Staff / Senior Scientist, Assay Development (Chemistry)

What we are looking for in you

We are seeking a Senior or Staff Scientist to join our Assay Development team at a critical stage in platform development. Reporting to the Director of Assay Development, you will be a hands-on expert working at the chemistry-assay interface — developing the chemical methods that enable reliable, high-efficiency sample loading into our expansion assay, and building the novel conjugation, cleavage, and stabilization workflows that power our single-molecule proteome sequencing platform. You will work closely with the Chemistry team to develop sample input methods for new protein and peptide types, including side-chain protection strategies, encoder loading routes, and peptide-from-protein handoff approaches.

What you’ll do

• Expansion assay chemistry & sample loading
• Optimize bioconjugation methods for peptide loading into the expansion assay; establish robust, high-efficiency loading protocols that perform reliably across diverse peptide populations and physicochemical characteristics.
• Identify, characterize, and optimize peptide labeling during the ProSE sequencing assay, leveraging mechanistic understanding of Edman chemistry and amino acid side-chain reactivity and stability.
• Develop reagents and methods to maximize the stability of peptides, DNA, and peptide-DNA chimeras throughout the ProSE sequencing assay.
• Partner with the Chemistry team to develop amino acid side-chain protection chemistries.
• Evaluate compatibility of new chemistries with existing assay components, reagents, and multi-cycle sequencing conditions.
• Evaluate emerging chemistries from the literature and internal pipeline; synthesize and test candidate reagents.
• Novel assay chemistry workflows
• Design and determine the order of operations for chemical manipulations within the assay workflow — including decisions on when specific steps occur on-bead versus off-bead, and how side-chain protection and deprotection strategies are sequenced relative to assay cycles — to ensure compatibility, efficiency, and analytical interpretability.
• Optimize selective cleavage chemistry workflows for use within the sequencing assay.
• Optimize for efficiency, selectivity, and compatibility with assay conditions.
• Develop stabilization strategies for sensitive assay intermediates and conjugates.
• Employ analytical methods — HPLC (RP and IEX), LC-MS/MS, UV-Vis, CE — to characterize conjugation efficiency, adduct identity, purity, and stability of assay intermediates and conjugates.
• Characterize and troubleshoot the impact of the chemical steps of multi-cycle workflows.

What you need

• Advanced degree in organic chemistry, chemical biology, biochemistry, or a related field
• Industry experience designing multi-step chemical workflows in complex biological systems, including sequencing or determining the order of chemical manipulations across assay conditions.
• MS/PhD with 6+/4+ years of experience (for Senior Scientist)
• MS/PhD with 8+/6+ years of experience (for Staff Scientist)
• Demonstrated experience developing site-selective bioconjugation chemistry for native peptides — including N-terminal, C-terminal, and side-chain modification strategies — using click chemistry (CuAAC, SPAAC, IEDDA), NHS-ester coupling, and related bioorthogonal approaches in multi-component peptide systems.
• Experience developing multi-step workflows using peptides, oligonucleotides and bioconjugation techniques including in solution and on surfaces.
• Proficiency with analytical characterization of complex conjugates and assay intermediates: HPLC (RP and IEX), LC-MS/MS, UV-Vis; demonstrated ability to develop and validate analytical methods for novel chemical entities.
• Method-development mindset: history of building and adapting new chemical approaches rather than executing established protocols.
• Ability to function as both an independent contributor and a collaborative partner in a cross-functional team environment.
• Excellent problem-solving skills and attention to detail.
• Excellent written and verbal communication skills, with the ability to work seamlessly with colleagues from diverse scientific and technical backgrounds.
• Ability to thrive in a fast-paced environment with evolving priorities.

Compensation

Estimated Base Salary $123,000 - $187,575

This is the pay range for this position that we reasonably expect to pay. Individual compensation is based on various factors including, experience, education, skillset, and geographic location. This range is for the SF Bay Area, California location and may be adjusted to the labor market in other geographic areas.