Utility of Thermal Cross-Linking in Stabilizing Hydrogels with Beta-Tricalcium Phosphate and/or Epigallocatechin Gallate for Use in Bone Regeneration Therapy.

Beiyuan Gao,Yoichi Yamada,Yoshihiro Takeda,Yoshitomo Honda,Tomonari Tanaka,Shunsuke Baba,Takayuki Nambu

doi:10.3390/polym14010040

Beiyuan Gao, Yoichi Yamada + Show 5 more

Open Access

https://doi.org/10.3390/polym14010040

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Journal: Polymers	Publication Date: Dec 23, 2021
Citations: 2	License type: CC BY 4.0

Affiliation: Osaka Dental University, Kyoto Institute of Technology

Abstract

β-tricalcium phosphate (β-TCP) granules are commonly used materials in dentistry or orthopedic surgery. However, further improvements are required to raise the operability and bone-forming ability of β-TCP granules in a clinical setting. Recently, we developed epigallocatechin gallate (EGCG)-modified gelatin sponges as a novel biomaterial for bone regeneration. However, there is no study on using the above material for preparing hydrogel incorporating β-TCP granules. Here, we demonstrate that vacuum heating treatment induced thermal cross-linking in gelatin sponges modified with EGCG and incorporating β-TCP granules (vhEc-GS-β) so that the hydrogels prepared from vhEc-GS-β showed high stability, β-TCP granule retention, operability, and cytocompatibility. Additionally, microcomputed tomography morphometry revealed that the hydrogels from vhEc-GS-β had significantly higher bone-forming ability than β-TCP alone. Tartrate-resistant acid phosphatase staining demonstrated that the number of osteoclasts increased at three weeks in defects treated with the hydrogels from vhEc-GS-β compared with that around β-TCP alone. The overall results indicate that thermal cross-linking treatment for the preparation of sponges (precursor of hydrogels) can be a promising process to enhance the bone-forming ability. This insight should provide a basis for the development of novel materials with good operativity and bone-forming ability for bone regenerative medicine.

Highlights

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CharacterizationMoafcSrpoosncogpesic(Porbescuerrvsoartsioonf sHsyhdorowgeelds)no significant changes in the samples before after vacuum-heating treatment; Field emission scanning electron microscopy (FE-SEM) observations showed that the porous β-tricalcium phosphate (β-TCP) waethxfeteielslrpteeMrvnneaapcccecaaurprouoasfmstucigol-odweteahhnxplrteeaeeioipasltcdglpittrneioeeorinnnlenbcasgpcecsnaweseaatldsrrprloeeevassnrfastapueteig(tomolgpFieaonnlirlteignaegegnptupdseiitrbnsr;asoielFrhn(ceaeFE2eonadcisC-wgldhSslb,ueEeDasynsrdnMp)eea(g.ognFd2AenolioAdigbgfignitsus,enieBiebsrgrtg)relh(n.vettF2ehAiahificCetgcTehicr,uocRpDaayhnrnnu-s)eaFsgt.trraT2AesecalAhIhlwcfiRiotnta,neBeawnaerrtt)gnheie.tpzerhddeAahsoectTtXariihrcsonRRymhaen-sDttaFfehtotrraTdhearofleIieclmtsRuisthnapeumeamerβolintsrz-pispodnpTahlcuoCtetXaoishnsoPsnRegβenbfiDeef-efroovTsrfmr,floeoClettnromehsPhewduaeewaβlfithtsntnh-saepyTdgesrco-CoenPxngpfeeiersvrm,eitmnhe drogels were prepared by adding the pure water or medium in the following experiments
This study demonstrated that the introduction of a thermal cross-linking process during the preparation of gelatin hydrogels containing epigallocatechin gallate (EGCG) and β-TCP significantly enhanced the retention of β-TCP in the prepared hydrogels

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. In addition to the use of gelatin alone, the polymers had been fused with other components, such as epigallocatechin gallate (EGCG) [11] (an extract of green tea that exhibits anti-inflammatory [11], antibacterial [12], and antioxidant [13] effects), growth factors that control cell proliferation and differentiation [14], and various calcium phosphates [15] including β-TCP [16]. Gelatin for medical use—often obtained from bovine bone and pig skin [17]—has been shown to carry growth factors extract of green tea that exhibits anti-inflammatory [11], antibacterial [12], and antioxidant [13] effects), growth factors that control cell proliferation and differentiation [14], and various calcium phosphates [15] including β-TCP [16]. A part of these sponges was thermally cross-linked using the vacuum heating technique (right part of Figure 1)

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Discussion

Conclusion