Block copolymers, long chain molecules of two distinct chemical species joined covalently to one another, have long been known to form organized structures on the nanoscopic level. For example, if the two chains are the same length a lamellar structure results . In this work we show how this internal structure causes distinct deviation from 'normal' fluid behavior. We begin with the observation of block copolymer droplets with atomic force microscopy. We note the droplets form nearly conical shapes in stark contrast to the usual spherical cap. These droplets are found t o spread at an incredibly slow speed, and to have interesting instabilities in their wetting layer. We move on to studies of completely wet substrates (i.e. thin films) near the order-disorder transition of the material. Here we directly observe, with optical microscopy, a change in the fundamental spacing of the diblock's internal structure. This represents a superior method of measurement of the Flory-Huggins interaction parameter, which we verify in several ways. We also use the change in lamellar thickness to drive diffusion from one layer to another, and by similar measurements we can determine the kinetics of diffusion between the lamellar layers. In the last study we measure the lamellar edges on a gradient thickness sample with optical microscopy. In so doing we can directly observe surface induced ordering, and for the first time, can precisely resolve the near surface ordering dynamics. / Thesis / Doctor of Philosophy (PhD)

Extracellular vesicles (EVs) are lipid bilayer encapsulated nanoparticles which have emerged as an excellent source of biomarkers for multiple diseases, including cancer. However, they are highly heterogeneous in their molecular compositions which remains a major challenge hindering the utilization of their biomarker potential. A single-EV analysis is essential to both discovery and detect EVs that carry disease-specific signature. In this work, we designed plasmonic nanohole array for capturing single EVs and perform fluorescence detection of their membrane proteins by exploiting plasmonic amplification of the fluorescence signal. The design of the array was optimized using COMSOL Multiphysics-based simulation. Nanohole arrays with three different periodicities were fabricated on aluminum thin film on glass substrate. The substrates were then functionalized with three different methods for investigation of antibody-free capturing techniques, which are electrostatic interaction, hydrophobic interaction, and size-selective capturing. After surface functionalization with each of the techniques, genetically engineered EVs expressing mNeonGreen (mNG) were incubated and their capture efficiency were compared. The presence of single-EVs within plasmonic nanoholes was verified through both fluorescence analysis and atomic force microscopy (AFM). Fluorescence intensities of mNG-EVs recorded with the plasmonic chip with different periodicities showed intensity variations in agreement with the simulation results. Furthermore, the EVs were immunostained with R-phycoerythrin (R-PE) conjugated CD-9 to demonstrate the possibility of general and multimarker fluorescence detection. In a separate experiment, DOPC liposomes were synthesized and their deformability was analyzed by using AFM. The nanohole array provides a basis for a future platform of EV analyses, promising to capture the signature arising from low expressing proteins. / Extracellulära vesiklar (EV) är lipadmembranförsedda nanopartiklar som har dykt upp som en utmärkt källa till biomarkörer för flera sjukdomar, däribland cancer. De är dock mycket heterogena i sina molekylära sammansättningar, vilket skapar en stor utmaning och hindrar utnyttjandet av deras potential som biomarkörer. EV-analys på enpartikelnivå är nödvändig både för att upptäcka och detektera vesiklar som har en sjukdomsspecifik signatur. I detta arbete designade vi en plasmonisk uppsättning av nanohål för att fånga enstaka EVs och utföra fluorescensdetektion av deras membranproteiner genom att utnyttja plasmonisk amplifiering av fluorescenssignaler. Designen av uppsättningen optimerades med hjälp av COMSOL Multiphysics-baserad simulering. Nanohålsuppsättningar med tre olika periodiciteter tillverkades på tunn aluminiumfilm på glassubstrat. Substraten funktionaliserades sedan enligt tre olika metoder för undersökning av antikroppsfria bindningsmetoder. De tre metoderna är elektrostatisk interaktion, hydrofob interaktion och storleksselektiv bindning. Efter ytfunktionalisering med var och en av teknikerna inkuberades vesiklar genetiskt modifierade att uttrycka mNeonGreen (mNG) och deras bindningseffektivitet jämfördes. Närvaron av individuella EVs i plasmoniska nanohål bekräftades genom både fluorescensmikroskopi och atomkraftsmikroskopi (AFM). Fluorescensintensiteter för mNG-EVs registrerades med plasmonchipet med olika periodiciteter och visade intensitetsvariationer i överensstämmelse med simuleringsresultaten. Dessutom immunfärgades vesiklarna med R-fykoerytrin (R-PE) konjugerad CD-9 för att påvisa möjligheten till allmän och multimarkör fluorescensdetektion. I ett separat experiment syntetiserades DOPC-liposomer och deras deformerbarhet analyserades med AFM. Nanohåluppsättningen lägger grund för en framtida plattform för EV-analys, som lovar att fånga signaturen som uppstår från låguttryckande proteiner.

