The most common treatment used for cancer is chemotherapy. Chemotherapeutic agents have a greater affinity for rapidly dividing cells which is a characteristic of tumour cells. Although anti-cancer agents have their advantages in providing anti-cancer effects, they can be seen as highly toxic molecules posing a threat to normal healthy tissue within the human body. However, these toxic therapies need to be delivered to tumour sites without damaging healthy tissue. Liposomes can serve as a delivery system for these toxic molecules and be delivered to the tumour site via the EPR effect. Hence, liposomes that fuse with tumour cell line membranes are advantageous in delivering payloads of drugs directly into the tumour cell without damaging normal healthy tissue. The aim of the study was to formulate an optimised liposome preparation in order to enhance cellular uptake by MCF-7, Caco-2 and C3A cancer cell lines via membrane fusion. The optimal liposome formulation was aimed to be prepared utilising a statistical design approach in order to determine the ranges of the parameters that were furthermost optimal in formulating an ideal liposome preparation. The primary screening design was conducted using a 24-1 fractional factorial design that took into account the four parameters that were used to determine the optimisation of the liposomal preparation. The four variables used in the liposome preparation were the phospholipid type (PS or DOPE), the concentration of cholesteryl hemisuccinate (CHEMS) (10 – 40 %), the concentration of PEG2000-PE (0.5 – 4 %) and liposome size (100 or 200 nm). Liposomes were prepared using thin film hydration method and characterisation for size and zeta potential was carried out using photon correlation spectroscopy (PCS). Visual characterisation of liposome size was carried out using atomic force microscopy (AFM). Liposomes were exposed the cancer cell lines with visualisation and uptake being measured using fluorescent microscopy and flow cytometry, respectively. An optimal liposome preparation was prepared following the statistical design method. The optimal liposome preparation consisted of phospholipid type PS, 22.91 % of CHEMS, 4 % of PEG2000-PE and a liposome size of 200 nm. AFM analysis has shown that optimal liposome sizes ranged between 130 and 170 nm. Flow cytometry analysis indicated high level of liposome uptake with actual values falling below the predicted values set out by the statistical design. Fluorescence microscopy captured images of the fluorescent liposomes concentrated on the membrane of cells. The objective of the study was to determine from literature which variables would be desirable in preparing an optimal non-targeted liposome preparation. This was achieved by identifying four such variables and utilising them in a statistical design approach which was screened in order to determine the ideal parameters in preparing the optimised liposome batch. Therefore, from the results obtained it can be concluded that the aim of the study were met by preparing an optimal liposome preparation that has the ability to fuse with the tumour cell line membranes.

Side effects of current chemotherapeutics limit their use in cancer therapy. Although many current drugs are highly toxic and potent, the effects they have on non-cancerous tissue are unbearable for patients. Targeting these drugs may provide a means to restrict their toxic effects to only cancer tissue while leaving healthy tissue unaffected. This approach requires that the drug is only available in cancer tissue, which has been achieved here by encapsulating drugs into liposomal nano-capsules which are capable of passively accumulating in cancerous tissue via the enhanced permeability and retention effect (EPR). In addition to localisation, a threshold dose must be achieved to deliver the desired toxic effect to the target tumour tissue. Previous strategies have relied on passive 'leaching' of the drug from liposomes, however this 'leaching' does not necessarily achieve the threshold dose required. In the present work, a new generation of liposomes has been developed whereby release is solely achieved in the presence of ultrasound triggered cavitation. Instigation of such cavitation events would normally require the target tissue be exposed to high and possibly damaging ultrasound pressures. To remove the need for these high pressures, cavitation nuclei have been developed to lower the cavitation threshold of surrounding media. To allow for improved co-localisation and treatment deeper into cancer tissue, cavitation nuclei were developed to be in the nanoscale size range. Two types of novel cavitation nuclei were produced, a rough surfaced carbon nanoparticle (CNP, ~180 nm) and smooth shaped polymeric nano-cup particle (NC, ~150, 470, or 770 nm). Both types of particle are solid nanoparticles with gas entrapped on their surface which was capable of cavitating in response to ultrasound without greatly affecting the particle itself. These particles are classified as cavicatalytic nanoparticles due to their ability to reduce the cavitation threshold of their surrounding media without being destroyed themselves. Finally, an entirely nanoscale release system was developed and tested in vitro and in vivo. The drug carrier (the liposome) and effector agent (the cavicatalytic nanoparticle) were used to demonstrate ultrasound triggered drug release, specifically in response to the generation of cavitation events. These cavitation events could be non-invasively monitored and characterised, adding to the potential clinical utility of the technologies developed and described here.