Antimicrobial efficacy of green synthesized drug blended silver nanoparticles against dental caries and periodontal disease causing microorganisms

Nanoparticles in Periodontitis Therapy: A Review of the Current Situation

Periodontitis is a disease of inflammation that affects the tissues supporting the periodontium. It is triggered by an immunological reaction of the gums to plaque, which leads to the destruction of periodontal attachment structures. Periodontitis is one of the most commonly recognized dental disorders in the world and a major factor in the loss of adult teeth. Scaling and root planing remain crucial for managing patients with persistent periodontitis. Nevertheless, exclusive reliance on mechanical interventions like periodontal surgery, extractions, and root planning is insufficient to halt the progression of periodontitis. In response to the problem of bacterial resistance, some researchers are committed to finding alternative therapies to antibiotics. In addition, some scholars focus on finding new materials to provide a powerful microenvironment for periodontal tissue regeneration and promote osteogenic repair. Nanoparticles possess distinct therapeutic qualities, including exceptional antibacterial, anti-inflammatory, and antioxidant properties, immunomodulatory capacities, and the promotion of bone regeneration ability, which made them can be used for the treatment of periodontitis. However, there are many problems that limit the clinical translation of nanoparticles, such as toxic accumulation in cells, poor correlation between in vitro and in vivo, and poor animal-to-human transmissibility. In this paper, we review the present researches on nanoparticles in periodontitis treatment from the perspective of three main categories: inorganic nanoparticles, organic nanoparticles, and nanocomposites (including nanofibers, hydrogels, and membranes). The aim of this review is to provide a comprehensive and recent update on nanoparticles-based therapies for periodontitis. The conclusion section summarizes the opportunities and challenges in the design and clinical translation of nanoparticles for the treatment of periodontitis.

Effectiveness of nanosilver fluoride and silver diamine fluoride in arresting early childhood caries: a randomized controlled clinical trial

BACKGROUND

One of the most prevalent health problems affecting children worldwide is untreated caries in primary teeth. Agents to arrest caries are used to manage untreated decay in children in disadvantaged communities. Nano Silver Fluoride (NSF) overcomes the staining problems of Silver Diamine Fluoride (SDF). This study compared the clinical cariostatic effect of NSF to 38% SDF for arresting caries lesions.

METHODS

The study included 360 children younger than 4 years, with at least one active lesion, ICDAS score ≥ 3, recruited from nurseries in a rural area in Alexandria, Egypt, in 2022. They were randomly assigned to receive a single application of NSF at baseline, or two applications of SDF at baseline and after 6 months. The arrest of active carious lesions was assessed after 6 and 12 months using ICDAS criteria, and parents' satisfaction with child appearance was also assessed. Chi-Square test was used to compare the groups and multi-level multiple logistic regression was used to assess the effect of the intervention on caries arrest at lesion level and binary logistic regression was used to assess the effect at patient level.

RESULTS

1853 active lesions were included in children whose mean (SD) age was 42.3 (8.2) months. The arrest rate was significantly higher in the NSF than the SDF group at lesion level (78.4% and 65.0% at 6 months and 71.3% and 56.3% at 12 months, p < 0.001). In regression analysis, NSF had significantly higher odds of caries arrest than SDF at lesion level (at 6 months, AOR = 2.57, 95% CI: 1.55, 4.26 and at 12 month, AOR = 3.27, 95% CI: 1.89, 5.67). Parents of children receiving NSF had significantly greater satisfaction with their children's dental appearance than those receiving SDF: (97.2% and 76.1%, respectively, p < 0.001).

CONCLUSION

NSF demonstrated greater effectiveness in arresting caries in preschool children without inducing black staining of teeth and with greater parental satisfaction than SDF. NSF can be an alternative to SDF in arresting caries especially in underprivileged communities.

TRIAL REGISTRATION

The trial was registered in the clinicaltrials.gov registry (#NCT05255913)-16/02/2022.

Bio-inspired synthesis of silver nanoparticles usingSalsola imbricataand its application as antibacterial additive in glass ionomer cement

Nanotechnology has gained immense popularity and observed rapid development due to the remarkable physio-chemical properties of nanoparticles (NPs) and related nanomaterials. The green production of NPs has many benefits over traditional techniques because the current procedures are expensive, time-consuming, and involve harmful substances that limit their applicability. This study aimed to use a novel green source, theSalsola imbricata(SI) plant, which is commonly found in Central Asia and known for its medicinal properties as a reducing and stabilizing agent for the synthesis of AgNPs. The current study also utilized efficient statistical design, the Plackett-Burman Design (PBD) of Experiment method to synthesize the NPs. The characterization of NPs was carried out using UV-Vis spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy (SEM). The PBD results showed that only two out of four factorsi.e.AgNO3concentration and incubation time, were significant for the synthesis of SI-AgNPs. While remaining factors, incubation temperature and plant extract: AgNO3ratio were non-significant. The SEM analysis result showed that SI-AgNPs had a size of 20-50 nm. The SI-AgNPs demonstrated strong antibacterial activity against oral pathogens such asS. mutans and Lactobacillus acidophilus, with the highest efficacy observed at a concentration of 2 mg ml-1. The addition of SI-AgNPs in glass ionomer cement significantly increased the antibacterial activity of GIC againstS. mutans. Based on the results of the current study, the plant based AgNPs can be further evaluated in detail as alternate antimicrobial agent either alone or in combination with other antimicrobial agents for different dental applications.

Green Synthesis of Ganoderma Lucidum-Mediated Silver Nanoparticles and its Microbial Activity against Oral Pathogenic Microbes: An In Vitro Study

Nanotechnology is developing into a fast-expanding discipline with applications in science and technology, and nanostructures are a crucial research tool in many fields. Due to their remarkable electrical, optical, magnetic, catalytic, and pharmacological capabilities, metal and metal oxide nanoparticles (NPs) have drawn study interest. Natural elements (plants, microorganisms, fungi, etc.) are utilized in a chemical-free, environmentally benign way to synthesize metals and metal oxides. The optical, electrical, and antimicrobial qualities of silver nanoparticle (AgNP) make them a popular choice. More than 200 active ingredients, including water-soluble, organic-soluble, and volatile chemicals, are found in Ganoderma. The main components are polysaccharides, adenosine, and terpenoids, each of which has exceptional therapeutic properties. This article explains the synthesis of Ag NPs by Ganoderma lucidum and tests the antibacterial effectiveness for use in biological applications.

Evaluation of the antifungal effect of plant extracts on oral Candidaspp. - a critical methodological analysis of the last decade

INTRODUCTION

In 2022, the World Health Organization published a report encouraging researchers to focus on Candida spp. to strengthen the global response to fungal oral infections and antifungal resistance. In the context of innovative research, it seems pertinent to investigate the antifungal potential of natural extracts of plants and the methodology involved in the recent reports. The aim of this systematic review is to identify the current state of in vitro research on the evaluation of the ability of plant extracts to inhibit Candida spp.

MATERIAL AND METHODS

A bibliographic search has been developed to on a 10-year period to identify which plant extracts have an antifungal effect on the Candida spp. found in the oral cavity.

RESULTS

A total of 20 papers were reviewed and fulfilled all the selection criteria and were included in the full data analysis.

DISCUSSION

Plants have been tested in a wide range of states - whole extracts, extraction of particular components such as flavonoids or polyphenols, or even using the plant to synthesize nanoparticles. Of forty-five plants tested, five of them did not show any effect against Candida spp., which weren't part of the same family. There is a wide range of plant that exhibit antifungal proprieties.

