Poly‐L‐lysine‐coated α‐lactalbumin nanoparticles: preparation, effect of pH, and stability under in vitro simulated gastrointestinal conditions

Abstract

BACKGROUND The development of bioactive compound delivery systems using protein‐based nanoparticles as carriers is a rapidly growing field of study. α‐Lactalbumin (α‐La) nanoparticles are adequate for this task because they are nonantigenic, biodegradable, and easily modifiable via the surface physical adsorption of other molecules. Here, the effect of poly‐L‐lysine (PLL) coating of α‐La nanoparticles on the stability against enzymatic degradation in the gastrointestinal tract was investigated. RESULTS α‐La nanoparticles were prepared by desolvation with acetone. It was observed that the pH of the initial protein suspension did not have a significant effect on the size, polydispersity index (PDI), or ζ‐potential of the nanoparticles, so the subsequent experiments were performed at pH 9, where 151.2 nm nanoparticles with a PDI of 0.072 and a ζ‐potential of −29.7 mV were obtained. The nanoparticles coating was performed with two MW‐range PLL at three concentrations. Coating efficiency increased as the polymer concentration increased and this was independent of the PLL MW. The best coating efficiency (90–95%) was obtained in the case of the 1 mg mL−1 PLL coating. Most PLL‐coated nanoparticles showed a good stability to the conditions of in vitro simulated gastrointestinal digestion compared with the uncoated nanoparticles. CONCLUSION It can be concluded that the acetone desolvation method at pH 9 is adequate to obtain α‐La nanoparticles with good characteristics. The process of PLL coating of nanoparticles showed an increase in efficiency with the increase in concentration of the polymer. The resulting coated nanoparticles had enhanced resistance to simulated gastrointestinal conditions. © 2021 Society of Chemical Industry (SCI).

Squalene-Rich Amaranth Oil Pickering Emulsions Stabilized by Native α-Lactalbumin Nanoparticles

“…It can be seen ( Figure 1 ) that the morphology of the α-LA nanoparticles, as observed by SEM, is basically spherical with particle sizes of approximately 150 nm. These sizes are consistent with the sizes determined by DLS in this study and by other authors [ 25 , 37 , 38 ] by TEM.…”

“…A minimal ζ potential of −30 mV is required for electrostatically stable nanoparticles and a minimal of −20 mV for steric stabilization [ 39 ]. Our data are consistent with the ζ potential values observed for other albumin nanoparticles [ 26 , 37 ]. These results indicate that, at the pH values used in the preparation (9 and 11) of the α-LA nanoparticles, electrostatic repulsion may play an important role in the Pickering stabilization of emulsions.…”

“…Values of PDI ≤ 0.02 are considered adequate since the nanoparticle distributions can be considered monodisperse [36]. The size and size distribution of the α-LA nanoparticles fall in the range of the results obtained by other authors using the desolvation method for the same protein [20,25,26,37]. The ζ potential for both α-LA nanoparticles was near −30 mV (−29.7 and −25.4 mV), which indicated that the two α-LA nanoparticle systems had good stability [26].…”

Special Issue: biotechnology advances in Latin America

“…Finally, Jiménez‐Cruz et al 24 . presented an outstanding work of Food Biotechnology in which a bioactive compound delivery system using protein‐based nanoparticles as carrier was developed.…”

“…Finally, Jiménez-Cruz et al 24 presented an outstanding work of Food Biotechnology in which a bioactive compound delivery system using protein-based nanoparticles as carrier was developed. These authors showed that poly-L-lysine coating resulted in enhanced resistance of ⊍-lactalbumin nanoparticles to simulated gastrointestinal conditions.…”