The Thermogel Chronicle—From Rational Design of Thermogelling Copolymers to Advanced Thermogel Applications
22 Oct 2021-Vol. 2, Iss: 10, pp 881-894
About: The article was published on 2021-10-22 and is currently open access. It has received 14 citations till now.
Citations
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TL;DR: In this article , hydrophobic crosslinking and intermicellar bridge formation were suggested in the aqueous HA-g-PPG/F127 hybrid solutions.
8 citations
TL;DR: In this article , the effects of common inorganic salts on the gelation and micellization properties of a thermogelling polymer containing poly(ethylene glycol), poly(propylene glycol) and poly(caprolactone) components were investigated.
7 citations
TL;DR: A review of the recent developments in temperature-responsive polymers in ophthalmic therapy in the past 5 years including retinal detachment, retinal vascular diseases, dry eyes, cataracts, age-related macular degeneration, and glaucoma can be found in this article .
Abstract: Blindness is one of the most feared disabilities. From cataracts and glaucoma to age-related macular degeneration and retinal vascular diseases, ocular diseases have adverse impacts on patients and pose a huge burden to the healthcare system. The World Health Organization estimates that out of 2.2 billion people with visual impairment, almost half of the cases can be prevented or has yet to be addressed. This presents an urgent clinical and societal need to be met. Temperature-sensitive hydrogels are one of the most biocompatible materials, which can be applied into the eye. By exploiting physiological temperature as a stimulus for in situ gel formation, control of the mechanical properties, rate of drug release, and biomechanical interactions can be tuned. They are very versatile and have immense potential in ocular applications by acting as vitreous substitutes in retinal surgery or topical eye drops and lenses for ocular discomfort and inflammation. In this article, we provide a review of the recent developments in temperature-responsive polymers in ophthalmic therapy in the past 5 years including retinal detachment, retinal vascular diseases, dry eyes, cataracts, age-related macular degeneration, and glaucoma.
4 citations
TL;DR: In this paper , the authors present a review of physical models of hydrogel release and discuss the interesting potential and challenges for programming release, and potential implications with the advent of machine learning.
Abstract: Hydrogels are a promising drug delivery system for biomedical applications due to their biocompatibility and similarity to native tissue. Programming the release rate from hydrogels is critical to ensure release of desired dosage over specified durations, particularly with the advent of more complicated medical regimens such as combinatorial drug therapy. While it is known how hydrogel structure affects release, the parameters that can be explicitly controlled to modulate release ab initio could be useful for hydrogel design. In this review, we first survey common physical models of hydrogel release. We then extensively go through the various input parameters that we can exercise direct control over, at the levels of synthesis, formulation, fabrication and environment. We also illustrate some examples where hydrogels can be programmed with the input parameters for temporally and spatially defined release. Finally, we discuss the exciting potential and challenges for programming release, and potential implications with the advent of machine learning.
3 citations
TL;DR: EPC-DA hydrogels exhibited excellent antifatigue properties with >90% recovery during cyclic compression tests and showed shape stability after application of force and immersion in an aqueous buffer for 35 days.
3 citations
References
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TL;DR: The synthesis of a thermosensitive, biodegradable hydrogel consisting of blocks of poly(ethylene oxide) and poly(L-lactic acid) and aqueous solutions of these copolymers exhibit temperature-dependent reversible gel–sol transitions.
Abstract: Polymers that display a physicochemical response to stimuli are widely explored as potential drug-delivery systems. Stimuli studied to date include chemical substances and changes in temperature, pH and electric field. Homopolymers or copolymers of N-isopropylacrylamide and poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (known as poloxamers) are typical examples of thermosensitive polymers, but their use in drug delivery is problematic because they are toxic and non-biodegradable. Biodegradable polymers used for drug delivery to date have mostly been in the form of injectable microspheres or implant systems, which require complicated fabrication processes using organic solvents. Such systems have the disadvantage that the use of organic solvents can cause denaturation when protein drugs are to be encapsulated. Furthermore, the solid form requires surgical insertion, which often results in tissue irritation and damage. Here we report the synthesis of a thermosensitive, biodegradable hydrogel consisting of blocks of poly(ethylene oxide) and poly(L-lactic acid). Aqueous solutions of these copolymers exhibit temperature-dependent reversible gel-sol transitions. The hydrogel can be loaded with bioactive molecules in an aqueous phase at an elevated temperature (around 45 degrees C), where they form a sol. In this form, the polymer is injectable. On subcutaneous injection and subsequent rapid cooling to body temperature, the loaded copolymer forms a gel that can act as a sustained-release matrix for drugs.
1,930 citations
TL;DR: Aqueous solutions of new biodegradable triblock copolymers, poly(ethylene glycol-b-(dl-lactic acid-co-glycolic acid)-b-ethylenes glycol) (PEG−PLGA−PEG), have shown to have sol-to-gel (lower transiti...
Abstract: Aqueous solutions of new biodegradable triblock copolymers, poly(ethylene glycol-b-(dl-lactic acid-co-glycolic acid)-b-ethylene glycol) (PEG−PLGA−PEG), have shown to have sol-to-gel (lower transiti...
587 citations
TL;DR: This review provides an in-depth summary of the recent progress of thermogelling systems including polymers, low molecular compounds, and nanoemulsions including polymethine, which affect cell proliferation, differentiation, and biomarker expression in three-dimensional cell culture and tissue engineering application.
Abstract: Aqueous solutions that undergo sol-to-gel transition as the temperature increases have been extensively studied during the last decade. The material can be designed by controlling the hydrophilic and hydrophobic balance of the material. Basically, the molecular weight of the hydrophilic block and hydrophobic block of a compound should be fine-tuned from the synthetic point of view. In addition, stereochemistry, microsequence, topology, and nanostructures of the compound also affect the transition temperature, gel window, phase diagram, and modulus of the gel. From a practical point of view, biodegradability, biocompatibility, and interactions between the material and drug or cell should be considered in designing a thermogelling material. The interactions are particularly important in that they control drug release profile and initial burst release of the drug in the drug delivery system, and affect cell proliferation, differentiation, and biomarker expression in three-dimensional cell culture and tissue engineering application. This review provides an in-depth summary of the recent progress of thermogelling systems including polymers, low molecular compounds, and nanoemulsions. Their biomedical applications were also comparatively discussed. In addition, perspectives on future material design of a new thermogelling material and its application are suggested.
339 citations
TL;DR: A novel associated micelle packing model can be proposed for the sol-gel transition for the copolymer gels of this system.
249 citations
TL;DR: The results showed that these nanofiber scaffolds supported excellent cell adhesion, comparable with the pure PCL nanofibers, and could potentially be used as thermoresponsive biodegradable supporting structures for skin tissue engineering applications.
202 citations