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Controlled Delivery of Human Cells by Temperature Responsive Microcapsules.

Mak WC, Olesen K, Sivlér P, Lee CJ, Moreno-Jimenez I, Edin J, Courtman D, Skog M, Griffith M - J Funct Biomater (2015)

Bottom Line: However, its full potential is limited by the rapid loss of introduced therapeutic cells before their full effects can be exploited, due in part to anoikis, and in part to the adverse environments often found within the pathologic tissues that the cells have been grafted into.Cell encapsulation and controlled release was demonstrated using human fibroblasts as model cells, as well as a therapeutically relevant cell line-human umbilical vein endothelial cells (HUVECs).While such temperature responsive cell microcapsules promise effective, controlled release of potential therapeutic cells at physiological temperatures, further work will be needed to augment the composition of the microcapsules and optimize the numbers of cells per capsule prior to clinical evaluation.

View Article: PubMed Central - PubMed

Affiliation: Integrative Regenerative Medicine Centre, Department of Clinical and Experimental Medicine, Linköping University, SE58185, Linköping, Sweden. mamak@ifm.liu.se.

ABSTRACT
Cell therapy is one of the most promising areas within regenerative medicine. However, its full potential is limited by the rapid loss of introduced therapeutic cells before their full effects can be exploited, due in part to anoikis, and in part to the adverse environments often found within the pathologic tissues that the cells have been grafted into. Encapsulation of individual cells has been proposed as a means of increasing cell viability. In this study, we developed a facile, high throughput method for creating temperature responsive microcapsules comprising agarose, gelatin and fibrinogen for delivery and subsequent controlled release of cells. We verified the hypothesis that composite capsules combining agarose and gelatin, which possess different phase transition temperatures from solid to liquid, facilitated the destabilization of the capsules for cell release. Cell encapsulation and controlled release was demonstrated using human fibroblasts as model cells, as well as a therapeutically relevant cell line-human umbilical vein endothelial cells (HUVECs). While such temperature responsive cell microcapsules promise effective, controlled release of potential therapeutic cells at physiological temperatures, further work will be needed to augment the composition of the microcapsules and optimize the numbers of cells per capsule prior to clinical evaluation.

No MeSH data available.


Related in: MedlinePlus

Light micrographs showing cell capsules prepared with various initial cell concentrations (A) 2,000,000, (B) 4,000,000 and (C) 8,000,000 cells·mL−1, respectively. (D) Size distribution of capsules prepared with various hydrogel formulation. (E) Cell number(s) per single capsule (as a function of various initial cell concentrations).
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jfb-06-00439-f002: Light micrographs showing cell capsules prepared with various initial cell concentrations (A) 2,000,000, (B) 4,000,000 and (C) 8,000,000 cells·mL−1, respectively. (D) Size distribution of capsules prepared with various hydrogel formulation. (E) Cell number(s) per single capsule (as a function of various initial cell concentrations).

Mentions: Using fibroblasts as model cells, the number of cells per capsules was optimized by varying the cell number against a fixed volume of hydrogel matrix. Three different cell concentrations (2,000,000; 4,000,000; and 8,000,000 cells·mL−1) were used for encapsulation within agarose-gelatin-fibrinogen matrices (Figure 2A–C). The encapsulated cells, also referred to as “cell capsules” were collected and subsequently filtered twice with cell sieves having diameter of 40 µm and 100 µm. With this technique, we are able to prepare cell capsules with a relatively narrow size distribution with ~80% of the cell capsules ranging from 20 to 70 µm in diameter (Figure 2D). It is noticed that cell capsules prepared by more complex hydrogel mixture (i.e., the agarose, agarose-gelatin and agarose-gelatin-fibrinogen mixture) will result in broaden of the capsule size distribution curve. The broadening of the capsule size distribution could be explained by the increase of the viscosity of the hydrogel mixture, which leads to the formation of less homogenous droplet during the fabrication process. The cell number(s) per single capsule as a function of various initial cell concentrations were calculated based on cell counting of individual capsules (n = 220). Figure 2E shows that the cell density per capsule increased as the initial cell concentration increased. Cell capsules prepared with an initial cell concentration of 2,000,000 cells mL−1 had highest population of singly encapsulated cells, while increasing the initial cell concentration to 4,000,000 cells·mL−1 and 8,000,000 cells mL−1 resulted in a higher proportion of capsules containing multiple cells. Hence, in order to achieve single cell encapsulation, an initial cell concentration of 2,000,000 cells·mL−1 was selected for preparation of the cell capsules. However, it is important to note that the proportion of empty capsules increased with a lower initial cell density, due to the Poisson distribution of cells.