CONCLUSION

Many plants have been tested in a wide range of states - whole extracts, extraction of components such as flavonoids or polyphenols, or even using the plant to synthetize nanoparticles. The combination of plants, the addition of plants to a traditional antifungal and the interference with adhesion provided by some plants seem to be promising strategies. Nonetheless, on contrary to drugs, there is a critical lack of standardization on methodologies and protocols, which makes it difficult to compare data and, consequently, to conclude, beyond doubts, about the most promising plants to fight Candida spp. oral infections.

Silver nanoparticles biogenically synthesised using Maclurodendron porteri extract and their bioactivities

Silver nanoparticle is widely used in various field including medical, cosmetic, food and industrial purposes due to their unique properties in electrical conductivity, thermal, and biological activities. In the medical field, silver nanoparticles (AgNPs) have been reported to have strong antimicrobial and cytotoxic activities. This study aimed to synthesize and characterize silver nanoparticles (AgNPs) using Maclurodendron porteri (MP) extract and to evaluate the antimicrobial and cytotoxic activities of the synthesised MP-AgNPs. Green method of Ultrasound Assisted Extraction (UAE) was used to extract the leaves of M. porter. Liquid Chromatography -Mass Spectrometry/Quadrupole time-of-flight (LC-MS/QTOF) was used to identify the compounds in the leaf extract of M. porteri. Characterisation of the synthesised nanoparticles involved ultraviolet-visible (UV-Vis), Fourier Transform Infrared (FTIR), scanning electromagnetic microscopy (SEM), Zeta potential Analyzer and Particle Size Analyzer. The cytotoxic assay was conducted on MCF-7 and Caco-2 cell lines by MTT assay. Antimicrobial activity was tested on Gram-negative and Gram-positive bacteria using the disc diffusion method. Based on LC-MS/QTOF analysis, 430 compounds were found. The identified major compounds consist of amino acids, polyphenols, steroids, terpenoids and heterocyclic compounds which possibly act as reducing agents. 1 mM, 5 mM and 10 mM of silver nitrate solution were mixed with the leaf extract to form silver nanoparticles. 1.2 mg/ml of MP-AgNPs were found to have antibacterial activity against B. subtilis, S. aureus, E. coli, and P. aeruginosa with inhibitory zones of 8.0 ± 0.36 mm, 8.5 ± 0.45 mm, 7.5 ± 0.36 mm, and 9.0 ± 0.40 mm respectively. MP-AgNPs showed no cytotoxic activity against Caco-2 and MCF-7 cells. In conclusion, the presence of major amine compounds such as 10,11-dihydro-10,11-dihydroxyprotriptyline and harderoporphyrin in the extract facilitated the synthesis of AgNPs and the nanoparticle showed weak bioactivities in the assay conducted.

Spotlight on therapeutic efficiency of green synthesis metals and their oxide nanoparticles in periodontitis

Periodontitis, one of the most prevalent dental diseases, causes the loss of bone and gum tissue that hold teeth in place. Several bacteria, commonly present in clinically healthy oral cavities, may induce and perpetuate periodontitis when their concentration rises in the gingival sulcus. Antibacterial effect against various Gram-negative and Gram-positive bacteria, including pathogenic and drug-resistant ones, has been shown for several distinct transient metal and metal oxide NPs. Therefore, NPs may be used in biomedicine to treat periodontal problems and in nanotechnology to inhibit the development of microorganisms. Instead of using harmful chemicals or energy-intensive machinery, biosynthesis of metal and metal oxide nanoparticles (NPs) has been suggested. To produce metal and metal oxide NPs, the ideal technique is "Green" synthesis because of its low toxicity and safety for human health and the environment. Gold NPs (AuNPs) appear to be less toxic to mammalian cells than other nanometals because their antibacterial activity is not dependent on reactive oxygen species (ROS). AgNPs also possess chemical stability, catalytic activity, and superior electrical and thermal conductivity, to name a few of their other advantageous characteristics. It was observed that zinc oxide (ZnO) NPs and copper (Cu) NPs exhibited discernible inhibitory effects against gram-positive and gram-negative bacterial strains, respectively. ZnO NPs demonstrated bactericidal activity against the microorganisms responsible for periodontitis. Medications containing magnetic NPs are highly effective against multidrug-resistant bacterial and fungal infections. The titanium dioxide (TiO2) NPs are implicated in elevating salivary peroxidase activity in individuals diagnosed with chronic periodontitis. Furthermore, specific metallic NPs have the potential to enhance the antimicrobial efficacy of periodontitis treatments when combined. Therefore, these NPs, as well as their oxide NPs, are only some of the metals and metal oxides that have been synthesized in environmentally friendly ways and shown to have therapeutic benefits against periodontitis.

Ebselen Optimized the Therapeutic Effects of Silver Nanoparticles for Periodontal Treatment

Objective

Silver nanoparticles (AgNPs) possess excellent antibacterial effects on periodontal pathogens, but their clinical application is limited mainly due to their cytotoxicity through inducing oxidative stress in human cells. Ebselen disrupts the reactive oxygen species (ROS) scavenging in bacteria and relieves oxidative stress in mammalian cells. This study aimed to assess the antibacterial and anti-inflammatory effects of AgNPs and ebselen as well as the protective effect of ebselen, to further provide the theoretical basis for their future application in periodontal treatment.

Methods

The antibacterial and anti-biofilm effects of the synthesized AgNPs combined with ebselen were assessed on Porphyromonas gingivalis (P. gingivalis), Streptococcus gordonii (S. gordonii), and Fusobacterium nucleatum (F. nucleatum) in planktonic condition and as biofilms. In addition, the intracellular bactericidal efficiency of AgNPs and ebselen was evaluated in P. gingivalis-infected human gingival fibroblasts (HGFs). The cytotoxicity, intracellular ROS levels, and potential antioxidative enzymes were detected in HGFs treated with AgNPs and ebselen. Further, the anti-inflammatory effects were evaluated by in vitro and in vivo experiments.

Results

The combination of AgNPs and ebselen showed excellent antibacterial effects against planktonic P. gingivalis and F. nucleatum and synergistic antibiofilm effects on all mono- and multi-species biofilms. In addition, ebselen significantly enhanced the intracellular bactericidal efficiency of AgNPs. Furthermore, ebselen combined with up to 20 μg/mL AgNPs showed no obvious cytotoxicity to HGFs. Evidently, ebselen alleviated the AgNPs-induced ROS by increasing the levels of glutathione and superoxide dismutase 2. Moreover, AgNPs and ebselen together declined the release of P. gingivalis-stimulated inflammatory cytokines both in vitro and in vivo, and reduced alveolar bone resorption effectively.

Conclusion

AgNPs combined with ebselen would be an effective adjuvant for periodontal treatment owing to their synergistic antibacterial and anti-inflammatory effects.

Supra and subgingival application of antiseptics or antibiotics during periodontal therapy

Periodontal diseases (gingivitis and periodontitis) are characterized by inflammatory processes which arise as a result of disruption of the balance in the oral ecosystem. According to the current S3 level clinical practice guidelines, therapy of patients with periodontitis involves a stepwise approach that includes the control of the patient's risk factors and the debridement of supra and subgingival biofilm. This debridement can be performed with or without the use of some adjuvant therapies, including physical or chemical agents, host modulating agents, subgingivally locally delivered antimicrobials, or systemic antimicrobials. Therefore, the main aim of this article is to review in a narrative manner the existing literature regarding the adjuvant application of local agents, either subgingivally delivered antibiotics and antiseptics or supragingivally applied rinses and dentifrices, during the different steps in periodontal therapy performed in Europe.

