Microbial Biofilms Research Articles

Microbial communities on microplastics from seawater and mussels: Insights from the northern Adriatic Sea

Microplastics, synthetic solid particles of different sizes (< 5 mm), pose a major challenge to marine ecosystems. Introducing microplastics into the marine environment leads to the formation of complex microbial communities, a topic of growing interest in environmental research. For this study, we selected an area in the northern Adriatic Sea, less affected by human activities, to understand how pristine environmental conditions influence microbial colonization of microplastics. Samples of coastal seawater and Mediterranean mussels (Mytilus galloprovincialis) were collected in a mussel farm near Debeli rtič of the Slovenian coast. Microplastics were isolated, visually and chemically analyzed and DNA was extracted for metagenomics. In the marine water column, 12.7 microplastics per m3 water column and 0.58 microplastics per individual mussel were found. Sufficient DNA was available to analyze six particles, five originating from seawater, and one from a mussel. This was the first-ever sequenced microplastic particle from a mussel. Genera of Pseudomonas and Serratia were identified in all samples. In one of the samples, the most abundant was a marine genus Pseudoalteromonas, while in another sample Campylobacter was present with >30 % abundance. The microbiomes of the mussel- and seawater-isolated particles were similar, suggesting a common microbial colonization pattern, which may have implications for the transfer of microplastic-associated microbes, including potential pathogens, through the food web to the consumers. Microplastic pollution is a complex issue requiring further research, especially regarding microbial biofilms, pathogen colonization and the potential of pathogen transmission via microplastic particles. Our findings enhance the understanding of microplastic pollution in the Adriatic Sea and stress the necessity for comprehensive strategies to mitigate the impact on marine ecosystems.

Antifungal and antibiofilm activities of flavonoids against Candida albicans: Focus on 3,2′-dihydroxyflavone as a potential therapeutic agent

Effective management of microbial biofilms holds significance within food and medical environments. Candida albicans, an opportunistic fungus, forms mucosal biofilms closely linked to candidiasis and drug-resistant infections due to their drug tolerance. Morphologic change from yeast to filamentous cells is a key virulence factor and a prerequisite for biofilm development. This study investigated the anti-fungal and antibiofilm activities of 20 flavonoids against C. albicans. With their known antioxidant capabilities, flavonoids hold promise in combating infections associated with biofilms. Among them, flavone and its derivatives exhibited moderate antifungal activity, 3,2′-dihydroxyflavone (3,2′-DHF) at 1 μg/mL exhibited strong antibiofilm activity (MIC 50 μg/mL). In addition, 3,2′-DHF dramatically inhibited cell aggregation and germ tube/hyphae formation. Transcriptomic analyses revealed that flavone and 3,2′-DHF behaved differently, as 3,2′-DHF downregulated the expressions of germ tube/hyphae-forming and biofilm-related genes (ECE1, HWP1, TEC1, and UME6) but upregulated the biofilm/hyphal regulators (CHK1, IFD6, UCF1, and YWP1). Tests evaluating toxicity with plant and nematode models revealed that flavone and 3,2′-DHF exhibited mild toxicity. Current results indicate that hydroxylated flavone derivatives can enhance anti-fungal and antibiofilm activities and provide a source of potential anti-fungal agents against drug-resistant C. albicans.

Biofilm marker discovery with cloud-based dockerized metagenomics analysis of microbial communities.

