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■Bio-mathematics, Statistics and Nano-Technologies: Mosquito Control Strategies
bark inhibited E. coli, S. aureus, Pseudomonas aeruginosa and Acinetobacter baumannii
with minimum inhibitory concentrations (MICs) ranging 0.015% - 0.125%, and all tests
species except P. aeruginosa were inhibited by cinnamon leaf, clove, lemongrass, rose-
wood and thyme EOs with MICs ranging (0.125 - 1.0)% (Elcocks et al. 2020).
EOs could potentially be incorporated into textiles to create antimicrobial fabrics, how-
ever EO compounds are often volatile, and sensitive to light and oxygen. The successful ap-
plication of EOs onto textiles requires a formulation that protects the EOs from volatiliza-
tion and degradation and controls its release rate to prevent unacceptable deterioration of
the final product (Ali et al. 2014; Aziz et al. 2015; Bakry et al. 2016). Encapsulation of
EOs may preserve the functional and physicochemical properties of the oil and allow for
greater durability of the final product (Aziz et al. 2015; Javid et al. 2014). Biopolymers
including chitosan and alginates are an attractive option for encapsulation due to their fa-
vorable biodegradable, biocompatible and mucoadhesive properties (Pedro et al. 2009).
A litsea and lemon EO blend (1:2 ratio, previously shown to be antimicrobial) was
encapsulated with chitosan and sodium alginate within an emulsion. The litsea and lemon
EO encapsulated emulsion showed significant antimicrobial activity; E. coli, S. aureus and
S. epidermidis were reduced by 7 log10 CFU ml-1 within 5 minutes of contact with 1% w/v
emulsion (Figure 12.2). T. rubrum was less susceptible to the EO-encapsulated emulsion,
with a complete inactivation (7 log10 CFU ml-1) after 120 minutes of contact. Tian et al.
(2016) reported that a 10% cinnamaldehyde nanoemulsion only reduced the bacterial load
of E. coli by less than 1 log10 after 4 hours, and between 4 and 9 hours the bacterial load
returned to nearly initial levels. A 0.25% lemon-myrtle oil emulsion achieved an 8 log10
reduction after 15 min of contact (Buranasuksombat et al. 2011).
Figure 12.2: Mosquito repellent efficacy of the cotton fabrics treated with the microencap-
sulated litsea-lemon EO emulsion against Aedes aegypti by using Y-tube olfactometer.