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A novel cell-printing method and its application to hepatogenic differentiation of human adipose stem cell-embedded mesh structures.

Ahn SH, Lee HJ, Lee JS, Yoon H, Chun W, Kim GH - Sci Rep (2015)

Bottom Line: In the shell of the nozzle, a cross-linking agent flowed continuously onto the surface of the dispensed bioink in the core nozzle, so that the bioink struts were rapidly gelled, and any remnant cross-linking solution during the process was rapidly absorbed into the working stage, resulting in high cell-viability in the bioink strut and stable formation of a three-dimensional mesh structure.To demonstrate the applicability of the technique, preosteoblasts and human adipose stem cells (hASCs) were used to obtain cell-laden structures with multi-layer porous mesh structures.The fabricated cell-laden mesh structures exhibited reasonable initial cell viabilities for preosteoblasts (93%) and hASCs (92%), and hepatogenic differentiation of hASC was successfully achieved.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomechatronic Engineering, College of Biotechnology and Bioengineering, Sungkyunkwan University (SKKU), Suwon, South Korea.

ABSTRACT
We report a cell-dispensing technique, using a core-shell nozzle and an absorbent dispensing stage to form cell-embedded struts. In the shell of the nozzle, a cross-linking agent flowed continuously onto the surface of the dispensed bioink in the core nozzle, so that the bioink struts were rapidly gelled, and any remnant cross-linking solution during the process was rapidly absorbed into the working stage, resulting in high cell-viability in the bioink strut and stable formation of a three-dimensional mesh structure. The cell-printing conditions were optimized by manipulating the process conditions to obtain high mechanical stability and high cell viability. The cell density was 1 × 10(7) mL(-1), which was achieved using a 3-wt% solution of alginate in phosphate-buffered saline, a mass fraction of 1.2 wt% of CaCl2 flowing in the shell nozzle with a fixed flow rate of 0.08 mL min(-1), and a translation velocity of the printing nozzle of 10 mm s(-1). To demonstrate the applicability of the technique, preosteoblasts and human adipose stem cells (hASCs) were used to obtain cell-laden structures with multi-layer porous mesh structures. The fabricated cell-laden mesh structures exhibited reasonable initial cell viabilities for preosteoblasts (93%) and hASCs (92%), and hepatogenic differentiation of hASC was successfully achieved.

No MeSH data available.


Unstable cell-laden structure and rheological properties.(a) Cell-laden mesh structure fabricated using the CD-CS process with a glass dispensing stage. (b) The storage modulus G′ and the complex viscosity n* of cell-laden alginate cross-linked on a glass dispensing stage with two different cross-linking times. (c) A comparison of the storage moduli at 0.1 Hz.
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f2: Unstable cell-laden structure and rheological properties.(a) Cell-laden mesh structure fabricated using the CD-CS process with a glass dispensing stage. (b) The storage modulus G′ and the complex viscosity n* of cell-laden alginate cross-linked on a glass dispensing stage with two different cross-linking times. (c) A comparison of the storage moduli at 0.1 Hz.

Mentions: Because of the ability to fabricate cylindrical struts using the CD-CS process, we attempted to form cell-laden mesh structures. Biomedical scaffolds for tissue regeneration should be mechanically stable and exhibit highly porous 3D structures to enable cell-to-cell and cell-to-matrix interactions, encourage the formation of blood vessels, and to convey nutrients and remove metabolic waste19. Figure 2(a) shows the CD-CS cell-dispensing process using a glass dispensing stage. The optical images show the fabricated cell-laden mesh structure, which had dimensions of 20 × 20 × 2 mm3. This structure appeared to be a stable mesh structure; however, as shown in the magnified image, the cell-laden micro-struts were detached from each other, which may lead to an unstable porous mesh structure. Such instability of the micron-scale struts in the mesh structure was attributed to some cross-linking agent (i.e., CaCl2 solution) remaining in the dispensing stage during the fabrication process, which inhibits the formation of dispensed cylindrical cell-laden struts, as the inter-strut adhesive forces are weak. We observed the time-dependent modulus of the dispensed struts with the cross-linking agent using a glass dispensing stage to test the rheological properties. Figure 2(b) shows the complex viscosity n* and storage modulus G′ of the 3- and 5-wt% cell-laden alginates with two cross-linking times, i.e., 1 min and 5 min, and with a CaCl2 solution concentration of 1.2 wt%. The storage modulus was significantly larger with the longer cross-linking time, as shown in Fig. 2(c). These rheological results show that the cell-laden struts became harder as the processing time increased, reducing the inter-strut adhesion, and possibly leading to a decrease in the activities of the embedded cells.