Padina boergesenii-Mediated Copper Oxide Nanoparticles Synthesis, with Their Antibacterial and Anticancer Potential

The utilization of nanoparticles derived from algae has generated increasing attention owing to their environmentally sustainable characteristics and their capacity to interact harmoniously with biologically active metabolites. The present study utilized P. boergesenii for the purpose of synthesizing copper oxide nanoparticles (CuONPs), which were subsequently subjected to in vitro assessment against various bacterial pathogens and cancer cells A375. The biosynthesized CuONPs were subjected to various analytical techniques including FTIR, XRD, HRSEM, TEM, and Zeta sizer analyses in order to characterize their stability and assess their size distribution. The utilization of Fourier Transform Infrared (FTIR) analysis has provided confirmation that the algal metabolites serve to stabilize the CuONPs and function as capping agents. The X-ray diffraction (XRD) analysis revealed a distinct peak associated with the (103) plane, characterized by its sharpness and high intensity, indicating its crystalline properties. The size of the CuONPs in the tetragonal crystalline structure was measured to be 76 nm, and they exhibited a negative zeta potential. The biological assay demonstrated that the CuONPs exhibited significant antibacterial activity when tested against both Bacillus subtilis and Escherichia coli. The cytotoxic effects of CuONPs and cisplatin, when tested at a concentration of 100 µg/mL on the A375 malignant melanoma cell line, were approximately 70% and 95%, respectively. The CuONPs that were synthesized demonstrated significant potential in terms of their antibacterial properties and their ability to inhibit the growth of malignant melanoma cells.

Bioactive Glass Modified with Zirconium Incorporation for Dental Implant Applications: Fabrication, Structural, Electrical, and Biological Analysis

Implantology is crucial for restoring aesthetics and masticatory function in oral rehabilitation. Despite its advantages, certain issues, such as bacterial infection, may still arise that hinder osseointegration and result in implant rejection. This work aims to address these challenges by developing a biomaterial for dental implant coating based on 45S5 Bioglass^® modified by zirconium insertion. The structural characterization of the glasses, by XRD, showed that the introduction of zirconium in the Bioglass network at a concentration higher than 2 mol% promotes phase separation, with crystal phase formation. Impedance spectroscopy was used, in the frequency range of 10²-10⁶ Hz and the temperature range of 200-400 K, to investigate the electrical properties of these Bioglasses, due to their ability to store electrical charges and therefore enhance the osseointegration capacity. The electrical study showed that the presence of crystal phases, in the glass ceramic with 8 mol% of zirconium, led to a significant increase in conductivity. In terms of biological properties, the Bioglasses exhibited an antibacterial effect against Gram-positive and Gram-negative bacteria and did not show cytotoxicity for the Saos-2 cell line at extract concentrations up to 25 mg/mL. Furthermore, the results of the bioactivity test revealed that within 24 h, a CaP-rich layer began to form on the surface of all the samples. According to our results, the incorporation of 2 mol% of ZrO₂ into the Bioglass significantly improves its potential as a coating material for dental implants, enhancing both its antibacterial and osteointegration properties.

Updates on Biogenic Metallic and Metal Oxide Nanoparticles: Therapy, Drug Delivery and Cytotoxicity

The ambition to combat the issues affecting the environment and human health triggers the development of biosynthesis that incorporates the production of natural compounds by living organisms via eco-friendly nano assembly. Biosynthesized nanoparticles (NPs) have various pharmaceutical applications, such as tumoricidal, anti-inflammatory, antimicrobials, antiviral, etc. When combined, bio-nanotechnology and drug delivery give rise to the development of various pharmaceutics with site-specific biomedical applications. In this review, we have attempted to summarize in brief the types of renewable biological systems used for the biosynthesis of metallic and metal oxide NPs and the vital contribution of biogenic NPs as pharmaceutics and drug carriers simultaneously. The biosystem used for nano assembly further affects the morphology, size, shape, and structure of the produced nanomaterial. The toxicity of the biogenic NPs, because of their pharmacokinetic behavior in vitro and in vivo, is also discussed, together with some recent achievements towards enhanced biocompatibility, bioavailability, and reduced side effects. Because of the large biodiversity, the potential biomedical application of metal NPs produced via natural extracts in biogenic nanomedicine is yet to be explored.

Green synthesis of silver nanoparticles mediated Diospyros kaki L. (Persimmon): determination of chemical composition and evaluation of their antimicrobials and anticancer activities

The eco-friendly synthesis of metallic nanoparticles (MNPs) using biological materials is an encouraging and innovativeness approach to nanotechnology. Among other synthesizing methods, biological methods are chosen because of their high efficiency and purity in many aspects. In this work, using the aqueous extract obtained from the green leaves of the D. kaki L. (DK); silver nanoparticles were synthesized in a short time and simply with an eco-friendly approach. The properties of the synthesized silver nanoparticles (AgNPs) were characterized using various techniques and measurements. In the characterization data of AgNPs, Maximum absorbance at 453.34 nm wavelengths, the average size distribution of 27.12 nm, the surface charge of -22.4 mV, and spherical appearance were observed. LC-ESI-MS/MS analysis was used to assess the compound composition of D. kaki leaf extract. The chemical profiling of the crude extract of D. kaki leaves revealed the presence of a variety of phytochemicals, predominantly phenolics, resulting in the identification of five major high-feature compounds: two major phenolic acids (Chlorogenic acid and Cynarin), and tree flavonol glucosides (hyperoside, quercetin-3-glucoside, and quercetin-3- D-xyloside). The components with the highest concentrations were cynarin, chlorogenic acid, quercetin-3- D-xyloside, hyperoside, and quercetin-3-glucoside, respectively. Antimicrobial results were determined by a MIC assay. The biosynthesized AgNPs exhibited strong antibacterial activity against the human and food pathogen Gram (+ and -) bacteria and good antifungal activity against pathogenic yeast. It was determined that 0.03-0.050 μg/mL concentrations ranges of DK-AgNPs were growth suppressive concentrations on all pathogen microorganisms. The MTT technique was used to study the cytotoxic effects of produced AgNPs on cancer cell lines (Glioblastoma (U118), Human Colorectal Adenocarcinoma (Caco-2), Human Ovarian Sarcoma (Skov-3) cancer cell lines, and Human Dermal Fibroblast (HDF) healthy cell line). It has been observed that they have a suppressive effect on the proliferation of cancerous cell lines. After 48 h of treatment with Ag-NPs, the DK-AgNPs were found to be extremely cytotoxic to the CaCo-2 cell line, inhibiting cell viability by up to 59.49% at a concentration of 50 g mL^-1. It was found that the viability was inversely related to the DK-AgNP concentration. The biosynthesized AgNPs had dose-dependent anticancer efficacy. Because of the high concentration of bioactive chemicals in Diospyros kaki, it may be employed as a biological resource in medicinal applications. DK-AgNPs were shown to be an effective antibacterial agent as well as a prospective anticancer agent. The results provide a potential approach for the biogenic production of DK-AgNPs utilizing D. kaki aqueous leaf extract.

Prospects of Using Gum Arabic Silver Nanoparticles in Toothpaste to Prevent Dental Caries

There is growing interest in the use of green synthesized silver nanoparticles (AgNPs) to control and prevent dental diseases. The incorporation of green synthesized AgNPs into dentifrices to reduce pathogenic oral microbes is motivated by their presumed biocompatibility and broad-spectrum antimicrobial activity. In the present study, gum arabic AgNPs (GA-AgNPs) were formulated into a toothpaste (TP) using a commercial TP at a non-active concentration, to produce GA-AgNPs_TP. The TP was selected after evaluating the antimicrobial activity of four commercial TPs 1-4 on selected oral microbes using agar disc diffusion and microdilution assays. The less active TP-1 was then used in the formulation of GA-AgNPs_TP-1; thereafter, the antimicrobial activity of GA-AgNPs_0.4g was compared to GA-AgNPs_TP-1. The cytotoxicity of GA-AgNPs_0.4g and GA-AgNPs_TP-1 was also assessed on the buccal mucosa fibroblast (BMF) cells using the MTT assay. The study demonstrated that antimicrobial activity of GA-AgNPs_0.4g was retained after being combined with a sub-lethal or inactive concentration of TP-1. The non-selective antimicrobial activity and cytotoxicity of both GA-AgNPs_0.4g and GA-AgNPs_TP-1 was demonstrated to be time and concentration dependent. These activities were instant, reducing microbial and BMF cell growth in less than one hour of exposure. However, the use of dentifrice commonly takes 2 min and rinsed off thereafter, which could prevent damage to the oral mucosa. Although, GA-AgNPs_TP-1 has a good prospect as a TP or oral healthcare product, more studies are required to further improve the biocompatibility of this formulation.

