Graphene Oxide Hybrid Supramolecular Hydrogels with Self‐Healable, Bioadhesive and Stimuli‐Responsive Properties and Drug Delivery Application

Abstract

Self‐healable hydrogels are promising soft materials with great potential in biomedical applications due to their autonomous self‐repairing capability. Although many attempts are made to develop new hydrogels with good self‐healing performance, to integrate this characteristic along with other responsive multifunctions into one hydrogel still remains difficult. Here, a self‐healable hybrid supramolecular hydrogel (HSH) with tunable bioadhesive and stimuli‐responsive properties is reported. The strategy is imparting graphene oxide (GO) nanosheets and quadruple hydrogen bonding ureido‐pyrimidinone (UPy) moieties into a thermoresponsive poly(N‐isopropylacrylamide) (PNIPAM) polymer matrix. The obtained GO–HSH hydrogel shows rapid self‐healing behavior and good adhesion to various surfaces from synthetic materials to biological tissue. In addition, doxorubicin hydrochloride (DOX) release profiles reveal the dual thermo‐ and pH‐responsiveness of the GO–HSH hydrogel. The DOX‐loaded hydrogel can further directly adhere to titanium substrate, and the released DOX from this thin hydrogel coating remains biologically active and has high capability to kill tumor cells.

Self‐Stabilized and Strongly Adhesive Supramolecular Polymer Protective Layer Enables Ultrahigh‐Rate and Large‐Capacity Lithium‐Metal Anode

“…The self‐healable supramolecular polymer PEO–UPy was prepared by reversible addition‐fragmentation chain‐transfer (RAFT) polymerization. As demonstrated by the mechanical property tests (Supporting Information, Figures S1–S6), the PEO–UPy polymer is highly self‐healable and stretchable, attributing to the quadruple‐hydrogen‐bonding interactions of UPy dimers . Note that PEO–UPy polymer can be dissolved in a mixed solvent of 1,3‐dioxolane (DOL) and 1,2‐dimethoxyethane (DME; volume ratio 1:1), as shown in Figure S7 in the Supporting Information, which could lead to instability and disintegration of the polymer‐coating layer once it is directly immersed in electrolytes.…”

“…As demonstrated by the mechanical property tests (Supporting Information, Figures S1-S6), the PEO-UPy polymer is highly self-healable and stretchable, attributing to the quadruple-hydrogen-bonding interactions of UPy dimers. [31,32] Note that PEO-UPy polymer can be dissolved in amixed solvent of 1,3-dioxolane (DOL) and 1,2dimethoxyethane (DME;v olume ratio 1:1), as shown in Figure S7 in the Supporting Information, which could lead to instability and disintegration of the polymer-coating layer once it is directly immersed in electrolytes.I nterestingly,t he polymer can self-stabilize after the contact and reaction with Li metal, which will be discussed later. Furthermore,t he pendant PEO segments can provide an ion-conductive network (with an ionic conductivity of 2.37 10 À5 Scm À1 ;S upporting Information, Figure S8) and homogenize the Li + flux of Li plating/stripping because of the electrostatic interactions between the polar segments and Li ions.T hese unique features render this PEO-UPy supramolecular polymer an appealing artificial SEI for Li metal anodes.…”

Thermoresponsive Nanogels Based on Different Polymeric Moieties for Biomedical Applications

“…Polymer molecular weight can affect LCST. Because of its biocompatibility and low cytotoxicity, PVCL is considered an ideal thermoresponsive polymer for biomedical applications [ 97 , 98 , 99 ], particularly when compared to PNIPAM [ 100 , 101 , 102 ]. PVCL conjugation with hydrophilic units such as PEG or derivatives of PEG enables the synthesis of temperature-responsive block copolymers.…”

Biomedical Applications of Graphene-Based Structures

“…These hydrogels were able to release anticancer drugs more slowly than Pluronic F-127 solution due to the higher binding affinity of hydrophobic drugs to the G/GO present in the gels, which offered an opportunity for controlled release [ 88 ]. In another study, thermoresponsive poly( N -isopropylacrylamide) (PNIPAM) was used as a polymer matrix for GO nanosheets, which resulted in a hybrid, self-healable, supramolecular hydrogel [ 89 ]. Subsequently, Dox was encapsulated in the formed hydrogels and its release from the hybrid hydrogels resulted in the death of most of the human cervical cancer cells (HeLa) after 48 h. T. Kavinkumar et al [ 90 ] prepared rGO–silver nanoparticles (rGO-AgNP) composites by a simple, fast, nontoxic, and eco-friendly approach.…”