Modeling the Properties of Curcumin Derivatives in Relation to the Architecture of the Siloxane Host Matrices

Abstract

Research in the field of natural dyes has constantly focused on methods of conditioning curcumin and diversifying their fields of use. In this study, hybrid materials were obtained from modified silica structures, as host matrices, in which curcumin dyes were embedded. The influence of the silica network structure on the optical properties and the antimicrobial activity of the hybrid materials was monitored. By modifying the ratio between phenyltriethoxysilane:diphenyldimethoxysilane (PTES:DPDMES), it was possible to evaluate the influence the organosilane network modifiers had on the morphostructural characteristics of nanocomposites. The nanosols were obtained by the sol–gel method, in acid catalysis. The nanocomposites obtained were deposited as films on a glass support and showed a transmittance value (T measured at 550 nm) of around 90% and reflectance of about 11%, comparable to the properties of the uncovered support. For the coatings deposited on PET (polyethylene terephthalate) films, these properties remained at average values of T550 = 85% and R550 = 11% without significantly modifying the optical properties of the support. The sequestration of the dye in silica networks reduced the antimicrobial activity of the nanocomposites obtained, by comparison to native dyes. Tests performed on Candida albicans fungi showed good results for the two curcumin derivatives embedded in silica networks (11–18 mm) by using the spot inoculation method; in comparison, the alcoholic dye solution has a spot diameter of 20–23 mm. In addition, hybrids with the CA derivative were the most effective (halo diameter of 17–18 mm) in inhibiting the growth of Gram-positive bacteria, compared to the curcumin derivative in alcoholic solution (halo diameter of 21 mm). The results of the study showed that the presence of 20–40% by weight DPDMES in the composition of nanosols is the optimal range for obtaining hybrid films that host curcumin derivatives, with potential uses in the field of optical films or bioactive coatings.

Optical Behavior of Curcuminoid Hybrid Systems as Coatings Deposited on Polyester Fibers

“…Therefore, it is possible to obtain silica film decorated with organic residues on the surface or as definite regions inside the silica network. The diffusion process of the molecules and, implicitly, the degree of connectivity in the network, are influenced, at the same time affecting the rate of the hydrolysis reaction [41][42][43][44].…”

“…The variation in the fluorescence emission intensity is determined by the polarity of the cavities in which curcumin is sequestered, but also by the concentration of the dye in the composition of the nanosol. The proximity of the dye in the hybrid matrix determines interactions and, thus, pathways to extinguish fluorescence [44].…”

Half-Curcuminoids Encapsulated in Alginate–Glucosamine Hydrogel Matrices as Bioactive Delivery Systems

“…Moreover, the hosting of active compounds in hydrogel matrices led to obtaining materials with fluorescent properties (Figure 5b), directed by the interaction between the host matrix and the hosted half-curcuminoid compounds. Similar to symmetric compounds [38] loaded on different types of carrier matrices, the asymmetric β-diketonic derivatives encapsulated in the hydrogel matrices present two fluorescence emission Moreover, the hosting of active compounds in hydrogel matrices led to obtaining materials with fluorescent properties (Figure 5b), directed by the interaction between the host matrix and the hosted half-curcuminoid compounds. Similar to symmetric compounds [38] loaded on different types of carrier matrices, the asymmetric β-diketonic derivatives encapsulated in the hydrogel matrices present two fluorescence emission maxima.…”

“…Similar to symmetric compounds [38] loaded on different types of carrier matrices, the asymmetric β-diketonic derivatives encapsulated in the hydrogel matrices present two fluorescence emission Moreover, the hosting of active compounds in hydrogel matrices led to obtaining materials with fluorescent properties (Figure 5b), directed by the interaction between the host matrix and the hosted half-curcuminoid compounds. Similar to symmetric compounds [38] loaded on different types of carrier matrices, the asymmetric β-diketonic derivatives encapsulated in the hydrogel matrices present two fluorescence emission maxima. The first emission band at 420 nm is attributed to the chromophore and is common to the obtained composites, while the second emission band is due to the interactions established between the auxochromes grafted on the aromatic ring and functional groups of the carrier matrix.…”

Multifunctional Finishing of Cotton Fabric with Curcumin Derivatives Coatings Obtained by Sol–Gel Method

“…This is easy to apply and very versatile in terms of the active compounds that can be hosted in the resulting gels. Coatings of this type lead to fabrics having various antimicrobial, UV protection, or water repellent properties [10,14,32,39].…”