Publications by authors named "Adam Olsson"

Nucleation of sparingly soluble species, such as the inorganic salts of calcium, magnesium, and phosphorous, followed by their growth at solid-liquid interfaces has turned into a major concern in water-based industries. Increased resistance against heat, mass, and momentum transfer is the main drawback of the so-called scaling phenomenon. Although phosphorous-, nitrogen-, and sulfur-based antiscaling macromolecules offer adequate antiscaling performance, their potential negative environmental impacts render them less desirable.

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Total internal reflection fluorescence (TIRF) microscopy was used to investigate initial attachment and stability of wild-type, curli-deficient (ΔcsgA), flagella-deficient (ΔflhDC), and type-1 fimbriae-deficient (Δfim) mutant E. coli strains. Suspended bacteria were injected into a flow cell where they deposited on a silica coverslip, and images were acquired over a 2 min period.

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The quartz-crystal-microbalance-with-dissipation (QCM-D) has become a powerful tool for studying the bond viscoelasticity of biotic and abiotic colloidal particles adhering to substratum surfaces. A window-equipped QCM-D allows high-throughput analysis of the average bond viscoelasticity, measuring over 10 particles simultaneously in one single experiment. Other techniques require laborious analyses of individual particles.

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Surface immobilized bacteriophages (phages) are increasingly used as biorecognition elements on bacterial biosensors (e.g., on acoustical, electrical, or optical platforms).

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Quartz crystal microbalance with dissipation monitoring (QCM-D) was used to investigate initial adhesion and subsequent biofilm growth of wild-type Pseudomonas aeruginosa PAO1 and a pili-deficient (ΔpilA) mutant PAO1 strain. Clean, sterilized, silica-coated QCM-D crystals were pre-coated with lysogeny broth (LB), seeded with a PAO1 strain and allowed to grow for 20 h at 37 °C in fresh LB injected at 100 μL/min. QCM-D signals obtained for the wild-type PAO1 strain during the seeding period depict a large positive frequency shift that returns to baseline after ~20 min that is absent in the ΔpilA mutants, suggesting a dynamic pili-mediated attachment event for the wild-type PAO1 strain.

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Bacteriophage-functionalized bioactive surfaces are functional materials that can be used as antimicrobial surfaces in medical applications (e.g., indwelling medical devices or wound dressings) or as biosensors for bacterial capture and detection.

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In cold climate regions, microorganisms in upper layers of soil are subject to low temperatures and repeated freeze-thaw (FT) conditions during the winter. We studied the effects of cold temperature and FT cycles on the viability and survival strategies (namely motility and biofilm formation) of the common soil bacterium and model pathogen Bacillus subtilis. We also examined the effect of FT on the transport behavior of B.

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Despite cranberry being associated with the prevention of bacterial infections for over a century, our understanding of the bioavailability and mechanisms by which cranberry prevents infection is limited. This study investigates the interactions between cranberry proanthocyanidins (CPAC) and human serum proteins (albumin, α-1-acid glycoprotein, and fibrinogen) that may be encountered during CPAC metabolism following ingestion. To better understand how CPAC might interfere with bacterial infection, we also examined the interactions between CPAC and selected bacterial virulence factors; namely, lipopolysaccharide (LPS) and rhamnolipid.

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A quartz crystal microbalance with dissipation (QCM-D) monitoring can be an alternative tool to characterize nanoparticle size by virtue of its acoustic principle to sense adsorbed mass. In this study, sizes obtained by QCM-D for polymer-coated metallic nanoparticles and polydisperse polystyrene latex particle suspensions were compared with those obtained by transmission electron microscopy (TEM) and dynamic light scattering (DLS). We describe the obtained "QCM-D mass", which is weighted over surface area, by a general particle height distribution equation that can be used to determine the average particle diameter of a distribution of particles deposited on the QCM-D surface.

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A clear understanding of the factors controlling the deposition behavior of engineered nanoparticles (ENPs), such as quantum dots (QDs), is necessary for predicting their transport and fate in natural subsurface environments and in water filtration processes. A quartz crystal microbalance with dissipation monitoring (QCM-D) was used to study the effect of particle surface coatings and water chemistry on the deposition of commercial QDs onto Al2O3. Two carboxylated QDs (CdSe and CdTe) with different surface coatings were compared with two model nanoparticles: sulfate-functionalized (sPL) and carboxyl-modified (cPL) polystyrene latex.

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In a quartz crystal microbalance, particles adhering to a sensor crystal are perturbed around their equilibrium positions via thickness-shear vibrations at the crystal's fundamental frequency and overtones. The amount of adsorbed molecular mass is measured as a shift in resonance frequency. In inertial loading, frequency shifts are negative and proportional to the adsorbed mass, in contrast with "elastic loading", where particles adhere via small contact points.

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Staphylococcus aureus is known to cause biomaterial-associated infections of implants and devices once it has breached the skin and mucosal barriers. Adhesion is the initial step in the development of a biomaterial-associated infection, and strategies to prevent staphylococcal adhesion and thus biomaterial-associated infections require understanding of the adhesive bond. The aim of this study was to compare the adhesive bond stiffnesses of two S.

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It is commonly assumed that bacterial presence on a QCM sensor-surface is associated with a negative frequency shift according to conventional mass-loading theory. Here, we demonstrate that bacteria adhering to QCM sensor-surface may yield positive frequency shifts up to 1.9×10(-6) Hz per bacterium according to a coupled-oscillator theory.

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Studies in flow displacement systems have shown that the reversibility of bacterial adhesion decreases within seconds to minutes after initial contact of a bacterium with a substratum surface. Atomic force microscopy (AFM) has confirmed that the forces mediating bacterial adhesion increase over a similar time span. The interfacial rearrangements between adhering bacteria and substratum surfaces responsible for this bond maturation have never been studied.

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Triblock copolymers of polyethylene oxide (PEO) and polypropylene oxide (PPO), that is, PEOn-PPOm-PEOn, better known as Pluronic can adsorb to surfaces in either a pancake or a brushlike configuration. The brushlike configuration is advantageous in numerous applications, since it constitutes a surface repellent to proteins and microorganisms. The conformation of the adsorbed Pluronic layer depends on the hydrophobicity of the substratum surface, but the hydrophobicity threshold above which a brushlike conformation is adopted is unknown.

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Quartz crystal microbalance with dissipation (QCM-D) utilizes an oscillating quartz crystal to register adsorption of rigid masses through a decrease in its resonance frequency f. In addition, QCM-D has the ability to measure the dissipative nature of nonrigid masses adhering to the crystal surface in the form of oscillation amplitude decay time. Although QCM has been applied to register bacterial adhesion to the crystal surface, full interpretation of the frequency change and dissipation signal has hitherto been impossible due to the complex interactions within the distance of 250 nm between the substratum and the bacterial cell surface.

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The interaction between cells and biomaterials has been mimicked using nylon microparticles as pseudo-cells and PLMA and PIBMA as biomaterial model acrylate polymers. The shift of fundamental resonance frequencies was negative for both polymers, indicating mass-coupling to the sensor surface. The shifts of the 3rd, 5th and 7th overtone frequencies were initially positive for both polymers, indicating a particle slip or wobbling on the surface.

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