The world’s first in vivo nano-coding control system was developed. This precise system will allow the development of novel implant materials.

▲(From left) Min Sun-hong (first author, integrated Master/Ph.D course), Dr. Jeon Yoo-sang (first author), Professor Kim Young-keun (corresponding author), and Professor Kang Hee-min (corresponding author)

Professor Kang Hee-min and Professor Kim Young-keun’s team of the Department of Materials Science and Engineering, Korea University, has developed the world’s first in vivo nano-coding control system that can control the adhesion and differentiation of stem cells on the surface of implanted materials. The results obtained by the team were published in the internationally renowned journal ‘Advanced Materials (Impact Factor: 27.398)’ on August 21.

  * Title of article: Independent Tuning of Nano-Ligand Frequency and Sequences Regulates the Adhesion and Differentiation of Stem Cells
  * Authors: Min Sun-hong (first author, integrated Master/Ph.D course, Korea University), Dr. Jeon Yoo-sang (first author, Korea University), Professor Kim Young-keun (corresponding author, Department of Materials Science and Engineering, Korea University), and Professor Kang Hee-min (corresponding author, Department of Materials Science and Engineering, Korea University)

Stem cells can sense the surrounding environment and accordingly differentiate into tissue cells corresponding to the environment. Because of this unique feature, stem cells have drawn much attention in the field of regenerative medicine and engineering, as they may be induced to differentiate into the tissue cells of various organs, including bones, adipose tissue, muscles, myocardia, vessels and cartilage. However, controlling the in vivo adhesion and differentiation of stem cells remains a challenge.
 
The joint research team of the Department of Materials Science and Engineering employed an iron-gold multilayer nanowire (nano-barcode) prepared using a nano-template and pulse electroplating. They thereby developed the world’s first system that can control the adhesion and differentiation of stem cells through a nano-coding that enables one to precisely control the frequency and sequence of ligands on the surface of an implanted material.

▲Schematic diagram of the in vivo nano-coding control system.

The nano-barcode was varied by the frequency and sequence of its segments. It was found that as the frequency of the segments decreased and the sequence was placed nearer one end of the segment, the adhesion rate of stem cells and their rate of differentiation into osteocytes were successfully enhanced.

Professor Kim Young-keun and Professor Kang Hee-min of the Department of Materials Science and Engineering, who are the corresponding authors of the article, explained the significance of the study, saying “We have developed a precise coding control system to control ligand frequency and sequence using nano-barcodes. This allows us to verify the possibility of the in vivo control of stem cells on implant materials. This technology is expected to be applied to customized regenerative therapy and immunotherapy.”

The research was supported by the Ministry of Science and ICT and the National Research Foundation of Korea (NRF) through the Basic Science Research Program (under Young Researcher Program and Mid-Career Researcher Program).

▲Schematic diagram of the stem cell control system based on nano-coding of the frequency and sequence.

※ Terms
  * Stem cells: Stem cells, less differentiated cells than the other cells constituting tissues, are capable of differentiating into specific cells depending on the surrounding environment. Therefore, stem cells have drawn much attention for customized treatments, including bioregeneration, artificial organ formation and cytotherapy.

 * Nano-barcode: Nano-barcode refers to a nano-structure constructed using multi-layer nanowires to form bamboo-like segments of alternately arranged heterogeneous metals, such as iron and gold, wherein the frequency and sequence of the individual segments may be changed to vary the properties of the nano-barcode.

 * Pulse electroplating: A method of synthesizing nano-materials by applying different magnitudes of current or voltage to an electroplating solution according to the reduction potential of individual metal ions in order to induce the reduction of one specific metal ion.

 * RGD ligand: RGD ligand refers to the amino acid sequence of fibronectin, which is one of the proteins of the extracellular matrix that mediates cell adhesion. Integrin, a receptor in the cell membrane, recognizes RGD ligands and causes them to adhere to a cell.