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Self-assembled lipid tubules are particularly attractive for inorganic synthesis and drug delivery because they have hollow cylindrical shapes and relatively rigid mechanical properties. In this thesis work, we have synthesized lipid tubules of 1,2-bis(tricosa-10,12-dinoyl)-sn-glycero-3-phosphocholine (DC8,9PC) by self-assembly and polymerization in solutions. We demonstrate for the first time that both uniform and modulated molecular tilt orderings exist in the tubule walls, which have been predicted by current theories, and therefore provide valuable supporting evidences for self-assembly mechanisms of chiral molecules. Two novel methods are developed for studying the axial and radial deformations of DC8,9PC lipid tubules. Mechanical properties of DC8,9PC tubules are systematically studied in terms of persistence length, bending rigidity, strain energy, axial and radial elastic moduli, and critical force for collapse. Mechanisms of recovery and surface stiffening are discussed. Due to the high aspect ratio of lipid tubules, the hierarchical assembly of lipid tubules into ordered arrays and desired architectures is critical in developing their applications. Two efficient methods for fabricating ordered arrays of lipid tubules on solid substrates have been developed. Ordered arrays of hybrid silica-lipid tubes are synthesized by tubule array-templated sol-gel reactions. Ordered arrays of optical anisotropic fibers with tunable shapes and refractive indexes are fabricated. This thesis work provides a paradigm for molecularly engineered structures.

Cell motility under physiological and pathological conditions including malignant progression of cancer and subsequent metastasis are founded on environmental confinements. During the last two decades, three-dimensional cell migration has been studied mostly by utilizing biomimetic extracellular matrix models. In the majority of these studies, the in vitro collagen scaffolds are usually assumed to be homogenous, as they consist commonly of one specific type of collagen, such as collagen type I, isolated from one species. These collagen matrices should resemble in vivo extracellular matrix scaffolds physiologically, however, mechanical phenotype and functional reliability have been addressed poorly due to certain limitations based on the assumption of homogeneity. How local variations of extracellular matrix structure impact matrix mechanics and cell migration is largely unknown. Here, we hypothesize that local inhomogeneities alter cell movement due to alterations in matrix mechanics, as they frequently occur in in vivo tissue scaffolds and were even changed in diseased tissues. To analyze the effect of structural inhomogeneities on cell migration, we used a mixture of rat tail and bovine dermal collagen type I as well as pure rat and pure bovine collagens at four different concentrations to assess three-dimensional scaffold inhomogeneities. Collagen type I from rat self-assembled to elongated fibrils, whereas bovine collagen tended to build node-shaped inhomogeneous scaffolds. We have shown that the elastic modulus determined with atomic force microscopy in combination with pore size analysis using confocal laser scanning microscopy revealed distinct inhomogeneities within collagen matrices. We hypothesized that elastic modulus and pore size govern cancer cell invasion in three-dimensional collagen matrices. In fact, invasiveness of three breast cancer cell types is altered due to matrix-type and concentration indicating that these two factors are crucial for cellular invasiveness. Our findings revealed that local matrix scaffold inhomogeneity is another crucial parameter to explain differences in cell migration, which not solely depended on pore size and stiffness of the collagen matrices. With these three distinct biophysical parameters, characterizing structure and mechanics of the studied collagen matrices, we were able to explain differences in the invasion behavior of the studied cancer cell lines in dependence of the used collagen model.

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