Novel green synthesis approach of Fe3O4-MSN/Ag nanocomposite using moringa oleifera extract for magnetic hyperthermia applications

Microstructures, optical, magnetic properties, and specific absorption rate of novel magnetite/mesoporous silica nanoparticles synthesized using green route for magnetic hyperthermia application

The Influence of Coating and Agglomeration on Specific Absorption Rate of Iron Oxide Nanoparticles

Nanoparticles are used across many scientific and pharmaceutical fields and are found in products that come into close contact with the human body. There is a growing need for ‘green synthesis’ of silver (Ag) nanoparticles and plant-mediated synthesis is becoming increasingly popular. The current study aimed to firstly synthesise Ag nanoparticles using fresh and freeze-dried leaves, stems and roots of the African leafy vegetable, Amaranthus dubius. The synthesised Ag nanoparticles were subsequently characterised using UV–visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) analysis and Fourier transform infrared (FTIR) spectral analysis. The bioactivity (antibacterial and antifungal) of the synthesised Ag nanoparticles was also assessed using the minimum inhibition concentration (MIC) method. The results suggest that A. dubius plant extracts can serve as environmentally benign bio-factories for the synthesis of bioactive Ag nanoparticles. However, the characteristics of these nanoparticles differed based on the organ used to prepare the extract and whether the plant material was fresh or freeze-dried. Silver nanoparticle yield was greatest in the freeze-dried and fresh leaf extracts of A. dubius. However, EDX analysis revealed nanoparticles produced using freeze-dried and fresh stem extracts to contain the most elemental Ag. Silver nanoparticles synthesised from the different plant organs all displayed a spherical shape; however, Ag nanoparticles synthesised from the stem extracts (30–35nm) were significantly larger than those synthesised from leaf and root extracts (18–21nm). FTIR analysis confirmed the presence of carbonyl groups, proteins and aldehydes on nanoparticles produced using all extract types. The Ag nanoparticles synthesised from fresh stem extracts displayed the highest antimicrobial activity compared with those synthesised from the other plant organs. Fresh stem extracts of A. dubius appear to be most suitable for biosynthesis of Ag nanoparticles, yielding the largest nanoparticles, with the highest elemental Ag content, and greatest inhibition of microbial growth.

Investigation of electrospun chitosan nanofibers reinforced with mesoporous silicon oxide decorated with silver nanoparticles in diabetic wound treatment.

The interactions of human hemoglobin with protein capped silver nanoparticles and bare silver nanoparticles were studied to understand fundamental perspectives about the biocompatibility of protein capped silver nanoparticles compared with bare silver nanoparticles. Bare silver (Ag) nanoparticles (NPs) were prepared by the chemical reduction method. High resolution transmission electron microscopy (HRTEM) analysis along with absorption at ~390 nm indicated the formation of bare Ag NPs. Protein coated Ag NPs were prepared by a green synthesis method. Absorption at ~440 nm along with ~280 nm indicated the formation of protein coated Ag NPs. The biocompatibility of the above mentioned Ag NPs was studied by interaction with human hemoglobin (Hb) protein. In presence of bare Ag NPs, the Soret band of Hb was red shifted. This revealed the distortion of iron from the heme pockets of Hb. Also, the fluorescence peak of Hb was quenched and red shifted which indicated that Hb became unfolded in the presence of bare Ag NPs. No red shift of the absorption of Soret, along with no shift and quenching of the fluorescence peak of Hb were observed in the presence of protein coated Ag NPs. A hemolysis assay suggested that protein coated Ag NPs were more biocompatible than bare one.

In this work, the silver or gold nanoparticle single‐existing and co‐existing tellurite glasses doped with Eu 3+ were prepared, and the influence of gold or silver nanoparticles on the photoluminescence of tellurite glasses doped with Eu 3+ were investigated. The photoluminescence of tellurite glasses doped with Eu 3+ was enhanced by the surface plasmon absorption of gold or silver nanoparticles, and the maximum luminescence enhancement factors caused by the silver and gold nanoparticles are 4.8 and 3.5 factors, respectively. The differentiation of luminescence enhancement mechanisms caused by the gold or silver nanoparticles was demonstrated. The enhanced luminescence mechanism of the Au nanoparticle single‐existing tellurite glasses doped with Eu 3+ was from the increasing of radiative decays rate caused by the Au nanoparticles. The excitation field enhancement caused by the Ag nanoparticles was responsible for the luminescence enhancement of the Ag single‐existing tellurite glasses doped with Eu 3+ . About 4.2‐factor luminescence enhancement was observed in the Ag and Au nanoparticle co‐existing tellurite glasses doped with Eu 3+ , which is attributed to the increasing of radiative decays rate and excitation field enhancement caused by the Au and Ag nanoparticles.

