Biomedical applications of green synthesized Nobel metal nanoparticles

3D hybrid structures based on biomimetic membranes and Caryophyllus aromaticus - "green" synthesized nano-silver with improved bioperformances

The paper describes an innovative bio-design of some hybrid nanoarchitectures containing bioartificial membranes and silver nanoparticles phytogenerated by using a natural extract Caryophyllus aromaticus (cloves) that contains many bioactive compounds. Two kinds of liposomes with and without chlorophyll a (Chla) obtained through thin film hydration method were used to achieve bio-green-generated hybrids by a simple, cost effective bottom-up approach. The characteristic peaks of CE-nAg monitored by UV-Vis absorption have firstly demonstrated the biohybrids formation. The slightly blue shift and fluorescence quenching observed by fluorescence emission spectra highlighted the formation of hybrid systems by biointeraction between lipid vesicles and silver nanoparticles. The incorporation of silver nanoparticles in lipid vesicles resulted in significant changes of FT-IR spectra of liposomes, indicating a reorganization of biomimetic membranes. All the microscopic methods (SEM, AFM and TEM) confirmed the biosynthesis of "green" AgNPs together with associated biohybrids, their spherical and quasi-spherical shapes with nano-scaled size. By TEM assay it was shown that CE-nAg are surrounded by petal like cloud structures that consist of biopolymers like proteins or polysaccharides and other phytochemicals arising from clove extract. EDS spectra confirmed the formation of phyto-nanoAg and also the presence of silver in the biohybrids. In addition, Selected Area Electron Diffraction showed characteristic polycrystalline ring patterns for a cubic structure of the clove-generated AgNPs. The hybrid materials showed efficient physical stability,i.e. ξ value of -28.0 mV (for biohybrids without Chla, BH) and of -31.7 mV (for biohybrids labelled with Chla, Chla-BH), assured by strong electrostatic repulsive forces between particles. The "green" nano-silver particles (CE-nAg) showed remarkable antioxidant activity (AA = 90.2%). The biohybrids loaded with clove-AgNPs proved to be more effective, scavenging about 98.8% of free radicals (in case of Chla-BH), and of 92.6% (in case of BH). The antibacterial effectiveness showed that green AgNPs combine in a synergistic manner the antibacterial properties of clove extract with those of silver, resulting in an enhancement of inhibition diameter, by 20%. Chla-BH proved to be more potent against Escherichia coli, than BH, exhibiting an inhibition diameter of 42 mm. Regarding the in vitro cytotoxicity against tumour cells, the CE-nAg concentration significantly influenced the cell viability, i.e. IC₅₀ was 3.6% (v/v) for HT-29 cells. Chla-BH was more effective against HT-29 cancer cells at the concentrations ranging from 0 to 18% (v/v), when the normal cells were not affected. Clove-generated AgNPs exhibited haemolytic activity against hRBCs, while the biohybrids were haemocompatible. The action mechanism on the two cell lines (mouse fibroblast L929 cells and human colorectal adenocarcinoma HT-29 cells) investigated by fluorescence microscopy demonstrated that CE-nAg killed almost all the cells (94%) through necrosis at a concentration of 33.4% (v/v). The treatment of HT-29 cells with BH resulted in: 71.5% viable cells, 19.5% apoptotic and only 9% necrotic cells, while in the case of Chla-BH treatment, only 77.5% cells were viable, 16% cells were apoptotic and 6.5% were necrotic. In this way, the developed silver-based nanoparticles can represent viable promoters to develop new biohybrids with improved features, e.g. antioxidant and antibacterial effectiveness, haemolytic activity and greater specificity towards tumour cells.

Tuber extract of Arisaema flavum eco-benignly and effectively synthesize silver nanoparticles: Photocatalytic and antibacterial response against multidrug resistant engineered E. coli QH4

