# Biophysical properties and antimicrobial efficacy of a novel Silk Sericin Mineral Trioxide Aggregate

## TL;DR

A new dental material combining silk sericin and MTA was developed, showing improved antimicrobial properties for better root canal treatments.

## Contribution

The novel Silk Sericin-MTA conjugate is introduced as a promising endodontic biomaterial with enhanced antimicrobial efficacy.

## Key findings

- The Silk Sericin-MTA conjugate showed structural modifications confirmed by ATR-FTIR and circular dichroism.
- Silk Sericin exhibited the highest antimicrobial activity against tested oral pathogens compared to MTA and the conjugate.
- The conjugate displayed a non-uniform surface with shallow depressions, unlike the flat surface of MTA.

## Abstract

Mineral Trioxide Aggregate (MTA) is widely used in endodontics due to its excellent biocompatibility and sealing abilities. However, complete eradication of bacteria from the root canal remains challenging. Currently available materials cannot ensure a complete hermetic seal and antimicrobial properties, which are essential to prevent reinfection. This study aimed to develop a novel Mineral Trioxide Aggregate combined with silk sericin and to evaluate its biophysical properties and antimicrobial efficacy against oral pathogens.

Lyophilized silk sericin powder was mixed with MTA in a 1:1 ratio. Silk sericin-MTA Conjugate (SC), Silk sericin (SS), and MTA were evaluated for their biophysical properties using Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, x-Ray diffraction, atomic force microscopy, and circular dichroism. The antimicrobial efficacy was evaluated against Staphylococcus aureus, Enterococcus faecalis, and Candida albicans using MIC, MTT, and time kill assay.

ATR-FTIR spectroscopy revealed distinctive peaks, confirming the structural modifications of the Sericin-MTA conjugate. x-ray diffraction revealed that all groups exhibited a lattice structure and were found to be crystalline in nature. However, in atomic force microscopy, MTA appeared to have a flat and uniform surface, while Sericin-MTA conjugate showed shallow depressions across its surface. The circular dichroism revealed the typical properties of silk protein, which is mainly composed of α-helical structures in Sericin-MTA conjugate. The antimicrobial activity was observed in the order of MTA < SC < SS.

This research provides concrete evidence that the innovative combination of MTA and silk protein enhances antimicrobial efficacy, making it a promising biomaterial for use as a medicament in endodontic procedures.