High specificity, less reagent requirement, swift response time, and high throughput screening make biosensors popular for detecting disease biomarkers, monitoring diseases, drug discovery, and other ecological applications such as the detection of environmental pollutants. Emerging health disorders demand targeted drugs with lower side effects in terms of advancing towards a low medicinal load. Active ingredients present in the different parts of plants and microorganisms have been used for several medical purposes for ages. Recent research has identified multiple promising natural bioactive compounds possessing the potential to mitigate several life-threatening diseases like Cancer, Diabetes, and Neurological disorders. Identifying such bioactive chemicals in the crude extract from various plant sources like leaves, roots, bark, fruits, and seeds, as well as in microbial extracts, is a tedious work that requires complex instrument setups, lengthy methods, and plenty of time, sometimes many years. The development and use of biosensors for natural bioactive moieties can overcome such problems and expedite the drug discovery process. This chapter provides a summary of the available biosensors for bioactive chemicals detection in extracts and fractions of organisms/plants, their types, design, and methods used for that purpose. Moreover, the chapter highlights the current use and the progress of the development of biosensors for identifying bioactive natural compounds. 

These days, wearable biosensors are a very valuable tool for tracking the start of various acute and chronic diseases. Wearable biosensors (WBSs) are small, electrical devices that coordinate and collect sensations into the human body and can be present in the form of tattoos, gloves, clothing and inserts. WBSs are a flexible and practical tool for use in the healthcare industry, thanks to their ability to detect information, record it and estimate it accurately. WBSs help patients and doctors to communicate in both directions. It is simple to do painless evaluations of bodily fluids using various biochemical markers such as spit, sweat, skin, and tears. As the continuous state of capabilities of wearable and adaptable sensors continues to advance, the creation of new wearable gadgets that can fill the gap and handle the advantage of human well-being checking and clinical application is advancing. Blood is still the most crucial bio-liquid for assessing a person’s health, even though more attention has been paid to other bodily fluids that are naturally secreted and severe functions that are similar to those of blood. There has been a lot of interest in the capacity of compact biosensing devices to identify the analyte in bio-liquids for the early detection of human well-being.

Three-dimensional (3D) bioprinting technology has become a unique system for tissue regeneration and biosensor development by controlled deposition of bioinks to produce complex constructs. Different bioprinters including laser-assisted and extrusion-based have been introduced and used to produce constructs with high resolution, cell viability and shape fidelity for tissue development. In addition, microfluidic technology, organ-on-a-chip and electrospinning technology are used to produce biosensing products to diagnose and monitor living systems. One of the most critical materials used for bioprinting is bioink. Several bioinks of an advanced level and different compositions have been developed too. Here, we briefly highlighted the characteristics, advantages, and disadvantages of some bioprinters and advanced bioinks that have been developed recently. We also stated some tissue engineering applications with the use of 3D bioprinting. Lastly, we mentioned a few key areas for main focus in the future.

Since the conception of biosensor technology in biomedical research, this field is emerging as a promising and high-throughput tool for neuro-engineering and neurosciences research. It has been postulated that the accumulating property proteins are the basic cause of neurodegenerative diseases, such as Parkinson’s disease, Alzheimer’s disease and prion diseases. Thus, neurodegenerative diseases are also called “protein misfolding disorders”. Biosensors have a wide range of applications in biomedical research, including optical and electrochemical detection of biometal-protein interactions, detection of biomarkers, such as β-amyloids, apolipoprotein, and tau proteins, and microRNA in blood and cerebrospinal fluid in neurodegenerative diseases. These are composed of primary biological recognition elements that convert the chemical signal into the voltage or current that evaluates the physical signal by preparing a plot of sensor response against the analyte concentration. This chapter presents a bird’s eye view on various aspects of progress in biosensor development with special emphasis on their application, including metal-protein interactions studies, detection of neurotransmitters using aptamers and calixarenes, detection of biomarkers proteins, such as α-synuclein for Parkinson’s disease, apolipoprotein, tau and β-amyloid proteins for Alzheimer’s disease, and prion proteins. The chapter also summarizes the novel materials reported for improved biosensor performance. This chapter will be of high relevance to the biological scientists working in neuro-engineering and neurosciences research

