Handling and laboratory practice

Research material is supplied non-sterile, with no endotoxin limit and no assurance of what is on the outside of the vial. Handling practice exists to protect two things: the person doing the work, and the integrity of the material.

Before you start

Assess the hazard first. In the UK that is a COSHH assessment, and it is a legal requirement for work with substances hazardous to health, not a formality. For most lyophilised peptides the significant routes are inhalation of powder and contact with eyes and skin; the fine, static-prone nature of freeze-dried material makes the first easier than people expect.

Where a safety data sheet exists, read it before opening anything. Where one does not, treat the material as an uncharacterised biologically active substance, because that is what it is.

Work area

• Clear the bench and wipe down with 70% ethanol. Let it dry — contact time is what does the work, and a wet surface is not a disinfected one.
• Assemble everything you need before you open a vial. Reaching across an open work area with contaminated gloves undoes the preparation.
• Work away from draughts, open windows and air conditioning outlets. Air movement carries both powder and contamination.
• Handle powder in a fume hood or a suitable enclosure where the assessment calls for it.

Personal protection

Nitrile gloves, safety glasses and a lab coat as a baseline. Gloves protect the material from you as much as the reverse: skin carries proteases and salts, and a fingerprint on a stopper is a contamination route.

Change gloves between compounds. Cross-contamination between vials is invisible and invalidates everything downstream.

Aseptic transfer

1. Swab the stopper with 70% ethanol and let it dry before piercing it.
2. Use a fresh sterile needle and syringe for every transfer. Consumables are cheaper than a repeat.
3. Pierce the stopper once, cleanly, near the centre. Repeated piercing sheds rubber particles into the vial.
4. Keep the vial upright while the seal is compromised.
5. Do not touch the needle to anything but the stopper — not the outside of the vial, not the bench, not a gloved finger.
6. Reseal and refrigerate promptly once the transfer is done.

Sterile technique does not make non-sterile material sterile. It stops you making it worse.

Labelling

Every vessel gets a label at the moment it is filled, carrying the compound, the lot number, the concentration, the diluent and the date. Use a solvent-resistant marker or a cryogenic label: ordinary adhesive fails at freezer temperatures and ordinary ink lifts off under ethanol, which is how unidentifiable tubes accumulate at the back of a freezer.

Keep the lot number on every derived aliquot, not just the parent vial. It is the only link back to the certificate of analysis, and it is unrecoverable once the original packaging is gone.

Spills

For dry powder, do not brush or blow it — that aerosolises it. Dampen with a suitable solvent, wipe inwards from the edge of the spill, and dispose of the wipes as contaminated waste. For solutions, absorb, then clean the area.

Disposal

• Needles and glass to a sharps container, without recapping.
• Contaminated consumables as laboratory waste under your local arrangements.
• Unused material through a licensed waste route. Not down a drain, and not in general refuse.
• Empty vials still hold residue — treat them as contaminated.

Disposal is a legal obligation on the holder of the waste, and it is the step most often improvised. Confirm the route before ordering, not after.