How to increase DNA concentration?

You can increase DNA concentration by eluting DNA from multiple extractions into a single, reduced volume of elution buffer.

Increasing DNA concentration is often necessary for downstream molecular biology applications like PCR, sequencing, or cloning, which require a minimum amount of DNA in a specific volume. One effective strategy involves manipulating the elution step during DNA extraction.

Method Based on Reference

Based on the provided reference, a practical way to boost DNA concentration is by combining the DNA yield from two separate extractions into a smaller final volume. This method leverages the ability to elute DNA from a purification matrix (like a column or magnetic beads) using a minimal volume of buffer.

Here's how the technique works, as described in the reference:

1. Perform Two Extractions: Complete two separate DNA extraction procedures from your starting material (e.g., tissue, blood, cells) following your standard protocol up to the final elution stage.
2. First Elution with Reduced Volume: When you reach the elution step for the first DNA extraction tube/column, add a smaller than usual volume of elution buffer (for example, 50 µL as mentioned in the reference).
3. Elute First Sample: Allow the DNA to rehydrate and dissolve by incubating with the buffer, then centrifuge the first tube/column according to the protocol to collect the eluate (the liquid containing the dissolved DNA).
4. Transfer Eluate: Carefully collect the entire volume of the eluate from the first tube.
5. Use Eluate as Elution Buffer for Second Sample: Transfer this collected eluate (the 50 µL containing DNA from the first extraction) into the second extraction tube/column, where the DNA from your second extraction is still bound to the matrix.
6. Elute Second Sample: Use this transferred 50 µL of buffer (which now contains DNA from the first sample) to elute the DNA from the second tube/column by incubating and centrifuging again.

Expected Result

By performing these steps, you effectively combine the DNA yield from both separate extractions into the final 50 µL eluate. This results in a higher DNA concentration in that final volume compared to eluting each sample separately with 50 µL or a larger standard volume.

The reference indicates that this technique can increase the final DNA concentration by approximately 50% to 70%.

Summary Table: Combining Elutions

Step	Action	Result
Initial Extraction	Process two samples separately up to the elution step.	DNA is bound to purification matrix in two tubes/columns.
First Elution	Add reduced elution buffer (e.g., 50 µL) to Tube 1. Elute.	Eluate contains DNA from Sample 1 in 50 µL.
Transfer	Transfer the 50 µL eluate from Tube 1 to Tube 2.	Tube 2 now contains DNA from Sample 2 bound to matrix, plus 50 µL buffer containing DNA from Sample 1.
Second Elution	Use the transferred 50 µL buffer to elute DNA from Tube 2.	Final eluate (50 µL) contains combined DNA from Sample 1 and Sample 2.
Outcome	Final DNA concentration significantly increased in the 50 µL volume.	50% to 70% increase possible (based on reference).

This approach is particularly useful when working with limited starting material or when high DNA yield is challenging to obtain from a single extraction.