In this study, we describe the development of surface-modified chitosan substrates to examine topographically related Neuro-2a cell behaviors. Different functional groups can be modified on chitosan surfaces to probe Neuro-2a cell morphology. To prepare chitosan substrates with micro/nano-scaled features, we demonstrated an easy-to-handle method that combined photolithography, inductively coupled plasma reactive ion etching, Ag nanoparticle-assisted etching, and solution casting. The results show that Neuro-2a cells preferred to adhere to a flat chitosan surface rather than a nanotextured chitosan surface as evidenced by greater immobilization and differentiation, suggesting that surface topography is crucial for neural patterning. In addition, we developed chitosan substrates with different geometric patterns and flat region depth; this allowed us to re-arrange or re-pattern Neuro-2a cell colonies at desired locations. We found that a polarity-induced micropattern provided the most suitable surface pattern for promoting neural network formation on a chitosan substrate. The cellular polarity of single Neuro-2a cell spreading correlated to a diamond-like geometry and neurite outgrowth was induced from the corners toward the grooves of the structures. This study provide greater insight into neurobiology, including neurotransmitter screening, electrophysiological stimulation platforms, and biomedical engineering.
The roughness of a multiphase interface and the associated topography between silicone oil and an alcohol-based fluid were measured with an atomic force microscope (AFM) and compared with the results of calculations based upon a capillary-wave model. According to this theory, the interfacial roughness of a liquid-liquid interface depends on the density, interfacial tension, and temperature of the liquids. Test samples prepared with both silicone oil and an alcohol-based fluid at various volumetric ratios and controlled temperatures were carefully measured. The experimental results indicate that the interfacial roughness measured with an AFM was consistent with the capillary-wave model. The measured interfacial roughness is influenced mainly by the interfacial tension between the liquids and the temperature-driven Brownian motion of the molecules. Three-dimensional topographical pictures of the interfaces were constructed and archived digitally for subsequent investigation. By employing the outlined method, we examined the microscopic details of interfacial properties, with prospective applications in biochemical and biophysical research.
Single-stranded DNA (ssDNA) with repetitive sequence was demonstrated to be a versatile nanotemplate for introducing biological activity in a self-assembled manner. Re-functionalization and rejuvenation of the ssDNA nanotemplate were achieved under mild biological conditions without using high temperature and strong alkaline treatment to denature DNA.
Urinary tract infections (UTI), one of the most common bacterial infections, annually affect 150 million people worldwide. Infants and the elderly are likely to have missed or delayed diagnosis of UTI due to difficulty clearly describing their symptoms. A rapid screening method for UTI is a critical and urgent need for these populations. The aim of our study is to develop a diaper-based testing device to assay urine biomarkers including pH, leukocyte, and nitrite level. This all-in-one device assists in urine collection and testing using a colorimetric approach to provide easily read visual results on the outside surface of a test strip-integrated diaper. In this study, we tested samples from 46 patients using testing strips and examined the results from 7 patients recruited to validate the strip-integrated diaper. In conclusion, this new diaper-based testing device is easy to use, rapid, and inexpensive, all of which imbue it with tremendous potential for development into a commercially viable UTI screening system.
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