Luciana Dini

Glycans coated silver nanoparticles induces autophagy and necrosis in HeLa cells

This study reports the induction of autophagy by two concentrations (2×103 or 2×104 NPs/cell) of 30u2005nm sized β-D-Glucose- and β-D-Glucose/Sucrose-coated silver NanoParticles (AgNPs-G and AgNPs-GS respectively) in HeLa cells treated for 6, 12, 24 and 48 hrs. Cell viability was assessed by Neutral Red (NR) test and morphological evaluation. In addition ROS generation (NBT test) and induction of apoptosis/necrosis (Annexin V/Propidium Iodide-Annexin V/PI staining) and autophagy (Monodansylcadaverine-MDC staining) were evaluated. Cytotoxicity, ROS generation and morphology changes depend on NPs type and amount, and incubation time. As a general result, AgNPs-G are more toxic than AgNPs-GS. Moreover, the lowest AgNPs-GS concentration is ineffective on cell viability and ROS generation. Only 10% and 25% of viable HeLa cells were found at the end of incubation time in the presence of higher amount of AgNPs - G and AgNPs-GS respectively and in parallel ROS generation is induced. To elucidate the type of cell death, Annexin V/PI and MDC staining was performed. Interestingly, irrespective of coating type and NPs amount the percentage of apoptotic cells (Annexin V+/PI−) is similar to viable HeLa cells. At contrary, we observed a NPs amount dependent autophagy and necrosis induction. In fact, the lower amount of NPs induces autophagy (MDC+/PI− cells) whereas the higher one induces necrosis (Annexin V+/PI+ cells). Our findings suggest that AgNPs-induced cytotoxicity depends on AgNPs amount and type and provide preliminary evidence of induction of autophagy in HeLa cells cultured in the presence of AgNPs.This study reports the induction of autophagy by two concentrations (2×103 or 2×104 NPs/cell) of 30u2005nm sized β-D-Glucose- and β-D-Glucose/Sucrose-coated silver NanoParticles (AgNPs-G and AgNPs-GS respectively) in HeLa cells treated for 6, 12, 24 and 48 hrs. Cell viability was assessed by Neutral Red (NR) test and morphological evaluation. In addition ROS generation (NBT test) and induction of apoptosis/necrosis (Annexin V/Propidium Iodide-Annexin V/PI staining) and autophagy (Monodansylcadaverine-MDC staining) were evaluated. Cytotoxicity, ROS generation and morphology changes depend on NPs type and amount, and incubation time. As a general result, AgNPs-G are more toxic than AgNPs-GS. Moreover, the lowest AgNPs-GS concentration is ineffective on cell viability and ROS generation. Only 10% and 25% of viable HeLa cells were found at the end of incubation time in the presence of higher amount of AgNPs - G and AgNPs-GS respectively and in parallel ROS generation is induced. To elucidate the type of cell deat...

Cytotoxicity of β-D-glucose/sucrose-coated silver nanoparticles depends on cell type, nanoparticles concentration and time of incubation

The use of silver NanoParticles (AgNPs) in several consumer commercialized products, like food contact materials, medical devices and cosmetics has increased significantly, owing to their antibacterial and antifungal properties. Even though the NPs are widely diffused, due to the great variety in size, coating or shape, controversial data on their possible detrimental health effects still exist. Herein, by performing an easy and fast green method synthesis, we used β-D-glucose/sucrose to stabilize AgNPs and avoid the release of cytotoxic soluble silver ions Ag+ in the culture medium. The cytotoxic effects of these β-D-Glucose/Sucrose-Coated AgNPs (AgNPs-GS) was assessed on two cell culture models, which are human liver HepG2 and human Peripheral Blood Lymphocytes (PBLs) cells. AgNPs-GS, as determined by Transmission Electron Microscopy (TEM) analyses, had an average diameter of 30±5u2005nm, a spherical shape and were well-dispersed in the freshly-prepared solution. In addition, they were found spectrophotomet...

In vitro comparative study of the effects of silver and gold nanoparticles exploitable in the context of photodynamic therapy

The studies about therapeutic applications of gold (AuNPs) and silver (AgNPs) NanoParticles, in conventional and non-conventional cancer therapies are gaining increased attention. PhotoDynamic Therapy (PDT) consists in the use of photosensitizers (PSs), which upon accumulation in tumor cells cause the death of malignant cells after irradiation with light. PDT respect conventional chemotherapy has minimal systemic toxicity since PSs possess high selectivity to cancer cells. In PDT, AuNPs and AgNPs can be used to enhance singlet oxygen (1O2) production from PSs by exploiting surface plasmon resonance phenomenon based on the interaction of the conduction electrons of metal nanostructures with incoming light. AuNPs are highly stable and biocompatible; conversely, AgNPs could release Ag+ ions. To avoid this, we use glucose as capping agents. The maximum absorption peak of AgNPs and AuNPs is at 420 and 530u2005nm, respectively. These peaks coincide with light wavelengths used in our previous works to excite Rose Bengal (RB) in HeLa cells. Our results highlight the potentiality of such nanostructures in PDT: both NPs enter HeLa cells, colocalize with RB and induce toxic effects upon green light irradiation. In particular, the presence of AuNPs and AgNPs enhance the 1O2. Moreover, the antiproliferative effect of AgNPs alone corroborates the possibility to synergize the toxic effects of PDT treatment against cancer cells.The studies about therapeutic applications of gold (AuNPs) and silver (AgNPs) NanoParticles, in conventional and non-conventional cancer therapies are gaining increased attention. PhotoDynamic Therapy (PDT) consists in the use of photosensitizers (PSs), which upon accumulation in tumor cells cause the death of malignant cells after irradiation with light. PDT respect conventional chemotherapy has minimal systemic toxicity since PSs possess high selectivity to cancer cells. In PDT, AuNPs and AgNPs can be used to enhance singlet oxygen (1O2) production from PSs by exploiting surface plasmon resonance phenomenon based on the interaction of the conduction electrons of metal nanostructures with incoming light. AuNPs are highly stable and biocompatible; conversely, AgNPs could release Ag+ ions. To avoid this, we use glucose as capping agents. The maximum absorption peak of AgNPs and AuNPs is at 420 and 530u2005nm, respectively. These peaks coincide with light wavelengths used in our previous works to excite Rose Be...