The concept of a biosensor was first proposed in 1962 by Clark and Lyons, who developed an oxidase enzyme electrode for the detection of glucose. Since then, the development of nanotechnology has prompted biosensors to evolve and become more specialized for a variety of applications. Currently, at the forefront of science, bio-sensing applications combined with nanotechnology have implications for multiple fields, including medicine, biology, environment, drug delivery, and food safety. In recent decades, bacterial and viral diseases have seriously threatened human safety. Prioritizing the rapid detection of outbreaks, which pose a major threat to the healthcare system and could have a catastrophic socioeconomic impact, will help stop them. Scientists are conducting extensive research to develop sensitive diagnostic techniques and effective medicines.

Over the past few decades, technology has greatly improved, with more accuracy and efficiency in monitoring the blood glucose level of diabetic patients. To monitor the blood glucose level, several glucose biosensors have been developed. However, the accuracy, efficiency, standardization and training of the users in an easy way is still a challenge. Biosensors are a non-invasive method that helps medical workers to find the required doses of insulin for diabetic patients. In this chapter, we will discuss different types of biosensors developed, their working mechanism, and the current scenario of biosensors in diabetes diagnosis

New diagnostic technologies are paper-based sensors that are multifunctional, highly flexible, absorbent, and environmentally friendly. The substrate can be used to design a cost-effective framework for disease detection, prognosis, and surveillance of illnesses that is easy, reliable, and quick in our medical healthcare sector. Paper-based devices are an extremely cheap innovation for fabricating simplified and movable diagnosing processes that can be extremely useful in resource-constrained settings like developing countries, where fully equipped infrastructure and highly skilled medical persons are unavailable. Point-of-care (POC) devices give a significant advantage over traditional procedures for in-situ measurement of illness or disease biomarkers, assisting physicians in making decisions. Paper-based analytical devices that combine paper substrates have become popular point-of-need diagnostics over the last decade. We discuss in this chapter the paper-based analytical biosensors and the classification of paper-based biosensors (PBBs) as Dipstick tests, lateral flow assay (LFAs), microfluidic biosensors, and biosensor devices (transducers and biorecognition elements). Furthermore, paper-based biosensors are used to detect malaria and other diseases. 

Biosensors are an investigative contrivance used to find a chemical substance that combines an organic component with a physicochemical detector. Various biosensors are used in different fields: electrochemical-based, immune-based, magnetic-based, thermometric-based, acoustic-based, enzyme-based, optical-based, DNA-based, and tissue-based, etc. Enzyme-based biosensors are those which use enzymes or proteins for the recognition of elements and adjoining the inbuilt specificity of enzymes. Due to their high sensitivity and specificity, these enzymatic biosensors are frequently used in numerous fields, including the health and biomedical field. This book chapter will describe the various enzyme-based biosensors, their sensitivity and specificity, and their significant applications in different fields. 

Sustainable agriculture has the potential to benefit greatly from nanobiosensors. Nanomaterials are crucial components of numerous biotic and abiotic remediation systems and have a huge impact on the mobility, fate and toxicity of soil contaminants in agriculture. It is believed that nanobiosensor have a revolutionary impact on the field of agriculture by focusing research and development toward the goals of achieving sustainable agriculture. Nanobiosensors have significant benefits such as improved recognition sensitivity or specificity, and retain immense promise for the application of nanobiosensor in various areas such as food quality and bioprocess control, agriculture, biodefense and medical applications. Nanobiosensors application in the agricultural area has significantly improved productivity. The economic and cutting-edge nanobiosensors have been emphasised in this book chapter to address the difficulties in the main agricultural industry and emphasize the significance of nanobiosensor to detect insecticides, herbicides, fertilizers and diseases for increasing crop yield.