Preparation and Antibiofilm Properties of Zinc Oxide/Porous Anodic Alumina Composite Films

Abstract

The PAA (porous anodic alumina) films were prepared by two-step anodic oxidation after different times, and then the ZnO/PAA composite films were prepared by sol-gel method on their surface. Meanwhile, the ZnO/PAA composite films were characterized by X-ray diffraction (XRD), thermogravimetric/differential thermal analyzer (TG/DTA), Fourier transform infrared spectrometer (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and water contact angle (CA). The antibiofilm properties of ZnO/PAA composite films on Shewanella putrefaciens were measured simultaneously. The results show that the micromorphologies of PAA and ZnO/PAA composite films are affected by second anodization time. ZnO is a hexagonal wurtzite structure, and ZnO particles with a diameter of 10-30 nm attach to the inner or outer surfaces of PAA. After being modified by Si69, the ZnO films translate from hydrophilia to hydrophobicity. The ZnO/PAA film with the optimal antibiofilm properties is prepared on the PAA surface by two-step anodization for 40 min. The adherence of Shewanella putrefaciens is restrained by its super-hydrophobicity, and the growth of biofilm bacteria is inhibited by its abundant ZnO particles.

Keywords: Antibiofilm; Composite film; PAA/ZnO; Shewanella putrefaciens.

Fig. 1

XRD patterns of the zinc oxide powders calcined at different temperatures

Fig. 2

TG/DTA graphs for zinc oxide gelatin

Fig. 3

FT-IR spectra of the unmodified/modified zinc oxide films

Fig. 4

SEM images of the porous anodic alumina (PAA) with different times of second anodization duration a 0 min, b 40 min, c 60 min, and d 80 min

Fig. 5

SEM images of the ZnO films prepared on PAA with different time of two-step anodization duration a 0 min, b 40 min, c 60 min, and d 80 min

Fig. 6

TEM images (a, c, e, f) and SAED patterns (b, d) of the ZnO films prepared on PAA with different time of two-step anodization duration a, b 0 min c, d 40 min; e 60 min; and f 80 min

Fig. 7

The adhesion of Shewanella putrefaciens biofilm (1) and colony growth curve of the biofilm bacteria (2) on the ZnO films prepared on PAA with different time of two-step anodization duration (a) 0 min, (b) 40 min, (c) 60 min, and (d) 80 min

Fig. 8

SEM images of the biofilms on the zinc oxide films prepared on PAA with different time of two-step anodization duration a 0 min, b 40 min, c 60 min, and d 80 min

Fig. 9

CLSM images biofilms formed on the zinc oxide films prepared on PAA with different time of two-step anodization duration a 0 min, b 40 min, c 60 min, and d 80 min