Modern medicine increasingly relies on advanced technologies including nanotechnology. Particularly promising are nanomaterials capable of performing several simultaneous functions, such as imaging, controlled drug delivery, therapy activated by light or other physical factors. Upconverting nanoparticles based on lanthanide fluorides are now being extensively studied for the use in theranostics. However, their surface functionalization necessary to obtain the required biocompatibility is a difficult and critical task. Most of the known methods for the synthesis of nanoluminophores based on lanthanide fluorides results in nanocrystallites coated with hydrophobic or highly toxic molecules, which precludes their use in an aqueous environment and at physiological conditions. Most of the known protocols relies on the adsorption of the polymer / surfactants or other molecules on the nanoparticle surface, where ligands are weakly bound to the carrier surface. This results in poor stability of the obtained nanoluminophores, a tendency for aggregation and precipitation from the solution. So far, there are no market suppliers offering the NaYF4 type nanoluminophores that would be well and stably dispersible in aqueous solutions, furnished with functionalities enabling further functionalization with biomolecules.
The offered technology for the surface modification of upconverting nanoparticles allows to prepare nanoparticles featuring a excellent dispersibility in aqueous solutions and good stability. The modification is based on a functional polymer, which is crosslinked during the process on the surface of nanocrystallite forming a stable hydrophilic coat. The polymer contains functional groups that enables covalent attachment of various biomolecules, for example, antibodies. The technology is simple to perform and is highly efficient, in terms of the product yield. The quality and reproducibility of the process allows for the implementation for the preparation of commercial products.
The main advantage of the technology is the formation of a crosslinked and thus stable coating on the surface of a nanocrystallite. This ensures coating stability under different environmental conditions. The process of functionalization is characterized by high yield -in contrast to current methods – and highly reproducible, the resulting functional nanoparticles shows high stability in aqueous solutions even in the long time period. Stability depends also on the type of particles used for bio-functionalization, when modified with proteins only insignificant precipitation of the nanoluminophore during long-term storage can be observed. Another important advantage of the proposed technology is that modifications are performed in the aqueous medium without the use of toxic solvents. In addition, the technology enables the immobilization of a wide range of biological macromolecules (eg. proteins, peptides, aptamers, polysaccharides, oligosaccharides, small molecule haptens).
- Structures /antigens marking in tissues and living organisms
- Diagnostic tests
- Nanosensors and phototherapeutics
Posted by Wrocławskie Centrum Badań EIT+, Posted on 24.05.2016