A study on the stability and green synthesis of silver nanoparticles using Ziziphora tenuior (Zt) extract at room temperature

Magnetic hyperthermia in magnetic nanoemulsions: Effects of polydispersity, particle concentration and medium viscosity

Clever combinations of different types of functional nanostructured materials will enable the development of multifunctional nanomedical platforms for multimodal imaging or simultaneous diagnosis and therapy. Mesoporous silica nanoparticles (MSNs) possess unique structural features such as their large surface areas, tunable nanometer-scale pore sizes, and well-defined surface properties. Therefore, they are ideal platforms for constructing multifunctional materials that incorporate a variety of functional nanostructured materials. In this Account, we discuss recent progress by our group and other researchers in the design and fabrication of multifunctional nanocomposite nanoparticles based on mesoporous silica nanostructures for applications to simultaneous diagnosis and therapy. Versatile mesoporous silica-based nanocomposite nanoparticles were fabricated using various methods. Here, we highlight two synthetic approaches: the encapsulation of functional nanoparticles within a mesoporous silica shell and the assembly of nanoparticles on the surface of silica nanostructures. Various nanoparticles were encapsulated in MSNs using surfactants as both phase transfer agents and pore-generating templates. Using MSNs as a scaffold, functional components such as magnetic nanoparticles and fluorescent dyes have been integrated within these systems to generate multifunctional nanocomposite systems that maintain their individual functional characteristics. For example, uniform mesoporous dye-doped silica nanoparticles immobilized with multiple magnetite nanocrystals on their surfaces have been fabricated for their use as a vehicle capable of simultaneous magnetic resonance (MR) and fluorescence imaging and drug delivery. The resulting nanoparticle-incorporated MSNs were then tested in mice with tumors. These in vivo experiments revealed that these multifunctional nanocomposite nanoparticles were delivered to the tumor sites via passive targeting. These nanocomposite nanoparticles served as successful multimodal imaging probes and also delivered anticancer drugs to the tumor site. With innumerable combinations of imaging modalities and drug delivery available within these vehicles, multifunctional nanocomposite nanoparticles provide new opportunities for clinical diagnostics and therapeutics.

The main aim of the study was to optimization and evaluation of a suitable dosage form i.e., tropical gel containing silver and gold nanoparticles which are synthesized by green synthesis as this is the rapid and better alternative to chemical synthesis. For burn injury systemic route of administration is not suitable due to damaged skin hence tropical route selected to provide controlled effects, low systemic toxicity and easy application. Silver nanoparticles were synthesized by green synthesis by use of neem leaves and gold nanoparticles by Aloe vera. Characterization was done by UV spectroscopy, particle size distribution, TEM and zeta potential. Gel was formulated by simple mixing and stirring method and evaluated for color, homogeneity, Spreadability, viscosity, in vitro release, antimicrobial study and in vivo study. In this study, the combination of Carbopol 934 P and HPMC (ratio 1:3) was found to be ideal formulation (Formulation F5) with optimum viscosity and Spread-ability i.e., 4459 cP and 5.7 gmcm/sec resp. in vitro release was found to be 98.66% in 12 hours. in vitro antimicrobial study and in vivo study on rat showed maximum effects than standard formulations. From this study it can be concluded that, tropical gel is the superior dosage form containing silver and gold nanoparticles which acts as the antimicrobial agents and is effective in treatment of burn surgery.

Abstract: Nanoparticles (NPs) are tiny particles with their dimensions ranging between1and100 nm. These are gaining cumulative attention owing to their vast use in different fields of applications. There are three main methods for synthesizing NPs; namely, physical, chemical and biological methods. Physical methods consume a lot of energy and time, require expensive vacuum systems and high temperatures and on top of all, they are not environmentally friendly. Chemical methods, in general, are expensive, increase the particle toxicity and perhaps harm human health and the environment. In addition, hazardous chemicals gather on the top of NPs and confine their applications. Therefore, green method is an alternative replacement to the traditional chemical and physical methods for synthesizing NPs. The existing phytochemicals, for instance in plant extracts, own a remarkably high ability for reducing metal ions within a short time comparing with other microorganisms, which require a longer incubation period. This study is concentrating on green synthesis of silver (Ag) NPs, owing to the significance of Ag NPs whose optical properties depend on their size and shape. In addition, Ag NPs possess numerous applications, especially in solar cells, water treatment and medicine. This review aims to highlight the remarkable growth of green synthesis of Ag NPs, in terms of publications, citations, active and productive researchers, targeting journals and the eminent countries in this regard. This review, also, is highlights the most utilized plants for producing Ag NPs in fourteen years; i.e., 2007-2021.This review, also, evaluating the most acceptable proposed mechanism for biosynthesizing Ag NPs using plant extracts. We believe that this review article will facilitate and brighten the road in front of researchers who want to initiate their study with the biosynthesis of Ag NPs from plant extracts. Keywords: Silver nanoparticles, Green synthesis, Plant extracts, Stabilizing agents, Reducing agents.

