Preclinical Assays Scientist (SRA/Associate Sci/Scientist 1)

San Francisco
Preclinical Discovery /
Full time /
The fight against cancer needs new, big, bold ideas. At Siren, we’ve got one: Universal AAV Immuno-Gene Therapy. We are combining two transformative therapeutic technologies – AAV gene therapy and cytokine immunotherapy - into a single, reimagined modality that overcomes key challenges and redefines how we destroy tumor cells and elicit anti-tumor immunity. We're looking for a Senior Research Associate/Associate Scientist/Scientist I (title dependent on experience) to join our team in developing and performing unique in vitro assays for new and innovative AAV immuno-gene therapies.

Position Description
Siren Biotechnology is seeking a highly motivated Preclinical Research Scientist (title dependent on experience) to join our Preclinical Research team and help work to advance our gene therapy candidates towards IND. This position is the keeper of Siren’s preclinical assay toolbox and a key contributor to preclinical studies. The successful candidate will support gene therapy research programs by providing advanced assay development expertise, with a primary focus on developing cell-based and in vitro assays. This role will also be responsible for downstream analysis of in vivo cell/tissue samples from pharmacology and biodistribution experiments. You will work closely with a stellar team of AAV and pharmacology experts to drive multiple innovative research projects and your impact will be felt at Siren directly: as a research scientist, your efforts to characterize the mechanism of action, distribution, and retention of our AAV gene therapies will be used continuously to guide our translation to the clinic.

This is an in-person wet lab role at our Mission Bay San Francisco laboratory and is not eligible for remote or hybrid work schedules.

About Siren
Our name, Siren Biotechnology, was inspired by the powerful signal our AAV immuno-gene therapy sends to the immune system, stimulating an immediate anti-tumor response.
We’re sounding the alarm against cancer!

Our vision is to revolutionize cancer treatment by making Siren's AAV immuno-gene therapy the cornerstone treatment for any solid tumor. It will take a diverse and capable team to create the world's first universal AAV immuno-gene therapy for cancer. Our team is growing, and we’d love to meet you.

We at Siren Biotechnology offer a unique working environment within the heart of Mission Bay in San Francisco. Our lab and offices are situated within a beautiful urban campus immediately next to UCSF Mission Bay. We have easy access to a range of educational, cultural, and recreational activities including Spark Social, Parklab Gardens, Thrive City, and the waterfront!

Want to learn more? Visit

See below for role responsibilities and desired qualifications.

As an SRA/Associate Scientist/Scientist I at Siren, you will:

    • Independently develop fit-for-purpose in vitro and ex vivo preclinical assays to interrogate cellular responses to treatment, biodistribution, and viral potency through methods such as ELISA/Luminex/MSD, qRT-PCR, RNAscope (in situ hybridization), IHC, qPCR, and/or dPCR. Perform additional assay method development and pre-qualification as warranted.
    • Draft SOPs for developed assays, and train team members as needed.
    • Learn and perform existing Siren SOPs for standard analysis of AAV preps (dPCR viral titer, purity via SDS-PAGE, viral capsid ELISA, and various protein expression ELISAs).
    • Perform sample analysis on key in vivo, ex vivo, and in vitro samples using established assays.
    • Support method transfers as needed to GLP-compliant CROs to enable assay method validation efforts.
    • Support method transfers to GLP and GMP-compliant CDMOs to enable assay method qualification efforts.
    • Co-own Siren’s tissue culture efforts, including maintaining cell lines (expansion & working cell bank generation) and development efforts for novel cell-based models (tumor spheroids, etc.)
    • Independently tabulate and present results and summarize findings in reports that may be used internally or externally for regulatory filings.
    • Collaborate with other internal and external teams to engineer creative solutions for dosing, sampling, and stability/material compatibility testing.
    • Participate in basic lab upkeep together with all other bench scientists, but not lead this effort.
    • Assist in logistics for outsourced projects, including preparation of viruses or samples, shipping forms, and safe parcel preparation.
    • [Bonus] Perform flow cytometry using your experience in panel design (6+ colors), machine set-up (selection of voltages and compensation), and sample acquisition and downstream analysis (FlowJo or similar).
    • [Bonus] Assist in CRO project oversight for outsourced preclinical studies including IHC method development and in vivo projects (<20% total effort)
    • Perform all activities in compliance with applicable regulations, Siren’s policies, and guidelines, including maintaining all required training.


