Elsevier

Journal of Surgical Research

Volume 251, July 2020, Pages 254-261
Journal of Surgical Research

Pediatric/Congenital/Developmental
Functionalization of PTFE Materials Using a Combination of Polydopamine and Platelet-Rich Fibrin

https://doi.org/10.1016/j.jss.2019.11.014Get rights and content

Abstract

Background

The diaphragm, which forms a physical barrier between the thoracic and the abdominal cavities, is also the major part of the respiratory system. Congenital diaphragmatic hernia (CDH) is a malformation of that partition muscle. Expanded polytetrafluoroethylene (e-PTFE), a synthetic nondegradable biomaterial, is currently used for the repair of diaphragm defects. Indeed, this hydrophobic biomaterial does not promote rapid and dense cell colonization. Surface modifications are needed to favor or even guide cellular responses.

Materials and methods

In this context, we present here a practical and effective way of functionalization of the e-PTFE material. We investigated, by using electron microscopy, the coating with PRF (Platelet-Rich Fibrin) of PDA (Polydopamine) treated e-PTFE implant material.

Results

We demonstrate that this straightforward chemical functionalization with PDA increases the hydrophilicity of e-PTFE and thus improves tissue integration. Then, we demonstrated that whatever the contact time between PRF and e-PTFE and the centrifugation speed, the PDA coating on the e-PTFE biomaterial promotes further biological events like cell adhesion and spreading.

Conclusions

Our findings clearly show that this composite coating (chemically by using PDA + biologically by using PRF) method of e-PTFE is a simple, interesting and promising way to favor tissular integration of such biomaterials.

Introduction

The diaphragm, which forms a physical barrier between the thoracic and the abdominal cavities, is also the major muscle of the respiratory system. Congenital diaphragmatic hernia (CDH) is a malformation of that partition muscle. Its incidence rate oscillates around 1 per 2500 births.1 CDH requires surgical treatment for closing the diaphragm defect. Over the last decades, several biomaterials have been proposed to close diaphragmatic defects: synthetic nonabsorbable types (a composite mesh of PTFE associated with polypropylene, polymeric silicone for instance) or natural absorbable types (Surgisis-porcine small intestinal submucosa or Permacol-porcine dermal collagen e.g.), that demonstrated no advantages compared to PTFE.2,3 Even if some biomaterials are available and quite satisfactory for the treatment of CDH, some optimizations are welcome owing to the specifications required for a prosthesis. The used biomaterial has to be biocompatible, long-lasting, and elastic. Still, it is quite difficult to find a biomaterial that fits all these requirements. Therefore, nonelastic patches of expanded polytetrafluoroethylene (e-PTFE), a synthetic nondegradable biomaterial, are currently used for the repair of diaphragm defects.4

Polytetrafluoroethylene (PTFE), is a thermoplastic polymer of tetrafluoroethylene [(CF2-CF2)n] discovered fortuitously in 1938 by Plunkett for the Du Pont de Nemours company.5 It has a very high thermal and chemical stability, a low coefficient of friction and high hydrophobicity. The stretched form of PTFE (expanded PTFE or e-PTFE) was developed by Wilbert Gore in 1976.6 The stretching process was performed at temperatures higher than the lowest crystalline melting point of PTFE to obtain a more porous material than the original one. The first medical application of PTFE consisted of the designing of artificial heart valves.7 Gradually the field of application has expanded with the development of vascular grafts, bone regeneration supports, and prosthesis for hernia repair. e-PTFE has thus proved to be very interesting in the surgical field due to its biocompatibility and stability over time. In these applications, e-PFTE is used as a barrier.8 Indeed it is a rigid hydrophobic material that does not make it an ideal candidate for rapid and dense cell colonization. Much work has been done to modify the surface of the e-PTFE as the surface of a material is the first contact area for the host cells. Specific surface modifications would, therefore, make it possible to modify or even guide cellular responses. The most commonly used method for PTFE surface modification involves high energy radiation. The adsorption of hydrophobic molecules has also been explored. Among the molecules tested, catecholamine groups inspired by mussel byssus (e.g., L-3,4-dihydroxyphenylalanine, DOPA) seem particularly interesting because of their strong affinity to a wide variety of substrate.9,10 The oxidation of dopamine leads to polydopamine, a material closely related to the eumelanin of the skin.

