Initial Assessment of Dye Incorporation in Bombyx mori Silk Biomaterials

James Gu, Cindy Gu

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Keywords: Fluorescent silk, organic dyes, Bombyx mori, biosensors, biocompatible materials, dietary dye incorporation, silk fibroin

TL;DR: Feeding Bombyx mori silkworms fluorescent dyes like Rhodamine B and Sulforhodamine 101 can produce visibly fluorescent silk suitable for biosensing.

Abstract: This study presents a preliminary and environmentally sustainable method for producing fluorescent silk by incorporating fluorescent dyes directly into the diet of Bombyx mori silkworms. Five dye compounds—Fluorescein Sodium, Rhodamine B, Rhodamine 101 Inner Salt, Sulforhodamine 101, and Rhodamine 110 Chloride—were administered at a 0.1% concentration (0.02 g of dye per 20 g of mulberry chow) starting at the 2nd instar. Silk cocoons formed during the 5th instar were analyzed for fluorescence, mechanical strength, and structural consistency. Rhodamine B exhibited the highest fluorescence intensity, followed by Sulforhodamine 101, Rhodamine 101 Inner Salt, Fluorescein Sodium, and Rhodamine 110 Chloride. Tensile strength testing revealed the control group had the highest mechanical strength, with strength decreasing in the following order: Sulforhodamine 101, Rhodamine 101 Inner Salt, Rhodamine 110 Chloride, Fluorescein Sodium, and Rhodamine B. Optical microscopy showed uniform silk structure in the control group, semi-uniformity in Sulforhodamine 101, Rhodamine B, and Rhodamine 101 Inner Salt, with inconsistency in Rhodamine 110 Chloride and Fluorescein Sodium. This method of producing fluorescent silk eliminates the need for post-processing while preserving mechanical integrity and enabling stable long-term fluorescence. The resulting biocompatible silk materials hold strong potential in clinical biosensing applications, where implantable silk fibers serve as real-time monitors of disease markers, infection, or wound healing progression through visible fluorescence changes, offering a natural, safe, and flexible alternative for in vivo diagnostics and regenerative therapies.

Track: 2. Sensors and systems for digital health, wellness, and athletics

NominateReviewer: James Gu, [e-mail]

Submission Number: 135