RESUMEN
Despite undeniable advances in medicine in recent decades, cancer is still one of the main challenges faced by scientists and professionals in the health sciences as it remains one of the world's most devastating diseases with millions of fatalities and new cases every year. Thus, in this work, we endeavored to synthesize and characterize novel multifunctional immunoconjugates composed of quantum dots (QDs) as the fluorescent inorganic core and antibody-modified polysaccharide as the organic shell, focusing on their potential applications for in vitro diagnosis of non-Hodgkin lymphoma (NHL) cancer tumors. Chitosan was covalently conjugated with anti-CD20 polyclonal antibody (pAbCD20) via formation of amide bonds between amines and carboxyl groups. In the sequence, these biopolymer-antibody immunoconjugates were utilized as direct capping ligands for biofunctionalization of CdS QDs (CdS/chitosan-pAbCD20) using a single-step process in aqueous medium at room temperature. The nanostructures were characterized by UV-vis spectroscopy, photoluminescence spectroscopy (PL), FTIR, and transmission electron microscopy (TEM) with selected area electron diffraction. The TEM images associated with the UV-vis optical absorption results indicated formation of ultrasmall nanocrystals with average diameters in the range of 2.5-3.0 nm. Also, the PL results demonstrated that the immunoconjugates exhibited "green" fluorescent activity under ultraviolet excitation. Moreover, using in vitro laser light scattering immunoassay (LIA), the QDs/immunoconjugates have shown binding affinity against antigen CD20 (aCD20) expressed by lymphocyte-B cancer cells. In summary, innovative fluorescent nanoimmunoconjugate templates were developed with promising perspectives to be used in the future for detection and imaging of cancer tumors.
Asunto(s)
Anticuerpos Antineoplásicos , Antígenos CD20/metabolismo , Biomarcadores de Tumor/metabolismo , Quitosano , Linfoma de Células B , Imagen Óptica/métodos , Puntos Cuánticos/química , Anticuerpos Antineoplásicos/química , Anticuerpos Antineoplásicos/farmacología , Antígenos CD20/química , Linfocitos B/metabolismo , Linfocitos B/patología , Biomarcadores de Tumor/química , Línea Celular Tumoral , Quitosano/química , Quitosano/farmacología , Humanos , Linfoma de Células B/metabolismo , Linfoma de Células B/patologíaRESUMEN
The radiolabelled monoclonal antibody anti-CD20 has the property of binding to the CD20 antigen expressed on the cell surface of B-lymphocytes, thus making it a useful tool in the treatment of non-Hodgkin's lymphoma. In this work, the event-by-event Monte Carlo code NOREC is used to calculate the single-event distribution function f(1)(z) in the cell nucleus using the beta spectra of the (188)Re and (131)I radionuclides. The simulated geometry consists of two concentric spheres representing the nucleus and the cell surface embedded in a semi-infinite water medium. An isotropic point source was placed on the cell surface to simulate the binding of the anti-CD20 labelled with either (188)Re or (131)I. The simulations were carried out for two combinations of cell surface and nucleus radii. A method was devised that allows one to calculate the contribution of betas of energy greater than 1 MeV, which cannot be simulated by the NOREC code, to the single-event distribution function. It is shown that disregarding this contribution leads to an overestimation of the frequency-mean specific energy of the order of 9-12%. In general, the antibody radiolabelled with (131)I produces single-event distribution functions that yield higher frequency-mean specific energies.