In an environment, microbes often work in communities to achieve most of their essential functions, including the production of essential nutrients. Microbial biofilms are communities of microbes that attach to a nonliving or living surface by embedding themselves into a self-secreted matrix of extracellular polymeric substances. These communities work together to enhance their colonization of surfaces, produce essential nutrients, and achieve their essential functions for growth and survival. They often consist of diverse microbes including bacteria, viruses, and fungi. Biofilms play a critical role in influencing plant phenotypes and human microbial infections. Understanding how these biofilms impact plant health, human health, and the environment is important for analyzing genotype-phenotype-driven rule-of-life functions. Such fundamental knowledge can be used to precisely control the growth of biofilms on a given surface. Metagenomics is a powerful tool for analyzing biofilm genomes through function-based gene and protein sequence identification (functional metagenomics) and sequence-based function identification (sequence metagenomics). Metagenomic sequencing enables a comprehensive sampling of all genes in all organisms present within a biofilm sample. However, the complexity of biofilm metagenomic study warrants the increasing need to follow the Findability, Accessibility, Interoperability, and Reusable (FAIR) Guiding Principles for scientific data management. This will ensure that scientific findings can be more easily validated by the research community. This study proposes a dockerized, self-learning bioinformatics workflow to increase the community adoption of metagenomics toolkits in a metagenomics and meta-transcriptomics investigation. Our biofilm metagenomics workflow self-learning module includes integrated learning resources with an interactive dockerized workflow. This module will allow learners to analyze resources that are beneficial for aggregating knowledge about biofilm marker genes, proteins, and metabolic pathways as they define the composition of specific microbial communities. Cloud and dockerized technology can allow novice learners-even those with minimal knowledge in computer science-to use complicated bioinformatics tools. Our cloud-based, dockerized workflow splits biofilm microbiome metagenomics analyses into four easy-to-follow submodules. A variety of tools are built into each submodule. As students navigate these submodules, they learn about each tool used to accomplish the task. The downstream analysis is conducted using processed data obtained from online resources or raw data processed via Nextflow pipelines. This analysis takes place within Vertex AI's Jupyter notebook instance with R and Python kernels. Subsequently, results are stored and visualized in Google Cloud storage buckets, alleviating the computational burden on local resources. The result is a comprehensive tutorial that guides bioinformaticians of any skill level through the entire workflow. It enables them to comprehend and implement the necessary processes involved in this integrated workflow from start to finish. This manuscript describes the development of a resource module that is part of a learning platform named "NIGMS Sandbox for Cloud-based Learning" https://github.com/NIGMS/NIGMS-Sandbox. The overall genesis of the Sandbox is described in the editorial NIGMS Sandbox [1] at the beginning of this Supplement. This module delivers learning materials on the analysis of bulk and single-cell ATAC-seq data in an interactive format that uses appropriate cloud resources for data access and analyses.

Inhibition of Microbial Growth and Biofilm Formation in Pure and Mixed Bacterial Samples.

Hydraulic fracturing, or fracking, requires large amounts of water to extract fossil fuel from rock formations. As a result of hydraulic fracturing, the briny wastewater, often termed back-produced fracturing or fracking water (FW), is pumped into holding ponds. One of the biggest challenges with produced water management is controlling microbial activity that could reduce the pond water's reusable layer and pose a significant environmental hazard. This study focuses on the characterization of back-produced water that has been hydraulically fractured using chemical and biological analysis and the development of a high-throughput screening method to evaluate and predict the antimicrobial effect of four naturally and commercially available acidic inhibitors (edetic acid, boric acid, tannic acid, and lactic acid) on the growth of the FW microbiome. Liquid cultures and biofilms of two laboratory model strains, the vegetative Escherichia coli MG1655, and the spore-forming Bacillus atrophaeus (also known as Bacillus globigii, BG) bacteria, were used as reference microorganisms. Planktonic bacteria in FW were more sensitive to antimicrobials than sessile bacteria in biofilms. Spore-forming BG bacteria exhibited more sensitivity to acidic inhibitors than the vegetative E. coli cells. Organic acids were the most effective bacterial growth inhibitors in liquid culture and biofilm.

Antithrombotic and Antimicrobial Potential of S-Nitroso-1-Adamantanethiol-Impregnated Extracorporeal Circuit.

