Polymeric nanoparticles (NPs) are widely used for drug delivery applications due to high biodegradability, low toxicity and high loading capacity. The focus of this study is the development of photosensitizer Photosens (PS) loaded albumin NPs for efficient photodynamic therapy (PDT). To fabricate PS-loaded bovine serum albumin nanoparticles (BSA-PS NPs), we used a coacervation method with glutaraldehyde followed by passive loading of PS. Successful loading of PS was confirmed by appearance of characteristic peak in absorption spectrum which allows to determine the PS loading in BSA NPs. The synthesized BSA-PS NPs demonstrated low toxicity to HeLa cells at therapeutic concentrations of loaded PS. Compared to free PS solution, the synthesized BSA-PS NPs generated the singlet oxygen more effectively under laser irradiation at 660 nm. In addition, due to presence of various chemical groups on the surface of BSA-PS NPs, they are capable to adsorb on cell surface and accumulate in cells due to cellular uptake mechanisms. Owing to combination of PD and cell uptake advantages, BSA-PS NPs demonstrated higher efficacy of photodynamic damage to cancer cells as compared to free PS at equivalent concentrations. These results suggest that non-targeted BSA-PS NPs with high PD activity and low-fabrication costs of are promising candidates for transfer to PD clinic treatments.
Gold nanoshells are promising nanoparticles for biomedical applications such as biosensing, photothermal therapy, and surface enhanced Raman scattering. However, existing synthesis protocols produce polydisperse samples with extinction plasmonic spectrum much broader than that predicted by electromagnetic Mie simulations. Here we report on improved synthesis of gold nanoshells using monodisperse silica cores with very narrow size distributions of separated samples. As a result we were able to fabricate high quality silica/gold nanoshells with very narrow plasmon resonance peak, which is in good agreement with Mie calculations based on polydisperse TEM models. TEM images revealed a presence of dimers and trimers in as-prepared nonseparated samples. We performed extensive finite difference time-domain (FDTD) simulations to show that the plasmonic response of aggregated nanoshells results in enhanced extinction across NIR spectral band and in a minor broadening of the main plasmonic peak. To summarize, the improved synthetic technology produces high quality monodisperse silica/gold nanoshells which optical properties are in excellent agreement with electromagnetic simulations based on TEM size distributions.
Plasmon-resonant nanoparticles attached to cell membranes, under laser treatment can temporarily increase membrane permeability. In this paper, the influence of continuous-wave and pulsed (nanosecond) laser irradiation on living cells incubated with gold nanoparticles was investigated. Gold nanospheres, nanostars, and nanorods with different functionalization were used as plasmonic agents. The dependence between increase of medium temperature on the irradiation time was showed for nanostars and nanorods with different surface properties. Cells samples incubated with gold nanorods showed the highest temperature increase. Feasibility of cell optoporation by the use of gold nanospheres with variable functionalization was demonstrated. The cell membrane permeability was successfully enhanced as shown by the uptake of the fluorescent dye upon nanosecond laser treatment. Toxicity of the nanoparticles was estimated by MTT assay.