Recent Advances in Silk Sericin/Calcium Phosphate Biomaterials

Anabela Veiga,Fernando Rocha,Filipa Castro,Ana L Oliveira

doi:10.3389/fmats.2020.00024

Abstract

Calcium phosphates (CaPs) have been widely used in the field of biomedical engineering as bone graft substitutes or as carriers for drug delivery applications. Recent developments have focused on combining CaPs with proteins to obtain functional biomaterials that accommodate a broader spectrum of functional requirements. Silk sericin was considered an unutilized protein by-product from the textile industry, generating tons of residues every year. However, much effort has been dedicated to its recovery after being associated with numerous biological properties such as antioxidant, antibacterial, anti-coagulation and regenerative activities. Recently, sericin has also demonstrated to be suitable as a template for CaP mineralization. The present review focuses on the recent developments for the production of Sericin/CaP composites, exploring their potential applications in bioengineering and opening new avenues in other research fields such as in the cosmetic and food industries. In addition, this paper can also be useful as a guideline to design future research based on Sericin/CaP biomaterials.

Highlights

Bone matrix consists of both a non-mineralized organic component (∼20% of the wet weight) and a mineralized inorganic component (∼65–70%), composed mainly by collagen and carbonated calcium phosphate (CaP) crystals, respectively
In a quest to mimic bone tissue, several studies have focused on the synthesis of CaP composites using synthetic polymers [polyglycolic acid (PGA), poly L-lactic acid (PLLA), polylactic-coglycolic acid (PLGA), and polycaprolactone (PCL)] (Rezwan et al, 2006; Lee and Yuk, 2007; Chen et al, 2014), natural polymers (Pighinelli and Kucharska, 2013; Cardoso et al, 2014; Salama, 2019), proteins (Dias et al, 2010; Bleek and Taubert, 2013; Brown and Barker, 2014; Liu, 2015; Farokhi et al, 2018), Silk Sericin/Calcium Phosphate Biomaterials or combinations of the foregoing (Chen et al, 2014)
- Sericin extraction was performed in boiling water (105◦C, 1 h); Soaking method: - Cloths made of raw silk, normal silk fiber, and sericin films were soaked in 1.5 SBF

Summary

INTRODUCTION

Bone matrix consists of both a non-mineralized organic component (∼20% of the wet weight) and a mineralized inorganic component (∼65–70%), composed mainly by collagen and carbonated calcium phosphate (CaP) crystals, respectively. The use of sericin/CaP composites reduces the inherent environmental impact of sericin disposal and allows the development of new functional biomaterials This silk protein increases antioxidant, anti-tyrosinase and anti-inflammatory activity; stimulates collagen production, tumor inhibitory effects; induces the nucleation of bone-like CaPs; and promotes stability and prolonged release in drug delivery systems (Aramwit, 2014; Lamboni et al, 2015). Amino acids can highly influence the mineralization process of CaPs. Glutamic acid and aspartic acid play a critical role in controlling HAp nucleation and growth, by attracting calcium and phosphate ions and increasing the local supersaturation, which results in the development of crystals. The last requirement is not fulfilled by using only sericin (Ahsan et al, 2018)

Methodology

Findings

CONCLUSIONS