A novel combination of quick response code and microfluidic paper-based analytical devices for rapid and quantitative detection

A QR code-integrated chromogenic paper strip for detection of hydrogen peroxide in aqueous samples

Hydrogen peroxide (H2O2) is commonly used as a preservative, disinfectant, bleach, and oxidizing agent. The prolonged consumption of H2O2 adulterated milk is harmful to human health when consumed in the diet. Exposure to H2O2 can lead to oxidative stress, cell damage and tissue injury. Due to the potential adverse effects, the use of hydrogen peroxide is regulated in certain applications, such as in food, water treatment plants and medical products. Several methods are available for the detection of H2O2 in various matrices. Here, a method and QR code-integrated chromogenic paper strip for the detection of H2O2 in aqueous samples has been developed. The spectrophotometric method showed an LOD and LOQ of 0.00087 ± 8.70 ×10-5% (v/v) and 0.0037 ± 0.0003% (v/v), respectively. The paper-based chromogenic strip prepared by immobilizing recognition solution onto a QR code was able to detect 0.0005% v/v of H2O2 in aqueous samples. The QR integrated chromogenic paper strip sensors can serve as a useful tool for consumers, regulatory agencies, and the food industry to assess food quality and authenticity.

Recent Advances In the development of enzymatic paper-based microfluidic biosensors

Using microfluidic paper-based analytical devices has attracted considerable attention in recent years. This is mainly due to their low cost, availability, portability, simple design, high selectivity, and sensitivity. Owing to their specific substrates and catalytic functions, enzymes are the most commonly used bioactive agents in μPADs. Enzymatic μPADs are various in design, fabrication, and detection methods. This paper provides a comprehensive review of the development of enzymatic μPADs by considering the methods of detection and fabrication. Particularly, techniques for mass production of these enzymatic μPADs for use in different fields such as medicine, environment, agriculture, and food industries are critically discussed. This paper aims to provide a critical review of μPADs and discuss different fabrication methods as the central parts of the μPADs production categorized into printable and non-printable methods. In addition, state-of-the-art technologies such as fully printed enzymatic μPADs for rapid, low-cost, and mass production and improvement have been considered.

Paper-based optical sensors paired with smartphones for biomedical analysis

The traditional analytical methods used for biomedical analysis are expensive and not easy to handle and require sophisticated instruments, thus their application is limited in resource-limited settings. Due to their portability, low cost, and ability to be applied to different analytical techniques, paper-based analytical devices are becoming valuable tools for biomedical analysis. The integration of smartphones into analytical devices has provided the ability to build portable, cost-effective, straightforward analytical devices for biomedical analysis and mobile health. The key aim of this review is to emphasize the recent applications of PADs combined with a smartphone for the optical analysis of biomedical species. We started this review by highlighting the type of papers and their modifications with different materials to prepare the PADs. After that, this review presents various detection methods including colorimetry, fluorescence, and luminescence where the smartphone is used for read-out. In the end, we provided the recent applications of the analysis of different biomedical compounds such as cancer and cardiovascular biomarkers, metal ions, glucose, viruses, etc. We believe that the present review will attract a wide scientific community in the areas of analytical chemistry, sensors, and clinical testing.

Smartphone-Facilitated Mobile Colorimetric Probes for Rapid Monitoring of Chemical Contaminations in Food: Advances and Outlook

Smartphone-derived colorimetric tools have the potential to revolutionize food safety control by enabling citizens to carry out monitoring assays. To realize this, it is of paramount significance to recognize recent study efforts and figure out important technology gaps in terms of food security. Driven by international connectivity and the extensive distribution of smartphones, along with their built-in probes and powerful computing abilities, smartphone-based sensors have shown enormous potential as cost-effective and portable diagnostic scaffolds for point-of-need tests. Meantime, the colorimetric technique is of particular notice because of its benefits of rapidity, simplicity, and high universality. In this study, we tried to outline various colorimetric platforms using smartphone technology, elucidate their principles, and explore their applications in detecting target analytes (pesticide residues, antibiotic residues, metal ions, pathogenic bacteria, toxins, and mycotoxins) considering their sensitivity and multiplexing capability. Challenges and desired future perspectives for cost-effective, accurate, reliable, and multi-functions smartphone-based colorimetric tools have also been debated.

The Road to Unconventional Detections: Paper-Based Microfluidic Chips

Conventional detectors are mostly made up of complicated structures that are hard to use. A paper-based microfluidic chip, however, combines the advantages of being small, efficient, easy to process, and environmentally friendly. The paper-based microfluidic chips for biomedical applications focus on efficiency, accuracy, integration, and innovation. Therefore, continuous progress is observed in the transition from single-channel detection to multi-channel detection and in the shift from qualitative detection to quantitative detection. These developments improved the efficiency and accuracy of single-cell substance detection. Paper-based microfluidic chips can provide insight into a variety of fields, including biomedicine and other related fields. This review looks at how paper-based microfluidic chips are prepared, analyzed, and used to help with both biomedical development and functional integration, ideally at the same time.

Smartphone-based mobile biosensors for the point-of-care testing of human metabolites

Rapid, accurate, portable and quantitative profiling of metabolic biomarkers is of great importance for disease diagnosis and prognosis. The recent development in the optical and electric biosensors based on the smartphone is promising for profiling of metabolites with advantages of rapid, reliability, accuracy, low-cost and multi-analytes analysis capability. In this review, we introduced the optical biosensing platforms including colorimetric, fluorescent and chemiluminescent sensing, and electrochemical biosensing platforms including wired and wireless communication. Challenges and future perspectives desired for reliable, accurate, cost-effective, and multi-functions smartphone-based biosensing systems were also discussed. We envision that such smartphone-based biosensing platforms will allow daily and comprehensive metabolites monitoring in the future, thus unlocking the potential to transform clinical diagnostics into non-clinical self-testing. We also believed that this progress report will encourage future research to develop advanced, integrated and multi-functional smartphone-based Point-of-Care testing (POCT) biosensors for the monitoring and diagnosis as well as personalized treatments of a spectrum of metabolic-disorder related diseases.

All-printed semiquantitative paper-based analytical devices relying on QR code array readout

Colorimetric assay enabling user independent semiquantitative result readout through an array of sequentially unmasked QR codes.

Paper-Based Microfluidic Device (DON-Chip) for Rapid and Low-Cost Deoxynivalenol Quantification in Food, Feed, and Feed Ingredients

Mycotoxin contamination causes over $5 billion of economic loss per year in the North American food and feed industry. A rapid, low-cost, portable, and reliable method for on-site detection of deoxynivalenol (DON), a representative mycotoxin predominantly occurring in grains, would be helpful to control mycotoxin contamination. In this study, a paper-based microfluidic chip capable of measuring DON (DON-Chip) in food, feed, and feed ingredients was developed. The DON-Chip incorporated a colorimetric competitive immunoassay into a paper microfluidic device and used gold nanoparticles as a signal indicator. Furthermore, a novel ratiometric analysis method was proposed to improve detection resolvability. Detection of DON in the aqueous extracts from solid food, feed, or feed ingredients was successfully validated with a detection range of 0.01-20 ppm (using dilution factors from 10 to 10⁴). Compared with conventional methods, the DON-Chip method could greatly reduce the cost and time of mycotoxin detection in the food and feed industry.