Post-Experiment Equipment Cleaning
After experiments, thoroughly clean all equipment. The nutrient solutions used for isolated organ or tissue preparations create an ideal environment for bacterial and fungal growth. Standard cleaning procedures depend on:
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Chemicals and Biological Materials: The types of substances used in experimental protocols.
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Measurement Interference: The measurements made and potential interference from cleaning substances.
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Usage Frequency: How often the equipment is used and the number of operators.
Cleaning Agents and Procedures
Soaps: Non-phosphate soaps are preferred. Insoluble phosphates can form with calcium and magnesium from physiological salt solutions. Be aware that bactericidal soaps might contain iodine or other materials that can affect isolated tissues and cells, so thorough rinsing is critical after use.
Accessories: Cleaning supplies like brushes should be dedicated to a single piece of equipment to prevent cross-contamination.
Maintenance Protocol: To properly maintain equipment, consider implementing the following:
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Assign one individual responsibility for maintenance.
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Post clear, written cleaning protocols with the equipment.
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Maintain a logbook to record cleaning dates, problems, and suggestions.
Water Circulator: This is often overlooked as a source of contamination. Keep it clean, rinse the bath, and regularly change the solution to prevent precipitate buildup. Add a small amount of liquid bleach or copper sulfate to the distilled, deionized water in the circulator to prevent bacterial or fungal growth.
Storage: If equipment won't be used regularly or is being stored, clean, rinse, and dry it thoroughly beforehand to reduce airborne contamination from microbes and spores. If equipment hasn't been used for some time, clean and rinse it properly before any experiments. If you experience two consecutive experimental failures with a previously reliable protocol that can't be explained by obvious sample damage, poor dissection, or solution issues, contamination may be the cause, and thorough cleaning is recommended.
Cleaning Radnoti Glassware
Radnoti apparatus is made of borosilicate glass and can be cleaned with various soaps, ethyl alcohol, or dilute acids (0.1 M HCl or HNO3).
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Rinsing: After using any cleaning agents, thoroughly rinse all components multiple times with distilled, deionized water to remove all traces of cleaning agents and salts.
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Large Glassware: Large glassware like reservoirs or assemblies can be flushed while in the system, but ensure aerators, stopcocks, and associated parts are thoroughly cleaned.
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Aerators: Carefully blow aerators dry with gas or air after the final water rinse. If using acid for cleaning, test the runoff water's pH to ensure the acid has been completely removed.
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Protective Gear: Always use proper protective gear and training when handling chemicals to minimize personnel hazards and contamination.
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Avoid: Heated acid or chromic acid is not recommended due to potential hazards and heavy metal contamination. Water or gas under high pressure can damage glassware and cause injury. High concentrations of acids, or especially alkalis, can destroy glass frit filaments and are not recommended.
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Lipophilic Substances: If very lipophilic substances (e.g., prostaglandins, ionophores, certain dyes) were used, rinse with ethyl alcohol or the most appropriate organic solvents first, followed by thorough water rinsing.
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Toxins/Biohazards/Radiochemicals: These substances require specific cleaning apparatus and a dedicated containment area to reduce risks.
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Bleach: Diluted bleach can be used on glassware but must be thoroughly rinsed.
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Blocked Aerators: Glass aerators can be cleaned with water or dilute acid if blocked. A general soap and water rinse to remove soluble materials, followed by cleaning with 0.1M HCl or 0.1 M HNO3 for several hours or overnight and multiple water rinses, usually removes most contaminants. If this fails, 1 M acid can be used for a shorter period.
Sterilization
Glassware can be sterilized. However, remove any plastic fixtures (aerators, stopcock caps, etc.) before sterilization.
Cleaning Non-Glass Items
Initially clean non-glass items, including water jacket tubing, with aqueous soap solutions. Non-phosphate soaps are preferred.
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Chemical Resistance: Consult a material data sheet to ensure cleaning or sterilization agents won't damage the material.
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Key Areas: Pay special attention to cleaning the aerator, tubing, syringe ports, cannulae, pressure transducer fittings, septa, balloons, other catheters, and electrodes (oxygen, pacing, ion selective, etc.).
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Tubing Inspection: Inspect tubing at the pump head for wear. The interior can roughen over time, creating sites for bacterial growth. Use high-grade tubing with low plasticizer leaching. Silicone tubing is permeable to gases, so generally avoid it for transporting gassed solutions.
Water Circulator Specifics (Radnoti Thermal Circulator)
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Water Quality: Use distilled or deionized water with a resistivity greater than 10 MΩ in the Radnoti Thermal Circulator to prevent corrosion and reduce precipitate buildup. Double-distilled water is not recommended.
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Fluid Inspection: Periodically inspect and replace the reservoir fluid.
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Cleaning: Routinely clean the stainless steel tank by sponging with tap water and dishwashing detergent, followed by thorough rinsing. Ensure the fluid is at a safe handling temperature before changing.
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Algae Control: To restrict algae growth, the manufacturer recommends opaque circulation lines and using chloramine-T at a concentration of 1 gram per 3.5 liters.
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Water-Jacketed Tubing: If you notice considerable dirt or algae buildup in the water-jacketed tubing, consider replacing it. Contact sales representatives for new tubing.
For further technical assistance with this or any other issue, please contact ADInstruments Technical Support by clicking HERE.