BIOSEPARATION COMPOSITIONS AND METHODS FOR MAKING AND USING SAME

1 . A composition for use in bioseparation, the composition comprising:

a plurality of hollow particles, the hollow particles comprising a siliceous surface; and

a surface-modifying agent bonded to the hollow particles, wherein the surface-modifying agent comprises a binding segment and a reactive segment, wherein the binding segment comprises a silyl group, and wherein the reactive segment comprises a reactive nitrogen group;

wherein the plurality of hollow particles have an average density between about 0.05 and 0.4 g/ml.

2 . The composition according to claim 1 , wherein the hollow particles comprise glass bubbles.

3 . The composition according to claim 1 , wherein a size distribution of the plurality of hollow particles has a span of less than 1.0.

4 . The composition of claim 1 , wherein a mean particle size of the plurality of hollow particles ranges from about 10 micrometers to about 100 micrometers.

5 . The composition of claim 1 , wherein the binding segment has a formula:

—Si(R 1 ) 3-x (R 2 ) x ;

wherein x=0, 1, or 2;

wherein each group R 1 comprises independently OH − or a hydrolyzable group from among halo, alkoxy, aryloxy, aralkyoxy, and acyloxy; and

wherein each group R 2 comprises independently a non-hydrolyzable group from among alkyl, aryl, and aralkyl.

6 . The composition of claim 1 , wherein the surface-modifying agent further comprises a linking segment, the linking segment comprising alkylene, arylene, or both, and optionally further comprising —NH— or alkyleneoxy, or both.

7 . The composition of claim 1 , wherein the reactive segment has a formula:

—N(R 3 ) 2 , or salts thereof;

wherein each group R 3 comprises independently hydrogen, alkyl, aryl, or aralkyl.

8 . A method for making a bioseparation composition, the method comprising:

size fractionating a first plurality of hollow particles having a first particle size distribution with a first span to form a second plurality of hollow particles having a second particle size distribution with a second span that is less than the first span; and

surface-modifying either or both of the first and second plurality of hollow particles with a surface modifying agent to form surface-modified hollow particles, wherein the surface-modifying agent comprises a binding segment and a reactive segment, wherein the binding segment comprises a silyl group, and wherein the reactive segment comprises a reactive nitrogen group.

9 . The method of claim 8 , wherein the first and second plurality of hollow particles comprise glass bubbles.

10 . The method of claim 8 , wherein the second span is less than 1.0.

11 . The method of claim 8 , wherein a mean particle size of the second plurality of hollow particles ranges from about 10 micrometers to about 100 micrometers.

12 . The method of claim 8 , wherein the binding segment has a formula:

—Si(R 1 ) 3-x (R 2 ) x ;

wherein x=0, 1, or 2;

wherein each group R 1 comprises independently OH − or a hydrolyzable group from among halo, alkoxy, aryloxy, aralkyoxy, and acyloxy; and

wherein each group R 2 comprises independently a non-hydrolyzable group from among alkyl, aryl, and aralkyl.

13 . The method of claim 8 , wherein the surface-modifying agent further comprises a linking segment, the linking segment comprising alkylene, arylene, or both, and optionally further comprising —NH— or alkyleneoxy, or both.

14 . The method of claim 8 , wherein the reactive segment has a formula:

—N(R 3 ) 2 , or salts thereof;

wherein each group R 3 comprises independently hydrogen, alkyl, aryl, or aralkyl.

15 . A method for capturing an analyte the method comprising:

providing a bioseparation composition comprising:

a plurality of hollow particles; and

a surface-modifying agent bonded to the hollow particles, wherein the surface-modifying agent comprises a binding segment and a reactive segment, wherein the binding segment comprises a silyl group, and wherein the reactive segment comprises a reactive nitrogen group;

wherein the plurality of hollow particles have an average density between about 0.05 and 0.4 g/ml; and

contacting the bioseparation composition with a solution comprising an analyte, wherein the surface-modifying agent is capable of coupling to the analyte.

16 . The method of claim 15 , further comprising separating the bioseparation composition from the solution.

17 . The method of claim 16 , wherein separating the bioseparation composition from the solution comprises allowing the bioseparation composition to float to an upper surface of the solution.

18 . The method of claim 15 , wherein the hollow particles comprise glass bubbles.

19 . The method of claim 15 , wherein a size distribution of the plurality of hollow particles has a span of less than 1.0.