Exploiting mesoporous silica, silver and gold nanoparticles for neurodegenerative diseases treatment

The comparative effects of mesoporous silica nanoparticles and colloidal silica on inflammation and apoptosis

Mesoporous silica nanoparticles (MSNs) are among the most adaptable nanocarriers in modern pharmaceutics, characterized by a high surface area, tunable pore size, controllable morphology, and excellent biocompatibility. These qualities enable effective encapsulation, protection, and the delivery of drugs in a specific area and, therefore, MSNs are powerful platforms for the targeted and controlled delivery of drugs and theragnostic agents. Over the past ten years and within the 2021–2025 period, the advancement of MSN design has led to the creation of hybrid nanostructures into polymers, lipids, metals, and biomolecules that have yielded multifunctional carriers with enhanced stability, responsiveness, and biological activities. The current review provides a review of the synthesis methods, surface functionalization techniques, and physicochemical characterization techniques that define the next-generation MSN-based delivery systems. The particular focus is put on stimuli-responsive systems, such as redox, pH, enzyme-activated, and light-activated systems, that enable delivering drugs in a controlled and localized manner. We further provide a summary of the biomedical use of MSNs and their hybrids such as in cancer chemotherapy, gene and nucleic acid delivery, antimicrobial and vaccine delivery, and central nervous system targeting, supported by recent in vivo and in vitro studies. Important evaluations of biocompatibility, immunogenicity, degradation, and biodistribution in vivo are also provided with a focus on safety in addition to the regulatory impediments to clinical translation. The review concludes by saying that there are still limitations such as large-scale reproducibility, long-term toxicity, and standardization by the regulators, and that directions are being taken in the future in the fields of smart programmable nanocarriers, green synthesis, and sustainable manufacture. Overall, mesoporous silica and hybrid nanoparticles represent a breakthrough technology in the nanomedicine sector with potentials that are unrivaled in relation to targeted, controlled, and personalized therapeutic interventions.

Silica is presently widely used as a template for the development of various nanostructures due to its characteristic high surface area, thermal and chemical resistance, the presence of reactive silanol groups (Si–OH), and nanopores. Nontraditional nanostructures consisting of noble metals are often fabricated by depositing thin layers of metals (or their precursors) on some silica beads existing templates. A straightforward sol-gel method can be utilized for the preparation of noble metal nanoparticles and their composites via in situ-doped silica aerogels. The metal dispersion and size distribution obtained by this approach depends on the kind of metal, the reaction conditions, and the metal loading. Another approach consisted of making use of the pore channels of hexagonal mesoporous silica, as matrixes for controlling the nanoparticles size. It was demonstrated that noble metal nanoparticles could be coated with a silica shell via the reaction of citrate-stabilized gold nanoparticles and alkylaminotrimethoxysilane, followed by polymerization after the addition of a sodium silicate solution. The spherical silica nanoparticles were used as the templates of interior cores of metal nanoshells and as the templates for the deposition of the external noble metal shell layer by layer. A controlled growth of silver nanoparticles on TiO2 templates is expected in tuning the optical response of the silver–TiO2 hybrids. The growth model can explain the phenomenon of silver nanoplates lying on the small silver nanoparticles. A simple and reproducible method for the activation of monodispersed silver nanoparticles was insertion of the concentrated NaCl, NaBr, and NaI solution into the silver nanoparticle dispersion. It was also demonstrated the entrapment of thiol-coated gold particles, and believe that the technique is straightforwardly applicable also for other hydrophobically coated nanoparticles. The presence of a substrate influences the resultant frequency and bandwidth of the surface plasmon resonance and more generally its multipole distribution. By combining two different materials or different particle shapes of the same material within the same single nanostructure, new properties of the coupled system can be obtained. An interesting approach to introduce theranostic functionalities into a nanosystem is to covalently attach a metal-porphyrin chelate to mesoporous silica nanoparticles (MSNs) which are readily taken up by cells. Bioconjugates based on MSNs are used in a wide array of applications, including chemical catalysis, drug delivery, controlled release of therapeutics, and cell labeling and killing. UV-photoexcited TiO2 nanoparticles and their conjugates in aqueous solution form various reactive oxygen species, mainly highly reactive hydroxyl (OH), peroxy (HO2) radicals, and singlet oxygen, highly reactive hydroxyl radicals, electrons and superoxide ions able to deactivate of bacteria, algae, viruses and kill cancer cells.