This study presents the utilization of a novel, highly lipophilic nitric oxide (NO) donor molecule, S-nitroso-1-adamantanethiol (SNAT), for developing an NO-emitting polymer surface aimed at preventing thrombus formation and bacterial infection in extracorporeal circuits (ECCs). S-nitroso-1-adamantanethiol, a tertiary nitrosothiol-bearing adamantane species, was synthesized, characterized, and used to impregnate polyvinyl chloride (PVC) tubing for subsequent in vivo evaluation. The impregnation process with SNAT preserved the original mechanical strength of the PVC. In vitro assessments revealed sustained NO release from the SNAT-impregnated PVC tubing (iSNAT), surpassing or matching endothelial NO release levels for up to 42 days. The initial NO release remained stable even after 1 year of storage at -20°C. The compatibility of iSNAT with various sterilization techniques (OPA Plus, hydrogen peroxide, EtO) was tested. Acute in vivo experiments in a rabbit model demonstrated significantly reduced thrombus formation in iSNAT ECCs compared with controls, indicating the feasibility of iSNAT to mitigate coagulation system activation and potentially eliminate the need for systemic anticoagulation. Moreover, iSNAT showed substantial inhibition of microbial biofilm formation, highlighting its dual functionality. These findings underscore the promising utility of iSNAT for long-term ECC applications, offering a multifaceted approach to enhancing biocompatibility and minimizing complications.

The synergistic effect of photodynamic and sonodynamic inactivation against Candida albicans biofilm.

Candida albicans biofilm can cause diseases that are resistant to conventional antifungal agents. Photodynamic (PDI), sonodynamic (SDI), and sonophotodynamic (SPDI) inactivation have arisen as promising antimicrobial strategies. This study evaluated these treatments mediated by curcumin against C. albicans biofilms. For this, C. albicans biofilms were submitted to PDI, SDI, or SPDI with different light and ultrasound doses, then, the viability assay was performed to measure the effectiveness. Finally, a mathematical model was suggested to fit acquired experimental data and understand the synergistic effect of light and ultrasound in different conditions. The results showed that SPDI, PDI, and SDI reduced the viability in 6 ± 1; 1 ± 1; and 2 ± 1 log, respectively, using light at 60 J/cm2, ultrasound at 3 W/cm2, and 80 μM of curcumin. The viability reduction was proportional to the ultrasound and light doses delivered. These results encourage the use of SPDI for the control of microbial biofilm.

The influence of different methods of decontamination of microbial biofilms formed on eggshells

According to "food legislation" requirements, all eggs entering the production of egg products must be disinfected. Therefore, developing technologies for decontaminating chicken eggs before use for food purposes is a promising work direction in chicken egg production and storage. This research aimed to identify the microbiota of chicken eggs with varying degrees of shell contamination and determine the influence of different methods of decontaminating microbial biofilms formed on eggshells. It was set up that the quantitative content of microorganisms on the surface of chicken eggs ranged from 103 CFU to 106 CFU/ml of washing and depended on the contamination of the shell with droppings. Lactobacillus spp., Bacillus spp., Corynebacterium, Staphylococcus were among the genera of bacteria that prevailed on the clean chicken shell, which were isolated in 30-50% of cases, and gram-negative microbiota was practically absent. The constant release of gram-positive bacteria is noted on the contaminated eggshell, and the frequency of identification of gram-negative microbiota of the Enterobacteriaceae genus and non-fermenting genera Pseudomonas and Psychrobacter increases. That is, the microbial scape of the microbiota of the chicken shell depends on its cleanliness, and the presence of a dirty surface increases the frequency of allocation of the resident microflora of the gastrointestinal tract. It was found that the working solution of the disinfectant Vircon S destroyed planktonic bacteria applied to the eggshell in an average of 2 minutes of exposure, stabilised water ozone for 1 minute, gaseous ozone for 3 minutes, and the action of ultraviolet rays with a length of 253.7 nm for 25-30 min. At the same time, using these disinfection methods on bacteria formed in a biofilm on the eggshell did not cause a bactericidal action during this time. To significantly reduce bacteria in the biofilm using these methods, it is necessary to increase the exposure time of the biocide by 2-3 times. Therefore, the complex structure of the eggshell and the multi-layered matrix of biofilms provide better protection for bacteria against the influence of the investigated disinfection methods.

