Atomic Force microscopy techniques to investigate activated food packaging materials

Abstract

Background: Since its invention, Atomic Force Microscopy has demonstrated to be one of the most interesting and useful techniques in many fields such as biology, optics and electronics to investigate nanoscale phenomena. Not only can it provide high resolution three-dimensional imaging of surfaces, but it also allows quantitative characterization of topographies, forces, mechanical and viscoelastic properties of interfaces at nanometer level. Scope and approach: Here we review current literature in the food packaging field where AFM has been proposed for the quantitative characterization of surfaces with functional layers allowing for exploitation of preservative properties as a result for example of higher permeability or antimicrobial activity. In fact, probing microscopes allow analysis of physical or mechanical properties of interfaces providing relevant information at the nanoscale with regard to different parameters such as dimensions, shapes, evolution and adhesion. Furthermore, recent developments in AFM have shown how fast imaging techniques can be implemented to allow time evolution description even at relatively high temperatures. What we aim is to establish how AFM is effectively promising in the research and development of innovative food packaging. Key findings and conclusions: AFM is largely used to characterize (bio)plastic materials for food packaging but also the comprehension of materials modification due to their activation is approached by using AFM, frequently combined to others instrumental analysis. In particular, even though AFM is basically used for topographical analysis of activated plastic materials, new and advanced AFM analysis are carried out for the characterization of different chemical and physical properties.

Influence of Tea Tree Essential Oil and Poly(ethylene glycol) on Antibacterial and Physicochemical Properties of Polylactide-Based Films

“…Moreover, in the case of packaging films, the effectiveness of the biocides introduced into the polymer matrix is affected by the structure of these materials-mainly by the actual surface of direct contact with the bacteria cells. In order to assess the roughness of the polymer, the film analyses carried out using AFM microscopy are extremely valuable [29]. Figure 3 depicts the values of the R a (mean arithmetic deviation of the profile from the mean line), R q (mean square deviation of surface roughness) and R max (maximum distance between the highest and lowest points of the recorded image) parameters for the studied samples.…”

Microbiological and cytotoxic perspectives of active PCL/ZnO film for food packaging

“…Atomic force microscopy (AFM) AFM has been successfully introduced to surface morphology investigations, concise and effectively, AFM has been described as an analytical tool to elucidate surface characteristics of synthetic and biological materials (Jones 2016). AFM analysis is particularly suitable for active food packaging (films) due to their topographic modification as result of active substance dispersion on their surface (Marinello et al 2018). Aiming to evaluate topography and roughness on PCL/ZnO films, AFM analyses were performed, as shown in figure 4.…”

Ultrastructural and antimicrobial impacts of allyl isothiocyanate incorporated in cellulose, β‐cyclodextrin, and carbon nanotubes nanocomposites

“…Such modifications can be either beneficial, neutral, or deleterious to the final product. [45] AFM images allowed the assessment of the films' surface topography (Figure 4). It was observed that even the most homogeneous regions of the films visualized by SEM (Figure 2) showed irregularities that were detected by the AFM probe.…”