Recent progress of antibacterial hydrogels in wound dressings

Abstract

Hydrogels are essential biomaterials due to their favorable biocompatibility, mechanical properties similar to human soft tissue extracellular matrix, and tissue repair properties. In skin wound repair, hydrogels with antibacterial functions are especially suitable for dressing applications, so novel antibacterial hydrogel wound dressings have attracted widespread attention, including the design of components, optimization of preparation methods, strategies to reduce bacterial resistance, etc. In this review, we discuss the fabrication of antibacterial hydrogel wound dressings and the challenges associated with the crosslinking methods and chemistry of the materials. We have investigated the advantages and limitations (antibacterial effects and antibacterial mechanisms) of different antibacterial components in the hydrogels to achieve good antibacterial properties, and the response of hydrogels to stimuli such as light, sound, and electricity to reduce bacterial resistance. Conclusively, we provide a systematic summary of antibacterial hydrogel wound dressings findings (crosslinking methods, antibacterial components, antibacterial methods) and an outlook on long-lasting antibacterial effects, a broader antibacterial spectrum, diversified hydrogel forms, and the future development prospects of the field.

Keywords: Antibacterial hydrogels; Antibacterial strategies; Applications; Preparation methods; Wound dressings.

Graphical abstract

Fig. 1

(a) Preparation of hydrogel and hydrogel precursor solution. Chemical composition of the hydrogel precursor solution. The purple, yellow and blue lines indicate PCLPBA, TCS and GelMA, respectively [55]. © 2022 Elsevier Ltd. (b) Schematic illustration of the synthesis of CS, PHEA, CS/PHEA (DN) and CS/PDMAPS/PHEA (TN) hydrogels [56]. © 2018 Elsevier Ltd.

Fig. 2

(a) Hydrogels were prepared based on the reaction of 2-FPBA with PVA and 4-arm PEG-CA [66]. © 2021 Wiley-VCH GmbH. (b) Formation mechanism of CFQ hydrogel (structure of CMCS, 2-FPBA, Que, and conjugate) [67]. © 2022 Acta Materialia Inc. Published by Elsevier Ltd. (c) Schematic diagram of preparation of collagen peptide-functionalized carboxymethyl chitosan and oxidized sodium alginate bivalent network hydrogel dressings [68]. © 2021 Elsevier Ltd. (d) Illustrative formation of the CSPBA/PVA/OHC-PEO-CHO Hydrogel [69]. © 2017 American Chemical Society. (e) Schematic representation of Cur-QCS/PF hydrogel synthesis and surface antibacterial activity [70]. © 2018 Elsevier Ltd.

Fig. 3

(a) Schematic diagram of PEGSD/GTU hydrogel preparation [71]. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. (b) Schematic of the formation of J-1-8Br-cAMP hydrogel [72]. © 2022 Acta Materialia Inc. Published by Elsevier Ltd. (c) Synthesis mechanism of PAAMV hydrogels [74]. © The Royal Society of Chemistry 2021.

Fig. 4

(a) Design of adhesive patches of the Janus GPC hydrogel by regulating the synergistic effects of dopamine and nano-clay [102]. © 2022 Acta Materialia Inc. (b) Schematic diagram of the preparation of SF/Hb/Ga hybrid hydrogel [101]. © 2021 Elsevier B.V. (c) Schematic representation for the preparation of the bioinspired adhesive hydrogel [103]. © 2022, The Author(s). (d) Schematic representation of the design strategy of the physicochemical double crosslinked multifunctional hydrogel [79]. © 2021 Elsevier Ltd.

Fig. 5

(a) Representative images of different stages of the gel formation; schematic of the reaction of carboxymethyl cellulose fiber and epichlorohydrin to form the gel, and antibacterial activity of hydrogels [126]. © 2020 American Chemical Society. (b) The crosslinking mechanism of chitosan, 4r-PEG-NH₂ and 4r-PEG-CHO by Schiff base reaction and optical photographs of antibacterial properties [131]. © 2021 Published by Elsevier Ltd. (c) Schematic representation of the multi-functional hydrogels and antibacterial properties [132]. © 2022 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. (d) The preparation process of GelMA-EGF/Gelatin-MPDA-LZM bilayer hydrogel dressing, application on chronic wound and antibacterial performance [133]. © 2022 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Fig. 6

(a) Schematic of hyaluronic acid/poly(ethylene glycol)/PILs semi interpenetrating polymer network hydrogel dressing formation and antibacterial activity in vivo and in vitro [136]. © 2022 Elsevier B.V. (b) Formation and mechanism of QCS/TA hydrogels, and antibacterial mechanism of hydrogels [142]. © 2022 American Chemical Society.

Fig. 7

(a) The fabrication of carboxymethyl starch/polyvinyl alcohol/citric acid (CMS/PVA/CA) hydrogels and antibacterial properties, biocompatibility tests [195]. © 2020 Elsevier Ltd. (b) Injectable CMCS-brZnO hydrogel wound dressing and antibacterial activity [198]. © 2022 Elsevier B.V.

Fig. 8

(a) Chemical reaction and antibacterial mechanism of dual functional pH-sensitive hydrogel [211]. © 2021 Elsevier Ltd. (b) Schematic illustration of CuS@MoS₂ incorporated hydrogel for rapid bacteria killing and wound healing, SEM morphology of S. aureus (a–c) and E. coli (d–f) after culture on 7.5 ​mg/mL hydrogels with dual light irradiation for 15 ​min and antibacterial activity assay [236]. © 2019 Elsevier B.V.

Fig. 9

(a) Design and characterization of the TCPP-CAT CS/GP hydrogel system [202]. © 2020 Wiley-VCH GmbH. (b) Schematic diagram of the dual-crosslinked hydrogel-based drug delivery system and Tannic acid released from the DC-gels by ultrasound suppresses TNF-α secretion from RAW 264.7 ​cells with LPS stimulation [244]. © 2018, Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature. (c) Scheme of poly(3,4-ethylenedioxythiophene)/Alginate (curcumin)-h hydrogel changes after undergoing −1.0 ​V electrostimulation [210]. © 2020 American Chemical Society (d) Schematic diagram of electrical stimulation repair and antibacterial effect [251]. © The Royal Society of Chemistry 2021.