Multiwavelength Transmission (MWT) UV-Vis-NIR spectroscopy, an effective technique often underutilized for the characterization of processes involving particulates, such as protein aggregation, is systematically explored using bovine serum albumin and a set of NIST-traceable particle size (PS) standards having certified particle diameters over the nominal size range of 30 to 100 nm. The PS standards are used as surrogates for protein aggregates and other contaminants such as oils and microbubbles. Therefore, the standards can be used to quantitatively modify the optical properties of protein solutions and thus observe the effect of the presence of aggregates and other particulates on their wavelength-dependent transmission spectra. The experimental results demonstrate that the changes induced in the optical density spectra of proteins due to the presence of PS particles are detectable and consistent with the expectations set by light scattering theory. It is demonstrated that the size and relative concentrations of the particle populations present in the protein samples can be quantified. Because of the considerable dynamic range of MWT UV-Vis-NIR spectroscopy for particle analysis and its real-time measurement capabilities, this type of spectroscopy can be effectively used for the characterization of protein aggregates and for the continuous real-time monitoring of aggregation processes and for the identification and quantification of contaminants in protein-based products.
Nanoparticles/chemistry , Polystyrenes/chemistry , Proteins/chemistry , Spectrum Analysis/methods , Animals , Cattle , Models, Chemical , Particle Size , Reference Standards , Serum Albumin, Bovine
Multiwavelength transmission ultraviolet-visible-near-infrared (UV-Vis-NIR) spectroscopy is an effective technique that has not yet been fully exploited for the characterization of products of protein and particle interactions. Here, it is explored by using bovine serum albumin and National Institute of Standards and Technology-traceable particle size standard having a nominal diameter of 20 nm. Adsorption of bovine serum albumin to the particles is quantitatively ascertained through its effect on the wavelength-dependent transmission spectra of protein and particle mixtures. The experimental results demonstrate that the changes induced in the transmission spectra of protein and particle mixtures because of protein adsorption on particles are detectable and consistent with the expectations set by the light-scattering theory. The size, structure, composition, and relative concentrations of the particle populations present in the protein-particle mixtures can be quantified. Given the considerable dynamic range of multiwavelength transmission UV-Vis-NIR spectroscopy for particle analysis and its real-time measurement capabilities, this type of spectroscopy can be effectively used for the characterization of the products of protein-particle interaction and for the continuous real-time monitoring of interaction processes.
Nanoparticles/chemistry , Polystyrenes/chemistry , Serum Albumin, Bovine/chemistry , Animals , Cattle , Particle Size , Spectrophotometry, Ultraviolet , Spectroscopy, Near-Infrared
