Caratterizzazione e comportamento citotossicologico di argento nanoparticellare

The aim of the research was to develop and validate an analytical method for the determination of silver ion and to discriminate it from the total silver, in a certified material of colloidal silver (NM-300K Silver <20 nm provided by the Joint Research Centre ) and in two samples of colloidal silver which differ in the diameter of the particles. For this objective, the analysis technique is exploited in flow, "Flow Injection Analysis" (FIA), coupled to a spectrophotometric detection. Was also carried out a characterization of nanoparticles of silver present in the sample certificate and the two samples of solid colloidal silver through the use of TEM and BET. Were also conducted measurements of zeta potential regard to the sample certificate. The certified material and two samples of silver particle were evaluated in a developmental toxicity study on human cells. The method mentioned before is eligible for the purpose and it is also very simple and quick to perform. Therefore, it represents an alternative method and is operationally more convenient to be adopted with respect to those already present in the literature that are economically disadvantageous compared to the FIA. The values of average RSD% in the whole range of concentrations investigated appear to be below 3% for the 3 matrices analyzed, which thereby ensure a good accuracy. The relevant concentrations of Ag+ found in the matrices analyzed have allowed me to say that the preparation of products containing only colloidal silver turns out to be problematic. According to the results of the physico-chemical characterization of 'NM-300K, it can be noted that: ¿ there is a typical crystal structure icosahedral silver; ¿ there are not perfectly uniform particle sizes between them, in order to indicate the possible presence of small aggregates of size above 20 nm; this is confirmed by the analysis of the zeta potential from which, moreover, it is possible to affirm that the colloidal solution is unstable. According to the results of the physical-chemical characterization of the two samples of silver particle it can be stated that: ¿ in the 1st sample macro aggregates are larger than 50 nm which demonstrates the instability of this colloid; ¿ in the 2nd sample there is an equal distribution of the particles which but do not have a crystal structure for the silver classical icosahedral particle; ¿ the values of surface area obtained for both samples are typical for this type of materials. The results obtained from citotossicological analysis conducted on human cells allow me to say that the certified material, with equal dilutions, is found to be more cytotoxic than the two samples of silver particle. The cytotoxicity is attributable to the silver ion prensent in the two samples of silver particle.