The Application of Graphene Field-Effect Transistor Biosensors in COVID-19 Detection Technology: A Review

Poly(3,4-ethylenedioxythiophene) Nanorod Arrays-Based Organic Electrochemical Transistor for SARS-CoV-2 Spike Protein Detection in Artificial Saliva

The outbreak and continued spread of coronavirus disease 2019 (COVID-19) have significantly threatened public health. Antibody testing is essential for infection diagnosis, seroepidemiological analysis, and vaccine evaluation. However, achieving convenient, fast, and accurate detection remains challenging in this prolonged battle. This study reports a highly sensitive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein detection platform based on organic electrochemical transistors (OECTs) for biosensing applications. We developed a nanostructured poly(3,4-ethylenedioxythiophene) (PEDOT) conductive polymer with the carboxylic acid functional group (PEDOTAc) for modifying specific antibodies on an OECT channel for the detection of the COVID-19 spike protein. The OECT device features a channel composed of a PEDOT:polystyrenesulfonate (PEDOT:PSS) bottom layer, with the upper layer decorated with PEDOTAc nanorod arrays via the oxidative polymerization and a trans-printing method. Our novel PEDOTAc nanorod array-based OECT device exhibits promising potential for future healthcare and point-of-care sensing due to its rapid response, high sensitivity, and high accuracy. Through optimization, we achieved specific detection of the SARS-CoV-2 spike protein within minutes, with a detectable region from 10 fM to 100 nM. These biosensors hold significant promise for use in the diagnosis and prognosis of COVID-19.

Nanomaterials in point-of-care diagnostics: Bridging the gap between laboratory and clinical practice

The integration of nanomaterials into biosensing technologies represents a paradigm shift in medical diagnostics and environmental monitoring, marking a significant advancement in the field. This comprehensive review examines the role of nanomaterials, such as gold nanoparticles, carbon nanotubes, graphene, and quantum dots, in enhancing the performance of biosensors. These nanomaterials contribute unique physical and chemical properties, including exceptional electrical, optical, and thermal conductivities, which significantly improve the sensitivity, specificity, and versatility of biosensors. The review provides an in-depth analysis of the mechanisms by which these nanomaterials enhance biosensor functionality, including increased surface-to-volume ratio, improved electron transfer rates, and enhanced signal transduction. The practical applications of these advanced biosensors are explored across various domains, including oncology, infectious diseases, diabetes management, cardiovascular health, and neurodegenerative conditions, emphasizing their role in early disease detection, real-time health monitoring, and personalized medicine. Furthermore, the review addresses the critical challenges and limitations facing the field, such as biocompatibility, biofouling, stability, and integration into existing healthcare systems. Strategies to overcome these challenges, including advanced material engineering and novel fabrication techniques, are discussed. The future of nanomaterial-based biosensors is envisioned through the lens of emerging trends and technological innovations. The integration with microfluidics, artificial intelligence, and wearable technology is highlighted as a path toward more personalized, efficient, and accessible healthcare solutions. This review underscores the transformative impact of nanomaterials in biosensing, projecting a future where these advanced technologies play a pivotal role in reshaping diagnostics, patient care, and environmental monitoring, thereby significantly enhancing healthcare and public health outcomes.

Laser-Induced Graphene for Advanced Sensing: Comprehensive Review of Applications

Laser-induced graphene (LIG) and Laser-scribed graphene (LSG) are both advanced materials with significant potential in various applications, particularly in the field of sustainable sensors. The practical uses of LIG (LSG), which include gas detection, biological process monitoring, strain assessment, and environmental variable tracking, are thoroughly examined in this review paper. Its tunable characteristics distinguish LIG (LSG), which is developed from accurate laser beam modulation on polymeric substrates, and they are essential in advancing sensing technologies in many applications. The recent advances in LIG (LSG) applications include energy storage, biosensing, and electronics by steadily advancing efficiency and versatility. The remarkable flexibility of LIG (LSG) and its transformative potential in regard to sensor manufacturing and utilization are highlighted in this manuscript. Moreover, it thoroughly examines the various fabrication methods used in LIG (LSG) production, highlighting precision and adaptability. This review navigates the difficulties that are encountered in regard to implementing LIG sensors and looks ahead to future developments that will propel the industry forward. This paper provides a comprehensive summary of the latest research in LIG (LSG) and elucidates this innovative material's advanced and sustainable elements.

The importance, benefits, and future of nanobiosensors for infectious diseases

Infectious diseases, caused by pathogenic microorganisms such as bacteria, viruses, parasites, or fungi, are crucial for efficient disease management, reducing morbidity and mortality rates and controlling disease spread. Traditional laboratory-based diagnostic methods face challenges such as high costs, time consumption, and a lack of trained personnel in resource-poor settings. Diagnostic biosensors have gained momentum as a potential solution, offering advantages such as low cost, high sensitivity, ease of use, and portability. Nanobiosensors are a promising tool for detecting and diagnosing infectious diseases such as coronavirus disease, human immunodeficiency virus, and hepatitis. These sensors use nanostructured carbon nanotubes, graphene, and nanoparticles to detect specific biomarkers or pathogens. They operate through mechanisms like the lateral flow test platform, where a sample containing the biomarker or pathogen is applied to a test strip. If present, the sample binds to specific recognition probes on the strip, indicating a positive result. This binding event is visualized through a colored line. This review discusses the importance, benefits, and potential of nanobiosensors in detecting infectious diseases.