The Effect of Cytotoxicity and Antimicrobial of Synthesized CuO NPs from Propolis on HEK-293 Cells and Lactobacillus acidophilus

Background

Drug resistance is currently possible anywhere in the world. Due to the discovery of antimicrobials, medicine, and health have made tremendous advances over the past several decades.

Aim

This research evaluated the antimicrobial and cytotoxicity effects of green synthesis of copper oxide nanoparticles (CuO NPs) on Lactobacillus acidophilus and human embryonic kidney 293 cells (HEK). Method and Materials. Propolis was sampled and extracted. Green synthesis of CuO NPs was synthesized and characterized using SEM, TEM, DLS, BET, and zeta potential methods. L. acidophilus (ATCC 4356) was used, and the antimicrobial tests were carried out at different concentrations (10≥ mg/ml). Moreover, the cytotoxicity was evaluated using an MTT assay on human embryonic kidney 293 cells (HEK).

Results

Synthesized CuO NPs using propolis extracts from Khalkhal (sample 1) and Gillan (sample 2) showed -13.2 and -14.4 mV, respectively. The hydrodynamic sizes of well-dispersed samples 1 and 2 were 3124.9 nm and 1726.7 nm, respectively. According to BET analysis, samples 1 and 2 had 5.37 and 8.45 m²/g surface area, respectively. The surface area was decreased due to the addition of propolis extract, and the pore size was increased. CuO NPs of samples 1 and 2 were visible on SEM images with diameters ranging from 75 to 145 nm and 120 to 155 nm, respectively. Based on TEM analysis, the size of CuO particles was increased in samples 1 and 2. CuO NPs particles had narrow size distributions with evenly dispersed NPs on all sides. The cell viability of the CuO NPs of samples 1 and 2 after 24, 48, and 72 hours was greater than 50%. As a result of the MIC and MBC tests, it was determined that samples 1 and 2 had the same effect against L. acidophilus (0.0024 mg/ml). Biofilm formation and degradation of sample 1 were more efficient against L. acidophilus.

Conclusion

There was no evidence of cytotoxicity in the samples. In addition, results showed that the green synthesized CuO NPs from Khalkhal propolis were effective against L. acidophilus. Thus, the green synthesized CuO NPs from Khalkhal propolis were the best candidates for clinical application.

Ahmed E, Battah B, Abd Ellah NH, Zanetti S, Donadu MG. Nanotechnology as a Promising Approach to Combat Multidrug Resistant Bacteria: A Comprehensive Review and Future Perspectives

The wide spread of antibiotic resistance has been alarming in recent years and poses a serious global hazard to public health as it leads to millions of deaths all over the world. The wide spread of resistance and sharing resistance genes between different types of bacteria led to emergence of multidrug resistant (MDR) microorganisms. This problem is exacerbated when microorganisms create biofilms, which can boost bacterial resistance by up to 1000-fold and increase the emergence of MDR infections. The absence of novel and potent antimicrobial compounds is linked to the rise of multidrug resistance. This has sparked international efforts to develop new and improved antimicrobial agents as well as innovative and efficient techniques for antibiotic administration and targeting. There is an evolution in nanotechnology in recent years in treatment and prevention of the biofilm formation and MDR infection. The development of nanomaterial-based therapeutics, which could overcome current pathways linked to acquired drug resistance, is a hopeful strategy for treating difficult-to-treat bacterial infections. Additionally, nanoparticles' distinct size and physical characteristics enable them to target biofilms and treat resistant pathogens. This review highlights the current advances in nanotechnology to combat MDR and biofilm infection. In addition, it provides insight on development and mechanisms of antibiotic resistance, spread of MDR and XDR infection, and development of nanoparticles and mechanisms of their antibacterial activity. Moreover, this review considers the difference between free antibiotics and nanoantibiotics, and the synergistic effect of nanoantibiotics to combat planktonic bacteria, intracellular bacteria and biofilm. Finally, we will discuss the strength and limitations of the application of nanotechnology against bacterial infection and future perspectives.

Advanced materials and technologies for oral diseases

Oral disease, as a class of diseases with very high morbidity, brings great physical and mental damage to people worldwide. The increasing burden and strain on individuals and society make oral diseases an urgent global health problem. Since the treatment of almost all oral diseases relies on materials, the rapid development of advanced materials and technologies has also promoted innovations in the treatment methods and strategies of oral diseases. In this review, we systematically summarized the application strategies in advanced materials and technologies for oral diseases according to the etiology of the diseases and the comparison of new and old materials. Finally, the challenges and directions of future development for advanced materials and technologies in the treatment of oral diseases were refined. This review will guide the fundamental research and clinical translation of oral diseases for practitioners of oral medicine.

PVA/Chitosan Thin Films Containing Silver Nanoparticles and Ibuprofen for the Treatment of Periodontal Disease

Local delivery of drugs or antimicrobial agents is a suitable approach in the management of periodontitis when the infection is localized deep in the pockets and does not adequately respond to mechanical debridement and/or systemic antibiotic treatment. In this context, the objective of this study was to prepare new biocomposite films with antimicrobial, anti-inflammatory, and good mechanical properties to be applied in periodontal pockets. The composite film is eco-friendly synthesized from poly(vinyl alcohol) (PVA) cross-linked with oxidized chitosan (OxCS). Silver nanoparticles (AgNps) were inserted during film synthesis by adding freshly chitosan-capped AgNps colloidal solution to the polymer mixture; the addition of AgNps up to 1.44 wt.% improves the physico-chemical properties of the film. The characterization of the films was performed by FT-IR, atomic mass spectrometry, X-ray spectroscopy, and SEM. The films displayed a high swelling ratio (162%), suitable strength (1.46 MPa), and excellent mucoadhesive properties (0.6 N). Then, ibuprofen (IBF) was incorporated within the best film formulation, and the IBF-loaded PVA/OxCS-Ag films could deliver the drug in a sustained manner up to 72 h. The biocomposite films have good antimicrobial properties against representative pathogens for oral cavities. Moreover, the films are biocompatible, as demonstrated by in vitro tests on HDFa cell lines.

Antimicrobial Effects of Gum Arabic-Silver Nanoparticles against Oral Pathogens

Dental caries is considered one of the most prevalent oral diseases worldwide, with a high rate of morbidity among populations. It is a chronic infectious disease with a multifactorial etiology that leads to the destruction of the dental tissues. Due to their antimicrobial, anti-inflammatory, antifungal, and antioxidant properties; silver nanoparticles (AgNPs) are incorporated in dental products to help prevent infectious oral diseases. In this study, the antimicrobial effects of AgNPs synthesized using Gum Arabic extracts (GAE) were examined. The GA-AgNPs were synthesized and characterized using ultraviolet-visible (UV-Vis) spectrophotometer, dynamic light scattering (DLS), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. The antimicrobial activity of the GA-AgNPs was evaluated on Streptococcus sanguinis (S. sanguinis), Streptococcus mutans (S. mutans), Lactobacillus acidophilus (L. acidophilus), and Candida albicans (C. albicans) using agar disc diffusion and microdilution assays. The antibiofilm of GA-AgNPs was evaluated on the surface of human tooth enamel that had been exposed to S. mutans with and without the GA-AgNPs using scanning electron microscopy (SEM). GA-AgNPs were spherical in shape with a particle size distribution between 4 and 26 nm. The GA-AgNPs exhibited antimicrobial activity against all the tested oral microbes, with GA-AgNPs_0.4g having higher antimicrobial activity. The GA-AgNPs_0.4g inhibited S. mutans adhesion and biofilm formation on the surface of the tooth enamel. Therefore, this study supports the prospective implementation of the plant extract-mediated AgNPs in dental healthcare.

