Gold nanoparticles (GNPs) are widely used in diagnostics, drug delivery, biomedical imaging, photo-thermal therapy, and biomedical engineering due to their unique physical and chemical properties. In this study, we describe the application of GNPs thr...
Gold nanoparticles (GNPs) are widely used in diagnostics, drug delivery, biomedical imaging, photo-thermal therapy, and biomedical engineering due to their unique physical and chemical properties. In this study, we describe the application of GNPs through their unique properties in diagnostics, therapies, and bone tissue regeneration.
In Chapter 1, we describe whether the GNP-5ʹ surface-functionalized with PEG, biotin, paclitaxel (PTX) and rhodamine B linked beta-cyclodextrin (β-CD) can be useful as a theranostic agent for cancer therapy without the cytotoxic effect of normal cells. Prior to surface-functionalizing GNPs, the cytotoxicity of the nanoparticles was evaluated, followed by their biocompatibility. PTX, an anticancer agent, formed inclusion complexations with β-CD conjugated GNPs, and effectively released from the GNP-2ʹ surface-functionalized with PEG, β-CD and PTX using the intracellular glutathione (GSH) level (10 mM). Two types of GNPs-4 surface-functionalized with PEG and rhodamine B linked β-CD and 5 were used for evaluating their specific interaction on cancer cells such as HeLa, A549 and MG63. These were also tested against normal NIH3T3 cell determining that the GNP-5 was more effectively involved with the cancer cells. Confocal laser scanning microscopy (CLSM), fluorescence-activated cell-sorting (FACS) and cell viability analyses showed that the GNP-5ʹ plays a significant role in the diagnosis and therapy of the cancer cells at the same time such as theranostic agents.
The aim of Chapter 2 was to develop a new approach for bone tissue regeneration based on the utilization of biodegradable hydrogel loaded with GNPs. We have used photo-curable gelatin hydrogels (Gel) in order to provide a proof of principle of GNPs in regeneration strategies for bone tissue repair. We have investigated the effects of these Gel-GNP composite hydrogels both in vitro and in vivo. The in vitro results showed that the hydrogels loaded with GNPs promote proliferation, differentiation, and alkaline phosphate (ALP) activities of ADSCs as they differentiate towards osteoblast cells in dose-dependent manner. Moreover, the in vivo results showed that these hydrogels loaded with a high concentrations of GNPs had a significant influence on new bone formation. Through these in vitro and vivo tests, we found that the Gel-GNP can be a useful material for bone tissue engineering.
GNPs have been previously reported to inhibit osteoclast (OC) formation. However, the precise biological mechanisms which drive this inhibitory effect towards OC differentiation remain unclear.
In Chapter 3, we prepared functionalized GNPs covered with β-CD/curcumin (CUR) inclusion complex (CUR-CGNPS), and used these to investigate the inhibitory effect and biological mechanisms on the receptor activator of nuclear factor- κb ligand (RANKL)-induced osteoclastogenesis in bone marrow-derived macrophages (BMMs). The CUR-CGNPs significantly inhibited the formation of tartrate-resistant acid phosphatase (TRAP)-positive multinuclear cells in BMMs without cytotoxicity. The mRNA expression of c-Fos, nuclear factor of activated T cells 1 (NFATc1), TRAP, and osteoclast associated receptor (OSCAR), which are genetic markers of OC differentiation, were significantly decreased in the presence of CUR-CGNPs. Also, the CUR-CGNPs inhibited OC differentiation of BMMs through suppression of the RANKL-induced signaling pathway. Additionally, CUR-CGNPs caused a decrease in RANKL-induced actin ring formation, which is an essential morphological characteristic of OC allowing them to carry out bone resorption activity. Therefore, CUR-CGNPs may prove to be useful as novel therapeutic agents for preventing and treating osteoporosis.