Reconditioned microplates for Pierce BCA protein assay
This study utilised both new and reconditioned microplates for a Pierce™ BCA Protein Assay. Two 96-well microplates were contaminated with 0.5 mL of BSA (2 mg/mL), then reconditioned using our process. BSA standards were prepared according to the dilution schemes specified in the Pierce™ BCA Protein Assay Kit protocol (Thermo Fisher Scientific, Catalog Nos. 23225, 23227, and A65453), with concentrations ranging from 25 µg/mL to 2000 µg/mL.
Each sample was tested in duplicates across new and reconditioned microplates according to the kit protocol. For the assay, each BSA standard and water control were pipetted into designated wells. The plates were incubated for 2 hours at 37°C to ensure the detection of low protein concentrations. Standard curves were constructed for both new and reconditioned microplates, to compare and analyse their absorbance. The new microplate’s curve was also used to determine the concentrations of negative controls (water) on both new and reconditioned microplates and ensure they were similar.
This experiment allowed us to assess whether there were any residual proteins present in reconditioned microplates.
Results
Standard curves obtained from new and reconditioned microplates are equivalent (differences observed are within the range allowed by the kit). Additionally, wells filled with water in the reconditioned microplates showed no difference compared to the wells in the new microplate, indicating that they contained no residual proteins.
Similarly, the kit was used to analyse the protein presence in 1.5 mL conical tubes. No differences were found when compared to new tubes either.
Conclusion
Our process operated in a way that allows the use of reconditioned microplates and reconditioned tubes in precise protein quantification experiments.
Protein swabs
VERIFY® RESI-TEST™ Cleaning Indicators detect the absence or presence of protein and protein residues with a sensitivity of ≥ 1μg. The test is colorimetric : blue or dark green indicates a sample contaminated with proteins, and brown to light green indicates a sample with no protein contamination. Those tests are used to validate the control the efficacy of our cleaning process for every reconditioned consumables batch.
Before reconditioning
Consumables previously used for manipulating blood or cells test positive for proteins.
After reconditioning
At the end of our cleaning process, consumables are tested for protein presence before being packed. Exemples are shown here for consumables previously used with blood or cells.