Sponges containing tetracycline loaded-PLGA-zein microparticles as a periodontal controlled release device

Zein Nanoparticles Containing Arginine-Based Surfactants: Physicochemical Characterization and Effect on the Biological Properties

Cationic surfactants carry antimicrobial activity, based on their interaction and disruption of cell membranes. Nonetheless, their intrinsic toxicity limits their applicability. To overcome this issue, a feasible strategy consists of using solid nanoparticles to improve their delivery. The zein nanoparticles were loaded with four cationic arginine-based surfactants: one single chain Nα-lauroyl-arginine (LAM) and three Gemini surfactants Nα Nω-Bis (Nα-lauroyl-arginine) α, ω-diamide) (C₃(LA)₂, C₆(LA)₂ and C₉(LA)₂). Blank and loaded zein nanoparticles were characterized in terms of size, polydispersity and zeta potential. Furthermore, the antimicrobial activity against bacteria and yeasts and the hemolytic activity were investigated and compared to the surfactants in a solution. Nanoparticles were found to be monodisperse, presenting a size of between 180-341 nm, a pdI of <0.2 and a positive zeta potential of between +13 and +53 mV, remaining stable over 365 days. The nanoencapsulation maintained the antimicrobial activity as unaltered, while the extensive hemolytic activity found for the surfactants in a solution was reduced drastically. Nuclear Magnetic Ressonance (NMR), molecular docking and monolayer findings indicated that zein entraps the surfactants, interfering in the surfactant-membrane interactions. Accordingly, the nanoepcasulation of arginine surfactants improved their selectivity, while the cationic charges were free to attack and destroy bacteria and fungi; the aliphatic chains were not available to disrupt the cellular membranes.

Zein Nanoparticles Containing Arginine-Phenylalanine-Based Surfactants: Stability, Antimicrobial and Hemolytic Activity

Although cationic surfactants have a remarkable antimicrobial activity, they present an intrinsic toxicity that discourages their usage. In this work novel zein nanoparticles loaded with arginine-phenylalanine-based surfactants are presented. The nanoparticles were loaded with two single polar head (LAM and PNHC₁₂) and two with double amino acid polar head surfactants, arginine-phenylalanine (C₁₂PAM, PANHC₁₂). The formulations were characterized and their stability checked up to 365 days. Furthermore, the antimicrobial and hemolytic activities were investigated. Finally, NMR and molecular docking studies were carried out to elucidate the possible interaction mechanisms of surfactant-zein. The nanoparticles were obtained with satisfactory size, zeta potential and dispersibility. The surfactants containing arginine-phenylalanine residues were found to be more stable. The nanoencapsulation maintained the antimicrobial activities unaltered in comparison to the surfactants' solutions. These results are in agreement with the NMR and docking findings, suggesting that zein interacts with the surfactants by the aromatic rings of phenylalanine. As a result, the cationic charges and part of the aliphatic chains are freely available to attack the bacteria and fungi, while not available to disrupt the cellular membranes. This approach opens new possibilities for using cationic surfactants and benefits from their extraordinary antimicrobial responses for several applications.