2023-2025
Graphene derivatives with a hierarchical architecture for analytical chemistry and nanomedicine
Various graphene derivatives (G) such as graphene oxide (GO) and
graphene nanoparticles (GQDs) are one of the hottest research topics in
recent years. These derivatives became the basis for the next research
step - the development of hierarchical architectures such as porous
graphene (GMP), graphene sponge (GNS), GQDs with immobilized metal
nanoparticles, etc. In recent years our team has been working with
graphene derivatives and managed to advance in 0D nanoparticles that
showed excellent activity in the membranes of electrochemical sensors.
In this project 2D and 3D manometric hierarchical architectures will be
investigated. In the search for materials that can increase the
sensitivity of electrochemical sensors, GMP and GNS will be immobilized
on the electrode surface. Due to the hierarchical and porous
electroactive structure nanomaterials can increase sensitivity and will
improve sensor selectivity. The sensors will be evaluated in the
analysis of critical environmental contaminants such as pesticides and
endocrine disruptors, as well as clinically essential chemicals such as
neurotransmitters and glucose. Hybrid materials, obtained by
immobilizing 0D nanoparticles on the surface of inorganic supports, will
be studied as adsorbents. GQDs and GMP nanosheets capable of forming a
porous nano-capsule and, therefore, their ability to act as drug
carriers like Doxorubicin and Cisplatin will be studied. In this project
antiviral activity of boron and nitrogen doped GQDs will be studied
against RNA and DNA viruses (enveloped and non-enveloped), for example
influenza A, coxsackievirus A, human herpesvirus 1 and adenovirus 4.
Antibacterial activity against Escherichia coli and Staphylococcus
aureus of Doped GQDs will also be researched. The hierarchical
architectures type GQDs with immobilized metal nanoparticles will be
studied in the photodynamic therapy of cancer cells of U87, SH-SY5Y and
T98G lines.
2021-2024
Chromatography methods with mass spectrometric and fluorescence detector
to determine the content of polycyclic aromatic hydrocarbons in lipid
samples
Os hidrocarbonetos policíclicos aromáticos (PAHs) são poluentes orgânicos persistentes. Devido à sua natureza lipofílica, os PAHs podem contaminar facilmente óleos, mamíferos e organismos marinhos. Os adsorventes hidrofóbicos são amplamente usados para descontaminar fontes de água com PAHs. Infelizmente, tais adsorventes são inúteis para a purificação de óleos, combustíveis e outras soluções lipídicas, uma vez que os adsorventes não têm seletividade para PAHs e, portanto, serão saturados por componentes da matriz hidrofóbica. Os adsorventes de natureza hidrofílica com alta afinidade para os PAHs são necessários para a recuperação seletiva desses poluentes da matriz hidrofóbica. Recentemente, demonstramos que pontos quânticos de óxido de grafeno (GOQDs) são capazes de se ligar firmemente aos PAHs, devido às interações extramoleculares pi-pi. Esse efeito pode levar a um novo tipo de adsorvente seletivo de PAHs, que é capaz de descontaminar soluções lipídicas. Propriedades de adsorventes à base GOQDs como adsorventes serão estudadas com métodos de cromatografia GC-MS e HPLC-FL para determinar o teor de hidrocarbonetos aromáticos policíclicos em amostras lipídicas.
2019-2021
Nanodiamonds with immobilized carbon quantum dots as new nanomaterials for theranostics
Among the
most promising application of nanoparticles are medicine and
biotechnology. In these areas nanomaterials have been used for drug
delivery, photodynamic and photothermal therapies, for theranostics.
Till today nanomaterials that most commonly used for biomedical
application are: metals (Au, Ag, Pt), metal oxides (SiO2, TiO2)
and carbon-based materials (carbon nanotubes, fullerene, graphene).
However, the biomedical application of known nanomaterials is quite
limited due to eventual cytotoxicity and low colloidal stability.
