Ventilator-associated pneumonia (VAP) is a serious and costly clinical problem affecting pediatrics today. This devicerelated infection is thought to be directly linked to the colonization of the endotracheal tube (ETT) during long-term mechanical ventilation. Because of unspecific radiographic and clinical signs, VAP is especially difficult to diagnose in the pediatric population. Treatment with antibiotics is often ineffective, and VAP is associated with high morbidity, mortality, and medical costs. The use of nanomodified coatings on ETT may provide an effective strategy to prevent biofilm formation and ETT colonization. Nanoparticles such as selenium and iron oxide have been shown to penetrate into the biofilm reaching the protected cells antibiotics often miss. Moreover, nanoetching techniques can modify the topography of the ETT surface interfering with bacterial adhesion. This review seeks to examine the antimicrobial properties of both nanoparticles and nanomodified surfaces and to characterize their effectiveness at reducing bacterial colonization on ETT. (Pediatr Res 67: 500-504, 2010) N anotechnology is the control of matter at the atomic, molecular, and supramolecular scale. Nanomaterials, or materials (such as particles, fibers, tubes, grains, etc.) with at least one dimension in the range of 1-100 nm, can be metals, ceramics, polymers, or composites thereof. These materials exhibit unique properties because of their size and significantly greater surface areas, which can influence numerous properties including material conductivity, magnetic properties, surface energy, mechanical properties, catalytic properties, etc.An ongoing area of this research includes the interaction between synthetic nanoscale materials and living tissues. Micro-and nanoscale building blocks form the foundation for cells and tissues within the human body. It is thought that the difference in the activity of some cells on nanomodified surfaces is because of the ability of these materials to mimic the natural dimensions of constituents of biological tissues. Another important factor in this interaction is the unique surface energetics of nanomaterials because of their significantly greater surface areas compared with conventional, micron-structured materials. Such changes in surface energy undoubtedly influence initial protein interactions that are important for mediating bacteria and nonbacteria cell adhesion. Specifically, one of the first steps within the process of cell adhesion is the association of proteins adsorbed on implant surfaces to cell membrane receptors. The large surface to volume ratio characteristic of nanomaterials has been shown to affect this association to inhibit bacteria attachment and promote nonbacterial cell (such as osteoblasts, smooth muscle cells, endothelial cells, chondrocytes, etc.) adhesion (1). The type, concentration, conformation, and bioactivity of proteins adsorbed onto a material depend on its topographical (roughness), chemical, physical (charge and hydrophilicity), and mecha...

Microplastics and nanoplastics are emerging pollutants, widespread both in marine and in freshwater environments. Cyanobacteria are also ubiquitous in water and play a vital role in natural ecosystems, using photosynthesis to produce oxygen. Using photography, fluorescence microscopy and cryogenic and scanning electron microscopy (cryo-SEM, SEM) we investigated the physicochemical response of one of the most predominant seawater cyanobacteria (Synechococcus elongatus, PCC 7002) and freshwater cyanobacteria (S. elongatus Nageli PCC 7942) when exposed to 10 μm diameter polystyrene (microPS) and 100 nm diameter polystyrene (nanoPS) particles. Marine and freshwater cyanobacteria formed aggregates with the nanoPS, bound together by extracellular polymeric substances (EPS), and these aggregates sedimented. The aggregates were larger, and the sedimentation was more rapid for the marine system. Aggregate morphologies were qualitatively different for the microPS samples, with the bacteria linking up a small number of particles, all held together by EPS. There was no sedimentation in these samples. The cyanobacteria remained alive after exposure to the particles. The particle size-and salt concentration-dependent response of cyanobacteria to these anthropogenic stressors is an important factor to consider for a proper understanding of the fate of the particles as well as the bacteria.

Polyvinyl chloride (PVC) endotracheal tubes (ETTs) nanoetched with a fungal lipase have been shown to reduce bacterial growth and biofilm formation and could be an inexpensive solution to the complex problem of ventilator-associated pneumonia (VAP). Although bacterial growth and colonization on these nanoetched materials have been well characterized, little is known about the mechanism by which the fungal lipase degrades the PVC and, thus, alters its properties to minimize bacteria functions. This study used X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) to better describe the surface chemistry of both unetched and lipase nanoetched PVC ETT. ATR-FTIR analysis of the unetched and treated surfaces showed a similar presence of a plasticizer. This was confirmed by XPS analysis, which showed an increase of carbon and the presence of oxygen on both unetched and nanoetched surfaces. A quantitative comparison of the FTIR spectra revealed significant correlations (Pearson’s correlation, R =0.997 [ R 2 =0.994, P <0.001]) between the unetched and nanomodified PVC ETT spectra, demonstrating similar surface chemistry. This analysis showed no shifting or widening of the bands in the spectra and no significant changes in the intensity of the infrared peaks due to the degradation of the plasticizer by the fungal lipase. In contrast, results from this study did demonstrate significantly increased nanoscale surface features on the lipase etched compared to non-etched PVC ETTs. This led to a change in surface energetics, which altered ion adsorption to the ETTs. Thus, these results showed that PVC surfaces nanoetched with a 0.1% lipase solution for 48 hours have no significant change on surface chemistry but do significantly increase nanoscale surface roughness and alters ion adsorption, which suggests that the unique properties of these materials, including their previously reported ability to decrease bacterial adhesion and growth, are due to the changes in the degree of the nanoscale roughness, not changes in their surface chemistry.