RAFT Polymerization of N-[3-(Trimethoxysilyl)-propyl]acrylamide and Its Versatile Use in Silica Hybrid Materials.

Reversible addition-fragmentation chain transfer (RAFT) polymerization and characterization of an alkoxysilane acrylamide monomer using a trithiocarbonate chain transfer agent are described. Poly(N-[3-(trimethoxysilyl)propyl]acrylamide) (PTMSPAA) homopolymers are obtained with good control over the polymerization. A linear increase in the molecular weight is observed whereas the polydispersity values do not exceed 1.2 regardless of the monomer conversion. Moreover, PTMSPAA is used as a macro-RAFT agent to polymerize N-isopropylacrylamide (NIPAM). By varying the degree of polymerization of NIPAM within the block copolymer, different sizes of thermoresponsive particles are obtained. These particles are stabilized by the condensation of the alkoxysilane moieties of the polymers. Furthermore, a co-network of silica and PTMSPAA is prepared using the sol-gel process. After drying, transparent mesoporous hybrids are obtained with a surface area of up to 400 m(2) g(-1).

Collaboration for clinical innovation: a nursing and engineering alliance for better patient care.

BACKGROUND: There is significant need and enormous potential for innovation in clinical settings. However, for various reasons, this potential is rarely realised. AIMS: This paper aims to present a collaborative approach to innovation between clinicians and engineers, using two nursing case studies as examples. Suggestions are offered to improve facilitation of innovation in healthcare settings. METHODS: An engineering design process was applied to develop novel medical devices in response to unmet clinical needs identified by nurses. This process includes problem exploration, definition of project scope, concept generation, detailed design, manufacture, prototype evaluation and iterative design improvements. RESULTS: Two case studies are presented to showcase the results of this multidisciplinary approach to innovation. Both projects resulted in novel medical devices being put into clinical use safely and effectively. CONCLUSIONS: Collaboration between nurses and engineers facilitates rapid iteration of novel solutions to unmet clinical needs. Both professions have similar approaches to problem-solving, complemented by specialist knowledge in their contrasting areas of expertise, making for a highly capable multidisciplinary team.

Controlling particle size in the Stöber process and incorporation of calcium.

The StÓ§ber process is commonly used for synthesising spherical silica particles. This article reports the first comprehensive study of how the process variables can be used to obtain monodispersed particles of specific size. The modal particle size could be selected within in the range 20-500 nm. There is great therapeutic potential for bioactive glass nanoparticles, as they can be internalised within cells and perform sustained delivery of active ions. Biodegradable bioactive glass nanoparticles are also used in nanocomposites. Modification of the StÓ§ber process so that the particles can contain cations such as calcium, whilst maintaining monodispersity, is desirable. Here, whilst calcium incorporation is achieved, with a homogenous distribution, careful characterisation shows that much of the calcium is not incorporated. A maximum of 10 mol% CaO can be achieved and previous reports are likely to have overestimated the amount of calcium incorporated.

Theranostic mesoporous silica nanoparticles biodegrade after pro-survival drug delivery and ultrasound/magnetic resonance imaging of stem cells.

Increasing cell survival in stem cell therapy is an important challenge for the field of regenerative medicine. Here, we report theranostic mesoporous silica nanoparticles that can increase cell survival through both diagnostic and therapeutic approaches. First, the nanoparticle offers ultrasound and MRI signal to guide implantation into the peri-infarct zone and away from the most necrotic tissue. Second, the nanoparticle serves as a slow release reservoir of insulin-like growth factor (IGF)-a protein shown to increase cell survival. Mesenchymal stem cells labeled with these nanoparticles had detection limits near 9000 cells with no cytotoxicity at the 250 µg/mL concentration required for labeling. We also studied the degradation of the nanoparticles and showed that they clear from cells in approximately 3 weeks. The presence of IGF increased cell survival up to 40% (p<0.05) versus unlabeled cells under in vitro serum-free culture conditions.