Scientist I/II, Modality Engineering

Lexeo TherapeuticsNew York City, New YorkOn-siteFull-timeNew grad, 0–1 yearsListed 2 hours ago

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About this role

Primary Responsibilities

- Select and manage CROs for oligonucleotide synthesis and bioconjugation, including scope, vendor guidance, data review, quality, and delivery timelines

- Design and oversee oligonucleotide conjugates using peptides, antibodies, or ligands; optimize conjugation chemistry, linkers, purification, and analytical characterization

- Build or outsource methods to confirm identity and assess purity using HPLC, LC-MS, SDS-PAGE, spectroscopy, and other fit-for-purpose assays

- Engineer AAV capsids, regulatory elements, and transgene cassettes; conduct cloning, plasmid preparation, sequencing, and research-grade vector production

- Design and screen sequence or vector/capsid with NGS readouts, applying state-of-the-art analytical methods to improve potency, selectivity, and production yield

- Partner with In Vitro Pharmacology, In Vivo Physiology, Analytical DMPK, and CMC to define screening cascades, interpret data, assess developability and manufacturability, select leads, and support go/no-go decisions

- Support molecule advancement through process development and formulation while identifying technical risks and recommending practical experiments or external capabilities

- Write SOPs, maintain and troubleshoot instruments, document work in the ELN for intellectual property and regulatory filings, present results, and monitor platform advances

Required Skills and Qualifications

- PhD in chemistry, chemical biology, biochemistry, molecular biology, or a related field with 0–3 years of postdoctoral or industry experience; or MS with 5+ years of industry experience

- Hands-on experience synthesizing, purifying, and characterizing research-scale ASOs, siRNAs, or bioconjugates using automated solid-phase synthesis, chromatography, and mass spectrometry

- Working knowledge of ASO/siRNA therapeutic chemistry, backbone and sugar modifications, class-related toxicity, various delivery approaches

- Strong research productivity demonstrated through publications, patent filings, or comparable technical contributions

- Clear written and verbal communication skills, sound scientific judgment, and the ability to manage multiple projects in a collaborative, fast-paced team

- Ability to regularly work onsite at our HQ in New York City

Preferred Skills and Qualifications

- Industry experience in a small, fast-paced biotech is highly preferred

- Working knowledge of AAV biology and vector design

- Hands-on experience in AAV capsid engineering, pooled library design, and NGS data analysis

- Antibody- or peptide-oligonucleotide conjugate (AOC/POC) design or linker discovery

Compensation is dependent on qualifications and experience