No description available.

Nanomedicine, the medical application of nanotechnology, uses nanoscale objects that exist at the interface between small molecule and the macroscopic world for medical diagnosis and treatment. One of the healthcare applications of nanomedicine is drug delivery: the development of nanoscale objects to improve therapeutics' bioavailability and pharmacokinetics. Shell crosslinked knedel-like nanoparticles (SCKs), that are self assembled from amphiphilic block copolymers into polymeric micelles and then further stabilized with crosslinkers isolated throughout the peripheral shell layer, have been investigated for drug delivery applications that take advantage of their core-shell morphology and tunable surface chemistry. SCKs are attractive nanocarriers because the cores of the SCKs are used for sequestering and protecting guests. The readily adjustable shell crosslinking density allows for gating of the guest transport into and out of the core domain, while retaining the structural integrity of the SCKs. Moreover, the highly functionalizable shell surface provides opportunity for incorporation of targeting ligands for enhanced therapeutic delivery. The optimization of nanoparticle size, surface chemistry, composition, structure, and morphology has been pursued towards maximization of the SCKs' therapeutic efficacy. With distinctively different dimensions, compositions and structures of the core and shell domains of SCKs, and an ability to modify each independently, probing the effects of each is one of the major foci of this dissertation. Utilization of a living radical polymerization technique, reversible addition-fragmentation chain transfer (RAFT) polymerization, has allowed for facile manipulation of the block lengths of the polymer precursors and thus resulted in various dimensions of the nanoparticles. SCKs constructed from poly(acrylic acid)-b-polystyrene (PAA-b-PS) with various chain lengths, have been investigated on the loading and release of doxorubicin (DOX). The effect of PEGylation on paclitaxel (PTX) loaded SCKs on the cell internalization and killing was investigated. Apart from chemotherapies, the SCKs were explored as antimicrobial agents by incorporating silver species. Conjugation of the SCK surface with a protein adhesin through amidation chemistry to promote epithelial cell targeting and internalization was developed. Nanoscale assemblies with complex morphologies constructed from a linear triblock copolymer was investigated. Furthermore, a highly multifunctional nanodevice for imaging and drug delivery functionalized with a chelator for radio-labeling, polyethylene glycol (PEG) for improved biodistribution, targeting ligands, a chromophore and a therapeutic agent was evaluated in vivo as active-targeted delivery of therapeutics.

Immuno-nanoparticles of poly(ᴅ,ʟ-lactide-co-2-methyl-2-carboxytrimethylene carbonate)-g-poly(ethylene glycol) (poly(LA-co-TMCC)-g-PEG) have been used to target breast cancer cells through the specific binding of trastuzumab antibodies to over-expressed human epidermal growth factor receptor 2 (HER2). Small interfering RNA (siRNA) and antisense oligonucleotides (AONs) disrupt the synthesis of select proteins. It is hypothesized that oligonucleotides coupled to polymeric immuno-nanoparticles can be used for gene silencing and specifically to target luciferase. The first objective is to demonstrate the capacity to create dual functional micelles with antibodies and oligonucleotides. The second objective is in vitro testing of the nanoparticle for gene silencing activity. Oligonucleotides are conjugated to the nanoparticle by sequential click reactions of Diels Alder chemistry and copper catalyzed azide-alkyne cycloadditions, respectively. A luciferase assay is used to quantify knockdown of luciferase levels in SKOV-3luc cells (HER2+, luc+). When used in conjunction with a targeted drug delivery vehicle, the nanoparticles provide selective interactions with SKOV-3luc cells.

Immuno-nanoparticles of poly(ᴅ,ʟ-lactide-co-2-methyl-2-carboxytrimethylene carbonate)-g-poly(ethylene glycol) (poly(LA-co-TMCC)-g-PEG) have been used to target breast cancer cells through the specific binding of trastuzumab antibodies to over-expressed human epidermal growth factor receptor 2 (HER2). Small interfering RNA (siRNA) and antisense oligonucleotides (AONs) disrupt the synthesis of select proteins. It is hypothesized that oligonucleotides coupled to polymeric immuno-nanoparticles can be used for gene silencing and specifically to target luciferase. The first objective is to demonstrate the capacity to create dual functional micelles with antibodies and oligonucleotides. The second objective is in vitro testing of the nanoparticle for gene silencing activity. Oligonucleotides are conjugated to the nanoparticle by sequential click reactions of Diels Alder chemistry and copper catalyzed azide-alkyne cycloadditions, respectively. A luciferase assay is used to quantify knockdown of luciferase levels in SKOV-3luc cells (HER2+, luc+). When used in conjunction with a targeted drug delivery vehicle, the nanoparticles provide selective interactions with SKOV-3luc cells.

