Antimicrobial Effects of Biogenic Nanoparticles

Infectious diseases pose one of the greatest health challenges in the medical world. Though numerous antimicrobial drugs are commercially available, they often lack effectiveness against recently developed multidrug resistant (MDR) microorganisms. This results in high antibiotic dose administration and a need to develop new antibiotics, which in turn requires time, money, and labor investments. Recently, biogenic metallic nanoparticles have proven their effectiveness against MDR microorganisms, individually and in synergy with the current/conventional antibiotics. Importantly, biogenic nanoparticles are easy to produce, facile, biocompatible, and environmentally friendly in nature. In addition, biogenic nanoparticles are surrounded by capping layers, which provide them with biocompatibility and long-term stability. Moreover, these capping layers provide an active surface for interaction with biological components, facilitated by free active surface functional groups. These groups are available for modification, such as conjugation with antimicrobial drugs, genes, and peptides, in order to enhance their efficacy and delivery. This review summarizes the conventional antibiotic treatments and highlights the benefits of using nanoparticles in combating infectious diseases

Gold Nanoparticles in Diagnostics and Therapeutics for Human Cancer

The application of nanotechnology for the treatment of cancer is mostly based on early tumor detection and diagnosis by nanodevices capable of selective targeting and delivery of chemotherapeutic drugs to the specific tumor site. Due to the remarkable properties of gold nanoparticles, they have long been considered as a potential tool for diagnosis of various cancers and for drug delivery applications. These properties include high surface area to volume ratio, surface plasmon resonance, surface chemistry and multi-functionalization, facile synthesis, and stable nature. Moreover, the non-toxic and non-immunogenic nature of gold nanoparticles and the high permeability and retention effect provide additional benefits by enabling easy penetration and accumulation of drugs at the tumor sites. Various innovative approaches with gold nanoparticles are under development. In this review, we provide an overview of recent progress made in the application of gold nanoparticles in the treatment of cancer by tumor detection, drug delivery, imaging, photothermal and photodynamic therapy and their current limitations in terms of bioavailability and the fate of the nanoparticles

Low Concentrations of Vitamin C Reduce the Synthesis of Extracellular Polymers and Destabilize Bacterial Biofilms

Extracellular polymeric substances (EPS) produced by bacteria form a matrix supporting the complex three-dimensional architecture of biofilms. This EPS matrix is primarily composed of polysaccharides, proteins and extracellular DNA. In addition to supporting the community structure, the EPS matrix protects bacterial biofilms from the environment. Specifically, it shields the bacterial cells inside the biofilm, by preventing antimicrobial agents from getting in contact with them, thereby reducing their killing effect. New strategies for disrupting the formation of the EPS matrix can therefore lead to a more efficient use of existing antimicrobials. Here we examined the mechanism of the known effect of vitamin C (sodium ascorbate) on enhancing the activity of various antibacterial agents. Our quantitative proteomics analysis shows that non-lethal concentrations of vitamin C inhibit bacterial quorum sensing and other regulatory mechanisms underpinning biofilm development. As a result, the EPS biosynthesis in reduced, and especially the polysaccharide component of the matrix is depleted. Once the EPS content is reduced beyond a critical point, bacterial cells get fully exposed to the medium. At this stage, the cells are more susceptible to killing, either by vitamin C-induced oxidative stress as reported here, or by other antimicrobials or treatments

Basement membrane components are key players in specialized extracellular matrices

More than three decades ago, basement membranes (BMs) were described as membrane-like structures capable of isolating a cell from and connecting a cell to its environment. Since this time, it has been revealed that BMs are specialized extracellular matrices (sECMs) with unique components that support important functions including differentiation, proliferation, migration, and chemotaxis of cells during development. The composition of these sECM is as unique as the tissues to which they are localized, opening the possibility that such matrices can fulfill distinct functions. Changes in BM composition play significant roles in facilitating the development of various diseases. Furthermore, tissues have to provide sECM for their stem cells during development and for their adult life. Here, we briefly review the latest research on these unique sECM and their components with a special emphasis on embryonic and adult stem cells and their niches

