General Cleaning Guidelines
It is essential to maintain the Langendorff system in a clean condition as the physiological perfusate
solutions support bacterial and fungal growth which can affect the heart preparation. Daily and
fortnightly cleaning protocols are described below. Adequate maintenance will prolong the life of your
Use a germicide
To minimize the growth of algae and microorganisms in the waterbath and tubing of the heating system,
always use deionized (or distilled) water. A cationic surfactant and germicide can be used to keep the
water bath free of bacterial and algal growth. ‘Sigmaclean’ water bath treatment (Product Number
S5525, CAS Number: 68424-85-1), from Sigma, used at a dose of 0.16 mL/L or 0.02 oz/gal., is
This should keep the heating system clean between the fortnightly cleaning protocol, however,
if slight turbidity in the waterbath is observed, then drain and refill the waterbath with dilute domestic
bleach (sodium hypochlorite solution) — use about 25 mL of 4% bleach per liter of water. Allow to stand
for about 10 minutes, then drain and rinse with deionized water, and then refill with fresh deionized
water containing the germicide.
Do not autoclave
Note that the Langendorff apparatus is mainly constructed of Perspex (or acrylic). Under no circumstances
should the system be autoclaved.
Do not use boiling water
Boiling water may soften and distort the Perspex of the Langendorff apparatus. Do not use water hotter
than 80 °C when cleaning the system.
Do not use organic solvents
Do not use alcohol, or other organic solvent based cleaning agents, as these can damage the Perspex
Do not use abrasives
Avoid the use of all abrasive pastes and scourers such as steel wool. These will damage the Perspex
surfaces and perfusate reservoirs and make future cleaning more difficult.
Do not use aggressive chemicals
Aggressive chemicals, such as concentrated hydrochloric acid, sulfuric acid and sodium hydroxide can
damage the system and should never be used.
Langendorff For Internal Use Only 7 ADInstruments Primer Document For Internal Use Only
Daily cleaning protocol
After daily use the perfusion system, junction block and heart chamber should be cleaned (the waterbath
need not be emptied to do this):
1. Keep a slow gas stream passing through the bubblers to prevent solution from entering the gas
2. Remove all perfusate solution from the system and flush the perfusate reservoirs and connection
tubes with deionized water. If necessary, flush with hot (65–80 °C) water, to dislodge any biological
material. Higher temperatures may damage the surface of the Perspex reservoirs.
3. Fill the perfusion system with 1 mol/L ascorbic acid solution and leave in the system overnight.
4. Next morning, remove the ascorbic acid solution (the ascorbic acid may be used 6-8 times) then purge
the system thoroughly with deionized (or distilled) water.
5. Refill the reservoirs with perfusate solution for the new experiment.
Fortnightly cleaning protocol
This protocol should be followed every two weeks, or before long term storage.
Perfusate reservoirs and waterbath
Clean as follows:
1. Before cleaning, all connection tubing should be disassembled, and the waterbath and perfusate
reservoirs should be emptied. Ensure that the bubbling regulators for each perfusate reservoir have
2. Use a soft nylon brush and a mild detergent solution (non-foaming, if possible) to clean inside
the perfusate reservoirs, waterbath, junction block and heart chamber. Drain and then rinse with
3. If there are still persistent algal stains, fill the reservoirs and waterbath with diluted household bleach
(sodium hypochlorite solution). Use about 25 mL of 4% bleach solution in about 1 L of water. Allow
to stand for 10 minutes. Drain and flush with large quantities of tap water. Repeat step 2.
4. Check that the bubbling system still works.
5. If the system is to be stored, allow all parts to dry thoroughly.
Heart chamber and Junction Block
In cases of severe soiling, disconnect the glass heart chamber or junction block from the system and
immerse it in full strength domestic bleach solution (4% available chlorine) and leave overnight. After a
thorough cleaning with detergent solution, tap water and deionized water, reconnect the heart chamber
to the system. Never use full strength bleach to clean tubing or Perspex surfaces.