A Espectroscopia Raman Intensificada pela Superfície (SERS) é um efeito de intensificação da intensidade Raman de uma molécula adsorvida numa superfície metálica nanoestruturada. Esta característica permite a utilização do SERS na caracterização vibracional de sistemas como junções moleculares (JM) (JM são sistemas constituídos de fios moleculares sintetizados em junções do tipo metal|fiomolecular|metal) e, no entendimento de quais características morfológicas de agregados metálicos mais influenciariam no sinal SERS obtido. Portanto, esta tese apresenta os seguintes objetivos: (a) síntese e caracterização de substratos SERS ativos, nanoesferas (AuNE) e nanobastões (AuNB) de ouro e eletrodo de ouro ativado eletroquimicamente; (b) síntese e caracterização SERS de fios moleculares em JM; (c) estudo do acoplamento plasmônico entre as superfícies metálicas em JM; (d) correlação entre SERS - morfologia de agregados individuais de AuNB. Os fios moleculares estudados foram os da família das oligofeniliminas (OPI) e, no melhor do nosso entendimento, esta foi a primeira vez que fios moleculares desta família foram caracterizados por Raman e SERS. As JM apresentaram um comportamento SERS não esperado. Enquanto para o modo vibracional, v(CS), a intensidade da banda se apresentou constante com o aumento do espaçamento entre as nanoestruturas metálicas (para distâncias de até 5 nm), o modo vibracional, β(CH), teve a intensidade de sua banda aumentada. Este comportamento foi explicado considerando a diferente natureza da interação dos plasmons nas JM, sendo estas interações do tipo, ressonância de plasmon de superfície (LSPR) - dipolo imagem, para ambos os modos. No entanto, para o modo β(CH) existe também uma intensificação extra devido ao aumento da polarizabilidade dos fios moleculares com o aumento do número de unidades. A correlação SERS - morfologia dos agregados de AuNB indicam que, para agregados onde predominam interações ponta a ponta, os espectros SERS apresentavam uma maior intensidade quando comparados com aqueles em que interações lado a lado predominavam. No entanto, este comportamento não foi observado para agregados contendo mais do que cinco nanopartículas onde estes dois tipos de interações ocorrem indicando que deve existir um acoplamento dos plasmons destes dois tipos de interações contribuindo para maiores valores de intensidade SERS. / Surface enhanced Raman Spectroscopy (SERS) is a Raman enhancing effect of molecules adsorbed on nanostructured metal surfaces. This characteristic allows the use of SERS in the vibrational study of Molecular Junction systems (MJ) (MJ is a system formed by Molecular Wires (pi-conjugated molecules) synthesized in metal junctions like metal|molecular-wire|metal). In addition, we can also use SERS to understand the influence of morphological characteristic of gold nanostructures. This thesis aims: (a) synthesis and characterization of gold nanospheres (AuNS), nanorods (AuNR) and gold electrode (electrochemically activated); (b) synthesis and vibrational studies of molecular wires in JM; (c) plasmon coupling studies between flat surface and gold nanorods; (d) correlation SERS - AuNR morphology of individual aggregates. For the best of our knowledge, this was the first time that oligophenilenelimine (OPI) as molecular wire was characterized by Raman and SERS. The MJ showed an unusual behavior such that the v(CS) vibrational mode remained constant in intensity with the increasing of the gap spacing (within 5 nm) while the β(CH) increased with the increase of the gap. This behaviour was related to the different nature of the interaction between plasmons resonances in JM (surface plasmon resonance (LSPR) - dipole image) for the first case and due to chemical contributions by the molecular wires for the second vibrational mode. The results for SERS - morphology AuNR aggregates correlation showed (for small aggregates) that when in the aggregate predominated end-by-end interaction SERS spectra showed a higher intensity when compared to those in which interactions side-by-side predominated. Although, this behavior was not observed for aggregates containing more than five nanoparticles indicating that there is not a preferential interaction between the nanorods for such aggregates and that a mixture of both will be preferable for large SERS intensities.

