Date of Publication
11-2024
Document Type
Master's Thesis
Degree Name
Master of Science in Chemistry
Subject Categories
Chemistry
College
College of Science
Department/Unit
Chemistry
Thesis Advisor
Drexel H. Camacho
Abstract/Summary
Carbon dots have gained tremendous attention for applications in the biomedical field as they exhibit excellent biocompatibility, higher brightness, lower toxicity, and superior photostability. These promising carbon nanomaterials have found their application in the biomedical field, such as the detection of ions and organic compounds, drug delivery, and cell imaging. Carbon dots are usually prepared from any materials that contain mainly carbon, such as small molecule organic compounds and biomass/agricultural by-products. In efforts to minimize environmental pollution and to promote the sustainable and green synthesis of carbon dots, biomass, and agricultural wastes/by-products have been utilized and valorized to produce biocompatible and functional carbon dots materials. However, most of the carbon dots prepared from biomass and agricultural wastes/by-products have relatively poor fluorescence properties such as low fluorescence intensity and low quantum yield. In efforts to promote sustainability and a green approach to preparing nanomaterials, this study has developed carbon dots from waste Pili nutshells doped with group 5A elements, particularly N, P, and never-been-used As through facile hydrothermal method producing undoped, N-doped, P-doped, N/P-doped and As-doped carbon dots. The synthesized doped carbon dots have sizes less than 10 nm. The structure of carbon dots has exhibited (100), (102), and (002) lattice planes consistent with the graphitic structure of carbon dots with the measured lattice spacing of 0.336 nm for undoped carbon dots and a reduced lattice spacing of 0.323 nm, 0.324 nm, 0.326 nm, and 0.330 nm for N-doped, P-doped, N/P-doped and As-doped carbon dots, respectively. Various analytical techniques such as EDS, FTIR, UV-vis, and Zeta potential measurement have confirmed the successful doping of N, P, and As in carbon dots structure. The fluorescence scan of undoped carbon dots and doped carbon dots shows an emission wavelength of λem = 450 nm and an excitation wavelength of λem = 330- 8 350 nm. The quantum yield of undoped carbon dots is 1.66%, while the quantum yields of N-doped, P-doped, N/P-doped, and As-doped carbon dots are 4.04%, 4.03%, 3.72%, and 3.13%, respectively, showing the quantum yield enhancement of carbon dots through doping with N, P, and As. Biocompatibility investigation of doped carbon dots through PrestoBlue assay shows that undoped, N-doped, P-doped, N/P-doped, and As-doped carbon dots show low cytotoxicity with Vero cells and MCF-7 cells, indicating the good biocompatibility of doped carbon dots with normal and cancer cell lines. The prepared carbon dots were used as fluorescent probes for the cell imaging of Vero cells through confocal laser scanning microscopy. Cell imaging investigation on Vero cells shows majority of fluorescence is observed in the cytoplasmic region and minimal fluorescence in the nucleus which indicates that carbon dots penetrated the cells and accumulated mainly in the cytoplasm with minimal penetration in the nucleus. This development of doped carbon dots from waste Pili nutshells shows the opportunity to develop functional nanomaterials while minimizing the environmental impact of thrown wastes through the valorization of biomass and agricultural wastes/by-products into various functional nanomaterials.
Abstract Format
html
Language
English
Format
Electronic
Keywords
fluorescence; Canarium; Biocompatibility
Recommended Citation
Macaspag, C. M. (2024). Fluorescent carbon dots from pili nut shells (Canarium ovatum Engl) doped with group 5A element for cell biocompatibility and imaging. Retrieved from https://animorepository.dlsu.edu.ph/etdm_chem/25
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Embargo Period
12-10-2027
