cellphone‐based amplification‐free system with CRISPR/CAS‐dependent enzymatic (CASCADE) assay, relies on mobile phone imaging of a catalase‐generated gas bubble signal within a microfluidic channel and does not require any external hardware optical attachments. Upon specific detection of a SARS‐CoV‐2 reverse‐transcribed DNA/RNA heteroduplex target (orf1ab) by the ribonucleoprotein complex, the transcleavage collateral activity of the Cas12a protein on a Catalase:ssDNA probe triggers the bubble signal on the system. High analytical sensitivity in signal detection without previous target amplification (down to 50 copies µL−1) is observed in spiked samples, in ≈71 min from sample input to results readout. With the aid of a smartphone vision tool, high accuracy (AUC = 1.0; CI: 0.715 – 1.00) is achieved when the CASCADE system is tested with nasopharyngeal swab samples of PCR‐positive COVID‐19 patients.

Comment to: Thermal imaging for microvascular free tissue transfer monitoring: Feasibility study using a low cost, commercially available mobile phone imaging system

Comment to: Thermal imaging for microvascular free tissue transfer monitoring: Feasibility study using a low cost, commercially available mobile phone imaging system

Two-Fluorophore Mobile Phone Imaging of Biplexed Real-Time NAATs Overcomes Optical Artifacts in Highly Scattering Porous Media.

Nucleic acid amplification tests (NAATs) are common in laboratory and clinical settings because of their low time to result and exquisite sensitivity and specificity. Laboratory NAATs include onboard positive controls to reduce false negatives and specialized hardware to enable real-time fluorescence detection. Recent efforts to translate NAATs into at-home tests sacrifice one or more of the benefits of laboratory NAATs, such as sensitivity, internal amplification controls (IACs), or time to result. In this manuscript, we describe a mobile-phone-based strategy for real-time imaging of biplexed NAATs in paper. The strategy consisted of: (1) using mobile phones with multipass excitation and emission filters on the flash and camera to image the signal from distinct fluorophore-labeled probe types in a biplexed NAAT in a glass fiber membrane; and (2) analyzing the differential fluorescence signal between the red and green color channels of phone images to overcome a strong evaporation-induced optical artifact in heated glass fiber pads due to changes in the refractive index. We demonstrated that differential fluorescence imaging enabled low limits of detection (316 copies of methicillin-resistant Staphylococcus aureus DNA) in our lab's "MD NAAT" platform, even in biplexed isothermal strand displacement amplification reactions containing 100k copies of coamplifying IAC DNA templates. These results suggest that two-fluorophore mobile phone imaging may enable translating the benefits of extant laboratory-based, real-time NAATs to the point of care.

Thermal imaging for microvascular free tissue transfer monitoring: Feasibility study using a low cost, commercially available mobile phone imaging system.

The use of infrared thermography to evaluate the perfusion of tissue flaps have been studied. This study aims to evaluate the utility of thermal imaging for flap monitoring with a low-cost, readily available smartphone imaging device. Adult subjects who underwent head and neck reconstruction using a microvascular free flap with a cutaneous paddle were recruited. Thermal images were taken of the free flap before, during and after anastomosis. Thermal images were analyzed by measuring the average flap temperature minus the average surrounding tissue temperature (dT). Twenty-one patients were enrolled. The mean dT for flaps intraoperatively prior to anastomosis was -11.47 °F. For 20 patients, dT averaged between -0.30 to 0.12 °F. One flap was inadequately perfused and dT was found to be -4.35 °F. Low cost, mobile smartphone devices such as the thermal camera may provide an objective method of monitoring microvascular free flaps. 2 Prospective Cohort Study.

