Recent trends in the development of complementary metal oxide semiconductor image sensors to detect foodborne bacterial pathogens

Paper-based diagnostic chips for viral detection

Viruses cause various diseases in humans, and pose serious health risks to individuals and populations worldwide. As a result, various diagnostic procedures and methods have been developed to prevent, manage, and reduce the burden of viral diseases, each with its own benefits and drawbacks. Among these, paper-based diagnostic chips are becoming increasingly common because of their speed, accuracy, convenience, and economical and environmental friendliness. These paper-based diagnostic tests have ideal point-of-care (POC) diagnostic applications, particularly in personalized healthcare. Paper-based diagnostics have emerged as innovative and low-cost solutions for diagnosing viral diseases in remote and underdeveloped regions where traditional diagnostic methods are not readily available. These tests are easy to use, require minimal equipment, and can be performed by nonspecialized personnel, making them accessible even in resource-constrained settings. In this review, we discuss recent developments in paper-based diagnostic chips, the importance of improved methods for identifying viral pathogens, drawbacks of traditional detection techniques, and challenges and prospects of paper-based diagnostic chips for the detection of viruses.

Coupling Bifunctional Nanozyme-Mediated Catalytic Signal Amplification and Label-Free SERS with Immunoassays for Ultrasensitive Detection of Pathogens in Milk Samples

Rapid and sensitive detection of foodborne bacteria is of great significance in guaranteeing food safety and preventing foodborne diseases. A bifunctional Au@Pt core-shell nanozyme with excellent catalytic properties and high surface-enhanced Raman scattering (SERS) activity was developed for the highly sensitive detection of Salmonella typhimurium based on a label-free SERS strategy. The ultrathin Pt shell (about 1 nm) can catalyze Raman-inactive molecules into Raman-active reporters, greatly amplifying the amount of signal molecules. Moreover, the Au core serves as an active SERS substrate to enhance the signal of reporter molecules, further significantly improving the detection sensitivity. Benefiting from the excellent properties, such a bifunctional Au@Pt nanozyme was integrated with a magnetic immunoassay to construct a label-free SERS platform for the highly sensitive detection of S. typhi with a low detection limit of 10 CFU mL^-1. Also, the Au@Pt-based SERS platform exhibited excellent selectivity and was successfully utilized for the detection of S. typhi in milk samples by a portable Raman spectrometer. Our demonstration of the bifunctional nanozyme-based SERS strategy provides an efficient pathway to improve the sensitivity of label-free SERS detection of pathogens and holds great promise in food safety, environmental analysis, and other biosensing fields.

Salmonella typhimurium strip based on the photothermal effect and catalytic color overlap of PB@Au nanocomposite

This work reports a sensitive and accurate multimode detection method to detect Salmonella typhimurium using inherent color, photothermal and catalytic properties of Prussian blue@gold nanoparticles (PB@Au). The inherent color of PB@Au can realize direct visual detection while the temperature increase (ΔT) of it can realize sensitive and quantitative photothermal detection. Moreover, catalytic coloration detection is applied to further amplify detection signal. The risk limit, prevention and control of Salmonella typhimurium can be more intuitively displayed through catalytic color overlap degree between PB@Au and catalytic product. The sensitivity of method is improved through photothermal and catalytic coloration detection (10¹ CFU·mL^-1) compared with direct visual detection (10² CFU·mL^-1). The multimode detection improves the accuracy of method, and exhibits good repeatability, acceptable selectivity and stability. This method is also successfully applied in real samples, displaying its good practical applicability.

A multifunctional colorimetric sensor array for bacterial identification and real-time bacterial elimination to prevent bacterial contamination

The constructed sensor array has simple operation and successfully integrates bacterial identification and inactivation.

