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Biosensors for Infectious Diseases-Fundamentals

Maheswata Moharana1, Subrat K. Pattanayak1, Fahmida Khan1, and Sushma Dave2

1National Institute of Technology, Department of Chemistry, Raipur, 492010, India

2Jodhpur Institute of Engineering and Technology, Department of Applied Sciences, Jodhpur, 342802, India

1.1 Introduction

The rapid growth in the urbanization processes and its association with inadequate city planning, poor management of sanitary conditions as well as water supplies, high population density, and interference in previously unaffected ecosystem leads to the spread of infectious diseases [1]. The term "infectious diseases" refers to medical conditions caused by a variety of pathogenic microorganisms, which include bacteria, viruses, fungi, and parasites. The diseases can spread from one organism to another through direct or indirect contact that results in a number of ailments, some of which are fatal [2]. Infectious disease outbreaks continue to put a heavy burden on the world's population despite the surge in medical advancements. They consistently pose challenges to international healthcare systems, raising ongoing concern about the rising frequency of epidemics throughout the world. It was reported, in 2016, the infectious diseases were responsible for one-fifth of all deaths that were officially recorded worldwide. In addition, socioeconomic and environmental issues, such as climate change, migration, and population increase, will probably make this scenario worse, particularly in overpopulated places. The need for early detection systems has grown as the possibility of more frequent epidemics and disease outbreaks has increased. An illustration of the necessity for early detection techniques to track diseases outbreaks is the continuing COVID-19 pandemic brought on by the rapid transmission of the novel coronavirus [3]. The success of measures for disease zoning, control, or eradication is greatly influenced by the rapid detection of a virus or antigen due to the threat posed by infectious diseases. All public-health programs must include both disease surveillance and diagnosis as essential elements. Prior to a virus outbreak having disastrous effects on the economy, people, and the environment, it is crucial to stop it from spreading or minimizing its speed [4]. Infectious diseases are categorized as (i) severe respiratory syndrome, which falls into the category of novel and previously unknown diseases, (ii) Foot and mouth diseases, on the other hand, fall into the category of recognized diseases that have risen in incidence, virulence, or in certain geographic range, and (iii) diseases such as avian influenza that are expected to become more prevalent in recent future [4]. In some cases, the diseases can spread through in a community in just a few hours, depending on the types of infectious diseases and the surrounding weather. The ongoing COVID-19 pandemic serves as a stark reminder: within two years of its emergence, more than 4.6?million lives have been lost, and the cost to the world economy is approaching US$7?trillion [5]. Finding the pathogens that cause infectious diseases is the first step in controlling them. By using an agar plate to grow bacteria on Petri's invention, Dr. Koch altered how we view diseases (i.e. the Petri dish). Laboratory culture-based detection of infectious agents has evolved into the "gold standard" in clinical microbiology. When combined with his novel microscopy, the technique enabled to link pathogens as the source of diseases commonly known as Koch's postulates [6]. Another significant development was introduced known as polymerase chain reaction (PCR), which includes the increase of detection limits of the infectious agents, even those that were slow-growing or uncultivable [7]. The diagnostic procedures are restricted only to the centralized medical laboratories due to the need for supporting infrastructure, such as highly skilled employees and capital equipment to perform PCR and culture assays. We need to make next technological leap to fast, economical, yet highly accurate diagnostic tests to better deal with infections that is emerging rapidly. The biosensor is one alluring device that can offer quick information on a disease outbreak [8]. It is commonly known that biosensors play a key role in environmental monitoring [9, 10], agriculture [11, 12], food and water analysis [13, 14], and medicine/clinical analysis [15, 16].

1.2 Biosensors Fundamental Aspects

Biosensors have a variety of definitions in the literature. However, according to 1999 IUPAC standards, they can be defined as a self-contained integrated receptor-transducer system that may provide specific quantitative or semiqualitative analytical information utilizing a biological recognition element [17]. Ideally, the biosensor should be a reagentless device that is typically employed in the detection process with the noble purpose of providing quick, accurate, and reliable information about the biochemical composition of its environment. It should also be able to respond continuously, reversibly, and without disrupting the sample. Different types of biosensors are available [18-21]. However, all of them essentially consist of a biological recognition component, or bioreceptor which interacts with the analytes to be detected and generates signals by the means of signal processing unit or transducer. A schematic representation of the typical components of biosensor is shown in Figure 1.1. An enzyme, antibody, nucleic acid (NA), cell/tissue, and hormones can be employed as bio-component. Its function is to selectively interact with the target analytes, and the outcome of the biochemical process is then turned into quantifiable signal through the transducer [22]. There are several types of transducing systems, including electrochemical, optical, piezoelectric, thermometric, and magnetic [23]. A "biosensor" is a device used to measure for analyte detection that combines a biological and physicochemical detector linked to a component. The design as well as function of biosensor determines the analyte detection. A noninvasive smartphone-based analyte biosensor can be tested on smartphones and other widely used devices. This enables rapid and cost-effective preliminary detection possible.

Figure 1.1 The schematic of biosensor concept representation.

1.3 Classifications of Biosensor

In the late 1960s, Clarke and Lyons developed biosensors [24]. There are several perspectives to categorize biosensors, but the most frequently used two are biorecognition component and the signal transduction component. Based on the above two categories, biosensors classification is summarized in Table 1.1.

Table 1.1 Classification of biosensors based on biorecognition elements and transduction perspective.

1.3.1 Biorecognition Perspective

Biosensors are categorized as nucleic acid, protein receptor-based immunosensors, enzymatic biosensors, and whole-cell biosensors based on the biological recognition component. The details of principles as well as examples are discussed in Sections 1.3.1.1-1.3.1.5.

1.3.1.1 Nucleic Acid Biosensors

A nucleic acid-based biosensor uses a complex DNA or RNA structure or an oligonucleotide with a known base sequence as detecting element. Nucleic acid biosensors can be used to find biological or chemical species, as well as DNA/RNA fragments. The analytes in the first application are DNA/RNA, and the hybridization reaction is used to detect it (a type of genosensor). In the second case, DNA/RNA acts as a receptor for particular biological/chemical species, such as drugs,...