Determination of bio-material by using enzyme, fluorophore or metal-nanoparticles as markers is very important. Generally, gold-nanoparticles have been used frequently as marker for increasing the sensitivity in bio-chemical assay. In this research, gold-nanoparticles were used as marker for immunoassay, DNA sequence assay, and protein analysis. However, the size of gold-nanoparticles affects directly the results of electrochemical detection. For improving the sensitivity of electrochemical method, enlargement of gold-nanoparticles was used in this study. By electroless deposition, Au will be deposited on the surface of gold-nanoparticles. The electrochemical response will thus be increased substantially. In immunoassay and DNA sequence assay, traditional 96-wells microtiter plate was used for immobilizing antibody or oligonucleotide, and the gold-nanoparticles were marked subsequently base on the immunoreaction or protein reaction of streptavidin and biotin. After gold-nanoparticles were enlarged, they were dissolved and transferred to an electrochemical cell for square wave stripping voltammetry¡]SWSV¡^analysis. Under optimal experimental condition, dynamic range of 1 ~ 500 pg/mL and 0.52 ~ 1300 aM were found respectively for RIgG and Target DNA analysis, and a good linear relationship¡]R2 = 0.9975 and 0.9982¡^. The relative standard deviation¡]R.S.D.¡^ of blank were 2.8 % and 2.4 %¡]n = 11¡^for immunoassay and DNA assay, respectively. And the variance was 2.4 %¡]n = 9¡^and 2.4 %¡]n = 12¡^for immunoassay and DNA assay, respectively. The detection limit¡]based on S/N = 3¡^of RIgG and DNA were 0.25 pg/mL and 0.52 aM, respectively. They are very competitive compared with similar results reported in the literature. Additional, a gold nanoelectrode ensemble¡]GNEE¡^coupled microchip system was developed for bio-electrochemical analysis. Due to the difference in mobility of urea and urease were mixed and allowed the enzymatic reaction to proceed in microchannel. The enzymatic product NH4+ was determined by the coupled GNEE at the outlet of the channel. Another experiment of streptavidin conjugated gold-nanoparticles¡]streptavidin-Au¡^, reductant and gold-ion¡]Au3+¡^solution was be applied here, too. The product, NH4+ or Au3+ was passed through downstream of microchannel and detected by GNEE of electrochemical system. Satisfactory linear relationship¡]R2 = 0.9778 and 0.9657¡^were found from 0.1 mM to 50 mM for NH4+ and urea in the range of 0.02 mM to 5.0 mM, respectively. The other satisfactory linear relationship¡]R2 = 0.9842 and 0.9507¡^ were found between 3.75 mg/mL and 3.75 g/mL for Au3+ and streptavidin-Au in the range of 0.2 ng/mL to 100 ng/mL, respectively. Variances of 2.5 %¡]n = 6¡^was found for analysis of with the microchip system.

Gold nanoparticle has emerged as an attractive platform for drug delivery applications by complementing the existing drug delivery carriers. Currently, only a few gold nanoparticle-based anticancer drug delivery systems have been reported, compared to the polymer-based delivery systems. Additionally, there is still a lack of understanding for the behavior and fate of the gold-drug conjugate in the body that further attention is required. The overall goal of this thesis is to investigate the in vivo behavior of colloidal gold nanoparticle and its therapeutic efficacy in an animal model, especially in a drug delivery application. To achieve this goal, we investigated the feasibility of using colloidal gold nanoparticle as an anticancer agent delivery vehicle for treatment of cancer. Then, long-term clearance, toxicity, and biodistribution of colloidal gold nanoparticle were studied to further aid in understanding of using colloidal gold nanoparticle as a drug delivery platform. In particular, two representative sizes of gold nanoparticles, 5nm and 60nm, were investigated for the size effect on the therapeutic efficacy, toxicity, biodistribution, and clearance in cancer nanotherapy. We believe that nanoparticle size plays a critical role in not only delivering the drug to the target site but also determining the in vivo behavior such as biodistribution and clearance. By choosing an appropriate size scale for the system, we successfully used the small-sized gold nanoparticles for drug delivery applications, which also displayed no apparent toxicity with desirable clearance from the biological system. This work is significant by providing an insight on a potential ideal candidate for drug delivery carrier for cancer nanotherapy.