Design of a two functional permeable reactive barrier for synergistic enzymatic and microbial bioremediation of phenol-contaminated waters: laboratory column evaluation

The present study aimed to develop a system using a combination of enzymatic and microbial degradation techniques for removing phenol from contaminated water. In our prior research, the HRP enzyme extracted from horseradish roots was utilized within a core-shell microcapsule to reduce phenolic shock, serving as a monolayer column. To complete the phenol removal process, a second column containing degrading microorganisms was added to the last column in this research. Phenol-degrading bacteria were isolated from different microbial sources on a phenolic base medium. Additionally, encapsulated calcium peroxide nanoparticles were used to provide dissolved oxygen for the microbial population. Results showed that the both isolated strains, WC1 and CC1, were able to completely remove phenol from the contaminated influent water the range within 5 to 7 days, respectively. Molecular identification showed 99.8% similarity for WC1 isolate to Stenotrophomonas rizophila strain e-p10 and 99.9% similarity for CC1 isolate to Bacillus cereus strain IAM 12,605. The results also indicated that columns using activated sludge as a microbial source had the highest removal rate, with the microbial biofilm completely removing 100% of the 100 mg/L phenol concentration in contaminated influent water after 40 days. Finally, the concurrent use of core-shell microcapsules containing enzymes and capsules containing Stenotrophomonas sp. WC1 strain in two continuous column reactors was able to completely remove phenol from polluted water with a concentration of 500 mg/L for a period of 20 days. The results suggest that a combination of enzymatic and microbial degrading systems can be used as a new system to remove phenol from polluted streams with higher concentrations of phenol by eliminating the shock of phenol on the microbial population.

Global challenges and microbial biofilms: Identification of priority questions in biofilm research, innovation and policy

Priority question exercises are increasingly used to frame and set future research, innovation and development agendas. They can provide an important bridge between the discoveries, data and outputs generated by researchers, and the information required by policy makers and funders. Microbial biofilms present huge scientific, societal and economic opportunities and challenges. In order to identify key priorities that will help to advance the field, here we review questions from a pool submitted by the international biofilm research community and from practitioners working across industry, the environment and medicine. To avoid bias we used computational approaches to group questions and manage a voting and selection process. The outcome of the exercise is a set of 78 unique questions, categorized in six themes: (i) Biofilm control, disruption, prevention, management, treatment (13 questions); (ii) Resistance, persistence, tolerance, role of aggregation, immune interaction, relevance to infection (10 questions); (iii) Model systems, standards, regulatory, policy education, interdisciplinary approaches (15 questions); (iv) Polymicrobial, interactions, ecology, microbiome, phage (13 questions); (v) Clinical focus, chronic infection, detection, diagnostics (13 questions); and (vi) Matrix, lipids, capsule, metabolism, development, physiology, ecology, evolution environment, microbiome, community engineering (14 questions). The questions presented are intended to highlight opportunities, stimulate discussion and provide focus for researchers, funders and policy makers, informing future research, innovation and development strategy for biofilms and microbial communities.

Three-Dimensional-Printed Modular Titanium Alloy Plates for Osteosynthesis of the Jawbone.

