Cotton fabric functionalisation with menthol/PCL micro- and nano-capsules for comfort improvement.

OBJECTIVE: Cotton functionalisation with poly-ɛ-caprolactone (PCL) micro- and nano-capsules containing menthol was carried out with the aim of introducing a long-lasting refreshing sensation. MATERIALS AND METHODS: The preparation of the polymer micro- and nano-capsules was carried out by solvent displacement technique. A confined impinging jets mixer was used in order to ensure fast mixing and generate a homogeneous environment where PCL and menthol can self-assemble. RESULTS: The micro- and nano-capsules and the functionalised fabrics were characterised by means of DSC, FT-IR spectroscopy and SEM imaging. Micro- and nano-capsules of different size, from about 200 to about 1200 nm, were obtained varying menthol to PCL ratio (from 0.76 to 8), overall concentration and flow rate (i.e. mixing conditions). The inclusion of menthol was confirmed by DSC analysis. DISCUSSION AND CONCLUSION: A patch test was carried out by 10 volunteers. Micro-capsules were found to be effective in conferring the fabric a refreshing sensation without altering skin physiology.

Intelligent polarization-sensitive holographic flow-cytometer: Towards specificity in classifying natural and microplastic fibers.

Micron size fiber fragments (MFFs), both natural and synthetic, are ubiquitous in our life, especially in textile clothes, being necessary in modern society. In the Earth's aquatic ecosystem, microplastic fibers account for ~91% of microplastic pollution, thus deserving notable attention as one of the most alarming ecological problems. Accurate automatic identification of MFFs discharges in specific upstream locations is highly demanded. Computational microscopy based on Digital Holography (DH) and machine learning has been demonstrated to identify microplastics in respect to microalgae. However, DH is a non-specific optical tool, meaning it cannot distinguish different types of plastic materials. On the other hand, materials-specific assessments are pivotal to establish the environmental impact of different textile products and production processes. Spectroscopic assays can be employed to identify microplastics for their intrinsic specificity, although they are generally low-throughput and require large concentrations to enable effective measurements. Conversely, MFFs are usually finely dispersed within a water sample. Here we rely on a polarization-resolved holographic flow cytometer in a Lab-on-Chip (LoC) platform for analysing MFFs. We demonstrate that two important objectives can be achieved, i.e. adding material specificity through polarization analysis while operating in a microfluidic stream modality. Through a machine learning numerical pipeline, natural fibers (i.e. cotton and wool) can be clearly separated from synthetic microfilaments, namely PA6, PA6.6, PET, PP. Moreover, the proposed system can accurately distinguish between different polymers under investigation, thus fulfilling the specificity goal. We extract and select different features from amplitude, phase and birefringence maps retrieved from the digital holograms. These are shown to typify MFFs without the need for sample pre-treatment or large concentrations. The simplicity of the DH method for identifying MFFs in LoC-based flow cytometers could promote the use of polarization resolved field-portable analysis systems suitable for studying pollution caused by washing processes of synthetic textiles.

Preparation and analysis of standards containing microfilaments/microplastic with fibre shape.

Synthetic clothing represents a primary source of environmental pollution because of shedding of microfilaments during laundry washing or in textile processes. Although many approaches can be used for the evaluation of microplastic, there are no precise guideline to follow for the analysis labs. Here, an accurate method for the preparation of microfilaments standard suspensions to facilitate lab tests and the monitoring of microplastic in different matrices was developed. Different standard suspensions were prepared by using five different synthetic threads consisting of a different number of filaments cut with a predetermined length of 0.2 mm suspended in three different volumes of water. The suspensions were filtered and the microfilaments were counted. The number of microfilaments for each polymer solution were statistically elaborated with a logit model and the results showed that the probability of detecting them is higher than 95% when the concentration of microfilaments/L is lower than 200. Moreover, a relationship between the theoretical microfilaments contained in the samples and the detection probability of the single microfilament, for each suspension volume was highlighted.

