Investigating cell killers: Advanced system for size-dependent cytotoxicity analysis of silica
Scientists present a new analysis technique for size-separated evaluation of silica nanoparticle toxicity toward human hepatoma cells
2024-02-29
(Press-News.org)
Metal nanomaterials have become an indispensable part of industrial and medical fields due to their unique and versatile properties. Their size, which imparts them with the desired physiochemical properties, is also the reason for environmental and health concerns. The nano-sized particles in nanomaterials have shown high reactivity towards biomolecules and often even toxicity towards biological cells.
Scientists have attributed this behavior of metal nanoparticles in interaction with biomolecules to phenomena like inflammation or oxidative stress. However, to ensure the safe usage of metal nanoparticles, there is a need to explore molecular mechanisms responsible for the toxicity and understand how the uptake of nanoparticles by cells varies based on their shape, size, morphology, and other aspects.
To shed light on this issue, Assistant Professor Yu-ki Tanaka and Prof. Yasumitsu Ogra, both from the Graduate School of Pharmaceutical Sciences at Chiba University, have now estimated the cellular intake of silica nanoparticles (SiNPs) based on their sizes. In their recent breakthrough published in Archives of Toxicology on January 14, 2024, the researchers developed an AF4-ICP-MS (asymmetric flow field flow fractionation with inductively coupled plasma mass spectrometry) system, which separated SiNPs of five different sizes (10, 30, 50, 70, and 100 nm) and enabled quantitative assessment of cytotoxicity of SiNPs in HepG2 cells.
“SiNPs have gained momentum in various fields such as drug delivery, biomedical imaging, catalysts as well as environmental remediation for removing contaminants from water and soil. However, there is also a significant concern about its environmental toxicity and potential impact on living organisms,” says Dr. Tanaka when asked about the motivation behind this study. “So, to find a remedy to the trade-off between industrial availability and toxicity, we decided to develop a technique to understand the potential adverse effects of SiNPs by combining quantitative data on cellular uptake and toxicological responses.”
Size analysis techniques like electron microscopy and laser-based dynamic light scattering failed to observe nanoparticle specimens in deep layers and elucidate the chemical compositions of the nanoparticles. To counter these issues, the team adopted the new AF4-ICP-MS size analysis technique, which not only overcame those issues but also detected nanoparticles of size as low as 10 nm. This wouldn’t have been possible with conventional ICP-MS methods.
The team used the AF4-based method to evaluate the cellular uptake of SiNPs in lab-cultured human hepatoma HepG2 cells. The measurements showed that approximately 17% of the SiNPs exposed to the HepG2 cells were absorbed. The transmission electron microscopy (TEM) carried out by the team observed the presence of SiNP aggregates within the cells, indicating the ability of small nanoparticles to settle down in the culture medium and enter the cells easily.
“We found that the smaller SiNPs exhibited higher toxicity towards the HepG2 cells than the larger ones, but the AF4-ICP-MS analysis found no significant size-dependent difference in the particle volume absorbed by the cells,” remarks Dr. Tanaka, highlighting the outcomes of the toxicity experiments. These results suggested that the elevated cytotoxic behavior of the small SiNPs was rooted in the large surface area relative to particle volume when compared to the larger ones.
The researchers also investigated the chemical mechanisms associated with cytotoxicity. The data indicated that cell necrosis was partly linked to oxidative stress caused by the production of reactive oxygen species (ROS). Additionally, interactions of the silanol groups on the SiNP surface and phospholipids in the cell membrane were responsible for the associated cell damage.
Overall, the results present the new AF4-ICP-MS technique as a powerful tool for quantitatively determining cytotoxicity induced by metal nanoparticles of varying sizes. The insights from this study also provide a solid groundwork for future studies looking into the evaluation of nanoparticle exposure risks and their potential burden on human bodies. “Our study aim was to come up with a facile analysis technique that would aid in the mission of minimizing potential health damage from nanoparticles. We are hopeful that the toxicological information provided by our study will help establish criteria for the proper utilization and regulation of nanoparticles in industries, the medical field, and even in daily use items containing nanoparticles,” concludes Dr. Tanaka.
About Assistant Professor Yu-ki Tanaka
Yu-ki Tanaka is an Assistant Professor at the Graduate School of Pharmaceutical Sciences at Chiba University. He belongs to the Laboratory of Toxicology and Environmental Health supervised by Prof. Yasumitsu Ogra. His research interests include single-cell analysis, single-particle analysis, stable isotope metallomics, metalloid toxicity, and metabolism. He has published around 30 research papers on these topics, which have received around 250 citations.
END
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
2024-02-29
People at risk of Alzheimer’s disease have impaired spatial navigation prior to problems with other cognitive functions, including memory, finds a new study led by UCL researchers.
The research, published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, used virtual reality to test the spatial navigation of 100 asymptomatic midlife adults, aged 43-66, from the PREVENT-Dementia prospective cohort study.
Participants had a hereditary or physiological risk of Alzheimer’s disease, due to either a gene (the APOE-ε4 allele) that puts them at risk of the condition, a family history of Alzheimer’s disease, ...
