Introduction to Nanotechnology

Synthesis and Characterization of Silica, Silver-Silica, and Zinc Oxide-Silica Nanoparticles for Evaluation of Blood Biochemistry, Oxidative Stress, and Hepatotoxicity in Albino Rats

Evaluation of nanoparticles (NPs) for biomedical applications has received a lot of attention for detailed study on pharmacokinetics prior to clinical application. In this study, pure C-SiO₂ (crystalline silica) NPs and SiO₂ nanocomposites with silver (Ag) and zinc oxide (ZnO) were prepared by utilizing different synthesis routes such as sol-gel and co-precipitation techniques. The prepared NPs showed highly crystalline nature as confirmed by X-ray diffraction analysis where average crystallite sizes of 35, 16, and 57 nm for C-SiO₂, Ag-SiO₂, and ZnO-SiO₂ NPs, respectively, were calculated. Fourier transform infrared analysis confirmed the presence of functional groups related to the chemicals and procedures used for sample preparation. Due to agglomeration of the prepared NPs, the scanning electron microscope images showed large particle sizes when compared to their crystalline sizes. The optical properties of the prepared NPs such as absorption were obtained with UV-Vis spectroscopy. For in vivo biological evaluation, albino rats, both male and female, kept in different groups were exposed to NPs with 500 μg/kg dose. Hematological, serum biochemistry, histo-architecture, oxidative stress biomarkers, and antioxidant parameters in liver tissues along with various biomarkers for the evaluation of erythrocytes were estimated. The results on hemato-biochemistry, histopathological ailments, and oxidative stress parameters exhibited 95% alteration in the liver and erythrocytes of C-SiO₂ NPs-treated rats while 75 and 60% alteration in the liver tissues of rats due to exposure to Ag-SiO₂ and ZnO-SiO₂ NPs, respectively, when compared with the albino rats of the control (untreated) group. Therefore, the current study showed that the prepared NPs had adverse effects on the liver and erythrocytes causing hepatotoxicity in the albino rats in respective order C-SiO₂ > Ag SiO₂ > ZnO-SiO₂. As the C-SiO₂ NPs appeared to be the most toxic, it has been concluded that coating SiO₂ on Ag and ZnO reduced their toxicological impact on albino rats. Consequently, it is suggested that Ag-SiO₂ and ZnO-SiO₂ NPs are more biocompatible than C-SiO₂ NPs.

Carbon Nanotubes and Chronic Granulomatous Disease

Use of nanomaterials in manufactured consumer products is a rapidly expanding industry and potential toxicities are just beginning to be explored. Combustion-generated multiwall carbon nanotubes (MWCNT) or nanoparticles are ubiquitous in non-manufacturing environments and detectable in vapors from diesel fuel, methane, propane, and natural gas. In experimental animal models, carbon nanotubes have been shown to induce granulomas or other inflammatory changes. Evidence suggesting potential involvement of carbon nanomaterials in human granulomatous disease, has been gathered from analyses of dusts generated in the World Trade Center disaster combined with epidemiological data showing a subsequent increase in granulomatous disease of first responders. In this review we will discuss evidence for similarities in the pathophysiology of carbon nanotube-induced pulmonary disease in experimental animals with that of the human granulomatous disease, sarcoidosis.

Technology for mobility in SCI 10 years from now

OBJECTIVES

To identify technological advances and that are likely to have a great impact on the quality of life and participation in individuals with spinal cord injury (SCI).

METHODS

In this paper we use the International Classification of Function to frame a discussion on how technology is likely to impact SCI in 10 years. In addition, we discuss the implication of technological advances on future research.

RESULTS/CONCLUSION

Although technology advances are exciting, a large challenge for the research community will be how to effectively apply and deploy this technology. Advances occurring in the next 10 years that reduce cost of technology may be more important to the population with SCI than brand new technologies. Social context is everything. As a research community we must advocate for better systems of care. Advocating now for better care will lead to a world in 2020 that is ready to adopt new technologies that are truly transformative.

