Effect of the molecular weight on the physicochemical properties of poly(lactic acid) nanoparticles and on the amount of ovalbumin adsorption

Abstract

Nanopartículas de poli(ácido lactico) (PLA) foram preparadas para serem usadas como plataformas potenciais em sistemas de vacinas. PLA comercial de elevado peso molecular (PLA HMW) com M w 1,5 × 10 5 e PLA de baixo peso molecular (PLA LMW) com M w 9,3 × 10 3 foram obtidos por policondensação direta a partir de D,L ácido lático e usados para preparar nanopartículas pelo método de deslocamento de solvente. O efeito do peso molecular nas propriedades físico-químicas dos polímeros, nas dispersões das nanopartículas e na quantidade de adsorção de ovalbumina (OVA) foi estudado. PLA HMW e PLA LMW foram caracterizadas por espectroscopia de infravermelho com transformada de Fourier (FTIR), análise termogravimétrica (TGA), calorimetria diferencial de varredura de temperatura modulada (MTDSC) e cromatografia de permeação de gel (GPC). A distribuição do tamanho das partículas e potencial-ζ das dispersões obtidas foram medidas por espalhamento de luz dinâmico (DLS) e espectroscopia eletroacústica, respectivamente. A adsorção de ovalbumina em nanopartículas foi avaliada pelo método de Bradford. A dispersão de PLA LMW mostrou menores valores de potencial-ζ e tamanhos maiores comparados à dispersão de PLA HMW. Uma menor adsorção de OVA foi alcançada por PLA LMW. Poly(lactic acid) (PLA) nanoparticles were prepared to be used as potential platform for vaccine systems. Commercial high molecular weight PLA (PLA HMW) with M w 1.5 × 10 5 and low molecular weight poly(lactic acid) (PLA LMW) with M w 9.3 × 10 3 were obtained by direct polycondensation from D,L lactic acid and used to prepare nanoparticles by solvent displacement method. The effect of the molecular weight on the physicochemical properties of the polymers, on the nanoparticles dispersions and the amount of ovalbumin (OVA) adsorption was studied. The PLA HMW and PLA LMW were characterized by Fourier transformed infrared spectroscopy (FTIR), thermogravimetrical analysis (TGA), modulated temperature differential scanning calorimetry (MTDSC) and gel permeation chromatography (GPC). The particle size distribution and ζ-potential of the obtained dispersions were measured by dynamic light scattering (DLS) and electroacoustic spectroscopy, respectively. The ovalbumin adsorption on nanoparticles was evaluated by the Bradford method. PLA LMW dispersion showed lower ζ-potential values and larger sizes compared to PLA HMW dispersion. A minor OVA adsorption was achieved for PLA LMW .

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“…With PUHA BMIM, particles with heterogeneous size distribution were obtained (Figure c). From the PUEA BMIM particles with the smaller size were obtained (Figure d), with an average diameter of 240 nm, probably due to the higher molecular weight of the PLI which favors the formation of small particles …”

Cannabinoid derivate-loaded PLGA nanocarriers for oral administration: formulation, characterization, and cytotoxicity studies

“…At high molecular weight, higher hydrophobicity and smaller particle size were obtained due to longer aliphatic chains. 22,23 No differences in size were found due to the presence of terminal carboxyl groups in both cases. 22 Comparing results obtained for R502 and R752S (similar molecular weight), smaller diameters were obtained when R752S was used.…”

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