The titanium-aluminum-vanadium alloy (Ti-6Al-4V) is frequently used in implantology due to its biocompatibility. The use of 3D printing enables the mechanical modification of implant structures and the adaptation of their shape to the specific needs of individual patients. The titanium alloy plates were designed using the 3D CAD method and printed using a 3D SLM printer. Qualitative tests were performed on the material surface using a microcomputed tomography scanner. The cytotoxicity of the modular titanium plates was investigated using the MTT assay on the L929 cell line and in direct contact with Balb/3T3 cells. Cell adhesion to the material surface was evaluated with hFOB1.19 human osteoblasts. Microbial biofilm formation was investigated on strains of Lactobacillus rhamnosus, Staphylococcus epidermidis, Streptococcus mutans and Candida albicans using the TTC test and scanning electron microscopy (SEM). The surface analysis showed the hydrophobic nature of the implant. The study showed that the titanium plates had no cytotoxic properties. In addition, the material surface showed favorable properties for osteoblast adhesion. Among the microorganisms tested, the strains of S. mutans and S. epidermidis showed the highest adhesion capacity to the plate surface, while the fungus C. albicans showed the lowest adhesion capacity. The manufactured modular plates have properties that are advantageous for the implantation and reduction in selected forms of microbial biofilm. Three-dimensional-printed modular titanium plates were investigated in this study and revealed the potential clinical application of this type of materials, regarding lack of cytotoxicity, high adhesion properties for osteoblasts and reduction in biofilm formation. The 3D CAD method allows us to personalise the shape of implants for individual patients.

Escherichia coli exopolysaccharides disrupt Pseudomonas aeruginosa biofilm and increase its antibiotic susceptibility

Pseudomonas aeruginosa (P. aeruginosa) is a major pathogen that causes infectious diseases. It has high tendency to form biofilms, resulting in the failure of traditional antibiotic therapies. Inspired by the phenomenon that co-culture of Escherichia coli (E. coli) and P. aeruginosa leads to a biofilm reduction, we reveal that E. coli exopolysaccharides (EPS) can disrupt P. aeruginosa biofilm and increase its antibiotic susceptibility. The results show that E. coli EPS effectively inhibit biofilm formation and disrupt mature biofilms in P. aeruginosa, Staphylococcus aureus, and E. coli itself. The maximal inhibition and disruption rates against P. aeruginosa biofilm are 40 % and 47 %, respectively. Based on the biofilm-disrupting ability of E. coli EPS, we develop an E. coli EPS/antibiotic combining strategy for the treatment of P. aeruginosa biofilms. The combination with E. coli EPS increases the antibacterial efficiency of tobramycin against P. aeruginosa biofilms in vitro and in vivo. This study provides a promising strategy for treating biofilm infections. Statement of significanceBiofilm formation is a leading cause of chronic infections. It blocks antibiotics, increases antibiotic-tolerance, and aids in immune evasion, thus representing a great challenge in clinic. This study proposes a promising approach to combat pathogenic Pseudomonas aeruginosa (P. aeruginosa) biofilms by combining Escherichia coli exopolysaccharides with antibiotics. This strategy shows high efficiency in different P. aeruginosa stains, including two laboratory strains, PAO1 and ATCC 10145, as well as a clinically acquired carbapenem-resistant strain. In addition, in vivo experiments have shown that this approach is effective against implanted P. aeruginosa biofilms and can prevent systemic inflammation in mice. This strategy offers new possibilities to address the clinical failure of conventional antibiotic therapies for microbial biofilms.

Microbiological and Imaging-Based Evaluations of Photodynamic Therapy Combined with Er:YAG Laser Therapy in the In Vitro Decontamination of Titanium and Zirconia Surfaces.

