Antifungal Activity of Commercial Essential Oils and Biocides against Candida Albicans.

Management of oral candidosis, most frequently caused by Candida albicans, is limited due to the relatively low number of antifungal drugs and the emergence of antifungal tolerance. In this study, the antifungal activity of a range of commercial essential oils, two terpenes, chlorhexidine and triclosan was evaluated against C. albicans in planktonic and biofilm form. In addition, cytotoxicity of the most promising compounds was assessed using murine fibroblasts and expressed as half maximal inhibitory concentrations (IC50). Antifungal activity was determined using a broth microdilution assay. The minimum inhibitory concentration (MIC) was established against planktonic cells cultured in a range of concentrations of the test agents. The minimal biofilm eradication concentration (MBEC) was determined by measuring re-growth of cells after pre-formed biofilm was treated for 24 h with the test agents. All tested commercial essential oils demonstrated anticandidal activity (MICs from 0.06% (v/v) to 0.4% (v/v)) against planktonic cultures, with a noticeable increase in resistance exhibited by biofilms (MBECs > 1.5% (v/v)). The IC50s of the commercial essential oils were lower than the MICs, while a one hour application of chlorhexidine was not cytotoxic at concentrations lower than the MIC. In conclusion, the tested commercial essential oils exhibit potential as therapeutic agents against C. albicans, although host cell cytotoxicity is a consideration when developing these new treatments.

Osteoblast activity on carbonated hydroxyapatite.

Hydroxyapatite (HA), has been used commonly as a bone substitute and as a scaffold in bone tissue engineering. However it has certain drawbacks such as limited biodegradability and osteointegration properties. Other forms of HA, for example, carbonated hydroxyapatite (CHA) could prove to have enhanced bioactivity as they more closely mimic the chemical composition of the apatite found in human bone. The aim of this study was to test the efficacy of CHA in comparison to HA used as a control. The CHA (4.9 wt %) and the HA discs were seeded with MC3T3-E1 osteoblastic cells. Results revealed a trend of increased cell attachment on the HA discs at day 0, however, the cell proliferation on the CHA discs at 7 and 28 days showed no significant difference in comparison to the HA control. SEM of the CHA discs showed surface irregularities at 7 days indicating dissolution. Also at 7 days, SEM demonstrated cell attachment and extracellular matrix production on both the CHA and HA samples. There was no significant difference in the total amount of collagen produced in the CHA samples relative to the HA control samples at 28 days as evaluated by the hydroxyproline assay. Real time PCR revealed mRNA increase by 2.08, 7.62, and 9.86 fold for collagen I a1, collagen III a1, and osteocalcin respectively on the CHA as compared to the HA discs. This study demonstrates the use of CHA as a biocompatible material that has potentially increased biodegradation properties and osteogenic capability in comparison to HA.

Mesenchymal stem cells, osteoblasts and extracellular matrix proteins: enhancing cell adhesion and differentiation for bone tissue engineering.

Cell adhesion to scaffolds has remained one of the challenges in tissue engineering. Although protein surface modification has been proven to enhance cell adhesion and retention, its specificity depending on cell and biomaterial types means that the best protein and concentration must be established for each specific application. This review focuses on the improvement of cell adhesion for human mesenchymal stem cells with an osteogenesis approach. A brief outline of the cell adhesion process and extracellular matrix proteins precedes an overview of works focused on the adhesion of mesenchymal stem cells and osteoblasts to biomaterials and this effect in their differentiation into osteoblasts.