During the past few years, silver nanoparticles (AgNPs) became one of the most investigated and explored nanotechnology-derived nanostructures, given the fact that nanosilver-based materials proved to have interesting, challenging, and promising characteristics suitable for various biomedical applications. Among modern biomedical potential of AgNPs, tremendous interest is oriented toward the therapeutically enhanced personalized healthcare practice. AgNPs proved to have genuine features and impressive potential for the development of novel antimicrobial agents, drug-delivery formulations, detection and diagnosis platforms, biomaterial and medical device coatings, tissue restoration and regeneration materials, complex healthcare condition strategies, and performance-enhanced therapeutic alternatives. Given the impressive biomedical-related potential applications of AgNPs, impressive efforts were undertaken on understanding the intricate mechanisms of their biological interactions and possible toxic effects. Within this review, we focused on the latest data regarding the biomedical use of AgNP-based nanostructures, including aspects related to their potential toxicity, unique physiochemical properties, and biofunctional behaviors, discussing herein the intrinsic anti-inflammatory, antibacterial, antiviral, and antifungal activities of silver-based nanostructures.

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Biomedical Applications of Silver Nanoparticles: An Up-to-Date Overview

Popularity of graphene oxide (GO) became ballistic in the last few years – in short, it almost seems that now everyone wants to work with graphene. However, as the number of electrochemical papers about graphene grows, so is the amount of misinterpretations. Our work was mostly focused on preparation of GO and its electrochemical properties, namely catalysis. Our results show, that chemical preparation of GO by strong oxidation is very tricky. Several approaches were tested, such as different sizes of graphite particles, oxidation mixtures, even repetitive preparations under the same conditions usually resulted in different products. Another big topic are impurities which are present due to natural occurrence in graphite and some of them might be also introduced during purification processes of GO. This could also lead to often observed catalytic activity of graphene. From our observations neither selectivity nor significant electrocatalytic abilities of the reduced graphene oxide modified electrodes towards H2O2 were observed. Moreover, our results suggest that GO does not need linking molecules in order to be deposited onto the surface of the electrodes, since it attaches spontaneously and keeps its electrochemical properties. Graphene is usually reported as a superior material, but its proper description and characterization should not be underestimated.

About graphene oxide

Z. Jiang, 2, ∗ Y. Zhang, H. L. Stormer, 3, 4 and P. Kim Department of Physics, Columbia University, New York, New York 10027, USA National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA Bell Laboratories, Alcatel-Lucent, Murray Hill, New Jersey 07974, USA (Dated: February 1, 2008)

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The Nature of Quantum Hall States near the Charge Neutral Dirac Point in Graphene

Zirconia surface modifications for implant dentistry

Bacterial infections represent nowadays the major reason of biomaterials implant failure, however, most of the available implantable materials do not hold antimicrobial properties, thus requiring antibiotic therapy once the infection occurs. The fast raising of antibiotic-resistant pathogens is making this approach as not more effective, leading to the only solution of device removal and causing devastating consequences for patients. Accordingly, there is a large research about alternative strategies based on the employment of materials holding intrinsic antibacterial properties in order to prevent infections. Between these new strategies, new technologies involving the use of carbon-based materials such as carbon nanotubes, fullerene, graphene and diamond-like carbon shown very promising results. In particular, graphene- and graphene-derived materials (GMs) demonstrated a broad range antibacterial activity toward bacteria, fungi and viruses. These antibacterial activities are attributed mainly to the direct physicochemical interaction between GMs and bacteria that cause a deadly deterioration of cellular components, principally proteins, lipids, and nucleic acids. In fact, GMs hold a high affinity to the membrane proteoglycans where they accumulate leading to membrane damages; similarly, after internalization they can interact with bacteria RNA/DNA hydrogen groups interrupting the replicative stage. Moreover, GMs can indirectly determine bacterial death by activating the inflammatory cascade due to active species generation after entering in the physiological environment. On the opposite, despite these bacteria-targeted activities, GMs have been successfully employed as pro-regenerative materials to favor tissue healing for different tissue engineering purposes. Taken into account these GMs biological properties, this review aims at explaining the antibacterial mechanisms underlying graphene as a promising material applicable in biomedical devices.

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Antimicrobial Mechanisms and Effectiveness of Graphene and Graphene-Functionalized Biomaterials. A Scope Review.