Poly(3,4-ethylenedioxythiophene), PEDOT, belongs to the group of conducting polymers and is characterized by its high stability, a moderate band gap and its optical transparency in the conductive state. A large disadvantage of conducting polymers, and also PEDOT, is their poor solubility. One way to achieve processible materials is the synthesis of colloidal particles. Thus, this work focuses on the development of conductive particles by preparing composite structures. Polymeric colloids like latex particles and microgels were used as templates for the oxidative polymerization of EDOT. Depending on template structure completely different composite morphologies with variable properties were obtained. It was found that modification with PEDOT did not only cause conductive particles for application as humidity sensor materials, but also candidates for further functionalization with gold nanoparticles (Au-NPs). Due to a multi-stage synthesis route it was possible to achieve polystyrene(core)-PEDOT(shell)-particles decored with Au-NPs. Microgels acting as “micro reactors” for the incorporation of PEDOT and Au-NPs were also used for preparing multifunctional composites for catalytic applications. / Poly(3,4-ethylendioxythiophen), PEDOT, gehört zur Gruppe der leitfähigen Polymere und zeichnet sich durch seine hohe Stabilität, eine moderate Bandlücke und seine optische Transparenz im dotierten Zustand aus. Ein Nachteil leitfähiger Polymere, wie auch von PEDOT, ist deren schlechte Löslichkeit. Die Synthese kolloidaler Partikel bietet jedoch eine Möglichkeit dieses Problem zu umgehen. In diesem Zusammenhang richtete sich der Fokus dieser Arbeit auf die Darstellung leitfähiger Partikel in Form von Kompositstrukturen. Polymerkolloide, wie Latex- und Mikrogelpartikel, sind als Template eingesetzt worden, in deren Gegenwart PEDOT durch eine oxidative Polymerisation synthetisiert wurde. In Abhängigkeit von der Struktur des Templats sind unterschiedliche Kompositmorphologien mit steuerbaren Eigenschaften erhalten worden. Auf diese Weise wurden neben Materialien für die Feuchtigkeitssensorik leitfähige Kompositpartikel hergestellt, die zusätzlich mit Gold-Nanopartikeln (Au-NP) funktionalisiert werden konnten. Durch ein mehrstufiges Syntheseverfahren sind somit Polystyrol(Kern)-PEDOT(Schale)-Partikel mit Au-NP-funktionalisierter Oberfläche synthetisiert worden. Mikrogelpartikel, die als „Mikroreaktoren“ für die Inkorporation von PEDOT- und Au-NP dienten, wurden ebenfalls eingesetzt, um multifunktionale Komposite mit katalytischen Eigenschaften herzustellen.

Acute lung injury (ALI) is a major cause of mortality after lung transplantation. Recent studies indicate protein kinase C delta (PKCδ) could be an effective target to treat ALI. We have developed a gold nanoparticle (GNP)-peptide hybrid that can inhibit PKCδ signaling. PKCδ inhibitor peptide (PKCi) and 95P2P4 stabilizing peptides were conjugated onto GNP. Physicochemical properties of the nanoformulations were examined. A lung transplant-simulated cell culture model was used to evaluate therapeutic efficacy in vitro. A pulmonary ischemia-reperfusion (IR) model was used to test therapeutic efficacy in vivo. GNP-Peptide hybrids showed good stability with high cellular uptake. GNP-PKCi formulations demonstrated anti-inflammatory and anti-apoptotic effects in vitro. When administered to rats under IR stress, GNP-PKCi formulation improved blood oxygenation, reduced pulmonary edema and histological lung injury. In conclusion, we have successfully formulated a clinically-applicable nanoparticle with therapeutic potential to ameliorate lung injury and inflammation. Our formulation strategy could be used to deliver other peptide-based drugs.

