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Bacteriophages are the most abundant biological entity in the world and hold a tremendous amount of unexplored genetic information. Since their discovery, phages have drawn a great deal of attention from researchers despite their small size. The development of advanced strategies to modify their genomes and produce engineered phages with desired traits has opened new avenues for their applications. This review presents advanced strategies for developing engineered phages and their potential antibacterial applications in phage therapy, disruption of biofilm, delivery of antimicrobials, use of endolysin as an antibacterial agent, and altering the phage host range. Similarly, engineered phages find applications in eukaryotes as a shuttle for delivering genes and drugs to the targeted cells, and are used in the development of vaccines and facilitating tissue engineering. The use of phage display-based specific peptides for vaccine development, diagnostic tools, and targeted drug delivery is also discussed in this review. The engineered phage-mediated industrial food processing and biocontrol, advanced wastewater treatment, phage-based nano-medicines, and their use as a bio-recognition element for the detection of bacterial pathogens are also part of this review. The genetic engineering approaches hold great potential to accelerate translational phages and research. Overall, this review provides a deep understanding of the ingenious knowledge of phage engineering to move them beyond their innate ability for potential applications., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Inc.)

The development of a novel colorimetric method is reported, using vB_YepM_ZN18 phages along with AuPt nanozyme for the sensitive detection of Y. pseudotuberculosis. The phage used in this work has been extracted from hospital sewer water and is highly specific toward Y. pseudotuberculosis. The synthesized AuPt NPs possess peroxidase-like activity, which is suitable in the development of nanozyme based detection system. Furthermore, phages@MB and AuPt@phages are added into the bacterial samples for co-incubation, forming an intercalated complex. The magnetic separation and absorbance analysis of enzymatic reaction are carried out for the detection of targeted bacteria. The proposed method has a limit of detection of 14 CFU/mL, a wide linear range from 2.50 × 10 1  ~ 2.50 × 10 7  CFU/mL and the assay completion time is 40 min. Benefitting from the outperformance of this sensor, we have successfully employed the developed sensing platform for the detection of Y. pseudotuberculosis in food industry and hospital specimens., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Some bacterial species are deadly disease-causing pathogens with high morbidity and mortality in humans worldwide. Key interfaces in the transmission of bacterial pathogens include food, water, dairy products, peridomestic animals, and human interplay. Early-stage detection of such bacteria is crucial in minimizing the risk of bacterial diseases and ensuring early diagnosis. Majority of the conventional microbiological and biochemical detection methods are laborious, require skilled individuals, and are not always accurate. Various molecular diagnostic tools and assays, utilizing sensitive and specific biorecognition elements, such as enzymes, antibodies, and nucleic acids, have been developed and widely used for the detection of pathogenic bacteria. An ideal biorecognition element for the detection of pathogens should be highly specific, stable, sensitive, selective, rapid, easily available, and cost-effective. Bacteriophages, which meet such prerequisites, may be used as biorecognition element alternatives to the currently available molecular probes in the development of cost-effective, specific, quick, sensitive, and reliable platforms (sensors and assays) for the detection of bacterial pathogens. This review details bacteriophage biology and various recognition sites and receptor-binding proteins on the surfaces of tailed phages, which can be used as the recognition sites for specific bacterial detection. It highlights structures and receptors on the surface of bacteria for binding and attachment of specific phages. These features of bacteria and phages provide a basis for establishing methodologies for phage-based bacterial detection, including phage-induced bacterial lysis, phages immobilized on a transducer surface, fluorescently labelled phages, phage-conjugated quantum dots, and recombinant reporter phages, particularly monitored through optical and electrochemical transducer systems., (Copyright © 2021 Elsevier B.V. All rights reserved.)

