# Simple, rapid, and efficient purification of M13 phages: The Faj-elek method

## TL;DR

A new method called Faj-elek is introduced for purifying M13 phages more efficiently and inexpensively than traditional methods.

## Contribution

The Faj-elek method uses syringe filters and pH changes to purify M13 phages with higher recovery rates than PEG precipitation.

## Key findings

- The Faj-elek method achieved a 250% higher recovery rate compared to the standard PEG method.
- Phages purified using this method retained their infectivity and were easier to recover using TBS buffer.

## Abstract

M13 bacteriophages (phages) are used as very important tools in molecular biology, biotechnology and, nanotechnology. Many methods have been developed so far for the purification of these phages. However, it is important that phages retain their infecting properties, especially in biotechnological applications such as phage display technology. The most widely used is the PEG precipitation method, but it has some limitations such as impurities and reduced infectivity. To overcome them, we developed a new method for purification of M13 bacteriophages using syringe filters made of cellulose acetate membranes with a pore diameter of 0.22 µm. Phages were aggregated so that they could remain on the filters and for this purpose, the pH of the phage cultures was reduced to 3. The phage cultures were filtered and then the phages were recovered in tris-buffered saline (TBS) buffer (pH 10.5) by reversing the filter. The recovery rate was 250% higher than the standard PEG method. This new Faj-elek method offers an alternative to existing methods, allowing cheaper, easier and faster purification of M13 phages using syringe filters available in every research laboratory.