Antisense vicR-Loaded Dendritic Mesoporous Silica Nanoparticles Regulate the Biofilm Organization and Cariogenicity of Streptococcus mutans

Encapsulation of thyme essential oil in dendritic mesoporous silica nanoparticles: Enhanced antimycotic properties and ROS-mediated inhibition mechanism

Dendritic mesoporous silica nanoparticles (DMSNs) have emerged as promising nanocarriers due to their unique three-dimensional structure and tunable pore characteristics. This study investigates the potential of DMSNs to deliver thyme essential oil (TEO) for enhanced antifungal activity against Fusarium oxysporum (F. oxysporum), a major plant pathogen. DMSNs were successfully synthesized and characterized, followed by the encapsulation of TEO within their porous structure. The resulting TEO@DMSNs composites exhibited significant antifungal activity against F. oxysporum, with inhibition rates reaching 70%, indicating an effective crop protection with a dose-dependent effect. The enhanced antifungal efficacy of TEO@DMSNs compared to free TEO is attributed to the sustained release of TEO and the synergistic effect of the nanocarrier itself. In-depth mechanism investigations revealed that TEO@DMSNs likely disrupted the fungal cell membrane, leading to leakage of cellular contents and ultimately cell death. Moreover, DMSNs and TEO@DMSNs were found to be safe for plant growth, demonstrating their potential as environmentally friendly antifungal agents. This study provides valuable insights into the design and development of advanced nanocarriers for targeted drug delivery and disease management in agriculture.

A Review of Current Developments in Functionalized Mesoporous Silica Nanoparticles: From Synthesis to Biosensing Applications

Functionalized mesoporous silica nanoparticles (MSNs) have been widely investigated in the fields of nanotechnology and material science, owing to their high surface area, diverse structure, controllable cavity, high biocompatibility, and ease of surface modification. In the past few years, great efforts have been devoted to preparing functionalized MSNs for biosensing applications with satisfactory performance. The functional structure and composition in the synthesis of MSNs play important roles in high biosensing performance. With the development of material science, diverse functional units have been rationally incorporated into mesoporous structures, which endow MSNs with design flexibility and multifunctionality. Here, an overview of the recent developments of MSNs as nanocarriers is provided, including the methodologies for the preparation of MSNs and the nanostructures and physicochemical properties of MSNs, as well as the latest trends of MSNs and their use in biosensing. Finally, the prospects and challenges of MSNs are presented.

Temporin-Derived Peptides Disrupt the Exopolysaccharide Matrix of Streptococcus mutans to Prevent Related Dental Caries

Dental caries, the most prevalent oral infectious disease, is closely associated with Streptococcus mutans. This study investigates the antimicrobial properties of the temporin-GHb peptide and its derivatives (GHbR, GHbK, and GHb3K) against S. mutans. These peptides exhibited potent anti-S. mutans activity through a membrane-disruptive mechanism, confirmed by flow cytometry and fluorescence staining assays while showing lower bactericidal effects on beneficial probiotic bacteria. Additionally, they inhibited the biofilm matrix formation by disrupting extracellular polysaccharide (EPS) synthesis, as demonstrated by zymography, qRT-PCR, and sucrose metabolism experiments. In a rat model of S. mutans-induced dental caries, treatment with these peptides significantly reduced the incidence of dental lesions. H&E staining analysis of rat oral tissues confirmed the biosafety of GHb and GHb3K. These findings suggest that temporin-derived peptides effectively target EPS, inhibiting biofilm formation and virulence, offering a promising strategy for preventing dental caries and promoting oral health. The findings suggest potential applications for peptide-based interventions to mitigate biofilm-related issues across various fields, including agriculture, food processing, and healthcare.

