In situ forming mesoporous polydopamine nanocomposite thermogel for combined chemo-photothermal therapy of intraocular cancer

Poly(l-threonine-co-l-threonine Succinate) Thermogels for Sustained Release of Lixisenatide

“…Since the pioneering research on a poly(lactide- co -glycolide)/poly(ethylene glycol) (PLGA/PEG) system as a biodegradable thermogel, various systems, such as polycaprolactone/PEG, polyphosphazene/PEG, chitosan/glycerol phosphate, glycochitosan hexanol, and PEG/polyester multiblock copolymers, and polypeptide/PEG have been reported for their characteristic transition mechanism and potential biomedical applications. − The sol-to-gel transition mechanism of PLGA/PEG thermogel involves dehydration, followed by hydrophobic aggregation of semibald micelles. , In the case of polypeptide/PEG systems, changes in polypeptide secondary structure as well as dehydration of the PEG block were reported. , Chitosan/glycerol phosphate systems undergo thermogelation through hydrophobic aggregation involving deprotonation of ammonium groups of chitosan and increased ionic strength of phosphate salts . Recently, thermogel composite systems containing nano/microparticles, such as hydroxyapatite, silica, polyhedral oligomeric silsesquioxanes (POSS), and metal–organic framework (MOF) have been investigated to control mechanical properties as well as drug release profiles. − The facile control of sol-to-gel transition temperatures and mechanical properties by variations in polymer concentration and composition, minute polymer structural changes, and the addition of external substances are other advantages of thermogels. , The sol-to-gel transition properties of an aqueous polymer solution can even be tuned by mixing polymers with different transition temperatures. , Furthermore, the simple mixing of the aqueous polymer solution and drugs for injectable formulation and microfiltration for sterilization are additional advantages of thermogels. Various thermogel applications have been reported, including drug delivery, postsurgical adhesion prevention, three-dimensional cell culture, injectable tissue engineering, long-acting anesthetics, and wound dressing. ,− As drug delivery systems, however, thermogels suffer from an initial burst release of hydrophilic drugs, such as polypeptides and protein drugs, due to the partitioning of the drug in the hydrophilic PEG domain of the gel, as well as weak interactions between the drug and polymers.…”