MacKenzie, L. E. | Search bioRxiv

bioRxiv2023

Polyethylene terephthalate (PET) micro- and nanoplastic particles affect the mitochondrial efficiency of human brain vascular pericytes without inducing oxidative stress

The objective of this investigation was to evaluate the influence of micro- and nanoplastic particles composed of polyethylene terephthalate (PET), a significant contributor to plastic pollution, on human brain vascular pericytes. Specifically, we delved into their impact on mitochondrial functionality, oxidative stress, and the expression of genes associated with oxidative stress and ferroptosis. Our findings demonstrate that the exposure of a monoculture of human brain vascular pericytes to PET particles in vitro at a concentration of 50 ppm for a duration of 6 days did not elicit oxidative stress. Notably, we observed an augmentation in various aspects of mitochondrial respiration, including extracellular acidification, proton pump leakage, maximal respiration, spare respiratory capacity, and ATP production in pericytes subjected to PET particles. Furthermore, there were no statistically significant alterations in mitochondrial DNA copy number, or the expression of genes linked to oxidative stress and ferroptosis. These outcomes suggest that, at a concentration of 50 parts per million (ppm) and for 6 days exposure, PET particles do not induce oxidative stress in human brain vascular pericytes. Instead, they seem to incite a potential mitochondrial hormesis, also named mitohormesis, response, which seemingly enhances mitochondrial function. Further investigations are warranted to explore the stages of mitohormesis and the potential consequences of plastics on the integrity of the blood-brain barrier and intercellular interactions. This research contributes to our comprehension of the potential repercussions of nanoplastic pollution on human health and underscores the imperative need for ongoing examinations into the exposure to plastic particles. Graphical Abstract (created with BioRender.com) O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=140 SRC="FIGDIR/small/563735v1_ufig1.gif" ALT="Figure 1"> View larger version (59K): org.highwire.dtl.DTLVardef@2ea981org.highwire.dtl.DTLVardef@17a7619org.highwire.dtl.DTLVardef@df661eorg.highwire.dtl.DTLVardef@a9518f_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightO_LIFabrication of polyethylene terephthalate (PET) micro- and nanoplastics C_LIO_LIPET particles increase pericytes mitochondrial respiration functions C_LIO_LIPET particles increase pericytes extracellular acidification C_LIO_LIOxidative stress was not observed in pericytes subjected to PET particles C_LI

neuroscience↗

bioRxiv2018

Dye-free retinal angiography using blood-oxygenation modulation

Fluorescence angiography (FA) is widely used for studying and diagnosing abnormalities in the retinal blood circulation, but has associated risks of nausea, skin irritation, and even death. We describe a new non-invasive angiography technique: Blood Oxygenation Modulation Angiography, in which multispectral imaging of a transient perturbation in blood-oxygen saturation, yields angiography sequences similar to FA, including key features such as sequential filling of choroidal and retinal-vessels, which underpin assessment of circulation health. This is the first non-invasive angiography technique capable of visualizing these circulation features.

biophysics↗

bioRxiv2017

The molecular weight of NaYF4:RE photonic up-conversion nanoparticles

Upconversion nanoparticles (UCNPs) are utilized extensively for biomedical imaging, sensing, and therapeutic applications, yet the molecular weight of UCNPs has not previously been reported. We present a theory based upon the crystal structure of UCNPs to estimate the molecular weight of UCNPs: enabling insight into UCNP molecular weight for the first time. We estimate the theoretical molecular weight of various UCNPs reported in the literature, predicting that spherical NaYF4 UCNPs {small tilde} 10 nm in diameter will be {small tilde}1 MDa (i.e. 106 g/mol), whereas UCNPs {small tilde} 45 nm in diameter will be {small tilde}100 MDa (i.e. 108 g/mol). We also predict that hexagonal crystal phase UCNPs will be of greater molecular weight than cubic crystal phase UCNPs. Additionally we find that a Gaussian UCNP diameter distribution will correspond to a lognormal UCNP molecular weight distribution. Our approach could potentially be generalised to predict the molecular weight of other arbitrary crystalline nanoparticles: as such, we provide standalone graphic user interfaces to calculate the molecular weight both UCNPs and arbitrary crystalline nanoparticles. We expect knowledge of UCNP molecular weight to be of wide utility in biomedical applications where reporting UCNP quantity in absolute numbers or molarity will be beneficial for inter-study comparison and repeatability.

biophysics↗