Submicron-textured biomaterial surface reduces staphylococcal bacterial adhesion and biofilm formation

Staphylococci are among the most important pathogens causing bloodstream infections associated with implanted medical devices. Control of bacterial adhesion to material surfaces is important for prevention of biofilm formation and biomaterial-associated infections. In this study, we hypothesized that submicron (staphylococcal bacterial dimension) surface textures may reduce the bacterial adhesion via a decrease in surface area that bacteria can contact, and subsequently inhibit biofilm formation. Poly(urethane urea) films were textured with two different sizes of submicron pillars via a two-stage replication process. Adhesion of two bacterial strains (Staphylococcus epidermidis RP62A and S. aureus Newman) was assessed over a shear stress range of 0-13.2 dyn cm(-2) using a rotating disk system in physiological buffer solutions. Significant decreases in bacterial adhesion were observed on textured surfaces for both strains compared with smooth controls. Biofilm formation was further tested on surfaces incubated in solution for either 2 or 5 days and it was found that biofilm formation was dramatically inhibited on textured surfaces. The results of the approaches used in this work demonstrate that patterned surface texturing of biomaterials provides an effective means to reduce staphylococcal adhesion and biofilm formation on biomaterial surfaces, and thus to prevent biomaterial-associated infections.

Future directions for spinal cord injury research: recent developments and model systems contributions

The authors look forward and discuss future directions in spinal cord injury (SCI) from a perspective of biomedical, psychosocial and technologic research. This discussion is based both on recent developments from various fields of knowledge and, more specifically, on SCI Model Systems' research contributions to medical rehabilitation. Biomedical research, as described here, includes (1) the process of moving from the "bench to bedside" and harnessing knowledge from basic science to produce new clinical treatment options for SCI during the life span; (2) the rapid proliferation of clinical trials aimed at neurologic recovery; (3) the growth of new technologies to restore and improve function; and (4) the challenges of developing relevant outcome measures to evaluate efficacy and effectiveness of interventions. Recent progress in psychosocial research has contributed significantly to understanding of the many factors associated with disability during the life course, the importance of quality of life issues, and the value of activity, participation, and the environment in promoting successful rehabilitation outcomes following SCI. Technology and bioengineering advances are discussed in relation to access to high-quality technology; restoration and replacement of movement; and technology to enhance rehabilitation outcomes.

Electronic anabolic steroid recognition with carbon nanotube field-effect transistors

A proof of concept of the electronic detection of two anabolic steroids, stanozolol (Stz) and methylboldenone (MB), was carried out using two specific antibodies and arrays of carbon nanotube field-effect transistors (CNTFETs). Antibodies specific for Stz and MB were prepared and immobilized on the carbon nanotubes (CNTs) using two different approaches: direct noncovalent bonding of antibodies to the devices and bonding the antibodies covalently to a polymer previously attached to the CNTFETs. The results indicated that CNTFETs bonded to specific antibodies covalently or noncovalently are able to detect the presence of steroids. Statistically significant changes in the threshold voltage and drain current were registered in the transistors, allowing the steroids to be recognized. On the other hand, it was determined that the specific antibodies do not detect other steroids other than Stz and MB, such as nandrolone (ND) because, in this case, statistically significant changes in the transistors were not detected. The polymer prevents the aggregation of antibodies on the electrodes and decreases the transistor hysteresis. Nevertheless, it is not able to avoid the nonspecific adsorption of streptavidin, meaning that nonspecific adsorption on CNTs remains a problem and that this methodology is only useful for purified samples. Regarding the detection mechanism, in addition to charge transfer, Schottky barrier, SB, modification, and scattering potential reported by other authors, an electron/hole trapping mechanism leading to hysteresis modification has been determined. The presence of polymer seems to hinder the modulation of the electrode-CNT contact.

Design and adsorption of modular engineered proteins to prepare customized, neuron-compatible coatings

Neural prosthetic implants are currently being developed for the treatment and study of both peripheral and central nervous system disorders. Effective integration of these devices upon implantation is a critical hurdle to achieving function. As a result, much attention has been directed towards the development of biocompatible coatings that prolong their in vivo lifespan. In this work, we present a novel approach to fabricate such coatings, which specifically involves the use of surface-adsorbed, nanoscale-designed protein polymers to prepare reproducible, customized surfaces. A nanoscale modular design strategy was employed to synthesize six engineered, recombinant proteins intended to mimic aspects of the extracellular matrix proteins fibronectin, laminin, and elastin as well as the cell-cell adhesive protein neural cell adhesion molecule. Physical adsorption isotherms were experimentally determined for these engineered proteins, allowing for direct calculation of the available ligand density present on coated surfaces. As confirmation that ligand density in these engineered systems impacts neuronal cell behavior, we demonstrate that increasing the density of fibronectin-derived RGD ligands on coated surfaces while maintaining uniform protein surface coverage results in enhanced neurite extension of PC-12 cells. Therefore, this engineered protein adsorption approach allows for the facile preparation of tunable, quantifiable, and reproducible surfaces for in vitro studies of cell-ligand interactions and for potential application as coatings on neural implants.