Poly Ethylene Glycol (PEG)‐Based Hydrogels for Drug Delivery in Cancer Therapy: A Comprehensive Review

Abstract

Hydrogel-based drug delivery systems (DDSs) can leverage therapeutically beneficial outcomes in cancer therapy. In this domain, polyethylene glycol (PEG) has become increasingly popular as a biomedical polymer and has found clinical use. Owing to their excellent biocompatibility, facile modifiability, and high drug encapsulation rate, PEG hydrogels have shown great promise as drug delivery platforms. Here, the progress in emerging novel designs of PEG-hydrogels as DDSs for anti-cancer therapy is reviewed and discussed, focusing on underpinning multiscale release mechanisms categorized under stimuli-responsive and non-responsive drug release. The responsive drug delivery approaches are discussed, and the underpinning release mechanisms are elucidated, covering the systems functioning based on either exogenous stimuli-response, such as photo-and magnetic-sensitive PEG hydrogels, or endogenous stimuli-response, such as enzyme-, pH-, reduction-, and temperature-sensitive PEG hydrogels. Special attention is paid to the commercial potential of PEG-based hydrogels in cancer therapy, highlighting the limitations that need to be addressed in future research for their clinical translation.

Chemical and Structural Engineering of Gelatin-Based Delivery Systems for Therapeutic Applications: A Review

“…The surface-modified PEG chains act as a steric hindrance mechanism, preventing protein binding and preferential uptake by the RES. PEG with a molecular weight of 200–6000 is typically preferred because those molecules are likely to penetrate tissues, offering better permeability and biocompatibility . Additionally, small PEGs can be leveraged to increase the stability and water solubility of the drug, as well as lengthen its duration in the body’s circulation.…”

“…Diagrammatic representation of the GNPs’ preparation via the desolvation method. Reproduced with permission from ref . Copyright 2019 Elsevier.…”

Nanomaterials as Theranostic Agents for Cancer Therapy

“…Organic polymer nanoparticles have been intensively studied as theranostic agents due to their many advantages and high cancer therapeutic effectiveness. − Various types of natural and synthetic polymers are used for cancer therapy. To reduce toxicity and potential side effects, biodegradable polymers are commonly employed as the primary materials. , These include chitosan, poly­(lactic acid), gelatin, poly­[ N -(2-hydroxypropyl) methacrylamide] (HPMA), as well as their copolymers like poly­(lactide- co -glycolide- co -caprolactone) and poly­(lactic- co -glycolic acid) and synthetic polymers like polyurethane, poly­(ethylene glycol), poly­(ethylamine), etc. Several kinds of polymer nanoparticles have been designed to ease the administration of chemotherapy to malignant tissues, such as polymer conjugate complexes, polymer micelles, polymer nanospheres, and dendritic polymers.…”

3D shape morphing of stimuli-responsive composite hydrogels

“…Owing to the advantage of easy modification for PEG hydrogels, they are broadly applied in the biomedical field, such as tumor treatments. 119 As shown in Fig. 3c, PEG chains are modified by amino acid first and then connect two DNA molecules with complementary sequences.…”