Is nanoparticle functionalization a versatile approach to meet challenges of drug and gene delivery?

In the last decade the development of polymeric nanoparticles (NPs) as tools for controlled drug or gene delivery has been attracting a lot of interest, thanks to their ability to localize and sustain the release of active molecules in situ. Polymeric NPs are commonly defined as colloidal particles in the range of 1 to 100 nm that are able to encapsulate or adsorb drugs and active compounds within their structure. High surface area to volume ratio, biocompatibility and biodegradability represent polymeric NPs main peculiarities and together with versatility in terms of size, potential surface and hydrophilic or lipophilic characteristics it has made them suitable as drug- or gene -delivery systems. The greatest opportunity offered by polymeric NPs is the possibility to tune their structure both through functionalized polymers during nanoparticle synthesis and with surface functionalization over final NPs. These features are able to increase the selectivity of the device and improve its ability as a targeted drugdelivery system to control the release over time. Many strategies of surface coating and functionalization are reported to improve the delivery ability of NPs.