Metal and Metal Oxide Nanomaterials for Fighting Planktonic Bacteria and Biofilms: A Review Emphasizing on Mechanistic Aspects

The misuse and mismanagement of antibiotics have made the treatment of bacterial infections a challenge. This challenge is magnified when bacteria form biofilms, which can increase bacterial resistance up to 1000 times. It is desirable to develop anti-infective materials with antibacterial activity and no resistance to drugs. With the rapid development of nanotechnology, anti-infective strategies based on metal and metal oxide nanomaterials have been widely used in antibacterial and antibiofilm treatments. Here, this review expounds on the state-of-the-art applications of metal and metal oxide nanomaterials in bacterial infective diseases. A specific attention is given to the antibacterial mechanisms of metal and metal oxide nanomaterials, including disrupting cell membranes, damaging proteins, and nucleic acid. Moreover, a practical antibiofilm mechanism employing these metal and metal oxide nanomaterials is also introduced based on the composition of biofilm, including extracellular polymeric substance, quorum sensing, and bacteria. Finally, current challenges and future perspectives of metal and metal oxide nanomaterials in the anti-infective field are presented to facilitate their development and use.

Optimization of environmental factors in a dual in vitro biofilm model of Candida albicans-Streptococcus mutans

The biofilm formation of Streptococcus mutans-Candida albicans is an important virulence factor for dental caries. The purpose of this study was to determine the effect of some environmental conditions on the biofilm formation like inoculation concentration, temperature, sugar, amino acid, metal ions and saliva, and then establish a persistent in vitro biofilm model for further research. Based on the single factor experiment, the factors participating in the biofilm formation including sugar, inoculation concentration, and saliva increased the biofilm mass, while amino acid, metal ions, temperatures reduced biofilm mass. Optimal conditions for biofilm formation were the inoculation dosage of S. mutans and C. albicans of 10⁸ and 10⁷ , respectively, the addition of 0·3 g l^-1 sucrose and sterile saliva. These results contribute to a deep understanding of the factors involved in oral biofilm formation of the important cariogenic pathogen S. mutans and the opportunistic pathogen C. albicans to study better for biofilm and promote the design of new therapeutic approaches. The present research also provides a model for evaluating the therapeutic potential for drugs in the future.

Insight into the antibacterial resistance of graphdiyne functionalized by silver nanoparticles

OBJECTIVES

Silver nanoparticles (AgNPs) tend to aggregate spontaneously due to larger surface-to-volume ratio, which causes decreased antibacterial activity and even enhanced antimicrobial resistance (AMR). Here, we aim to improve the stability of AgNPs by employing a growth anchor graphdiyne (GDY) to overcome these shortcomings.

MATERIALS AND METHODS

Bacillus subtilis and Escherichia coli were selected to represent gram-positive and gram-negative bacteria, respectively. Transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM)-EDS mapping and inductively coupled plasma mass spectrometry (ICP-MS) were carried out to characterize the physiochemical properties of materials. The antimicrobial property was determined by turbidimetry and plate colony-counting methods. The physiology of bacteria was detected by SEM and confocal imaging, such as morphology, reactive oxygen species (ROS) and cell membrane.

RESULTS

We successfully synthesized a hybrid graphdiyne @ silver nanoparticles (GDY@Ag) by an environment-friendly approach without any reductants. The hybrid showed high stability and excellent broad-spectrum antibacterial activity towards both gram-positive and gram-negative bacteria. It killed bacteria through membrane destruction and ROS production. Additionally, GDY@Ag did not induce the development of the bacterial resistance after repeated exposure.

CONCLUSIONS

GDY@Ag composite combats bacteria by synergetic action of GDY and AgNPs. Especially, GDY@Ag can preserve its bacterial susceptibility after repeated exposure compared to antibiotics. Our findings provide an avenue to design innovative antibacterial agents for effective sterilization.

Characteristics of wastewater originating from dental practices using predominantly mercury-free dental materials

Dental materials are currently undergoing a revolution. Mercury use, including traditional amalgam (mercury-containing) material used in dental fillings, is now being widely regulated under the Minamata convention, and dental amalgam is currently being replaced by resin formulations in dentistry. These resin-based materials can be tuned to offer varying material properties by incorporation of a range of nano- and micro-particle based 'fillers' for different dental properties and applications. However, these innovations may have a concomitant effect on the waste streams associated with common dental applications, in particular the potential for higher concentrations of novel micro- and nanomaterials within wastewater streams, and a potential route for novel nanomaterials into the wider Environment. These new materials may also mean that wastewater filtering apparatus commonly deployed at present, such as amalgam separators, may be less efficient or insufficient to capture these new filler materials in dental facility wastewater. In this work, we analyse dental wastewater streams from three dental facilities in Ireland with differing amalgam separators in place. The potential overall toxicity, particulate load and physicochemical properties are analysed. The overall risk posed by these new materials is also discussed.

The Potential Application of Green-Synthesized Metal Nanoparticles in Dentistry: A Comprehensive Review

Orodental problems have long been managed using herbal medicine. The development of nanoparticle formulations with herbal medicine has now become a breakthrough in dentistry because the synthesis of biogenic metal nanoparticles (MNPs) using plant extracts can address the drawbacks of herbal treatments. Green production of MNPs such as Ag, Au, and Fe nanoparticles enhanced by plant extracts has been proven to be beneficial in managing numerous orodental disorders, even outperforming traditional materials. Nanostructures are utilized in dental advances and diagnostics. Oral disease prevention medicines, prostheses, and tooth implantation all employ nanoparticles. Nanomaterials can also deliver oral fluid or pharmaceuticals, treating oral cancers and providing a high level of oral healthcare. These are also found in toothpaste, mouthwash, and other dental care products. However, there is a lack of understanding about the safety of nanomaterials, necessitating additional study. Many problems, including medication resistance, might be addressed using nanoparticles produced by green synthesis. This study reviews the green synthesis of MNPs applied in dentistry in recent studies (2010–2021).

Multifarious global flora fabricated phytosynthesis of silver nanoparticles: a green nanoweapon for antiviral approach including SARS-CoV-2

The progressive research into the nanoscale level upgrades the higher end modernized evolution with every field of science, engineering, and technology. Silver nanoparticles and their broader range of application from nanoelectronics to nano-drug delivery systems drive the futuristic direction of nanoengineering and technology in contemporary days. In this review, the green synthesis of silver nanoparticles is the cornerstone of interest over physical and chemical methods owing to its remarkable biocompatibility and idiosyncratic property engineering. The abundant primary and secondary plant metabolites collectively as multifarious phytochemicals which are more peculiar in the composition from root hair to aerial apex through various interspecies and intraspecies, capable of reduction, and capping with the synthesis of silver nanoparticles. Furthermore, the process by which intracellular, extracellular biological macromolecules of the microbiota reduce with the synthesis of silver nanoparticles from the precursor molecule is also discussed. Viruses are one of the predominant infectious agents that gets faster resistance to the antiviral therapies of traditional generations of medicine. We discuss the various stages of virus targeting of cells and viral target through drugs. Antiviral potential of silver nanoparticles against different classes and families of the past and their considerable candidate for up-to-the-minute need of complete addressing of the fulminant and opportunistic global pandemic of this millennium SARS-CoV2, illustrated through recent silver-based formulations under development and approval for countering the pandemic situation.

