Principal Scientist, LNP Platform & Process Development

About Tr1X Tr1X is a clinical-stage biotechnology company developing engineered Tr1 cell therapies to restore immune balance in autoimmune and inflammatory diseases. Leveraging the unique biology of Tr1 cells, the company is advancing a pipeline of off-the-shelf allogeneic and in vivo CAR-Tr1 therapies designed to deliver targeted immunoregulation and address diseases driven by immune dysfunction, including transplant-related complications. Founded by pioneers in the discovery of Tr1 cells, Tr1X, Inc. is focused on developing durable, potentially curative therapies for conditions with high unmet need. For more information, visit www.tr1x.bio. Position Summary The Principal Scientist, LNP Platform & Process Development (Scientist) is an experienced hands-on, lab-based, individual contributor that leads the design, development, and optimization of lipid nanoparticle (LNP) formulation and process development efforts supporting the Tr1X in vivo CAR-Treg platform. This individual plays a central role in developing and advancing the targeted lipid nanoparticle (tLNP) delivery systems from early research optimization through scalable, IND-enabling development. This is a high-impact, foundational role within the company. The Scientist helps design and implement the LNP backbone of the platform and influence both short-term program execution and long-term manufacturability strategy. The Scientist brings deep hands-on expertise in LNP formulation and process development, strong analytical rigor, and the ability to thrive in a fast-paced startup environment. Key Responsibilities Lead the design, development, and optimization of LNP formulations for mRNA delivery, including targeted LNP systems incorporating conjugated or functionalized lipids.Evaluate lipid composition, formulation parameters, and mixing conditions to optimize particle size, polydispersity, encapsulation efficiency, surface functionalization, stability, release characteristics, and biological performanceDevelop and optimize research-scale, compatible production processes for consistently making high-quality tLNPs in-house at milligram quantitiesLead the development and optimization of accompanying analytical characterization methods (both in-house and at the external CDMO), including but not limited to DLS, fluorescence-based assays such as Ribogreen, HPLC/UPLC methods (CAD, UV, IP-RP, SEC, IEX), LC-MS, and endotoxin testing.Interpret analytical and stability data to establish meaningful correlations between physicochemical properties and biological function.Collaborate closely with platform biology teams to support in vitro and in vivo studies, prepare development reports and technical documentation, and contribute to technology transfer activities with external CDMO partners.Spearhead IND-enabling documentation and contribute to defining the long-term strategy for scalable LNP platform development.Participate in cross functional development and manufacturing projects to ensure company objectives are met and exceeded.Perform other responsibilities as required based on business needs. Required Qualifications & Experience Ph.D. in Chemical Engineering, Bioengineering, Pharmaceutical Sciences, Chemistry, or a related field with a minimum 6 years of relevant industry experience; or M.S. with 10+ years; or B.S. with 12+ years.Demonstrated in-depth expertise in LNP formulation and process development, including hands-on experience with microfluidic or scalable mixing technologies and downstream purification strategies such as TFF.Strong experience with analytical characterization of tLNP systems and application of statistical design tools for process optimization.Highly organized, scientifically rigorous, and capable of independently driving projects while collaborating effectively in a multidisciplinary startup environment.Experience with mRNA therapeutics or nucleic acid delivery systems.Experience with conjugation of targeting ligands – antibodies, nanobodies, peptides - to lipid nanoparticles is required.Prior exposure to immunotherapy or in-vivo cell therapy platforms preferred.Experience correlating formulation attributes with in vivo performance (mouse, NHP) highly desirable. Ability to actively serve, collaborate, and develop relationships inside and outside the organization.Excellent written and oral communication skills.Strong analytical and problem-solving skills; great attention to detail and the ability to drive timely and fact-based decision making.Ability to function in a rapidly changing environment and handle multiple priorities.Experience with mRNA production and analytical quality control preferred. Other Requirements Legally authorized to work for any employer in the U.S.Position is on site in San DiegoTravel may be required up to 10% of the time The job responsibilities and requirements provided above are intended to describe the general nature of the work performed by individuals assigned to this job classification. It is not intended to be an exhaustive list of all duties and requirements. Tr1X retains the right to add, change, or delete duties, education, experience or any other requirements of the position at any time. Working at Tr1X At Tr1X, our team is united by a singular shared mission: to transform patients' lives through breakthrough science. We are a group of skilled experts driven by urgency, innovation and a collaborative spirit. Our culture thrives on excellence, positivity, persistence and the agility to tackle new challenges head-on. With an unwavering commitment to patients, science and one another, we foster an environment where team members feel engaged, supported and empowered to make a meaningful impact. We envision a world where autoimmune diseases are not just being treated but are cured. Base Pay Hiring Range Anticipated: $169,000 - $185,000 Tr1X considers a variety of factors to determine salary such as education, years of experience, time in the position level, training, knowledge, skills, geographic location, and the market value of the position. Compensation and Benefits Tr1X provides a fair and competitive total rewards program that includes base salary; discretionary annual target bonus; incentive stock options; 401(k) retirement plan with company contribution; health and welfare insurance plans for employees (and their families) that include medical, dental, vision, long-term and short-term disability, and life insurance; paid time off (PTO); and paid holidays. Tr1X embraces a diverse, open, and inclusive environment and believes a strong culture connection is key to success. Tr1X is committed to fairness in recruitment, hiring, transfer, promotion or any other employment practice without regard to race, color, citizenship, national origin, ancestry, religion, sex, pregnancy, marital status, sexual orientation, gender, gender identity and expression, age, physical and medical disability, medical condition, genetic information, political affiliation, protected veteran status, or any other characteristic protected by law. If you are an individual needing assistance to complete an employment application or would like to request an accommodation, please contact the Human Resources department at careers@tr1x.bio. Notice to Employment Agencies The Tr1X talent acquisition program is managed through internal resources, and unsolicited referrals and resumes are not accepted from employment agencies, unless advance written authorization is granted from the human resources department. Tr1X shall not be liable for any fees arising from any unsolicited or unauthorized candidate information received relative to position vacancies.