Carbon dots: synthesis via hydrothermal carbonization from protein sources and their interaction with biological systems

Author(s)

Liz Specian de Moraes

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Química
• Defense date: 2016-08-26

Examining board members

Oswaldo Luiz Alves; Adley Forti Rubira; Juliano Alves Bonacin

• Advisor: Oswaldo Luiz Alves

Abstract

Nanotechnology has drawn the interest of Science and Industry due to the wide range of materials and applications that can be developed from nanoscale systems. Recently, carbon dots (CDs) have emerged as a new class of carbon-based nanomaterials with interesting photoluminescent properties that enable their potential use in bioimaging, sensing and drug delivery applications. Due to their low toxicity and biocompatibility, CDs have been considered as a promising alternative to conventional semiconductor-based quantum dots. In this work, we report the use of bovine serum albumin (BSA) and bovine plasma (PB) as precursors to synthesis of CDs via hydrothermal carbonization. In addition, the study also includes the detailed physical-chemical characterization and the evaluation of interaction between these nanomaterials and biological systems, applying hemolytic and cell internalization assays. The morphology and size of the carbon nanoparticles were analyzed by Transmission Electronic Microscopy. CDs obtained from BSA and PB had spherical shape with an average size of 8.7 and 3.7 nm, respectively. The fluorescence quantum yield was calculated using quinine sulfate as reference. CDs synthesized from BSA and PB exhibited quantum yields of 4.9% and 3.8%, when they were excited at wavelength of 315 and 300 nm, respectively. Furthermore, the red shift phenomenon was observed in the emission spectra of both synthesized CDs, indicating the formation of particles with different sizes or the presence of surface energy traps distribution. The composition of CDs was determined by Elemental Analysis and X-ray Photoelectron Spectroscopy. Both nanomaterials contained C, N, O and S elements. The hemolytic assay demonstrated the synthesized CDs did not cause damage to red blood cell membrane at concentrations between 5 and 250 ?g.mL-1. The cellular internalization of these nanomaterials in Chinese hamster ovary cells and macrophages was confirmed by Confocal Laser Scanning Microscopy technique (AU)

• FAPESP's process: 14/23302-5 - Carbon dots: synthesis via hydrothermal carbonization from renewable sources and their interaction with biological systems
• Grantee: Liz Specian de Moraes
• Support Opportunities: Scholarships in Brazil - Master