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Tryptophan-Conjugated Carbon Dots with Enhanced Cellular Uptake as a Potential Drug Delivery System for Melanoma
Nasrin Imumkachi1, Pornpattra Rattanaseth1, Sawinee Ngernpimai2
1Department of Biochemistry, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.
Abstract:
Melanoma is a rare but highly aggressive form of skin cancer that can rapidly metastasize, leading to a significant mortality rate. A main challenge in chemotherapy is the lack of selectivity in drug delivery to tumor sites, which affects both tumor and healthy tissues. Developing drug delivery systems (DDS) capable of preferentially interacting with transporters expressed on cancer cells may help address this issue. Carbon dots (CDs) have emerged as promising tools for the advancement of DDS due to their distinctive fluorescent characteristics, good water solubility, biocompatibility, and straightforward fabrication. In this work, CDs were synthesized via a facile method and conjugated with tryptophan (Trp) to evaluate their potential application as a DDS in melanoma. The fabricated CDs were characterized for their size, surface charge, optical properties, functional groups, and elemental analysis. LAT1 expression was examined by immunofluorescence, confirming higher levels in SK-MEL-2 melanoma cells compared to HK-2 normal kidney cells. Biocompatibility was established before conjugating CDs with tryptophan (Trp), ditryptophan (di-Trp), and tritryptophan (tri-Trp) and assessing their size, functional groups, and optical characteristics. Cellular uptake studies showed preferential uptake of Trp-conjugated CDs in SK-MEL-2 cells over HK-2 cells, indicating that tri-Trp-CDs exhibited the highest uptake. Molecular dynamics simulations suggested potential CDs-LAT1 interactions via van der Waals and electrostatic interactions. Trp-conjugated CDs were biocompatible with both SK-MEL-2 and HK-2 cells and could be electrostatically loaded with doxorubicin (DOX), exhibiting enhanced cytotoxicity against SK-MEL-2 cells compared to DOX alone. A trend toward greater selectivity for SK-MEL-2 cells over normal cells was observed, with tri-Trp/DOX showing the most pronounced effect, possibly reflecting LAT1-1 mediated uptake. These findings suggest that Trp-modified CDs may serve as promising DDS candidates for melanoma treatment.
Insights
Tryptophan-conjugated carbon dots show promise as targeted drug delivery systems for melanoma. These novel systems enhance chemotherapy effectiveness and selectivity, potentially improving treatment outcomes for this aggressive skin cancer.
Area of Science:
- Biomaterials Science
- Nanotechnology
- Cancer Research
Background:
- Melanoma is an aggressive skin cancer with high mortality, often challenging to treat with chemotherapy due to lack of drug selectivity.
- Targeted drug delivery systems (DDS) that interact with cancer-specific transporters are needed to improve chemotherapy efficacy and reduce side effects.
- Carbon dots (CDs) offer unique properties like fluorescence and biocompatibility, making them suitable for advanced DDS applications.
Purpose of the Study:
- To synthesize and characterize tryptophan (Trp)-conjugated carbon dots (CDs) for potential use as a DDS in melanoma.
- To evaluate the selective cellular uptake of Trp-conjugated CDs by melanoma cells over normal cells.
- To assess the efficacy of Trp-conjugated CDs loaded with doxorubicin (DOX) for targeted melanoma treatment.
Main Methods:
- Carbon dots (CDs) were synthesized and characterized for physical and optical properties.
- Tryptophan (Trp), ditryptophan (di-Trp), and tritryptophan (tri-Trp) were conjugated to CDs.
- Cellular uptake studies were performed using SK-MEL-2 melanoma cells and HK-2 normal kidney cells.
- Molecular dynamics simulations were used to predict interactions between CDs and the LAT1 transporter.
- Doxorubicin (DOX) was loaded onto Trp-conjugated CDs, and cytotoxicity was evaluated.
Main Results:
- Tryptophan-conjugated CDs demonstrated preferential uptake by SK-MEL-2 melanoma cells compared to HK-2 normal cells, with tri-Trp-CDs showing the highest uptake.
- Molecular simulations indicated potential interactions between CDs and the LAT1 transporter.
- Trp-conjugated CDs loaded with doxorubicin (DOX) exhibited enhanced cytotoxicity against melanoma cells, with improved selectivity over normal cells.
- The tri-Trp/DOX combination showed the most significant effect, suggesting LAT1-mediated uptake.
Conclusions:
- Tryptophan-modified carbon dots show potential as targeted drug delivery systems for melanoma.
- The observed preferential uptake and enhanced cytotoxicity suggest LAT1-mediated targeting of melanoma cells.
- These Trp-conjugated CDs represent a promising strategy for developing more effective and selective melanoma therapies.
![Radiosynthesis of 1-2-[18F]Fluoroethyl-L-Tryptophan using a One-pot, Two-step Protocol](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F63025.jpg&w=3840&q=50)
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