Ricerc@Sapienza

Silver nanoparticles capped with 3-mercapto-1propanesulfonic acid sodium salt (AgNPs-3MPS), able to interact with Ni2+or Co2+, have been prepared to detect these heavy metal ions in water. This system works as an optical sensor and it is based on the change of the intensity and shape of optical absorption peak due to the surface plasmon resonance (SPR) when the AgNPs-3MPS are in presence of metals ions in a water solution. We obtain a specific sensitivity to Ni2+and Co2+up to 500 ppb (part per billion).

In this work commercially available bifunctional organic dithiols, 4,4?-dithiol-biphenyl (BI), 4,4?-dithiolterphenyl (TR) and the on purpose prepared precursor of 4,4?-dithiol-trans-stilbene (ST), have been used for the stabilization of gold and silver nanoparticles (AuNPs and AgNPs). The bifunctional thiols have been chosen with different conjugation length, to prepare interconnected system of nanoparticles in order to achieve a tuning of their optical properties.

One of the main problems in the development of immunosensors is to overcome the complexity of binding antibody to the sensor surface. Most of immobilizing methods lead to a random orientation of antibodies with a lower binding site density and immunoaffinity. In order to control the orientation of antibody immobilization, several resorc[4]arene derivatives were designed and synthesized.