Polydopamine (PDA) was first used as a surface coating agent in 2007. Its functional groups are many and varied, such as catechol, amines, and quinones, which constitute a versatile coating agent for any organic or inorganic support. In addition, it possesses coordination sites for metal cations and quinone moieties able to react with nucleophiles like the amino (-NH2) or sulfhydryl (-SH) groups present in proteins. It, thus, favors the secondary functionalization by molecules supporting cell colonization on inert materials in the raw state.11

On the other hand, platelet-rich fibrin or PRF is a platelet concentrate obtained after centrifugation of whole blood without anticoagulation agents. It is a three-dimensional network of fibrin rich in platelets, leukocytes and growth factors.12

PRF has a great heterogeneity, between each of us and between each individual. Its composition varies greatly depending on the parameters of centrifugation. But many studies show that, despite this variability, it constitutes significant support for tissue regeneration and the wound healing process.13 To our knowledge, PRF has still not been used to promote the healing process on diaphragm but is currently used in oral or maxillofacial surgery. It, therefore, seems highly beneficial to optimize cellular colonization of e-PTFE by the use of PRF. However, given the hydrophobic (and lipophobic) characteristics of PTFE, we undertook to evaluate the contribution of an underlayer of polydopamine on PTFE to promote the linkage of PRF elements to the biomaterial while waiting for colonization by the host-cells. The purpose of these investigations, conducted by electron microscopy, is to compare and to characterize the deposition of PRF on PTFE treated or not with polydopamine. These assessments are thought to be the first step of the original research about a combined chemical and biological functionalization of e-PTFE for medical applications. The functionalization of e-PTFE with polydopamine and PRF is not expected to change the mechanical properties of the used membrane but to increase its interactions with adhering cells.

Section snippets

Biomaterial functionalization

e-PTFE samples provided from Gore (Dualmesh W.L. Gore and Associates, Flagstaff, AZ) were sterilized using the STERRAD process (low-temperature hydrogen peroxide plasma gas technology) and then conditioned in 1 cm2 samples. Dopamine hydrochloride was purchased from Sigma–Aldrich (Saint Louis, MO, ref. H8502) and used without further purification. Dopamine hydrochloride at a concentration of 2 mg mL−1 was dissolved in 50 mM Tris buffer (pH = 8.5) with dissolved oxygen as the oxidant.

Results

The e-PTFE of interest is characterized by two distinct faces, a smooth one which is supposed to limit tissue integration and a porous and “textured” one that is aimed to promote cell colonization and tissue integration. Microscopy studies were performed on both sides of the material with essentially identical observations. For didactic concerns and to give a clear picture, pictures and micrographs will only be taken on the less complex smooth face observed in electron microscopy.

First of all,

Discussion

Bridging a tissue defect and guiding tissue regrowth is a major challenge in the field of biomaterials. In the majority of clinical referral centers, e-PTFE prostheses continue to be favored for the surgical repair of congenital diaphragmatic hernia.1 Even though collective experience has demonstrated that CDH outcome depends on patient factors, as hernia side and presence of associated anomalies,16 but also rests on the biological host responses. Indeed, the rapid growth of the child that

Conclusions

Finally, the present study shows that whatever the contact time between PRF and e-PTFE and the centrifugation speed, the PDA coating on the e-PTFE biomaterial promotes further biological events. The use of liquid PRF produces a denser fibrin matrix remaining in contact with the e-PTFE substrate after rinsing. It must be pointed out that these findings are constant, whatever the donor, the centrifugation speed, and the PRF area (fibrin matrix or buffy coat). Clearly, this composite coating

Statement of financial support

No financial assistance was received in support of the Study.

Acknowledgment

We thank FIMATHO association for its financial support to our research.

Author contribution: Contributions to conception and design, acquisition of data, or analysis and interpretation of data: I Talon, J Hemmerle. Drafting the article or revising it critically for important intellectual content; and Final approval of the version to be published: A Schneider and V Ball.

References (29)

  • I. Talon et al.

    Polydopamine functionalization: a smart and efficient way to improve host responses to e-PTFE implants

    Front Chem

    (2019)
  • A.F. Chandler-Temple et al.

    Expanded poly (tetrafluoroethylene): from conception to biomedical device

    Chem Aust

    (2008)
  • R.Y. Kannan et al.

    Current status of prosthetic bypass grafts: a review

    J Biomed Mater Res B Appl Biomater

    (2005)
  • A.I. Cassady et al.

    Enhancing expanded poly (tetrafluoroethylene) (e-PTFE) for biomaterials applications

    J Appl Polym Sci

    (2014)
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