A novel cell-printing method and its application to hepatogenic differentiation of human adipose stem cell-embedded mesh structures.

Ahn SH, Lee HJ, Lee JS, Yoon H, Chun W, Kim GH - Sci Rep (2015)

Unstable cell-laden structure and rheological properties.(a) Cell-laden mesh structure fabricated using the CD-CS process with a glass dispensing stage. (b) The storage modulus G′ and the complex viscosity n* of cell-laden alginate cross-linked on a glass dispensing stage with two different cross-linking times. (c) A comparison of the storage moduli at 0.1 Hz.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4544022&req=5

f2: Unstable cell-laden structure and rheological properties.(a) Cell-laden mesh structure fabricated using the CD-CS process with a glass dispensing stage. (b) The storage modulus G′ and the complex viscosity n* of cell-laden alginate cross-linked on a glass dispensing stage with two different cross-linking times. (c) A comparison of the storage moduli at 0.1 Hz.
Mentions: Because of the ability to fabricate cylindrical struts using the CD-CS process, we attempted to form cell-laden mesh structures. Biomedical scaffolds for tissue regeneration should be mechanically stable and exhibit highly porous 3D structures to enable cell-to-cell and cell-to-matrix interactions, encourage the formation of blood vessels, and to convey nutrients and remove metabolic waste19. Figure 2(a) shows the CD-CS cell-dispensing process using a glass dispensing stage. The optical images show the fabricated cell-laden mesh structure, which had dimensions of 20 × 20 × 2 mm3. This structure appeared to be a stable mesh structure; however, as shown in the magnified image, the cell-laden micro-struts were detached from each other, which may lead to an unstable porous mesh structure. Such instability of the micron-scale struts in the mesh structure was attributed to some cross-linking agent (i.e., CaCl2 solution) remaining in the dispensing stage during the fabrication process, which inhibits the formation of dispensed cylindrical cell-laden struts, as the inter-strut adhesive forces are weak. We observed the time-dependent modulus of the dispensed struts with the cross-linking agent using a glass dispensing stage to test the rheological properties. Figure 2(b) shows the complex viscosity n* and storage modulus G′ of the 3- and 5-wt% cell-laden alginates with two cross-linking times, i.e., 1 min and 5 min, and with a CaCl2 solution concentration of 1.2 wt%. The storage modulus was significantly larger with the longer cross-linking time, as shown in Fig. 2(c). These rheological results show that the cell-laden struts became harder as the processing time increased, reducing the inter-strut adhesion, and possibly leading to a decrease in the activities of the embedded cells.

Bottom Line: In the shell of the nozzle, a cross-linking agent flowed continuously onto the surface of the dispensed bioink in the core nozzle, so that the bioink struts were rapidly gelled, and any remnant cross-linking solution during the process was rapidly absorbed into the working stage, resulting in high cell-viability in the bioink strut and stable formation of a three-dimensional mesh structure.To demonstrate the applicability of the technique, preosteoblasts and human adipose stem cells (hASCs) were used to obtain cell-laden structures with multi-layer porous mesh structures.The fabricated cell-laden mesh structures exhibited reasonable initial cell viabilities for preosteoblasts (93%) and hASCs (92%), and hepatogenic differentiation of hASC was successfully achieved.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomechatronic Engineering, College of Biotechnology and Bioengineering, Sungkyunkwan University (SKKU), Suwon, South Korea.

ABSTRACT
We report a cell-dispensing technique, using a core-shell nozzle and an absorbent dispensing stage to form cell-embedded struts. In the shell of the nozzle, a cross-linking agent flowed continuously onto the surface of the dispensed bioink in the core nozzle, so that the bioink struts were rapidly gelled, and any remnant cross-linking solution during the process was rapidly absorbed into the working stage, resulting in high cell-viability in the bioink strut and stable formation of a three-dimensional mesh structure. The cell-printing conditions were optimized by manipulating the process conditions to obtain high mechanical stability and high cell viability. The cell density was 1 × 10(7) mL(-1), which was achieved using a 3-wt% solution of alginate in phosphate-buffered saline, a mass fraction of 1.2 wt% of CaCl2 flowing in the shell nozzle with a fixed flow rate of 0.08 mL min(-1), and a translation velocity of the printing nozzle of 10 mm s(-1). To demonstrate the applicability of the technique, preosteoblasts and human adipose stem cells (hASCs) were used to obtain cell-laden structures with multi-layer porous mesh structures. The fabricated cell-laden mesh structures exhibited reasonable initial cell viabilities for preosteoblasts (93%) and hASCs (92%), and hepatogenic differentiation of hASC was successfully achieved.

No MeSH data available.