Aim: The aim of this study was to investigate the selected properties of zinc oxide- polymethyl methacrylate (ZnO-PMMA) nanocomposites that can influence the microorganism deposition on their surface. Materials and Methods: Non-commercial ZnO-NPs were prepared, characterized and used for the preparation of PMMA nanocomposite. Roughness, absorbability, contact angle and hardness of this new nanomaterial were evaluated. PMMA without ZnO-NPs served as control. Outcomes: Compared to unenriched PMMA, incorporation of ZnO-NPs to 7.5% for PMMA nanocomposite increases the hardness (by 5.92%) and the hydrophilicity. After modification of the material with zinc oxide nanoparticles the roughness parameter did not change. All tested materials showed absorption within the range of 1.82 to 2.03%, which meets the requirements of International Organization for Standardization (ISO) standards for denture base polymers. Conclusions: The results showed no significant deterioration in the properties of acrylic resin that could disqualify the nanocomposite for clinical use. Increased hydrophilicity and hardness with absorbability within the normal range can explain the reduced microorganism growth on the denture base, as has been proven in a previous study.

Here we show that gold nanocages (AuNCs) can be used as receptor materials for nanomechanical Membrane-type Surface stress Sensor (MSS). The fabricated AuNCs-coated MSS (AuNCs_MSS) was employed successfully for the recognition of small volatile molecules. Each AuNCs_MSS exhibited a specific pattern of the response signal to each analyte, enabling groupwise discrimination of the compounds by means of principal component analysis (PCA). The application of contour maps of analytes-distinctive features on the PCA plots allows us to recognize polarity as a key property which affects the AuNCs_MSS response. In addition, density functional theory (DFT) calculations suggest that corners and edges of the nanocages play important roles on the binding energy.

The assembly of biomolecules onto mechanically and chemically stable inorganic structures is advantageous for practical applications considering the potential for improvements in the stability and catalytic functionality of biomaterials. In this research, we have utilized hierarchically-structured, radially porous silica hollow spheres as a platform for hemoprotein self-assembly. Proteins adsorbed onto silica surfaces through electrostatic interactions remained intact and exhibited rapid gas-phase sensing activity towards hydrogen sulfide gas. The nanoscale molecular interactions between hemoproteins and the analyzed gases were transduced into measurable variations in electric signals using a nanomechanical Membrane-type Surface stress Sensor (MSS).

The Front Cover shows molecules of redox protein cytochrome c immobilized on the metallic coating from magnetite nanoparticles decorated with near‐monodisperse gold nanoparticles, which are used as colloidal building blocks for the magnetic assembly of mesoporous framework.More information can be found in the Article by Antonio F. A. A. Melo et al.