Developing textile sustainability education in the curriculum: pedagogical approaches to material innovation in fashion.

The textile industry needs to adopt environmentally sustainable approaches to address ecologically damaging practices. Whilst driven by initiatives such as Textiles 2030, it is current students who will carry this agenda forward. This project investigated pedagogical approaches to develop sustainable textiles for the fashion design curriculum. Pilot studies, using bacterial cellulose (BC) as a material for millinery, revealed members of the public were prepared to experiment with this novel material, and BC was compatible with traditional hat-making techniques. A further study challenged secondary school students, based on an experiential learning model, to grow their own BC biofilm, exploring this as a sustainable apparel fabric. Initial attitudes of reluctance developed into acceptance once engaged in the practical activity. This study illustrates that with appropriate communication and education strategies, the principles of sustainability in fashion, and the acceptability of novel materials, can be engendered in different audiences.

Effects of Cationic and Anionic Surfaces on the Perpendicular and Lateral Forces and Binding of Aspergillus niger Conidia.

The binding of conidia to surfaces is a prerequisite for biofouling by fungal species. In this study, Aspergillus niger subtypes 1957 and 1988 were used which produced differently shaped conidia (round or spikey respectively). Test surfaces were characterised for their surface topography, wettability, and hardness. Conidial assays included perpendicular and lateral force measurements, as well as attachment, adhesion and retention assays. Anionic surfaces were less rough (Ra 2.4 nm), less wettable (54°) and harder (0.72 GPa) than cationic surfaces (Ra 5.4 nm, 36° and 0.5 GPa, respectively). Perpendicular and lateral force assays demonstrated that both types of conidia adhered with more force to the anionic surfaces and were influenced by surface wettability. Following the binding assays, fewer A. niger 1957 and A. niger 1988 conidia bound to the anionic surface. However, surface wettability affected the density and dispersion of the conidia on the coatings, whilst clustering was affected by their spore shapes. This work demonstrated that anionic surfaces were more repulsive to A. niger 1998 spores than cationic surfaces were, but once attached, the conidia bound more firmly to the anionic surfaces. This work informs on the importance of understanding how conidia become tightly bound to surfaces, which can be used to prevent biofouling.

Hands on Biofilm! Utilizing a public audience in a citizen science project to assess yield variability when culturing kombucha pellicle.

The pellicle biofilm generated during the Kombucha tea fermentation process has, when dried, textile-like properties that may have real-life applications. However, pellicle yield can vary depending on inoculation and incubation conditions, which affects research investigations on the properties of the pellicle. To generate data on variability to help define optimum pellicle growth conditions, as part of a public engagement event about biofilm, a citizen science activity was hosted whereby visitors to a science festival were invited to select incubation conditions and inoculate different media with liquid or solid (pellicle). More than 220 samples were inoculated (in excess of 1200 visitors, mainly in family groups). The most popular incubation conditions were coconut water or tea medium, 30°C/room temperature and liquid inoculum. The most productive/reproducible in terms of yield and variability were tea medium, 30°C, and liquid inoculum, which reflect some of the conditions most used in the domestic setting for kombucha culture. The event provided both useful research data and generated public interest in a research area of which many will have been unaware. Interest in the results of the activity, available several weeks after the activity, was sustained using email contact and FlickR for the dissemination of images and data.

Hands On Biofilm! A multidisciplinary public engagement event using kombucha tea pellicle as an accessible example of biofilm.

