Aseptic technique

Aseptic technique is the set of practices that prevent microorganisms from entering a sterile solution during handling. In research peptide work it comes down to a handful of habits: work on a clean surface, wash hands, swab every vial stopper with an alcohol pad and let it dry, use a new sterile needle and syringe for each draw, never touch the needle or the inside of a cap, and never leave a needle sitting in a stopper.

The reason it matters more for peptides than for many other reagents is the multi-dose vial. A reconstituted vial may be punctured twenty or thirty times over several weeks. Bacteriostatic water slows bacterial growth but does not sterilise, so each puncture is an opportunity for contamination that the preservative can only partly cover. A cloudy solution, particles, or an unexpected colour change after reconstitution are signs a vial should be discarded.

The reconstitution guide and the subcutaneous injection guide show the technique step by step. None of it is difficult; it only needs to be done every time.