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Freely suspended cellular "backpacks" lead to cell aggregate self-assembly.

Swiston AJ, Gilbert JB, Irvine DJ, Cohen RE, Rubner MF - Biomacromolecules (2010)

Bottom Line: Cellular "backpacks" are a new type of anisotropic, nanoscale thickness microparticle that may be attached to the surface of living cells creating a "bio-hybrid" material.Previous work has shown that these backpacks do not impair cell viability or native functions such as migration in a B and T cell line, respectively.In the current work, we show that backpacks, when added to a cell suspension, assemble cells into aggregates of reproducible size.

View Article: PubMed Central - PubMed

Affiliation: Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.

ABSTRACT
Cellular "backpacks" are a new type of anisotropic, nanoscale thickness microparticle that may be attached to the surface of living cells creating a "bio-hybrid" material. Previous work has shown that these backpacks do not impair cell viability or native functions such as migration in a B and T cell line, respectively. In the current work, we show that backpacks, when added to a cell suspension, assemble cells into aggregates of reproducible size. We investigate the efficiency of backpack-cell binding using flow cytometry and laser diffraction, examine the influence of backpack diameter on aggregate size, and show that even when cell-backpack complexes are forced through small pores, backpacks are not removed from the surfaces of cells.

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Examples of how some d = 15 μm backpacks curl upon themselves: (a) a cylindrical folding; (b) a “tricorne”-like shape. Scale bar is 10 μm.
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fig6: Examples of how some d = 15 μm backpacks curl upon themselves: (a) a cylindrical folding; (b) a “tricorne”-like shape. Scale bar is 10 μm.

Mentions: As can be seen in Figure 3, FITChigh events have two distinct populations differing by a factor of 2 in FSC intensity. This reflects single cells with a backpack or small aggregates with one or more backpacks associated. Figure 5 shows the percentage of FITChighFSClow (single cells with a backpack) and FITChighFSChigh (small clusters) events, as well as the sum, for both d = 7 and 15 μm. For d = 7 μm, at R = 10, 3% of cells are associated with a backpack; at R = 0.1, 65% of events include a backpack. When the diameter increases to 15 μm, the highest number of cells with an attached backpack decreases to 46%. While this might reflect slight differences in sample handling, it is more likely that this decrease is due to curling of some backpacks upon themselves, thus, reducing the total surface area available to strongly bind. Examples of how d = 15 μm backpacks fold are seen in Figure 6. This curling behavior was not observed for d = 7 μm backpacks, suggesting some critical size required for folding.


Freely suspended cellular "backpacks" lead to cell aggregate self-assembly.

Swiston AJ, Gilbert JB, Irvine DJ, Cohen RE, Rubner MF - Biomacromolecules (2010)

Examples of how some d = 15 μm backpacks curl upon themselves: (a) a cylindrical folding; (b) a “tricorne”-like shape. Scale bar is 10 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2903013&req=5

fig6: Examples of how some d = 15 μm backpacks curl upon themselves: (a) a cylindrical folding; (b) a “tricorne”-like shape. Scale bar is 10 μm.
Mentions: As can be seen in Figure 3, FITChigh events have two distinct populations differing by a factor of 2 in FSC intensity. This reflects single cells with a backpack or small aggregates with one or more backpacks associated. Figure 5 shows the percentage of FITChighFSClow (single cells with a backpack) and FITChighFSChigh (small clusters) events, as well as the sum, for both d = 7 and 15 μm. For d = 7 μm, at R = 10, 3% of cells are associated with a backpack; at R = 0.1, 65% of events include a backpack. When the diameter increases to 15 μm, the highest number of cells with an attached backpack decreases to 46%. While this might reflect slight differences in sample handling, it is more likely that this decrease is due to curling of some backpacks upon themselves, thus, reducing the total surface area available to strongly bind. Examples of how d = 15 μm backpacks fold are seen in Figure 6. This curling behavior was not observed for d = 7 μm backpacks, suggesting some critical size required for folding.

Bottom Line: Cellular "backpacks" are a new type of anisotropic, nanoscale thickness microparticle that may be attached to the surface of living cells creating a "bio-hybrid" material.Previous work has shown that these backpacks do not impair cell viability or native functions such as migration in a B and T cell line, respectively.In the current work, we show that backpacks, when added to a cell suspension, assemble cells into aggregates of reproducible size.

View Article: PubMed Central - PubMed

Affiliation: Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.

ABSTRACT
Cellular "backpacks" are a new type of anisotropic, nanoscale thickness microparticle that may be attached to the surface of living cells creating a "bio-hybrid" material. Previous work has shown that these backpacks do not impair cell viability or native functions such as migration in a B and T cell line, respectively. In the current work, we show that backpacks, when added to a cell suspension, assemble cells into aggregates of reproducible size. We investigate the efficiency of backpack-cell binding using flow cytometry and laser diffraction, examine the influence of backpack diameter on aggregate size, and show that even when cell-backpack complexes are forced through small pores, backpacks are not removed from the surfaces of cells.

Show MeSH