Acute lung injury (ALI) is a major cause of mortality after lung transplantation. Recent studies indicate protein kinase C delta (PKCδ) could be an effective target to treat ALI. We have developed a gold nanoparticle (GNP)-peptide hybrid that can inhibit PKCδ signaling. PKCδ inhibitor peptide (PKCi) and 95P2P4 stabilizing peptides were conjugated onto GNP. Physicochemical properties of the nanoformulations were examined. A lung transplant-simulated cell culture model was used to evaluate therapeutic efficacy in vitro. A pulmonary ischemia-reperfusion (IR) model was used to test therapeutic efficacy in vivo. GNP-Peptide hybrids showed good stability with high cellular uptake. GNP-PKCi formulations demonstrated anti-inflammatory and anti-apoptotic effects in vitro. When administered to rats under IR stress, GNP-PKCi formulation improved blood oxygenation, reduced pulmonary edema and histological lung injury. In conclusion, we have successfully formulated a clinically-applicable nanoparticle with therapeutic potential to ameliorate lung injury and inflammation. Our formulation strategy could be used to deliver other peptide-based drugs.

A incorporação de nanopartículas metálicas em tecidos tumorais tem sido estudada em Radioterapia devido ao aumento de dose que pode ser obtido no volume alvo do tratamento. Estudos indicam que nanopartículas de ouro (AuNP) estão entre as de maior viabilidade biológica para essas aplicações, devido ao baixo potencial tóxico. Além disso, estudos mostram que AuNP de alguns nanômetros até alguns micrômetros podem permear vasos sanguíneos que alimentam tumores, permitindo sua incorporação nas células tumorais. Desta forma, este trabalho visou estudar os fatores de aumento de dose obtidos em Radioterapia com AuNP incorporadas ao tecido tumoral utilizando feixes de ortovoltagem, de braquiterapia e de teleterapia. Este trabalho utilizou de uma metodologia computacional, através de simulação Monte Carlo com o código PENELOPE. Foram simulados feixes clínicos de 50, 80, 150 e 250 kVp, Ir-192 e 6 MV, e um modelo de célula tumoral com AuNPs incorporadas com diferentes concentrações de ouro. O modelo de células utilizado possui 13 µm de diâmetro externo máximo e 2 µm de diâmetro no núcleo. Dois modelos de incorporação de AuNPs foram implementados: modelo homogêneo e modelo heterogêneo. No modelo homogêneo, as AuNP foram distribuídas homogeneamente no núcleo e as células foram irradiadas nas diferentes energias estudadas para avaliar o fator de aumento de dose (DEF) em função da concentração de ouro na célula e da energia do feixe. No modelo heterogêneo, aglomerados de AuNPs foram simulados individualmente dentro da célula. Neste modelo foram utilizados somente os espetros de radiação que apresentaram os melhores desempenhos no modelo homogêneo. Foram avaliadas a fluência de partículas ejetadas nas AuNPs, o DEF, as distribuições de doses e os perfis de dose com aglomerados de 50 a 220 nm na célula. Os resultados obtidos para o modelo homogêneo mostram que os feixes de baixa energia são os que proporcionam maior DEF para uma mesma concentração de AuNP. Os maiores DEFs obtidos foram de 2,80; 2,99; 1,62 e 1,61, para os feixes de 50 kVp, 80 kVp, 150 kVp, 250 kVp, respectivamente, sendo a maior incerteza de 1,9% para o feixe de 250 kVp. Através dos resultados obtidos com o modelo heterogêneo foi possível concluir que os elétrons ejetados possuem maior influência no aumento local da dose. Os perfis de dose, extraídos das distribuições de doses, para os aglomerados simulados permitiram obter os alcances das isodoses de 50, 20 e 10% da dose no entorno das AuNPs. Através desses perfis de dose pode-se concluir que o aumento de dose é local, da ordem de alguns micrômetros, dependendo do tamanho das nanopartículas e da energia