Senior Research Associate/ Research Associate - protein purification

Celltheon Corporation; San Francisco (CA); On-site; USD 90,000 - 140,000; Full time

Job summary

Celltheon Corporation in San Francisco, CA is seeking a Senior Research Associate / Research Associate– Protein Purification to join our downstream process development team. This hands-on role focuses on developing, optimizing, and scaling purification processes for recombinant proteins, monoclonal antibodies, bispecifics, Fc-fusions, and other biologics.

You will work closely with scientists across molecular biology, cell line development, upstream process development, and analytics to support

Qualifications

• Degree in biotechnology, biochemistry, chemical engineering or bioprocessing.
• 2–3 years of industry experience in protein purification or downstream development.
• Hands-on experience with ÄKTA FPLC systems.
• Familiarity with TFF systems and analytical HPLC methods.
• Experience purifying recombinant proteins and monoclonal antibodies.

Responsibilities

• Develop and optimize protein purification processes using chromatography.
• Design and execute purification workflows for recombinant proteins and monoclonal antibodies.
• Perform tangential flow filtration for concentration and buffer exchange.
• Operate, maintain, and troubleshoot ÄKTA FPLC systems.
• Document experiments in ELNs, batch records, and SOPs.
• Collaborate with cross-functional teams across development stages.
• Maintain lab equipment and ensure safety and quality procedures.

Skills

Protein purification

Downstream process

Troubleshooting

Documentation

Team collaboration

Education

BSc/MSc Life Sciences

Tools

ÄKTA FPLC systems

TFF systems

Unicorn software

HPLC/SEC

Job description

Job Type: Full-Time | Onsite

Join Celltheon and Help Develop the Next Generation of Biologics

Celltheon Corporation is seeking an experienced Senior Research Associate / Research Associate– Protein Purification to join our downstream process development team. This hands-on laboratory position offers the opportunity to develop, optimize, and scale purification processes for recombinant proteins, monoclonal antibodies, bispecific antibodies, Fc-fusion proteins, and other biologics.

Working closely with scientists across molecular biology, cell line development, upstream process development, and analytics, you will support projects from early research through process development.

Key Responsibilities

• Develop and optimize protein purification processes using Protein A, ion exchange (CEX/AEX), hydrophobic interaction (HIC), mixed-mode, IMAC, and size exclusion chromatography (SEC).
• Design and execute purification workflows for recombinant proteins and monoclonal antibodies.
• Perform tangential flow filtration (TFF) for protein concentration, buffer exchange, and formulation.
• Operate, maintain, and troubleshoot ÄKTA FPLC systems.
• Perform routine analytical assays including:
• SEC-HPLC
• CEX-HPLC
• SDS-PAGE
• UV protein concentration measurements
• Endotoxin testing
• Analyze purification data and recommend process improvements.
• Prepare buffers, chromatography columns, reagents, and laboratory solutions.
• Document experiments in electronic laboratory notebooks (ELNs), batch records, and SOPs.
• Collaborate with cross-functional teams to support client and internal development projects.
• Maintain laboratory equipment and follow laboratory safety and quality procedures.

Qualifications

• Bachelor's / Master’s degree in Biotechnology, Biochemistry, Chemical Engineering, Bioprocess Engineering, or a related life science discipline.
• 2-3 years of industry experience in protein purification or downstream process development.
• Strong hands‑on experience operating ÄKTA FPLC systems.
• Experience with TFF systems is highly desirable.
• Familiarity with analytical HPLC methods, especially SEC and ion exchange chromatography.
• Experience purifying recombinant proteins and monoclonal antibodies.
• Strong troubleshooting, organizational, and documentation skills.
• Ability to work independently and collaboratively in a fast‑paced team environment.

Preferred Qualifications

• Experience with process development and purification optimization.
• Familiarity with Unicorn software and chromatography data analysis.
• Experience supporting process scale‑up and technology transfer.