Ventilator associated pneumonia (VAP) is a serious and costly clinical problem. Specifically, receiving mechanical ventilation over 24 hours increases the risk of VAP and is associated with high morbidity, mortality and medical costs. Cost effective endotracheal tubes (ETTs) that are resistant to bacterial infection would help to prevent this problem. The objective of this study was to determine differences in bacterial growth on nanomodified and unmodified ETTs under dynamic airway conditions, a bench top model based upon the general design of Hartmann et al. (1999) was constructed to test of the effectiveness of nanomodified ETTs under the airflow conditions present in the airway. Twenty-four hour studies performed in a dynamic flow chamber showed a marked difference in the biofilm formation on different areas of unmodified tubes. Areas where tubes were curved, such as at the entrance to the mouth and the connection between the oropharynx and the larynx, seemed to collect the largest amount of biofilm. On the nanomodified tubes biofilm formation was markedly different occurring on smaller pieces.

The biofilm formation on ETTs in the airflow system after 24 hours showed a large difference depending upon where tubes were oriented within the apparatus. This illustrates the importance of dynamic flow on biofilm formation in pediatric ETTs. It is of particular interest that increased biofilm density on both unmodified and nanomodified tubes appeared to occur at curves in the tube where changes in flow pattern occured. This emphasizes the need for more accurate models of airflow within pediatric ETTs, suggesting that not only does flow affect pressure gradients along the tube, but in fact, determines the composition of the film itself. More testing is needed to determine the effects of biofilm formation on the efficiency of ETT under airflow, however this study provides significant evidence for nanomodification alone (without the use of antibiotics) to decrease bacteria function.

The surface of Ti-based bulk metallic glass (BMG) was irradiated by the femto-second laser and microgrooves were formed on the surface. The titanate nanomesh layers were fabricated on the micro-grooved BMG surface by hydrothermal-electrochemical (H-E) treatment changing the conditions of the concentration of electrolyte solution (0 and 5 M) and applying current density (0-200 mA/cm2). The bone-inducing capacity of the samples with different H-E treatment was confirmed by soaking them in a simulated body fluid for 12 days. The H-E treatment in higher concentration 5 M NaOH aq. and applying higher current density above 0.5 mA/cm2 exhibited excellent bioactivity inducing large hydroxyapatite crystallites.

In the electrospinning process, fibers ranging from 50 nm to 1000 nm or greater can be produced by applying an electric potential to a polymeric solution [1, 2]. Our group has studied the fabrication of electro-spun Poly-caprolactone (PCL) nanofiber consisting of a range of fiber diameter (nm-um) and pore sizes. PCL is a biocompatible, FDA approved and biodegradable [3, 4] polymer. As a solvent we have used 2,2,2-trifluoroethanol (TFE) for its biocompatibility, conductivity and high dielectric constant. The electrospinning technique consists of a simple setup with a number of variables working in a complex and unpredictable way. The variables affecting fiber diameter are polymer concentration in the solution, flow rate, applied voltage, tip to collector distance, diameter of the needle/capillary, polymer/solvent dielectric constant etc. In our study we have found that concentration of the solution and molecular weight of the polymer are the most important parameters for forming the nanofibers and viscosity is important for the fiber diameter. To optimize so many variables to control the fiber diameter, we have used the factorial design method. The study is important for the fabrication of biomimetic scaffold for vascular implant and tissue engineering application.

Composite Organic-Inorganic Nanoparticles (COINs) are a novel type of surface-enhanced Raman (SER) scattering nanoparticle formed by aggregating inorganic silver particles in the presence of a chosen organic molecule with a distinct Raman fingerprint. Binding between antibody-functionalized COINs and cells is detected primarily using Raman spectroscopy, which measures spectral shifts of the excitation light due to inelastic scattering. It has been suggested that the amount of antibody-conjugated COINs binding on cells will vary according to the antigen-expression levels in cells and will lead to changes in measured SERS intensities. COINs functionalized with antibodies CD54 and CD8 were conjugated to U937 and SupT1 cancer cells and investigated in this study. SERS intensity measurements were obtained from each of the four sample variants and normalized against control samples comprising non-antibody-functionalized COINs with cells. The amount of COINs binding on cells was determined using scanning electron microscopy (SEM) and correlated with the SER spectroscopy intensity. Although we found a positive correlation between the number of COINs binding to cells and their respective SERS intensity, this relationship is not one-to-one, nor does it appear to be linear. We demonstrated that SEM imaging and SER spectroscopy can complement each other to provide information about COINs binding onto cancer cells.

Nanotechnology, or the use of materials with one dimension less than 100nm, offers the ability to change particle reactivity by simply changing their size. This novel property of nanomaterials is used to create more effective medical treatments for cancer, tissue engineering and regenerative medicine, but the influence of nanoparticle size on environmental toxicity has not been thoroughly addressed to date. This study examines the influence of the size of silver particles on drosophila egg development by exposing their eggs to particle concentrations ranging from 10ppm-100 ppm of silver. Size, chemistry and agglomeration of the silver particles are evaluated using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and dynamic light scattering (DLS). This analysis confirmes individual silver particle size in the ranges of 20-30nm, 100nm and 500-1,200 nm with similar chemistry. DLS and TEM data also indicates agglomeration in water; with the TEM images showing individual particles in the correct size range, but the DLS z-average sizes of the silver nanoparticle are 782 ± 379 nm for the 20-30nm silver nanoparticles, 693 ± 114 nm for the 100nm silver nanoparticles and 508 ± 32 nm for the 500-1,200nm silver particles. Most importantly, here we show significantly more drosophila egg toxicity when exposed to larger, non-nanometer, silver particles. Upon exposure to silver nanoparticles sized 20-30nm, drosophila eggs do not exhibit a statistically significant (p<0.05) decrease in their likelihood to pupate, but eggs exposed to larger silver particles (500-1,200nm) are 91% (±18%) less likely to pupate. Exposure to silver nanoparticles reduces the percentage of pupa able to emerge as adults. At 10ppm of silver particle exposure, only 57% (± 48) of the pupa exposed to 20-30nm silver particles become adults whereas 89% (±25) of the control group becoem adults and 94%(±52) and 91%(±19) of the 500-1,200nm and 100nm group, respectively, reached adulthood. In this manner, this paper provides evidence that nanoscale silver particles (<100nm) are less toxic to drosophila eggs than conventional (>100nm) sized silver particles.