Graphene- and graphene oxide-based nanomaterials have gained broad interests in research because of their unique physiochemical properties. The 2D allotropic structure allows it to be used in various biological fields. The biomedical applications of graphene and its composite include its use in gene and small molecular drug delivery. It is further used for biofunctionalization of protein, in anticancer therapy, as an antimicrobial agent for bone and teeth implantation. The biocompatibility of the newly synthesized nanomaterials allows its substantial use in medicine and biology. The current review summarizes the chemical structure and biological application of graphene in various fields.

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Graphene and graphene oxide as nanomaterials for medicine and biology application

Nanotechnology is widely used in our day to day life including its use in medicine. Using nanotechnology, it is easy to analyze and manipulate atoms, chemical bonds and molecules present between various compounds. Nanotechnology is used in the dental field as nano dentistry. While choosing the nanoparticle for the use in the field of nano dentistry its chemical, physical, along with the biological aspect of nanostructures are taken into account. Often various atoms or molecules are added to form the functional structure. Nanostructures are used in innovations or diagnosis of dentistry. Some nanoparticles are used for oral disease preventive drugs, prostheses and for teeth implantation. Nanomaterials further deliver oral fluid or drugs, preventing and curing some oral disease (oral cancer) and maintain oral health care up to a high extent. This review summarises the use of various widely used nanoparticle in the field of dentistry.

Nanoparticles used in dentistry: A review

The current study checks the effect of various concentrations of dietary graphene oxide (GO) nano-sheets on the development of Drosophila melanogaster. GO was synthesized and characterized by XRD, FTIR, FESEM, and TEM analytical techniques. Various concentrations of GO were mixed with the fly food and flies were transferred to the vial. Various behavioral and morphological as well as genetic defects were checked on the different developmental stages of the offspring. In the larval stage of development, the crawling speed and trailing path change significantly than the control. GO induces the generation of oxygen radicals within the larval hemolymph as evidenced by nitroblue tetrazolium assay. GO induces DNA damage within the gut cell, which was detected by Hoechst staining and within hemolymph by comet assay. Adult flies hatched after GO treatment show defective phototaxis and geotaxis behavior. Besides behavior, phenotypic defects were observed in the wing, eye, thorax bristles, and mouth parts. At 300 mg/L concentration, wing spots were observed. Altogether, the current study finds oral administration of GO which acts as a mutagen and causes various behavioral and developmental defects in the offspring. Here for the first time, we are reporting GO, which acts as a teratogen in Drosophila, besides its extensive medical applications.

Oral administration of graphene oxide nano-sheets induces oxidative stress, genotoxicity, and behavioral teratogenicity in Drosophila melanogaster

Antimicrobial activity of nanoparticle-based dental fillers on novel chromogenic bacteria Enterobacter ludwigii

The effects of teeth-blackening bacteria Enterobacter ludwigii on the physiological system were investigated using the model organism Drosophila melanogaster. The bacteria were mixed with the fly food, and its effect was checked on the growth, development and behaviour of Drosophila. Microbes generate reactive oxygen species (ROS) within the haemolymph of the larvae once it enters into the body. The increased amount of ROS was evidenced by the NBT assay and using 2',7'-dichlorofluorescin diacetate dye, which indicates the mitochondrial ROS. The increased amount of ROS resulted in a number of abnormal nuclei within the gut. Besides that larvae walking became sluggish in comparison with wild type although the larvae crawling path did not change much. Flies hatched from the infectious larvae have the posterior scutellar bristle absent from the thorax and abnormal mechanosensory hairs in the eye, and they undergo time-dependent neurodegeneration as evidenced by the geotrophic and phototrophic assays. To decipher the mechanism of neurodegeneration, flies were checked for the presence of four important bioamines: tyramine, cadaverine, putrescine and histamine. Out of these four, histamine was found to be absent in infected flies. Histamine is a key molecule required for the functioning of the photoreceptor as well as mechanoreceptors. The mechanism via which mouth infectious bacteria E. ludwigii can affect the development and cause age-dependent neurodegeneration is explained in this paper.

Subhashree Priyadarsini

Papers

Graphene and graphene oxide as nanomaterials for medicine and biology application

Nanoparticles used in dentistry: A review

Oral administration of graphene oxide nano-sheets induces oxidative stress, genotoxicity, and behavioral teratogenicity in Drosophila melanogaster

Antimicrobial activity of nanoparticle-based dental fillers on novel chromogenic bacteria Enterobacter ludwigii

An infection of Enterobacter ludwigii affects development and causes age-dependent neurodegeneration in Drosophila melanogaster