Since the first recombinant protein drug entered the market in 1982 (the first human insulin)¹Since its commercialization, the biopharmaceutical industry has witnessed a continuous expansion in the number of protein therapy drugs. For example, monoclonal antibodies (mAbs), growth factors, and hormones are currently used to treat cancer HIV、 Biological therapy drugs for multiple sclerosis and other diseases².The complex production process of these biological therapeutic drugs involves precise protein quantification to ensure the efficacy and quality of the final formulation.In addition, proteins are key components in various biological molecular assays for studying enzyme activity, gene expression regulation, signaling pathways, and disease mechanisms. All laboratories performing these tests will conduct protein quantification analysis to reveal complex biomolecular mechanisms.

There are currently multiple methods available for protein quantification based on the required accuracy, dynamic quantification range, compatibility with potential pollutants (detergents, reducing agents, and solvents), and differences between proteins. These methods includeDirect protein UV absorption measurement method (A)₂₈₀）Copper based assays (BCA and Lowry methods), protein dye complex absorption (Bradford), fluorescence based assays, and more complex assaysSuch as ELISA or Western Blot assays.

In this study, the fluorescence method was chosen based on its excellent sensitivity, specificity, and suitability for detecting low abundance proteins in complex biological samples.Using PerkinElmer FL 6500 ™ Fluorescence spectrometer monitoring NanoOrange^®Fluorescence enhancement was observed during non covalent interactions between fluorescent groups and BSA, and a standard curve was constructed.