Controlled Manufacturing of Multimetallic Building Blocks for Hybrid Nanomaterials – EEJournal

The new method can be used to construct copolymers comprising different metal species, which have potential uses in catalysis and drug discovery

Polymers with different metal complexes in their side chains are considered promising high performance materials with a wide variety of applications. However, conventional manufacturing methods are not suitable for constructing such polymers because controlling their resulting metallic composition is complicated. Recently, Japanese scientists have developed a method to overcome this limitation and successfully produce multimetallic copolymers, which can be used as building blocks to create future hybrid materials.

From plastics to clothing to DNA, polymers are everywhere. Polymers are very versatile materials made up of long chains of repeating units called monomers. Polymers containing metal complexes on their side chains have enormous potential as hybrid materials in a variety of fields. This potential only increases with the inclusion of more metal species in polymers. But conventional methods of making polymers with metal complexes are not suitable for building multimetallic polymers, because controlling the composition of metal species in the resulting polymer is complex.

Recently, a research team, led by Assistant Professor Shigehito Osawa and Professor Hidenori Otsuka from Tokyo University of Science, proposed a new polymerization method that can overcome this limitation. Dr. Osawa explains: “The usual method of preparing such complexes is to engineer a polymer with ligands (molecular ‘backbones’ that connect other chemical species) then add the metal species to form complexes on it. But each metal has a different binding affinity for the ligand, making it difficult to control the resulting structure. By considering polymerizable monomers with complexes of different metal species, we can effectively control the composition of the resulting copolymer.The study was posted online on April 1, 2022 and published in Volume 58, Issue 34 of Chemical communications April 30, 2022.

When the monomers that make up a polymer are themselves polymers, the polymer is called a copolymer. For their study, the scientists designed a dipicolylamine acrylate (DPAac) monomer. DPA was chosen because it is an excellent metal ligand and has been used in various biochemical applications. They then polymerized DPAAc with zinc (Zn) and platinum (Pt) to form two polymer chains with metal complexes – DPAZn(II)Ac and DPAPt(II)Ac. They then copolymerized the two monomers. They found that not only could they successfully create a copolymer, but they could also control its metal composition by varying the feed composition of the monomers.

Next, they applied this copolymer as a building block to make nanoparticles using plasmid deoxyribonucleic acid (DNA) as a template. Plasmid DNA was chosen as the template because the two constituent monomers are known to bind to it. The formation of the resulting nanoparticle polymer complexes with DNA (polyplexes) was confirmed using high-resolution scanning electron microscopy and energy dispersive X-ray spectroscopy.

This technique, now patent pending, can be extended to a new method of manufacturing intermetallic nanomaterials. “Intermetallic catalytic nanomaterials are known to have significant advantages over nanomaterials containing only a single metal species, says Dr. Osawa.

The polyplexes formed in the study are DNA-binding molecules, indicating that they could be used to develop cancer drugs and gene carriers. The proposed manufacturing method will also lead to advances in catalysis that move away from precious metals like platinum. “These multimetallic copolymers can serve as building blocks for future macromolecular metal complexes of many varieties.concludes Dr. Osawa.

The results of this study will certainly have considerable consequences in the field of polymer chemistry.

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Reference

Title of the original article: Controlled polymerization of metal complex monomers – fabrication of random copolymers comprising different metal species and nano-colloids

Log: Chemical communications

About Tokyo University of Science

Tokyo University of Science (TUS) is a well-known and respected university, and the largest private research university specializing in science in Japan, with four campuses in central Tokyo and its suburbs and in Hokkaido. Founded in 1881, the university has continuously contributed to the scientific development of Japan by instilling a love of science in researchers, technicians and educators.

With a mission to “create science and technology for the harmonious development of nature, human beings and society”, TUS has undertaken a wide range of research from basic to applied science. TUS has taken a multidisciplinary approach to research and undertaken intensive studies in some of today’s most vital areas. TUS is a meritocracy where the best in science is recognized and nurtured. It is the only private university in Japan that has produced a Nobel laureate and the only private university in Asia to produce Nobel laureates in the field of natural sciences.

About the Assistant Professor Shigehito Osawa from Tokyo University of Science

Shigehito Osawa received a PhD in Materials Engineering from the University of Tokyo, Japan in 2016. He worked as a research scientist at the Kawasaki Industrial Promotion Institute from 2016 to 2018. He then joined the University of Tokyo Science, where he is now Assistant Professor in the Department of Applied Chemistry. His research interests are in the areas of polymer materials and polymer chemistry. He has published 24 peer-reviewed papers and his patent-pending technology is currently under review. He is currently a member of the Water Frontiers Research Center (WaTUS).