An in vitro assessment of the response of THP‐1 macrophages to varying stiffness of a glycol‐chitosan hydrogel for vocal fold tissue engineering applications

Abstract

The physical properties of a biomaterial play an essential role in regulating immune and reparative activities within the host tissue. This study aimed to evaluate the immunological impact of material stiffness of a glycol‐chitosan hydrogel designed for vocal fold tissue engineering. Hydrogel stiffness was varied via the concentration of glyoxal cross‐linker applied. Hydrogel mechanical properties were characterized through atomic force microscopy and shear plate rheometry. Using a transwell setup, macrophages were co‐cultured with human vocal fold fibroblasts that were embedded within the hydrogel. Macrophage viability and cytokine secretion were evaluated at 3, 24, and 72 hr of culture. Flow cytometry was applied to evaluate macrophage cell surface markers after 72 hr of cell culture. Results indicated that increasing hydrogel stiffness was associated with increased anti‐inflammatory activity compared to relevant controls. In addition, increased anti‐inflammatory activity was observed in hydrogel co‐cultures. This study highlighted the importance of hydrogel stiffness from an immunological viewpoint when designing novel vocal fold hydrogels.

In Vitro Evaluation of Biomaterials for Vocal Fold Injection: A Systematic Review

“…All of the studies were published between January 2010 and March 2021. In general, ten studies aimed to develop new formulation of biomaterials [ 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 ]; three studies focused in improving or characterizing current biomaterials [ 46 , 47 , 48 ]; one study investigated the effect of the biomaterials toward inflammation [ 49 ]; three studies intended to improve fabrication methods in order to produce better biomaterials [ 36 , 46 , 50 ]. The biomaterials studied in the included articles were carbomer hydrogel, micronized dermal graft tissue, crosslinked HA, HA with gelatine hydrogel, CaHA, carboxymethylcellulose (CMC), bovine collagen, micronized alloderm (Cymetra) (Lifecell Corp, Branchburg, NJ, USA), HA gel, carboxylic and hydroxylic multi-walled functionalized carbon, unequal particle sized middle viscosity and low viscosity HA, Rofilan (Laborata es Filorga, Lisbonne, Paris, France),Radiesse (Merz, Franksville, WI, USA),Restylane (Galderma Laboratories, Fort Worth, TX, USA), dextran beads in HA microsphere (MP), polyethylene glycol-diamine (PEG) microparticles, gelatine methacrylate MP, HA methacrylate, semi-IPN MP, glycol chitosan hydrogel, pluronic F127 with collagen, HA with poly(ethylene glycol) diacrylate (PEGDA) crosslinkers, silk protein based in HA suspension, resilin-like-polypeptide hydrogel, PEG30 hydrogel and polydimethylsiloxane (PDMS) with polydopamine (PDA).…”

“…To further identify suitable biomaterials, in vitro studies must include evaluations to elucidate the cellular response when integrated with the biomaterials. In vitro outcomes measured in this review included cell adhesion [ 43 ], cell viability/compatibility [ 37 , 39 , 50 ], cell phenotyping [ 49 ] and production of cytokines [ 49 ]. Among the types of cell used were human vocal fold fibroblasts (HVFF), NIH/3T3 cells, macrophages, vocal fold fibroblasts (VFF), Hacat cells and mouse NIH-3T3 embryonic fibroblasts.…”

“…However, Fu and co-researchers compared cell viability between the sets and control to quantify the cytotoxicity level of the biomaterials [ 39 ]. An interesting in vitro study by Coburn and co-researchers quantified the response of macrophages when cultivated with hydrogel and vocal fold fibroblasts [ 49 ]. The results are summarized in Table 4 .…”

“…However, the anti-inflammatory cytokine, IL-10 could have the potential to dampen the inflammation [ 71 ]. Nevertheless, this review shows that only a single study has explained inflammatory responses when developing biomaterials [ 49 ]. This test is suggested to be included for future research to elucidate molecular mechanisms of inflammation when a novel biomaterial is developed for tissue regeneration.…”

Tissue Engineering for Mimics and Modulations of Immune Functions

“…utilized a mix of carbodiimide, neomycin trisulfate, and pentagalloyl glucose as a substitute for glutaraldehyde to crosslink porcine aortic valve leaflet ECM for enhanced biocompatibility and resistance to enzymatic degradation. [ 131 ] Glyoxal, another dialdehyde crosslinker similar to glutaraldehyde, [ 138,139 ] was believed to be less cytotoxic than glutaraldehyde. For example, Browe et al.…”