do feixe primário. Para o feixe de 50 kVp, o DEF encontrado para uma incorporação heterogênea de seis aglomerados de AuNPs, correspondendo a um modelo clínico real, foi de 1,79, com incerteza de 0,4%. Com base nos resultados obtidos pode-se concluir que as energias de ortovoltagem proporcionam maior fator de aumento de dose que feixes de megavoltagem utilizados em teleterapia convencional. Além disso, o reforço local de dose pode proporcionar um fator de radiossensibilização celular se as AuNPs forem incorporadas no núcleo das células, nas redondezas do DNA, proporcionando um maior potencial de controle tumoral. / The incorporation of metal nanoparticles into tumor tissues has been studied in radiation therapy given of the dose enhancement that can be obtained in the target volume of the treatment. Studies indicate that gold nanoparticles (AuNP) are among the highest biologically viable for such applications, due to their low toxic potential. In addition, studies show that AuNP from a few nanometers to a few micrometers can permeate blood vessels that feed tumors, allowing their incorporation into tumor cells. Hence, this study´s goal was to study the dose enhancement factors obtained in radiation therapy with AuNP incorporated in the tumor using orthovoltage, brachytherapy and teletherapy beams. This work used a computational methodology, through Monte Carlo simulation with the PENELOPE package. Clinical beams of 50, 80, 150 and 250 kVp, Ir-192 and 6 MV were simulated with a tumor cell model with incorporated AuNPs. The cell model has maximum outer diameter of 13 m and 2 m of nucleus diameter. Two models of AuNP incorporation were implemented: homogeneous model and heterogeneous model. In the homogeneous model the AuNP were distributed homogeneously in the nucleus and the cells were irradiated in the different beams studied to evaluate the dose enhancement factors (DEF) as a function of concentration of gold in the cell and radiation beam. In the heterogeneous model, clusters of AuNPs were simulated individually within the cell. In this model, the radiation spectra used was selected among those that presented the best performances in the homogeneous model. The fluence of particles ejected from the AuNPs, the DEFs, the dose distributions and dose profiles for clusters of 50 to 220 nm in the cell were evaluated. The results obtained for the homogeneous model show that lower energy beams provide the highest DEFs for the same concentration of AuNP. The highest DEFs obtained were 2.80; 2.99; 1.62 and 1.61, for the beams of 50 kVp, 80 kVp, 150 kVp, 250 kVp, respectively, with a maximun uncertainty of 1.9% for the 250 kVp beam. Through the results obtained with the heterogeneous model it was possible to conclude that the electrons ejected from he AuNPs have the major influence on the local dose enhancement. The dose profiles extracted from the dose distributions for the simulated clusters allowed the evaluation of the ranges for the 50, 20 and 10% isodoses in the surroundings of the AuNPs. Through these dose profiles, it can be concluded that the dose increase is local, in the order of a few micrometers, depending on the size of the nanoparticles and the energy of the primary beam. For the 50 kVp beam, the DEF found for a heterogeneous incorporation of six clusters of AuNPs, corresponding to an actual clinical model, was 1.79, with uncertainty of 0.4%. Based on the results obtained it can be concluded that kilovoltage energies provide a higher dose enhancement factor than megavoltage beams used in teletherapy. In addition, local dose enhancement may provide a cellular radiosensitization factor if the nanoparticles are incorporated in the nucleus of the cells, in the vicinity of the DNA, providing an enhanced potential for tumor control.

