From micro to nano: downsizing self-assembling supramolecular hybrid gel beads from the micrometre to the nanometre scale for possible biomedical applications

The purpose of the study reported within this thesis was to fabricate multicomponent gel beads consisting of the polymer gel calcium alginate and the
supramolecular gel DBS-CONHNH2. This study built upon previous work in the Smith group wherein beads on the micrometre scale had been fabricated. Here, nano-scale beads are fabricated and reported. In order to achieve this, multiple combinations of parameters were tested in the same general method in order to further understand how each parameter (temperature, oil phase, pH, volume, etc.) affects the size of the beads achieved. Under certain parameters, beads below the upper injectable limit of 200 nm were produced, a significant step which opens up the possibility for biomedical applications of these beads. The beads were analysed via dynamic light scattering (DLS) and electron microscopy in order to attain measurements for size, whilst infrared spectroscopy (IR) and nuclear magnetic resonance (NMR) were used to ascertain composition and yield. Following the downsizing of these beads, magnetic iron oxide nanoparticles were introduced to the procedure with the aim of fabricating beads which will exhibit attraction to an applied magnetic field. By introducing this property, it is hoped that directed drug delivery may be possible in the future, with beads being administered intravenously and subsequently being directed to a target site under the influence of an applied magnetic field. Additional work was also conducted to investigate the effect of metal salts – specifically ferric and cupric chloride – on DBS-CONHNH2. The formation of nanoparticles was observed under electron microscopy, with some iron oxide species being formed in the case of ferric chloride.