Composite materials with biobased graphene oxide

Målet med projektet var att förbättra polypropens gasbarriär genom att addera olika nanofyllmedel, grafenoxid och kalciumkarbonat. I detta projekt undersöktes främst hur genomsläppligheten av syrgasmolekyler, syrgaspermeabiliteten, ändrades när man tillsätter fyllmedel till polypropen med hjälp av MOCON. Resultaten visade att genomsläppligheten av syrgas minskade något med grafenoxid men blev sämre med den mindre tillsatsen av  kalciumkarbonat. Tester som utfördes gjordes med TGA och DSC men permabilitetstestet framhävs som det mest centrala. Resultaten som erhölls vid permabilitetsundersökningen tros komma av hål i filmerna på molekylär nivå, i dessa hål kan då molekylerna passera igenom filmen fritt.  Övriga resultat pekar på att fyllmedlen inte påverkar polypropens smält- eller kristallisationstemperatur nämnvärt men att dess styrka reduceras.  Då polypropen är en mycket stark polymer så försämrar tillsatsen av fyllmedel styrkan hos materialet, däremot ökade E-modulen. Utöver det verkar inte fyllmedelet ha påverkat de fysikaliska egenskaperna så som Tg och Tc. Samtidigt som den termiska stabiliteten ökade med en tillsatts av GO förändrades den inte nämnvärt när kalciumkarbonat adderades utan den bröts ned vid ungefär samma temperatur som rent polypropen

Fabrication of Magnesium Oxide Nanoparticles by Solvent Alteration and Its Bactericidal Applications

The ever increasing resistance of pathogens towards antibiotics has caused developments of novel antibacterial materials. In this work, magnesium oxide nanoparticles have been synthesized and the synthesis parameters have played an important role in determining the physico-chemical properties of the nanoparticles. Three reaction solvents (water, ethyl alcohol and aqueous cetrimonium-tetrabromide) is employed and the morphological, surface and antibacterial properties of the resultant nanoparticles are compared. Using ethanol has yielded a smaller particle size(~10nm), thus greater surface area than CTAB (~ 17 nm) or water (~ 28 nm). The antibacterial efficacy of these nanoparticles proved an increase in cell reduction against both S. aureus and E. coli. About 3 log reduction in bacterial count was observed by a concentration of 5 mg/ml of MgO synthesized in ethanol. Logistics growth model equation has fitted the growth kinetics of the treated bacteria and the parameters also changed significantly with solvent. The reactive oxygen species generation was found to be time and concentration dependent and the haemolysis of the nanoparticles was much lower than the allowable limit. Confocal and Scanning Electron microscopy were employed for a morphological insight of the treated bacteria, thus proving the use of these nanoparticles in biomedicine

3D imaging and quantification of PLL coated fluorescent ZnO NP distribution and ROS accumulation using laser scanning confocal microscopy

Investigations on nanomedicine involve conventional two dimensional (2D) imaging techniques for observing the nanoparticle internalization at a single time point where various phases of internalization can be overlooked. In contrast, three dimensional (3D) imaging of fluorescent nanoparticles with anticancer potential can be used for obtaining the time course of cellular retention of particles, and cells can be followed for days. This article demonstrates the application of laser scanning confocal microscopy to quantify poly-l-lysine coated fluorescent ZnO nanoparticle retention and reactive oxygen species (ROS) generation using volumetric imaging. Synthesis of these particles allows monitoring of ROS formation, internalization, and cytotoxicity using the same imaging platform that offers an advantage over measurement using various instruments. PLL-coated ZnO particles' ability to induce a significant reduction in cell-viability suggests its potential as a therapeutic agent. The proposed framework opens up a new avenue for investigating mechanistic aspects of ZnO adsorption and the evaluation of therapeutic efficiency. © 2022 American Institute of Chemical Engineers