Mobile platform for rapid sub–picogram-per-milliliter, multiplexed, digital droplet detection of proteins

Digital droplet assays-in which biological samples are compartmentalized into millions of femtoliter-volume droplets and interrogated individually-have generated enormous enthusiasm for their ability to detect biomarkers with single-molecule sensitivity. These assays have untapped potential for point-of-care diagnostics but are currently mainly confined to laboratory settings, due to the instrumentation necessary to serially generate, control, and measure tens of millions of droplets/compartments. To address this challenge, we developed an optofluidic platform that miniaturizes digital assays into a mobile format by parallelizing their operation. This technology is based on three key innovations: (i) the integration and parallel operation of a hundred droplet generators onto a single chip that operates >100× faster than a single droplet generator, (ii) the fluorescence detection of droplets at >100× faster than conventional in-flow detection using time domain-encoded mobile phone imaging, and (iii) the integration of on-chip delay lines and sample processing to allow serum-to-answer device operation. To demonstrate the power of this approach, we performed a duplex digital ELISA. We characterized the performance of this assay by first using spiked recombinant proteins in a complex media (FBS) and measured a limit of detection, 0.004 pg/mL (300 aM), a 1,000× improvement over standard ELISA and matching that of the existing laboratory-based gold standard digital ELISA system. We additionally measured endogenous GM-CSF and IL6 in human serum from n = 14 human subjects using our mobile duplex assay, and showed excellent agreement with the gold standard system ([Formula: see text]).

Telesurveillance: Exploring the Use of Mobile Phone Imaging in the Follow-Up of Orthopedic Patients with Hand Trauma.

Background:Intra-articular phalangeal fractures involving the proximal interphalangeal joint (PIPJ) are notoriously difficult injuries to treat and often require regular follow-up to assess progress, guide treatment, and determine outcomes. Some patients often have to travel long distances for follow-up care. The aim of our study was to assess the clinical outcomes of intra-articular fractures of the PIPJ through use of clinical pictures sent through a mobile phone.Methods:A retrospective study was conducted of a consecutive group of patients treated with a static external fixator (Micro Hoffman-2 Stryker®) between 2006 and 2016 for an intra-articular fracture of the PIPJ. Range of motion (ROM) at the PIPJ was assessed through clinical pictures taken on a mobile phone.Results:Clinical images were received from 15 patients with a mean age of 31.9 years (range 15-51), of which 73.3% of patients were male. Mean length of follow-up was 39 months. Around 73.3% of injuries occurred while playing a sport. Mean PIPJ ROM assessed through the clinical images was 67°.Conclusion:Our study shows that it was possible to assess ROM at the PIPJ through the use of clinical pictures taken by mobile phone. The use of mobile phones to take images provided a simple, easy, and convenient means of assessing outcome in this cohort of patients. We describe a method of follow-up that may have a greater role in the future.

Mobile Phone Ratiometric Imaging Enables Highly Sensitive Fluorescence Lateral Flow Immunoassays without External Optical Filters.

Paper-based diagnostic tests based on the lateral flow immunoassay concept promise low-cost, point-of-care detection of infectious diseases, but such assays suffer from poor limits of detection. One factor that contributes to poor analytical performance is a reliance on low-contrast chromophoric optical labels such as gold nanoparticles. Previous attempts to improve the sensitivity of paper-based diagnostics include replacing chromophoric labels with enzymes, fluorophores, or phosphors at the expense of increased fluidic complexity or the need for device readers with costly optoelectronics. Several groups, including our own, have proposed mobile phones as suitable point-of-care readers due to their low cost, ease of use, and ubiquity. However, extant mobile phone fluorescence readers require costly optical filters and were typically validated with only one camera sensor module, which is inappropriate for potential point-of-care use. In response, we propose to couple low-cost ultraviolet light-emitting diodes with long Stokes-shift quantum dots to enable ratiometric mobile phone fluorescence measurements without optical filters. Ratiometric imaging with unmodified smartphone cameras improves the contrast and attenuates the impact of excitation intensity variability by 15×. Practical application was shown with a lateral flow immunoassay for influenza A with nucleoproteins spiked into simulated nasal matrix. Limits of detection of 1.5 and 2.6 fmol were attained on two mobile phones, which are comparable to a gel imager (1.9 fmol), 10× better than imaging gold nanoparticles on a scanner (18 fmol), and >2 orders of magnitude better than gold nanoparticle-labeled assays imaged with mobile phones. Use of the proposed filter-free mobile phone imaging scheme is a first step toward enabling a new generation of highly sensitive, point-of-care fluorescence assays.

