Enrique Gámez1, Gracia Mendoza1,2, Sofía Salido3, Manuel Arruebo1,2,4, Silvia Irusta1,2,4. 1. Department of Chemical Engineering, Aragon Institute of Nanoscience (INA), University of Zaragoza, Zaragoza, Spain. 2. Aragon Health Research Institute (IIS Aragon), Zaragoza, Spain. 3. Department of Inorganic and Organic Chemistry, Faculty of Experimental Sciences, University of Jaén, Agrifood Campus of International Excellence (ceiA3), Jaén, Spain. 4. Networking Research Center on Bioengineering, Biomaterials and Nanomedicine, CIBER-BBN, Madrid, Spain.
Abstract
Objective: To prepare efficient antibacterial carvacrol (CAR) and thymol (THY)-loaded electrospun polycaprolactone (PCL)-based wound dressings. Approach: Using electrospinning we were able to prepare wound dressings with antimicrobial action thanks to their large surface per volume ratio, which allows their loading with therapeutic amounts of active principles. By nuclear magnetic resonance we demonstrated that the antimicrobial compounds are donors of hydrogen bonds to the ester functional group in PCL, which acts as acceptor and that intermolecular interaction is responsible for the high drug loading achieved. Results: Those mats loaded with CAR and THY without the use of solubilizing agents were able to completely eradicate both Gram-positive (Staphylococcus aureus ATCC 25923) and Gram-negative (Escherichia coli S17 strain) bacteria at doses inferior to the ones needed when using the free nonsupported compounds. A superior antimicrobial action was observed for THY and CAR against Gram-negative bacteria than against Gram-positive bacteria, despite the higher hydrophilicity of the outer layer of Gram-negative bacteria. Innovation: We demonstrate that a direct contact between the bacteria and the dressing is required to elicit antimicrobial action. We also evaluated drug loadings by gas chromatography coupled with mass spectrometry and nuclear magnetic resonance validating a new analytical approach. Finally we were able to visualize the pathogenic bacteria on the dressings by confocal microscopy. Conclusion: The interaction between the PCL-based mat and the pathogenic bacteria is a key issue to achieve complete pathogen eradication. Under no-contact conditions, released CAR or THY from the electrospun mats did not exert any antimicrobial action at the doses tested. Copyright 2019, Mary Ann Liebert, Inc., publishers.
Objective: To prepare efficient antibacterial carvacrol (CAR) and thymol (THY)-loaded electrospun polycaprolactone (PCL)-based wound dressings. Approach: Using electrospinning we were able to prepare wound dressings with antimicrobial action thanks to their large surface per volume ratio, which allows their loading with therapeutic amounts of active principles. By nuclear magnetic resonance we demonstrated that the antimicrobial compounds are donors of hydrogen bonds to the ester functional group in PCL, which acts as acceptor and that intermolecular interaction is responsible for the high drug loading achieved. Results: Those mats loaded with CAR and THY without the use of solubilizing agents were able to completely eradicate both Gram-positive (Staphylococcus aureus ATCC 25923) and Gram-negative (Escherichia coli S17 strain) bacteria at doses inferior to the ones needed when using the free nonsupported compounds. A superior antimicrobial action was observed for THY and CAR against Gram-negative bacteria than against Gram-positive bacteria, despite the higher hydrophilicity of the outer layer of Gram-negative bacteria. Innovation: We demonstrate that a direct contact between the bacteria and the dressing is required to elicit antimicrobial action. We also evaluated drug loadings by gas chromatography coupled with mass spectrometry and nuclear magnetic resonance validating a new analytical approach. Finally we were able to visualize the pathogenic bacteria on the dressings by confocal microscopy. Conclusion: The interaction between the PCL-based mat and the pathogenic bacteria is a key issue to achieve complete pathogen eradication. Under no-contact conditions, released CAR or THY from the electrospun mats did not exert any antimicrobial action at the doses tested. Copyright 2019, Mary Ann Liebert, Inc., publishers.
Authors: Samar A Salim; Elbadawy A Kamoun; Stephen Evans; Shahira H El-Moslamy; Esmail M El-Fakharany; Mohamed M Elmazar; A F Abdel-Aziz; R H Abou-Saleh; Taher A Salaheldin Journal: Int J Nanomedicine Date: 2021-10-11
Authors: Samar A Salim; Elbadawy A Kamoun; Stephen Evans; Tarek H Taha; Esmail M El-Fakharany; Mohamed M Elmazar; A F Abdel-Aziz; R H Abou-Saleh; Taher A Salaheldin Journal: RSC Adv Date: 2021-06-04 Impact factor: 4.036