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This editorial article discusses advanced materials (AMs) and their significance in biomedical applications. AMs are materials that have improved properties compared to common counterparts and can be homogeneous or heterogeneous structures at the molecular level. They are characterized by their size, which is measured on the nanometric and micrometric scales. The development of AMs dates back to ancient times, with examples such as bronze and gold alloys. In recent years, AMs have become a focus of research in various fields, particularly in biomedical applications. The goal of this special issue is to bring together advances in material development for areas such as wound healing, cancer treatment, biosensing, and drug delivery, with the aim of improving patients' quality of life and saving lives worldwide. [Extracted from the article]

The method of electrospinning was used to create nanofibers made of cellulose acetate (CA) and essential oils (EOs). CA polymer at 15% w/v was dissolved in acetone and then 1% or 5% v/v of EOs was added to the polymer solution. The utilized essential oils were rosemary and oregano oils. Then, the CA/EOs in acetone solution were electrospun, creating micro/nanofibers, approximately 700-1500 nm in diameter. Raman spectroscopy was used to detect the attachment of the EOs in the CA electrospun fibers (ESFs). Scanning electron microscopy was used to study the morphology, topography and dimensions of the ESFs. The formed CA/EOs ESFs are found to have good antimicrobial properties against three common microbial species, frequently found in difficult to treat infections: Bacteria species Staphylococcus aureus, Escherichia coli and the yeast Candida albicans. ESFs with 5% v/v oregano oil with respect to the initial solution, showed the best antimicrobial and anti-biofilm effects due to the potency of this EO against bacteria and fungi, especially for Escherichia coli and Candida albicans. This work describes an effective and simple method to prepare CA/EOs ESFs and opens up many new applications of micro/nanofibers such as improved antimicrobial wound dressings, anti-biofilm surfaces, sensors and packaging alternatives. [ABSTRACT FROM AUTHOR]

Polylactic acid was combined with lemongrass essential oil (EO) to produce functional nanocapsules (NCs). The obtained polylactic acid nanoparticles showed antimicrobial activity both with and without the presence of lemongrass oil; however, the presence of EO improved the activity of the NCs. The presence of lemongrass assisted the formation of well-separated NCs and also provided enhanced antimicrobial properties, since lemongrass is known for its antimicrobial character. Fluorescence microscopy was used to optically observe the nanoparticles and NCs and revealed the attachment of lemongrass oil with the polylactic acid NCs. Dynamic light scattering was used to determine their size. UV absorption was used to determine the exact amount of lemongrass oil found in the polylactic acid--lemongrass oil NCs, which was important for understanding the minimum inhibitory concentration for the antimicrobial experiments. A series of clinically important microbial species were used in the study and the obtained NCs proved to have very good antimicrobial properties against all tested strains. Such NCs can be used for the design of ecological strategies, based on natural alternatives, which may be efficient against severe infections, including those that involve resistant pathogens and biofilms or those with difficult to reach localization. [ABSTRACT FROM AUTHOR]

Cellulose acetate (CA) nanoparticles were combined with two antimicrobial agents, namely lemongrass (LG) essential oil and Cu-ferrite nanoparticles. The preparation method of CA nanocapsules (NCs), with the two antimicrobial agents, was based on the nanoprecipitation method using the solvent/anti-solvent technique. Several physical and chemical analyses were performed to characterize the resulting NCs and to study their formation mechanism. The size of the combined antimicrobial NCs was found to be ca. 220 nm. The presence of Cu-ferrites enhanced the attachment of LG essential oil into the CA matrix. The magnetic properties of the combined construct were weak, due to the shielding of Cu-ferrites from the polymeric matrix, making them available for drug delivery applications where spontaneous magnetization effects should be avoided. The antimicrobial properties of the NCs were significantly enhanced with respect to CA/LG only. This work opens novel routes for the development of organic/inorganic nanoparticles with exceptional antimicrobial activities. [ABSTRACT FROM AUTHOR]

Abstract: Self-assembly of octadecyl phosphonic acid (ODPA) from solution to the (0001) plane surface of single crystal alumina is studied using atomic force microscopy (AFM), wettability measurements, transmission infrared spectroscopy and X-ray photoelectron spectroscopy (XPS). The crystals were annealed in air at 1300°C to produce a surface with terraces of 0.2nm height. This resulted in a surface comprising a mixture of terraces terminated by either oxygen or aluminium atoms. After exposure of this surface to a solution of ODPA, the XPS C1s core level reveals partial displacement of adventitious carbonaceous material by the ODPA. The phase contrast image from tapping mode AFM acquired during assembly reveals that the surface chemistries of terraces differ significantly, suggesting along with the topography images that ODPA molecules adsorbed preferentially to certain terraces. We suggest that the ODPA adsorbs preferentially to the aluminium terminated terraces that are hydroxylated in air. The adsorption to only Al-terminated terraces at the micron scale is consistent with the apparent low coverage of ODPA estimated using techniques sampling the surface on a millimetre scale including XPS and wettability measurements. This behaviour is compared to ODPA close-packed monolayer coverages formed on the amorphous oxide/hydroxide surface of aluminium metal. [Copyright &y& Elsevier]

Suberin is a biopolyester that can be extracted from bioresources such as cork trees and may find many applications in food packaging, sealing, and biomedical fields. In this work, we describe for the first time the preparation of suberin nanoparticles using the solvent/antisolvent method. Three different suberin extraction methods from cork trees were used to reveal any differences in the production and properties of the nanoparticles. trans- Cinnamaldehyde, a component of cinnamon essential oil, was added to suberin nanoparticles due to its antimicrobial and/or anticancer properties, and its synergistic effect was studied with the inherent biological properties of suberin. Interestingly, both suberin and suberin/ trans- cinnamaldehyde nanoparticles showed very good antimicrobial properties against Staphylococcus aureus and Pseudomonas aeruginosa bacteria, and also against Candida albicans (yeast). Suberin nanoparticles containing trans- cinnamaldehyde loaded with 0.1% w/w paclitaxel provided significant anticancer properties against human hepatocellular carcinoma HepG2 cancer cell lines. This study can be used to explore novel biobased polymers as efficient carriers of essential oils and drugs for infection and cancer therapy, by using minimum amount of drugs and therefore reducing their cytotoxicity and side effects.

We report the development of a method to determine the aqueous stability of self-assembled monolayers (SAMs) using the Wilhelmy plate dynamic contact angle (DCA) experiment. The DCA is measured in solutions over a range of pH values for alkyl carboxylic and alkyl phosphonic acid SAMs formed on magnetron-sputtered aluminum. The change in DCA on repeated immersion is used as a measure of the degradation of the SAMs by hydrolytic attack. The short and intermediate chain length alkyl acids are not stable in water of neutral pH, whereas molecules with the longest alkyl chains show considerably greater stability in neutral and both high and low pH solutions. The packing density inferred from the DCA and the contact angle hysteresis suggests the C18CO2H monolayer to be slightly less well packed than that of the C18P(=O)(OH)2; this is consistent with related friction force microscopy and infrared reflection absorption spectroscopy findings published elsewhere (Foster, T. T.; Alexander, M. R.; Leggett, G. J.; McAlpine, E. Langmuir 2006, 22, 9254-9259). The resistance of the SAMs to acid and alkaline environments is discussed in the context of aluminum oxide solubility, SAM packing density, and the resistance of the interfacial phosphate and carboxylate functionalities to different aqueous conditions.