Multiplatform Protein Detection and Quantification Using Glutaraldehyde-Induced Fluorescence for 3D Systems

Abstract

Glutaraldehyde (GTA) is a dialdehyde used as biological fixative and its interaction with proteins like bovine serum albumin (BSA) has been well described. Additionally, GTA is known to induce fluorescence when interacting with BSA molecules. In this work, it is developed a new sensitive and reproducible method for BSA quantification using GTA crosslinking to endow fluorescence to BSA molecules. This method can be used with standard lab equipment, providing a low cost, fast-tracking and straightforward approach for BSA quantification. Techniques such as confocal laser scanning microscopy (CLSM) and spectrofluorometry are applied for quantitative assessment, and widefield fluorescence microscopy for qualitative assessment. Qualitative and quantitative correlations between BSA content and GTA-induced fluorescence are verified. BSA concentrations as low as 62.5 μg/mL are detected using CLSM. This method can be highly advantageous for protein quantification in three-dimensional hydrogel systems, specially to evaluate protein loading/release in protein delivery or molecular imprinting systems. [Figure not available: see fulltext.].