Natural Microbial Communities Can Be Manipulated by Artificially Constructed Biofilms

Engineered Microorganisms for Advancing Tumor Therapy

Engineered microorganisms have attracted significant interest as a unique therapeutic platform in tumor treatment. Compared with conventional cancer treatment strategies, engineering microorganism-based systems provide various distinct advantages, such as the intrinsic capability in targeting tumors, their inherent immunogenicity, in situ production of antitumor agents, and multiple synergistic functions to fight against tumors. Herein, the design, preparation, and application of the engineered microorganisms for advanced tumor therapy are thoroughly reviewed. This review presents a comprehensive survey of innovative tumor therapeutic strategies based on a series of representative engineered microorganisms, including bacteria, viruses, microalgae, and fungi. Specifically, it offers extensive analyses of the design principles, engineering strategies, and tumor therapeutic mechanisms, as well as the advantages and limitations of different engineered microorganism-based systems. Finally, the current challenges and future research prospects in this field, which can inspire new ideas for the design of creative tumor therapy paradigms utilizing engineered microorganisms and facilitate their clinical applications, are discussed.

Study of Anticorrosion and Antifouling Properties of a Cu-Doped TiO2 Coating Fabricated via Micro-Arc Oxidation

As a promising material for petroleum industrial applications, titanium (Ti) and its alloys receive wide attention due to their outstanding physicochemical properties. However, the harsh industrial environment requires an antifouling surface with a desired corrosion resistance for Ti and its alloys. In order to achieve the desired antifouling properties, micro-arc oxidation (MAO) was used to prepare a Cu-doped TiO2 coating. The microstructure of the Cu-doped TiO2 coating was investigated by TF-XRD, SEM, and other characterization techniques, and its antifouling and anticorrosion properties were also tested. The results show the effects of the incorporation of Cu (~1.73 wt.%) into TiO2 to form a Cu-doped TiO2, namely, a Ti-Cu coating. The porosity (~4.8%) and average pore size (~0.42 μm) of the Ti-Cu coating are smaller than the porosity (~5.6%) and average pore size (~0.66 μm) of Ti-blank coating. In addition, there is a significant reduction in the amount of SRB adhesion on the Ti-Cu coating compared to the Ti-blank coating under the same conditions, while there is little difference in corrosion resistance between the two coatings. There, the addition of copper helps to improve the fouling resistance of TiO2 coatings without compromising their corrosion resistance. Our work provides a practical method to improve the antifouling function of metallic Ti substrates, which could promote the application of Ti in the petroleum industry.

Antibiofilm Effect of Curcumin on Saccharomyces boulardii during Beer Fermentation and Bottle Aging

In a prior study, we elucidated the biofilm formation of Saccharomyces boulardii on glass surfaces during beer bottle aging. Here, we supplemented brewing wort with curcumin at 25 μg/mL concentration to mitigate S. boulardii biofilm and enhance beer's functional and sensory attributes. An assessment encompassing biofilm growth and development, fermentation performance, FLO gene expression, yeast ultrastructure, bioactive content, and consumer acceptance of the beer was conducted throughout fermentation and aging. Crystal violet (CV) and XTT reduction assays unveiled a significant (p < 0.05) reduction in biofilm formation and development. Fluorescent staining (FITC-conA) and imaging with confocal laser scanning microscopy provided visual evidence regarding reduced exopolysaccharide content and biofilm thickness. Transcriptional analyses showed that key adhesins (FLO1, FLO5, FLO9, and FLO10) were downregulated, whereas FLO11 expression remained relatively stable. Although there were initial variations in terms of yeast population and fermentation performance, by day 6, the number of S. boulardii in the test group had almost reached the level of the control group (8.3 log CFU/mL) and remained stable thereafter. The supplementation of brewing wort with curcumin led to a significant (p < 0.05) increase in the beer's total phenolic and flavonoid content. In conclusion, curcumin shows promising potential for use as an additive in beer, offering potential antibiofilm and health benefits without compromising the beer's overall characteristics.

