# US 11,999,929 B2 · Methods and systems for coating a cell growth surface > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,999,929 B2 - Document ID: US11999929B2 - Status: Granted - Kind: B2 - Application number: 16/845,686 - Filed: 2020-04-10 - Published: 2020-07-30 - Granted: 2024-06-04 - Earliest claimed: 2016-06-07 - Assignees: Terumo BCT, Inc. - Applicants: Terumo BCT, Inc. - Inventors: Nathan D. Frank; Brian J. Nankervis; Dennis J. Hlavinka; Thomas G. Dilorenzo - Web page: https://patentgrep.com/patent/US11999929B2 ## CPC - C12M 1/005: {Incubators} - C12M 21/00: {Bioreactors or fermenters specially adapted for specific uses (digesters for manure A01C3/023; apparatus for PCR B01L7/52; destroying or transforming solid waste B09B3/00; methods for genetic engineering C12N15/00, C12Q1/68; nucleic acid amplification reactions C12Q1/6844)} - C12M 23/06: {Tubular (C12M23/08, C12M23/16 take precedence)} - C12M 23/16: {Microfluidic devices; Capillary tubes (integrated microfluidic structures B01L3/5027; microreactors B01J19/0093)} - C12M 23/20: {Material Coatings (immunocoatings C12M25/00)} - C12M 25/02: {Membranes; Filters (filters or filtration in general B01D24/00-B01D41/00)} - C12M 25/12: {the culture medium flowing outside the fiber or tube} - C12M 29/04: {Filters; Permeable or porous membranes or plates, e.g. dialysis} - C12M 29/18: {External loop; Means for reintroduction of fermented biomass or liquid percolate (loop type reactors for chemical or physical processes B01J19/2435)} - C12M: APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; {APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS} ## Abstract Embodiments described herein generally provide for the expansion of cells in a cell expansion system using an active promotion of a coating agent(s) to a cell growth surface. A coating agent may be applied to a surface, such as the cell growth surface of a hollow fiber, by controlling the movement of a fluid in which a coating agent is suspended. Using ultrafiltration, the fluid may be pushed through the pores of a hollow fiber from a first side, e.g., an intracapillary (IC) side, of the hollow fiber to a second side, e.g., an extracapillary (EC) side, while the coating agent is actively promoted to the surface of the hollow fiber. In so doing, the coating agent may be hydrostatically deposited onto a wall, e.g., inner wall, of the hollow fiber. ## Claims ### Claim 1 A method of applying an agent to a cell growth surface in a cell expansion system, the method comprising: loading the agent and a fluid into the cell expansion system; conducting a first wash at a first inlet flow rate to push the agent and the fluid into a circulation loop; closing an outlet to the circulation loop; and after the closing, conducting a second wash at a second inlet flow rate higher than the first inlet flow rate to force a portion of the fluid through pores in a wall of the circulation loop and hydrostatically deposit the agent on the cell growth surface of the wall. ### Claim 2 (depends on 1) The method of claim 1, wherein the agent comprises cryoprecipitate. ### Claim 3 (depends on 1) The method of claim 1, wherein conducting the first wash further comprises: pushing the agent from an air removal chamber into the circulation loop. ### Claim 4 (depends on 3) The method of claim 3, wherein the circulation loop comprises an intracapillary loop. ### Claim 5 (depends on 4) The method of claim 4, wherein the cell expansion system comprises a hollow fiber bioreactor, and wherein the hollow fiber bioreactor comprises a plurality of hollow fibers. ### Claim 6 (depends on 5) The method of claim 5, wherein each of the plurality of hollow fibers comprises the cell growth surface. ### Claim 7 (depends on 5) The method of claim 5, wherein, during the second wash, the fluid is actively moved from an intracapillary (IC) side of the hollow fiber bioreactor to an extracapillary (EC) side of the hollow fiber bioreactor by closing an IC outlet valve and opening an EC outlet valve, and wherein the agent remains on at least a portion of the plurality of the hollow fibers while the fluid is pushed to the EC side from the IC side. ### Claim 8 (depends on 7) The method of claim 7, wherein the agent is hydrostatically deposited onto an inner wall of the IC side of each of the plurality of hollow fibers. ### Claim 9 (depends on 1) The method of claim 1, wherein the conducting the second wash is performed for a duration ranging from 5 minutes to 60 minutes. ### Claim 10 A method for rapidly coating a cell growth surface in a cell expansion system, the method comprising: priming the cell expansion system, wherein the cell expansion system comprises: a bioreactor, wherein the bioreactor comprises: a hollow fiber membrane having an intracapillary portion and an extracapillary portion, wherein the hollow fiber membrane comprises a plurality of hollow fibers, the plurality of hollow fibers comprising a cell growth surface; a first fluid flow path having a first inlet and a first outlet at at least opposing ends of the bioreactor, wherein the first fluid flow path is fluidly associated with the intracapillary portion of the hollow fiber membrane; a second fluid flow path having a second inlet and a second outlet, wherein the second fluid flow path is fluidly associated with the extracapillary portion of the hollow fiber membrane; a first connection port fluidly associated with the first fluid flow path; a first outlet valve fluidly associated with the first fluid flow path; a second outlet valve fluidly associated with the second fluid flow path; and a harvest bag; connecting a first bag containing a solution including a fluid and a reagent for coating the cell growth surface of the plurality of hollow fibers; closing the first outlet valve; opening the second outlet valve; flowing the solution into the first fluid flow path; conducting a first wash by flowing a second fluid into the first flow path at a first inlet flow rate; conducting a second wash by flowing the second fluid into the first flow path at a second inlet flow rate greater than the inlet first flow rate for a duration, thereby coating, through ultrafiltration, the cell growth surface with the reagent; connecting a second bag to the first connection port to introduce cells to the bioreactor; feeding the cells; connecting the harvest bag to the first fluid flow path to harvest the cells; and harvesting the cells into the harvest bag. ### Claim 11 (depends on 7) The method of claim 7, wherein the fluid includes phosphate buffered saline. ### Claim 12 (depends on 10) The method of claim 10, wherein the first fluid and the second fluid include phosphate buffered saline. ### Claim 13 (depends on 10) The method of claim 10, wherein the reagent includes cryoprecipitate (CPPT), fibronectin (FN), or a combination of CPPT and FN. ### Claim 14 (depends on 9) The method of claim 9, wherein the duration is 10 minutes or less. ### Claim 15 (depends on 1) The method of claim 1, wherein the second inlet flow rate ranges from 40 mL/min to 60 mL/min.