Hypoxia, inflammation, and impaired skin tissue remodeling are three typical features of chronic wounds (CWs). Additionally, CWs are often worsened by fungal infections. Intriguingly, oxygen-loaded nanodroplets (OLNDs) have proven effective in delivering oxygen to hypoxic tissues, restoring normoxia-like levels of inflammatory and matrix-remodeling molecules. On the other hand, chitosan - a natural polysaccharyde suitable for nanodroplet’s shell manufacturing - has displayed anti-fungal properties. Based on this information, in the present work chitosan-shelled/2H,3H-decafluoropentane-cored OLNDs and their oxygen-free counterpart (oxygen-free nanodroplets, OFNDs) were challenged for their anti-fungal activity against Candida albicans and Candida glabrata. Additionally, nanodroplet cytotoxicity and ability to promote cell migration were assessed on human keratinocytes. C. albicans or glabrata growth was monitored upon incubation with/without OLNDs and OFNDs for increasing times (2, 3, 4, 6, and 24 h): according to cell counts, both OLNDs and OFNDs significantly inhibited the growth of either fungal species up to 24 h, thus confirming long-term anti-fungal properties of chitosan in the nanodroplet’s outer shell. Further analysis by confocal microscopy displayed OLND and OFND internalization by Candida spp after 3 and 24 h of incubation. On the other hand, human keratinocytes (HaCaT cell line) were incubated with/without OLNDs or OFNDs for 24 h either in normoxia (20% O2) or hypoxia (1% O2). As assessed by lactate dehydrogenase (LDH) assay, OLNDs did not display cytotoxicity on human keratinocytes, whereas OFNDs slightly did, thereby suggesting a protective role for oxygen in the nanodroplet’s inner core. Finally, results from scratch assay showed a significant hypoxia-dependent inhibition of keratinocyte migratory ability, an effect that was reversed by OLNDs, but not OFNDs. Based on these data, OLNDs appear as innovative and promising anti-fungal devices able to promote repair processes in infected CWs.
Oxygen-loaded chitosan/2H,3H-decafluoropentane nanodroplets as anti-fungal devices to promote wound healing
PRATO, Mauro;FINESSO, NICOLE;MANDRAS, Narcisa;SCALAS, Daniela;ROANA, Janira;MAGNETTO, CHIARA;LUGANINI, ANNA;GULINO, GIULIA ROSSANA;GENOVA, TULLIO;GIRIBALDI, Giuliana;TULLIO, Viviana Cristina
2016-01-01
Abstract
Hypoxia, inflammation, and impaired skin tissue remodeling are three typical features of chronic wounds (CWs). Additionally, CWs are often worsened by fungal infections. Intriguingly, oxygen-loaded nanodroplets (OLNDs) have proven effective in delivering oxygen to hypoxic tissues, restoring normoxia-like levels of inflammatory and matrix-remodeling molecules. On the other hand, chitosan - a natural polysaccharyde suitable for nanodroplet’s shell manufacturing - has displayed anti-fungal properties. Based on this information, in the present work chitosan-shelled/2H,3H-decafluoropentane-cored OLNDs and their oxygen-free counterpart (oxygen-free nanodroplets, OFNDs) were challenged for their anti-fungal activity against Candida albicans and Candida glabrata. Additionally, nanodroplet cytotoxicity and ability to promote cell migration were assessed on human keratinocytes. C. albicans or glabrata growth was monitored upon incubation with/without OLNDs and OFNDs for increasing times (2, 3, 4, 6, and 24 h): according to cell counts, both OLNDs and OFNDs significantly inhibited the growth of either fungal species up to 24 h, thus confirming long-term anti-fungal properties of chitosan in the nanodroplet’s outer shell. Further analysis by confocal microscopy displayed OLND and OFND internalization by Candida spp after 3 and 24 h of incubation. On the other hand, human keratinocytes (HaCaT cell line) were incubated with/without OLNDs or OFNDs for 24 h either in normoxia (20% O2) or hypoxia (1% O2). As assessed by lactate dehydrogenase (LDH) assay, OLNDs did not display cytotoxicity on human keratinocytes, whereas OFNDs slightly did, thereby suggesting a protective role for oxygen in the nanodroplet’s inner core. Finally, results from scratch assay showed a significant hypoxia-dependent inhibition of keratinocyte migratory ability, an effect that was reversed by OLNDs, but not OFNDs. Based on these data, OLNDs appear as innovative and promising anti-fungal devices able to promote repair processes in infected CWs.
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