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

Abstract

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, the preparation of functional SF embedded with carbon dots (CD) is reported through the direct feeding of a CD‐modified diet to silkworms. Fluorescent and mechanically robust SF are obtained from silkworms (Bombyx mori) that are fed on CDs synthesized from the Morus rubra variant of mulberry leaves (MB‐CDs). MB‐CDs are introduced to silkworms from the third instar by spraying them on the silkworm feed, the mulberry leaves. MB‐CDs are synthesized hydrothermally without adding surface passivating agents and are 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 are infused with MB‐CDs. Also, a novel DA sensing application based on fluorescence with the MB‐CD incorporated SF is demonstrated.

Applications of Mulberry Leaves: An Overview

“…Mulberry leaves are used commercially in sericulture, since the silk producing insects (Bombyx mori) feed on leaves of mulberry plant at their caterpillar stage (Samami et al, 2019). Silkworms eat mulberry leaves to make cocoons, which is used to obtain silk fibers, and the leaf protein content is correlated with the cocoon production (Urbanek et al, 2022;John et al, 2023). Different amino acids (valine, threonine, methionine, phenylalanine, leucine, lysine, arginine and histidine) present in these leaves are essential for silkworm growth (Borah and Praban, 2020).…”