Controlled Delivery of Human Cells by Temperature Responsive Microcapsules.

Mak WC, Olesen K, Sivlér P, Lee CJ, Moreno-Jimenez I, Edin J, Courtman D, Skog M, Griffith M - J Funct Biomater (2015)

Light micrographs showing cell capsules prepared with various initial cell concentrations (A) 2,000,000, (B) 4,000,000 and (C) 8,000,000 cells·mL−1, respectively. (D) Size distribution of capsules prepared with various hydrogel formulation. (E) Cell number(s) per single capsule (as a function of various initial cell concentrations).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493523&req=5

jfb-06-00439-f002: Light micrographs showing cell capsules prepared with various initial cell concentrations (A) 2,000,000, (B) 4,000,000 and (C) 8,000,000 cells·mL−1, respectively. (D) Size distribution of capsules prepared with various hydrogel formulation. (E) Cell number(s) per single capsule (as a function of various initial cell concentrations).
Mentions: Using fibroblasts as model cells, the number of cells per capsules was optimized by varying the cell number against a fixed volume of hydrogel matrix. Three different cell concentrations (2,000,000; 4,000,000; and 8,000,000 cells·mL−1) were used for encapsulation within agarose-gelatin-fibrinogen matrices (Figure 2A–C). The encapsulated cells, also referred to as “cell capsules” were collected and subsequently filtered twice with cell sieves having diameter of 40 µm and 100 µm. With this technique, we are able to prepare cell capsules with a relatively narrow size distribution with ~80% of the cell capsules ranging from 20 to 70 µm in diameter (Figure 2D). It is noticed that cell capsules prepared by more complex hydrogel mixture (i.e., the agarose, agarose-gelatin and agarose-gelatin-fibrinogen mixture) will result in broaden of the capsule size distribution curve. The broadening of the capsule size distribution could be explained by the increase of the viscosity of the hydrogel mixture, which leads to the formation of less homogenous droplet during the fabrication process. The cell number(s) per single capsule as a function of various initial cell concentrations were calculated based on cell counting of individual capsules (n = 220). Figure 2E shows that the cell density per capsule increased as the initial cell concentration increased. Cell capsules prepared with an initial cell concentration of 2,000,000 cells mL−1 had highest population of singly encapsulated cells, while increasing the initial cell concentration to 4,000,000 cells·mL−1 and 8,000,000 cells mL−1 resulted in a higher proportion of capsules containing multiple cells. Hence, in order to achieve single cell encapsulation, an initial cell concentration of 2,000,000 cells·mL−1 was selected for preparation of the cell capsules. However, it is important to note that the proportion of empty capsules increased with a lower initial cell density, due to the Poisson distribution of cells.

Bottom Line: However, its full potential is limited by the rapid loss of introduced therapeutic cells before their full effects can be exploited, due in part to anoikis, and in part to the adverse environments often found within the pathologic tissues that the cells have been grafted into.Cell encapsulation and controlled release was demonstrated using human fibroblasts as model cells, as well as a therapeutically relevant cell line-human umbilical vein endothelial cells (HUVECs).While such temperature responsive cell microcapsules promise effective, controlled release of potential therapeutic cells at physiological temperatures, further work will be needed to augment the composition of the microcapsules and optimize the numbers of cells per capsule prior to clinical evaluation.

View Article: PubMed Central - PubMed

Affiliation: Integrative Regenerative Medicine Centre, Department of Clinical and Experimental Medicine, Linköping University, SE58185, Linköping, Sweden. mamak@ifm.liu.se.

ABSTRACT
Cell therapy is one of the most promising areas within regenerative medicine. However, its full potential is limited by the rapid loss of introduced therapeutic cells before their full effects can be exploited, due in part to anoikis, and in part to the adverse environments often found within the pathologic tissues that the cells have been grafted into. Encapsulation of individual cells has been proposed as a means of increasing cell viability. In this study, we developed a facile, high throughput method for creating temperature responsive microcapsules comprising agarose, gelatin and fibrinogen for delivery and subsequent controlled release of cells. We verified the hypothesis that composite capsules combining agarose and gelatin, which possess different phase transition temperatures from solid to liquid, facilitated the destabilization of the capsules for cell release. Cell encapsulation and controlled release was demonstrated using human fibroblasts as model cells, as well as a therapeutically relevant cell line-human umbilical vein endothelial cells (HUVECs). While such temperature responsive cell microcapsules promise effective, controlled release of potential therapeutic cells at physiological temperatures, further work will be needed to augment the composition of the microcapsules and optimize the numbers of cells per capsule prior to clinical evaluation.

No MeSH data available.


Related in: MedlinePlus