Influence of the Hydrophobicity of Pluronic Micelles Encapsulating Curcumin on the Membrane Permeability and Enhancement of Photoinduced Antibacterial Activity

Abstract

Apart from its well-known activity as an antimicrobial agent, Curcumin (CURC) has recently started to arouse interest as a photosensitizer in the photodynamic therapy of bacterial infections. The aim of the present study was to evidence the influence of the encapsulation of Curcumin into polymeric micelles on the efficiency of photoinduced microbial inhibition. The influence of the hydrophobicity of the selected Pluronics (P84, P123, and F127) on the encapsulation, stability, and antimicrobial efficiency of CURC-loaded micelles was investigated. In addition, the size, morphology, and drug-loading capacity of the micellar drug delivery systems have been characterized. The influence of the presence of micellar aggregates and unassociated molecules of various Pluronics on the membrane permeability was investigated on both normal and resistant microbial strains of E. coli, S. aureus, and C. albicans. The antimicrobial efficiency on the common pathogens was assessed for CURC-loaded polymeric micelles in dark conditions and activated by blue laser light (470 nm). Significant results in the reduction of the microorganism’s growth were found in cultures of C. albicans, even at very low concentrations of surfactants and Curcumin. Unlike the membrane permeabilization effect of the monomeric solution of Pluronics, reported in the case of tumoral cells, a limited permeabilization effect was found on the studied microorganisms. Encapsulation of the Curcumin in Pluronic P84 and P123 at very low, nontoxic concentrations for photosensitizer and drug-carrier, produced CURC-loaded micelles that prove to be effective in the light-activated inhibition of resistant species of Gram-positive bacteria and fungi.

Intracellular Delivery of Anti-Kirsten Rat Sarcoma Antibodies Mediated by Polymeric Micelles Exerts Strong In Vitro and In Vivo Anti-Tumorigenic Activity in Kirsten Rat Sarcoma-Mutated Cancers

“…According to their physicochemical characterization, PM-KRAS presented the ideal features for intravenous administration, i.e., a mean diameter of 23.65 ± 0.88 nm with a low PdI (0.207 ± 0.012) (Figure J) and a surface charge of −5.43 ± 9.51 mV. It is also possible to observe a peak of small intensity/percentage at a size inferior to 10 nm, which corresponds to non-assembled Pluronic F127 monomers, commonly reported in others studies. , Also, some non-associated KRAS-Ab could be presented, although in residual amounts, as indicated by the therapeutic efficacy results. The mean diameter and PdI values were confirmed by TEM images, where it is also possible to observe the micellar spherical morphology (Figure I).…”

“…It is also possible to observe a peak of small intensity/percentage at a size inferior to 10 nm, which corresponds to non-assembled Pluronic F127 monomers, commonly reported in others studies. 30,31 Also, some nonassociated KRAS-Ab could be presented, although in residual amounts, as indicated by the therapeutic efficacy results. The mean diameter and PdI values were confirmed by TEM images, where it is also possible to observe the micellar spherical morphology (Figure 1I).…”

Strategies for Targeted Delivery via Structurally Variant Polymeric Nanocarriers

“…Nanocarriers such as PMs, [182] liposomes, [182] dendrimers, [183] carbon nanotubes, [184] hydrogels [185] etc. have been functionalized by incorporating photochromic molecules and used in the delivery of anticancers, [186] antiviral, [187] antibacterial drugs [188] and several other cargo. [189] With UV radiation as the source of photosensitization, a major limitation is targeting of deep tissues, and the undesirable UV exposure of surrounding healthy tissues.…”

“…Nanocarriers such as PMs, [182] liposomes, [182] dendrimers, [183] carbon nanotubes, [184] hydrogels [185] etc. have been functionalized by incorporating photochromic molecules and used in the delivery of anticancers, [186] antiviral, [187] antibacterial drugs [188] and several other cargo [189] …”

Revisiting the Solubility–Permeability Relationship with Hydrophobic Drug Umifenovir in Pluronic Solutions: Impact of pH and Co-Solvent

“…As follows, the size of the particles, aggregation, and solubilizing power towards drug compounds can vary in the multicomponent systems. Notably, the number of studies concerning permeability in the presence of block copolymers and ethanol is limited or, to be more precise, tends towards zero [ 29 ]. Deeper investigation of these processes can facilitate the design of effective delivery systems based on the micellar copolymers.…”