Properties of Basil and Lavender Essential Oils Adsorbed on the Surface of Hydroxyapatite.

Carmen Cimpeanu,Daniela Predoi,Florica Barbuceanu,Gabriel Predoi,Mikael Motelica-Heino,Andreea Groza,Regis Guegan,Simona Iconaru

doi:10.3390/ma11050652

Abstract

The research conducted in this study presented for the first time results of physico-chemical properties and in vitro antimicrobial activity of hydroxyapatite plant essential oil against Gram-positive bacteria (methicillin-resistant Staphylococcus aureus (MRSA) and S. aureus 0364) and Gram-negative bacteria (Escherichia coli ATCC 25922). The samples were studied by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy to determine the morphology and structure of the nanocomposites of hydroxyapatite coated with basil (HAp-B) and lavender (HAp-L) essential oils (EOs). The values of the BET specific surface area (SBET), total pore volume (VP) and pore size (DP) were determined. The results for the physico-chemical properties of HAp-L and HAp-B revealed that lavender EOs were well adsorbed on the surface of hydroxyapatite, whereas basil EOs showed a poor adsorption on the surface of hydroxyapatite. We found that the lavender EOs hydroxyapatite (HAp-L) exhibited a very good inhibitory growth activity. The value of the minimum inhibitory concentration (MIC) related to growth bacteria was 0.039 mg/mL for MRSA, 0.02 mg/mL for S. aureus and 0.039 mg/mL E. coli ATCC 25922. The basil EO hydroxyapatite (HAp-B) showed poor inhibition of bacterial cell growth. The MIC value was 0.625 mg/mL for the HAp-B sample in the presence of the MRSA bacteria, 0.313 mg/mL in the presence of S. aureus and 0.078 mg/mL for E. coli ATCC 25922.

Highlights

Hydroxyapatite (HAp) is a calcium phosphate compound and the best known biomaterial in terms of its morphological and compositional similarity with human hard tissue
The results presented in this paper evidence the physicochemical properties and antibacterial activities of hydroxyapatite-lavender essential oil (HAp-L) and hydroxyapatite-basil essential oil (HAp-B) nanocomposites
HAp-L samples revealed the presence of IR absorption bands specific to both HAp and essential oils (EOs). This suggested that both basil and lavender EOs were incorporated into the HAp sample, which is in agreement with the Scanning Electron Microscopy (SEM) analysis and nitrogen adsorption-desorption

Summary

Introduction

Hydroxyapatite (HAp) is a calcium phosphate compound and the best known biomaterial in terms of its morphological and compositional similarity with human hard tissue. Materials 2018, 11, 652 thermodynamic point of view, hydroxyapatite is the most stable calcium phosphate with regard to the physiological conditions of the human body, including temperature, body fluids composition and human pH. Hydroxyapatite inorganic components (Ca10 (PO4 ) (OH)2 ) resemble, in the most favorable way, the natural biological apatite found in bone. It is of interest in medicine and biomedical engineering for bone regeneration and dental applications. As a result of its biocompatibility, hydroxyapatite can be used for coating metal prostheses or dental implants, which is favorable for a successful osteointegration process. It is well known that the risk of postoperative infections [2,3,4] can be drastically reduced by incorporating antibacterial agents in the chemical structure of hydroxyapatite

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