Chitin Nanofibril Application in Tympanic Membrane Scaffolds to Modulate Inflammatory and Immune Response

Serena Danti,Lorenzo Moroni,Giovanna Donnarumma,Bahareh Azimi,Alessandra Fusco,Stefano Berrettini,Stefano Linari,Shivesh Anand,Claudio Ricci,Andrea Lazzeri,Lorenzo Zavagna,Carlos Mota,Mario Milazzo

doi:10.3390/pharmaceutics13091440

Abstract

Chitin nanofibrils (CNs) are an emerging bio-based nanomaterial. Due to nanometric size and high crystallinity, CNs lose the allergenic features of chitin and interestingly acquire anti-inflammatory activity. Here we investigate the possible advantageous use of CNs in tympanic membrane (TM) scaffolds, as they are usually implanted inside highly inflamed tissue environment due to underlying infectious pathologies. In this study, the applications of CNs in TM scaffolds were twofold. A nanocomposite was used, consisting of poly(ethylene oxide terephthalate)/poly(butylene terephthalate) (PEOT/PBT) copolymer loaded with CN/polyethylene glycol (PEG) pre-composite at 50/50 (w/w %) weight ratio, and electrospun into fiber scaffolds, which were coated by CNs from crustacean or fungal sources via electrospray. The degradation behavior of the scaffolds was investigated during 4 months at 37 °C in an otitis-simulating fluid. In vitro tests were performed using cell types to mimic the eardrum, i.e., human mesenchymal stem cells (hMSCs) for connective, and human dermal keratinocytes (HaCaT cells) for epithelial tissues. HMSCs were able to colonize the scaffolds and produce collagen type I. The inflammatory response of HaCaT cells in contact with the CN-coated scaffolds was investigated, revealing a marked downregulation of the pro-inflammatory cytokines. CN-coated PEOT/PBT/(CN/PEG 50:50) scaffolds showed a significant indirect antimicrobial activity.

Highlights

Due to its peculiar anatomy and function, the ideal restoration of damaged tympanic membrane (TM) should fulfill several features, which can be critical to enabling an optimal performance, within an infectious and chronically inflamed tissue environment [1]
PEOT/PBT [6,8,10], we showed that its nanocomposite PEOT/PBT/(CN/polyethylene glycol (PEG) 50:50)
We investigated in vitro a putative role of Chitin nanofibrils (CNs) as anti-inflammatory agents to be employed in middle ear replacements

Summary

Introduction

Due to its peculiar anatomy and function, the ideal restoration of damaged tympanic membrane (TM) should fulfill several features, which can be critical to enabling an optimal performance, within an infectious and chronically inflamed tissue environment [1]. Chronic otitis media (COM) represents a major challenge in eardrum pathology, as it is characterized by a repeatedly infected and long term inflamed middle ear, prone to TM perforation [3,4]. Auto/allografts from other tissues are clinically used as patches or replacements to repair the eardrum. These have been shown to have suboptimal outcomes [5]. To fill this gap, nanotech manufactures, based on electrospinning and/or 3D printing approaches involving synthetic polymers, have recently been proposed as new routes for TM reconstruction under the tissue engineering paradigm [6,7,8]. By virtue of ultrafine fibers, scaffolds based on biodegradable polymers, like polycaprolactone (PCL) and poly(ethylene oxide terephthalate)/poly(butylene terephthalate) (PEOT/PBT), obtained via electrospinning, have demonstrated an efficient reepithelization in vitro by human TM keratinocytes, as well as colonization by human mesenchymal stem cell (hMSC)

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Conclusion