Research group "Hybrid Materials"

Group leader:


Martin Humenik, PhD. 0921-55 7347
  martin.humenik(.at.)bm.uni-bayreuth.de
   

Research overview:

Proteins, which we are focusing on, self-assemble into cross-beta nanofibrils, supramolecular structures of densely packed beta sheets. Such fibrils, typically 2-5 nm in diameter and several hundred nm long, possess high aspect ratio, high environmental and chemical stability and their mechanical rigidity can reach the best natural materials such as spider silk or bones. Such systems are attractive for creation of ordered nanomaterials especially in combination with metallic nanoparticles, enzymes and dyes for novel electronic, optic and catalytic properties. Nucleic acids could self-assemble into many different nano-structures with precision and predictability which is unrivaled among the natural and synthetic materials. One of the best example for such high fidelity is programming and folding of DNA origami. To take advantage of both, protein and DNA materials, we combine structural proteins such as spider silk and nucleic acids in hybrid chemical entities. The DNA-spider silk conjugates represent promising building blocks for the development of new nanostructured self-assembling materials possessing the chemical and mechanical robustness of cross-beta nano-fibrils along with the programmability of DNA. We investigate fundamental properties of DNA-protein hybrid systems to realize its utilization in materials research. We are studding new chemical modifications and conjugations of the building blocks, arrangements and assembly of protein moieties upon hybridizations of DNA, morphology and structure of conjugate fibrils as well as their self-organization into hierarchical nanostructures upon DNA interactions. Profound understanding of the system will allow us to create ordered and programmable proteinaceous structures via DNA sequence design.

 

Hybrid materials in bottom-up manner: Hybrids made by chemical conjugation of DNA and protein; protein moieties arranged upon designed DNA hybridization, fibrils of the hybrids associated into nano-ribbons and micro-rafts due to complementary interactions of DNA.
 

Self-assembly is based on autonomous mechanism of non-covalent interactions between distinct building blocks. Related processes do not require external energy source and have no limitation in dimensional scaling. Such “bottom up” building results in nature into formation of nanostructured materials organized at different hierarchical levels, as represented by highly stable bones, shells or spider silks. These attributes of self-assembly make it highly attractive for materials science where development of new materials will rely on controlled nano-structuring and ordering in future.

Selected publications:

• Hybrid materials:

Humenik, M.* & Scheibel, T. (2014). Self-assembly of nucleic acids, silk and hybrid materials thereof. Journal of Physics: Condensed Matter 26, 503102.

Humenik, M.*, Drechsler, M. & Scheibel, T. (2014). Controlled Hierarchical Assembly of Spider Silk-DNA Chimeras into Ribbons and Raft-Like Morphologies. Nano Letters 14, 3999-4004.

Humenik, M.* & Scheibel, T. (2014). Nanomaterial Building Blocks Based on Spider Silk–Oligonucleotide Conjugates. ACS Nano 8, 1342-1349

• Protein self-assembly:

Humenik, M., Smith, A. M., Arndt, S. & Scheibel, T. (2015). Ion and seed dependent fibril assembly of a spidroin core domain. Journal of Structural Biology 191, 130-138.

Humenik, M., Magdeburg, M. & Scheibel, T. (2014). Influence of repeat numbers on self-assembly rates of repetitive recombinant spider silk proteins. Journal of Structural Biology 186, 431-437.

Humenik, M., Scheibel, T. & Smith, A. (2011). Spider Silk: Understanding the Structure–Function Relationship of a Natural Fiber. In Progress in Molecular Biology and Translational Science (Howorka, S., ed.), Vol. 103, pp. 131-185. Academic Press.

Humenik, M., Smith, A. M. & Scheibel, T. (2011). Recombinant Spider Silks—Biopolymers with Potential for Future Applications. Polymers 3, 640-661.

• DNA-Protein conjugates:

Humenik, M., Poehlmann, C., Wang, Y. & Sprinzl, M. (2008). Enhancement of Electrochemical Signal on Gold Electrodes by Polyvalent Esterase-Dendrimer Clusters. Bioconjugate Chemistry 19, 2456-2461.

Humenik, M., Huang, Y., Wang, Y. & Sprinzl, M. (2007). C-terminal incorporation of bio-orthogonal azide groups into a protein and preparation of protein-oligodeoxynucleotide conjugates by Cu(I)-catalyzed cycloaddition. ChemBioChem 8, 1103-1106.

Wang, Y., Stanzel, M., Gumbrecht, W., Humenik, M. & Sprinzl, M. (2007). Esterase 2-oligodeoxynucleotide conjugates as sensitive reporter for electrochemical detection of nucleic acid hybridization. Biosensors & Bioelectronics 22, 1798-1806.