Public engagement with science has become increasingly important for the scientific community. There are many documented public engagement events that focus on aspects of microbiology, but relatively few utilise biofilms as a topic, despite their importance. Kombucha tea pellicles are easy to grow biofilms, facilitating their use within the public domain as examples of these complex communities. The aim of this work was to deliver a public engagement event that introduced visitors to general concepts about biofilm, and applications around sustainability, using kombucha. The event encouraged visitors to: build a biofilm using model clay; inoculate kombucha tea cultures using different incubation conditions, as part of a citizen science experiment to assess impact on pellicle biofilm yield; create garments and drapes on mini-mannequins using dried kombucha pellicle fabric, and demonstrate the range and importance of fermented foods (including kombucha tea), and 'good bacteria'. Quantitative and qualitative indicators of engagement were built into the activities. More than 1200 visitors, mainly in family groups, visited the event over a 4-h period. Knowledge of biofilms was low at the beginning of the event. Participation in all activities was high. Indicators of quantitative engagement were impressive, but it was difficult to obtain qualitative evidence other than observations from the delivery team (nineteen members) because of the intensity of the event and volume of visitors. The event was clearly successful in terms of fulfilment of aims, audience engagement and enthusiasm: the embedded evaluations helped to evidence the impact and reach of the event, enabling confidence in dissemination of good practice in the enhancement of public understanding of the importance of biofilm in general, and kombucha in particular.

Lateral force removal of fungal spores to demonstrate how surface properties affect fungal spore retention.

Microbial biofouling on polymer surfaces can lead to their biodeterioration. This may result in deterioration of the surface, leading to cracking and fracturing. Fungal spores from Aspergillus niger 1957, Aspergillus niger 1988 and Aureobasidium pullulans were tested to determine their strength of attachment on three surfaces, p(γ-MPS-co-MMA), p(γ-MPS-co-LMA) and spin-coated poly(methyl methacrylate) (PMMAsc), using lateral force measurements. The results demonstrate that A. niger 1957 and A. niger 1988 spores were most easily removed from the p(γ-MPS-co-MMA) surface, which was the surface with the highest Ra value. The A. niger 1957 and A. pullulans spores were most difficult to remove from the PMMAsc surface, which was the hardest surface. A. niger 1988 spores were the most difficult to remove from p(γ-MPS-co-LMA), the most hydrophobic surface. The results with A. pullulans were difficult to elucidate since the spores bound to all three surfaces and were removed with similar rates of force. The lateral force results demonstrate that spore attachment to a surface is a multi-factorial process, and independent surface and microbial factors influence spore binding. Thus, each environmental scenario needs to be considered on an individual basis, since a solution to one biofouling issue will probably not translate across to other systems. This article is part of the theme issue 'Nanocracks in nature and industry'.

Reproducibility of Bacterial Cellulose Nanofibers Over Sub-Cultured Generations for the Development of Novel Textiles.

The textile industry is in crisis and under pressure to minimize the environmental impact on its practices. Bacterial cellulose (BC), a naturally occurring form of cellulose, displays properties superior to those of its cotton plant counterpart, such as enhanced purity, crystallinity, tensile strength, and water retention and is thus suitable for an array of textile applications. It is synthesized from a variety of microorganisms but is produced in most abundance by Komagataeibacter xylinus. K. xylinus is available as a type strain culture and exists in the microbial consortium commonly known as Kombucha. Whilst existing literature studies have described the effectiveness of both K. xylinus isolates and Kombucha in the production of BC, this study investigated the change in microbial communities across several generations of sub-culturing and the impact of these communities on BC yield. Using Kombucha and the single isolate strain K. xylinus as inocula in Hestrin and Schramm liquid growth media, BC pellicles were propagated. The resulting pellicles and residual liquid media were used to further inoculate fresh liquid media, and this process was repeated over three generations. For each generation, the thickness of the pellicles and their appearance under SEM were recorded. 16S rRNA sequencing was conducted on both pellicles and liquid media samples to assess changes in communities. The results indicated that the genus Komagataeibacter was the most abundant species in all samples. Cultures seeded with Kombucha yielded thicker cellulose pellicles than those seeded with K. xylinus, but all the pellicles had similar nanofibrillar structures, with a mix of liquid and pellicle inocula producing the best yield of BC after three generations of sub-culturing. Therefore, Kombucha starter cultures produce BC pellicles which are more reproducible across generations than those created from pure isolates of K. xylinus and could provide a reproducible sustainable model for generating textile materials.

Multifractal Analysis to Determine the Effect of Surface Topography on the Distribution, Density, Dispersion and Clustering of Differently Organised Coccal-Shaped Bacteria.

