Applications of Functionalized PMMA Derivatives in Nanobiomedicine and Nanotechnology

PMMA is a non water soluble polymer that can be synthesized in a very controllable way by different polymerization techniques, with a narrow molecular distribution and it is easily functionalizable. Among these advantages, this polymer is very stable and easy to handle.

CIDETEC (Centre for Electrochemical Technologies) was created in 1997 as a non-profit Foundation whose mission is to serve both the industrial sectors related to electrochemistry and the Administration and society in general, its core activity being the field of applied research.

The New Materials Department it has been made an effort in the design and synthesis of PMMA derivatives with application in nanobiomedicine and nanotechnology.

In a recent collaboration with the Higher Centre for Scientific Research (CSIC) and the University of Berkeley (U.S.), CIDETEC has designed some PMMA derivatives that have been applied in the functionalization of carbon nanotubes, for the development of a highly sensitive electrochemical sensor that can detect possible mutations in DNA. The sensor consisted in a single nanotube transistor.

As a proof of concept, DNA probes were anchored to the surface of the nanotubes. The PMMA derivative was employed to link the DNA probes in a simply way on the surface of the carbon nanotube.

The polymer coating was efficiently adsorbed on the surface of the nanotube due to interactions with the hydrophobic polymer backbone. It provided stable binding for DNA probes through robust amide linkages. It was synthesized with certain amount of PEG chains to avoid non specific interactions.

Finally, the heteroatoms present in the polymer chain provide charge transfer that improved transistor characteristics. All these synergic effects allowed detecting DNA interactions on the surface of a single carbon nanotube without need to modify them.

In forthcoming years, nanobiosensors will be able to detect other types of molecules and we will be able to use them to study genetic illnesses.

In a different application, CIDETEC has also designed some PMMA derivatives for the synthesis of single-molecule polymeric nanoparticles.

In the work published in Macromolecular Rapid communications, random PMMA terpolymers were synthesized and designed to form very small (<10 nm) functionalizable nanoparticles. The terpolymer consisted in a PMMA backbone functionalized with small amounts azide and alquine containing monomers.

AFM image of polymeric nanoparticles.

These two functional groups react together in presence of copper to form rings through a very efficient chemical reaction described by Sharpless. This kind of reaction is an example of those known as click reactions.

Adequate reaction conditions, forced the intramolecular click-reaction between those functional groups in the same polymeric chain. This method leads to covalently stabilized single-molecule nanoparticles.

The method was employed to decorate the nanoparticles in a second click reaction with an aminoacid layer.

The versatility of the method makes these nanoparticles good candidates to be designed as carriers in drug delivery or to be applied as imaging agents.

Progress in this area will lead to new developments in nanomedicine that will provide safer medicines and more precise diagnostic methods.