Adsorption of albumin, collagen, and fibronectin on the surface of poly(hydroxybutyrate-hydroxyvalerate) (PHB/HV) and of poly(ε-caprolactone) (PCL) films modified by an alkaline hydrolysis and of poly(ethylene terephtalate) (PET) track-etched membranes

Abstract

The effect of alkaline hydrolysis on several surface properties of poly(hydroxybutyrate-hydroxyvalerate) (92/8) (PHB/HV) and poly(epsilon-caprolactone) (PCL) films and of poly(ethylene terephtalate) (PET) track-etched membranes have been characterized, as well as the adsorption of three proteins normally encountered by mammalian cells in vivo, namely albumin, collagen, and fibronectin. The water contact angle decreases and the number of -COOH functions accessible to a chemical reaction at the surface of PCL increases with alkaline hydrolysis. Analysis by atomic force microscopy pictures reveals a change in surface morphology. The modifications of surface properties are correlated with a two times increase of the adsorption of three radiolabelled proteins. The hydrolysis results in a slight increase in the water contact angle of one face of the PHB/HV film and a sharp increase in the number of -COOH functions. Important morphology changes are also induced. The adsorption of the radiolabelled proteins is almost 100 times higher on the hydrolyzed polymer than on the native surface. The increase in hydrophilicity of different PET batches correlates to an increase in the number of -COOH functions. Nevertheless, the surface chemical composition and rugosity are constant and no significant difference in the amount of radiolabelled fibronectin adsorbed on the different surfaces is detectable. In conclusion, the effect of hydrolysis on the surface properties of each of the polyesters studied as well as the proteins adsorption on the different surfaces are different. The results strongly support the hypothesis that, in the system studied, parameters other than hydrophilicity influence protein adsorption: the main parameters that might play a role are the total surface area accessible to the proteins, as well as the surface chemical composition.

Surface functionalization of PHBV by HEMA grafting via UV treatment: Comparison with thermal free radical polymerization

“…Control of the films surface properties, such as wettability, adsorption, chemistry, charge, roughness, and rigidity 10,11 is important when polymeric material is in contact with cells. To trigger the cell-matrix adhesion on polymer surfaces, several surface modification techniques have been recently applied, including alkaline hydrolysis, 12,13 implantation, 14 gamma irradiation, 15 oxygen plasma treatment, 16 UV, 17 or ozone 18 followed by chemical grafting. 19 Surface modification of polymer films offers versatile means for incorporating new functionalities.…”

Adsorção de fibronectina a arcabouços de polihidroxibutirato aplicáveis à engenharia óssea

“…Como a adsorção de proteínas é sensível às propriedades químicas da superfície, o resultado do teste in vitro pode estar relacionado com a possí- A estrutura terciária da FN pode sofrer alterações de acordo com o ambiente no qual se encontra. As conformações assumidas pela FN são determinadas por interações eletrostáticas [12] . Sendo assim, a diferença observada na morfologia dos filmes pode estar associada, dentre vários fatores, à composição química das superfícies dos arcabouços.…”

“…Sendo assim, a preparação da superfície de polímeros para a imobilização de proteínas, em geral, envolve a ativação e/ou a inserção destes grupos funcionais específicos [11] . Exemplos de ativação da superfície através de tratamentos químicos são encontrados na literatura [6,12] . Thiré e colaboradores [6] utilizaram um tratamento químico via úmida com base na aminólise por etilenodiamina para introduzir grupamentos amino e hidroxílicos na superfície de filmes de PHB.…”

“…O outro grupo amino não reagido ficou livre. Durante este processo, grupos hidroxilas (oriundos da reação de hidrólise) também foram incorporados à superfície do poliéster [11,12] . O presente trabalho teve como objetivo ativar biologicamente a superfície de arcabouços de PHB por meio da adsorção de FN.…”

Functionalization of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) films via surface‐initiated atom transfer radical polymerization: Comparison with the conventional free‐radical grafting procedure

“…It is widely known that the adhesion and proliferation of different types of cells on polymeric materials depend on the surface characteristics, such as wettability (hydrophilicity or surface free energy), chemistry, charge, roughness, and rigidity. 7,8 To trigger the cell-matrix adhesion on PHAs surfaces, several surface-modification techniques have been recently been applied, including alkaline hydrolysis, 9,10 ion implantation, 11 oxygen plasma treatment, 12 c irradiation, 13 and irradiation with UV light 14 or ozone 15 followed by chemical grafting. 16 Grafting has been considered the most convenient technique for modifying the physical and chemical properties of polymer surfaces because the effects of other treatments, which form polar groups on the surface, are not significant enough.…”