Graphical abstract

Plant Extract-Synthesized Silver Nanoparticles for Application in Dental Therapy

Oral diseases are the most common non-communicable diseases in the world, with dental caries and periodontitis causing major health and social problems. These diseases can progress to systematic diseases and cause disfigurement when left untreated. However, treatment of oral diseases is among the most expensive treatments and often focus on restoration of form and function. Caries prevention has traditionally relied on oral hygiene and diet control, among other preventive measures. In this paper, these measures are not disqualified but are brought into a new context through the use of nanotechnology-based materials to improve these conventional therapeutic and preventive measures. Among inorganic nanomaterials, silver nanoparticles (AgNPs) have shown promising outcomes in dental therapy, due to their unique physicochemical properties and enhanced anti-bacterial activities. As such, AgNPs may provide newer strategies for treatment and prevention of dental infections. However, numerous concerns around the chemical synthesis of nanomaterials, which are not limited to cost and use of toxic reducing agents, have been raised. This has inspired the green synthesis route, which uses natural products as reducing agents. The biogenic AgNPs were reported to be biocompatible and environmentally friendly when compared to the chemically-synthesized AgNPs. As such, plant-synthesized AgNPs can be used as antimicrobial, antifouling, and remineralizing agents for management and treatment of dental infections and diseases.

Green synthesis of silver nanoparticles and evaluation of their anti-bacterial activities: use of Aloe barbadensis miller and Ocimum tenuiflorum leaf extracts

The presence of various phytochemicals makes the leaf extract-based green synthesis advantageous to other conventional methods, as it facilitates the production of non-toxic by-product. In the present study, leaf extracts from two different plants: Aloe barbadensis miller and Ocimum tenuiflorum, were used to synthesise Ag nanoparticles. The absorbance at 419-432 nm from UV-visible spectroscopy indicates the formation of Ag in the synthesised samples. The effect of precursors’ concentration on the stability, size and shape of the synthesised samples has also been investigated at constant heating temperature, stirring time, and the pH of the solution. The TEM results showed that all the synthesised samples of nanoparticles demonstrated stability with a size range of 7-70 and 9-48 nm with Aloe barbadensis miller and Ocimum tenuiflorum leaf extracts, respectively. The formation of smaller Ag nanoparticles due to utilisation of different precursor concentration and leaf extracts was also explained. The synthesised samples’ anti-bacterial activity was examined against the pathogens, Bacillus subtilis, Staphylococcus aureus, and Escherichia coli. In general, the green synthesis approach established a prospective for developing highly stable Ag nanoparticles with rigid particle shape/size distribution from different leaf extracts for the development of better anti-bacterial agents.

Green Synthesis of Copper Nano-Drug and Its Dental Application upon Periodontal Disease-Causing Microorganisms

Dental pathogens lead to chronic diseases like periodontitis, which causes loss of teeth. Here, we examined the plausible antibacterial efficacy of copper nanoparticles (CuNPs) synthesized using Cupressus macrocarpa extract (CME) against periodontitis-causing bacteria. The antimicrobial properties of CME-CuNPs were then assessed against oral microbes (M. luteus. B. subtilis, P. aerioginosa) that cause periodontal disease and were identified using morphological/ biochemical analysis, and 16S-rRNA techniques. The CME-CuNPs were characterized, and accordingly, the peak found at 577 nm using UV-Vis spectrometer showed the formation of stable CME-CuNPs. Also, the results revealed the formation of spherical and oblong monodispersed CME-CuNPs with sizes ranged from 11.3 to 22.4 nm. The FTIR analysis suggested that the CME contains reducing agents that consequently had a role in Cu reduction and CME-CuNP formation. Furthermore, the CME-CuNPs exhibited potent antimicrobial efficacy against different isolates which was superior to the reported values in literature. The antibacterial efficacy of CME-CuNPs on oral bacteria was compared to the synergistic solution of clindamycin with CME-CuNPs. The solution exhibited a superior capacity to prevent bacterial growth. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and fractional inhibitory concentration (FIC) of CME-CuNPs with clindamycin recorded against the selected periodontal disease-causing microorganisms were observed between the range of 2.6-3.6 μg/ml, 4-5 μg/ml and 0.312-0.5, respectively. Finally, the synergistic antimicrobial efficacy exhibited by CME-CuNPs with clindamycin against the tested strains could be useful for the future development of more effective treatments to control dental diseases.

A bimetallic load-bearing bioceramics of TiO2 @ ZrO2 integrated polycaprolactone fibrous tissue construct exhibits anti bactericidal effect and induces osteogenesis in MC3T3-E1 cells

Bioactive mesoporous binary metal oxide nanoparticles allied with polymeric scaffolds can mimic natural extracellular matrix because of their self-mineralized functional matrix. Herein, we developed fibrous scaffolds of polycaprolactone (PCL) integrating well-dispersed TiO₂@ZrO₂ nanoparticles (NPs) via electrospinning for a tissue engineering approach. The scaffold with 0.1 wt% of bioceramic (TiO₂@ZrO₂) shows synergistic effects on physicochemical and bioactivity suited to stem cell attachment/proliferation. The bioceramics-based scaffold shows excellent antibacterial activity that can prevent implant-associated infections. In addition, the TiO₂@ZrO₂ in scaffold serves as a stem cell microenvironment to accelerate cell-to-cell interactions, including cell growth, morphology/orientation, differentiation, and regeneration. The NPs in PCL exert superior biocompatibility on MC3T3-E1 cells inducing osteogenic differentiation. The ALP activity and ARS staining confirm the upregulation of bone-related proteins and minerals suggesting the scaffolds exhibit osteoinductive abilities and contribute to bone cell regeneration. Based on this result, the bimetallic oxide could become a novel bone ceramic tailor TiO₂@ZrO₂ composite tissue-construct and keep potential nanomaterials-based scaffold for bone tissue engineering strategy.

Nanoparticles in Dentistry: A Comprehensive Review

In recent years, nanoparticles (NPs) have been receiving more attention in dentistry. Their advantageous physicochemical and biological properties can improve the diagnosis, prevention, and treatment of numerous oral diseases, including dental caries, periodontal diseases, pulp and periapical lesions, oral candidiasis, denture stomatitis, hyposalivation, and head, neck, and oral cancer. NPs can also enhance the mechanical and microbiological properties of dental prostheses and implants and can be used to improve drug delivery through the oral mucosa. This paper reviewed studies from 2015 to 2020 and summarized the potential applications of different types of NPs in the many fields of dentistry.

Silver Nanoparticles Conjugated with Contact Lens Solutions May Reduce the Risk of Acanthamoeba Keratitis

Acanthamoeba keratitis (AK), a severe sight-threatening corneal infection, has become a significant medical problem, especially among contact lens wearers. The disease manifests as eye pain, congestion, blurred vision, lachrymation, and ring-shaped infiltrates of the cornea, and can lead to permanent blindness. Inappropriate habits of contact lens users may result in an increased risk of AK infection. The anti-amoebic efficiency of popular multipurpose contact lens solutions is insufficient to reduce this risk. An effective and non-toxic therapy against AK has not yet been developed. The prevention of AK is crucial to reduce the number of AK infections. Nanoparticles are known to be active agents against bacteria, viruses, and fungi and were also recently tested against protozoa, including Acanthamoeba spp. In our previous studies, we proved the anti-amoebic and anti-adhesive activity of silver nanoparticles against Acanthamoeba castellanii. The aim of this study is to evaluate the activity, cytotoxicity, and anti-adhesive properties of silver nanoparticles conjugated with five commonly used multipurpose contact lens solutions against the Acanthamoeba castellanii NEFF strain. The obtained results show a significant increase in anti-amoebic activity, without increasing the overall cytotoxicity, of Solo Care Aqua and Opti Free conjugated with nanoparticles. The adhesion of Acanthamoeba trophozoites to the contact lens surface is also significantly reduced. We conclude that low concentrations of silver nanoparticles can be used as an ingredient in contact lens solutions to decrease the risk of Acanthamoeba keratitis infection.

