Principal Scientist, ADCs

About Us:

Ridge Biotechnologies enables the development and construction of the next generation of precision medicines through enzyme and targeted therapeutic design. Using our powerful experimental and computational platform built on large datasets generated by cell-free synthesis, biorthogonal chemistries, and ever-improving machine learning models, Ridge is pioneering the design of new medicines and scalable production methods that enable our partners to bring life-saving therapies to patients in need. In recent months, we've secured multiple partnerships and launched our first product lines: NativeLink enzymes that provide precise and stable bioconjugation without modification of protein sequence, glycan, or disulfide bonds; ProTrigger protease-cleavable linkers that enable selective drug release in the tumor microenvironment; and novel enzyme-based Catalytic Medicines.

Ridge Bio's founders are industry veterans who have previously built successful biotechnology companies and academic leaders from top institutions including Stanford and Caltech with world-leading expertise in cell-free systems, therapeutic development, and protein engineering. We are backed by Sutter Hill Ventures, a quiet powerhouse that has been building successful companies since 1962 by focusing on bringing together great people to solve hard technological problems in big markets. Our company culture is dedicated to intellectual integrity, service ownership, and creative impact.

Role Description:

We are looking for an experienced, hands-on antibody scientist with deep expertise in antibody discovery, characterization, and antibody drug conjugate (ADC) development to join our team. In this role, you'll develop and implement drug discovery workflows for our partners' assets from initial characterization through in vitro proof-of-concept, and serve as our in-house expert on antibody function and ADC biology as we apply NativeLink and ProTrigger challenging targets. You'll spend the majority of your time at the bench: building cell lines, running binding and functional assays, and generating the data packages that help our partners drive molecules to the clinic and continue to prove out and expand the applications of our technology. Your work will be highly collaborative, combining your expertise with that of top scientists across enzyme design, high-throughput experimentation, machine learning, and bioconjugation chemistry. An appetite for taking on new challenges and techniques, working flexibly across disciplines, and delivering value for our partners through a pragmatic, get-it-done approach to drug discovery are a must. As we grow, you'll help shape our antibody and in vitro biology strategy, advance assets across a range of indications, and mentor scientists throughout the team. Level and compensation will be set by experience and previously demonstrated impact in highly related research.

Required Qualifications:

- Completed a Ph.D. in immunology, cell biology, molecular biology, or a related discipline. Successful applicants will have many additional years (10+) of highly relevant drug discovery experience and be recognized experts in antibody development as well as oncology and immunology.

- Direct, hands-on experience across the full antibody development life cycle — including monoclonal antibody generation and screening, binding and functional characterization, humanization, affinity maturation, and developability assessment.

- Direct experience developing and constructing antibody drug conjugates (ADCs),

- Demonstrated ability to build and run cell-based assays — including cytotoxicity, cell killing, phagocytosis, proliferation, and cytokine release assays — to functionally characterize antibodies and antibody drug conjugates against complex antigen targets.

- Hands-on molecular and cellular skills including cell line transduction and construction, gene cloning and expression vector design, flow cytometry, and ELISA based assays — with the ability to independently stand up new assays and models rather than relying solely on support staff.

- Direct experience designing and running ELISAs to support antibody screening, binding characterization, and quantitation across discovery and development programs.

- Broad drug discovery experience across multiple programs, from target validation through candidate selection and IND-enabling studies, with the judgment to know which experiments matter most to move a program forward.

- Experience planning and executing animal studies.

- Managing external CROs and vendors to supplement internal bench capacity.

- A genuine preference for working at the bench and staying close to the data, paired with the scientific leadership to help define data package strategy.

- Experience mentoring and training junior scientists to build a strong technical team.

- Ability to work full-time hours at our Bay Area location in San Carlos and occasional flexibility to travel and complete time-sensitive projects.

How you'll contribute:

- Serve as our in-house expert on antibody biology and ADC development as we apply NativeLink and ProTrigger to our partners' antibody and antigen targets.

- Take ownership of incoming partner antibodies — building our antibody libraries, standing up cell-based binding and functional assays, and constructing the in vitro models needed to characterize antibodies against complex, novel antigen targets.

- Build and run cell-line transduction, antibody production, and characterization capabilities in-house.

- Design and execute the functional and biophysical experiments — including cell kill assays and antibody characterization studies and help shape the resulting data package for partners and investors.

- Partner closely with our platform team to connect biology insights to enzyme and linker design, helping prioritize molecules.

- Manage CRO relationships and external collaborations to supplement internal capacity.

- Mentor and train junior team members in antibody characterization and in vitro biology techniques.

- Work with our founding team to develop and define the company's technical development roadmap to meet urgent customer and patient needs.

We offer a strong benefits package, competitive compensation, and an opportunity to work collaboratively with a top-notch team with diverse skillsets to solve challenging problems with wide impact in therapeutics. If you're a master at your craft of antibody and ADC development and are looking to apply your skills to solve important problems faced by therapeutic developers as part of a fast-paced, team-based, and entrepreneurial environment, then this job is for you!