| Zugriffsnummer | 55809 |
| Dokumenttyp | Zeitschriftenartikel |
| Peer Review | mit Peer Review |
| Sprache | Englisch |
| Titel | Do cell culturing influence the radiosensitizing effect of gold nanoparticles: scrutinizing recent evidence |
| Autor(in); Institution |
Mkanda, Oswald Msosa; University Dar es Salaam, Dar es Salaam, TANZANIA; Mzuzu University, Mzuzu, MALAWI
|
| Quelle/Jahr | Radiation Physics and Chemistry: 240 (2026), 1 - 15 |
| Artikelnummer | 113466 |
| ISSN | 0969-806X (print) ; 1879-0895 (online) |
| DOI | |
| Verlag | Amsterdam [u.a.]: Pergamon Press, Elsevier |
| Freie Schlagworte | gold nanoparticles ; Monte Carlo simulation ; data quality ; secondary particle equilibrium ; local effect model ; PTB high performance compute cluster |
| Zusammenfassung | In radiobiological experiments, the cells can either float in suspension or adhere to the walls of the sample holder. When irradiation is performed in the presence of dose modifying agents such as gold nanoparticles (AuNPs), the different shapes of the floating or adherent cells may imply a different dose to the nucleus, with biological consequences such as cell survival. In a recent simulation study based on voxelized cell models, differences of up to a factor of 2 were found between the predicted survival of floating and adherent cells or cells oriented differently with respect to the incident beam. These results and the methodology to obtain them are examined in this paper. It is shown that the reported orientation dependence can be explained by the fact that the simulation setup corresponds to the case of cells in the dose build-up region near the surface. The biases introduced by the simulation setup and by the use of voxelized geometry in conjunction with the local effect model (LEM) for cell survival are quantified. The results show that simulated irradiation of a cell near the surface with an incident beam matched to the cell dimensions results in dose values that are by a factor of about 50 lower than the dose to cells deeper in the medium when irradiated with a 60Co spectrum and lateral beam dimensions in the centimeter range. Furthermore, the number of ionizing photon interactions in gold nanoparticles in a cell near the surface is lower by a factor of about 2. Using the average dose in voxels of dimensions in the order of 0.2 µm for the assessment of cell survival according to the LEM leads to an underestimation of the number of lesions from AuNPs undergoing an ionizing interaction by one to two orders of magnitude and thus to an overestimation of cell survival. The analysis further shows that the reported step-like changes between the survival predicted from the mean dose and the LEM could be explained by the fact that in the entire simulation only in one event an ionizing interaction of a photon took place in an AuNP. It is shown that the probability of this is in the permille range and that the total number of electrons leaving an AuNP, estimated from the reported electron spectrum, is three orders of magnitude higher than the value estimated from the expectation of photon interactions in the AuNPs. This suggests further hidden biases in the simulation geometry, for example, if the distribution of AuNPs was non-uniform. Finally, the effect of cell geometry on the predicted survival rate was examined for approximate cell geometries and 100 kV x-ray irradiation, for which the probability of photon interaction in gold nanoparticles is by more than two orders of magnitude higher than for 60Co irradiation. The results show that the effects are negligible for 5 nm nanoparticles at the concentration considered in preceding work. For 50 nm nanoparticles and thus a thousand times higher mass fraction of gold, significant reduction in cell survival is found, with a clear additional reduction predicted by the LEM as compared to the prediction based on mean dose to the nucleus. |
| Themenbereich der Metrologie | Metrologie in der Medizin |
| Förderinformationen (1) |
Förderername: German Academic Exchange Service
Förderer ID: 0000 0004 0550 0389 Förderer ID Typ: ISNI Förderungsnummer: DAAD 91897204 |