**Acknowledgements**

*Biosensors for Environmental Monitoring*

**3.2 Environmental monitoring**

of food like whole milk and ground beef [46].

mL in water with detection time of 60 min [5].

*S. arlettae* in river water [52].

**5. Conclusions and prospects**

**4. Other representative applications**

selectivity toward *L. monocytogenes*. These composites of phage and magnetic particles were further used to selectively isolate *L. monocytogenes* from real sample

For *E. coli* detection in water, a group of authors established and reported a rise in sensitivity of lateral flow assay based on T7 phage amplification. The assay was founded on phage-based reporter proteins: maltose-binding protein and alkaline phosphatase with 10-folds and 100-folds increased sensitivities, respec-

while 100 CFU/100 mL of *E. coli* in inoculated river water. Such combination of phage-based diagnosis on paper fluidics offer new platforms to establish innovative detection techniques owing to sensitivity, robustness, and specificity and are personal friendly [47]. Additional improvement in the sensitivity of this method was reported by using fluorescent quantum dots (QDs) for phage labeling. QDs increased the stability and intensity of luminous signal and also enhanced the sensitivity of epifluorescence microscopy and flow cytometry-based detection platforms. The phage head was modified with biotin tagging peptide. The QDs coated with streptavidin were permitted to become bounded to biotinylated bacteriophages. By this approach, detection limit of for *E. coli* was only 20 CFU/

Similarly, on the basis of phage fluorescent-based detection assays, *Salmonella* in sea water was detected with the help of genetically modified bacteriophages P22 with assay time of 1 h and LOD of 10 CFU/mL [48], while TNT and TNB 1 ng/mL were detected in water with the help of phage display-selected scFv [49]. Likewise,

 CFU/g of *B. anthracis* in soil was detected with the help of Wβ phage involving fluorescence assay [50]. A magnetoelastic biosensor involving JRB7 phage as a bio-recognition element detected 104 spores/mL of *B. anthracis* in water [51], while impedimetric biosensor based on *S. arlettae* specific phage detected 200 CFU/mL of

Despite the abovementioned applications of phage-based biosensors, **Table 1** highlights some other representative applications of phage-based biosensors in detection of pathogenic bacteria, food safety, and environmental monitoring.

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 applications of reported promising platforms of phage-based sensors in the screening of food- and environment-related contaminants. We reviewed demonstrative phage/phage components applied in sensors' development for diagnosis of food pollutants specifically comprising pathogens and toxins. By collaboration with engineers and scientists from multidisciplinary area to design a field applicable sensor and make advancements in phage-based sensors for food safety and environmental monitoring, we expect that this chapter might bring together the technologies related to application of phage-based sensors, in food and environmental safety, and infectious disease

CFU/mL in broth

tively. The increased sensitivity enabled *E. coli* detection of 103

**184**

104

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

