Limits...
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.

Show MeSH
Confocal microscopy images of ways B cells attached to backpacks using the injectable backpack protocol. (a) How a 7 μm backpack may attach to several cells and (b) how each cell may bind to more than one backpack. Scale bar is 10 μm, and R = 10 for both aliquots. The green fluorescence signal is from the DiO sprayed with PLGA.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2903013&req=5

fig2: Confocal microscopy images of ways B cells attached to backpacks using the injectable backpack protocol. (a) How a 7 μm backpack may attach to several cells and (b) how each cell may bind to more than one backpack. Scale bar is 10 μm, and R = 10 for both aliquots. The green fluorescence signal is from the DiO sprayed with PLGA.

Mentions: An “injectable” backpack formulation, however, leads to cell−backpack aggregates. These aggregates contain any number of cells and backpacks, and the factors influencing the order of these aggregates include the number of cells per backpack and the number of backpacks attached to each cell. Nonconformal attachment can occur due to curvature of the flexible backpack; an overhanging portion of the backpack may then bind to one or more cells. An example is shown in Figure 2a, where three cells attached to a single backpack. When a single cell is associated with more than one backpack, and each backpack may attach multiple cells, aggregates form. Figure 2b shows one of the lowest order aggregates that may form, where one cell has two backpacks and each backpack has three cells attached. Each of these micrographs shows cells exposed to backpacks for ∼1.5 h, and no evidence of internalization was ever observed. (In fact, when backpacks are exposed to a macrophage cell line known to quickly internalize spherical particles several micrometers in diameter, we see very little backpack internalization. This is the subject of ongoing investigation and will be featured in an up-coming publication.)


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

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

Confocal microscopy images of ways B cells attached to backpacks using the injectable backpack protocol. (a) How a 7 μm backpack may attach to several cells and (b) how each cell may bind to more than one backpack. Scale bar is 10 μm, and R = 10 for both aliquots. The green fluorescence signal is from the DiO sprayed with PLGA.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig2: Confocal microscopy images of ways B cells attached to backpacks using the injectable backpack protocol. (a) How a 7 μm backpack may attach to several cells and (b) how each cell may bind to more than one backpack. Scale bar is 10 μm, and R = 10 for both aliquots. The green fluorescence signal is from the DiO sprayed with PLGA.
Mentions: An “injectable” backpack formulation, however, leads to cell−backpack aggregates. These aggregates contain any number of cells and backpacks, and the factors influencing the order of these aggregates include the number of cells per backpack and the number of backpacks attached to each cell. Nonconformal attachment can occur due to curvature of the flexible backpack; an overhanging portion of the backpack may then bind to one or more cells. An example is shown in Figure 2a, where three cells attached to a single backpack. When a single cell is associated with more than one backpack, and each backpack may attach multiple cells, aggregates form. Figure 2b shows one of the lowest order aggregates that may form, where one cell has two backpacks and each backpack has three cells attached. Each of these micrographs shows cells exposed to backpacks for ∼1.5 h, and no evidence of internalization was ever observed. (In fact, when backpacks are exposed to a macrophage cell line known to quickly internalize spherical particles several micrometers in diameter, we see very little backpack internalization. This is the subject of ongoing investigation and will be featured in an up-coming publication.)

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