Targeting bacterial biofilm-related genes with nanoparticle-based strategies

Persistent infection caused by biofilm is an urgent in medicine that should be tackled by new alternative strategies. Low efficiency of classical treatments and antibiotic resistance are the main concerns of the persistent infection due to biofilm formation which increases the risk of morbidity and mortality. The gene expression patterns in biofilm cells differed from those in planktonic cells. One of the promising approaches against biofilms is nanoparticle (NP)-based therapy in which NPs with multiple mechanisms hinder the resistance of bacterial cells in planktonic or biofilm forms. For instance, NPs such as silver (Ag), zinc oxide (ZnO), titanium dioxide (TiO2), copper oxide (Cu), and iron oxide (Fe3O4) through the different strategies interfere with gene expression of bacteria associated with biofilm. The NPs can penetrate into the biofilm structure and affect the expression of efflux pump, quorum-sensing, and adhesion-related genes, which lead to inhibit the biofilm formation or development. Therefore, understanding and targeting of the genes and molecular basis of bacterial biofilm by NPs point to therapeutic targets that make possible control of biofilm infections. In parallel, the possible impact of NPs on the environment and their cytotoxicity should be avoided through controlled exposure and safety assessments. This study focuses on the biofilm-related genes that are potential targets for the inhibition of bacterial biofilms with highly effective NPs, especially metal or metal oxide NPs.

Biocompatible formulation of a hydrophobic antimicrobial peptide L30 through nanotechnology principles and its potential role in mouse pneumonia model infected with Staphylococcus aureus

Hydrophobic antimicrobial peptide L30, a potential antibiotic candidate, has poor water solubility and hemolytic activity. Herein, a biocompatible nano-formulation composed of liposomes and dendritic mesoporous silica encapsulation (LDMSNs@L30) was constructed for L30 to solve the limits for its clinical development. The characterization, antimicrobial activity and therapeutic effect of LDMSNs@L30 on Staphylococcus aureus 9 (cfr+) infected mice models were investigated. LDMSNs@L30 displayed a smooth, spherical, and monodisperse nanoparticle with a hydrodynamic diameter of 177.40 nm, an encapsulation rate of 56.13%, a loading efficiency of 32.26%, a release rate of 66.5%, and effective slow-release of L30. Compared with free L30, the formulation could significantly increase the solubility of L30 in PBS with the maximum concentration from 8 μg/mL to 2.25 mg/mL and decrease the hemolytic activity of hydrophobic peptide L30 with the HC5 from 65.36 μg/mL to more than 500 μg/mL. The nano delivery system LDMSNs@L30 also exhibited higher therapeutic effects on mice models infected with S. aureus 9 (cfr+) than those of free L30 after 7 days of treatment by reducing the lung inflammation and the inflammatory cytokines levels in plasma, showing better health score and pulmonary pathological improvement. Our research suggests that nano-formulation can be expected to be a promising strategy for peptide drugs in therapeutic applications.

Pudilan Keyanning mouthwash inhibits dextran-dependent aggregation and biofilm organization of Streptococcus mutans

AIMS

This research aimed to investigate the inhibitory effects of Pudilan mouthwash (PDL) on Streptococcus mutans (S. mutans) biofilms and identify its chemical components.

METHODS AND RESULTS

The impacts of 100% concentrated PDL on S. mutans biofilm were detected by colony-forming unit (CFU) assays, crystal violet staining, confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), and quantitative real-time PCR (qRT‒PCR). The biocompatibility with human gingival fibroblasts (HGFs) was evaluated by Cell-Counting-Kit-8 (CCK-8) assay. And chemical components were identified by UPLC-HRMS. PBS and 0.12% chlorhexidine were used as negative and positive controls, respectively. Results indicate early 8-h S. mutans biofilms are sensitive to PDL. Additionally, it leads to a decrease in bacterial activities and dextran-dependent aggregation in 24-h S. mutans biofilms. PDL significantly downregulates the gene expression of gtfB/C/D and smc. And 114 components are identified.

CONCLUSIONS

PDL has an inhibitory effect on S. mutans and favorable biocompatibility. It has potential to be exploited as a novel anti-biofilm agent.

Antimicrobial peptide temporin derivatives inhibit biofilm formation and virulence factor expression of Streptococcus mutans

Introduction

Temporin-GHa obtained from the frog Hylarana guentheri showed bactericidal efficacy against Streptococcus mutans. To enhance its antibacterial activity, the derived peptides GHaR and GHa11R were designed, and their antibacterial performance, antibiofilm efficacy and potential in the inhibition of dental caries were evaluated.

Methods

Bacterial survival assay, fluorescent staining assay and transmission electron microscopy observation were applied to explore how the peptides inhibited and killed S. mutans. The antibiofilm efficacy was assayed by examining exopolysaccharide (EPS) and lactic acid production, bacterial adhesion and cell surface hydrophobicity. The gene expression level of virulence factors of S. mutans was detected by qRT-PCR. Finally, the impact of the peptides on the caries induced ability of S. mutans was measured using a rat caries model.

