Synthesis and evaluation of the antibacterial effect of silica-coated modified magnetic poly-(amidoamine) G5 nanoparticles on E. coli and S. aureus

Adaptive Responses of a Peroxidase-like Polyoxometalate-Based Tri-Assembly to Bacterial Microenvironment (BME) Significantly Improved the Anti-Bacterial Effects

The present study presents the tertiary assembly of a POM, peptide, and biogenic amine, which is a concept to construct new hybrid bio-inorganic materials for antibacterial applications and will help to promote the development of antivirus agents in the future. To achieve this, a Eu-containing polyoxometalate (EuW₁₀) was first co-assembled with a biogenic amine of spermine (Spm), which improved both the luminescence and antibacterial effect of EuW₁₀. Further introduction of a basic peptide from HPV E6, GL-22, induced more extensive enhancements, both of them being attributed to the cooperation and synergistic effects between the constituents, particularly the adaptive responses of assembly to the bacterial microenvironment (BME). Further intrinsic mechanism investigations revealed in detail that the encapsulation of EuW₁₀ in Spm and further GL-22 enhanced the uptake abilities of EuW₁₀ in bacteria, which further improved the ROS generation in BME via the abundant H₂O₂ involved there and significantly promoted the antibacterial effects.

Silver-dendrimer nanocomposite as emerging therapeutics in anti-bacteria and beyond

To develop next-generation nanomedicine, theranostic nanotherapeutic strategies are increasingly being emphasized. In recent years, it is observed that the effective lifetime of anti-bacterial and anti-cancer agent is diminishing, which undermines the economic incentives necessary for clinical development and therapeutic applications. Thus, novel formulations ought to not only kill drug resistant strains and cancerous cells but also inhibit their formation. Recently, metallic nanoparticles [for example- silver (Ag) nanoparticles] have been widely investigated for their biomedical applications. The so-called applications necessitate the inclusion of these nanoparticles inside polymeric matrices (for example- dendrimer) leading to chemical functionalization of the metallic nanoparticles. Silver and silver nanoparticles' antibacterial activity has already been well established over years. Dendrimers due to their homogeneous highly branched structure and uniform composition are perfectly suitable for the inclusion of silver nanoparticles [Ag NPs]. Recently, the increasing trend in the development of Ag-dendrimer nanocomposites is attributed to the excellent antibacterial activity of Ag as well as dendrimer's unique properties like variable functional terminal ends and potential antibacterial effect necessarily. This review provides an informative overview regarding the numerous aspects of bactericidal and other biomedical applications of Ag-dendrimer nanocomposites, particularly emphasizing analysis of existing research and prospective worth to the pharmaceutical sector in future.

Biological Applications of Silica-Based Nanoparticles

Silica nanoparticles have been widely explored in biomedical applications, mainly related to drug delivery and cancer treatment. These nanoparticles have excellent properties, high biocompatibility, chemical and thermal stability, and ease of functionalization. Moreover, silica is used to coat magnetic nanoparticles protecting against acid leaching and aggregation as well as increasing cytocompatibility. This review reports the recent advances of silica-based magnetic nanoparticles focusing on drug delivery, drug target systems, and their use in magnetohyperthermia and magnetic resonance imaging. Notwithstanding, the application in other biomedical fields is also reported and discussed. Finally, this work provides an overview of the challenges and perspectives related to the use of silica-based magnetic nanoparticles in the biomedical field.

Antibacterial effect of TiO2 modified with poly-amidoamine dendrimer - G3 on S. aureus and E. coli in aqueous solutions

This study investigated bacterial removal using TiO₂ nanoparticles (NPs) modified with poly-amidoamine dendrimer macromolecule (PAMAM, G3). The PAMAM G3/TiO₂ (nanohybrid) was used to specify antibacterial properties via broth microdilution (MBC-Minimum Bactericidal Concentration and MIC-Minimum Inhibitory Concentration-determination), paper disc diffusion, and surface plate count methods. The nanohybrid was characterized via the different techniques. The effects of different factors including initial bacteria count, run time, solution pH, and the nanohybrid concentration were studied. The nanohybrid cytotoxicity was studied on AGS and MKN45 cells line by MTT assay. It was revealed that the nanohybrid was effective in intercepting both bacterial strains growth. The MIC value for S. aureus and E. coli were determined to be 4 and 2 μg/mL, respectively. The MBC value for both strains were calculated to be 32 μg/mL. The results showed removal efficiency of 100% for S. aureus and E. coli bacteria in optimum situation. The decrease in cell viability in the dosage of 32 μg/mL after 72 h treatment for AGS and MKN45 cells line were shown to be 6.2 and 4.6%, respectively. The nanohybrid was able to decrease the S. aureus and E. coli count in solution, which meets the drinking water criterions aligned with WHO guidelines.

Preparation and evaluation of polyphenol derivatives as potent antifouling agents: addition of a side chain affects the biological activity of polyphenols

In this study, eight polyphenol derivatives were prepared to serve as green antifoulants. Polyphenol derivatives, which can hinder the growth of bacteria and algae and decrease the adhesion of some marine organisms, showed good AF activity; in particular, the activities of these derivatives were much higher than those of the corresponding polyphenols. The antibacterial rates of the products (20 μg ml^-1) exceeded 88%. Moreover, the anti-algal rates of compounds a3, b1, b2, b3 and b4 (15 μg ml^-1) were over 57% at 240 h, but these compounds showed low toxicity, and the 120 h EC₅₀ values were > 6.60 μg ml^-1. In addition, there were fewer marine microorganisms on the test panel than on the control. The above results show that some polyphenol derivatives possess relatively high antibacterial, anti-algal, and AF activity; more notably, the addition of chlorine atoms and amide groups can further increase the activity of these derivatives.

Poly (amidoamine) generation 6 functionalized Fe3O4@SiO2/GPTMS core-shell magnetic NPs as a new adsorbent for Arsenite adsorption: kinetic, isotherm and thermodynamic studies

In this survey a new route has been developed the preparation of poly (amidoamine) generation 6 (PAMAM-G6) dendrimer functionalized Fe3O4/SiO2 nanoparticle and was used for arsenite (As (III)) adsorption. SiO2 was first grafted onto the surface of Fe3O4 to formation a core-shell structure. Then the introduction of epoxy rings were done by hydrolysis of methylsilane groups of 3-Glycidoxypropyltrimethoxysilane (GPTMS) on OH groups of SiO2 and afterwards, PAMAM-G6 reacted with epoxy rings of GPTMS to obtain a multiamino magnetic adsorbent. The as-prepared nanocomposite was characterized by TEM, Zeta potential, FESEM, VSM, FTIR, Raman and XPS techniques. The effects of reaction time from 5 to 50 min, initial As (III) concentration in the range of 1-10 mgL-1, initial adsorbent concentration in the range of 10-50 mgL-1 and initial pH in the range 3-8 were studied. The resulting of kinetic and isotherm models displays high adsorption affinity (233 mg/g) for As (III) and the adsorbent can reach the adsorbent can reach the adsorption equilibrium at a neutral pH (7). The As (III) loaded nanocomposite could be separated readily from aqueous solution by magnetic and regenerated simply via NaOH. The study of the adsorption procedure showed that the pseudo-second order kinetics and Langmuir isotherm well-fitted with the experimental data of As (III) adsorption onto nanocomposite.