An in vitro and in vivo study on the properties of hollow polycaprolactone cell-delivery particles

The field of dermal fillers is evolving rapidly and numerous products are currently on the market. Biodegradable polymers such as polycaprolactone (PCL) have been found to be compatible with several body tissues, and this makes them an ideal material for dermal filling purposes. Hollow PCL spheres were developed by the Council for Scientific and Industrial Research (CSIR) to serve both as an anchor point and a ªtissue harbourº for cells. Particles were tested for cytotoxicity and cell adherence using mouse embryo fibroblasts (MEF). MEFs adhered to the particles and no significant toxic effects were observed based on morphology, cell growth, cell viability and cell cycle analysis, suggesting that the particles are suitable candidates for cell delivery systems in an in vivo setting. The objective of providing a ªtissue harbourº was however not realized, as cells did not preferentially migrate into the ported particles. In vivo studies were conducted in BALB/c mice into whom particles were introduced at the level of the hypodermis. Mice injected with PCL particles (ported and nonported; with or without MEFs) showed evidence of local inflammation and increased adipogenesis at the site of injection, as well as a systemic inflammatory response. These effects were also observed in mice that received apparently inert (polystyrene) particles. Ported PCL particles can therefore act as a cell delivery system and through their ability to induce adipogenesis, may also serve as a dermal bulking agent.S1 File. Figure A: Chronic inflammation in the test animals over the trial period. Figure B: Acute inflammation in the test animals over the trial period. Figure C: Tissue necrosis in the test animals over the trial period. Figure D: Fibrosis in the test animals over the trial period. Figure E: Granulomatous/foreign body response in the test animals over the trial period. Figure F: Representative TEMs of skin biopsies of particles group (A) and particles+MEFs group (B) in the in vivo experiment injecting particles+MEFs. Particles could be identified in skin biopsies of both the particles and particles+MEFs groups. The aim of the TEM investigation was to determine if any cells could be detected inside the particles. No cells were present inside the particles in either group. These results reflect the conclusion that was made after the light microscopy study, indicating that cells did not migrate into the ported PCL particles. Bar in A = 5μm and in B = 10μm.S2 File. In vitro and in vivo data. Table A: Groups of rats used in the biotoxicity trial. Table B: Observations on mice in the in vivo experiment assessing the effect of ported PCL particles and cells. Table C: Statistical comparisons preformed between the various white blood cell types assessed from blood smears of experimental mice injected with ported PCL particles with or without MEFs. Table D: Schedule of the in vivo experiment assessing the effect of ported and non-ported PCL as well as polystyrene (PS) particles. Table E: Overview of the animals, tests and procedures performed in the in vivo experiment assessing the effect of ported and non-ported PCL as well as polystyrene (PS) particles in BALB/c mice.S3 File. All data underlying the findings of the study.The Council for Scientific and Industrial Research, South Africa, by the Institute for Cellular and Molecular Medicine of the University of Pretoria and by the South African Medical Research Council (Flagship Award SAMRC-RFA-UFSP-01-2013/ STEM CELLS and the SAMRC Extramural Unit for Stem Cell Research and Therapy).http://www.plosone.orgam2019ImmunologyPhysiolog

The environmental literacy level of pre-service teacher trainees at selected campuses of Vista University

M.Ed.Because of the current curriculum developments, it is important that universities begin assessing their status regarding environmental education. This study will therefore aim at determining the current level of environmental awareness of third year pre-service teacher trainees at Vista University in order to make recommendations as to what an environmental education course should contain for the pre-service teacher trainees of this institution. Vista University consists of seven campuses, each accessible to the areas they serve. The different campuses are: Bloemfontein Campus outside Bloemfontein, East Rand Campus near Daveyton on the East Rand, Mamelodi Campus near Silverton in Pretoria East, Port Elizabeth Campus outside Port Elizabeth, Sebokeng Campus near Vereeniging, Soweto Campus in Soweto, and Welkom Campus outside Welkom. Vista University also provides Distance Education, the campus of which is situated in Pretoria. The university's Head Office is situated in Pretoria. This study will limit itself to two campuses within Gauteng, namely East Rand Campus, and Mamelodi Campus, AIMS OF THE STUDY As already mentioned, this survey will be conducted amongst the third year education students on each of the above-mentioned campuses. In order to assess the current status of environmental literacy at Vista University, this study will aim at the following: • to set up a questionnaire to measure the four stages of environmental literacy as set out by Roth (1992: 18 - 19); to undertake the survey amongst the third year education students of the East Rand and Mamelodi Campuses; to analyse and evaluate the data in order to determine the level of environmental awareness of the target group; to generalise the result of the sample to the population; to make suggestions as to what information needs to be included in an environmental education course for pre-service teacher trainees at Vista Universit

Old Merensky Library

Photos of a model (1:100) of Old Merensky Library, University of Pretoria, accompanied by a poster, created by Andri Swanepoel, 3rd year B.Sc.(Arch) student, University of Pretoria , 2006

Preparation and surface-functionalization of dye-doped bioconjugated poly(styrene-co-maleimide) nanoparticles

