Noninvasive Detection, Tracking, and Characterization of Aerogel Implants using Diagnostic Ultrasound

Medical implants are routinely tracked and monitored using different techniques, such as MRI, X‐ray, and ultrasound. Due to the need for ionizing radiation, the two former methods pose a significant risk to tissue. Ultrasound imaging, however, is non‐invasive and presents no known risk to human tissue. Aerogels are an emerging material with great potential in biomedical implants. While qualitative observation of ultrasound images by experts can already provide a lot of infor-mation about the implants and the surrounding structures, this paper describes the development and study of two simple B‐Mode image analysis techniques based on attenuation measurements and echogenicity comparisons, which can further enhance the study of the biological tissues and implants, especially of different types of biocompatible aerogels

Direct ink writing of ultra-high temperature ceramics

Please click Additional Files below to see the full abstract

Entwicklung von Nanopartikel modifizierten Epoxiden als Matrix für Faserverbundwerkstoffe mit optimierten Eingenschaften

Diese Arbeit beschäftigt sich mit der Herstellung von Nano-Carbon gefüllten Epoxy-Kompositen. Als Füllmaterialien wurden verschiedene Arten von Graphen und Kohlenstoff-Nanoröhrchen verwendet und ihr Einfluss auf die mechanischen, elektrischen und thermischen Eigenschaften des Nanokompositen untersucht. An einem ternär gefüllten Epoxy-Komposit wurde das Zusammenspiel zweier verschiedener Füller-Arten beispielhaft aufgezeigt. Das Hauptaugenmerk dieser Arbeit liegt auf der Entwicklung einer mechanistischen Vorstellung, die sowohl den beobachtbaren Verstärkungseffekts der Graphen Füller auf die Epoxid Matrix als auch ihren Einfluss auf das Versagen erklärt. Das Hauptaugenmerk dieser Arbeit liegt auf der Evaluation der Versagensmechanismen und des Verstärkungseffektes von Graphen gefüllten Epoxid Systemen. Das Hauptaugenmerk dieser Arbeit liegt der Entwicklung des Verständnisses der Versagensmechanismen und des Verstärkungseffektes von Graphen gefüllten Epoxid Systemen.In this work, different types of graphene filler were dispersed in epoxy matrix, to prepare a graphene based epoxy nano-composite and compared with carbon nanotube reinforced epoxy system. The effect of filler addition on mechanical, electrical and thermal properties of the nano-composites was studied. The interaction between the fillers was studied by intermixing different fillers by means of bi-filler epoxy composites. The main object of the current study is to understand the failure mechanisms and toughening effects of graphene based fillers in epoxy composites

PC-12 cells adhesion and differentiation on carbon aerogel scaffolds

Electrically conducting substrates have shown much promise as neuronal scaffolds and in other biologic and biomedical applications where a smart and electrically interactive material is needed. Most materials that are inherently conducting are not suitable for biomedical applications and lack biocompatibility or biostability. On the other hand, biologically stable and compatible materials must first be manipulated, modified, and treated in order to impart the necessary electrical conductivity to the material. Here, the authors have investigated the response of PC-12 cells to two types of conducting carbon-based aerogels with different surface roughness. Results show that carbon-based aerogels support cell adhesion, proliferation, and neurite extension. The effects of surface roughness have also been investigated

Enhanced neurite outgrowth on electrically conductive carbon aerogel substrates in the presence of an external electric field