Towards Fully Integrated Portable Sensing Devices for COVID-19 and Future Global Hazards: Recent Advances, Challenges, and Prospects

Since the onset of the coronavirus disease 2019 (COVID-19) pandemic, this fatal disease has been the leading cause of the death of more than 3.9 million people around the world. This tragedy taught us that we should be well-prepared to control the spread of such infectious diseases and prevent future hazards. As a consequence, this pandemic has drawn the attention of many researchers to the development of portable platforms with short hands-on and turnaround time suitable for batch production in urgent pandemic situations such as that of COVID-19. Two main groups of diagnostic assays have been reported for the detection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) including nucleic acid-based and protein-based assays. The main focus of this paper is on the latter, which requires a shorter time duration, less skilled technicians, and faces lower contamination. Furthermore, this paper gives an overview of the complementary metal-oxide-semiconductor (CMOS) biosensors, which are potentially useful for implementing point-of-care (PoC) platforms based on such assays. CMOS technology, as a predominant technology for the fabrication of integrated circuits, is a promising candidate for the development of PoC devices by offering the advantages of reliability, accessibility, scalability, low power consumption, and distinct cost.

Construction of Zn/Ni Bimetallic Organic Framework Derived ZnO/NiO Heterostructure with Superior N-Propanol Sensing Performance

Bimetallic organic frameworks (Bi-MOFs) have been recognized as one of the most ideal precursors to construct metal oxide semiconductor (MOS) composites, owing to their high surface area, various chemical structures, and easy removal of the sacrificial MOF scaffolds through calcination. Herein, we synthesized Zn/Ni Bi-MOF for the first time via a facile ion exchange postsynthetic strategy, formed a three-dimensional framework consisting of infinite one-dimensional chains that is unattainable through the direct solvothermal approach, and then transformed the Zn/Ni Bi-MOF into a unique ZnO/NiO heterostructure through calcination. Notably, the obtained sensor based on a ZnO/NiO heterostructure exhibits an ultrahigh response of 280.2 toward 500 ppm n-propanol at 275 °C (17.2-fold enhancement compared with that of ZnO), remarkable selectivity, and a limit of detection of 200 ppb with a notable response (2.51), which outperforms state-of-the-art n-propanol sensors. The enhanced n-propanol sensing properties may be attributed to the synergistic effects of several points including the heterojunction at the interface between the NiO and ZnO nanoparticles, especially a one-dimensional chain MOF template structure as well as the chemical sensitization effect of NiO. This work provides a promising strategy for the development of a novel Bi-MOF-derived MOS heterostructure or homostructure with well-defined morphology and composition that can be applied to the fields of gas sensing, energy storage, and catalysis.

Recent trends in the utilization of LAMP for the diagnosis of viruses, bacteria, and allergens in food

Foodborne diseases are becoming major scientific struggles for both developing and developed countries. Most foodborne infections are caused by microbial pathogens such as bacteria, viruses, and other food allergens. Hence early and accurate diagnosis of these foodborne pathogens is always preferable. To satisfy these concerns, plenty of isothermal amplification methodologies such as rolling circle amplification (RCA), helicase-dependent amplification (HDA), and recombinase polymerase amplification (RPA) have been developed. Among these, loop-mediated isothermal amplification (LAMP) is a widely usable, potential, and recognizable amplification technique achieved at a constant temperature around 60°C within 30–60 min by using only one kind of enzyme. As a robust gene amplification technique, it can be employed for the detection of bacteria, viruses, and other related food allergens. This technique has its own merits such as cost-effectiveness, facile manufacturing procedure, and consistency. In this chapter, we emphasize recent trends in designing the techniques, challenges, and the future prospects of LAMP in the detection of foodborne pathogens. These effective pathogen detection methods may offer potential benefits compared with existing conventional methods.

Applications of CMOS Devices for the Diagnosis and Control of Infectious Diseases

Emerging infectious diseases such as coronavirus disease of 2019 (COVID-19), Ebola, influenza A, severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) in recent years have threatened the health and security of the global community as one of the greatest factors of mortality in the world. Accurate and immediate diagnosis of infectious agents and symptoms is a key to control the outbreak of these diseases. Rapid advances in complementary metal-oxide-semiconductor (CMOS) technology offers great advantages like high accuracy, high throughput and rapid measurements in biomedical research and disease diagnosis. These features as well as low cost, low power and scalability of CMOS technology can pave the way for the development of powerful devices such as point-of-care (PoC) systems, lab-on-chip (LoC) platforms and symptom screening devices for accurate and timely diagnosis of infectious diseases. This paper is an overview of different CMOS-based devices such as optical, electrochemical, magnetic and mechanical sensors developed by researchers to mitigate the problems associated with these diseases.