The topographic features of surfaces are known to affect bacterial retention on a surface, but the precise mechanisms of this phenomenon are little understood. Four coccal-shaped bacteria, Staphylococcus sciuri, Streptococcus pyogenes, Micrococcus luteus, and Staphylococcus aureus, that organise in different cellular groupings (grape-like clusters, tetrad-arranging clusters, short chains, and diploid arrangement, respectively) were used. These differently grouped cells were used to determine how surface topography affected their distribution, density, dispersion, and clustering when retained on titanium surfaces with defined topographies. Titanium-coated surfaces that were smooth and had grooved features of 1.02 µm-wide, 0.21 µm-deep grooves, and 0.59 µm-wide, 0.17 µm-deep grooves were used. The average contact angle of the surfaces was 91°. All bacterial species were overall of a hydrophobic nature, although M. luteus was the least hydrophobic. It was demonstrated that the 1.02 µm-wide featured surface most affected Strep. pyogenes and S. sciuri, and hence the surfaces with the larger surface features most affected the cells with smaller dimensions. The 0.59 µm featured surface only affected the density of the bacteria, and it may be suggested that the surfaces with the smaller features reduced bacterial retention. These results demonstrate that the size of the topographical surface features affect the distribution, density, dispersion, and clustering of bacteria across surfaces, and this is related to the cellular organisation of the bacterial species. The results from this work inform how surface topographical and bacterial properties affect the distribution, density, dispersion, and clustering of bacterial retention.

How Do We Determine the Efficacy of an Antibacterial Surface? A Review of Standardised Antibacterial Material Testing Methods.

Materials that confer antimicrobial activity, be that by innate property, leaching of biocides or design features (e.g., non-adhesive materials) continue to gain popularity to combat the increasing and varied threats from microorganisms, e.g., replacing inert surfaces in hospitals with copper. To understand how efficacious these materials are at controlling microorganisms, data is usually collected via a standardised test method. However, standardised test methods vary, and often the characteristics and methodological choices can make it difficult to infer that any perceived antimicrobial activity demonstrated in the laboratory can be confidently assumed to an end-use setting. This review provides a critical analysis of standardised methodology used in academia and industry, and demonstrates how many key methodological choices (e.g., temperature, humidity/moisture, airflow, surface topography) may impact efficacy assessment, highlighting the need to carefully consider intended antimicrobial end-use of any product.

Analysis of university student responses to the pandemic in a formal microbiology assessment.

During the coronavirus pandemic, second-year students on the B.Sc. molecular biology and genetics degree at Istanbul Technical University sat an open-ended online exam for a microbiology course in which one of the compulsory questions asked how the course had helped them during the first phase of the pandemic (April-July 2020). Fifty of 69 students gave consent for their (anonymous) responses to be analysed in order to discern any key ways in which their knowledge had been applied. The aim of the study was to investigate whether taking an advanced microbiology course increases understanding of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic and has a positive impact on student behaviours with respect to public health practices. Findings were divided into four major themes: course content (information), application of course content to behavioural change (practice), professionalism and their 'audience' whilst at home in lockdown (family and friends). Social distancing, wearing face masks, and hand and surface hygiene were described as important behaviours, with this practice informed by their basic microbiology knowledge. This paper describes a scenario where rote assessment can be used to assess wider scientific literacy with respect to application in society, providing students with an opportunity to incorporate and apply their learning into real-life situations, whilst tutors can assess constructivist learning, conceptual understanding and impact on student behaviour.

Biofilm associated genotypes of multiple antibiotic resistant Pseudomonas aeruginosa.