Previous works from our laboratory have firmly established that aerogels are a suitable substrate to elicit accelerated neurite extension. On non-conducting aerogels, in the presence of an externally-applied DC bias, neurons extended neurites which were preferentially aligned towards the anode. In this investigation, we sought to determine whether electrically-conductive carbon aerogels elicited a more robust alignment of neurites toward the anode than non-conductive aerogels due to the capacity of conductive aerogels to sustain a current, thereby providing a direct interface between neurons and the external electrical stimulus. To determine if this was the case, we plated PC12 neuronal cells on electrically conductive carbon aerolges derived from acetic acid-catalized resorcinol formaldehyde aerogels (ARF-CA) and subjected them to an external electric field. The voltages applied at the electrodes of the custom-built electro-stimulation chamber were 0 V, 15 V, and 30 V. For each voltage, the directionality and length of the neurites extended by PC12 cells were determined and compared to those observed when PC12 cells were plated on non-conductive aerogels subjected to the same voltage. The results show that the directionality of neurite extension was similar between conductive and non-conductive aerogels. A higher neurite length difference was observed on conductive aerogels with increasing voltage, 43% and 106% for 0-15 V and 0-30 V respectively, compared to non-conductive aerogels, 12% and 20%. These findings indicate that conductive carbon aerogels have a greater potential as scaffolds for nerve regeneration than non-conductive ones

Acoustofluidic Micromixing Enabled Hybrid Integrated Colorimetric Sensing, for Rapid Point-of-Care Measurement of Salivary Potassium

The integration of microfluidics with advanced biosensor technologies offers tremendous advantages such as smaller sample volume requirement and precise handling of samples and reagents, for developing affordable point-of-care testing methodologies that could be used in hospitals for monitoring patients. However, the success and popularity of point-of-care diagnosis lies with the generation of instantaneous and reliable results through in situ tests conducted in a painless, non-invasive manner. This work presents the development of a simple, hybrid integrated optical microfluidic biosensor for rapid detection of analytes in test samples. The proposed biosensor works on the principle of colorimetric optical absorption, wherein samples mixed with suitable chromogenic substrates induce a color change dependent upon the analyte concentration that could then be detected by the absorbance of light in its path length. This optical detection scheme has been hybrid integrated with an acoustofluidic micromixing unit to enable uniform mixing of fluids within the device. As a proof-of-concept, we have demonstrated the real-time application of our biosensor format for the detection of potassium in whole saliva samples. The results show that our lab-on-a-chip technology could provide a useful strategy in biomedical diagnoses for rapid analyte detection towards clinical point-of-care testing applications

PC-12 cells adhesion and differentiation on carbon aerogel scaffolds

Electrically conducting substrates have shown much promise as neuronal scaffolds and in other biologic and biomedical applications where a smart and electrically interactive material is needed. Most materials that are inherently conducting are not suitable for biomedical applications and lack biocompatibility or biostability. On the other hand, biologically stable and compatible materials must first be manipulated, modified, and treated in order to impart the necessary electrical conductivity to the material. Here, the authors have investigated the response of PC-12 cells to two types of conducting carbon-based aerogels with different surface roughness. Results show that carbon-based aerogels support cell adhesion, proliferation, and neurite extension. The effects of surface roughness have also been investigated

Noninvasive Detection, Tracking, and Characterization of Aerogel Implants Using Diagnostic Ultrasound

Medical implants are routinely tracked and monitored using different techniques, such as MRI, X‐ray, and ultrasound. Due to the need for ionizing radiation, the two former methods pose a significant risk to tissue. Ultrasound imaging, however, is non‐invasive and presents no known risk to human tissue. Aerogels are an emerging material with great potential in biomedical implants. While qualitative observation of ultrasound images by experts can already provide a lot of infor-mation about the implants and the surrounding structures, this paper describes the development and study of two simple B‐Mode image analysis techniques based on attenuation measurements and echogenicity comparisons, which can further enhance the study of the biological tissues and implants, especially of different types of biocompatible aerogels

Noninvasive Detection, Tracking, and Characterization of Aerogel Implants using Diagnostic Ultrasound

Medical implants are routinely tracked and monitored using different techniques, such as MRI, X‐ray, and ultrasound. Due to the need for ionizing radiation, the two former methods pose a significant risk to tissue. Ultrasound imaging, however, is non‐invasive and presents no known risk to human tissue. Aerogels are an emerging material with great potential in biomedical implants. While qualitative observation of ultrasound images by experts can already provide a lot of infor-mation about the implants and the surrounding structures, this paper describes the development and study of two simple B‐Mode image analysis techniques based on attenuation measurements and echogenicity comparisons, which can further enhance the study of the biological tissues and implants, especially of different types of biocompatible aerogels