Temperature Induced Gelation and Antimicrobial Properties of Pluronic F127 Based Systems

Abstract

Different formulations containing Pluronic F127 and polysaccharides (chitosan, sodium alginate, gellan gum, and κ-carrageenan) were investigated as potential injectable gels that behave as free-flowing liquid with reduced viscosity at low temperatures and displayed solid-like properties at 37 °C. In addition, ZnO nanoparticles, lysozyme, or curcumin were added for testing the antimicrobial properties of the thermal-sensitive gels. Rheological investigations evidenced small changes in transition temperature and kinetics of gelation at 37 °C in presence of polysaccharides. However, the gel formation is very delayed in the presence of curcumin. The antimicrobial properties of Pluronic F127 gels are very modest even by adding chitosan, lysozyme, or ZnO nanoparticles. A remarkable enhancement of antimicrobial activity was observed in the presence of curcumin. Chitosan addition to Pluronic/curcumin systems improves their viscoelasticity, antimicrobial activity, and stability in time. The balance between viscoelastic and antimicrobial characteristics needs to be considered in the formulation of Pluronic F127 gels suitable for biomedical and pharmaceutical applications.

Photorelease of nitric oxide from Pluronic F127/chitosan hydrogels incorporating a water soluble ruthenium nitrosyl complex

“…This phenomenon of delayed crystallisation was explained by the presence of water bound to the polymer network via hydrogen or van der Waals bonds. 22 As the sample warmed up, two endothermic signals were observed: a first low intensity peak at À15 1C and a second at B5-6 1C about 5-6 times more intense than the first. They were both assigned to the melting of water.…”

Development of an optogenetic gene expression system inLactococcus lactisusing a split photoactivatable T7 RNA polymerase

“…We chose as a starting material Pluronic F-127, a hydrogel commonly used for bacterial encapsulation (51)(52)(53)(54)(55). Pluronic F-127 (PL from now on) is a poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) (PEO-PPO-PEO) amphiphilic triblock copolymer with a lower critical solution temperature (LCST) that reversibly transitions from a low viscosity solution at low temperatures to a hydrogel at higher temperatures (56), becoming a fully crosslinked hydrogel at 30°C, the optimal growth temperature for L. lactis. In the gel phase, PL displays a shear-thinning behaviour that makes it appropriate for cold extrusion-based 3D printing, behaving as a viscous paste that keeps its structural integrity after extrusion.…”

Light-Driven Nanonetwork Assembly of Gold Nanoparticles via 3D Printing for Optical Sensors

“…This transition occurs due to the increased interactions between the dehydrated PEO blocks and the hydrophobic PPO (poly(propylene oxide)) blocks within the micelles. So higher concentrations such as 30 and 35 wt % have more polymer chains to undergo micellization and subsequent gelation. ,, Besides, we also calculated the solidification time of different wt % of Pf-127 solution, and 25 wt % solidifies in ∼2 min, while 30 and 35 wt % solidify within 30 s upon exposure to RT. Even, at lower concentrations, water molecules bonded to Pf-127 through hydrogen bonding.…”

“…When exposed to room temperature, 25 wt % of these concentrations showed excellent stability and perfect solidification time required for the assembly of AuNPs using light, In contrast, 30 and 35 wt % solidified more quickly than 25 wt % due to an increase of polymer chains, facilitating faster micellization and gelation. 41,42 At low temperatures (e.g., below 10 °C), Pf-127 exists as unimers (single polymer chains) with a hydrodynamic diameter (dH) of around 9 nm. As the temperature increases to around 25 °C, the PEO (poly-(ethylene oxide)) blocks of Pf-127 become dehydrated, leading to the formation of micelles with a dH of approximately 30 nm.…”