DNA tracking within a nanochannel: device fabrication and experiments

Fabrication of nanochannels is drawing considerable interest due to its broad applications in nanobiotechnology (e.g. biomolecular sensing and single DNA manipulation). Nanochannels offer distinct advantages in allowing a slower translocation and multiple sensing spots along the channel, both of which improve the read-out resolution. However, implementing electrodes inside the nanochannel has rarely been demonstrated to our knowledge. The device described in this work is a Si–Glass anodically bonded Lab-on-a-Chip (LOC) device of a few millimetres in size capable of performing DNA manipulation. The LOC device structure is based on two mainstream microchannels interconnected by nanochannels. DNA, once trapped within the nanochannel, has been tracked throughout the length of the channel and the data have been recorded and analysed.Peer Reviewe

DNA tracking within a nanochannel: device fabrication and experiments

Fabrication of nanochannels is drawing considerable interest due to its broad applications in nanobiotechnology (e.g. biomolecular sensing and single DNA manipulation). Nanochannels offer distinct advantages in allowing a slower translocation and multiple sensing spots along the channel, both of which improve the read-out resolution. However, implementing electrodes inside the nanochannel has rarely been demonstrated to our knowledge. The device described in this work is a Si–Glass anodically bonded Lab-on-a-Chip (LOC) device of a few millimetres in size capable of performing DNA manipulation. The LOC device structure is based on two mainstream microchannels interconnected by nanochannels. DNA, once trapped within the nanochannel, has been tracked throughout the length of the channel and the data have been recorded and analysed.Peer Reviewe

NaB integrated graphene oxide membranes for enhanced cell viability and stem cell properties of human adipose stem cells

Here we present the integration of boron (NaB) with graphene oxide (GO) to develop a new class of membranes which are biocompatible and cost-effective for cell and tissue culture studies. Ethanol (EtOH) assisted the uniform dispersion of GO flakes on top of a glass substrate. We investigated the effect of a GO + NaB membrane on the growth and proliferation of hASCs. hASCs showed better cell viability on NaB integrated GO membranes compared to their respective controls. The concentrations of NaB and GO are 0.02% and 1/20 of stock (0.024%) respectively. To our knowledge this is the first time that enhanced cell proliferation and attachment ability of hASCs with NaB integrated GO membranes has been observed. Our study provides a platform for the development of 3D-GO scaffold systems combined with NaB in tissue engineering

The metabolic syndrome resulting from a knockout of the NEIL1 DNA glycosylase

Endogenously formed reactive oxygen species continuously damage cellular constituents including DNA. These challenges, coupled with exogenous exposure to agents that generate reactive oxygen species, are both associated with normal aging processes and linked to cardiovascular disease, cancer, cataract formation, and fatty liver disease. Although not all of these diseases have been definitively shown to originate from mutations in nuclear DNA or mitochondrial DNA, repair of oxidized, saturated, and ring-fragmented bases via the base excision repair pathway is known to be critical for maintaining genomic stability. One enzyme that initiates base excision repair of ring-fragmented purines and some saturated pyrimidines is NEIL1, a mammalian homolog to Escherichia coli endonuclease VIII. To investigate the organismal consequences of a deficiency in NEIL1, a knockout mouse model was created. In the absence of exogenous oxidative stress, neil1 knockout (neil1(−/−)) and heterozygotic (neil1(+/−)) mice develop severe obesity, dyslipidemia, and fatty liver disease and also have a tendency to develop hyperinsulinemia. In humans, this combination of clinical manifestations, including hypertension, is known as the metabolic syndrome and is estimated to affect >40 million people in the United States. Additionally, mitochondrial DNA from neil1(−/−) mice show increased levels of steady-state DNA damage and deletions relative to wild-type controls. These data suggest an important role for NEIL1 in the prevention of the diseases associated with the metabolic syndrome