Purpose: To analyse changes of cell inactivation and proliferation under therapeutic irradiation conditions along the proton spread out Bragg peak (SOBP) with particular emphasis on its distal declining edge. Materials and methods: HTB140 cells were irradiated at four positions: plateau, middle, distal end and distal declining edge of the 62 MeV proton SOBP. Doses ranged from 2–16 Gy. They were normalised in the middle of SOBP and delivered following the axial physical dose profile. Survival, proliferation and cell cycle were assessed seven days after irradiation. Results: Moving from proximal to distal irradiation position surviving fractions at 2 Gy (SF2) decreased from 0.88–0.59. Increased radiosensitivity of the cells was noticed for the doses below 4 Gy, resulting in two gradients of cell inactivation, stronger for lower and weaker for higher doses. Relative biological effectiveness (RBE) increased from 1.68–2.84 at the distal end of SOBP. A further rise of RBE reaching 7.14 was at its distal declining edge. Following the axial physical dose profile of SOBP the strongest inactivation was attained at its distal end and was comparable to that at its declining edge. Conclusions: Survival data confirmed very high radioresistance of HTB140 cells. An effect similar to low-dose hyper radiosensitivity (HRS) was observed for order of magnitude larger doses. Better response of cells to protons than to γ-rays was illustrated by rather high RBE. Strong killing ability at the SOBP distal declining edge was the consequence of increasing proton linear energy transfer.

Raman and AFM analyses represent a tool for the evaluation of cytotoxic and anti-proliferative effects in cells induced by CeO₂ nanoparticles.

The literature data emphasize that nanoparticles might improve the beneficial effects of near-infrared light (NIR) on wound healing. This study investigates the mechanisms of the synergistic wound healing potential of NIR light and silver metal–organic frameworks combined with nitrogen- and sulfur-doped carbon dots (AgMOFsN-CDs and AgMOFsS-CDs, respectively), which was conducted by testing the fibroblasts viability, scratch assays, biochemical analysis, and synchrotron-based Fourier transform infrared (SR-FTIR) cell spectroscopy and imaging. Our findings reveal that the combined treatment of AgMOFsN-CDs and NIR light significantly increases cell viability to nearly 150% and promotes cell proliferation, with reduced interleukin-1 levels, suggesting an anti-inflammatory response. SR-FTIR spectroscopy shows this combined treatment results in unique protein alterations, including increased α-helix structures and reduced cross-β. Additionally, protein synthesis was enhanced upon the combined treatment. The likely mechanism behind the observed changes is the charge-specific interaction of N-CDs from the AgMOFsN-CDs with proteins, enhanced by NIR light due to the nanocomposite’s optical characteristics. Remarkably, the complete wound closure in the in vitro scratch assay was achieved exclusively with the combined NIR and AgMOFsN-CDs treatment, demonstrating the promising application of combined AgMOFsN-CDs with NIR light photodynamic therapy in regenerative nanomedicine and tissue engineering.

Ionizing radiation induces DNA double strand breaks (DSBs) that trigger phosphorylation of the histone protein H2AX (γH2AX). Immunofluorescent staining visualizes formation of γH2AX foci, allowing their quantification. This method, as opposed to Western blot assay and Flow cytometry, provides more accurate analysis, by showing exact position and intensity of fluorescent signal in each single cell. In practice there are problems in quantification of γH2AX. This paper is based on two issues: the determination of which technique should be applied concerning the radiation dose, and how to analyze fluorescent microscopy images obtained by different microscopes. HTB140 melanoma cells were exposed to γ-rays, in the dose range from 1 to 16 Gy. Radiation effects on the DNA level were analyzed at different time intervals after irradiation by Western blot analysis and immunofluorescence microscopy. Immunochemically stained cells were visualized with two types of microscopes: AxioVision (Zeiss, Germany) microscope, comprising an ApoTome software, and AxioImagerA1 microscope (Zeiss, Germany). Obtained results show that the level of γH2AX is time and dose dependent. Immunofluorescence microscopy provided better detection of DSBs for lower irradiation doses, while Western blot analysis was more reliable for higher irradiation doses. AxioVision microscope containing ApoTome software was more suitable for the detection of γH2AX foci.