The oral cavity's soft and hard tissues create a conducive environment for microbial proliferation and biofilm development, facilitating the colonization of prosthodontic and implant materials such as titanium (Ti) and zirconia (Zr). This study aimed to compare the efficacy of conventional decontamination methodologies (i.e., chemical and mechanical, using 0.12% digluconate chlorhexidine (CHX) solution-treatment and airflow) to adjunctive laser-based interventions on Ti and Zr substrates inoculated with Staphylococcus (S.) aureus ATCC 25923. Additionally, this investigation sought to elucidate the impact of these treatments on temperature variations and surface integrity, analyzing the laser irradiation effects on these prevalent dental materials. Experimental configurations were delineated for both Ti and Zr samples across four groups: (1) a conventional treatment group (CV); (2) a photodynamic therapy group (PDT); (3) an Er:YAG laser treatment group (Er); (4) a combined PDT and Er:YAG treatment group (PDTEr). Also, a negative control group (C) that received no treatment was considered. The decontamination of the inoculated disc samples was evaluated by quantifying the microbial colonies in colony-forming units per milliliter (CFU/mL). Temperature variations on the surface of the samples were determined during laser treatments. Surface modifications were investigated using scanning electron microscopy (SEM) and optical coherence tomography (OCT). For statistical analysis, Fisher 95% confidence intervals, Hsu's MCB method, and the Kruskal-Wallis test were applied. With regard to the 105 CFU/mL of the negative control group, results indicated average values equal for each study group to (1) 2.66 CFU/mL for Ti and 2 CFU/mL for Zr for the CV group; (2) 0.33 CFU/mL for Ti and 1 CFU/mL for Zr for the PDT group; (3) 1.25 CFU/mL for Ti and 0 CFU/mL for Zr for the Er group; (4), and 0 CFU/mL for both Ti and Zr for the PDTEr group. Therefore, the combined PDT and Er:YAG treatment (PDTEr) and the singular PDT modality outperformed conventional decontamination methods in eradicating S. aureus biofilms from both Ti and Zr surfaces. Notably, the PDTEr regime achieved a comprehensive elimination of microbial colonies on treated substrates. Surface examination employing OCT demonstrated discernible alterations in the surface morphology of samples subjected to Er:YAG and combined PDT and Er:YAG treatments. Temperature checks during treatments showed no major changes, suggesting the applied laser methods are safe. In conclusion, PDTEr and PDT eliminated bacteria more effectively, but Zr surfaces were more resilient, making them better for microbe-controlling applications. Also, the study demonstrated that the (less costly but lower resolution) OCT method can replace SEM for such investigations.

Torosites: A New Microbially Mediated Speleothem from Sistema los Toros, Nuevo Léon, Mexico

Although several kinds of speleothems are known to grow with pendant morphology (i.e., helictites, pool fingers, and stalactites), we describe here a new form found in Sistema Los Toros, Nuevo Léon, Mexico, which we propose to call torosites. A laminated, bladed, spar crust grew beneath remnants of a stromatolitic micritic crust and extended mostly downward as irregular finger-like protrusions (torosites) that are 2–3 mm wide and 2–3 cm long. Although mainly pendants, the individual torosites are quite irregular with growth sideways and even upward in places. The torosites thicken and thin, like knuckles on a finger, but maintain a relatively uniform diameter. Laminations in the bladed spar and protrusions are defined by micritic intervals with minor intermixed detrital grains (clay, quartz, and carbonate silt) and rare, ropy biofilm. Bladed-spar crystals nucleate off thicker detrital layers, but they extend through thinner lamina. The torosites lack the central canal of helictites and most stalactites. Unlike pool fingers and stalactites, torosites only grow on the end of the speleothem, not on the sides. We hypothesize that the torosites grew from dripping water at their ends. Microbial biofilm communities colonized the growth surface, probably during drier conditions, forming the micritic layers. We speculate that the microbial mat likely caused the irregular sideways growth, but we cannot identify how on these fossil forms. Torosites are unique and add to the growing list of known microbially mediated speleothems.

Study of the Resistance of Staphylococcus aureus Biofilm, Biofilm-Detached Cells, and Planktonic Cells to Microencapsulated Carvacrol Used Alone or Combined with Low-pH Treatment.

