Imaging of individual SWCNTs inside neural stem cells has been demonstrated using confocal scanning Raman microscopy. Hyperspectral Raman imaging allowed detection of nanomaterials applied to the cell in ultra-low doses in long-term studies.
Nanostructured biomaterials have been extensively explored in clinical imaging and in gene/drug delivery applications. However, limited studies have been performed that examine the influence that nanomaterials may have on cell behavior over long time scales at nonlethal concentrations. The study was designed to investigate whether carbon nanotubes are able to augment cell behavior at low concentrations. Single-walled carbon nanotubes were introduced to neural stem cells at different stages of differentiation at concentrations as low as 5 ng/mL. Results demonstrate that in this particular cell model, nanotube uptake is mediated by endocytosis.Differentiation is augmented, especially when nanotubes are introduced to cells in an actively dividing state. Significant increases in neuronal cell population were observed over the control specimens. While the mechanisms behind this observation are yet unknown, the study demonstrates that low concentrations of internalized nanomaterials can significantly alter the differentiation profile of a stem cell line.
Measuring the ratio is a classic experiment in the physics curriculum. We show that smartphones can reliably measure the magnetic field strengths involved. Moreover, phone cameras and the image-processing software Tracker can make determining the charge-to-mass ratio of the electron more accurate.
Tests that depend on changes in color are commonly used in biosensing. Here, we report on a colorimetric reader for such applications. The device is simple to construct and operate, making it ideal for research laboratories with limited resources or skilled personnel. It consists of a commercial multispectral sensor interfaced with a Raspberry Pi and a touchscreen. Unlike camera-based readers, this instrument requires no calibration of wavelengths by the user or extensive image processing to obtain results. We demonstrate its potential for colorimetric biosensing by applying it to the birefringent enzyme-linked immunosorbent assay. It was able to prevent certain false positives that the assay is susceptible to and lowered its limit of detection for glucose by an order of magnitude.
Delivery of materials, such as drug compounds or imaging agents for treatment or diagnosis of disease still presents a biomedical challenge. Nanotechnological advances have presented biomedicine with a number of agents that possess the appropriate size and chemistry to pass through the blood brain barrier. Functionalized carbon nanotubes are one such agent, which can potentially aid in drug and gene delivery to the central nervous system. In addition, carbon nanotubes have already been applied in several areas of nerve tissue engineering to probe and augment cell behavior, to label and track subcellular components, and to study the growth and organization of neural networks. Although the production of functionalized carbon nanotubes has escalated in recent years, knowledge of cellular changes associated with exposure to these materials remains unclear. Thus, it is crucial to develop an understanding of the effects and interactions that carbon nanotubes can induce in a living system. In this study, carbon nanotubes, wrapped with either GT20 DNA or yeast tRNA were introduced to neural stem cells during proliferation and differentiation, at doses determined to be non-lethal. At non-lethal doses, cell fate can be dramatically impacted by the carbon nanotube materials. Depending upon the mode of exposure, the differentiation dynamics are significantly altered, leading to at least a one-fold increase in the final percent of neurons in the total population. This increase in neuronal population is mathematically correlated to a change in the division symmetry of the dividing cells early in the differentiation process. In addition, the results demonstrate that the irregular patterns of cell fate are due to a variety of biophysical inputs stimulated by the carbon nanotubes, including, but not limited to, cytoskeletal perturbation, focal adhesion augmentation, and subcellular localization of the nanomaterials. Acknowledgment: NSF ECCS-1509786.
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