Therefore, the importance of development of novel nanoparticles is
generally recognized. Among the new candidates, carbon-based structures
attract a lot of attention because of their biocompatibility, high
surface area and stability. Among them nanodiamonds (NDs) and carbon
quantum dots (CQDs) are recognized as a new candidate for
nanobiotechnological applications.
The
idea of the research is to combine attractive properties of NDs in
biotechnology and medicine (low cytotoxicity, easy metabolization,
ability to penetrate cells and leave the cell without damaging the
membrane) with attractive properties for medical diagnosis of CQDs
(strong and stable photoluminescence). Combination of these two
nanomaterials can also give synergistic effect of stabilization of the
hybrid objects in physiological solution (because of strong
carboxylation of the CNDs surface that negatively charge the particles
in basic media). Immobilization of the CQDs on NDs surface can also
increase the surface area of the particles and their ability for further
chemical functionalization.
This research is focused on the elaboration and
investigation of new hybrid NDs-based nanomaterials with covalently
immobilized CQDs (NDs@CQDs) and their application in theranostics and in
photodynamic therapy of cancer. To enable the particles utilization in
sonodynamic therapy mixed-particle composite will be prepared with TiO2
nanoparticles (TiO2@CQDs). Additionally, covalent
immobilization of photosensitizer and bioactive components on the
surface of nanocomposites via photo-cleavable linker is planned to
ensure their controlled release.
2018-2021
Doped SiO2/TiO2 nanocomposite for visualization, photodynamic and radiation therapy of cancer
The present proposal deals with the synthesis and characterization of nanocomposite materials for non-invasive therapy and visualization of tumors of different kind.
Due to growing trend of non-invasive treatment of tumor cells there are intensive studies in non-penetrating antineoplastic techniques related to in situ generation of active species that kill unwanted cellular objects. In most cases such active species are molecules of singlet oxygen. To generate reactive oxygen species (ROS) locally soft X-Ray and light (visible or near infrared, vis/NIR) irradiation are commonly used. Also there are some indications that ultrasound treatment can also generate ROS. An important limitation of such approach is permissibility of tissue for irradiation that enables treatment of surface-located cells.
This research project focuses on novel materials that can generate ROS under X-ray, NIR, and/or ultrasound treatment and, hence, overcome limitation of known photosensitizers that absorb light of the visible spectral regions above 700 nm. For generation of ROS in water media, it is proposed to use nanocrystals of TiO2 doped with lanthanides (Ln). In order increase efficiency of ROS generation, TiO2 will be immobilized into silica (SiO2) matrix that insures high surface area of SiO2/TiO2 material. At the same time, porous structure of SiO2/TiO2 nanocomposite allows further immobilization of ROS promoters such as methylene blue (MB) and carbon quantum dots (CQDs). Such hybrid doped titania/silica nanomaterials can generate ROS under X-ray or ultrasound treatment. Due to luminescence properties of CNDs and rare-earth dopants the localization of the particles can be monitored.
2015-2018
Adsorventes organo-minerais multifuncionais para sólida extração seletiva de compostos biologicamente importantes e sua análise com nano-UPLC-QToF
O projeto aqui apresentado propõe: 1) obter e estudar novos adsorventes para a pré-concentração para grupos-seletivos de biocompostos; 2) utilizar o adsorvente proposto para preparação de amostra de SPE e/ou SPME obtidas de produtos naturais visando a sua análise cromatográfica; 3) otimizar o cromatógrafo de nano-UPLC-QTOF-MS disponível no Departamento de Química da PUC-Rio para a análise química de produtos naturais e extratos com o adsorvente testado. Para a préconcentração seletiva dos compostos polifenólicos propomos adsorventes novos à base de sílica que contém grupos funcionais de carbazole (SiO2-CS), antracina (SiO2-Ant) e óxido de grafeno (SiO2-GO) covalentemente imobilizados na superfície de sílica. Estes compostos podem formar complexos com compostos bioativos, ter enriquecido e empobrecido pi-pi sistema. Ele irá proporcionar uma melhor seletividade para compostos selecionados do que os conhecidos.
|
ORCID