Mulberry Leaves (Morus rubra)-Derived Blue-Emissive Carbon Dots Fed to Silkworms to Produce Augmented Silk Applicable for the Ratiometric Detection of Dopamine.

Silk fibers (SF) reeled from silkworms are constituted by natural proteins, and their characteristic structural features render them applicable as materials for textiles and packaging. Modification of SF with functional materials can facilitate their applications in additional areas. In this work, we report the preparation of functional SF embedded with carbon dots (CD) through the direct feeding of a CD-modified diet to silkworms. We obtained fluorescent and mechanically robust SF from silkworms (Bombyx mori) that were fed on CDs synthesized from the Morus rubra variant of mulberry leaves (MB-CDs). MB-CDs were introduced to silkworms from the third instar onwards by spraying them on the silkworm feed, the mulberry leaves. MB-CDs were synthesized hydrothermally without adding surface passivating agents and were observed to have a quantum yield of 22%. With sizes of ∼4 nm, MB-CDs exhibited blue fluorescence, and they can be used as efficient fluorophores to detect Dopamine (DA) up to the limit of 4.39 nM. The nanostructures and physical characteristics of SF weren't altered when the SF were infused with MB-CDs. Also, we demonstrate a novel DA sensing application based on fluorescence with the MB-CD incorporated SF. The MB-CD-embedded SF thus open up intriguing prospects for fluorescent micro-devices and fabrics. This article is protected by copyright. All rights reserved.