Recent years have witnessed many breakthroughs in research on graphene (the first two-dimensional atomic crystal) as well as a significant advance in the mass production of this material. This one-atom-thick fabric of carbon uniquely combines extreme mechanical strength, exceptionally high electronic and thermal conductivities, impermeability to gases, as well as many other supreme properties, all of which make it highly attractive for numerous applications. Here we review recent progress in graphene research and in the development of production methods, and critically analyse the feasibility of various graphene applications.

BackgroundChronic conditions are an increasing challenge for individuals and the health care system. Smartphones and health apps are potentially promising tools to change health-related behaviors and manage chronic conditions.ObjectiveThe aim of this study was to explore (1) the extent of smartphone and health app use, (2) sociodemographic, medical, and behavioral correlates of smartphone and health app use, and (3) associations of the use of apps and app characteristics with actual health behaviors.MethodsA population-based survey (N=4144) among Germans, aged 35 years and older, was conducted. Sociodemographics, presence of chronic conditions, health behaviors, quality of life, and health literacy, as well as the use of the Internet, smartphone, and health apps were assessed by questionnaire at home visit. Binary logistic regression models were applied.ResultsIt was found that 61.25% (2538/4144) of participants used a smartphone. Compared with nonusers, smartphone users were younger, did more research on the Internet, were more likely to work full-time and more likely to have a university degree, engaged more in physical activity, and less in low fat diet, and had a higher health-related quality of life and health literacy. Among smartphone users, 20.53% (521/2538) used health apps. App users were younger, less likely to be native German speakers, did more research on the Internet, were more likely to report chronic conditions, engaged more in physical activity, and low fat diet, and were more health literate compared with nonusers who had a smartphone. Health apps focused on smoking cessation (232/521, 44.5%), healthy diet (201/521, 38.6%), and weight loss (121/521, 23.2%). The most common app characteristics were planning (264/521, 50.7%), reminding (188/521, 36.1%), prompting motivation (179/521 34.4%), and the provision of information (175/521, 33.6%). Significant associations were found between planning and the health behavior physical activity, between feedback or monitoring and physical activity, and between feedback or monitoring and adherence to doctor’s advice.ConclusionsAlthough there were many smartphone and health app users, a substantial proportion of the population was not engaged. Findings suggest age-related, socioeconomic-related, literacy-related, and health-related disparities in the use of mobile technologies. Health app use may reflect a user’s motivation to change or maintain health behaviors. App developers and researchers should take account of the needs of older people, people with low health literacy, and chronic conditions.

Nanoparticles assembled from poly(D,L-lactic acid)-poly(ethylene glycol) (PLA-PEG) block copolymers may have a therapeutic application in site-specific drug delivery. A series of AB block copolymers based on a fixed PEG block (5 kDa) and a varying PLA segment (2-110 kDa) have been synthesized by the ring-opening polymerization of D,L-lactide using stannous octoate as a catalyst. These copolymers assembled to form spherical nanoparticles in aqueous media following precipitation from a water-miscible organic solvent. 1 H NMR studies of the PLA-PEG nanoparticles in D2O confirmed their core-shell structure, with negligible penetration of the hydrated PEG chains into the PLA core. The influence of the PLA block molecular weight on the hydrodynamic size and micellar aggregation number of the assemblies was determined by dynamic and static light scattering techniques. The hydrodynamic radius of the PLA-PEG 2:5-30:5 nanoparticles was solely dependent on the copolymer architecture and scaled linearly as NPLA 1/3 , where NPLA is the number of monomeric units in the PLA block. The PEG chains of the small PLA-PEG 2:5 and 3:5 assemblies appeared to be fairly splayed as a consequence of their relatively low aggregation number and high surface coverage. However, as NPLA was increased to 6 kDa the area available per PEG chain at the periphery of the shell decreased significantly and then remained fairly constant with further increases in the molecular weight of the PLA block. The aggregation number and hence particle size of nanoparticles produced from copolymers with a PLA block of 45 kDa or more was found to also depend on the concentration of copolymer dissolved in the organic phase during preparation. This suggested that that the PEG chains had little influence on the assembly of the higher molecular weight copolymers.

Three-dimensional cell culture has many advantages over monolayer cultures, and spheroids have been hailed as the best current representation of small avascular tumours in vitro. However their adoption in regular screening programs has been hindered by uneven culture growth, poor reproducibility and lack of high-throughput analysis methods for 3D. The objective of this study was to develop a method for a quick and reliable anticancer drug screen in 3D for tumour and human foetal brain tissue in order to investigate drug effectiveness and selective cytotoxic effects. Commercially available ultra-low attachment 96-well round-bottom plates were employed to culture spheroids in a rapid, reproducible manner amenable to automation. A set of three mechanistically different methods for spheroid health assessment (Spheroid volume, metabolic activity and acid phosphatase enzyme activity) were validated against cell numbers in healthy and drug-treated spheroids. An automated open-source ImageJ macro was developed to enable high-throughput volume measurements. Although spheroid volume determination was superior to the other assays, multiplexing it with resazurin reduction and phosphatase activity produced a richer picture of spheroid condition. The ability to distinguish between effects on malignant and the proliferating component of normal brain was tested using etoposide on UW228-3 medulloblastoma cell line and human neural stem cells. At levels below 10 µM etoposide exhibited higher toxicity towards proliferating stem cells, whereas at concentrations above 10 µM the tumour spheroids were affected to a greater extent. The high-throughput assay procedures use ready-made plates, open-source software and are compatible with standard plate readers, therefore offering high predictive power with substantial savings in time and money.

As 95% of all prescriptions are for orally administered drugs, the issue of oral absorption is central to the development of pharmaceuticals. Oral absorption is limited by a high molecular weight (>500 Da), a high log P value (>2.0) and low gastrointestinal permeability. We have designed a triple action nanomedicine from a chitosan amphiphile: quaternary ammonium palmitoyl glycol chitosan (GCPQ), which significantly enhances the oral absorption of hydrophobic drugs (e.g., griseofulvin and cyclosporin A) and, to a lesser extent, the absorption of hydrophilic drugs (e.g., ranitidine). The griseofulvin and cyclosporin A C(max) was increased 6- and 5-fold respectively with this new nanomedicine. Hydrophobic drug absorption is facilitated by the nanomedicine: (a) increasing the dissolution rate of hydrophobic molecules, (b) adhering to and penetrating the mucus layer and thus enabling intimate contact between the drug and the gastrointestinal epithelium absorptive cells, and (c) enhancing the transcellular transport of hydrophobic compounds. Although the C(max) of ranitidine was enhanced by 80% with the nanomedicine, there was no appreciable opening of tight junctions by the polymer particles.