Metal nanoparticles, synthesized using Phyto-constituents are the most economically and environmentally benign materials ever. Biogenic silver nanoparticles (AgNPs) from three fractions of Arisaema flavum tuber extract were synthesized and characterized by UV-visible spectroscopy, XRD (X-rays diffraction), FT-IR (Fourier transform infrared spectroscopy) TEM (transmission electron microscopy) and EDX (Energy dispersive Microscopy). XRD pattern show the face centred cubic crystalline (Fcc) structure of AgNPs. FTIR spectra confirmed the presence of different Polyphenolic compounds capping the AgNps. UV-visible spectroscopy result confirmed the presence of Ag because of the particular surface plasmon Resonance (SPR) in the area of 400-430 nm. The electron microscope studies revealed the formation of spherical AgNPs with diameter ranging from 12 nm to 20 nm. Strong signals of AgNPs were confirmed with EDX analysis. The antibacterial properties of the AgNPs prepared with various extracts were tested against multi-drug resistant bacteria. Which showed significant antibacterial activity against all the multidrug resistant bacterial strains and especially multidrug resistant engineered E.ColiQH4. AgNPs synthesized by methanolic, Ethyl Acetate and aqueous Extracts of Areseama Flavum exhibited significant Photocatalytic activity to reduce methylene blue. Small size, spherical shape and high dispersion are the key properties due to which the AgNPs are having significant biological and photocatalytic activity. To the best of our knowledge, it is the first report of biogenic AgNPs regarding antibacterial activity against multidrug resistant Engineered E.Coli QH4.

Plasma and Nanomaterials: Fabrication and Biomedical Applications

Application of plasma medicine has been actively explored during last several years. Treating every type of cancer remains a difficult task for medical personnel due to the wide variety of cancer cell selectivity. Research in advanced plasma physics has led to the development of different types of non-thermal plasma devices, such as plasma jets, and dielectric barrier discharges. Non-thermal plasma generates many charged particles and reactive species when brought into contact with biological samples. The main constituents include reactive nitrogen species, reactive oxygen species, and plasma ultra-violets. These species can be applied to synthesize biologically important nanomaterials or can be used with nanomaterials for various kinds of biomedical applications to improve human health. This review reports recent updates on plasma-based synthesis of biologically important nanomaterials and synergy of plasma with nanomaterials for various kind of biological applications.

Antifungal and antibacterial activity of densely dispersed silver nanospheres with homogeneity size which synthesized using chicory: An in vitro study

With increase in isolation of multi and extensive drug resistance hospital pathogens (MDR, XDR) in burn centers of many hospitals in the world, attempt to use nanomaterials for treatment of burn-infected patients is the focus of researches all around the world. In the present investigation silver nanospheres (Ag NSs) has been synthesized by chicory seed exudates (CSE). The various parameters influencing the mechanism of Ag NSs synthesis including temperature, concentration, pH and time were studied. Greener Ag NSs were formed when the reaction conditions were altered with respect to pH, concentration of AgNO3 and incubation temperature. Finally, we evaluated antimicrobial activity of silver nanospheres biosynthesized by chicory (Cichodrium intybus) against most prevalent burn bacteria pathogens Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii, and fungus Fusarium solani. The UV visible spectroscopy, X-Ray diffraction (XRD), dynamic light scattering (DLS) used for primary screening of physicochemical properties. The transmission electron microscopy (TEM) images showed the Ag NSs (with globular shape) with a size less than 25nm that they have the same size about 8nm (more than 97% are 8nm). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of Ag NSs against the standard strains of A. baumannii, P. aeruginosa and K. pneumonia showed a relatively high inhibitory and bactericidal activity (MIC 1.56μg/mL and MBC 3.12μg/mL) of the nanoparticles and F. solani cultures. In antifungal tests, the lowest level of zone of inhibition was observed at a concentration of 5μg/mL synthesized silver nanospheres with the 7% inhibition of growth. Ag NSs have high antimicrobial activity against three common burn bacteria pathogens and fungus F. solani. Therefore, Ag NSs can be used to prevent burn infection and for wound healing.

Biosynthesis of bimetallic and core-shell nanoparticles: their biomedical applications - a review

Recently, researchers succeeded in designing and manufacturing a new class of nanoparticles (NPs) called hybrid NPs. Among hybrid NPs, bimetallic and core-shell NPs were a revolutionary step in NPs science. A large number of green physiochemical and methods for nanostructures synthesis have been published. Eventually, physiochemical methods are either expensive or require the use of chemical compounds for the synthesis of bimetallic and core-shell nanostructures. The main challenges that scientists are facing are making the process cheaper, facile and eco-friendly efficient synthesis process. Green synthesis (biosynthesis) refers to the use of bio-resources (such as bacteria, fungi, plants or their derivatives) for the synthesis of nanostructures. The popularity of the green synthesis of nanostructures is due to their environmental friendliness and no usage of toxic materials, environmental friendliness for the synthesis or stability of nanostructure. Bimetallic and core-shell NPs have many biomedical applications such as removing heavy metals, parasitology, molecular and microbial sensor, gene carrier, single bacterial detection, oligonucleotide detection and so on. The purpose of this study is to discuss briefly the biosynthesised bimetallic and core-shell NPs, their biomedical applications.