Authors: Alexander E Yarawsky, Paola Cardenas Lopez, Johannes Walter, Michael T DeLion, Lake N Paul. A fundamental approach to buoyant density determination by DGE-AUC. Analytical Biochemistry, volume 704, 115907 (2025). DOI: Click Here

About This Research

Density gradient equilibrium analytical ultracentrifugation has experienced renewed interest for characterizing cell and gene therapeutics, yet existing methods rely on reference standards and assumptions about gradient behavior that limit accuracy. This work presents a model-independent approach to buoyant density determination that eliminates the need for reference materials while accounting for pressure effects, solvent compressibility, and nonideal gradient behavior. Demonstrated across diverse systems including NISTmAb and DNA in CsCl gradients and polystyrene beads in sucrose gradients, this fundamental method provides unprecedented flexibility for characterizing particles of various compositions.

Why This Matters

As the authors emphasize, “there is ample evidence in the vast density gradient literature that indicates the presence of pressure effects, solvent compressibility, and general nonideal behavior” that complicate traditional approaches. This breakthrough methodology enables accurate buoyant density determination without standards, addressing a critical need in characterizing emerging therapeutics where reference materials may not exist – expertise that positions BioAnalysis at the forefront of advanced analytical methods for next-generation biologics.