Calcium borate hydrate nanoflakes as antimicrobial agents

Introduction Use of antimicrobial agents in building materials, including coatings and paints, has gained more attention as concerns about a complementary strategy for hygiene standards of health impacts in recent years.... [ view full abstract ]

Introduction

Use of antimicrobial agents in building materials, including coatings and paints, has gained more attention as concerns about a complementary strategy for hygiene standards of health impacts in recent years. Adding nontoxic and nonreactive antimicrobial agents on the paint and coating materials can enable environmentally friendly and green technology applications for building materials industry. In our study, we aimed to synthesize Nobleite minerals (calcium borate hydrate) as antimicrobial nanoflake materials for its potential use in paints and coating applications.

Methods

Calcium borate hydrate was synthesized hydrothermally from calcium carbonate and boric acid. A stoichiometric mixture of CaCO3, boric acid and distilled water was ground and mixed for 30 min at 250 rpm in the agate ball mill. The mixture was hydrothermally treated for 5 hours at 110 C in PTFE inserts within steel autoclave. The products were washed with hot distilled water, filtered and dried. The synthesized nanoflakes were investigated by XRD, FTIR, SEM-EDX and electrokinetic potential methods. The antimicrobial properties of the fabricated nanoflakes were assessed against nine common human pathogen microorganisms by disc diffusion assay.

Results

The results demonstrated that nanoflake shaped Nobleite minerals with ̴ 250 nm thickness were successfully synthesized by hydrothermal method (Fig. 1 and Fig.2). We also highlighted that the calcium borate hydrate displayed inhibition zones ranged within 17.47 and 40.05 mm against pathogen microorganisms (Fig. 3). Nobleite nanoflakes interact with bacteria cell wall forming aggregates and destroy the cell wall through polar interactions.

Discussion

The discovery of novel non-toxic, eco-friendly antimicrobial agents such as Nobleite can enable alternative and complementary treatments in painting and coating materials for building materials applications.