Streptococcus pneumoniae is typically an asymptomatic colonizer of the upper respiratory tract but can cause invasive disease in susceptible populations. Pneumococcal vaccines which are currently in use have failed to significantly reduce colonization by S. pneumoniae. To control invasive pneumococcal disease, novel strategies must be utilized. One such strategy is to reduce or eradicate colonization by pneumococcus. Supplementary vaccination with pneumococcal proteins important for colonization could serve to prime the immune system against these targets. This study serves as an initial step towards identification of crucial pneumococcal colonization proteins which may previously have been uncharacterized. Assessing the immune reactivity of human serum to isolated pneumococcal membrane proteins allowed for selection of proteins for analysis via mass spectrometry. Results of MS produced several potential protein targets for further research. Identification of these key surface proteins will pave the way for the creation of a more robust supplementary vaccine, and an improved understanding of the role of non-immunogenic pneumococcal surface proteins.

Nanotechnology and its potential for biomedical applications has become an area of increasing interest over the last few decades. Specifically, ultrasmall nanoparticles, ranging in size from 5 to 50 nm, are highly sought after for their physical and chemical properties and their ability to be easily transmitted though the bloodstream. By adjusting the material properties, size, surface potential, morphology, surface modifications, and more, of nanoparticles, it is possible to tailor them to a specific use in biomedical areas such as drug and gene delivery, biodetection of pathogens or proteins, and tissue engineering. The aim of this study was to fabricate ultrasmall poly-(lactic-co-glycolic acid) nanoparticles (PLGA NPs) using a quick and easy nanoprecipitation method1, with some modifications, for general use in various biomedical areas. Nanoprecipitation of two solutions – PLGA dissolved in acetonitrile and aqueous poly(vinyl alcohol) (PVA) – at varying concentrations produced ultrasmall nanoparticles that range in size, on average, from 10 to 30 nm. By the data collected from this study, a selection method can be used to choose a desired PLGA nanoparticle size given a potential biomedical application. The desired nanoparticle can be fabricated using specific concentrations of the two nanoprecipitation solutions. Size of the ultrasmall PLGA NPs was characterized by dynamic light scattering (DLS) and confirmed by transmission electron microscopy (TEM). Spherical morphology of the PLGA NPs was also proved by TEM. By generalizing the ultrasmall PLGA NP fabrication process, the idea is that these NPs will be able to be used in various biomedical applications depending on the goal of the furthered study. As an example of potential application, ~15 to 20 nm PLGA NPs were consistently fabricated for use as virus-like particle (VLP) scaffolds. Following formation, PLGA NPs were introduced to modified human papillomavirus (HPV) protein during protein refolding and assembly into virus-like particles (VLPs) via buffer exchange. The size of the VLPs was monitored with and without PLGA nanoparticles present in solution during the refolding process and TEM images were collected to confirm encapsulation. / Master of Science / Nanotechnology, the manipulation of materials on an atomic or molecular scale, and its potential for biomedical applications has become an area of increasing interest over the last few decades. Nanoparticles, spherical or non-spherical entities of sizes approximately one-billionth of a meter, have been used to solve a wide variety of biomedical problems. For reference, a human hair is about 80,000 to 100,000 nm in size and the nanoscale typically ranges in size from 1 to 1000 nm. This size range is not visible to the naked eye, so methods of analysis via scientific equipment becomes paramount. Specifically, this study aims to fabricate ultrasmall nanoparticles, ranging in size from 5 to 50 nm, which are highly sought after for their physical and chemical properties and their ability to easily travel though the bloodstream. By adjusting the material properties, size, shape, surface charge, surface modifications, and more, of nanoparticles, it is possible to tailor them to a specific use in biomedical areas such as drug delivery, detection of viruses, and tissue engineering. The specific aim of this study was to fabricate ultrasmall poly-(lactic-co-glycolic acid) nanoparticles (PLGA NPs), a type of polymer, using a quick and easy nanoprecipitation method1, with some modifications. Nanoprecipitation occurs by combining two liquid solutions – PLGA and aqueous poly(vinyl alcohol) (PVA) – which interact chemically to form a solid component – a polymer nanoparticle. These two solutions, at varying concentrations, produced ultrasmall nanoparticles that range in size, on average, from 10 to 30 nm. Data collected from this study can be used to select a desired nanoparticle size given a potential application. The desired nanoparticle can be fabricated using specific concentrations of the two nanoprecipitation solutions. By generalizing the ultrasmall PLGA NP fabrication process, the idea is that these NPs can be used for a variety of biomedical applications depending on the goal of the furthered study. Two PLGA NP example applications are tested for in this work – in DNA loading and in encapsulation of virus-like particles (VLPs), which are synthetically produced proteins that can be neatly folded to resemble a virus. These VLPs can be used to as an alternative to live vaccines and they can be designed to stimulate the immune system. Positive initial results from this study confirm the potential of these nanoparticles to have a wide impact on the biomedical field depending on specific tailoring to a given application.