Results

It has been shown that the peptides inhibited biofilm rapid accumulation by weakening the initial adhesion of S. mutans and reducing the production of EPS. Meanwhile, they also decreased bacterial acidogenicity and aciduricity, and ultimately prevented caries development in vivo.

Conclusion

GHaR and GHa11R might be promising candidates for controlling S. mutans infections.

A Chinese herb preparation, honokiol, inhibits Streptococcus mutans biofilm formation

OBJECTIVE

This study aimed to investigate the antibiofilm and anticariogenic effects of honokiol, a traditional Chinese medicine, on the cariogenic bacterium Streptococcus mutans (S. mutans).

DESIGN

The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of honokiol on S. mutans UA159 were measured. Then, S. mutans were treated with honokiol at concentrations of 1/2 MIC and 1/4 MIC. Extracellular polysaccharide (EPS) synthesis was assessed with confocal laser scanning microscopy (CLSM) and the anthrone-sulfuric method. Crystal violet staining and scanning electron microscopy (SEM) were used to demonstrate the characteristics and morphology of S. mutans biofilms. Colony-forming unit (CFU) assay was performed to observe the antibacterial effect of honokiol. Lactic acid production of 24-h biofilms was measured by the lactic acid assay. The expression level of caries-related genes (gtfB/C/D, comD/E and ldh) was identified by quantitative real-time PCR (qRTPCR) to explore the relevant mechanism. And the cytotoxic effect on human gingival fibroblasts (HGFs) was evaluated by the Cell Counting Kit-8 (CCK-8) assay.

RESULTS

The MIC and MBC of honokiol on S. mutans were 30 μg/mL and 60 μg/mL, respectively. Honokiol inhibited biofilm formation, EPS synthesis and lactic acid production. It also decreased the expression of glucosyltransferases (Gtfs) and quorum sensing (QS) system encoding genes. Moreover, honokiol showed favorable biocompatibility with HGFs.

CONCLUSIONS

Honokiol has an inhibitory effect on S. mutans and favorable biocompatibility, with application potential as a novel anticaries agent.

Delivery of Therapeutic Biopolymers Employing Silica-Based Nanosystems

The use of nanoparticles is crucial for the development of a new generation of nanodevices for clinical applications. Silica-based nanoparticles can be tailored with a wide range of functional biopolymers with unique physicochemical properties thus providing several advantages: (1) limitation of interparticle interaction, (2) preservation of cargo and particle integrity, (3) reduction of immune response, (4) additional therapeutic effects and (5) cell targeting. Therefore, the engineering of advanced functional coatings is of utmost importance to enhance the biocompatibility of existing biomaterials. Herein we will focus on the most recent advances reported on the delivery and therapeutic use of silica-based nanoparticles containing biopolymers (proteins, nucleotides, and polysaccharides) with proven biological effects.

A macrophage membrane-coated mesoporous silica nanoplatform inhibiting adenosine A2AR via in situ oxygen supply for immunotherapy

Immunotherapy has achieved remarkable research outcomes and shows the potential to cure cancer. However, its therapeutic response is limited in terms of the immunosuppressive tumor microenvironment induced by hypoxia, in which the adenosinergic A2A receptor (A2AR) pathway is mainly participated. Here, we developed a novel core/shell structured nanoplatform composed of macrophage membrane-coated mesoporous silica nanoparticles which loaded catalase, doxorubicin (Dox), and resiquimod (R848), to promote the efficacy of immunotherapy. The nanoplatform is able to actively target the tumor site via ligand binding, and the A2AR of T regulatory (Treg) cells can further be blocked due to in situ oxygen production by hydrogen peroxide catalysis. Meanwhile, Dox and R848 released from the nanoplatform can induce immunogenic cell death and enhance the activation of dendritic cells (DCs), respectively. Thus, the improved microenvironment by A2AR blockade and the stimulation of the DCs to enhance the CD8⁺ T cells mediated immune response were achieved. Consequently, the expression of Treg cells decreased to 9.79% in tumor tissue and the inhibition rate of tumor growth reached 73.58%. Therefore, this nanoplatform provides a potential strategy for clinical application in cancer immunotherapy.