ABSTRACT
Access to detailed information on cells loaded with nanoparticles with nanoscale precision is of a long-standing interest in many areas of nanomedicine. In this context, designing a single experiment able to provide statistical mean data from a large number of living unsectioned cells concerning information on the nanoparticle size and aggregation inside cell endosomes and accurate nanoparticle cell up-take is of paramount importance. Small-angle X-ray scattering (SAXS) is presented here as a tool to achieve such relevant data. Experiments were carried out in cultures of B16F0 murine melanoma and A549 human lung adenocarcinoma cell lines loaded with various iron oxide nanostructures displaying distinctive structural characteristics. Five systems of water-dispersible magnetic nanoparticles (MNP) of different size, polydispersity and morphology were analyzed, namely, nearly monodisperse MNP with 11 and 13 nm mean size coated with meso-2,3-dimercaptosuccinic acid, more polydisperse 6 nm colloids coated with citric acid and two nanoflowers (NF) systems of 24 and 27 nm in size resulting from the aggregation of 8 nm MNP. Up-take was determined for each system using B16F0 cells. Here we show that SAXS pattern provides high resolution information on nanoparticles disposition inside endosomes of the cytoplasm through the structure factor analysis, on nanoparticles size and dispersity after their incorporation by the cell and on up-take quantification from the extrapolation of the intensity in absolute scale to null scattering vector. We also report on the cell culture preparation to reach sensitivity for the observation of MNP inside cell endosomes using high brightness SAXS synchrotron source. Our results show that SAXS can become a valuable tool for analyzing MNP in cells and tissues.
Subject(s)
Magnetite Nanoparticles , Animals , Humans , Magnetics , Mice , Scattering, Small Angle , X-Ray Diffraction , X-RaysABSTRACT
Magnetic hyperthermia is an oncological therapy where magnetic nanostructures, under a radiofrequency field, act as heat transducers increasing tumour temperature and killing cancerous cells. Nanostructure heating efficiency depends both on the field conditions and on the nanostructure properties and mobility inside the tumour. Such nanostructures are often incorrectly bench-marketed in the colloidal state and using field settings far off from the recommended therapeutic values. Here, we prepared nanoclusters composed of iron oxide magnetite nanoparticles crystallographically aligned and their specific absorption rate (SAR) values were calorimetrically determined in physiological fluids, agarose-gel-phantoms and ex vivo tumours extracted from mice challenged with B16-F0 melanoma cells. A portable, multipurpose applicator using medical field settings; 100 kHz and 9.3 kA m-1, was developed and the results were fully analysed in terms of nanoclusters' structural and magnetic properties. A careful evaluation of the nanoclusters' heating capacity in the three milieus clearly indicates that the SAR values of fluid suspensions or agarose-gel-phantoms are not adequate to predict the real tissue temperature increase or the dosage needed to heat a tumour. Our results show that besides nanostructure mobility, perfusion and local thermoregulation, the nanostructure distribution inside the tumour plays a key role in effective heating. A suppression of the magnetic material effective heating efficiency appears in tumour tissue. In fact, dosage had to be increased considerably, from the SAR values predicted from fluid or agarose, to achieve the desired temperature increase. These results represent an important contribution towards the design of more efficient nanostructures and towards the clinical translation of hyperthermia.
Subject(s)
Ferrosoferric Oxide/chemistry , Hyperthermia, Induced , Melanoma, Experimental/therapy , Nanoparticles/chemistry , Sepharose/chemistry , Animals , Cell Line, Tumor , Cell Survival/drug effects , Colloids/chemistry , Cryoelectron Microscopy , Female , Magnetics , Melanoma, Experimental/diagnosis , Melanoma, Experimental/diagnostic imaging , Mice , Mice, Inbred C57BL , Monte Carlo Method , Nanoparticles/metabolism , Nanoparticles/toxicity , Phantoms, Imaging , TemperatureABSTRACT
El traumatismo encéfalo craneano (TEC) es un problema de salud de distribución mundial, y es especialmente prevalente en la población adulta joven. Es característica la presencia de uno o más focos de daño, que luego progresan hacia áreas inicialmente no lesionadas, mediante cascadas de respuesta inflamatoria, excitotoxicidad, condiciones de falla energética, y la participación de la glía amplificando la respuesta tisular al daño inicial. Esta progresión es, en teoría, susceptible de una intervención terapéutica. Sin embargo, hasta ahora todos los estudios con fármacos neuroprotectores han fracasado, no existiendo un tratamiento especí-fico efectivo. Los resultados negativos se explican en parte por el empleo de una estrategia centrada solo en las neuronas, sin considerar otras células participantes, u otros mecanismos patogénicos. Para cambiar este panorama, es necesario re-enfocar el problema a través de una mejor comprensión de los mecanismos que determinan la progresión del daño. En esta revisión discutiremos los principales mecanismos biológicos involucrados en la progresión del daño tisular post-trauma. Se aborda la fisiopatología general de los tipos de traumatismos, mecanismos celulares del daño secundario incluyendo inflamación, apoptosis, tumefacción celular, excitoxicidad, y participación de la glía en la propagación del daño. Se destaca el papel de laglía en cada uno de los mecanismos celulares mencionados. Se incluyen algunas aproximaciones terapéuticas relacionadas con los mecanismos descritos. Se finaliza con un diagrama general que resume los principales aspectos discutido (AU)
Traumatic brain injury (TBI) is a worldwide health problem that is especially prevalent in young adults. It is characterized by one or more primary injury foci, with secondary spread to initially not compromised areas via cascades of inflammatory response, excitotoxicity, energy failure conditions, and amplification of the original tissue injury by glia. In theory, such progression of injury should be amenable to management. However, all neuroprotective drug trials have failed, and specific treatments remain lacking. These negative results can be explained by a neuron centered approach, excluding the participation of other cell types and pathogenic mechanisms. To change this situation, it is necessary to secure a better understanding of the biological mechanisms determining damage progression or spread. We discuss the biological mechanisms involved in the progression of post-trauma tissue damage, including the general physiopathology of TBI and cellular mechanisms of secondary damage such as inflammation, apoptosis, cell tumefaction, excitotoxicity, and the role of glia in damage propagation. We highlight the role of glia in each cellular mechanism discussed. Therapeutic approaches related to the described mechanisms have been included. The discussion is completed with a working model showing the convergence of the main topics (AU)
Subject(s)
Humans , Craniocerebral Trauma/physiopathology , Brain Injury, Chronic/physiopathology , Apoptosis , Neurotoxins/pharmacokinetics , Neuroglia , Risk Factors , Disease ProgressionABSTRACT
Traumatic brain injury (TBI) is a worldwide health problem that is especially prevalent in young adults. It is characterized by one or more primary injury foci, with secondary spread to initially not compromised areas via cascades of inflammatory response, excitotoxicity, energy failure conditions, and amplification of the original tissue injury by glia. In theory, such progression of injury should be amenable to management. However, all neuroprotective drug trials have failed, and specific treatments remain lacking. These negative results can be explained by a neuron centered approach, excluding the participation of other cell types and pathogenic mechanisms. To change this situation, it is necessary to secure a better understanding of the biological mechanisms determining damage progression or spread. We discuss the biological mechanisms involved in the progression of post-trauma tissue damage, including the general physiopathology of TBI and cellular mechanisms of secondary damage such as inflammation, apoptosis, cell tumefaction, excitotoxicity, and the role of glia in damage propagation. We highlight the role of glia in each cellular mechanism discussed. Therapeutic approaches related to the described mechanisms have been included. The discussion is completed with a working model showing the convergence of the main topics.