In nature, different types of bacteria including pathogenic and beneficial ones exist in different habitats including environment, plants, animals, and humans. Among these, the pathogenic bacteria should be detected at earlier stages of infection; however, the conventional bacterial detection procedures are complex and time-consuming. In contrast, the advanced molecular approaches such as polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) have significantly reduced the detection time; nevertheless, such approaches are not acceptable to a large extent and are mostly laborious and expensive. Therefore, the development of fast, inexpensive, sensitive, and specific approaches for pathogen detection is essential for different applications in food industry, clinical diagnosis, biological defense and counter-terrorism. To this end, the novel sensing approaches involving bacteriophages as recognition elements are receiving immense consideration owing to their high degree of specificity, accuracy, and reduced assay times. Besides, the phages are easily produced and are tolerant to extreme pH, temperature, and organic solvents as compared to antibodies. To date, several phage-based assays and sensors have been developed involving different systems such as quartz crystal microbalance, magnetoelastic platform, surface plasmon resonance, and electrochemical methods. This review highlights different taxonomic species and genera of phages infecting eight common disease-causing bacterial genera. It further overviews the most recent advancements in phage-based sensing assays and sensors. Likewise, it elaborates various whole-phage and phage components-based assays. Overall, this review emphasizes the importance of electrochemical biosensors as simple, reliable, cost-effective, and accurate tools for bacterial detection., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Yersinia pseudotuberculosis is an enteric bacterium causing yersiniosis in humans. The existing Yersinia pseudotuberculosis detection methods are time-consuming, requiring a sample pretreatment step, and are unable to discriminate live/dead cells. The current work reports a phage-based electrochemical biosensor for rapid and specific detection of Yersinia pseudotuberculosis. The conductive poly(indole-5-carboxylic acid), reduced graphene oxide, and gold nanoparticles are applied for surface modification of the electrode. They possess ultra-high redox stability and retain 97.7% of current response after performing 50 consecutive cycles of cyclic voltammetry.The specific bacteriophages vB_YepM_ZN18 we isolated from hospital sewage water were immobilized on modified electrodes by Au-NH2 bond between gold nanoparticles and phages. The biosensor fabricated with nanomaterials and phages were utilized to detect Yersinia pseudotuberculosis successfully with detection range of 5.30 × 102 to 1.05 × 107 CFU mL−1, detection limit of 3 CFU mL−1, and assay time of 35 min. Moreover, the biosensor can specifically detect live Yersinia pseudotuberculosis without responding to phage-non-host bacteria and dead Yersinia pseudotuberculosis cells. These results suggest that the proposed biosensor is a promising tool for the rapid and selective detection of Yersinia pseudotuberculosis in food, water, and clinical samples. [ABSTRACT FROM AUTHOR]

Due to the highly efficient and specific catalysis, enzymes have been extensively applied in various fields. In the development of enzyme-based sensing devices, the immobilization of enzyme is critical for achieving superior performance which is drastically dependent on enzyme stability and activity. In this study, we construct and assemble the beta-galactosidase(β -gal)-Soc fusion proteins onto biologically produced nanoparticle – T4 phage in vitro as a specific sensing probe for the rapid colorimetric detection of Escherichia coli K12. The stability and substrate affinity of β -gal assembled on T4 phage were largely enhanced in comparison with that of free β -gal due to this affinity-based immobilization, and the assay based on this β -gal T4 phage was able to quantify bacteria at concentration of 103 cfu mL−1 in drink water within 2 h. This affinity binding based enzyme immobilization strategy employed T4 bacteriophage capsid as the supporting nanoparticle and exhibited enhanced enzyme activity and stability which are highly favored for the future development of sensing applications. [Display omitted] • Bacteriophage T4 with assembled β -gal-Soc fusion protein on its capsid was designed and developed for bacteria detection. • The stability and substrate affinity of the β -gal T4 phage were significantly enhanced in comparison with that of free β -gal. • The detection system we developed can efficiently and specially capture E. coli K12 from complex background. [ABSTRACT FROM AUTHOR]

The routinely used enzymes, antibodies, and nucleic acids-based biosensors for detection of Staphylococcus aureus are often overwhelmed by limited selectivity, sensitivity, high cost, and inability to discriminate between live/dead cells. This necessitates the development of an ultra-sensitive, stable, and selective electrochemical biosensor capable of discriminating live S. aureus in a mixture of live/dead cells in food samples. The current study reports the development of an electrochemical biosensor through the immobilization of bacteriophage in surface-modified bacterial cellulose (BC) matrix. BC being highly porous and fibrous, offers a high surface area for the impregnation of carboxylated multiwalled carbon nanotubes (c-MWCNTs) and allows high-density phage immobilization. Surface modification of BC/c-MWCNTs with polyethyleneimine (PEI) provides a positive charge that facilitates oriented phage immobilization. FE-SEM and FT-IR analyses confirmed the development of BC/c-MWCNTs-PEI-phage bio-interface. Confocal microscopy analysis showed 11.7 ± 1.2 phage particles⋅μm-2 immobilized in the BC matrix and showed anti-staphylococcal activity by producing clear lytic zone and reduced bacterial growth. Differential pulse voltammetry (DPV) analysis detected 3 CFU⋅mL-1 and 5 CFU⋅mL-1 of S. aureus in phosphate buffer saline (PBS) and milk, respectively, within 30 min at neutral pH and showed stability over 6-weeks at 4 °C. The biosensor showed high specificity for S. aureus , both in pure and mixed cultures of non-host bacteria, and effectively discriminated live S. aureus in a mixture of live/dead cells. The developed biosensor represents a simple, sensitive, specific, and accurate tool for early detection of S. aureus in food samples. • Modified bacterial cellulose matrix supported the immobilization of up to 11.7 ± 1.2 phage particles/μm2. • First report of BC/phage-based electrochemical biosensor that can discriminate live S. aureus in a mixture of live/dead cells. • The developed ultra-sensitive biosensor detected 3 CFU/mL and 5 CFU/mL in PBS and milk, respectively in only 0.5 h. [ABSTRACT FROM AUTHOR]