Polymeric nano and microparticles are important tools for an increasing variety of applications in the life sciences such as cellular delivery, sensing and imaging, with a fundamental requirement being particle functionalisation. Herein, the use of zeta potential measurements is described as a convenient tool to allow a variety of chemical reactions to be rapidly monitored on particles. To allow multifunctionalisations these particles need to be orthogonally modified. As part of this thesis, novel dual-functionalised aminomethyl and boronic acid particles were synthesised. These particles could be modified via amide formation and palladiummediated cross coupling, with applications demonstrated in cellular delivery and cellbased cargo release. The requirement for bright fluorescent particles for applications in the life sciences was addressed by the synthesis and analysis of particles prepared using polymerisable fluorescein derivatives. Although nanoparticles are a promising technology to solve a variety of problems, their behaviour in biological systems is not fully understood. Herein, the effects of the particle’s surface chemistry on cellular uptake and toxicity were investigated.

The aims of this thesis were two-fold: A) To use high internal phase emulsion (HIPE) templated materials to produce a chromatographic stationary phase for the size separation of engendered nanoparticles (NPs). B) To produce well characterised lanthanide doped polymer NPs with a potential use as analytical standards. Initially, silica materials were prepared from oil-in-water HIPEs by a two stage acid/base catalysed sol gel process. As well as presenting the expected macroporosity typical of HIPE templated materials, it was also found that micro- and meso-porosity could be influenced by surfactant choice and reaction with iron (III) chloride or copper (I) chloride which had been included in the HIPE. However, the resulting silica materials were deemed inappropriate for the desired chromatography. Monolithic columns were prepared from HIPE templated polymers (polyHIPEs) and incorporated into a HPLC system. Poly(styrene-co-divinylbenzene) and poly(ethylene glycol dimethacrylate) polyHIPE columns were able to separate sub-micron polystyrene latexes, detected by UV absorption, and dysprosium doped polystyrene latex particles and gold nanoparticles detected by inductively coupled plasma mass spectrometry (ICP-MS).Dysprosium, gadolinium and neodymium doped polystyrene NPs were prepared by micro-emulsion polymerisation. Particle size was controlled (over a 40 – 160 nm range) by tailoring of surfactant and initiator concentrations. Particles were characterised by dynamic light scattering, differential centrifugal sedimentation, transition electron microscopy and hydrodynamic chromatography (HDC)-ICP-MS. Also, particle surface change, lanthanide content and solids content were analysed. The latter two appear related to particle size. As far as the author is aware there are no cases of the use of polyHIPE columns size separation in the literature. Nor are there any cases of encapsulation of metals within polymer nanoparticles by micro-emulsion polymerisation reported.