Influence of the new formulation based on silver alginate microcapsules loaded with tannic acid on the microcirculation of the experimental periodontitis in rats

The microvascular changes caused by disorders of host immune response to oral microorganisms resulting in long-lasting inflammation of gums play a critical role in the periodontal lesion in the pathogenesis of chronic periodontitis. Current strategies of non-surgical periodontal therapy are aimed at the attainment of anti-inflammatory effects. We hypothesized that the usage of the microencapsulated form of anti-inflammatory substances with vasoactive effects could enhance the efficiency of the therapy by the prolonged release of active components. The prepared suspension of silver-alginate microcapsules loaded with tannic acid in the hydrogel was applied in vivo to the experimental model of periodontitis in rats induced by a ligature. The effect of this formulation was assessed by monitoring changes in local microcirculation performed by the Laser Doppler Flowmetry (1 and 24 h after application of hydrogel on intact gums and 21-days after the start of periodontitis' modeling). Application of the hydrogel containing multicomponent microcapsules to the affected area of gums allows correction of inflammatory microcirculatory disorders in model periodontitis. Immobilization of tannic acid into microcapsules allows increasing the correction of the following parameters: perfusion disorders, neurogenic tone of arterioles, myogenic tone of precapillary sphincters, as well as a venous outflow in the microvasculature of the gums. The hydrogel containing multicomponent microcapsules reduces the vascular inflammatory response in the model of periodontitis. Loading of silver-alginate microcapsules with tannic acid enhances the efficiency of microvascular disorders' correction in the model of periodontitis that suggests the prospects for application of this drug delivery system for non-surgical treatment of periodontitis.

Known data on the effectiveness of silver nano particles on root canal disinfection

The goal of endodontic treatment is the debridement and removal of the microbial ecosystem associated with the disease process. The need for root canal disinfectants increases especially in those cases where infection is resistant to the regular treatment and the outcome of endodontic therapy is often compromised. Therefore, it is of interest to document the known effectiveness of silver nanoparticle based root canal disinfectants with other root canal disinfectants on microbial load reduction during root canal disinfection. Known data shows that the overall risk of bias for the selected studies was moderate. Silver nanoparticle based root canal disinfectants showed superior reduction of microbial counts in majority of the studies. This data is limited to vitro studies with no clinical information to validate the use of antimicrobial properties of silver nanoparticles used as root canal disinfectant.

Phytoassisted synthesis of magnesium oxide nanoparticles from Pterocarpus marsupium rox.b heartwood extract and its biomedical applications

BACKGROUND

Unlike chemical techniques, the combination of metal oxide nanoparticles utilizing plant concentrate is a promising choice. The purpose of this work was to synthesize magnesium oxide nanoparticles (MgO-NPs) utilizing heartwood aqueous extract of Pterocarpus marsupium. The heartwood extract of Pterocarpus marsupium is rich in polyphenolic compounds and flavonoids that can be used as a green source for large-scale, simple, and eco-friendly production of MgO-NPs. The phytoassisted synthesis of MgO is characterized by UV-Visible spectroscopy, X-ray diffraction (XRD), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) with EDS (energy dispersive X-ray spectroscopy), and transmission electron microscopy (TEM).

RESULTS

The formation of MgO-NPs is confirmed by a visual color change from colorless to dark brown and they displayed a wavelength of 310 nm in UV-Spectrophotometry analysis. The crystalline nature of the obtained biosynthesized nanoparticles are revealed by X-ray diffraction analysis. SEM results revealed the synthesized magnesium oxide nanoparticles formed by this cost-effective method are spherically shaped with an average size of < 20 nm. The presence of magnesium and oxygen were confirmed by the EDS data. TEM analysis proved the spherical shape of the nanoparticles with average particle size of 13.28 nm and SAED analysis confirms the crystalline nature of MgO-NPs. FT-IR investigation confirms the existence of the active compounds required to stabilize the magnesium oxide nanoparticles with hydroxyl and carboxyl and phenolic groups that act as reducing, stabilizing, and capping agent. All the nanoparticles vary in particle sizes between 15 and 25 nm and obtained a polydispersity index value of 0.248. The zeta-potential was measured and found to be - 2.9 mV. Further, MgO-NPs were tested for antibacterial action against Staphylococcus aureus (Gram-positive bacteria) and Escherichia coli (Gram-negative bacteria) by minimum inhibitory concentration technique were found to be potent against both the bacteria. The blended nanoparticles showed good antioxidant activity examined by the DPPH radical scavenging method, showed good anti-diabetic activity determined by alpha-amylase inhibitory activity, and displayed strong anti-inflammatory activity evaluated by the albumin denaturation method.

CONCLUSIONS

The investigation reports the eco-friendly, cost-effective method for synthesizing magnesium oxide nanoparticles from Pterocarpus marsupium Rox.b heartwood extract with biomedical applications.

Sustained-release delivery of antimicrobial drugs for the treatment of periodontal diseases: Fantasy or already reality?

Periodontal diseases are prevalent in humans. Conventional means of combating these diseases involve basic oral hygiene, mostly toothbrushing, use of mouthwashes, and flossing. Supplementary means of treatment, either clinical or pharmaceutical, are often necessary. The use of sustained-release delivery systems, applied locally to the periodontal pocket, seems to be one feasible approach: local sustained-release delivery of antibacterial agents to treat periodontal diseases is conceivable. The use of local (intrapocket) sustained-release delivery systems has numerous clinical, pharmacologic, and toxicologic advantages over conventional treatments for periodontal diseases. Sustained-release technology has been proven to be effective over the last few decades. Films, gels, and fibers are the three main classical intrapocket pharmaceutical delivery systems. Research today is more focused on improving drug delivery, and less on introducing new drugs. New approaches, eg, those making use of nanotechnology, are emerging for local drug-delivery systems. The local sustained-release delivery system concept is innovative and a few products are already commercially available.

Therapeutic Use of Silver Nanoparticles in the Prevention and Arrest of Dental Caries

Dental caries is one of the major diseases of the oral cavity affecting humans worldwide. Different alternatives have been used for its control, but its incidence and prevalence are still high. On the other hand, silver has been used for centuries due to its antimicrobial properties. With advances in nanotechnology, the use and research in nanomaterials has increased, recently, and silver nanoparticles have become an essential part of the dental practice, giving materials physical and chemical improvements in their properties, used for their antibacterial capacity preventing and arresting dental caries. The objective of this review was to examine the use of silver nanoparticles, in the treatment of dental caries in the remineralization of teeth hard tissues, as well as the antimicrobial potential, cytotoxicity, and long-term effectiveness.

Fabrication and characterization of ZrO2 incorporated SiO2-CaO-P2O5 bioactive glass scaffolds

Sol-gel chemistry offers a flexible, widely accepted methodology that enables the creation of a new generation of bioactive glass (BG). In the current study, a sol-gel method was used to synthesize ZrO₂ incorporated 56SiO₂-34CaO-10P₂O₅ mol% bioactive glass. The highly crystalline structure was composed of small zirconium oxide nanoparticles (ZrO₂) of less than 200 nm in size. It was successfully fabricated using a hydrothermal method. Polyurethane foam (PU) was selected to fabricate a highly porous BG-ZrO₂ scaffold using a foam replica technique. The physicochemical, morphological properties of the BG-ZrO₂ compositions were evaluated using X-ray diffraction (XRD), Fourier transforms infrared (FTIR), thermo-gravimetric analysis (TGA), transmission electron microscope (TEM) and scanning electron microscope (SEM) with energy dispersive spectroscopy (EDS). In-vitro degradation analysis of the BG-ZrO₂ scaffolds was performed after immersion of the samples in simulated body fluid (SBF). The incorporation of ZrO₂ nanoparticles into the bioactive glass matrix enhances both the mechanical strength and thermal stability. Since the novel formed BG-ZrO₂ scaffolds possesses respectable antibacterial properties against some bacterial strains, this renders it an ideal tissue engineering substitute, capable of reducing failure rates in implants.