A Espectroscopia Raman Intensificada pela Superfície (SERS) é um efeito de intensificação da intensidade Raman de uma molécula adsorvida numa superfície metálica nanoestruturada. Esta característica permite a utilização do SERS na caracterização vibracional de sistemas como junções moleculares (JM) (JM são sistemas constituídos de fios moleculares sintetizados em junções do tipo metal|fiomolecular|metal) e, no entendimento de quais características morfológicas de agregados metálicos mais influenciariam no sinal SERS obtido. Portanto, esta tese apresenta os seguintes objetivos: (a) síntese e caracterização de substratos SERS ativos, nanoesferas (AuNE) e nanobastões (AuNB) de ouro e eletrodo de ouro ativado eletroquimicamente; (b) síntese e caracterização SERS de fios moleculares em JM; (c) estudo do acoplamento plasmônico entre as superfícies metálicas em JM; (d) correlação entre SERS - morfologia de agregados individuais de AuNB. Os fios moleculares estudados foram os da família das oligofeniliminas (OPI) e, no melhor do nosso entendimento, esta foi a primeira vez que fios moleculares desta família foram caracterizados por Raman e SERS. As JM apresentaram um comportamento SERS não esperado. Enquanto para o modo vibracional, v(CS), a intensidade da banda se apresentou constante com o aumento do espaçamento entre as nanoestruturas metálicas (para distâncias de até 5 nm), o modo vibracional, β(CH), teve a intensidade de sua banda aumentada. Este comportamento foi explicado considerando a diferente natureza da interação dos plasmons nas JM, sendo estas interações do tipo, ressonância de plasmon de superfície (LSPR) - dipolo imagem, para ambos os modos. No entanto, para o modo β(CH) existe também uma intensificação extra devido ao aumento da polarizabilidade dos fios moleculares com o aumento do número de unidades. A correlação SERS - morfologia dos agregados de AuNB indicam que, para agregados onde predominam interações ponta a ponta, os espectros SERS apresentavam uma maior intensidade quando comparados com aqueles em que interações lado a lado predominavam. No entanto, este comportamento não foi observado para agregados contendo mais do que cinco nanopartículas onde estes dois tipos de interações ocorrem indicando que deve existir um acoplamento dos plasmons destes dois tipos de interações contribuindo para maiores valores de intensidade SERS. / Surface enhanced Raman Spectroscopy (SERS) is a Raman enhancing effect of molecules adsorbed on nanostructured metal surfaces. This characteristic allows the use of SERS in the vibrational study of Molecular Junction systems (MJ) (MJ is a system formed by Molecular Wires (pi-conjugated molecules) synthesized in metal junctions like metal|molecular-wire|metal). In addition, we can also use SERS to understand the influence of morphological characteristic of gold nanostructures. This thesis aims: (a) synthesis and characterization of gold nanospheres (AuNS), nanorods (AuNR) and gold electrode (electrochemically activated); (b) synthesis and vibrational studies of molecular wires in JM; (c) plasmon coupling studies between flat surface and gold nanorods; (d) correlation SERS - AuNR morphology of individual aggregates. For the best of our knowledge, this was the first time that oligophenilenelimine (OPI) as molecular wire was characterized by Raman and SERS. The MJ showed an unusual behavior such that the v(CS) vibrational mode remained constant in intensity with the increasing of the gap spacing (within 5 nm) while the β(CH) increased with the increase of the gap. This behaviour was related to the different nature of the interaction between plasmons resonances in JM (surface plasmon resonance (LSPR) - dipole image) for the first case and due to chemical contributions by the molecular wires for the second vibrational mode. The results for SERS - morphology AuNR aggregates correlation showed (for small aggregates) that when in the aggregate predominated end-by-end interaction SERS spectra showed a higher intensity when compared to those in which interactions side-by-side predominated. Although, this behavior was not observed for aggregates containing more than five nanoparticles indicating that there is not a preferential interaction between the nanorods for such aggregates and that a mixture of both will be preferable for large SERS intensities.

