Synthesis of Submicrocontainers with “Green” Biocide and Study of Their Antimicrobial Activity

Saule Aidarova,Altynay Sharipova,Aiym Tleuova,Assem Issayeva,Madina Dzhakasheva,Reinhard Miller,Dmitry Grigoriev,Dariga Kudasova,Botagoz Mutaliyeva

doi:10.3390/colloids2040067

Abstract

The synthesis and properties of submicrocontainers with a shell of nanoparticles of silicon dioxide and a core of polymerized 3-(Trimethoxysilyl) propyl methacrylate loaded with 5-Dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT) are considered. The resulting containers were characterized by scanning electron microscopy SEM, laser correlation spectroscopy and thermogravimetric analysis. The obtained submicrocontainers show low polydispersity with a small increase in size in comparison with the initial droplet size of the Pickering emulsion. The Zeta potential of the final containers was sufficiently negative at pH7 to be stable. The maximum release of encapsulated biocide was observed over approximately 24–27 h with a lease of about 78% of the encapsulated biocide during 3.5 h. The effectiveness of the encapsulated biocide by the Pickering emulsion technique was studied by tests on the growth rate of a microfungi colony (Aspergillus niger, Aspergillus awamori) and the growth rate of the bacteria Bacillus cereus. The test shows that the submicrocontainers of DCOIT facilitate a growth inhibition of 70% against 52% for the free biocide after 5 days; this is due to the fact that free biocide loses its activity promptly, while the encapsulated biocide is released gradually, and thus retains its effectivity for a longer time.

Highlights

Great attention is paid to the formation of stable emulsions, as such systems have a wide range of applications, for example, for the microencapsulation of various active agents
Four microbial strains were used for the assessment of antimicrobial activity of microspheres with and without loaded DCOIT: Aspergillus niger, Aspergillus awamori, as representatives of fungi, and Bacillus cereus as a representative of bacteria
The optimal parameters of this process and the composition were determined by scanning electron microscopy SEM, laser correlation spectroscopy, and thermogravimetric analysis

Summary

Introduction

Great attention is paid to the formation of stable emulsions, as such systems have a wide range of applications, for example, for the microencapsulation of various active agents. Many works were devoted to the development of systems for producing micro-and nanoparticles and for this purpose different techniques were used, such as microemulsion extrusion [1,2], precipitation [3], complexation of hydrogels [4], spray-drying [5] Microencapsulation solves problems such as storage of antimicrobial and other important properties, protection of unsustainable substances from the effect of an external environment, surface functionalization allowing targeted delivery, and keeping a prolonged and controlled release during the application [1,3]. Solid particles attached to the oil–water interface are partly immersed in water and partly in the oil medium, i.e., both oil and water wet their surface sufficiently Both o/w and w/o emulsions can be prepared depending on the wetting conditions and/or the type of the emulsification process [7,8,9,10,11,12,13,14,15,16,17]

Methods

Results

Conclusion