Polymeric surface having reduced biomolecule adhesion to thermoplastic articles of such substrate

1. A method of forming a microplate consisting essentially of a fluid contact surface and an interior portion, the interior portion being polypropylene or polystyrene, and the fluid contact surface comprising:

from 1 to 30 atomic %, optionally from 5 to 20 atomic %, optionally from 5 to 10 atomic %, grafted oxygen atoms,

from 0 to 30 atomic %, optionally from 0 to 20 atomic %, optionally from 0 to 10 atomic %, grafted nitrogen atoms, and

from 70 to 99 atomic %, optionally from 80 to 95 atomic %, optionally from 90 to 95 atomic %, carbon atoms,

in which the atomic % values are measured by x-ray photoelectron spectroscopy (XPS); and

in which the fluid contact surface has a biomolecule recovery percentage of at least 85% after 24 hours;

the method comprising:

providing a microplate; and

treating the fluid contact surface with a conditioning plasma comprising oxygen followed by a conversion plasma comprising water vapor;

in which the conversion plasma is generated at a remote point from the fluid contact surface, where a ratio of radiant energy density at the fluid contact surface to radiant energy density at a brightest point of the conversion plasma is less than 0.5.

2. The method of claim 1 , wherein a ratio of radiant energy density at the fluid contact surface to radiant energy density at a brightest point of the conversion plasma is less than 0.25.

3. The method of claim 2 , wherein a ratio of radiant energy density at the fluid contact surface to radiant energy density at a brightest point of the conversion plasma is substantially zero.

4. The method of claim 3 , wherein a ratio of radiant energy density at the fluid contact surface to radiant energy density at a brightest point of the conversion plasma is zero.

5. The method of claim 1 , wherein the fluid contact surface has a biomolecule recovery percentage of at least 90% after 24 hours.

6. The method of claim 1 , wherein the biomolecule recovery percentage is determined for at least one of: mammal serum albumin; bovine serum albumin (BSA); fibrinogen (FBG); transferrin (TFN); egg white ovotransferrin (conalbumin); membrane-associated melanotransferrin; protein A (PrA); protein G (PrG); protein A/G; protein L; insulin; pharmaceutical protein; blood or blood component proteins; and any recombinant form, modification, full length precursor, signal peptide, propeptide, or mature variant of these proteins.

7. The method of claim 1 , wherein the biomolecule recovery percentage is determined for at least one of: bovine serum albumin (BSA), protein A (PrA), or protein G (PrG).

8. The method of claim 7 , in which the biomolecule recovery percentage is determined at a concentration between 1.5 nM and 6 nM.

9. The method of claim 7 , in which the contact surface also has a biomolecule recovery percentage of at least 85% after 3 months.

10. The method of claim 1 , wherein any one or more of the following is true:

for an aqueous dispersion of lyophilized BSA having an atomic mass of 66,000 Daltons at a concentration of 12 nM, the biomolecule recovery percentage of the fluid contact surface is at least 99% after 30 minutes;

for an aqueous dispersion of lyophilized FBG having an atomic mass of 340,000 Daltons at a concentration of 12 nM, the biomolecule recovery percentage of the fluid contact surface is at least 98% after 30 minutes;

for an aqueous dispersion of lyophilized TFN having an atomic mass of 80,000 Daltons at a concentration of 12 nM, the biomolecule recovery percentage of the fluid contact surface is at least 90% after 30 minutes;

for an aqueous dispersion of lyophilized PrA having an atomic mass of 45,000 Daltons at a concentration of 12 nM, the biomolecule recovery percentage of the fluid contact surface is at least 99% after 30 minutes.

11. The method of claim 1 , in which the microplate is a 96-well plate or a 384-well plate.

12. The method of claim 1 , in which the microplate is an enzyme-linked immunosorbent assay plate.