BACKGROUND: Pseudomonas aeruginosa is a ubiquitous environmental microorganism and also a common cause of infection. Its ability to survive in many different environments and persistently colonize humans is linked to its presence in biofilms formed on indwelling device surfaces. Biofilm promotes adhesion to, and survival on surfaces, protects from desiccation and the actions of antibiotics and disinfectants. RESULTS: We examined the genetic basis for biofilm production on polystyrene at room (22 °C) and body temperature (37 °C) within 280 P. aeruginosa. 193 isolates (69 %) produced more biofilm at 22 °C than at 37 °C. Using GWAS and pan-GWAS, we found a number of accessory genes significantly associated with greater biofilm production at 22 °C. Many of these are present on a 165 kb region containing genes for heavy metal resistance (arsenic, copper, mercury and cadmium), transcriptional regulators and methytransferases. We also discovered multiple core genome SNPs in the A-type flagellin gene and Type II secretion system gene xpsD. Analysis of biofilm production of isolates of the MDR ST111 and ST235 lineages on stainless-steel revealed several accessory genes associated with enhanced biofilm production. These include a putative translocase with homology to a Helicobacter pylori type IV secretion system protein, a TA system II toxin gene and the alginate biosynthesis gene algA, several transcriptional regulators and methytransferases as well as core SNPs in genes involved in quorum sensing and protein translocation. CONCLUSIONS: Using genetic association approaches we discovered a number of accessory genes and core-genome SNPs that were associated with enhanced early biofilm formation at 22 °C compared to 37 °C. These included a 165 kb genomic island containing multiple heavy metal resistance genes, transcriptional regulators and methyltransferases. We hypothesize that this genomic island may be associated with overall genotypes that are environmentally adapted to survive at lower temperatures. Further work to examine their importance in, for example gene-knockout studies, are required to confirm their relevance. GWAS and pan-GWAS approaches have great potential as a first step in examining the genetic basis of novel bacterial phenotypes.

Using fiction to engage audiences with infectious disease: the effect of the coronavirus pandemic on participation in the Bad Bugs Bookclub.

During Bad Bugs Bookclub meetings, scientists and non-scientists discuss novels in which infectious disease forms part of the plot in order to encourage public understanding of, and engagement with, microbiology. The website presents meeting reports and reading guides for over 70 novels. The aim of this work was to raise awareness of the bookclub and increase website engagement. In 2019, events designed to reach new audiences maintained an increase in page views from the end of 2018 (around 200 per month). In 2020, the coronavirus pandemic forced bookclub meetings online (Zoom). These, with podcasts and some Twitter discussion, increased page views with a peak of 400 per month. Membership increased, and global 'attendance' was facilitated. Feelings and observations related to each book and the pandemic were noted in meeting reports. A survey of current and previous bookclub members carried out early in lockdown with the aim of determining the future direction of the bookclub revealed the continuing value of both literary and scientific experiences to members. The bookclub has engaged scientists and non-scientists in meaningful discussion about infectious disease. Reach is modest, but the resource is significant, with potential impact in education and engagement.

Visible light photocatalytic bismuth oxide coatings are effective at suppressing aquatic cyanobacteria and degrading free-floating genomic DNA.

Access to safe drinking water free from microbial pollution is an issue of global concern. The use of photocatalytic thin films in water treatment has focused on titanium dioxide, which requires UV-activation, proving a potential barrier to upscaling and implementation in the real world. Visible-light-activated photocatalytic thin films, such as bismuth oxide, have recently been shown to have antimicrobial properties. However, more understanding of the photocatalytic effect on the microbial population in water is required. Glass beads coated with bismuth oxide were incubated with either Microcystis aeruginosa, Anabaena sp. or free-floating genomic DNA. The presence of bismuth oxide-coated glass beads was able to rapidly stop a population of cyanobacteria from increasing. The coated beads were also able to degrade genomic DNA. Leachate from the beads showed no increase in toxicity against human liver cells. This data demonstrates the efficacy of bismuth oxide-coated glass beads for controlling potentially dangerous cyanobacterial populations, whilst potentially reducing the amount of free-floating genomic DNA (an essential issue in the face of antimicrobial resistance) - all of which should be essential considerations in emerging water treatment technologies.

The Removal of Meat Exudate and Escherichia coli from Stainless Steel and Titanium Surfaces with Irregular and Regular Linear Topographies.

