Fluorescence Sensing of Tryptamine Using 5-Aminofluorescein Functionalized Gold Nanoparticles

This work describes the development of a fluorescence sensor based on citrate-reduced gold nanoparticles (GNPs) conjugated with 5-aminofluorescein (5AF) using EDC/NHS chemistry to create GNP@5AF nanoparticles. These nanoparticles were used to detect tryptamine (TRYP) by measuring changes in fluorescence intensity upon incubation with various TRYP concentrations. The sensor showed efficient fluorescence quenching with good linearity and a detection limit of 4 ng TRYP. The sensor’s applicability was tested in biological and food samples. In cheese and banana samples, a linear fluorescence enhancement allowed quantitative determination of TRYP within certain concentration ranges (2–10 ng in cheese and 2–16 ng in banana). However, nonlinear responses in other matrices limited the method’s broader application. Interference studies indicated that GNP@5AF had a high selectivity for TRYP compared to other amine-containing molecules. Overall, the GNP@5AF sensor offers a simple and sensitive fluorescence-based method for detecting tryptamine, with potential for food safety monitoring. The study suggests that further optimization with selective ligands could improve sensor performance and analytical robustness.

1. T. T. Trang, T. T. H. Pham, N. V. Dang, P. T. Nga, M. V. Linh, X. H. Vu, RSC Adv., 14, 9538–9546 (2024), doi: 10.1039/D4RA00575A.

2. Aruna, V. P. Verma, A. P. Singh, R. Shrivastava, J. Mol. Struct., 1295, 136549 (2024), doi: 10.1016/j.molstruc.2023.136549.

3. K. N. Patterson, M. A. Romero-Reyes, J. M. Heemstra, ACS Omega, 7, No. 37, 33046–33053 (2022), doi: 10.1021/acsomega.2c03085.

4. R. Singh, S. P. Srinivas, M. Kumawat, H. K. Daima, OpenNano, 15, 100194 (2024), doi: 10.1016/j.onano.2023.100194.

5. R. Ding, E. Frei, M. Fardanesh, H. H. Schrenk, P. Kremer, W. E. Haefeli, J. Clin. Pharmacol., 51, No. 5, 672–678 (2011).

6. S. Ngernpimai, T. Puangmali, A. Kopwitthaya, P. Tippayawat, A. Chompoosor, S. Teerasong, ACS Appl. Nano Mater., 7, No. 11, 13124–13133 (2024), doi: 10.1021/acsanm.4c01631.

7. F. F. E. Kohle, J. A. Hinckley, U. B. Wiesner, J. Phys. Chem. C, 123, No. 15, 9813–9823 (2019), doi: 10.1021/acs.jpcc.9b00297.

8. C. Ayala-Orozco, J. G. Liu, M. W. Knight, Y. Wang, J. K. Day, P. Nordlander, et al., Nano Lett., 14, No. 5, 2926–2933 (2014), doi: 10.1021/nl501027j.

9. V. Kiran, A. Thirumalai, P. Durgadevi, N. Akhtar, A. D. Prabhu, K. Girigoswami, et al., J. Colloid Interface Sci., 10, No. 1, 4 (2026).

10. P. Pallavi, K. Girigoswami, K. Harini, P. Gowtham, A. Thirumalai, A. Girigoswami, Naunyn Schmiedebergs Arch. Pharmacol., 398, No. 1, 867–880 (2025), doi: 10.1007/s00210-024-03321-2.

11. N. Hasanova, S. E. Çelik, R. Apak, Food Comp. Anal., 114, 104837 (2022), doi: 10.1016/j.jfca.2022.104837.

12. M. Gao, S. Li, Y. Lin, Y. Geng, X. Ling, L. Wang, et al., ACS Sens., 1, No. 2, 179–184 (2016), doi: 10.1021/acssensors.5b00182.

13. D. J. E. Costa, A. M. Martínez, W. F. Ribeiro, K. M. Bichinho, M. S. Di Nezio, M. F. Pistonesi, et al., Talanta, 154, 134–140 (2016), doi: 10.1016/j.talanta.2016.03.063.

14. N. Malini, S. Murugesan, A. Siva, Biosens. Nanotechnology, 245–266 (2023).

15. S. Narayan, A. Rajagopalan, J. S. Reddy, A. Chadha, RSC Adv., 4, No. 3, 1412–1420 (2014), doi: 10.1039/C3RA45887C.

16. H. Li, X. Wei, Y. Zhang, Y. Xu, K. Lu, C. Li, et al., J. Alloys Compd., 685, 820–827 (2016), doi: https://doi.org/10.1016/j.jallcom.2016.06.119.

17. H. Ma, Z. Li, N. Xue, Z. Cheng, X. Miao, Microchim. Acta, 185, No. 2, 93 (2018), doi: 10.1007/s00604-017-2633-1.

18. J. Huang, F. Li, R. Guo, Y. Chen, Z. Wang, C. Zhao, et al., Microchim. Acta, 185, No. 5, 260 (2018), doi: 10.1007/s00604-018-2798-2.

