Investigation of the Biocidal Performance of Multi-Functional Resin/Copper Nanocomposites with Superior Mechanical Response in SLA 3D Printing

Metals, such as silver, gold, and copper are known for their biocidal properties, mimicking the host defense peptides (HDPs) of the immune system. Developing materials with such properties has great importance in medicine, especially when combined with 3D printing technology, which is an additional asset for various applications. In this work, copper nanoparticles were used as filler in stereolithography (SLA) ultraviolet (UV) cured commercial resin to induce such biocidal properties in the material. The nanocomposites developed featured enhanced mechanical responses when compared with the neat material. The prepared nanocomposites were employed to manufacture specimens with the SLA process, to be tested for their mechanical response according to international standards. The process followed was evaluated with Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), energy-dispersive X-ray spectroscopy (EDS), and thermogravimetric analysis (TGA). The antibacterial activity of the fabricated nanocomposites was evaluated using the agar-well diffusion method. Results showed enhanced mechanical performance of approximately 33.7% in the tensile tests for the nanocomposites filled with 1.0 wt.%. ratios, when compared to the neat matrix material, while this loading showed sufficient antibacterial performance when compared to lower filler loadings, providing an added value for the fabrication of effective nanocomposites in medical applications with the SLA process.

Imparting biocidal properties to insulating materials made of linen fibres

In this work, salicylic acid and copper sulfate were chosen as antimicrobial agents to impart biocidal properties to nonwoven materials. The conditions of the antibacterial finishing process were as follows: the aqueous solution of a biocidal composition of different concentration was applied by spraying to the surface of the material, then the drying and heat treatment was carried out at 180°C on the thermal conductor. A microbiological study was conducted to study the fungicidal activity of the treated material. Tests were also carried out on the toxic and dermal effects of non-woven material treated with salicylic acid and copper sulfate and demonstrated its safety to human health.

Evaluation of the Mechanical and Biocidal Properties of Lapacho from Tabebuia Plant as a Biocomposite Material

The aim of this article is to discuss in detail the physicochemical properties of polylactide (PLA) reinforced by cortex fibers, which may cause bacterial mortality and increased biodegradation rates. PLA biocomposites containing cortex Lapacho fibers from Tabebuia (1–10 wt %) were prepared by extrusion and injection moulding processes. The effects of Lapacho on the mechanical and biocidal properties of the biocomposites were studied using tensile and impact tests, dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), thermogravimetry (TG), and the method of evaluating the antibacterial activity of antibacterial treated according to the standard ISO 22196:2011. It also presented the effects of Lapacho on the structural properties and biodegradation rates of biocomposites. This research study provides very important results complementing the current state of knowledge about the biocidal properties of Lapacho from Tabebuia plants and about cortex-reinforced biocomposites.

SYNTHETIC DYES IN MEDICINE

Synthetic dyes and intermediates for their synthesis are widely used in dyeing textile materials. The presence of the necessary functional groups in the structure of the dyes provides their biocidal properties. When using dyes with biocidal properties, the surface of textile materials is seized from destruction. Separate representative dyes protect the human body from the action of pathogenic microflora. It is necessary to create conditions for a timely attack by the textile material on bacteria and fungi. A sufficient number of natural and synthetic compounds exhibit antimicrobial activity. Many of these compounds are hazardous to humans and animals. Only a few chemical compounds can be recommended for practical use as antiseptic preparations. The inclusion of even a small fraction of antibacterial fibers in the structure of textile materials can provide the desired properties. The biostability of fibrous materials is influenced by the choice of dye. Not all dyes that have bactericidal activity in their pure form exhibit it when applied to textile material. For the manifestation of these functions, dyes must have groups responsible for their bacteriological activity. In developed countries, attempts are being made to uniform dyeing and bioprotective processing of textile materials. The combination of these processes is not only theoretical but also a promising area of ​​research. When creating antibacterial textile materials, nanotechnology is being actively introduced. The use of nanotechnology reduces the cost of raw materials and materials. At the same time, the most promising for use in medicine are nanomaterials that meet the following requirements, such as biocompatibility and programmability of a positive effect on a biological object. Thus, the article analyzes the scientific literature in the field of dyes with biocidal properties.