Nanoparticles have the potential to revolutionize medicine, but many obstacles complicate the translation of nanoparticles from the bench to the clinic. A deeper understanding of nanoparticle synthesis parameters that influence nanoparticle size, drug loading, and surface chemistry is needed to accelerate the design of efficacious therapeutic nanoparticle systems. In this work, organic and inorganic nanoparticles were prepared with hydrodynamic diameters below 200 nm for applications in cancer treatment and immunology. Hydrophobic ion pairing was applied to enhance the loading capacity of drugs and peptides in polyester and polysaccharide nanoparticles systems. Polyester nanoparticles were successfully functionalized with streptavidin-Cy3, interferon gamma (IFN-γ), and CX3CL1. Poly(methacrylic acid), chitosan, and polyinosinic-polycytidylic acid (poly(I:C)) were successfully adsorbed to the surfaces of nanoparticles to enhance particle stability and targeting. Iron-based coupling media capable of eliminating ~ 90% of the water signal from an acoustic coupling bath during gradient echo magnetic resonance imaging (MRI) thermometry was successfully designed using magnetic iron oxide nanoparticles to improve the clinical efficacy of MRI-guided focused ultrasound surgery (MRI-FUS). While the critical nanoparticle design criteria may change depending on the biomedical application, fundamental concepts of nanoparticle design and synthesis can be applied across applications. The projects presented here help to bridge the knowledge gap regarding the use of flash nanoprecipitation (FNP) for nanoparticle synthesis. FNP is a scalable nanoparticle fabrication method that produces small, well-defined nanoparticle populations through rapid, turbulent mixing of multiple solvent streams. This work elucidates nanoparticle design concepts that can be applied across a wide variety of biomedical applications. / Doctor of Philosophy / Cancer remains a critical public health issue worldwide because many promising therapies never make it from the lab into the hospital. Many chemotherapeutic drugs are hindered by poor solubility and serious, undesirable side effects. In the past few decades, new production techniques have been developed to create carriers for these drugs to help overcome these obstacles. These carriers can be made from a variety of materials including metals and biodegradable polymers. In fact, it is even possible to create "smart" carriers that react to their environment to travel within the body or release the drugs they contain. Understanding how to design these carriers for different biomedical applications is critical. This work shows how carriers made from metal or polymer can be designed to exhibit desirable characteristics for use in biomedical applications ranging from vaccines to cancer treatment. Various ways to modify the surfaces of these carriers to tailor them for different applications are presented. This work provides valuable information that can help drive the next generation of biomedical innovation.

No description available.

In this thesis, I used a two-phase gas-liquid segmented microfluidic platform to synthesize drug-loaded block copolymer nanoparticles. In Chapter 2 and 3, the anti-cancer drug 7-ethyl-10-hydroxycamptothecin (SN-38) was physically encapsulated in poly(6-methyl-caprolactone-co-ε-caprolactone)-block-poly(ethylene oxide) (P(MCL-co-CL)-b-PEO) nanoparticles with various drug-to-polymer loading ratios, under different flow conditions. The effects of chemical and flow conditions on the size, morphology, drug loading efficiency, in vitro release and cytotoxicity of the nanoparticles were determined. For various loading ratios, the intermediate total flow rate (Q = 200 µL/min) produced the smallest nanoparticle sizes and pure spheres. The various nanoparticle preparation conditions showed flow-variable release rates and cytotoxicities against MCF-7 cancer cell line. Specifically, we found that release half times of SN-38 from the nanoparticles were from τ1/2 = 0.8 to 3.3 h as the total flow rate increased from Q = 50 to 200 µL/min. We also found that most conditions of SN-38 formulations generated stronger cytotoxicity than free SN-38. As well, at short and intermediate incubation time (48 and 72 h), the cytotoxic potency of microfluidic nanoparticles prepared at Q = 200 µL/min were slightly higher than nanoparticles prepared using a conventional bulk method, while potencies of microfluidic nanoparticles prepared at higher and lower flow rates were slightly lower than the bulk control. In Chapter 4, in order to pursue even higher shear rate and increased throughput, we switched the microfabrication material to silicon/glass from polydimethylsiloxane (PDMS) used in earlier chapters, maintaining the gas-liquid microfluidic reactor design. A comparison between the two microfluidic reactor materials at constant liquid flow rate showed that channel material affected both flow behaviour and the resulting nanoparticle morphologies. A new, single-phase microfluidic strategy was also proposed in order to generate high shear, in which variable high and low shear would arise from periodic changes in channel dimensions. However, issues regarding clogging of the more narrow microchannels require future work of improvements in either reactor design or the microfabrication process. / Graduate / 2019-01-12

The potential use of polymeric, functionalized nanoparticles (NPs) as drug delivery vectors was explored. Covalent conjugation of albumin to the surface of NPs via maleimide chemistry proved problematic. However, microwave assisted synthesis of NPs was not only time efficient, but enabled the exploration of size control by changing the following parameters: temperature, microwave power, reaction time, initiator concentration, and percentage of monomer used. About 1.5 g of fluorescently-labeled, carboxylic acid-functionalized NPs (100 nm diameter) were synthesized for a total cost of less than $1. Future work will address further functionalization of the NPs for the coupling of albumin (or other targeted proteins), and tests for in vivo biodistribution.