Significance: Our bodies rely on molecular transport within a complex, nonequilibrium environment incorporating gradients of charged and neutral solutes. Concentration gradients near solid surfaces are known to induce material transport via diffusioosmotic fluid flow. These are well understood for charged molecules, but less so for neutral molecules such as glucose. Glucose is an important biological energy source and is often distributed in gradients across cell membranes, vasculature, tissues, and whole organs. We measure diffusioosmotic flow due to glucose gradients and find its speed depends only weakly on concentration. Our models can reproduce this behavior by accounting for strong interactions, concentration-dependent viscosity, and heterogeneous surfaces. Understanding these flows will allow us to harness them for improved transport of targeted nanomedicines.
From viruses to nanoparticles, constructs functionalized with multiple ligands display peculiar binding properties that only arise from multivalent effects. Using statistical mechanical modelling, we describe here how multivalency can be exploited to achieve what we dub range selectivity, that is, binding only to targets bearing a number of receptors within a specified range. We use our model to characterise the region in parameter space where one can expect range selective targeting to occur, and provide experimental support for this phenomenon. Overall, range selectivity represents a potential path to increase the targeting selectivity of multivalent constructs.
In the last years, there is a growing interest in the application of nanoscaled materials in cancer therapy because of their unique physico-chemical properties. However, the dark side of their usability is limited by their possible toxic behaviour and accumulation in living organisms. Starting from this assumption, the search for a green alternative to produce nanoparticles (NPs) or the discovery of green molecules, is a challenge in order to obtain safe materials. In particular, gold (Au NPs) and silver (Ag NPs) NPs are particularly suitable because of their unique physico-chemical properties, in particular plasmonic behaviour that makes them useful as active anticancer agents. These NPs can be obtained by green approaches, alternative to conventional chemical methods, owing to the use of phytochemicals, carbohydrates, and other biomolecules present in plants, fungi, and bacteria, reducing toxic effects. In addition, we analysed the use of green and stimuli-responsive polymeric bio-inspired nanovesicles, mainly used in drug delivery applications that have revolutionised the way of drugs supply. Finally, we reported the last examples on the use of metallic and Au NPs as self-propelling systems as new concept of nanorobot, which are able to respond and move towards specific physical or chemical stimuli in biological entities.
This study focuses on the contamination of 15 polycyclic aromatic hydrocarbons (PAHs), recommended by the US Environmental Protection Agency, in 10 tea brands distributed in Italy. Analyses were carried out with a procedure based on saponification, liquid-liquid extraction, and PAHs determination by high performance liquid chromatography with fluorescence detector. A comparison with ultrasonic extraction in bath water was also reported. Contamination is expressed as the sum of analyzed PAHs and ranged between 347 and 4120 ng/L with a mean value of 1675 ng/L. PAHs with 3-4 rings were dominant with a contribution of 92%, while 7% and 1% were found for PAHs with 5 and 6 rings, respectively. Moreover, data revealed that three samples exceeded the EU 2008 criteria established for drinking water in which the sum of benzo[k]fluoranthene, benzo[b]fluoranthene, benzo[g,h,i]perylene, and indeno[1,2,3-cd]pyrene is considered (<100 ng/L) and two samples exceeded the 10 ng/L level allowed for benzo[a]pyrene.
3 January 2018 in Journal of Chemical Technology & Biotechnology