Nano LIFE

In light of the challenges along with the traditional intravenous administration of chemotherapeutics, injectable hydrogel-drug system emerges as a powerful tool for noninvasive and in situ controlled-release of drugs. Herein, we report a novel strategy of drug delivery system with pH responsive injectable hydrogels by taking advantages of two biomaterials. The first one is a pH sensitive polymer-drug (prodrug) conjugate, poly (ethylene glycol)–doxorubicin (MPEG–DOX) with hydrazone linkage. This prodrug interacted with a second biomaterial, α-cyclodextrin (α-CD) under mild conditions and subsequently formed the hydrogels in minutes with tunable stiffness. The gels showed a sustained release behavior dependent on the surrounding pH and released drugs effectively killed tumor cells (MCF-7). The quick cell uptake and efficient intracellular delivery of DOX were observed under a confocal microscope. This study thus provides a novel and simple drug encapsulation strategy to deliver poorly soluble drugs in situ for a potential targeted chemotherapy.

Sindbis virus pathogenesis can be affected by mutations at residues 75 and 237, individually or in combination, of the E1 domain of the viral glycoprotein. To understand the changes in fusion properties driven by these mutations, we constructed three new fusogen molecules (FMs) derived from the Sindbis virus glycoprotein (G75D, S237A and G75DS237A), and investigated their fusion activity using lentiviral nanovectors. The co-expression of FMs and antibodies on the viral particles, were shown to mediate viral transduction on targeted cells. We found that the G75D mutation enhances the transduction efficiency by broadening the pH range required for fusion. Conversely, the S237A mutation impairs infectivity; however, adding the G75D site mutation to this molecule (G75DS237A) was able to partially restore infectivity. We further demonstrate that G75D can initiate virus fusion in both the early and the late endosomes, while S237A requires that the virus be functionally transported to the late endosomes for fusion to occur. This study sheds light on the mechanism by which mutations in FMs can affect viral fusion and transduction, and explores the use of our FM-bound lentiviral nanovector platform as tool to elucidate the mechanisms of viral membrane fusion.

There is an increasing interest in the use of silica nanoparticles (NPs) for bioapplications. Highly mesoporous fluorescein dye-doped silica NPs that can carry a drug payload have been successfully synthesized through a facile microemulsion process. The morphology of the as-prepared silica NPs were characterized by scanning electron microscope and transmission electron microscope, whereas their optical properties were studied by photoluminescence spectroscopy. The results revealed that these silica NPs exhibit excellent properties, including large pore volume, a narrow size distribution and strong fluorescent properties. The synthesized silica NPs showed a good biocompatibility and a low cytotoxicity when incubated in a murine fibroblast L-929 cell line. The obtained silica NPs were further used as drug delivery carriers to investigate the in vitro drug release properties using doxorubicin (DOX) as a representative drug model. It was shown that synthesized silica NPs well sustained drug release properties, suggesting their potential applications for drug delivery.

The flower-like Cu₂O nanostructures were hydrothermally synthesized without using any template or surfactant. The influences of hydrothermal temperature, reaction time and reactants concentrations on the growth of nanostructures were investigated in detail. The samples were characterized by scanning electron microscope (SEM) and X-ray powder diffraction (XRD). Cu₂O crystals with different shapes, i.e., flower-like (F-product) cubic box (CB-product) and cubic box with holes in each face (CBH-product), were synthesized by controlling the synthesis parameters and explored for CO catalytic oxidation. It was found that F-product showed higher catalytic than others.