Contribution of microplastic particles to the spread of resistances and pathogenic bacteria in treated wastewaters.

Microplastic Particles (MPs) are ubiquitous pollutants widely found in aquatic ecosystems. Although MPs are mostly retained in wastewater treatment plants (WWTPs), a high number of MPs reaches the open waters potentially contributing to the spread of pathogenic bacteria and antibiotic resistance genes in the environment. Nowadays, a limited number of studies have focused on the role of MPs as carriers of potentially pathogenic and antibiotic resistant bacteria in WWTPs. Thus, an investigation on the community composition (by 16S rRNA gene amplicon sequencing) and the abundance of antibiotic and metal resistance genes (by qPCR) of the biofilm on MPs (the plastisphere) and of planktonic bacteria in treated (pre- and post-disinfection) wastewaters was performed. MPs resulted to be very similar in terms of type, color, size, and chemical composition, before and after the disinfection. The bacterial community on MPs differed from the planktonic community in terms of richness, composition, and structure of the community network. Potentially pathogenic bacteria generally showed higher abundances in treated wastewater than in the biofilm on MPs. Furthermore, among the tested resistance genes, only sul2 (a common resistance gene against sulfonamides) resulted to be more abundant in the plastisphere than in the planktonic bacterial community. Our results suggest that the wastewater plastisphere could promote the spread of pathogenic bacteria and resistance genes in aquatic environment although with a relatively lower contribution than the wastewater planktonic bacterial community.

Assessment of microplastics release from polyester fabrics: The impact of different washing conditions.

Synthetic fibers account for approximately 60% of the total global fiber production, and polyester (PET) and polyamide (PA) dominate. Synthetic fabrics are now widely used in clothing, upholstery, carpets and other such materials. Textiles based on these materials have the potential to release microplastics (<5 mm in size) into the environment during production and cleaning actions. These particles are released in sewage effluents, as washing machine filters and wastewater treatment plants are not specifically designed to retain them and represent an environmental pollution that continuously increases the scientific and societal concern about their effects on marine biota and ecosystems. This study was focused on the determination of the amount of microfibers release from 100% polyester fabrics, in different washing conditions (programs and temperatures), comparing the use of detergent alone vs detergent with a stain remover. Microplastics released were characterized and quantified with gravimetric analysis, different microscopic, spectroscopic and thermal techniques. Tests were carried out in replicates to assess the data reproducibility and to show statistical differences between washing conditions.

Evaluation of microplastic release caused by textile washing processes of synthetic fabrics.

A new and more alarming source of marine contamination has been recently identified in micro and nanosized plastic fragments. Microplastics are difficult to see with the naked eye and to biodegrade in marine environment, representing a problem since they can be ingested by plankton or other marine organisms, potentially entering the food web. An important source of microplastics appears to be through sewage contaminated by synthetic fibres from washing clothes. Since this phenomenon still lacks of a comprehensive analysis, the objective of this contribution was to investigate the role of washing processes of synthetic textiles on microplastic release. In particular, an analytical protocol was set up, based on the filtration of the washing water of synthetic fabrics and on the analysis of the filters by scanning electron microscopy. The quantification of the microfibre shedding from three different synthetic fabric types, woven polyester, knitted polyester, and woven polypropylene, during washing trials simulating domestic conditions, was achieved and statistically analysed. The highest release of microplastics was recorded for the wash of woven polyester and this phenomenon was correlated to the fabric characteristics. Moreover, the extent of microfibre release from woven polyester fabrics due to different detergents, washing parameters and industrial washes was evaluated. The number of microfibres released from a typical 5 kg wash load of polyester fabrics was estimated to be over 6,000,000 depending on the type of detergent used. The usage of a softener during washes reduces the number of microfibres released of more than 35%. The amount and size of the released microfibres confirm that they could not be totally retained by wastewater treatments plants, and potentially affect the aquatic environment.