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Advanced Nano-Bio-Materials and Devices – AdvNanoBioMD 2020; Vol 4; Issue 3 is now released. Thank you for all the contributors and reviewers!

Advanced Nano-Bio-Materals and Devices – AdvNanoBioMD 2020; Vol 4; Issue 2 (June 30)

The purpose of the study was evaluation of the cytotoxicity of the Agrimoniae herba and Cichorii herba extracts by counting the metabolic activity and the viability of the isolated hepatocytes from the laboratory animals, MTT technique (3- (4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide). Hepatocytes were extracted from the rats of the Wistar line according to the two-stage hepatocyte isolation protocol. Further, cytotoxicity and cell viability of the hepatocytes were determined in vitro after their exposure to the extracts obtained from Agrimoniae herba and Cichorii herba in concentrations of 100, 200, 600 and 1000 mg/ml. The cell viability of hepatocytes treated with the extract from Agrimoniae herba in doses of 100 and 200 mg/ml are 92.78 ± 1.75 % and 79.23 ± 1.49 % and for Cichorii herba in doses of 100 mg/ml and 200 mg/ml constituted respectively 92.07 ± 1.44% and 76.07 ± 1.61 towards the control group; the dose of the 600 mg/ml presents 77.27 ± 2.38% for Agromoniae herba and 57.23 ± 1.38 % for Cichorii herba respectively. The lowest cell viability was attained at the concentration of 1000 mg/ ml, representing 41.6 ± 1.98 % for Cichorii herba and 49.98 ± 3.53 % for Agrimoniae herba, considered to manifest the highest cytotoxic effect. Doses of 100-200 mg/ml obtained from Agrimoniae herba and Cichorii herba demonstrate cell viability and don’t affect hepatocytes, respectively can be used in further studies.

In the present work the effect of doping 1% nano-sized diamond particles on the structure and properties of biocomposites (sintered at 500 and 780 ºC on air) based on biogenic hydroxyapatite and sodium silicate glass were investigated. Volume and mass shrinkages of composites after sintering, their phase composition, microstructure, porosity, mechanical and bioactivity properties were studied. According to the XRD results it was established that sintering temperature and diamond doping does not effect on the phase composition of the biocomposites and only hydroxyapatite phase Ca5(PO4)6(OH) was detected. SEM investigation showed a complex morphology of samples surface and more rounded particles in agglomerates for biocomposites sintered at 500 ºC compared to biocomposites sintered at 780 ºC. The total porosity of the samples depends on the sintering temperature and the doping and is equal to 37-44 %. Experiments in vitro showed solubility of biocomposites in saline at 36.5±0.5 ºC and their mass loss in the first 2 days. Dissolution rate is equal to 0.42-0.78 wt.%/day depending on the sintering temperature and the doping of materials. It was found that doping nano-sized diamond 2 times increases the mechanical strength of biocomposites.

 

Some places are very sensitive to pandemic mass transmission, where a contagious person can easily infect over 50 persons in only 2 minutes of exposure. Facing this pandemic, infrastructure is prone to cascading if appropriate protection measures are not implemented in advance. The novel COVID-19 has some features that put it in the class of nano-bio-robot, and in the class of bio-warfare agents, where an accurate understanding on its propagation means is needed in order to design and implement the most appropriate protection measures. Leaders have to be aware how to increase protection in places where social distancing is difficult to achieve, and in places favoring accumulation of hazardous aerosols. As a compressible bio-nanoparticle with dimensions between 60-140 nm COVID-19 is not retained by normal dry filtration systems conceived for clean rooms, and special measures have to be taken to increase protection, and prevent virus reproduction rate bigger than 1. It is also stated that a single measure is not enough, as “social distancing” did not work well in the US, and an assembly of measures applied in harmony has to be set in place, in order to stop virus propagation. More medical studies are needed in order to better understand the virus, its propagation and consequences of getting infected, where the concept of heard immunity is just wishful thinking driving towards a crippled society.