Cell-derived extracellular vesicles can be used as a biomarker reservoir for glioblastoma tumor subtyping

Glioblastoma (GBM) is one of the most aggressive solid tumors for which treatment options and biomarkers are limited. Small extracellular vesicles (sEVs) produced by both GBM and stromal cells are central in the inter-cellular communication that is taking place in the tumor bulk. As tumor sEVs are accessible in biofluids, recent reports have suggested that sEVs contain valuable biomarkers for GBM patient diagnosis and follow-up. The aim of the current study was to describe the protein content of sEVs produced by different GBM cell lines and patient-derived stem cells. Our results reveal that the content of the sEVs mirrors the phenotypic signature of the respective GBM cells, leading to the description of potential informative sEV-associated biomarkers for GBM subtyping, such as CD44. Overall, these data could assist future GBM in vitro studies and provide insights for the development of new diagnostic and therapeutic methods as well as personalized treatment strategies

The Fatigue Threshold of Rubber and Its Characterization Using the Cutting Method

Below a limiting value of tearing energy called the intrinsic strength or fatigue threshold (T-0), cracks will not grow in rubber due to fatigue; hence, this material characteristic is important to understand from both fundamental and practical perspectives. We summarize key aspects of the fatigue threshold, including the Lake-Thomas molecular interpretation of T-0 in terms of fracture of polymer network chains in crosslinked elastomers. The various testing approaches for quantifying T-0 are also discussed, with a focus on the classic Lake-Yeoh cutting method which was recently revived by the introduction of a commercial testing instrument that applies this procedure, the Intrinsic Strength Analyser (ISA). A validation of the cutting method is also given by demonstrating that a 2-h test on the ISA yields a value of T-0 that is essentially identical to the T-0 from near-threshold fatigue crack growth (FCG) measurements that require 7.5 months of continuous testing. Compound formulation effects - polymer type, crosslink density, type and amount of reinforcing fillers, and addition of oils/plasticizers - are examined based on the limited published research in this area and our new results. At the end, some insights are offered into using the fatigue threshold to develop highly durable rubber products.Ministry of Education, Youth and Sports of the Czech Republic - DKRVO [RP/CPS/2020/004