Browsing by Author "Machado Querido, Micaela"
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- Auto-Disinfectant Acrylic Paints Functionalised with Triclosan and Isoborneol - Antibacterial AssessmentPublication . Machado Querido, Micaela; Paulo, Ivo; Hariharakrishnan, Sriram; Rocha, Daniel; Pereira, Cristiana Costa; Barbosa, Nuno; Bordado, João Moura; Teixeira, João Paulo; Galhano dos Santos, RuiEnvironmental surface contamination with microorganisms is a serious concern worldwide. Triclosan and isoborneol present good antimicrobial activity. Their immobilisation to paint substrates allows for development of a material that stays effective over a longer time. In this work, we disclosed the preliminary studies to evaluate the antimicrobial activity of the active molecule after being functionalised with isocyanates for further immobilisation on the paint substrate. Overall, the newly developed non-release antimicrobial coating provides an effective way of preventing the spread of diseases and has been proven to inhibit bacterial growth and with a considerable antimicrobial activity towards S. aureus, E. coli, and K. variicola at the tested concentrations.
- Optimization of the harvesting and freezing conditions of human cell lines for DNA damage analysis by the alkaline Comet assayPublication . Bessa, Maria João; Brandão, Fátima; Machado Querido, Micaela; Costa Pereira, Cristiana; Valdiglesias, Vanessa; Laffon, Blanca; Carriere, Marie; Teixeira, João Paulo; Fraga, SóniaThe comet assay is a commonly used method for in vitro and in vivo genotoxicity assessment. This versatile assay can be performed in a wide range of tissues and cell types. Although most of the studies use samples immediately processed after collection, frozen biological samples can also be used. The present study aimed to optimize a collection and freezing protocol to minimize the DNA damage associated with these procedures in human cell line samples for comet assay analysis. This study was conducted in glial A172 and lung alveolar epithelial A549 cells. Two cell detachment methods (mechanical vs enzymatic) and two cryoprotective media [FBS + 10% DMSO vs Cell Culture Media (CCM) + 10% DMSO] were tested, and DNA damage assessed at four time points following storage at −80 °C (one, two, four and eight weeks). In both cell lines, no differences in % tail intensity were detected between fresh and frozen cells up to eight weeks, irrespective of the harvesting method and freezing medium used. However, freshly isolated A172 cells exhibited a significant lower DNA damage when resuspended in CCM + 10% DMSO, while for A549 fresh cells the preferable harvesting method was the enzymatic one since it induced less DNA damage. Although both harvesting methods and cryoprotective media tested were found suitable, our data indicate that enzymatic harvesting and cryopreservation in CCM + 10% DMSO is a preferable method for DNA integrity preservation of human cell line samples for comet assay analysis. Our data also suggest that CCM is a preferable and cost-effective alternative to FBS in cryopreservation media. This optimized protocol allows the analysis of in vitro cell samples collected and frozen at different locations, with minimal interference on the basal DNA strand break levels in samples kept frozen up to eight weeks.