Airtree is advertising this role on behalf of one of our portfolio companies, who are currently in stealth mode. We exist to drastically increase access to advanced medicines. We're hiring a senior industry scientist to deliver antibody programs for customers, with particular depth in CHO cell-line development and upstream process development.

Why this role exists Customers come to us with an biologic and a delivery goal. This role turns that starting point into a productive, stable cell line and a robust upstream process that can move confidently toward the factory. You will own the scientific delivery of multiple customer programs: define the development plan, design the decisive experiments, interpret the biology and communicate what the data means.

This is a senior individual-contributor role with real accountability for outcomes, not a broad people-management role and not a role that ends at producing interesting data.

The Role

Owning the scientific delivery of customer antibody programs from cell-line strategy through media and feed development, bioreactor confirmation and a clear scale-up package

Designing and driving CHO cell-line development: host and vector choices, transfection, pool generation, clone selection, screening, stability assessment and cell-banking strategy

Developing and optimising basal media and feeds using disciplined, decision-oriented experiments grounded in cell metabolism and process biology

Translating customer goals, target product profiles and timelines into development plans with clear milestones, risks, decision gates and data packages

Designing DoEs and run plans across high-throughput screens, 300 mL bioreactors and 3 L confirmation runs; setting parameters, sampling plans and analytical requirements

Diagnosing the causes of weak growth, viability, productivity or product quality - separating cell-line, media,



feed and process effects and choosing the next experiment quickly

Working closely with analytics and downstream teams so upstream decisions reflect titre, product quality, impurity burden and the needs of the complete manufacturing process

Communicating directly and credibly with customers: explaining results, trade-offs, uncertainty and the recommended path forward in clear scientific and commercial language

Delegating routine execution to operations technicians while staying close enough to the work to protect scientific quality and stepping in hands-on when the biology demands it

Turning lessons from individual programs into reusable platform rules, operating windows and better development workflows Requirements Essential

At least five years of relevant industry experience is required in addition to the PhD. You have delivered mammalian cell-culture or antibody-development programs in a biotechnology or biopharmaceutical setting; academic experience alone is not sufficient A track record of personally taking antibody-producing CHO cell lines from transfection or pool generation through clone selection, stability assessment, productivity optimisation and banking

Substantial experience developing or optimising cell culture processes A record of designing rigorous experiments and making sound decisions from incomplete data across multiple concurrent development programs

Experience owning program outcomes and communicating directly with internal or external customers, not only completing an assigned scientific work package





Strong written and verbal communication. You can give the direct answer, defend it from the data and explain the implications to scientists and non-specialists

High pace, high ownership and low ego. You are comfortable being accountable for delivery in a small team and remaining hands-on when needed Nice to have A PhD in cell biology, molecular biology, biochemistry, biotechnology, bioprocess engineering or a closely related field

Experience developing monoclonal-antibody cell lines from sequence or vector design through research cell bank or master-cell-bank readiness

High-throughput cell-line or media screening, automation, ambr-class systems or other parallel bioreactor platforms

Biologics analytics literacy, including titre, metabolites, glycosylation, charge variants, aggregation, HCP and DNA

Scale-up, technology transfer, CMC, GMP or regulatory-development experience

Experience writing customer-facing development reports, technical packages or regulatory-supporting documentation What success looks like In your first 3-6 months, success looks like becoming the trusted scientific owner of customer program. Each program has a clear development logic, decisive experiments and an honest view of risk; customers understand what the data says and what happens next; and strong biology moves efficiently from high-throughput screening into repeatable bioreactor performance. Routine execution runs through the operations team, while you stay accountable for scientific quality and delivery.

How we work Small team, rapid cycles, flat. Our seed round is closed, so we're building now. We're in Alexandria, Sydney, and you'll need the right to work in Australia. You will work shoulder to shoulder with upstream operations, analytics and downstream scientists, with direct access to customers and meaningful responsibility from day one.

📌 Senior Scientist - Antibody Bioprocess Development (Sydney)
🏢 AirTree
📍 Sydney