[EMBARGADO HAST DIC 2021]Antimicrobial effect of nanostructured membranes for guided tissue regeneration: an in vitro study

Abstract

Objective:The purpose of this in vitrostudy was to evaluate the antibacterial effect ofanovel non-resorbable, bioactive polymeric nanostructuredmembrane(NMs), whendoped with zinc, calcium and doxycycline.Methods:A validated in vitrosubgingival biofilm model with six bacterial species (Streptococcus oralis, Actinomyces naeslundii, Veillonela parvula, Fusobacterium nucleatum, Porphyromonas gingivalis andAggregatibacter actinomycetemcomitans)was used. The experimental NMs, with and without beingdoped with doxycycline, calcium and zinc,were placed on hydroxyapatite (HA) discs. As positive control membranes, commercially available dense polytetrafluoroethylene (d-PTFE) membranes were used and,as negative controls,the HA discs without any membrane.The experimental, positive and negative control discs were exposed to a mixed bacterial suspension, at 37ºC under anaerobic conditions,during 12, 24, 48 and 72 hours. The resulting biofilms were analyzed through scanning electron microscopy(SEM),to study their structure,andby quantitative polymerase chain reaction (qPCR),to assess the bacterialload,expressed as colony forming units (CFU) per mL. Differences between experimental and control groups were evaluated with the general linear model and the Bonferroni adjustment. Results:As shown by SEM, all membrane groups,except the NMswith doxycycline,resulted in structured biofilms from 12 to 72 hours. Similarly, only the membranes loaded with doxycycline demonstrated a significant reduction in bacterial load during biofilm development,when compared with the control groups (p<0.001).Significance:Doxycycline-doped nanostructured membranes have an impact onbiofilm growth dynamics by significant reducing the bacterial load.