Manipulating Bacterial Biofilms Using Materiobiology and Synthetic Biology Approaches

Bacteria form biofilms on material surfaces within hours. Biofilms are often considered problematic substances in the fields such as biomedical devices and the food industry; however, they are beneficial in other fields such as fermentation, water remediation, and civil engineering. Biofilm properties depend on their genome and the extracellular environment, including pH, shear stress, and matrices topography, stiffness, wettability, and charges during biofilm formation. These surface properties have feedback effects on biofilm formation at different stages. Due to emerging technology such as synthetic biology and genome editing, many studies have focused on functionalizing biofilm for specific applications. Nevertheless, few studies combine these two approaches to produce or modify biofilms. This review summarizes up-to-date materials science and synthetic biology approaches to controlling biofilms. The review proposed a potential research direction in the future that can gain better control of bacteria and biofilms.

The Microbial Mechanisms of a Novel Photosensitive Material (Treated Rape Pollen) in Anti-Biofilm Process under Marine Environment

Marine biofouling is a worldwide problem in coastal areas and affects the maritime industry primarily by attachment of fouling organisms to solid immersed surfaces. Biofilm formation by microbes is the main cause of biofouling. Currently, application of antibacterial materials is an important strategy for preventing bacterial colonization and biofilm formation. A natural three-dimensional carbon skeleton material, TRP (treated rape pollen), attracted our attention owing to its visible-light-driven photocatalytic disinfection property. Based on this, we hypothesized that TRP, which is eco-friendly, would show antifouling performance and could be used for marine antifouling. We then assessed its physiochemical characteristics, oxidant potential, and antifouling ability. The results showed that TRP had excellent photosensitivity and oxidant ability, as well as strong anti-bacterial colonization capability under light-driven conditions. Confocal laser scanning microscopy showed that TRP could disperse pre-established biofilms on stainless steel surfaces in natural seawater. The biodiversity and taxonomic composition of biofilms were significantly altered by TRP (p < 0.05). Moreover, metagenomics analysis showed that functional classes involved in the antioxidant system, environmental stress, glucose−lipid metabolism, and membrane-associated functions were changed after TRP exposure. Co-occurrence model analysis further revealed that TRP markedly increased the complexity of the biofilm microbial network under light irradiation. Taken together, these results demonstrate that TRP with light irradiation can inhibit bacterial colonization and prevent initial biofilm formation. Thus, TRP is a potential nature-based green material for marine antifouling.

Customized materials-assisted microorganisms in tumor therapeutics

Microorganisms have been extensively applied as active biotherapeutic agents or drug delivery vehicles for antitumor treatment because of their unparalleled bio-functionalities. Taking advantage of the living attributes of microorganisms, a new avenue has been opened in anticancer research. The integration of customized functional materials with living microorganisms has demonstrated unprecedented potential in solving existing questions and even conferring microorganisms with updated antitumor abilities and has also provided an innovative train of thought for enhancing the efficacy of microorganism-based tumor therapy. In this review, we have summarized the emerging development of customized materials-assisted microorganisms (MAMO) (including bacteria, viruses, fungi, microalgae, as well as their components) in tumor therapeutics with an emphasis on the rational utilization of chosen microorganisms and tailored materials, the ingenious design of biohybrid systems, and the efficacious antitumor mechanisms. The future perspectives and challenges in this field are also discussed.

A light-activated nanotherapeutic with broad-spectrum bacterial recognition to eliminate drug-resistant pathogens

Obstinate infections caused by drug-resistant bacteria severely threaten human health. And the emergence of multidrug-resistant bacteria increases the morbidity and mortality of patients, thus necessitating the development of innovative or alternative therapeutics. Here, a light-activated nanotherapeutic with broad-spectrum bacterial recognition is established as an antibiotic-free therapeutic agent against pathogens. The nanotherapeutic with external phenylboronic acid-based glycopolymers increases the stability and biocompatibility and shows the ability of bacterial recognition. Once irradiated with near-infrared light, this nanotherapeutic with high photothermal conversion efficiency disrupts the cytoplasmic membrane, thus killing bacterial cells. Importantly, it also eliminates the biofilms formed by both drug-resistant Gram-negative bacteria (Pseudomonas aeruginosa) and Gram-positive bacteria (Staphylococcus aureus) effectively. Thus, this antibiotic-free nanotherapeutic with hypotoxicity offers a promising approach to fight increasingly serious antimicrobial resistance.