Microbial biofilms pose severe problems in the medical field and food industry, as they are the cause of many serious infections and food-borne diseases. The extreme biofilms' resistance to conventional anti-microbial treatments presents a major challenge to their elimination. In this study, the difference in resistance between Staphylococcus aureus DSMZ 12463 biofilms, biofilm-detached cells, and planktonic cells against microcapsules containing carvacrol was assessed. The antimicrobial/antibiofilm activity of low pH disinfection medium containing the microencapsulated carvacrol was also studied. In addition, the effect of low pH on the in vitro carvacrol release from microcapsules was investigated. The minimum inhibitory concentration of microencapsulated carvacrol was 0.625 mg mL-1. The results showed that biofilms exhibited greater resistance to microencapsulated carvacrol than the biofilm-detached cells and planktonic cells. Low pH treatment alone, by hydrochloric acid addition, showed no bactericidal effect on any of the three states of S. aureus strain. However, microencapsulated carvacrol was able to significantly reduce the planktonic cells and biofilm-detached cells below the detection limit (no bacterial counts), and the biofilm by approximatively 3 log CFU mL-1. In addition, results showed that microencapsulated carvacrol combined with low pH treatment reduced biofilm by more than 5 log CFU mL-1. Thus, the use of microencapsulated carvacrol in acidic environment could be a promising approach to combat biofilms from abiotic surfaces.

Metagenomic and paleopathological analyses of a historic documented collection explore ancient dental calculus as a diagnostic tool

Dental calculus is a microbial biofilm that contains biomolecules from oral commensals and pathogens, including those potentially related to cause of death (CoD). To assess the utility of calculus as a diagnostically informative substrate, in conjunction with paleopathological analysis, calculus samples from 39 individuals in the Smithsonian Institution’s Robert J. Terry Collection with CoDs of either syphilis or tuberculosis were assessed via shotgun metagenomic sequencing for the presence of Treponema pallidum subsp. pallidum and Mycobacterium tuberculosis complex (MTBC) DNA. Paleopathological analysis revealed that frequencies of skeletal lesions associated with these diseases were partially inconsistent with diagnostic criteria. Although recovery of T. p. pallidum DNA from individuals with a syphilis CoD was elusive, MTBC DNA was identified in at least one individual with a tuberculosis CoD. The authenticity of MTBC DNA was confirmed using targeted quantitative PCR assays, MTBC genome enrichment, and in silico bioinformatic analyses; however, the lineage of the MTBC strain present could not be determined. Overall, our study highlights the utility of dental calculus for molecular detection of tuberculosis in the archaeological record and underscores the effect of museum preparation techniques and extensive handling on pathogen DNA preservation in skeletal collections.

Natural Bioactive Compounds in the Management of Periodontal Diseases: A Comprehensive Review.

Periodontal diseases, chronic inflammatory conditions affecting oral health, are primarily driven by microbial plaque biofilm and the body's inflammatory response, leading to tissue damage and potential tooth loss. These diseases have significant physical, psychological, social, and economic impacts, necessitating effective management strategies that include early diagnosis, comprehensive treatment, and innovative therapeutic approaches. Recent advancements in biomanufacturing have facilitated the development of natural bioactive compounds, such as polyphenols, terpenoids, alkaloids, saponins, and peptides, which exhibit antimicrobial, anti-inflammatory, and tissue regenerative properties. This review explores the biomanufacturing processes-microbial fermentation, plant cell cultures, and enzymatic synthesis-and their roles in producing these bioactive compounds for managing periodontal diseases. The integration of these natural compounds into periodontal therapy offers promising alternatives to traditional treatments, potentially overcoming issues like antibiotic resistance and the disruption of the natural microbiota, thereby improving patient outcomes.

