Thermal and pH Stability Testing

Creative Biolabs is a leading service provider that focuses on phage therapy. Based on our extensive experience and advanced platforms, now we can provide novel phage thermal and pH stability test services for our clients all over the world.

Factors Affecting Phage Efficiency

Antimicrobial resistance has been one of the most serious medical problems worldwide and phage therapy has been the most promising alternative to the antibiotic. Studies have shown that factors such as temperature and pH are important for phage survival. pH can affect phage attachment, infectivity, intracellular replication, and proliferation. In general, bacteriophages have the highest infectivity ranging from pH 5.0 to pH 10.0. In this case, neither human pH nor neutral pH storage conditions affect phage infection efficiency. What’s more, temperature is also an important factor that influences the infectivity of phages. Studies showed that phages present maximum stability in the temperature range of 25-37°C. Most phages are stable up to 50°C, so temperature also affects phage efficiency.

Phage Thermal and pH Stability Test

The thermal stability of phages can be detected by pre-incubating phage suspensions at various temperatures at pH 7.0 for 2 hours. Surviving phage can be titered by the double agar layer method after cooling the phage suspension in ice water. In this experiment, phage lysates were diluted in tryptic soy broth (TSB) to an initial concentration of ∼10⁷ PFU/ml. The relative temperature stability of the phages was then determined at a series of different temperatures (-20, 4, 22, and 37°C), each of which included a control without phage. Each phage was tested 3 times to ensure the accuracy of the experimental data.

The pH stability of phage can be detected by pre-incubating phage suspensions at different pH levels for 2 or 24 h at 25°C. Surviving phages can be immediately counted by the double-agar layer method. In this experiment, phage lysates were diluted in tryptic soy broth (TSB) to an initial concentration of ∼10⁸ PFU/ml. The relative pH stability of the phages was then determined at a series of different pH (pH 4.0, 6.0, 8.0, and 10.0), each of which included a control without phage. Each phage was tested 3 times to ensure the accuracy of the experimental data.

Fig.1 pH and thermal stability.¹

Creative Biolabs offers the most advanced and comprehensive assays for phage thermal and pH stability determination. We work to amplify your success in a highly collaborative manner. If you are interested in our services, please do not hesitate to contact us for detailed information.

Reference:

1. Wannasrichan, Wichanan, et al. "Phage-resistant Pseudomonas aeruginosa against a novel lytic phage JJ01 exhibits hypersensitivity to colistin and reduces biofilm production." Frontiers in Microbiology 13 (2022): 1004733. Under Open Access license CC BY 4.0. The image was modified by extracting and using only Part E,F of the original image.