title: Water-soluble nanoconjugates of quantum dot-chitosan-antibody for in vitro detection of cancer cells based on "enzyme-free" fluoroimmunoassay.
abstract: Cancer remains one of the world's most devastating diseases with millions of fatalities and new cases every year. In this work, we attempted to develop a facile "enzyme-free" fluoroimmunoassay based on the novel nanoconjugates composed of CdS quantum dots (QDs) as the fluorescent inorganic core and an antibody-modified polysaccharide as the organic shell, modeling their possible application for the in vitro diagnosis of non-Hodgkin lymphoma (NHL) cancer. Chitosan was conjugated with an anti-CD20 polyclonal antibody (pAbCD20) by the formation of covalent amide bonds. In the sequence, these chitosan-antibody conjugates were utilized as direct ligands for the surface biofunctionalization of CdS QDs (CdS/chitosan-pAbCD20) using a single-step colloidal process in aqueous medium at room temperature. The most relevant physico-chemical properties of these nanoconjugates were assessed by morphological and spectroscopic techniques. The results indicated that CdS nanocrystals were produced with an average diameter of 2.5 nm and with cubic zinc blende crystalline nanostructure. The CdS-immunoconjugates (CdS/chitosan-pAbCD20) presented colloidal hydrodynamic diameter (HD) of 15.0 ± 1.2n m. In addition, the results evidenced that the "enzyme-free" QD-linked immunosorbent assay (QLISA) was effective for the in vitro detection against the antigen CD20 (aCD20) based on fluorescent behavior of the CdS nanoconjugates. Moreover, the CdS-immunoconjugates were successfully used for fluorescence bioimaging of NHL cancer cells. Finally, the cell viability results using different cell cultures based on LDH, MTT and Resazurin bio-assays have demonstrated no cytotoxicity of the new CdS-chitosan bioconjugates relative to the standard controls. Thus, CdS conjugates may offer a promising platform for the future development of in vitro and in vivo applications for the detection and diagnosis of NHL cancer cells.
authors.affiliation: Center of Nanoscience, Nanotechnology, and Innovation-CeNano(2)I, Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais, UFMG, Av. Presidente Antônio Carlos, 6627, Belo Horizonte, MG 31.270-901, Brazil. Electronic address: hmansur@demet.ufmg.br.
authors.forename: Herman S
authors.initials: HS
authors.lastname: Mansur
authors.affiliation: Center of Nanoscience, Nanotechnology, and Innovation-CeNano(2)I, Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais, UFMG, Av. Presidente Antônio Carlos, 6627, Belo Horizonte, MG 31.270-901, Brazil.
authors.forename: Alexandra A P
authors.initials: AA
authors.lastname: Mansur
authors.affiliation: Center of Nanoscience, Nanotechnology, and Innovation-CeNano(2)I, Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais, UFMG, Av. Presidente Antônio Carlos, 6627, Belo Horizonte, MG 31.270-901, Brazil; Department of Preventive Veterinary Medicine, Veterinary School, UFMG, Brazil.
authors.forename: Amanda
authors.initials: A
authors.lastname: Soriano-Araújo
authors.affiliation: Department of Preventive Veterinary Medicine, Veterinary School, UFMG, Brazil.
authors.forename: Zélia I P
authors.initials: ZI
authors.lastname: Lobato
authors.affiliation: Center of Nanoscience, Nanotechnology, and Innovation-CeNano(2)I, Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais, UFMG, Av. Presidente Antônio Carlos, 6627, Belo Horizonte, MG 31.270-901, Brazil; Department of Physiology and Biophysics, ICB, UFMG, Brazil.
authors.forename: Sandhra M
authors.initials: SM
authors.lastname: de Carvalho
authors.affiliation: Department of Physiology and Biophysics, ICB, UFMG, Brazil.
authors.forename: Maria de Fatima
authors.initials: Mde F
authors.lastname: Leite
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D048271:Chitosan / Q000737:chemistry*; D002522:Chlorocebus aethiops; D015200:Fluoroimmunoassay; D058726:Nanoconjugates / Q000009:adverse effects / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry; D036103:Nanotechnology; D045663:Quantum Dots; D014961:X-Ray Diffraction
chemical_list: D058726:Nanoconjugates; D048271:Chitosan
keywords: Bioconjugate; Nanomaterial; Nanomedicine; Nanoparticle; Nanotechnology; Quantum dot