A self-stabilized and water-responsive deliverable coenzyme-based polymer binary elastomer adhesive patch for treating oral ulcer

Abstract

Oral ulcer can be treated with diverse biomaterials loading drugs or cytokines. However, most patients do not benefit from these materials because of poor adhesion, short-time retention in oral cavity and low drug therapeutic efficacy. Here we report a self-stabilized and water-responsive deliverable coenzyme salt polymer poly(sodium α-lipoate) (PolyLA-Na)/coenzyme polymer poly(α-lipoic acid) (PolyLA) binary synergistic elastomer adhesive patch, where hydrogen bonding cross-links between PolyLA and PolyLA-Na prevents PolyLA depolymerization and slow down the dissociation of PolyLA-Na, thus allowing water-responsive sustainable delivery of bioactive LA-based small molecules and durable adhesion to oral mucosal wound due to the adhesive action of PolyLA. In the model of mice and mini-pig oral ulcer, the adhesive patch accelerates the healing of the ulcer by regulating the damaged tissue inflammatory environment, maintaining the stability of oral microbiota, and promoting faster re-epithelialization and angiogenesis. This binary synergistic patch provided a therapeutic strategy to treat oral ulcer.

Fig. 1. Schematic diagram of preparation and application of polyLA-based adhesive patch.

a Preparation process and structural characteristics of PolyLA; b Preparation process and structural characteristics of PolyLA-Na patch; c Preparation process and structural characteristics of PolyLA-Na/PolyLA binary synergistic adhesive patch; d Illustration of the proposed mechanism of PolyLA-Na/PolyLA patch for promoting oral ulcer healing. LA α-lipoic acid, LA-Na sodium α-lipoate, TNF-α tumor necrosis factor-α, IL-6 interleukin-6.

Fig. 2. Characterizations and molecular dynamics simulation of PolyLA-Na/PolyLA binary synergistic patches.

a Pictures of dry PolyLA, dry PolyLA-Na film and PolyLA-Na/PolyLA patches with different compositions; b Raman spectra of the LA powder, dry PolyLA-Na film, and PolyLA-Na/PolyLA-1.5-1 patch; c FT-IR spectra of the LA powder, dry PolyLA, dry PolyLA-Na film and PolyLA-Na/PolyLA patches with different compositions; d ¹H NMR spectra of dry PolyLA, dry PolyLA-Na, and PolyLA-Na/PolyLA-1.5-1 patch; e–g Molecular dynamics simulation of potential energy of PolyLA, PolyLA-Na and PolyLA-Na/PolyLA-2-1 systems; h Total potential energy value of PolyLA, PolyLA-Na and PolyLA-Na/PolyLA-2-1 systems.

Fig. 3. Crystallization behavior and mechanical properties of PolyLA-Na/PolyLA binary synergistic patches.

a–e XRD patterns of the LA powder, dry PolyLA, dry PolyLA-Na film, and PolyLA-Na/PolyLA patches with different compositions; f Pictures showing the stretching process of PolyLA-Na/PolyLA-1.5-0.8 and PolyLA-Na/PolyLA-3-0.8; g–i Tensile strength of PolyLA-Na/PolyLA patches with different compositions; j–l Ultimate strain of PolyLA-Na/PolyLA patches with different compositions g, j: n = 4 for PolyLA/PolyLA-Na = 0.5, n = 5 for PolyLA/PolyLA-Na = 0.8 and 1; h, k n = 6 for PolyLA/PolyLA-Na = 0.5 and 0.8, n = 7 for PolyLA/PolyLA-Na = 1; i, l n = 6 for PolyLA/PolyLA-Na = 0.5, n = 5 for PolyLA/PolyLA-Na = 0.8 and 1. (All presented data are mean values ± SD. Statistics was calculated by one-way ANOVA followed by Tukey’s post-test).

Fig. 4. Wet adhesion behavior of PolyLA-Na/PolyLA binary synergistic adhesive patches.

a Pictures showing the variation in the water contact angle of PolyLA-Na/PolyLA-1.5-0.5 patch at different times (WC: water contact angle); b The value of water contact angle of the PolyLA-Na/PolyLA adhesive patches with different compositions (n = 4); c Proposed adhesion mechanism of PolyLA-Na/PolyLA adhesive patch; d–g X-ray photoelectron spectra of dry PolyLA-Na film and PolyLA-Na/PolyLA adhesive patches with different compositions (d PolyLA-Na; e PolyLA-Na/PolyLA-1.5-1; f PolyLA-Na/PolyLA-2-1; g PolyLA-Na/PolyLA-3-1); h Adhesion strength of PolyLA-Na/PolyLA adhesive patches with different compositions to oral mucosa tissue after soaking in artificial saliva (n = 4); i Photographs showing the lap-shear process of the PolyLA-Na/PolyLA-2-1 patch adhered to oral mucosa tissue after soaking in artificial saliva. (All presented data are mean values ± SD from the mean from n = 4 independent measurements on independent samples. Statistics were calculated by one-way ANOVA followed by Tukey’s post-test).

