Publication
Superparamagnetic Iron oxide “nanozymes” for cancer theranostics
| Summary: | Cancer is the second most prevalent cause of death worldwide. Chemotherapy and ra- diotherapy are some of the most commonly used treatments. They, however, present serious side effects for the patient. As technology evolves, new possibilities for cancer treatment arise. In this sense, cancer theranostics provides the possibility of having diagnosis and treatment in a single system, improving patient care, and providing personalized cancer treatment methods. One of the most promising approaches to theranostics is using superparamagnetic iron oxide nanoparticles (SPIONs) as they can be used as contrast agents in magnetic reso- nance imaging and in magnetic hyperthermia due to the increase of their bulk temperature and of their surroundings when an external alternating magnetic field is applied. More re- cently, it was discovered that SPIONs mimic peroxidase and catalase enzymatic activities. The first one contributes to direct tumour elimination by generating toxic radicals while the latter converts hydrogen peroxide into water and oxygen, helping overcome the hypoxia present in tumour tissues. In this work, SPIONs were coated with dimercaptosuccinic acid and 3-amino-propyltri- ethoxysilane and characterized. The peroxidase and catalase enzyme-like activity of coated SPIONs was also evaluated as well as the influence that various pH and different hydrogen peroxide concentrations have on the enzymatic-like activity. After this characterization, cyto- toxic assays were performed using the SaOs-2 cell line with SPIONs and hydrogen peroxide to determine which are the cytotoxic concentrations for both. The main goal was to assess the in-vitro catalase-like behaviour of SPIONs in normoxia and hypoxia environments. Lastly, the SPIONs were submitted to an alternating magnetic field and hyperthermic temperatures were reached. Here, we showed that SPIONs possess intrinsic catalase and peroxidase like activities, however the same was not achieved in in-vitro studies. In this sense, more studies are required to accurately assess catalase-like activity in vitro, as well as more in-depth magnetic hyper- thermia assays including in-vitro to better understand SPIONs as theranostics system. |
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| Main Authors: | Mateus, Marta Vilar Saraiva |
| Subject: | Cancer Catalase IONzymes Magnetic hyperthermia Peroxidase Superparamag- netic nanoparticles |
| Year: | 2022 |
| Country: | Portugal |
| Document type: | master thesis |
| Access type: | open access |
| Associated institution: | Universidade Nova de Lisboa |
| Language: | English |
| Origin: | Repositório Institucional da UNL |
| Summary: | Cancer is the second most prevalent cause of death worldwide. Chemotherapy and ra- diotherapy are some of the most commonly used treatments. They, however, present serious side effects for the patient. As technology evolves, new possibilities for cancer treatment arise. In this sense, cancer theranostics provides the possibility of having diagnosis and treatment in a single system, improving patient care, and providing personalized cancer treatment methods. One of the most promising approaches to theranostics is using superparamagnetic iron oxide nanoparticles (SPIONs) as they can be used as contrast agents in magnetic reso- nance imaging and in magnetic hyperthermia due to the increase of their bulk temperature and of their surroundings when an external alternating magnetic field is applied. More re- cently, it was discovered that SPIONs mimic peroxidase and catalase enzymatic activities. The first one contributes to direct tumour elimination by generating toxic radicals while the latter converts hydrogen peroxide into water and oxygen, helping overcome the hypoxia present in tumour tissues. In this work, SPIONs were coated with dimercaptosuccinic acid and 3-amino-propyltri- ethoxysilane and characterized. The peroxidase and catalase enzyme-like activity of coated SPIONs was also evaluated as well as the influence that various pH and different hydrogen peroxide concentrations have on the enzymatic-like activity. After this characterization, cyto- toxic assays were performed using the SaOs-2 cell line with SPIONs and hydrogen peroxide to determine which are the cytotoxic concentrations for both. The main goal was to assess the in-vitro catalase-like behaviour of SPIONs in normoxia and hypoxia environments. Lastly, the SPIONs were submitted to an alternating magnetic field and hyperthermic temperatures were reached. Here, we showed that SPIONs possess intrinsic catalase and peroxidase like activities, however the same was not achieved in in-vitro studies. In this sense, more studies are required to accurately assess catalase-like activity in vitro, as well as more in-depth magnetic hyper- thermia assays including in-vitro to better understand SPIONs as theranostics system. |
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