Use of Silver Nanomaterials for Caries Prevention: A Concise Review

Objective

The aim of this concise review is to summarize the use of silver nanomaterials for caries prevention.

Methods

Two researchers independently performed a literature search of publications in English using Embase, Medline, PubMed, and Scopus databases. The keywords used were (silver nanoparticles OR AgNPs OR nano silver OR nano-silver) AND (caries OR tooth decay OR remineralisation OR remineralization). They screened the title and abstract to identify potentially eligible publications. They then retrieved the full texts of the identified publications to select original research reporting silver nanomaterials for caries prevention.

Results

The search identified 376 publications, and 66 articles were included in this study. The silver nanomaterials studied were categorized as resin with silver nanoparticles (n=31), silver nanoparticles (n=21), glass ionomer cement with silver nanoparticles (n=7), and nano silver fluoride (n=7). Most (59/66, 89%) studies investigated the antibacterial properties, and they all found that silver nanomaterials inhibited the adhesion and growth of cariogenic bacteria, mainly Streptococcus mutans. Although silver nanomaterials were used as anti-caries agents, only 11 (11/66, 17%) studies reported the effects of nanomaterials on the mineral content of teeth. Eight of them are laboratory studies, and they found that silver nanomaterials prevented the demineralization of enamel and dentin under an acid or cariogenic biofilm challenge. The remaining three are clinical trials that reported that silver nanomaterials prevented and arrested caries in children.

Conclusion

Silver nanoparticles have been used alone or with resin, glass ionomer, or fluoride for caries prevention. Silver nanomaterials inhibit the adhesion and growth of cariogenic bacteria. They also impede the demineralization of enamel and dentin.

Silver Nanoparticles as a Novel Potential Preventive Agent against Acanthamoeba Keratitis

Free living, cosmopolitan amoebae from Acanthamoeba genus present a serious risk to human health. As facultative human parasites, these amoebae may cause Acanthamoeba keratitis (AK). Acanthamoeba keratitis is a severe, vision-threatening corneal infection with non-specific symptoms. The number of reported AK cases worldwide has been increasing every year. Moreover, 90% of Acanthamoeba keratitis cases are related to contact lens use. Wearing and storage contact lenses not in accordance with the physicians and manufacturers recommendations are the primary key risk factors of this disease. Amoebae can easily adhere to the contact lens surface and transmit to the corneal epithelium. Preventing amoebae adhesion to the contact lens surface could significantly decrease the number of AK infections. Until now, the effective therapy against AK is still under development. Currently proposed therapies are mainly limited to the chlorhexidine digluconate combined with propamidine isethionate or hexamidine applications, which are insufficient and very toxic to the eye. Due to lack of effective treatment, looking for new potential preventive agents is crucial to decrease the number of Acanthamoeba keratitis infections, especially among contact lens users. Nanoparticles have been already included in several novel therapies against bacteria, viruses, fungi, and protist. However, their anti-amoebic potential has not been fully tested yet. The aim of this study was to assess silver nanoparticles (AgNPs) and platinum nanoparticles (PtNPs) anti-amoebic activity and influence on the amoebae adhesion to the surface of four different groups of contact lenses-classified according to the Food and Drugs Administration (FDA) guidelines. The obtained results show that both tested nanoparticles were effective against Acanthamoeba trophozoites and decreased the amoebae adhesion to the contact lens surface. AgNPs showed better anti-amoebic activity to cytotoxicity dependence and reduced amoebae adhesion in a wider spectrum of the tested contact lenses. Our studies also confirmed that ionization next to hydration of the contact lens material is a crucial parameter influencing the Acanthamoeba adhesion to the contact lens surface. In conclusion, silver nanoparticles might be considered as a novel preventive agent against Acanthamoeba keratitis infection.

New avenues of controlling microbial infections through anti-microbial and anti-biofilm potentials of green mono-and multi-metallic nanoparticles: A review

Nanoparticles synthesized through the green route deserve special mention because this green technology is not only energy-efficient and cost-effective but also amenable to the environment. Various biological resources have been used for the generation of these 'green nanoparticles'. Biological wastes have also been focused in this direction thereby promoting the value of waste. Reports indicate that green nanoparticles exhibit remarkable antimicrobial activitiesboth singly as well as in combination with standard antibiotics. The current phenomenon of multi-drug resistance has resulted due to indiscriminate administration of high-doses of antibiotics followed by significant toxicity. In the face of this emergence of drug-resistant microbesthe efficacy of green nanoparticles might prove greatly beneficial. Microbial biofilm is another hurdle in the effective treatment of diseases as the microorganismsbeing embedded in the meshwork of the biofilmevade the antimicrobial agents. Nanoparticles may act as a ray of hope on the face of this challenge tooas they not only destroy the biofilms but also lessen the doses of antibiotics requiredwhen administered in combination with the nanoparticles. It should be further noted that the resistance mechanisms exhibited by the microorganisms seem not that relevant for nanoparticles. The current review, to the best of our knowledgefocuses on the structures of these green nanoparticles along with their biomedical potentials. It is interesting to note how a variety of structures are generated by using resources like microbes or plants or plant products and how the structure affects their activities. This study might pave the way for further development in this arena and future work may be taken up in identifying the detailed mechanism by which 'green' synthesis empowers nanoparticles to kill pathogenic microbes.

Diamond-like carbon films over reconstructive TMJ prosthetic materials: Effects in the cytotoxicity, chemical and mechanical properties

Increasingly more young patients have been submitted to reconstruction of the Temporomandibular Joint (TMJ), so, the prostheses must to present more functional longevity.

Objective

To evaluate the effect of diamond-like carbon film (DLC) over titanium alloy (Ti6Al4V) and polyethylene (UHWPE) samples, their mechanical and chemical properties and cellular cytotoxicity.

Methods

Titanium and UHWPE specimens, with 2.5 cm in diameter and 2 mm thickness were coated through plasma enhanced chemical vapor deposition (PECVD) with DLC or DLC doped with silver (DLC-Ag). Scanning electron microscopy (SEM) morphological analysis, Energy-dispersive spectroscopy (EDS) chemical analysis, scratching test, mechanical fatigue test, surface roughness analysis, and cellular cytotoxicity were performed. Data were statistically analyzed using one-way ANOVA (p < 0.05) or two-way ANOVA and multiple comparison Tukey test.

Results

In the SEM analysis, morphological differences were observed on substrates after DLC deposition. The film chemically modified the substrate surfaces, according to the EDS analysis. The initial critical load failure occurred at 6.1 N for DLC and 9.7 N for the DLC-Ag film. The DLC film deposition over the polyethylene promoted a decrease in the polymer's damaged area after mechanical fatigue cycling. The cytotoxicity analysis demonstrated less biocompatibility in experimental groups, when compared to control, however, increased biocompatibility was observed, at 10 days, in all groups.

Conclusion

The diamond-like carbon coating enhanced the chemical and mechanical properties from substrates, however modified biological interaction course of the titanium alloy (Ti6Al4V) and polyethylene (UHWPE) samples. Parameters for film deposition remain to be improved in order to obtain best biocompatibility.