The use of nanomaterials for drug delivery, cell targeting and imaging is becoming more and more interesting because of the possibility to have many different kinds of probes that give us the opportunity to image cells or carry drugs in the body in a very specific way and for the exciting possibility to excrete such small materials very easily.
In our group we work on several different kinds of nanomaterials to be used as drug delivery systems or bio-imaging agents for cancer cells. Our principal aim in this framework is to obtain biocompatible materials with tunable properties and different chemical nature or functionalities to reach the target in a very specific way. In particular we prepare and functionalize mesoporous silica nanoparticles, zeolites, silicon nanoparticles (fig.1), cobalt nanoparticles with different sizes and properties. Later we test these materials in vitro and in vivo to study their uptake by cells and their toxicity. The nanomaterials that we prepare show different properties going from luminescent properties (intrinsic or due to the presence of a dye) to magnetic properties. The specific targeting can be reached both using materials that can be loaded with drugs that can be released upon the change of the environment or even simply chemically binding to the nanoprobes, the biomolecules of interest.
Fig. 1 (a) Epifluorescence image of mitosis of BV2 cells stained with Si NPs under blue light irradiation (b) and (c) confocal image of BV2 cells simultaneously stained with Si NPs and DRAQ5
One research field in particular is about the development of novel bio-functionalized nanomaterials and nanocarriers for cell imaging and drug delivery. For this purpose, Zeolite-L crystals have been using. Zeolite-L are synthetic, porous, crystalline aluminosilicate with cylindrical shape and hexagonal symmetry with channels running along the structure, which can be used to develop multifunctional nanomaterials, exploiting both internal channel filling and surface modification.
Peptide nucleic acids (PNAs), which are very efficient oligonucleotide mimics for the recognition of DNA or RNA, arise as very interesting probes since they show a very high affinity towards DNA and, overall, a high stability to chemical or enzymatic degradation.
Peptide nucleic acids can be used to develop novel PNA-modified zeolites to create hybrid multifunctional nanomaterials combining the host properties of the material with the relevant biological and chemical features of PNA strands. Targeting specific molecules into the cells, like miRNA sequences involved in cancer proliferation, will constitute one of the main goals using such a hybrid system.
At the same time, properly modified Zeolite-L can also bind to DNA strands, so that novel nanocarriers with unique properties at the interface between inorganic material and biomolecules could be developed. DNA-modified-zeolite-L nanocrystals can also host different kinds of molecules in the pore system, revealing to be excellent carriers to deliver into living cells both a huge amount of stranger DNA and what is initially caged inside the channels. The multifunctionality of these systems could have a great impact in the field of DNA transfection, combined with the possibility of a drug delivery at the same time.