Transform Your Protein Quantification

Get reproducible, quantitative data throughout product development, with as little as 5 µL of sample.

Protein Quantification Upscaled

Different samples containing protein (hIgG), non-protein (ETFE), and mixed components with ThT Fluorescent excitation (Aura FL Channel 1) and non-fluorescent Side Illumination Membrane Imaging (SIMI).
Counting hIgG protein aggregates, volumetrically.

Why Use Aura for Protein Quantification Analysis?

The Aura family of instruments can overcome the limitations experienced with more traditional protein quantification methods. These five methods all have disadvantages:
  • Bradford/Coomasie Blue Test—where negative Coomasie blue stains bind positively charged proteins. While fast and simple, it cannot detect protein aggregates as aggregates often have altered structures and may not bind the dye in the same way as soluble proteins and is not compatible with SDS or Triton X-100 detergents
  • Lowry Test—Formation of Cu-N complexes, then tyrosine and tryptophan react with Folin-Ciocalteau reagent, producing a blue-green color. The test is sensitive and accurate but is not compatible with common reagents such as Tris, EDTA, DDT, 2-mercaptoethanol, and carbohydrates
  • BCA—Bicinchoninic acid test where absorbance is proportional to protein concentration. Sensitive and recommended for samples containing detergents/denaturing agents, but samples containing ammonia, EDTA, reducing sugars, or lipids may interfere with the assay, and colors are not stable
  • Biuret—based on the formation of a colored complex between Cu2+ and NH groups of peptide bonds. While fast, it is insensitive and requires 2 to 4 mg of proteins for testing
  • UV absorption—measuring absorption of tryptophan and tyrosine at 280 nm, estimates the amount of protein quickly. However, it is not compatible with protein extractions that use detergents/denaturing agents and is not specific to proteins
  • Clearly, better methods of protein quantification are needed when looking for aggregates or insoluble protein - Aura+ and Aura PTx instruments are more accurate, rapid, sensitive, and versatile, meeting the increased demands of today’s research and development of biological therapies

Optimized Biopharmaceutical Lot Release

Improve Your Detection

Accurate protein quantification is essential to developing an effective, safe biotherapeutic that meets USP guidelines and federal regulations. To arrive at a reliable protein count, we need to go beyond what traditional techniques offer, probing into the “subvisible” range that reveals details that are otherwise hidden. With Aura systems, you get detailed information on particles, protein and non-protein, that other methods can’t deliver, with analysis time of about 1 minute per sample and using as little as 5 µL of sample.

Frequently Asked Questions

Protein quantification is the measurement of total concentration of protein in a sample. Aura+ and Aura PTx systems quantify aggregated proteins with precision and sensitivity: Backgrounded Membrane Imaging (BMI), which delivers count, size and morphology, and Fluorescence Membrane Microscopy (FMM), which differentiates and identifies protein, cellular, and other aggregates and extrinsic particles.

Traditional quantification methods include: the Bradford/Coomasie Blue Test, Lowry Test, BCA, Biuret, and UV absorption. All of these have disadvantages, due to inaccuracies, incompatibility with common reagents, or the need for large sample sizes. Aura+ and Aura PTx systems use different technologies which have yielded more accurate protein counts by using far less samples.

Proteins can be quantified using absorbance (at 280 nm) or by using colorimetric (staining) or fluorescence methods. The Halo Labs Aura system adds another level of precision with BMI and FMM, which compares membrane images before and after samples are filtered (BMI) and uses fluorescent labels such as Thioflavin T (FMM) to identify and categorize proteins and particles in your sample. A more advanced FMM approach would be utilizing immunoassays for specific protein quantification.

At Halo Labs, we have shown that Aura instruments provide more accurate protein aggregation quantification data compared to other traditional methods.