Document Type

Theses, Ph.D

Disciplines

3.3 HEALTH SCIENCES

Abstract

Glioblastoma (GBM) is an aggressive, infiltrative astrocytic tumour in which pharmacotherapy remains constrained by the blood-brain barrier (BBB) and the heterogeneously altered blood brain tumour barrier, with additional limitations imposed by active efflux and the complexity of the tumour microenvironment. In this setting, externally addressable strategies that modulate transport and uptake at the site of disease are required. A stimuli-responsive chemotherapy platform was developed in which Lipo-DOXO was combined with two non-invasive physical modalities, low-frequency ultrasound (US) and cold atmospheric plasma (CAP), to enhance intratumoural delivery while limiting off-target effects. Liposomes were produced by thin-film hydration followed by a controlled, sequential extrusion process designed to achieve nanoscale dimensions while maintaining colloidal stability; purification and loading were validated by an ultracentrifugation/absorbance workflow to ensure reproducible composition and performance. Functional evaluation assigned distinct roles to each component of the platform. The carrier alone was largely well tolerated across glioma models, while the doxorubicin-loaded formulation expressed the intended antitumour profile, indicating that therapeutic activity was governed by payload release rather than vehicle toxicity. US acted primarily as a permeability adjunct, increasing particle-cell engagement, uptake, and local release within the operating window used; temperature-controlled experiments designed to suppress active cellular processes supported a predominantly mechanical contribution with limited direct injury. CAP functioned as a programmable stress-sensitiser and membrane modulator. Direct exposure produced stronger effects than plasma-activated medium, and physiological antioxidant buffering attenuated responses, implicating reactive oxygen- and nitrogen-species-mediated pathways and suggesting reorganisation of membrane order and trafficking routes that favour intracellular access and release. When combined, order proved critical. Application of CAP prior to US ii | P a g e consistently yielded the most favourable enhancement, consistent with redox-driven priming of cellular and vesicular interfaces followed by acoustic forces that promote contact, endocytosis, and on-site release. Reversing the sequence retained benefit relative to single-modality exposure but did not achieve the same depth of effect, indicating that acoustic stimulation without prior priming does not recruit equivalent uptake pathways. Scheduling was also consequential. Repeated CAP exposures produced cumulative gains that subsequently plateaued, aligning with activation of stress-response programmes and attrition of immediately susceptible subpopulations; a dosing regimen that retained residual drug and mediators outperformed full medium replacement, indicating that local priming can be preserved and compounded across treatment cycles. Critically, the combined approach translated from planar monolayers to three dimensional spheroids, where growth suppression and increased intracellular drug were preserved even under antioxidant buffering, reducing the likelihood of two-dimensional artefact and strengthening the rationale for in-vivo progression. Taken together, an externally addressable, energy-augmented nanochemotherapy is defined: cationic Liposomes engineered for stability and uptake; US deployed as a low-injury driver of permeability and distribution; CAP leveraged as a redox-membrane primer; and CAP→US identified as the preferred choreography. The platform converts delivery from a fixed constraint into a tuneable design variable suited to the spatial heterogeneity of GBM and to device-integrated translational studies.

DOI

https://doi.org/10.21427/a0ye-rw32

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