Tips for DSC Cell Cleaning

The basic concept for cell cleaning is the same as ITC. The choice of cleaning solution, cleaning frequency, and soaking temperature determine the effectiveness of the cleaning.

Applications often use biological macromolecules like proteins, and the choice of cleaning solution is often made from the perspective of how to decompose proteins.

Below are specific cleaning methods.

＜Important Precautions Before Operation＞

・The cleaning solution is strong alkaline and harmful. Be sure to wear appropriate protective gear during operation.

・Long soaking involves risks such as solution drying, precipitation, and dirt adherence due to forgetting to rinse.

・In the worst case, there is a risk of causing irreversible damage to the cell. Please perform the operation under your own responsibility.

・Depending on the degree of dirt, replace the solution with a limit of up to about one hour. Do not leave it overnight.

＜Items to Use＞

・Cleaning solution

・Gas-tight syringe (if using VP-Capillary DSC Manual, VP-DSC)

・Included micropipette (if using PEAQ-DSC Manual)

・Cleaning Device (if using VP-Capillary DSC Manual, VP-DSC. A cleaning tool that allows liquid delivery into the sample cell with ThermoVac included in the instrument)

・Cleaning Tool (cleaning tool included with PEAQ-DSC Manual)

・ThermoVac or Aspirator

＜Regarding the Cleaning Solution and Conditions＞

・14% DECON90 aqueous solution (effective for proteins and other dirt, recommended cleaning solution for regular maintenance. Maximum soaking temperature 60°C, do not exceed 1 hour)

・Cleaning solution (a mixed solution of sodium hypochlorite and sodium hydroxide, particularly effective in dissolving proteins and removing dirt firmly adhered to the cell)

　　＜Preparation of the Cleaning Solution＞

　　　※Wear gloves and protective goggles.

　　　1) Dissolve 5 grams of sodium hydroxide in about 25 mL of ultrapure water.

　　　2) Add 50 mL of sodium hypochlorite solution (10-15% chlorine) to 1).

　　　3) Make up to 100 mL with ultrapure water and mix well.

　　＜Storage Method of the Cleaning Solution＞

　　　The cleaning solution will be effective for at least one year if stored in a sealed container in a dark place.

　　　If precipitation is observed, please discard and prepare again, even within the storage period.

・1% Zymit (a cleaning solution with protein-degrading enzymes. Purchase the stock solution and dilute to the manufacturer-specified concentration. Maximum soaking temperature 25°C, do not exceed 12 hours)

＜Cleaning Operation＞

1) Attach the plug to the pressure sensor.

2) Remove ultrapure water from both Sample/Reference cells.

3) Use a gas-tight syringe or micropipette to fill both cells with the cleaning solution (do so in the same manner as filling the cell with a sample).

4) Once the cleaning solution has been poured into both cells, discard all of it.

5) Fill both cells again with the cleaning solution (remove any excess cleaning solution that overflows as much as possible. It’s the same manner as when filling with a sample).

6) Set the cell temperature to the target temperature.

7) Cover the cell port with a paper towel or similar to prevent debris from entering the cell.

8) Soak for 10 minutes to a maximum of 1 hour, depending on the degree of dirt.

9) After soaking is complete, return the cell temperature to 25°C (note: inserting the gas-tight syringe while the cleaning solution is warm may damage the syringe or cause the contents to spill out from the cell).

10) Carefully withdraw the cleaning solution, which has returned to room temperature, using a gas-tight syringe, and then rinse the gas-tight syringe with sufficient ultrapure water immediately.

11) Use the gas-tight syringe to fill both cells with ultrapure water and slowly perform pumping actions. Rinse the entire cell by moving up and down several times.

12) Rinse each of the Sample/Reference cells with a total of 50-100 mL of ultrapure water. For the Sample cell, cleaning with the Cleaning Device is convenient.

13) If cleaning solution adheres to the cell port area, wipe it off with a lab wipe moistened with ultrapure water.

14) When inserting the needle portion of the gas-tight syringe into the cell, do so slowly. Striking the cell bottom with the metal tip can scratch the cell surface, causing noise or failure in the worst case. The amount injected during rinsing should not overflow from the cell port.

15) After rinsing is complete, fill both cells with ultrapure water.

＜Precautions During Cleaning Operation＞

・Please rinse both cells thoroughly with ultrapure water. Using ThermoVac/Cleaning Device is also effective.