Research on Positioning Technology Based on the Mobile Phone Imaging Equipment

The complexity of indoor environment has become the bottleneck of the relying on satellite navigation and mobile network positioning technology. With the development of the city, the demand of indoor positioning service is increasing day by day. In this paper, based on the principle of mobile phone image localization, indoor precision positioning is studied. For the adaptive problem of imaging positioning technology, genetic algorithm is used to realize the intelligent calculation of positioning algorithm. The image points identified by the image are involved in the iterative process as constraints and the error correction Ability to reduce the computational complexity of the target solution to achieve fast and accurate positioning.

Mobile phone imaging and cloud-based analysis for standardized malaria detection and reporting.

Rapid diagnostic tests (RDTs) have been widely deployed in low-resource settings. These tests are typically read by visual inspection, and accurate record keeping and data aggregation remains a substantial challenge. A successful malaria elimination campaign will require new strategies that maximize the sensitivity of RDTs, reduce user error, and integrate results reporting tools. In this report, an unmodified mobile phone was used to photograph RDTs, which were subsequently uploaded into a globally accessible database, REDCap, and then analyzed three ways: with an automated image processing program, visual inspection, and a commercial lateral flow reader. The mobile phone image processing detected 20.6 malaria parasites/microliter of blood, compared to the commercial lateral flow reader which detected 64.4 parasites/microliter. Experienced observers visually identified positive malaria cases at 12.5 parasites/microliter, but encountered reporting errors and false negatives. Visual interpretation by inexperienced users resulted in only an 80.2% true negative rate, with substantial disagreement in the lower parasitemia range. We have demonstrated that combining a globally accessible database, such as REDCap, with mobile phone based imaging of RDTs provides objective, secure, automated, data collection and result reporting. This simple combination of existing technologies would appear to be an attractive tool for malaria elimination campaigns.

Optimization for optical characteristics of WFC mask of mobile phone imaging system

Optimization for optical characteristics of WFC mask of mobile phone imaging system

Pilot testing automatic mobile phone imaging coupled with 24 hour recalls: Image Diet Day

Dietary recalls are subject to intrusions and omissions of foods due to imperfect memory. To remedy this we coupled automated imaging with a computer assisted 24‐hour recall for feasibility in 14 subjects. Mobile phones worn around the neck were programmed to autonomously capture and transmit images every 10 seconds. A website presented these the following day to subjects conducting a web based 24‐hour recall. Logistic issues included IRB concerns, proper phone positioning, adequate energy reserves to continually transmit images and development of user‐friendly software to present a manageable number of images. Phone usage was monitored through transmitted images. Subjective responses to their experience with the camera showed 79% of participants having no technical problems. 93% found the images to be helpful. Across these users there were 110 distinct eating episodes and 11,090 images uploaded. There was an average of 101 images per episode, ranging from a max of 775 to a minimum of 1; reflecting the diversity of short snacks and longer meals across study participants. Image processing filters developed to prune out under‐exposed, over‐exposed, and blurry images introduced only seconds of processing overhead. Participants provided invaluable feedback on their experiences with the phones, how to improve the camera phones, how to support their wear and concerns about their operation.

Fast video demosaicking solution for mobile phone imaging applications

This paper introduces a cost-effective video demosaicking solution suitable for mobile phones with video capturing capabilities. The proposed solution is a spatio-temporal demosaicking scheme, which operates over three subsequent frames of the acquired video sequence. To rapidly demosaick the raw, color filter array (CFA), spatiotemporal video data our solution uses multi-stage processing concepts and builds on the principles of refined spectral modeling and self-adaptation to varying spatiotemporal characteristics. The proposed solution accommodates cost-effective considerations inherent in mobile phone imaging and produces a visually pleasing demosaicked video sequence.