Synthesis and bioactivity of copolymers with fragments of heparin

Nanomedicine: perspective and promises with ligand-directed molecular imaging

Molecular imaging and targeted drug delivery play an important role toward personalized medicine, which is the future of patient management. Of late, nanoparticle-based molecular imaging has emerged as an interdisciplinary area, which shows promises to understand the components, processes, dynamics and therapies of a disease at a molecular level. The unprecedented potential of nanoplatforms for early detection, diagnosis and personalized treatment of diseases, have found application in every biomedical imaging modality. Biological and biophysical barriers are overcome by the integration of targeting ligands, imaging agents and therapeutics into the nanoplatform which allow for theranostic applications. In this article, we have discussed the opportunities and potential of targeted molecular imaging with various modalities putting a particular emphasis on perfluorocarbon nanoemulsion-based platform technology.

Single-step process to produce surface-functionalized polymeric nanoparticles

Nanoparticles (NPs) are a versatile medium for the localization of therapeutics to tumors and for cellular and tissue imaging. The ability to impart targeting capability or enhance cellular uptake is dependent in part on the presentation of relevant surface functionality, among other design parameters. Currently, the production of functionalized polymeric NPs requires the a priori synthesis of polymers bearing such functionality. Here we describe a process to produce functionalized polymeric NPs derived from nonfunctional polymers in a single step. This was achieved by tailoring the solvation of the polymer using a binary solvent system such that the addition of an aqueous phase rich in water-soluble polymer or polyelectrolytes results in the formation of NPs with the concomitant functionalization of NP surfaces with the polymeric moieties introduced into the aqueous phase. This strategy also allows for easy control over NP size independent of surface functionality. We have demonstrated that poly(lactic-co-glycolic acid) (PLGA) NPs bearing surface functionality as diverse as biological polysaccharides such as heparin, water-soluble ionic polymers, and poly(ethylene glycol) can be prepared under identical conditions in a single step, with surface coverage (mass %) ranging from 3 to >70%. We expect this novel process to enable complex surface engineering of NP chemistry that hitherto was impossible using existing approaches.

Synthesis, characterization, and blood compatibility of polyamidoamines copolymers

This work reports the development of new non-thrombogenic polymers based on the linear polymers of polyamidoamines (PAAs), having heparin binding ability, obtained by polyaddition of secondary amines to N,N'-methylene bis-acrylamide. PAAs could not be used directly in the making of blood-contacting materials due to their poor mechanical strength. In order to overcome this lacuna, copolymers of amidoamine with methylmethacrylate (MMA) were prepared. Characterization studies indicated that the PAAs have been suitably incorporated into the MMA matrix. The relative hydrophilic nature of the synthesized copolymers was established from the measurement of water contact angle. The heparinized copolymers showed significant improvement in non-thrombogenic characteristics.