Attenuating Fibrotic Markers of Patient-Derived Dermal Fibroblasts by Thiolated Lignin Composites

Abstract

Engineering composite biomaterials requires the successful integration of multiple feedstocks to formulate a final product for functional improvement. Here we engineered biomaterial scaffolds to attenuate the fibrotic phenotype exhibited by high scarring (HS) patient-derived dermal fibroblasts (hdFBs) by valorizing lignosulfonate from waste feedstocks of lignin. We utilized phenolic functional groups of lignosulfonate to impart antioxidant properties and the cell binding domains of gelatin to enhance cell adhesion for poly(ethylene glycol)-based scaffolds. Highly efficient chemoselective thiol-ene chemistry was utilized for the formation of composites with thiolated lignosulfonate (TLS) and methacrylated fish gelatin (fGelMA) in the PEG(poly (ethylene glycol))-diacrylate matrix. Antioxidant properties of lignosulfonate was not altered after thiolation and the levels of antioxidation were comparable to a well-known antioxidant, <i>L</i>-ascorbic acid, as evidenced by DPPH (2,2-diphenyl-1-picrylhydrazyl) and TAC (Total Antioxidant Capacity) assays. Unlike porcine gelatin, fGelMA remained liquid at room temperature and exhibited low viscosities, resulting in no issues of miscibility when mixed with PEG. PEG-fGelMA-TLS composites significantly reduced the differential of five different fibrotic markers (<i>COL1A1, ACTA2, TGFB1 </i>and<i> TGFB1</i>) between HS and low scarring (LS) hdFBs, providing the potential utility of TLS in a biomaterial scaffold to attenuate fibrotic responses.

Tailoring Physical Properties of Dual-Network Acrylamide Hydrogel Composites by Engineering Molecular Structures of the Cross-linked Network

“…Methacrylate incorporation was conducted using previously published protocols. 34 Briefly, either porcine or fish skin gelatin (10 g) was mixed in 100 mL of DMSO and stirred at 50 °C until the solution was fully dissolved. GMA (4 mL) and DMAP (0.6 g) were added to the gelatin/DMSO solution, and the reaction mixture was stirred at 50 °C for 2 days.…”

“…TLS was synthesized by following the protocol published in the literature. 34 SLS (1.00 g) was dissolved in 10 mL of deionized water in a round bottom flask equipped with a magnetic stirring bar. A mixture of HCl 0.1 mL and MPA 1.0 mL was added to the SLS solution with N 2 purging.…”

“…53 TLS bears multiple sulfhydryl groups, enabling us to utilize the thiol−ene crosslinking reaction. 34,36 Therefore, TLS plays the role of nanoparticle cross-linker and filler in a hydrogel composite. Incorporation of TLS into PAAm and PNIPAm hydrogels with Alg, Gel, GelMA, and GelMA−DOPA (Figure 5b,d, summarized in Table S4) exhibited largely similar trends of stress−strain curves in comparison to the acrylamide hydrogel composites without TLS (Figure 5a,c, summarized in Table S3).…”

Lignin Composites with Sustained Oxygenation and Reactive Oxygen Species-Scavenging Improve Neovascularization and Healing of Diabetic Wounds

“…Precursors of lignin composites were reconstituted in 1 mg/mL LAP (Lithium phenyl-2,4,6-trimethylbenzoylphosphinate) in PBS. The final concentrations were 50 mg/mL gelatin methacrylate (GelMA) [57,59] with TLS (3 mg/mL) plus either CPOc (4 mg/mL, CPO control -SLS particles formed without CaO2) or CPO (4 mg/mL, SLS particles formed with CaO2).…”

“…Thus, we have sought to apply lignin in this study, topically, to diabetic wounds. We have produced a novel, dual action lignosulfonate-composite biomaterial incorporating 1) thiolated lignosulfonate (TLS) nanoparticles for antioxidation [57] and 2) sodium lignosulfonate (SLS)-based, calcium peroxide nanoparticles (termed CPO) for controlled release of oxygen, that not only scavenges reactive oxygen species but also produces oxygen without increasing detrimental byproducts (i.e. H 2 O 2 ), to serve as a correcting, provisional matrix for diabetic wounds.…”