A photo-degradable injectable self-healing hydrogel based on star poly(ethylene glycol)-b-polypeptide as a potential pharmaceuticals delivery carrier

Abstract

As one of the most promising biomaterials, injectable self-healing hydrogels have found broad applications in a number of fields such as local drug delivery. However, controlled release of drugs in hydrogels is still difficult to realize up to now. Here, we report a novel photo-degradable injectable self-healing hydrogel based on the hydrophobic interaction of a biocompatible four-arms star polymer, poly(ethylene glycol)-b-poly(γ-o-nitrobenzyl-l-glutamate). The hydrophobic interaction between poly(γ-o-nitrobenzyl-l-glutamate) not only connects poly(ethylene glycol)-b-poly(γ-o-nitrobenzyl-l-glutamate) together with a crosslink but also provides a hydrophobic domain to encapsulate hydrophobic pharmaceuticals such as doxorubicin (DOX). Due to the dynamic character of the hydrophobic interaction, the hydrogel exhibits excellent injectable and self-healing ability. In particular, the photolabile o-nitribenzyl ester group is cleaved under UV irradiation. As a result, the hydrophobic domain transforms into the hydrophilic one and the embedded DOX is released effectively. An increasing release ratio of DOX dramatically enhances the apoptosis ratio of HeLa cells. We expect these attractive properties may be beneficial to practical applications of the hydrogel as an effective local drug delivery means in a truly physiological environment.

An Injectable ROS‐Responsive Self‐Healing Hydrogel Based on tetra‐poly(ethylene glycol)‐b‐oligo(l‐methionine)

“…Figure a,b shows that the mechanical strength of the hydrogel was increased with the augmentation of polymer concentration. Moreover, the mechanical strength of the hydrogels could also be enhanced markedly by increasing the OMeth block length of the polymers . The conjugates assemble into network with hydrophobic core as crosslinkers, the longer block length and higher contents of oligomethionine strengthen the hydrophobic interactions.…”

“…On the basis of the above discussion, Dox as a model drug was loaded and the release profiles from the hydrogels with or without the presence of H 2 O 2 were studied (Figure a). The Dox concentrations in the dialysate were quantified by measuring the absorption intensities at 480 nm against corresponding standard calibration curves, and drug LC% was determined to be 4% and the LE% was estimated to be approximately 40%. Figure d shows the H 2 O 2 ‐dependent cargo release kinetics obtained by incubating the Dox‐loaded hydrogels in PBS with 10 m m H 2 O 2 .…”

Hydrogel Properties and Their Impact on Regenerative Medicine and Tissue Engineering

“…The classification of self-healing mechanisms is summarized in Table 2 and is presented in Figure 3. [66,67] Acylhydrazone bonds [68,69] Microcapsule [70,71] Host-guest interactions [72][73][74] Boronate-diol complexation [75,76] Hydrogen bond [77][78][79] Diels-Alder click chemistry [80][81][82] Hydrophobic interactions [83,84] Disulfide bonds [85,86] π-π stacking [87,88] Imine bonds (Schiff base) [89,90] Electrostatic (or ionic) interaction is based on the interaction between ions incorporated into the HG matrix ( Figure 3A). By the mutual attraction of oppositely charged ions or ions and polymer chains, the HG structure can be reconstructed, e.g., between two pieces of HG placed on each other [66].…”

“…This concept was adopted by Zhao et al to create an HG containing poly(ethylene glycol)-b-polypeptide. The HG was able to enclose and administer doxorubicin, a drug with hydrophobic properties [83]. Voorhaar et al prepared an HG with an ABA block structure, where the hydrophilic moieties were in the center (B) and the hydrophobic moieties (A) responsible for structure crosslinking were in the terminal end [84].…”

Self-Healing Hydrogels with both LCST and UCST through Cross-Linking Induced Thermo-Response

“…Self-healing hydrogels can automatically heal damage and restorethemselves to normality without the intervention of external stimuli, whichis similar to some living organisms. Self-healing hydrogelswith excellent biocompatibility have been developed as a promising and successful material system for many biomedical applications, including biosensors [4], controlled drug delivery [5,6], wound healing [7], etc.…”