Fig. 5. Swelling resistance, LA-Na release, antioxidant and antibacterial properties of PolyLA-Na/PolyLA binary synergistic adhesive patches.

a Swelling behavior of PolyLA-Na/PolyLA adhesive patches with different compositions in artificial saliva (n = 3); b Monomer release ratio of PolyLA-Na/PolyLA adhesive patches with different compositions in artificial saliva for different times (n = 3); c FT-IR spectra of PolyLA-Na/PolyLA adhesive patch before and after monomer release; d Scavenging effect of PolyLA-Na/PolyLA adhesive patches on OH· radicals at 0.5 h (n = 3); e ABTS radical clearance ratio of PolyLA-Na/PolyLA adhesive patches determined at different times (n = 3, ***p < 0.001); f Digital images displaying minimum inhibitory concentration of the PolyLA-Na/PolyLA adhesive patches against E.coli and S.aureus; g, h Sterilization rate of PolyLA-Na/PolyLA adhesive patches with different concentrations against E.coli and S.aureus at different times (n = 3). (All presented data are mean values ± SD from the mean from n = 3 independent measurements on independent samples. All p values were calculated using a two-sided Student’s t test).

Fig. 6. In vivo adhesion and biocompatibility of PolyLA-Na/PolyLA adhesive patch.

a Adhesion of PolyLA-Na/PolyLA patch on the wet surface of the rat buccal mucosa, gingiva, palate mucosa, and tongue; b Movement-resistant adhesion of PolyLA-Na/PolyLA-2-1 patch in vivo; c Adhesion of chitosan film in oral cavity; d Durable adhesion ability of PolyLA-Na/PolyLA-2-1 patch in oral cavity; e, f Live/Dead staining and cell viability of hGFs cells co-cultured with PolyLA-Na/PolyLA patch for 1 and 3 days (n = 4); g H&E staining of buccal mucosa tissue after attachment of PolyLA-Na/PolyLA patch for 12 h (n = 3 biologically independent samples in each group); h H&E staining of main organs after PolyLA-Na/PolyLA patch treatment for 8 days (n = 3 biologically independent samples in each group). (All presented data are mean values ± SD from the mean from n = 4 independent measurements on independent samples. All p values were calculated using a two-sided Student’s t test).

Fig. 7. Oral ulcer healing efficacy of PolyLA-Na/PolyLA patch in rat model.

a Scheme depicting creation of rat mucosa defect that was covered by PolyLA-Na/PolyLA patch or chitosan film to assess healing; b Photographs of buccal mucosa ulcers in rats treated by PolyLA-Na/PolyLA patch and chitosan film at the 0, 2, 4, 6, and 8 days; c Wound healing efficiency of the oral ulcers at days 2, 4, 6, and 8 days after treated with PolyLA-Na/PolyLA patch and chitosan film (n = 3); d, e H&E staining and Masson’s trichrome staining of the regenerated oral mucosa at day 4 and 8 days (n = 3 biologically independent samples in each group); f Immunohistochemistry staining of CK13 antibody in regenerated oral mucosa at 8 days; g immunofluorescence staining of iNOS (green) and MPO (red) antibody in regenerated oral mucosa at 4 days; h–j Quantification of expression levels of CK13, iNOS, and MPO in regenerated oral mucosa (n = 3) CK13 cytokeratin 13, iNOS inducible nitric oxide synthase, MPO myeloperoxidase. (All presented data are mean values ± SD from the mean from n = 3 independent measurements on independent samples. All p values were calculated using a two-sided Student’s t test).

Fig. 8. Effects of different treatments on oral microbiota in rats.

a Venn diagram of the oral microbiota in the normal group, control group, chitosan film group, and PolyLA-based patch group; b,c PCoA and NMDS analyses of the oral microbiota in the normal group, control group, chitosan film group, and PolyLA-based patch group; d Heat map of the oral microbiota in the normal group, control group, chitosan film group and PolyLA-Na/PolyLA patch group; e Cluster analysis of the different groups of oral microbiota at the genus level; f LEfSe analysis identifying the dominant bacteria in the normal group and PolyLA-based patch group; g LEfSe analysis identifying the dominant bacteria in the normal group and chitosan film group.

Fig. 9. Oral ulcer healing efficacy of PolyLA-Na/PolyLA patch in mini-pig model.

a Scheme depicting creation of mini-pig mucosa defect that was covered by PolyLA-Na/PolyLA patch to accelerate healing; b Photographs of buccal mucosa defect in mini-pig treated by PolyLA-based patch and chitosan film at the 0, 3, 5, and 8 days; c Tracking of wound-bed closure after treating with different methods for 0, 3, 5, and 8 days; d Wound healing efficiency of the oral ulcers at days 3, 5, and 8 days after treated with PolyLA-Na/PolyLA patch and chitosan film (n = 3); e, f H&E staining and Masson’s trichrome staining of the regenerated mini-ping oral mucosa at day 8 (n = 3 biologically independent samples in each group); g Sirius red staining of type I collagen (red) and type III collagen (green) in the regenerated mini-ping oral mucosa at day 8; h–j Immunofluorescence staining of CK5 (red), CD31 (red) and iNOS (red) antibody in regenerated oral mucosa at 8 days; k Analysis of the collagen I/III ratio in Sirius red staining (n = 3); l–n Quantification of expression levels of CK5, CD31, and iNOS in regenerated oral mucosa (n = 3) CK5 cytokeratin 5, CD31 platelet endothelial cell adhesion molecule-1, iNOS inducible nitric oxide synthase. (All presented data are mean values ± SD from the mean from n = 3 independent measurements on independent samples. All p values were calculated using a two-sided Student’s t test).