| Summary: | 博士 === 國立交通大學 === 材料科學與工程學系所 === 101 === In the clinical treatment of cardiovascular disease (CVD), a complicate physiological symptom has been reported, where the vessel occluded itself again, as a result of exaggerated proliferation of vascular smooth muscle cells (VSMCs). Although the common therapeutic strategies such as percutaneous transluminal coronary angioplasty (PTCA), atherectomy, and stenting have been largely utilized, the increasing risk of late thrombosis causing acute coronary diseases resulting from these therapeutic strategies is need for a comprehensive safety consideration. For these reasons, many pharmaceutical companies and researchers put extensive effort to develop a new therapeutic strategy. Nanotechnology is an attractive and prospective technology to providing a research proposal for the development of CVD treatment. Therefore, this study is focused on integrating therapeutic platform, antiproliferative agent, and colloidal chitosan-based carrier to synergize a potential strategy for the treatment of CVD
The first part of this thesis (Chapter 4) is employed a core-shell nanoparticle with a structural arrangement of magnolol-polyvinylpyrrolidone (PVP) core and chitosan shell. The shell was virtually constructed using a new type of amphiphilic chitosan-based hydrogel, i.e., carboxymethyl-hexanoyl chitosan (CHC). The highly biocompatible amphiphilic chitosan, which was previously developed in this lab, was employed as a drug carrier. A magnolol-polyvinylpyrrolidone (PVP) core phase was prepared, followed encapsulating by an amphiphilic carboxymethyl-hexanoyl chitosan (CHC) shell to form a magnolol-loaded core-shell hydrogel nanoparticles (termed Magnolol-CHC nanoparticles). The resulting Magnolol-CHC nanoparticles were employed for evaluation of drug release and controlled cytotoxic inhibition of VSMCs migration in vitro. A sustained release of the magnolol from the nanoparticles was determined. The Magnolol-CHC nanoparticles exhibited outstanding cellular uptake efficiency and under a cytotoxic evaluation, an increased anti-proliferative effect and effective inhibition of VSMC migration as a result of efficient intracellular delivery of the encapsulated magnolol in comparison to free magnolol was achieved. We then envision a potential intracellular medication strategy with improved biological and therapeutic efficacy using the Magnolol-CHC nanoparticles illustrated in this work.
Curcuminoids are recognized for their broad spectrum of biological activities and safety in foods and pharmaceuticals. Although previous reports suggested that curcuminoids are a class of effective antiproliferative, antimigratory, antioxidant, and anti-inflammatory agent; however, poor bioavailability has hampered the desired therapeutic use of curcuminoids in a number of clinical trials. To overcome those hurdles, a dual-ligand modification rendered the resulting modified chitosan (CHC) to be highly dissoluble in aqueous solution of neutral pH, biocompatible, and is capable of self-assembling to form well-defined nanocapsules upon encapsulating many water-insoluble substances in aqueous solutions.
In the second parts (Chapter 5), a highly potential drug, demethoxycurcumin which is one of the most potent derivatives of the curcuminoids, was employed.Unfortunately, there has no relevant reports on investigating demethoxycurcumin as an antirestenotic agent in vitro. Combining these reasons, a potential formulation via a low-dose sustained elution of demethoxycurcumin (DMC), through a self-assembled amphiphilic carbomethyl-hexanol chitosan (CHC) nanomatrix was constructed. Manipulating the cellular internalization and controlled cytotoxic effect of DMC-CHC nanoparticles over the VSMCs was elucidated. The DMC-CHC nanoparticles, which were systematically characterized in terms of structural morphology, surface potential, encapsulation efficiency, and DMC nanocrystallite distribution, exhibited rapid cellular uptake efficiency and considerably improved cytotoxic potency by 2.8 times compared to the free DMC. Under a cytotoxic evaluation, an improved antiproliferative effect and effective inhibition of VSMCs migration as a result of highly-efficient intracellular delivery of the encapsulated DMC in comparison to free DMC was achieved, which also confirmed with a subsequent protein analysis. Cellular drug release and distribution of DMC after internalization into VSMCs was experimentally determined. This work may open a potential intracellular medicinal strategy with improved biological and therapeutic efficacy using the DMC-CHC nanoparticles illustrated in this work.
After this potential formulation being extensively explored, a facile nano-topographical control over a stainless steel surface via an electrophoretic deposition of colloidal amphiphilic chitosan for preferential growth, proliferation, or migration of vascular smooth muscle cells (VSMCs) and endothelial cells (HUVECs) was evaluated (Chapter 6). Atomic force microscopy (AFM) revealed that the colloidal surface illustrated a deposition time-dependent nano-topographical evolution, wherein two different nano-topographic textures indexed by “Kurtosis” (Rkur) value were easily designed, which hereinafter, termed as “sharp” (i.e., high peak-to-valley texture) surface, CHC-1 and “flat” (i.e., low peak-to-valley texture) surface, CHC-5. Cellular behavior of VSMCs and HUVECs, on both surfaces demonstrated topographically-dependent morphogenesis, adherent responses, and biochemical properties in comparison with bare stainless steel. This work highlighted a promising development of such a nano-topographic biofunctionalized surface upon which a cell-specific therapeutic strategy can be easily manipulated with improved therapeutic performance.
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