Label-free discrimination of extracellular vesicles from large lipoproteins.

Extracellular vesicles (EVs) are increasingly gaining interest as biomarkers and therapeutics. Accurate sizing and quantification of EVs remain problematic, given their nanometre size range and small scattering cross-sections. This is compounded by the fact that common EV isolation methods result in co-isolation of particles with comparable features. Especially in blood plasma, similarly-sized lipoproteins outnumber EVs to a great extent. Recently, interferometric nanoparticle tracking analysis (iNTA) was introduced as a particle analysis method that enables determining the size and refractive index of nanoparticles with high sensitivity and precision. In this work, we apply iNTA to differentiate between EVs and lipoproteins, and compare its performance to conventional nanoparticle tracking analysis (NTA). We show that iNTA can accurately quantify EVs in artificial EV-lipoprotein mixtures and in plasma-derived EV samples of varying complexity. Conventional NTA could not report on EV numbers, as it was not able to distinguish EVs from lipoproteins. iNTA has the potential to become a new standard for label-free EV characterization in suspension.

Evaluation of a cross-linked versus non-cross-linked collagen matrix in full-thickness skin defects.

Autologous skin transplantation is the gold standard for treatment of full-thickness skin defects such as deep burn injuries, but has the disadvantages of limited donor sites and donor site morbidities. Alternative skin replacement products, such as xenografts and allografts, are not a permanent solution. Numerous manufactured skin substitutes already show promising approaches, but have limited efficacy. Therefore, wound dressings adaptable to the physiology of wound healing are still needed. In a randomized controlled in vivo study, a newly designed biocompatible collagen nonwoven matrix was compared to the Integra® bilayer dermal substitute and untreated controls in 48 full-thickness skin defects in a swine model. The take of all templates was complete, and all the tissue-engineered products accelerated dermal wound healing compared to the untreated controls, as identified by planimetric measurements. The higher collagen dose treatments and Integra®-covered wounds developed the thickest, cell-rich neoepidermal tissue in histological examination. The innovative biocompatible collagen matrix is flexibly applicable and modifiable, and offers potential as a carrier membrane for therapeutic supplemental products such as growth factors to further develop effective wound dressings.