2024-02-29
A team of researchers led by Alexander Pohle has unveiled a treasure trove of ancient fossils from Queensland's Black Mountain. The findings, published in PeerJ Life & Environment, shed new light on the complex three-dimensional siphuncle morphology of Plectronoceratids, a pivotal group of molluscs from the latest Cambrian period.
The study surpasses the entirety of previously documented Plectronoceratid fossils, presenting over 200 well-preserved specimens. These fossils, meticulously collected by the late Mary Wade and her team during the 1970s and 1980s, offer unprecedented insights into the intricate structures of these ancient creatures.
Pohle's team focused on specimens ...
2024-02-29
A 30 million year-old fossil whale may not be the heaviest animal of all time after all, according to a new analysis by paleontologists at UC Davis and the Smithsonian Institution. The new analysis puts Perucetus colossus back in the same weight range as modern whales and smaller than the largest blue whales ever recorded. The work is published Feb. 29 in PeerJ.
A fossil skeleton of Perucetus was discovered in Peru and described in a paper in Nature last year. The animal lived about 39 million years ago and belonged to an extinct group of early whales called ...
2024-02-29
Improved neutron mirrors can increase the efficiency of material analysis in neutron sources such as the ESS, which is being built outside Lund, Sweden. The improved mirror has been developed by researchers at Linköping University by coating a silicon plate with extremely thin layers of iron and silicon mixed with boron carbide. Their study has been published in the journal Science Advances.
“Instead of increasing the power on the neutron source, which is extremely expensive, it’s better to focus on improving optics,” says Fredrik Eriksson, researcher at the Thin Film Physics Division at Linköping University.
Together with protons, neutrons ...
2024-02-29
Researchers have found water vapour in the disc around a young star exactly where planets may be forming.
Water is a key ingredient for life on Earth and is also thought to play a significant role in planet formation, yet, until now, astronomers have never been able to map how water is distributed in a stable, cool disc — the type of disc that offers the most favourable conditions for planets to form around stars.
For the first time, astronomers have weighed the amount of water vapour around a typical planet-forming star.
The new findings were made possible thanks to the Atacama Large Millimeter/submillimeter Array (ALMA) - a collection of telescopes ...
2024-02-29
A promising new fungicide to fight devastating crop diseases has been identified by researchers at the University of California, Davis. The chemical, ebselen, prevented fungal infections in apples, grapes, strawberries, tomatoes and roses and improved symptoms of pre-existing fungal infection in rice.
Fungal pathogens account for almost a quarter of global crop losses. In the United States, these losses amount to around $150 billion per year. However, fungicide development has been slow for the past 50 years, largely because researchers have had difficulty identifying molecular pathways to target. In a new study published Feb. 29 in ...
2024-02-29
FINDINGS
Researchers from the UCLA Health Jonsson Comprehensive Cancer Center show for the first time that a gene usually linked to giant axonal neuropathy, a rare and severe neurological condition, also plays a role in inhibiting aggressive tumor cell growth in head and neck cancers.
The team found when the specific genetic variant (GAN gene exon 8 SNP T allele) of the GAN gene isn't present, it leads to the production of certain proteins that make cancer cells more likely to spread and become resistant to treatment.
These findings suggest that the presence of the genetic variant and higher expression of the GAN gene product gigaxonin may contribute ...
2024-02-29
Thirteen exceptional endocrine researchers from across Europe and the US have been selected as the 2024-26 cohort of the EJE Rising Star Editorial Board by the European Journal of Endocrinology (EJE), a journal published by the European Society of Endocrinology (ESE).
This prestigious opportunity is given to individuals selected by EJE Editors who show promise, achievement and trajectory as leading clinical and translational researchers in endocrinology, with high potential to serve as future editors of EJE.
Through the Rising Stars Programme, awardees are granted the following:
membership ...
2024-02-29
As an important reproductive organ of angiosperms, flowers have clear purposefulness and adaptive significance in their various characteristics. As a typical floral evolutionary feature, the floral spur is a tubular structure extending from the petal, which has undergone several independent evolutions in angiosperms (e.g., Impatiens, Aquilegia, Linaria, etc.). Meanwhile, it plays a vital role in the pollination process because of its properties of secreting and storing nectar. In addition, the morphology (length, diameter, degree of distortion), ...
2024-02-29
29 February 2024: Lockdowns imposed during the COVID-19 pandemic had an impact on the gut microbiome development of babies born during these periods according to new research from RCSI University of Medicine and Health Sciences, Children’s Health Ireland and APC Microbiome Ireland (APC), a world leading SFI Research Centre, based in University College Cork.
Our gut microbiome, an ecosystem of microbes that live in our digestive tract, plays an essential role in human health. The study published in Allergy is the first to specifically explore the gut health of newborns in the pandemic. ...
LAST 30 PRESS RELEASES:
[Press-News.org] Investigating cell killers: Advanced system for size-dependent cytotoxicity analysis of silica
Scientists present a new analysis technique for size-separated evaluation of silica nanoparticle toxicity toward human hepatoma cells