Bacterial retention and organic fouling on meat preparation surfaces can be influenced by several factors. Surfaces with linear topographies and defined chemistries were used to determine how the orientation of the surface features affected cleaning efficacy. Fine polished (irregular linear) stainless steel (FPSS), titanium coated fine polished (irregular linear) stainless steel (TiFP), and topographically regular, linear titanium coated surfaces (RG) were fouled with Escherichia coli mixed with a meat exudate (which was utilised as a conditioning film). Surfaces were cleaned along or perpendicular to the linear features for one, five, or ten wipes. The bacteria were most easily removed from the titanium coated and regular featured surfaces. The direction of cleaning (along or perpendicular to the surface features) did not influence the amount of bacteria retained, but meat extract was more easily removed from the surfaces when cleaned in the direction along the linear surface features. Following ten cleans, there was no significant difference in the amount of cells or meat exudate retained on the surfaces cleaned in either direction. This study demonstrated that for the E. coli cells, the TiFP and RG surfaces were easiest to clean. However, the direction of the clean was important for the removal of the meat exudate from the surfaces.

Diverse surface properties reveal that substratum roughness affects fungal spore binding.

Binding to surfaces by fungal spores is a prerequisite to biofilm formation. The interactions of polytetrafluoroethylene (PTFE), glass, and silicon with three fungal spores, of differing shapes and sizes (Aspergillus niger 1957, Aspergillus niger 1988, and Aureobasidium pullulans), were investigated. A multifractal analysis was conducted to provide quantitative measures of density, dispersion, and clustering of spores on the surfaces. The PTFE, glass, and silicon surfaces presented a range of surface topographies and wettabilities. PTFE was the roughest and most non-wettable surface, whereas silicon was the opposite in terms of both these aspects. The A. niger species were more non-wettable than A. pullulans. Overall, A. niger 1957 attached in higher numbers to PTFE, whereas A. niger 1988 and A. pullulans bound in highest numbers to glass. The results of this work demonstrated that the overall substratum surface roughness influenced spore binding rather than the physicochemical or chemical properties of surfaces or spores.

Development of a rapid method for assessing the efficacy of antibacterial photocatalytic coatings.

Visible-light activated photocatalytic coatings may represent an attractive antimicrobial solution in domains such as food, beverage, pharmaceutical, biomedical and wastewater remediation. However, testing methods to determine the antibacterial effects of photocatalytic coatings are limited and require specialist expertise. This paper describes the development of a method that enables rapid screening of coatings for photocatalytic-antibacterial activity. Relying on the ability of viable microorganisms to reduce the dye resazurin from a blue to a pink colour, the method relates the time taken to detect this colour change with number of viable microorganisms. The antibacterial activity of two photocatalytic materials (bismuth oxide and titanium dioxide) were screened against two pathogenic organisms (Escherichia coli and Klebsiella pneumoniae) that represent potential target microorganisms using traditional testing and enumeration techniques (BS ISO 27447:2009) and the novel rapid method. Bismuth oxide showed excellent antibacterial activity under ambient visible light against E. coli, but was less effective against K. pneumoniae. The rapid method showed excellent agreement with existing tests in terms of number of viable cells recovered. Due to advantages such as low cost, high throughput, and less reliance on microbiological expertise, this method is recommended for researchers seeking an inexpensive first-stage screen for putative photocatalytic-antibacterial coatings.

Use of spherical particles to understand conidial attachment to surfaces using atomic force microscopy.

Binding of particles and spores to surfaces is a natural phenomenon which is a prerequisite for biofilm formation. Perpendicular force measurements were carried out using atomic force microscopy cantilevers modified with a polystyrene or glass sphere. The attachment of the spheres was tested against glass, PVAc, p(γ-MPSco-MMA), p(γ-MPS-co-LMA), PMMAsc, and silicon surfaces. The polystyrene spheres demonstrated less varied force and strength of attachment measurement to the surfaces than the glass spheres. The force of attachment of the polystyrene spheres was also influenced by mobility of the co-polymer surfaces. Surface wettability did not affect the force of polystyrene or glass sphere attachment. The force measurements of the non-biological spheres were similar to those seen in biological systems with fungal conidia, and this was due to their size, shape, and binding energies. The use of non-biological systems may present an insight into understanding the fundamentals of more complex biological processes.

Biofilm Control Strategies: Engaging with the Public.

