Herein, we report a novel and solvent-free technique for the encapsulation of pharmaceuticals that allows achieving controllable release rates. This method utilizes the deposition of a plasma polymer ...coating of controlled chemistry and thickness on the outer surface of drug particles placed under continuous agitation.
The wetting of a material can be tuned by changing the roughness on its surface. Recent advances in the field of nanotechnology open exciting opportunities to control macroscopic wetting behaviour. ...Yet, the benchmark theories used to describe the wettability of macroscopically rough surfaces fail to fully describe the wetting behaviour of systems with topographical features at the nanoscale. To shed light on the events occurring at the nanoscale we have utilised model gradient substrata where surface nanotopography was tailored in a controlled and robust manner. The intrinsic wettability of the coatings was varied from hydrophilic to hydrophobic. The measured water contact angle could not be described by the classical theories. We developed an empirical model that effectively captures the experimental data, and further enables us to predict the wetting of surfaces with nanoscale roughness by considering the physical and chemical properties of the material. The fundamental insights presented here are important for the rational design of advanced materials having tailored surface nanotopography with predictable wettability.
Surface modification has been identified as an important technique that could improve the response of the body to implanted medical devices. Collagen production by fibroblasts is known to play a ...vital role in wound healing and device fibrous encapsulation. However, how surface chemistry affects collagen I and III deposition by these cells has not been systematically studied. Here, we report how surface chemistry influences the deposition of collagen I and III by primary human dermal fibroblasts. Amine (NH3), carboxyl acid (COOH), and hydrocarbon (CH3) surfaces were generated by plasma deposition. This is a practically relevant tool to deposit a functional coating on any type of substrate material. We show that fibroblasts adhere better and proliferate faster on amine-rich surfaces. In addition, the initial collagen I and III production is greater on this type of coating. These data indicates that surface modification can be a promising route for modulating the rate and level of fibrous encapsulation and may be useful in informing the design of implantable biomedical devices to produce more predictable clinical outcomes.
Long-term speciation and lability of silver (Ag-), silver chloride (AgCl-), and silver sulfide nanoparticles (Ag2S-NPs) in soil were studied by X-ray absorption spectroscopy (XAS), and newly ...developed “nano” Diffusive Gradients in Thin Films (DGT) devices. These nano-DGT devices were designed specifically to avoid confounding effects when measuring element lability in the presence of nanoparticles. The aging profile and stabilities of the three nanoparticles and AgNO3 (ionic Ag) in soil were examined at three different soil pH values over a period of up to 7 months. Transformation of ionic Ag, Ag-NP and AgCl-NPs were dependent on pH. AgCl formation and persistence was observed under acidic conditions, whereas sulfur-bound forms of Ag dominated in neutral to alkaline soils. Ag2S-NPs were found to be very stable under all conditions tested and remained sulfur bound after 7 months of incubation. Ag lability was characteristically low in soils containing Ag2S-NPs. Other forms of Ag were linked to higher DGT-determined lability, and this varied as a function of aging and related speciation changes as determined by XAS. These results clearly indicate that Ag2S-NPs, which are the most environmentally relevant form of Ag that enter soils, are chemically stable and have profoundly low Ag lability over extended periods. This may minimize the long-term risks of Ag toxicity in the soil environment.
Poly(2-oxazoline)s are emerging revolutionary biomaterials, exhibiting comparable and even superior properties to well-established counterparts. Overcoming current tedious wet synthesis methods, we ...report solvent-free and substrate independent, plasma polymerised nanoscale biocompatible polyoxazoline coatings capable of controlling protein and cell adhesion, and significantly reducing biofilm build up.
Endoleak represents the most common complication after endovascular aortic aneurysm repair (EVAR) and is deï¬ ned as persistent perfusion of the aneurysmal sac, which subsequently could lead to its ...expansion and possibly rupture. There are different types of endoleaks, depending on their inï¬ ow source, regardless of the number and type of other vessels involved in the outï¬ ow (endoleak type I A/B/С, type II, type III, type IV and type V). The current gold standard for the diagnosis of endoleak is the contrast-enhanced helical computed tomography (CT). Since, there is no generally accepted consensus for the best surveillance and treatment methods for this pathology, in this article we will present the most effective endovascular interventions for the successful management of the different types of endoleaks.
We demonstrate that fluorescence of single molecules in the nanometric vicinity of a thin gold film can be effectively excited and detected through the film with an epi-illumination scanning confocal ...microscope. A full theoretical treatment of the fluorescence signal indicates that both excitation and emission are surface-plasmon mediated. Remarkably, the number of photons detectable from chromophores perpendicular to the interface is enhanced by the presence of the metal.
The catalytic activity of multi-walled carbon nanotubes (MWCNTs) in oxy-steam reforming of methanol (ASRM) was investigated for the first time. We demonstrate that CNTs are a potent catalytic ...material for hydrogen generation in oxy-steam reforming of methanol.
Wear particle analysis can be potentially developed as an effective method for assessment of osteoarthritis (OA). To achieve this goal, the surface morphological and mechanical properties of human ...wear particles extracted from the osteoarthritic synovial joints with different OA grades need to be studied. Atomic force microscopy (AFM) has been used for cartilage analysis owing to its high resolution and the capability of revealing both mechanical properties and surface topographical data in three-dimensions. Few studies have been conducted on human wear particles due to difficulties in obtaining the samples and technical challenges in preparing wear debris samples for AFM investigations in a hydrated environment. This work aimed to develop a suitable preparation technique to study the mechanical properties and surface morphology of human wear particles using AFM. Wear particles were separated from synovial fluid samples which were collected from OA patients and deposited on an aldehyde functional plasma polymer surface to immobilise wear particles. They were imaged for the first time using AFM. The nanoscaled surface topographies and nanomechanical properties of the particles were obtained in a hydrated mode. The methodology established in this study enables investigations of the surface morphology and mechanical properties of wear particles at the nanoscale for better understanding of OA and the possibility of developing a new diagnostic method based on the wear debris analysis technique.
In this study, the antibacterial efficacy of NO-releasing porous silicon nanoparticles (pSiNPs) is reported. NO-releasing pSiNPs were produced via the conjugation of S-nitrosothiol (SNO) and ...S-nitrosoglutathione (GSNO) donors to the nanoparticle surfaces. The release of the conjugated NO caused by the decomposition of the conjugated SNO and GSNO was boosted in the presence of ascorbic acid. The released NO was bactericidal to Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli), and eliminated bacterial growth within 2 h of incubation without compromising the viability of mammalian cells. These results demonstrate the advantages of NO-releasing pSiNPs for antibacterial applications, for example, in chronic wound treatment.
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