Controlled degradation of polycaprolactone-based micropillar arrays.

Herein we demonstrate the fabrication of arrays of micropillars, achieved through the combination of direct laser writing and nanoimprint lithography. By combining two diacrylate monomers, polycaprolactone dimethacrylate (PCLDMA) and 1,6-hexanediol diacrylate (HDDA), two copolymer formulations that, owing to the varying ratios of the hydrolysable ester functionalities present in the polycaprolactone moiety, can be degraded in the presence of base in a controllable manner. As such, the degradation of the micropillars can be tuned over several days as a function of PCLDMA concentration within the copolymer formulations, and the topography greatly varied over a short space of time, as visualised using scanning electron microscopy and atomic force microscopy.

The UCD nanosafety workshop (03 December 2018): towards developing a consensus on safe handling of nanomaterials within the Irish university labs and beyond - a report.

Careful handling of the nanomaterials (NMs) in research labs is crucial to ensure a safe working environment. As the largest university in Ireland, University College Dublin (UCD) has invested significant resources to update researchers working with NMs. Due to sizes often <100 nm, the NMs including nanoparticles, harbor unprecedented materialistic properties, for example, enhanced reactivity, conductivity, fluorescence, etc.

Mechanisms of Polymer-Templated Nanoparticle Synthesis: Contrasting ZnS and Au.

We combine solution small-angle X-ray scattering (SAXS) and high-resolution analytical transmission electron microscopy (ATEM) to gain a full mechanistic understanding of substructure formation in nanoparticles templated by block copolymer reverse micelles, specifically poly(styrene)-block-poly(2-vinylpyridine). We report a novel substructure for micelle-templated ZnS nanoparticles, in which small crystallites (∼4 nm) exist within a larger (∼20 nm) amorphous organic-inorganic hybrid matrix. The formation of this complex structure is explained via SAXS measurements that characterize in situ for the first time the intermediate state of the metal-loaded micelle core: Zn(2+) ions are distributed throughout the micelle core, which solidifies as a unit on sulfidation.

Modular and Versatile Spatial Functionalization of Tissue Engineering Scaffolds through Fiber-Initiated Controlled Radical Polymerization.

Native tissues are typically heterogeneous and hierarchically organized, and generating scaffolds that can mimic these properties is critical for tissue engineering applications. By uniquely combining controlled radical polymerization (CRP), end-functionalization of polymers, and advanced electrospinning techniques, a modular and versatile approach is introduced to generate scaffolds with spatially organized functionality. Poly-ε-caprolactone is end functionalized with either a polymerization-initiating group or a cell-binding peptide motif cyclic Arg-Gly-Asp-Ser (cRGDS), and are each sequentially electrospun to produce zonally discrete bilayers within a continuous fiber scaffold.