There are few peer-reviewed publications about public engagement with science that are written by microbiologists; those that exist tend to be a narrative of an event rather than a hypothesis-driven investigation. However, it is relatively easy for experienced scientists to use a scientific method in their approach to public engagement. This short communication describes three public engagement activities hosted by the authors, focused on biofilm control: hand hygiene, plaque control and an externally applied antimicrobial coating. In each case, audience engagement was assessed using quantitative and/or qualitative methods. A critical evaluation of the findings enabled the construction of a public engagement 'tick list' for future events that would enable a hypothesis-driven approach with more effective communication activities and more robust evaluation.

Methylcellulose Hydrogel with Melissa officinalis Essential Oil as a Potential Treatment for Oral Candidiasis.

Candida spp. are the most prevalent fungi of the human microbiota and are opportunistic pathogens that can cause oral candidiasis. Management of such infections is limited due to the low number of antifungal drugs available, their relatively high toxicity and the emergence of antifungal resistance. Therefore, much interest in the antimicrobial potential of natural compounds has recently been evident. The use of hydrogels in the delivery of biocides has been explored due to their biocompatibility, ease with drug encapsulation, and due to their potential to confer mechanical and structural properties similar to biological tissue. Methylcellulose hydrogels (10% (w/v)) with 1% (v/v) and 2% (v/v) Melissa officinalis oil were synthesised. The rheological properties and gelation time of the hydrogels were evaluated. Antimicrobial action, the antifungal potential and ability to displace Candida were determined. Rheological tests revealed that the hydrogel jellified in three minutes at 37 °C. Loaded hydrogels successfully inhibited Candida albicans growth as evident by zone of inhibition and time-kill assays. A significant reduction in retained C. albicans was demonstrated with the hydrogel at 2% Melissa officinalis concentration. This work demonstrated that an essential oil-loaded hydrogel had the potential to provide a novel antimicrobial therapy for the treatment of oral candidiasis.

Raising awareness of antimicrobial resistance among the general public in the UK: the role of public engagement activities.

In response to the accepted risk of emerging antimicrobial resistance, many organizations and institutions have developed and delivered events and activities designed to raise awareness of the issue and to change the behaviour of the intended audience. However, few of these events for a general public audience are documented or able to be sourced by those who might wish to repeat, adapt or modify, particularly those events that are successful. 'Insider knowledge' appears to be the best search tool. Moreover, evaluation of the success or impact of the event is rarely published. It would be useful if there were a 'hub' where descriptions of such activities could be deposited, enabling the building of a significant resource with real academic value.

Zeolite-embedded silver extends antimicrobial activity of dental acrylics.

The insertion of prosthetic devices into the oral cavity affects the oral microflora and results in accumulation of microorganisms on the prosthetic surface. Such fouling of denture surfaces can lead to a number of oral diseases and consequently to the replacement of the denture. Here, we report the post-synthesis introduction of silver in zeolite-loaded dental acrylic (DAZ) resins that does not influence the mechanical or aesthetic properties of the DA resins, and provides them with a long-term antimicrobial activity. Na-FAU zeolite (2 wt%) was incorporated into DA resin, which was conventionally processed and cut into 10 mm × 20 mm × 3 mm coupons. The Na+ in the zeolite was then exchanged with Ag+ via immersion of the DAZ coupons in 0.01 M AgNO3 solution to obtain DAZ/Ag-treated coupons used in antimicrobial tests. Antimicrobial tests showed that the DAZ/Ag-treated coupons were active against Candida albicans (a reference and a clinically relevant strain), Streptococcus mutans and Fusobacterium nucleatum. Ag leaching tests on the Ag-charged coupons at 1, 2, 3, 4, 7, 14, 30 and 45 days of incubation in distilled water at 37 °C, indicated sustained release of silver. Antimicrobial tests using a reference Candida albicans strain showed that the leached coupons retained antimicrobial activity after 45 days immersion in distilled water, but, after 60 days incubation no antimicrobial activity was observed. Cytotoxicity assay results indicated that the DAZ/Ag-treated coupons showed no additional cytotoxicity compared to neat dental acrylic coupons.