One-step synthetic route has been developed for the preparation of Nd(OH)₃ nanorods in the presence of n-butylamine. The as-prepared sample is in hexagonal phase with good crystallinity, and made up of highly dispersed nanorods of 14–15 nm in diameter and up to 40–50 nm in length at 120°C for 24 h. Optical measurements show that these nanorods have intensive photoluminescence (PL) at room temperature and have the potential to become optical materials. Thermogravimetric analysis (TGA) of the Nd(OH)₃ nanorods reveals that the nanorods remain stable up to 220°C and decompose to the derived oxide of Nd₂O₃ at higher temperatures. The derived oxides show the promise active catalyst for the oxidation of carbon monoxide. In addition, this synthetic route has been developed for the synthesis of a series of other lanthanide hydroxides nanorods including Pr(OH)₃, Sm(OH)₃, Eu(OH)₃, Gd(OH)₃, Tb(OH)₃ and Dy(OH)₃, and their PL properties, thermostability and catalytic properties are investigated.

New techniques and materials are called for wastewater treatment due to the shortage of worldwide fresh water and the increasing water demand. As a simple and efficient method, adsorption technique has been extensively applied to remove organic and inorganic pollutants from contaminated water. The application of carbon nanomaterials, such as activated carbon, carbon nanotubes (CNTs), graphenes and their derivatives/analogues, in wastewater treatment has also been investigated due to their unique properties, such as wide availability, porous structure, large surface area, tunable morphology and nontoxicity. This review highlights the recent advances of wastewater treatment utilizing carbon nanomaterial modified composites as adsorbents. The adsorption phenomenon and its mechanism are briefly discussed. Detailed discussions are focused on the selective adsorption of carbon nanomaterial composites to unique pollutants. The remaining challenges are also mentioned.

In recent years, hundreds of genes have been linked to a variety of human diseases, and the field of gene therapy has emerged as a way to treat this wide range of diseases. The main goal of gene therapy is to find a gene delivery vehicle that can successfully target diseased cells and deliver therapeutic genes directly to their cellular compartment. The two main types of gene delivery vectors currently being investigated in clinical trials are recombinant viral vectors and synthetic nonviral vectors. Recombinant viral vectors take advantage of the evolutionarily optimized viral mechanisms to deliver genes, but they can be hard to specifically target in vivo and are also associated with serious side effects. Synthetic nonviral vectors are made out of highly biocompatible lipids or polymers, but they are much less efficient at delivering their genetic payload due to the lack of any active delivery mechanism. This mini review will introduce the current state of gene delivery in clinical trials, and discuss the specific challenges associated with each of these vectors. It will also highlight some specific gaps in knowledge that are limiting the advancement of this field and touch on the current areas of research being explored to overcome them.

Ag@C core–shell structures were prepared using hydrothermal methods by AgNO₃ reduction with ascorbic acid in the presence of polyacrylamide (PAM). Temperature plays a key role in the formation of the core–shell structures. The roles of reactants, surfactant concentrations and reaction time on the morphologies of core–shell nanoparticles were investigated in detail. This synthetic method is one-pot synthesis, which is fast, high-yield and environmental-friendly for fabrication of Ag@C core–shell structures. The surface properties of core–shell Ag@C nanoparticles were characterized by Raman spectroscopy.

Carbon nanotubes (CNT) have been known as one of the most important nanomaterials and their toxicological effects in vivo have been widely concerned. According to "Globally Harmonized System of classification and Labelling of Chemicals" (GHS) classification regulation, here, we analyzed the local toxicity (skin corrosion/irritation), acute oral toxicity, aquatic acute toxicity and reproductive toxicity of single-walled carbon nanotubes (SWCNTs) with the "Organization for Economic Co-operation and Development" (OECD) recommended chemical toxicity standard test methods. The experimental results showed that the LD₅₀ and LC₅₀ of SWCNT are all higher (LC₅₀ more than 5000 mg/kg bw, LC₅₀ more than 100 mg/L), but the skin irritation score is 0.6. As the standard of GHS, that means the SWCNT has no acute oral toxicity and aquatic acute toxicity, but it belongs to skin mild irritation substance. The investigations of reproductive toxicity showed that rate of cell micronuclei formation was significantly increased (p < 0.05) in 10.0 mg/kg dose group, and rate of mice sperm deformity was increased too (p < 0.05) in infected groups indicating that the SWCNT played a potentially role in reproductive toxicity.