Development and characterization of ZnO piezoelectric thin films on polymeric substrates for tissue repair

Abstract

Currently available scaffolds for tissue repair have shown very limited success, so many efforts have being put in the development of novel functional materials capable of regulating cell behavior and enhance the tissue healing rate. Piezoelectric materials, as zinc oxide (ZnO), can be a very interesting solution for scaffold development, as they can deliver electrical signals to cells upon mechanical solicitation, allowing the development of suitable microenvironments for tissue repair. This way, it is reported the deposition of ZnO thin films on a polymer by direct current magnetron sputtering, under different conditions, in order to obtain a piezoelectric ZnO thin film with potential for tissue repair applications. The obtained ZnO thin films were characterized in terms of morphology, crystallography, electrical conductivity, transmittance, piezoelectricity, and adhesion quality. The deposition process resulted in uniform films, with a very good adhesion to the substrate. The different deposition conditions influenced the evolution of the crystalline domains and preferential growths and consequently, the electrical properties of the films. One of the conditions resulted in a thin film with a high piezoelectric coefficient and a conductor behavior, being considered the most promising to act as a bioactive coating. K E Y W O R D S magnetron sputtering, PET, piezoelectricity, tissue repair, ZnO

Construction of Bio‐Piezoelectric Platforms: From Structures and Synthesis to Applications

“…As a result, electrons are able to collide with gas molecules, thereby increasing the ionization rate of plasma. [ 82 ] Under the action of a high‐voltage electric field, the plasma collides with the target to release target atoms, which subsequently travel to the substrate and form a thin film, as seen in Figure . [ 25c,81 ] Magnetron sputtering can produce thin films with tailored piezoelectricity and conductivity via controlling deposition conditions, such as gas flow rate, substrate temperature, deposition rate, sputtering gas pressure, and annealing conditions.…”

“…deposited a series of ZnO bio‐piezoelectric thin films through varying the oxygen flux during a direct current magnetron sputtering process. [ 82a ] The obtained ZnO thin film was well adhered to the PET substrate with a uniform film structure and good mechanical strength. At the same time, the surface deposition of ZnO thin film increased the surface energy and hydrophobicity of the PET substrate surface.…”

“…As a result, the ZnO thin film prepared under an oxygen flux possessed a high piezoelectric coefficient and good adhesion to the substrate. [ 82a ]…”

Exercise-induced piezoelectric stimulation for cartilage regeneration in rabbits

“…A combination of piezoelectric scaffolds with exercise-induced joint movement could control the produced charge and achieve improved healing of hyaline cartilage. Unfortunately, common piezoelectric materials including lead zirconate titanate (PZT) ( 28 , 29 ), polyvinylidene fluoride (PVDF) ( 30 ), and zinc oxide ( 31 , 32 ) are either nonbiodegradable (PVDF and PZT) or toxic (PZT).…”

Development and Characterization of ZnO Piezoelectric Thin Film Sensors on GH4169 Superalloy Steel Substrate by Magnetron Sputtering

“…From the measurement results, the average value of the longitudinal piezoelectric coefficient was 1.36 Pc/N, lower than the previously reported results of 1.5 pC/N–5.7 pC/N [ 46 ]. There may be influencing factors, such as different substrates, different thickness of ZnO films, the effect of the electrode material and buffer layer, different sputtering equipment, effects of testing equipment and testing methods [ 47 , 48 , 49 ]. However, although the test results are slightly lower than the fabrication results on silicon wafer, it also proves that its application to the fabrication of smart bolts is feasible.…”