**6. Conclusions and prospects**

Without any doubt, environmental monitoring and food safety are the main universal worries that we humans have to oppose and are constantly struggling to take them over. In this chapter, we evidently demonstrated the principle and development phage-based biosensor. We compared the conventional phage based detection methods and briefed an introduction to different bio-probes involved in biosensors development. Further, we reviewed demonstrative phage/phage-components used in sensors development for pathogenic bacterial detection. Finally, we briefed different techniques to immobilize phages on appropriate substrate that is the major step toward phage-based biosensor development. We intend at thought-provoking and comprehensive explanations in mounting phage-based sensors and enlightening their uses for bacterial detection. By collaboration of engineers and scientists from multidisciplinary area to design a field applicable sensor and make advancements in phage-based sensors for bacterial pathogens diagnosis, we expect that this

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*Principle and Development of Phage-Based Biosensors DOI: http://dx.doi.org/10.5772/intechopen.86419*

ing and infectious disease diagnostics is vital as they are;

• Cheap (based on easy phages production)

• Versatile (based on phage components)

ELISA enzyme linked immunosorbent assay ITNAA isothermal nucleic acid amplification

qPCR quantitative polymerase chain reaction

IUPAC International Union of Pure and Applied Chemistry

• Highly specific

• Very sensitive

**Acknowledgements**

**Acronyms and abbreviations**

LOD limit of detection

QDs quantum dots

PCR polymerase chain reaction

RBPs receptor-binding proteins BCCP biotin-carboxyl-carrier-protein CBM cellulose-binding-module SOCP small-outer-capsid-protein

Abs antibodies *E. coli Escherichia coli*

Valley of China.

chapter might bring together the technologies related to phage-based sensors. In short, phage based biosensors in the fields of food safety, environmental monitor-

This work was supported by National Key Research and Development Program of China under Grant 2017YFC1104402, China Postdoctoral Science Foundation (2016 M602291), the initial Research fund from CSC; and 3551 Project, Optics

*Principle and Development of Phage-Based Biosensors DOI: http://dx.doi.org/10.5772/intechopen.86419*

chapter might bring together the technologies related to phage-based sensors. In short, phage based biosensors in the fields of food safety, environmental monitoring and infectious disease diagnostics is vital as they are;


*Biosensors for Environmental Monitoring*

**5.3 Phage entrapment in porous matrix**

**5.4 Phage layer by layer organization**

Bacteriophages immobilization in micro-porous matrices permits them functionally and also structurally stable, keeping them active for long time period. Phages immobilization by entrapment in a porous hydrogel, (bio)polymeric agar and alginate matrices, is a tool for selection of applications where protection of phage particles essential against severe environmental conditions [62]. Additionally, entrapment might aid to maintain moisture, which is important for many phages infectivity, or keep phage particles in lyophilized condition [63]. A fruitful marketable case in point of entrapped bacteriophage in matrix is PhagoBioDerm [64] that is 0.2 mm thick, porous-polymericwound-dressing saturated with a mixture of biocides and lytic phages [65]. The matrices used for bacteriophage entrapment, that might possibly delay interaction of entrapped bacteriophage particles with host bacterial cells or analytes that are present in

the vicinity of medium [66], marking inefficiency of phage bioactive surface.

diffuse freely form a nearby packed phage monolayer [69].

on the working principle of selected transduction platform.

**6. Conclusions and prospects**

**5.5 Efficiency of immobilized phages in biosensing platforms**

Many investigators discovered to possibly immobilize phages by alternative layering with polyelectrolytes having oppositely charges, and claimed observation of enhanced phage particle surface coverage [68, 69]. For instance, a layer by layer methodology for M13 bacteriophage was reported, and phage was sandwiched between oppositely charged layers of weak poly-electrolytes, that was capable to

The effectiveness of bio-sensing approaches is mostly measured in terms of minimum limit of detection (LOD) of bacterial or other analyte. Thus researchers attempted and focused to improve the bacteriophage surface coverage for pushing detection limits. Significantly keep in mind that the LOD has not been improved biosensors where phages are immobilized by covalent binding, in comparison to the approaches where phage is immobilized by physisorption [22]. Thus, bacteriophage surface coverage is not only the factor to necessarily increase and improve the sensitivity and LOD of bacteriophage-based biosensor. Limit of detection of biosensors, based on various transduction approaches can be different depending

Without any doubt, environmental monitoring and food safety are the main universal worries that we humans have to oppose and are constantly struggling to take them over. In this chapter, we evidently demonstrated the principle and development phage-based biosensor. We compared the conventional phage based detection methods and briefed an introduction to different bio-probes involved in biosensors development. Further, we reviewed demonstrative phage/phage-components used in sensors development for pathogenic bacterial detection. Finally, we briefed different techniques to immobilize phages on appropriate substrate that is the major step toward phage-based biosensor development. We intend at thought-provoking and comprehensive explanations in mounting phage-based sensors and enlightening their uses for bacterial detection. By collaboration of engineers and scientists from multidisciplinary area to design a field applicable sensor and make advancements in phage-based sensors for bacterial pathogens diagnosis, we expect that this

**166**