Antimicrobial Efficacy of Photocaged β‐lapachone in Bacillus subtilis Biofilms

With the rise of antibiotic resistance within clinical settings, combating the growth of microbial biofilms presents a unique challenge. Biofilm‐inhabiting bacteria are embedded within a self‐produced, protective matrix, which can reduce the efficacy of treatment. The naturally derived product β‐lapachone is an appealing therapeutic agent that has been reported to inhibit biofilm growth. However, its off‐target toxicity and poor metabolic stability pose a significant hurdle for its application in vivo. Using a photo‐pharmacological approach via a coumarin‐based photocage, the reactivity of β‐lapachone can be tuned so it only becomes active once the photocage is removed. Here we report both the photo‐uncaging efficiency and the effective inhibition concentration of photocaged β‐lapachone within model Bacillus subtilis biofilms. Additionally, the mechanism of action is analyzed with results supporting catalase inhibition. This novel light‐activatable anti‐microbial has potential applications in medical settings to inhibit biofilm growth and provide synergistic treatment with traditional antibiotics.

Real-time biofilm detection techniques: advances and applications.

Microbial biofilms, complex assemblies enveloped in extracellular matrices, are significant contributors to various infections. Traditional in vitro biofilm characterization methods, though informative, often disrupt the biofilm structure. The need to address biofilm-related infections urgently emphasizes the importance of continuous monitoring and timely interventions. This review provides a focused examination of advancements in real-time biofilm detection techniques, specifically in electrochemical, optical and mechanical systems. The potential applications of real-time detection in managing and monitoring biofilm growth in industrial settings, preventing medical infections, comprehending biofilm dynamics and evaluating control strategies highlight the necessity for it. Crucially, the review emphasizes the importance of evaluating these methods for their accuracy and reliability in real-time biofilm detection, offering valuable insights for precise interventions across various applications.

New Generation of Osteoinductive and Antimicrobial Polycaprolactone-Based Scaffolds in Bone Tissue Engineering: A Review.

With respect to other fields, bone tissue engineering has significantly expanded in recent years, leading not only to relevant advances in biomedical applications but also to innovative perspectives. Polycaprolactone (PCL), produced in the beginning of the 1930s, is a biocompatible and biodegradable polymer. Due to its mechanical and physicochemical features, as well as being easily shapeable, PCL-based constructs can be produced with different shapes and degradation kinetics. Moreover, due to various development processes, PCL can be made as 3D scaffolds or fibres for bone tissue regeneration applications. This outstanding biopolymer is versatile because it can be modified by adding agents with antimicrobial properties, not only antibiotics/antifungals, but also metal ions or natural compounds. In addition, to ameliorate its osteoproliferative features, it can be blended with calcium phosphates. This review is an overview of the current state of our recent investigation into PCL modifications designed to impair microbial adhesive capability and, in parallel, to allow eukaryotic cell viability and integration, in comparison with previous reviews and excellent research papers. Our recent results demonstrated that the developed 3D constructs had a high interconnected porosity, and the addition of biphasic calcium phosphate improved human cell attachment and proliferation. The incorporation of alternative antimicrobials-for instance, silver and essential oils-at tuneable concentrations counteracted microbial growth and biofilm formation, without affecting eukaryotic cells' viability. Notably, this challenging research area needs the multidisciplinary work of material scientists, biologists, and orthopaedic surgeons to determine the most suitable modifications on biomaterials to design favourable 3D scaffolds based on PCL for the targeted healing of damaged bone tissue.

Growth of electroautotrophic microorganisms using hydrovoltaic energy through natural water evaporation

It has been previously shown that devices based on microbial biofilms can generate hydrovoltaic energy from water evaporation. However, the potential of hydrovoltaic energy as an energy source for microbial growth has remained unexplored. Here, we show that the electroautotrophic bacterium Rhodopseudomonas palustris can directly utilize evaporation-induced hydrovoltaic electrons for growth within biofilms through extracellular electron uptake, with a strong reliance on carbon fixation coupled with nitrate reduction. We obtained similar results with two other electroautotrophic bacterial species. Although the energy conversion efficiency for microbial growth based on hydrovoltaic energy is low compared to other processes such as photosynthesis, we hypothesize that hydrovoltaic energy may potentially contribute to microbial survival and growth in energy-limited environments, given the ubiquity of microbial biofilms and water evaporation conditions.