This study compares the performance of a microfluidic technique and a conventional bulk method to manufacture conjugated polymer nanoparticles (CPNs) embedded within a biodegradable poly(ethylene glycol) methyl ether-blockpoly(lactide-co-glycolide) (PEG5K-PLGA55K) matrix. The influence of PEG5K-PLGA55K and conjugated polymers cyanosubstituted poly(p-phenylene vinylene) (CN-PPV) and poly(9,9-dioctylfluorene-2,1,3-benzothiadiazole) (F8BT) on the physicochemical properties of the CPNs was also evaluated. Both techniques enabled CPN production with high end product yields (~70-95%). However, while the bulk technique (solvent displacement) under optimal conditions generated small nanoparticles (~70-100 nm) with similar optical properties (quantum yields ~35%), the microfluidic approach produced larger CPNs (140-260 nm) with significantly superior quantum yields (49-55%) and tailored emission spectra. CPNs containing CN-PPV showed smaller size distributions and tuneable emission spectra compared to F8BT systems prepared under the same conditions. The presence of PEG5K-PLGA55K did not affect the size or optical properties of the CPNs and provided a neutral net electric charge as is often required for biomedical applications. The microfluidics flowbased device was successfully used for the continuous preparation of CPNs over a 24 hour period. On the basis of the results presented here, it can be concluded that the microfluidic device used in this study can be used to optimize the production of bright CPNs with tailored properties with good reproducibility.

Poly(vinyl alcohol) is a non-toxic, biosynthetic polymer and biocompatible polymer that has the ability to form hydrogels either via chemical or physical crosslinking. Whilst chemical crosslinking provides greater control on the properties of the resultant hydrogel, physically crosslinked hydrogels or blends with other biocompatible polymers are more suited for biomedical applications. In this paper we report a systematic study on the effect of varying concentrations of PVA, physical methods of crosslinking, and PVA-gelatin and PVA-PVP blends on the physical and mechanical properties of the hydrogels.

In this publication, we describe the synthesis of near-IR emitting conjugated polymer nanoparticles with an engineered surface, and their use in biological imaging.

Poly(2-hydroxyethyl methacrylate) pHEMA is a widely used hydrogel for several biomedical applications, however, cell adhesion and proliferation are limited in these polymers. In this study the strategy of phosphate containing monomer based copolymerisation has been used to molecularly engineer poly(2-hydroxyethyl methacrylate) hydrogels. Ethylene glycol methacrylate phosphate EGMP, a proton conducting electrolyte, was copolymerised with HEMA and incorporated at varying monomer feed ratios to enhance the swelling dynamics and improve the ability of pHEMA based hydrogel sponges to facilitate cell adhesion and mineralization and hence expand their biomedical application. The hydration of the copolymer gels showed that there was a direct correlation to the amount of EGMP incorporated within the polymeric network and the degree of hydration increased with increasing concentration of EGMP. EGMP in its polymeric form is a polyelectrolyte due to the readiness of the pendant phosphate group to ionise in low or high pH solution. Evaluation of the thermal behaviour showed that T g increased with increasing EGMP and although presence of water influenced transitions within these novel EGMP polymer networks, it did not have a deteriorating effect on the stiffness within the target temperature range even when fully hydrated. Furthermore, the damping or energy dissipation of the system increases in the ambient body temperature range, which is of particular interest for in vivo use.