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About us Faculty of Science and Engineering PhD ceremonies

Surface supported dynamic combinatorial chemistry for biomacromolecule recognition

PhD ceremony:Mr X. (Xiaoming) Miao
When:November 01, 2019
Supervisors:prof. dr. S. (Sijbren) Otto, prof. dr. R.C. (Ryan) Chiechi
Where:Academy building RUG
Faculty:Science and Engineering

In this thesis, DCC based selective chemical functionalization of nanomaterials is investigated. The thesis is divided into three main chapters dealing with the preparation of water-dispersed nanoparticles (chapter 2), dynamic hydrazone exchange on the surface of dendrimers (chapter 3) and specific functionalization of dendrimers by dynamic imine chemistry (chapter 4).

In chapter 2, SPIONs coated with zwitterionic ligands have been synthesized, which remained stable in aqueous solution over a long time span (> 60 days). Specifically, a choline phosphate based zwitterionic ligand carrying an aldehyde group enabled the surface functionalization by hydrazone chemistry, which demonstrates the potential of SPIONs as a new platform for surface supported DCC.

In chapter 3 we could demonstrate reversible hydrazone chemistry on zwitterionic dendrimers (PAMAM). The exchange behavior and thermodynamic equilibrium were first verified by NMR and UPLC, while after the addition of three DNA oligonucleotides templates, the amplification of the library members with higher affinities towards these DNA templates was observed. A positively charged hydrazone on the surface of PAMAM showed specifically strong amplification presumably due to its ability to bind to the negatively charged DNA.

In chapter 4, we have shown dynamic imine chemistry on the surface of zwitterionic dendrimers. This illustrates that DCC provides a facile and efficient method to generate specific receptors to bind DNA, in one case even sequence-selectively.