An insight in bacteriophage based biosensors with focus on their detection methods and recent advancements

Highlights

• Effective detection of pathogenic bacteria is possible through Bacteriophage biosensors.

• Different types of bio-probes associate with the biosensors for promising results.

• Bacteriophage-based biosensor systems are efficient under different environment conditions.

• Phage-based biosensors overcome the downsides of conventional pathogen detection strategies.

Abstract

Pathogenic bacteria have become a global issue and has affected various sectors like food, health and environmental monitoring, which has made the detection and identification of these pathogenic bacteria of utmost importance. Bacterial infections are the leading cause of most fatalities, often due to delay in diagnosis or misdiagnosis. Therefore, pathogenicity assessment of these bacteria has become crucial in understanding the disease dynamics. Although, conventional bacterial identification and characterization techniques like microscopic and molecular methods are available, being cost-intensive, time-consuming and tedious, makes it unsuitable for rapid analysis. There are raising concern about bacterial detection and pathogenicity assessment, which has prompted the researchers to exploit and develop biosensors derived from diverse bio-probes like enzymes, RNA, DNA, antibodies etc. However, bacteriophage-based biosensor system offers numerous advantages like cost-effectiveness, high affinity, high specificity, more stability and resistance towards various environmental factors like ion concentrations, pH and temperature. Therefore, the current review intends to highlight different bacterial detection techniques and facilitate with the basics of the biosensor. Additionally, it also discusses the different bio-probes used for biosensor development. Furthermore, it will also discuss the different types of phage-based biosensors and their importance.

Introduction

Bacterial contamination has become the global issue as it has obstructed the socio-economic stability of environment, food and healthcare system (LeJeune and Rajala-Schultz, 2009, Mead et al., 1999, Roca et al., 2015). The conventional approaches have been found to show ineffective results in a complex mixture of microbes and underline the lack of enrichment step in environmental conditions (Kumar Awasthi et al., 2020). The conventional approaches behold plating techniques and antibodies-based assays, which makes it clear why these methods are inefficient, less sensitive to distinct the targeted microbes from the environmental sample (Ezem, 2007). Whereas, methods like enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) have sensitivity in determining the target microbes from the sample but are unable to distinguish that the cells are viable or not (Daly et al., 2002). Therefore, it demands the up-gradation for sensitivity and specificity but in return, makes it expensive and laborious. All these challenges could be resolved with the development of biosensor (Balasubramanian et al., 2007). For developing biosensor, sensitivity and specificity of bio-probe are of utmost importance, so that it could withstand at high temperature, extreme pH and remains active in harsh environment (Pandey et al., 2014).

Recently, bacteriophage has gained the significant attention due to its specificity as well as sensitivity towards the targeted microbes and remains active in diverse conditions makes it the potential candidate for developing biosensor for bacterial detection (Koskella and Meaden, 2013). Phages naturally possess the ability to specifically recognize the specific bacterial strain for its attachment. Therefore, rapid-recognition offered by these bacteriophages can be used in developing a biosensor to improve their ability to trace and remediate bacterial contamination. Bacteriophage based biosensors have also been developed for wide range of applications in environmental remediation and contamination detection such as toxins, environmental pollutants and pathogens. Recent development in the field of genetic engineering, engineered phages are used for tracking the source of pollution in various environmental conditions and the analysis is based on identification of unique sequence and plaque assay (Daniell et al., 2000). They have emerged as important key elements in governing the function and structure of microbial communities (Kauffman et al., 2018).

Bacteriophages based biosensor has also been used for the identification of foodborne pathogens. In addition, magnetoelastic biosensors (multiple phage-based) have been used in the detection of various biological pathogens in real samples or complex analytes (Farooq et al., 2019). The major obstruction which comes into the picture is the active and oriented phages immobilization of the phages on the substrate surface (Maniatis et al., 1975). The major benefit of immobilizing the bacteriophage on the substrate surface of the biosensor is that phages remain functioning for a long period of time, have high bacterial capturing efficacy and sustain physiological activities at high densities. Hence, highlighting its detection limit and promoting the development of a phage-based biosensor for robust and precise bacterial detection (Stewart et al., 1998). The hypothesis for the current study was to focus on phage-based biosensor having exclusive approaches including (a) Assessment of phage like particle release during lytic cycle along with host bacterium, (b) Monitoring of lysed cell component release during phage intermediated lysis of host bacterium, (c) Assessment of inhibition of bacterial growth in the presence of particular phage, (d) Assessment of bacterial capture via stained phages and (e) Monitoring of expression of reporter gene cloned in genetically modified phage which expresses on the bacterial infection. The present review summarizes the current status of knowledge in the direction related to bacterial detection techniques and elaborate understanding along with the basics of the biosensor. Additionally, it also discusses the use of different bio-probes in biosensor development. Furthermore, it will also discuss the different types of phage-based biosensor, their advantages and their limitations.