Magnetically Controlled Growth‐Factor‐Immobilized Multilayer Cell Sheets for Complex Tissue Regeneration

Abstract

The scaffold-free cell-sheet technique plays a significant role in stem-cell-based regeneration. Furthermore, growth factors are known to direct stem cell differentiation and enhance tissue regeneration. However, the absence of an effective means to incorporate growth factors into the cell sheets hinders further optimization of the regeneration efficiency. Here, a novel design of magnetically controlled "growth-factor-immobilized cell sheets" is reported. A new Fe O magnetic nanoparticle (MNP) coated with nanoscale graphene oxide (nGO@Fe O ) is developed to label stem cells and deliver growth factors. First, the nGO@Fe O MNPs can be easily swallowed by dental-pulp stem cells (DPSCs) and have no influence on cell viability. Thus, the MNP-labeled cells can be organized via magnetic force to form multilayered cell sheets in different patterns. Second, compared to traditional Fe O nanoparticles, the graphene oxide coating provides plenty of carboxyl groups to bind and deliver growth factors. Therefore, with these nGO@Fe O MNPs, bone-morphogenetic-protein-2 (BMP2) is successfully incorporated into the DPSCs sheets to induce more bone formation. Furthermore, an integrated osteochondral complex is also constructed using a combination of DPSCs/TGFβ3 and DPSCs/BMP2. All these results demonstrate that the new cell-sheet tissue-engineering approach exhibits promising potential for future use in regenerative medicine.

An in vivo comparative study of the gelatin microtissue‐based bottom‐up strategy and top‐down strategy in bone tissue engineering application

“…These modular tissues can be established using various methods including self‐assembled aggregation, microfabrication of cell‐laden hydrogels, the creation of cell sheets, or direct printing of tissues . Once fabricated, these modular tissues can be assembled into macroscopic tissue constructs through many approaches such as random packing in a mold, directed assembly using microfluidics, magnetic assembly, and acoustics assembly . Compared to the traditional TD fabrication methods, BU strategies have the following advantages: Many natural tissues are organized into repeating functional units similar to the osteon in the bone, the nephron in the kidney, and the lobules in the liver.…”

Advanced Functional Biomaterials for Stem Cell Delivery in Regenerative Engineering and Medicine

“…After the cells got confluent, decreasing the temperature leads to rapid hydration and swell of the PNIPAAm layer which promotes the complete detachment of a cell sheet . Magnetic force can also be used to fabricate cell sheets in different patterns via cells labeled with magnetic particles . The majority of current researches using implantable delivery systems were performed in vitro but not transplanted in vivo, except in bone regeneration.…”

Structurally Tunable Reduced Graphene Oxide Substrate Maintains Mouse Embryonic Stem Cell Pluripotency

“…[23] Water and DKK1 (10 µg mL −1 ), diluted with water, were separately added to the RGO-30 substrates and then the substrates were cooled at 4 °C for 2 h. The water-modified RGO substrate was used as a control, and the modification was detected by western blotting. The method of modifying graphene oxide with protein was based on previously published research.…”

“…They have been widely used in the research of stem cells. [23] However, studies on whether graphene and its derivatives can maintain the pluripotency of ESCs in the absence of a feeder in vitro have not been widely reported. [22] The nGO@Fe 3 O 4 magnetic particles possessing numerous bindable carboxyl groups could carry bone morphogenetic protein 2 (BMP 2) and transforming growth factor β 3 (TGFβ 3) after being modified by graphene and related derivatives; therefore, the composite particles could regulate the differentiation of stem cells after being transported into cells.…”