Non-specific nucleases from the genus Pseudomonas for use in facilitating flow of cells through a microfluidic channel

A method of preparing a cell suspension, comprising:

• (a) obtaining a recombinant nuclease, and
• (b) incubating the cell suspension with the recombinant nuclease until nucleic acids present in the suspension and/or released from cells are removed, thereby facilitating flow of the cells through a microfluidic channel;
• wherein the recombinant nuclease contains an amino acid sequence that is at least 90% identical to the amino acid sequence set forth in SEQ ID NO:2, and
• wherein the recombinant nuclease when present in a solution at 4° C. has non-specific nuclease (NSN) activity with a kcat value of at least 100 s−1.

A method of preparing a cell suspension, comprising:

• (a) obtaining a recombinant nuclease, and
• (b) incubating the cell suspension with the recombinant nuclease until nucleic acids present in the suspension and/or released from cells are removed, thereby facilitating flow of the cells through a microfluidic channel;
• wherein the recombinant nuclease contains an amino acid sequence that is at least 90% identical to the amino acid sequence set forth in SEQ ID NO:2;
• wherein the recombinant nuclease when present in a solution at 4° C. has non-specific nuclease (NSN) activity with a kcat value of at least 10 s−1;
• and
• wherein the method further comprises complexing cations that are present in the cell suspension before or during step (b).

A kit for facilitating flow of cells in a suspension through a microfluidic channel and/or to prepare cells in a suspension for cell sorting, wherein the kit comprises:

• (i) a reagent solution that comprises a recombinant nuclease and a non-naturally occurring cation complexing agent,
• wherein the nuclease comprises an amino acid sequence that is at least 90% identical to the amino acid sequence set forth in SEQ ID NO:2,
• wherein the nuclease has non-specific nuclease (NSN) activity in the reagent solution at 4° C. has a kcat value of at least 100 s−1, and
• (ii) instructions for using the solution for removing nucleic acids from the cell suspension to facilitate flow of the cells through the microfluidic channel;
• wherein the amount and concentration of the recombinant nuclease in the solution is effective for degrading and removing nucleic acids from the cell suspension when combined and incubated at a temperature between 0° C. and 10° C.