Carbon nanotubes (CNTs) and gold nanoparticles (AuNPs) are widely used for sensing applications due to their distinctive electrical and optical properties, and we have explored the development of methods that enable the incorporation of these nanomaterials into new and improved sensing devices. As a means for fabricating simple, low-cost and fast detection platforms for various applications, we have developed paper-based electrochemical detection platforms based on CNTs or platinum nanoparticle (PtNP)-CNT composite materials. We describe the use of a paper-based, low density, a three-dimensional thin film of interconnected CNTs as an electrode material. We studied the electrochemical properties of these paper-based CNT electrodes and demonstrated their use as an electrochemical sensor for the sensitive detection of guanine-based nucleotides. We further describe the functionalization of this paper-based electrode by fabricating a PtNP-SWCNT hybrid film via a vacuum filtration-based method. The interconnected PtNP structure formed on top of the CNT-coated paper was directly used as an electrocatalyst for methanol oxidation. Compared to paper-based PtNP-SWCNT hybrid films formed by electrochemical deposition, hybrid films formed by vacuum filtration showed a higher electrochemical surface area and enhanced electrocatalytic response to methanol oxidation. We have also developed methods based around DNA-modified AuNPs, which offer an excellent colorimetric platform for target detection. The DNA density on the surface of modified AuNPs affects enzymatic activity, colloidal stability of AuNPs, the orientation of the probe DNA and its hybridization efficiency. The combination of all these factors ultimately dictates the reaction time and sensitivity of colorimetric assays. We demonstrate the use of DTT as a modulator to control DNA surface coverage on the surface of AuNPs. Using this DTT treatment and a novel probe for exonuclease III activity, we have developed a colorimetric assay based on DTT-treated, DNA-modified AuNPs that can achieve more sensitive and rapid detection of DNA and enzymes relative to existing sensor platforms.

The colloidal self-assembly of plasmonic gold nanoparticles (AuNPs) is of interest to utilize the plasmonic coupling effects that arise between nanoparticles. The enhanced properties of anisotropic AuNPs make them particularly attractive in self-assemblies. Herein, a literature study into the different strategies used to obtain self-assemblies of AuNPs using molecular linkers is presented. The use of nanospheres (AuNS) and nanorods (AuNRs) were mainly reviewed. Thereafter, two different nanobipyramids (AuBPs) were investigated for use in self-assemblies. The concentration of cetyltrimethylammonium bromide (CTAB), which coats the AuNP surface, was manipulated to study the stability of the AuNPs. A stable, meta-stable and non-stable region were identified for the nanoparticles. At low CTAB levels, the AuNPs preferentially assemble end-to-end. The addition of L-cysteine to stable AuNP dispersion induced end-to-end assembly, showing promise as a molecular linker for AuBPs. The addition of excess CTAB stabilized the assemblies over time. The kinetic behaviour of the two AuBPs differed, suggesting the effect of the AuNP shape on the self-assembly kinetics. This study provides a starting point for the development of a robust self-assembly strategy for anisotropic AuNPs by using L-cysteine as a molecular linker. / Den kolloidala självsammansättningen av ytplasmoniska guld nanopartiklar (AuNPs) är av intresse för att utnyttja de plasmoniska kopplingseffekterna som uppstår mellan nanopartiklar. De fördelaktiga egenskaperna hos anisotropa AuNP gör dem särskilt intressanta för självsammansättningar. En litteraturstudie har gjorts på de olika strategier som används för att erhålla självsammansättningar av AuNPs med hjälp av molekylära länkar. Användningen av nanosfärer (AuNS) och nanostavar (AuNRs) i självsammansättningar undesöktes huvudsakligen. Därefter undersöktes två olika nanobipyramider (AuBPs) för användning i självsammansättningar. Koncentrationen av cetyltrimetylammonium bromid (CTAB), som täcker AuNP-ytan, manipulerades för att undersöka AuNPs stabilitet. En stabil, meta-stabil och instabil region identifierades för nanopartiklarna. Vid låga CTAB-nivåer sammansätts AuNPs ände-mot-ände. Tillsatsen av L-cystein till stabila AuNP dispersioner inducerade sammansättningar ände-mot-ände, vilket visar L-cysteins potential som en molekylär länk för AuBPs. Tillsatsen av en stor mängd CTAB stabiliserade självsammansättningarna för en längre tid. Det kinetiska beteendet hos de två AuBPs skilde sig, vilket tyder på effekten av AuNP-formen på den självsammansättningskinetiken. Denna studie erbjuder en startpunkt för utvecklingen av en robust självsammansättningstrategi för anisotropa AuNPs genom att använda L-cystein som en molekylär länk.