    • BS or MS in Biology, Molecular Biology, Cell Biology, Biochemistry, or related life sciences field with 4+ years of industry experience with in vitro or molecular biology assay development is required.
    • Experience in fit-for-purpose assay development in an in vitro platform is required, but this experience can be satisfied by assay systems not described below. Familiarity with assay qualification, assay validation, and/or method transfer to external parties is a bonus.
    • Strong mammalian tissue culture expertise, impeccable aseptic technique, and comfort handling multiple cell line types. Experience with primary cell culture is a plus.
    • Experience with analytical assessment and development of AAV vectors is a plus
    • Experience with molecular biology techniques including DNA & RNA extraction, primer design, and PCR-based assay development.
    • Experience with a plate-based protein quantitation techniques (e.g. ELISA, MSD, Luminex, etc.) to the level that you can independently pilot an off-the-shelf assay. Familiarity designing unique and novel protein quantitation assays is a bonus.
    • Experience with cell-based reporter assays or similar. Familiarity designing unique and novel cell-based assays is a bonus.
    • Fluency operating in ambiguous situations with changing priorities, and flexibility to make decisions using minimal available data.
    • Adept at managing multiple commitments with accuracy and timely efficiency.
    • Strong organizational skills, attention to detail, and a proven ability to work cross-functionally.
    • Strong proficiency working with an electronic lab notebook, GraphPad Prism, Excel, PowerPoint, and Zoom is required; bonus if you have experience with Benchling, Notion, Asana, FlowJo, ImageJ/FIJI, and/or Python/R programming.
    • Demonstrated track record of clear positive communication, working with a small multidisciplinary team.
    • Must be a self-starter and team player who can thrive in an entrepreneurial environment.
    • Excellent troubleshooting skills, attention to detail, and ability to work productively in a fast-paced environment and translate technical concepts into user-friendly documentation.
    • Self-motivated and passionate about cutting-edge science and technologies.
    • Candidate must have the ability to sit/stand for long periods of time, can lift 15 pounds, and is qualified to handle Biosafety Level 2 biological samples such as blood, tissue, bacteria, viruses, and other potentially infectious material.

Desired Traits

    • You want to make an impact on humankind
    • You prioritize “We” over “I”
    • You enjoy getting things done - with super high quality
    • You collaborate effectively with people of diverse backgrounds and cultures
    • You have superior skills and experience, and constantly strive to be world-class in what you do
    • You constantly challenge your own assumptions, pushing for continuous improvement
    • You have a growth mindset
    • You are candid, authentic, and transparent
    • You aren’t afraid of new technologies and relish the opportunity to ‘always be learning’

Siren Fast Facts

    • Located in San Francisco, CA in Mission Bay, a beautiful, waterfront area of San Francisco next to both UCSF and the Gladstone Institutes.
    • University of California San Francisco (UCSF) spin-out from the Paulk lab
    • Strong VC backing from premier investors including: Founders Fund, Lux Capital, Innovation Endeavors, Civilization Ventures
    • CIRM TRAN1 Grant Winner: Translational research grant for the advancement of novel drug products to the clinic
    • Catalyst Program Award Winner: UCSF's translational accelerator focused on advancing UCSF discoveries with clinical impact and commercial potential
    • 1st Place Award - UCSF Innovation Ventures: Awarded by UCSF's Entrepreneurship Center, a premier life science resource for faculty spinouts

Physical Demands Of The Work Environment

    • The position is expected to work onsite full time (8h/d, 40h/wk) during Siren’s normal business hours as well as additional hours as required by the nature of your work assignments. This role is not eligible for remote or hybrid work schedules.
    • Position requires the ability to sit/stand for long periods of time
    • Comfortable handling Biosafety Level 2 (BSL-2) biological samples such as blood, tissue, bacteria, viruses, and other potentially infectious material
    • Ability to lift 15 pounds

Compensation and Benefits

    • Competitive salary, commensurate with experience
    • Stock compensation plan – you’ll be a Siren co-owner
    • Platinum health, dental, and vision benefits
    • High-performance culture
    • Great colleagues
$100,000 - $135,000 a year
In addition to a competitive salary, you will also receive enough equity to feel truly invested in our vision at Siren. The exact salary will be commensurate to experience and will be determined on an individual candidate basis. A competitive benefits package will be provided.
We are an equal-opportunity employer and do not discriminate against any employee or applicant for employment on the basis of race, color, religion, sex, gender identity, sexual orientation, national origin, age, disability, genetic information, or any other characteristic protected by applicable federal, state, or local laws.

Siren may change your position, duties, schedule, and work location from time to time at its discretion.