Salivary diagnostics offers a promising method for early diagnosis, prognosis, and post-therapy monitoring. Saliva contains various hormones, proteins, enzymes, antibodies, antimicrobial constituents, and cytokines that can provide diagnostic information. Saliva is easy to collect, non- invasive, cost-effective, and can be easily stored and transported, making it a valuable tool for diagnosis and monitoring of various diseases. Salivary biomarkers can be used for early detection, diagnosis, and monitoring of disease progression, as well as predicting treatment response. Saliva has been identified as a promising diagnostic fluid for detecting various oral diseases such as dental caries, periodontal disease, and oral cancer. This review explores the latest advancements in identifying biomarkers for prevalent oral diseases and the biosensing technologies that can detect these biomarkers with enhanced sensitivity, selectivity, accuracy, and practicality.

The human immune system is a complex network of cells, tissues, and organs that work together to protect the body from harmful pathogens. Antibodies, also known as immunoglobulins (Ig), are small proteins that play a vital role in the immune system's defense mechanism. Among the five classes of immunoglobulins, Immunoglobin G (IgG) is the most abundant and widely studied. This article provides an in-depth overview of the basics of IgG, including their chemical and physical properties and their roles in the human immune system. The article then focuses on the critical biosensor working principles with an emphasis on electrochemical biosensors. Biosensors are analytical devices that convert a biological response into an electrical signal, allowing for rapid and sensitive detection of specific analytes. The use of biosensors for IgG detection has gained significant attention in recent years due to their sensitivity, specificity, and ability to detect IgG in real-time. This article also discusses many novel strategies that have been reported in the literature for sensitive IgG detection. These strategies include the use of different biorecognition elements, such as antibodies, aptamers, enzymes, and biomimetic materials. Moreover, the article concludes by highlighting recent research advances and future directions for sensitive IgG detection, such as the use of nanomaterials and adaptable machine learning models, leading to a more efficient method of IgG detection.

In this study, the authors presented a simple and cost-effective method for fabricating a carbon nanotubes (CNTs)-based paper-based sensing device via screen printing to determine solution pH. CNTs were chosen due to their high surface area and excellent mechanical and electrical properties, making them useful for various applications, including biological and chemical sensing. The paper-based device was fabricated using paper, a low-cost and accessible substrate, which also has a porous structure for capillary action. The hydrophobic and hydrophilic regions were established using wax printing and paper surface plasmon treatment to control the dimensions of the sensing channels. The CNTs ink was screen printed onto the paper, and the length and width of the sensing channels were controlled by the hydrophobic pattern design and mask design. The amount of CNTs printed was also easily controlled by varying the concentrations of the carbon ink. The resulting CNT-based films on paper were repeatedly produced with a homogeneous thickness. The fabricated sensors showed a linear response range from pH 3 to pH 10, with an optimal L/W ratio of 4, and an electrical signal was generated by measuring the channel resistance using conductive silver leads. This screen printing method provides a facile and low-cost approach for fabricating paper-based sensors that can be used for various sensing applications, including point-of-care diagnosis and environmental monitoring.