Thesis (MSc)--Stellenbosch University, 2014.ENGLISH ABSTRACT: Standard methods used for detection of microbial contamination in water and food are based on culturing of samples to increase the number of bacteria present to a detectable level. These tests are however time-consuming (requiring one to two days for results to be generated) and labour intensive. The study described in this dissertation aims to develop dye-doped poly(styrene-co-maleimide) nanoparticles conjugated to antibodies for the rapid (within a few hours) detection of E. coli in water via clustering of the nanoparticles around bacteria to create a concentrated and localised fluorescent signal. Pristine and dye-doped nanoparticles were synthesised according to a one-step (published) method, and surface-functionalised with formaldehyde and three different diamine compounds. The percentage dye added to the particles was also varied in the study. The functionalised nanoparticles were characterised via FTIR, TEM, DSC, and Zetasizer. The emission properties of the dye-loaded NPs were measured with a spectrofluorometer. The functionalised nanoparticles were bioconjugated with avidin and antibodies. The extent of avidin attachment was quantified via the use of a biotin(5-fluorescein) conjugate and via an avidin titration assay. The functionality of the bioconjugated nanoparticles was tested via a sandwich assay and a centrifuge based assay with E. coli cultures. Fluorescence microscopy was also utilised to demonstrate the utility of the particles in creating localised fluorescent signals indicating the presence of E. coli cells

A Comparative Study on the Aerobic Biodegradation of the Biopolymer Blends of Poly(butylene succinate), Poly(butylene adipate terephthalate) and Poly(lactic acid)

The aim of the present work is to evaluate the rate and mechanisms of the aerobic biodegradation of biopolymer blends under controlled composting conditions using the CO2 evolution respirometric method. The biopolymer blends of poly (butylene adipate terephthalate) (PBAT) blended with poly (lactic acid) (PLA), and PBAT blended with poly (butylene succinate) (PBS) by melt extrusion, were tested to evaluate the amount of carbon mineralized under home and industrial composting conditions. The changes in the structural, chemical, thermal and morphological characteristics of the biopolymer blends before and after biodegradation were investigated by FT-IR, DSC, TGA, XRD and SEM. Both blends showed higher degradation rates under industrial composting conditions, when compared to home composting conditions. This was confirmed by FT-IR analysis showing an increase in the intensity of hydroxyl and carbonyl absorption bands. SEM revealed that there was microbial colony formation and disintegration on the surfaces of the biopolymer blends. The obtained results suggest that industrial composting conditions are the most suitable for an enhanced biodegradation of the biopolymer blends viz PBAT–PBS and PBAT–PLA

Supercritical antisolvent co-precipitation of rifampicin and ethyl cellulose

International audienc

Microencapsulation of eucalyptol in polyethylene glycol and polycaprolactone using particles from gas-saturated solutions

Eucalyptol is the natural cyclic ether which constitutes the bulk of terpenoids found in essential oils of Eucalyptus spp. and is used in aromatherapy for treatment of migraine, sinusitis, asthma and stress. It acts by inhibiting arachidonic acid metabolism and cytokine production. Chemical instability and volatility of eucalyptol restrict its therapeutic application and necessitate the need to develop an appropriate delivery system to achieve extended release and enhance its bioactivity. However, the synthesis method of the delivery system must be suitable to prevent loss or inactivation of the drug during processing. In this study, supercritical carbon dioxide (scCO2) was explored as an alternative solvent for encapsulation and co-precipitation of eucalyptol with polyethylene glycol (PEG) and/or polycaprolactone (PCL) using the particles from gas-saturated solution (PGSS) process. Polymers and eucalyptol were pre-mixed and then processed in a PGSS autoclave at 45 °C and 80 bar for 1 h. The mixture in scCO2 was micronized and characterized. The presence of eucalyptol in the precipitated particles was confirmed by infrared spectroscopy, gas chromatography and mass spectrometry. The weight ratios of PEG–PCL blends significantly influenced loading capacity and encapsulation efficiency with 77% of eucalyptol encapsulated in a 4 : 1 composite blend of PEG–PCL. The particle size distribution of the PGSS-micronized particles ranged from 30 to 260 μm. ScCO2 assisted microencapsulation in PEG and PCL reduced loss of the volatile drug during a two-hour vaporization study and addition of PCL extended the mean release time in simulated physiological fluids. Free radical scavenging and lipoxygenase inhibitory activities of eucalyptol formulated in the PGSS-micronized particles was sustained. Findings from this study showed that the scCO2-assisted micronization can be used for encapsulation of volatile drugs in polymeric microparticles without affecting bioactivity of the drug.National Research Fund, South Africahttp://pubs.rsc.org/en/journals/journalissues/rahj2020Zoology and Entomolog

An <i>in vitro</i> and <i>in vivo</i> study on the properties of hollow polycaprolactone cell-delivery particles - Fig 1

<p><b>A) Optical image of ported PCL ported particles; B) SEM image of a ported PCL particle.</b> A: scale bar = 100 μm and B: scale bar = 10 μm.</p

Acridine orange-stained MEFs attached to ported PCL particles.

<p>Cells were propagated in glass Kimble tubes together with particles (A and B) and stained 24 h after seeding. MEFs attached to particles as clumps.</p

An <i>in vitro</i> and <i>in vivo</i> study on the properties of hollow polycaprolactone cell-delivery particles - Fig 8

<p><b>Light microscopy images (A-D), scanning electron micrographs of fibrin networks (E-H) and red blood cells (I-L) for controls, non-ported PCL particles, ported PCL particles and PS particles in BALB/c mice after three weeks exposure.</b> Fibrous thickening, leukocyte infiltration and adipocyte formation occurred in the hypodermis in all animals that received particles when compared to controls (A-D). By SEM, a fine fibrin fibre network (E) and healthy red blood cells (I) were observed in controls. However, a thickened and matted fibrin network and changes in red blood cell morphology indicative of inflammation were observed in mice injected with non-ported PCL particles (F and J), ported PCL particles (G and K) and PS particles (H and L). Scale bar in A-D = 50 μm, and in E, J and L = 2 μm, F-H = 200 μm; and in I and K = 1 μm.</p