19. A. C. Manetta, L. Di Giuseppe, M. Giammarco, I. Fusaro, A. Simonella, A. Gramenzi, et al., J. Chromatogr. A, 1083, No. 1, 219–222 (2005), doi: 10.1016/j.chroma.2005.06.039.

20. C. del Mar Verde Méndez, M. P. Forster, M. Á. Rodríguez-Delgado, E. M. Rodríguez-Rodríguez, C. Díaz Romero, Eur. Food Res. Technol., 217, No. 4, 287–290 (2003), doi: 10.1007/s00217-003-0762-8.

21. Y. Ito, Y. Ikai, H. Oka, J. Hayakawa, T. Kagami, J. Chromatogr. A, 810, No. 1, 81–87 (1998), doi: 10.1016/S0021-9673(98)00185-X.

22. C. J. Haglock-Adler, A. Hurley, F. G. Strathmann, Clin. Biochem., 47, No. 15, 80–82 (2014), doi: 10.1016/j.clinbiochem.2014.07.008.

23. A. H. A. Hassan, L. Sappia, S. L. Moura, F. H. M. Ali, W. A. Moselhy, Md. P. T. Sotomayor, et al., Talanta, 194, 997–1004 (2019), doi: 10.1016/j.talanta.2018.10.066.

24. A. Serag, M. A. Algarni, A. A. Abd Al Maksoud, F. T. Alsulami, E. S. Alatwi, S. I. Alaqel, et al., J. Photochem. Photobiol. A Chem., 471, 116730 (2026), doi: 10.1016/j.jphotochem.2025.116730.

25. R. Raghav, S. Srivastava, Biosens. Bioelectron., 78, 396–403 (2016), doi: 10.1016/j.bios.2015.11.066.

26. Y. Yu, S. Ye, Z. Sun, J. You, W. Li, Y. Song, et al., RSC Adv., 12, No. 54, 35260–35269 (2022), doi: 10.1039/d2ra05037d.

27. L. Pang, T. Zhang, Y. Liu, D. Li, J. Li, M. Guan, et al. Sens. Actuator B-Chem., 391, 134061 (2023), doi: 10.1016/j.snb.2023.134061.

28. A. C. Morosanu, D. G. Dimitriu, D. O. Dorohoi, J. Mol. Struct., 1180, 723–732 (2019), doi: 10.1016/j.molstruc.2018.12.057.

29. M. Iosin, P. Baldeck, S. Astilean, Nucl. Instrum. Methods Phys. Res. B, 267, No. 2, 403–405 (2009), doi: 10.1016/j.nimb.2008.10.055.

30. P. V. Kumar, B. G. Singh, N. Maiti, M. Iwaoka, K. Indira Priyadarsini, J. Colloid Interface Sci., 436, 179–185 (2014), doi: 10.1016/j.jcis.2014.08.062.

31. K. A. Kang, J. Wang, J. B. Jasinski, S. Achilefu, J. Nanobiotechnology, 9, No. 1, 16 (2011), doi: 10.1186/1477-3155-9-16.

32. M. Swierczewska, S. Lee, X. Chen, Phys. Chem. Chem. Phys., 13, No. 21, 9929–9941 (2011), doi: 10.1039/C0CP02967J.

33. I. Fratoddi, A. Cartoni, I. Venditti, D. Catone, P. O’Keeffe, A. Paladini, et al., J. Colloid Interface Sci., 513, 10–19 (2018), doi: 10.1016/j.jcis.2017.11.010.

34. M. H. Mohd-Zahid, S. N. Zulkifli, C. A. Che Abdullah, J. Lim, S. Fakurazi, K. K. Wong, et al., RSC Adv., 11, No. 26, 16131–16141 (2021), doi: 10.1039/D1RA01093J.

35. S. K. Ghosh, A. Pal, S. Kundu, S. Nath, T. Pal, Chem. Phys. Lett., 395, No. 4, 366–372 (2004), doi: 10.1016/j.cplett.2004.08.016.

36. P. Luliński, M. Bamburowicz-Klimkowska, M. Dana, D. Maciejewska, J. Sep. Sci., 40, No. 8, 1824–1833 (2017), doi: 10.1002/jssc.201601349.

37. B. Redruello, D. Arranz, B. Szekeres, B. del Rio, M. A. Alvarez, Food Chem., 460, 140622 (2024), doi: 10.1016/j.foodchem.2024.140622.

38. M. Schüller, T. A.-P. McQuade, M. S.-S. Bergh, S. Pedersen-Bjergaard, E. L. Øiestad, Talanta Open., 7, 100171 (2023), doi: 10.1016/j.talo.2022.100171.

39. F. R. Franzen, H. Gross, Nature, 206, 1052 (1965), doi: 10.1038/2061052a0.

40. J. Islam, H. Shirakawa, T. K. Nguyen, H. Aso, M. Komai, Food Biosci., 13, 56–59 (2016), doi: 10.1016/j.fbio.2015.12.006.