Sterile Handling Procedures in Research Environments
Minimizing contamination risk during peptide preparation and handling.
Contamination introduces variables that cannot be controlled for after the fact. Whether you're running cell-based assays or in vivo models, sterile technique is non-negotiable for reproducible, publishable data.
Personal Protective Equipment
At minimum, wear nitrile gloves throughout all handling. Change gloves after touching non-sterile surfaces, handling vials from storage, or sneezing and coughing near the work area. For aerosol-generating procedures, add a surgical mask.
Avoid touching your face, phone, or other surfaces without changing gloves. A single touch of the forehead can deposit enough skin flora to contaminate a cell culture preparation.
Working Environment Preparation
Wipe all surfaces with 70% isopropanol (IPA) or 70% ethanol at least 15 minutes before beginning work — this gives the alcohol time to evaporate and for any residual contamination to be eliminated. Include the inside walls, work surface, and any equipment that will be placed inside the hood.
- UV decontamination of biosafety cabinets: 30 minutes before use where available
- Surface wipe with 70% ethanol: minimum 15 minutes before use
- Pipette tips, tubes, and syringes: use sterile, individually packaged items
- Reused glassware: autoclave at 121°C for 15 minutes before use
Needle and Syringe Technique
When drawing up reconstituted peptide, use a fresh sterile syringe and needle for each operation. Do not touch the needle to any non-sterile surface after removing from packaging. Insert through a sterile rubber septum or use a new vial for each draw.
Flaming needles is not sterile technique — it introduces combustion residue and is a fire hazard. Use only sterile, single-use needles.
Sterility Testing Considerations
For experiments requiring confirmed sterility (in vivo research with sterility requirements, long-duration cell culture studies), consider filtering reconstituted solutions through a 0.22 µm syringe filter. This removes bacteria and most fungal spores but does not address viral contamination.
Note that some peptides may bind to syringe filters — particularly hydrophobic sequences. Pre-wet filters with your solvent and discard the first 0.5–1 mL passing through to reduce binding losses.
Documentation and Traceability
Every preparation should be documented in a lab notebook or electronic record: date, operator, compound, lot number, concentration, solvent, volume prepared, sterility measures taken, and storage location. This documentation allows you to trace any anomalous results back to the preparation step.