Job Description

About the Company

Institutionally backed biotech focused on neuroscience and the development of novel therapeutics.

Position Overview

We are seeking a Senior Scientist to help build and advance our peptide- and protein-based delivery

platform. This is a hands-on platform development position with technical responsibilities across

molecular design, recombinant shuttle production, bioconjugation, and biophysical, biochemical, in

vitro, and in vivo characterization. The scientist will develop new capabilities, solve technical

problems, and generate data that guides platform and program decisions.

The ideal candidate is a creative, scientifically curious thinker who questions assumptions, proposes

new approaches, and adapts methods to unfamiliar problems. They enjoy working across disciplines

and will contribute wherever technical support is needed as the platform evolves. Responsibilities

extend beyond biochemistry and assay development.

Key Responsibilities

Platform Development and Technical Problem Solving

• Identify technical gaps and develop experimental approaches, workflows, and tools that improve

the platform across discovery, molecule production, characterization, and delivery.

• Design hypothesis-driven experiments, test alternative approaches, and recommend practical

next steps when results challenge current assumptions.

Recombinant Shuttle Production

• Design expression constructs and produce, purify, and characterize recombinant shuttles,

including VHHs, Fc fusion proteins, and recombinant peptide constructs, using appropriate

microbial and/or mammalian expression systems.

• Optimize expression, folding, recovery, and purification workflows; assess protein quality, purity,

aggregation, and stability using appropriate analytical methods.

Small Scale Bioconjugation

• Perform and optimize small-scale conjugation of peptide or protein shuttles to oligonucleotides

or other payloads, including reaction setup, purification, and recovery.

• Characterize conjugates for purity, conjugation stoichiometry, residual free components, and

retained binding and activity, using in-house methods and external analytical support as

needed.

3210 Merryfield

San Diego, CA 9212

Diaxis Therapeutics,

Assay Development and Execution

• Develop, optimize, and run biochemical and biophysical assays to evaluate shuttle and

conjugate binding, affinity, kinetics, selectivity, competition, and activity, using methods such as

BLI, SPR, and plate-based assays.

• Develop flow cytometry assays to quantify cell-surface binding and internalization of shuttles

and conjugates, with controls and methods that distinguish surface-bound material from

internalized material.

• Develop cell-based functional assays to assess payload activity, including oligonucleotidemediated gene knockdown, and relate functional results to binding and internalization data.

• Establish assay conditions, controls, and performance criteria for screening, hit confirmation,

and lead optimization.

• Troubleshoot assay variability, interference, and other technical challenges.

• Document methods and results clearly so assays can be reproduced and used across

programs.

In Vivo Studies and Translation

• Provide technical support for the design, execution, and interpretation of in vivo studies with

biology colleagues and external partners, including pharmacokinetics, biodistribution, tissue

delivery, and functional activity.

• Support bioanalytical methods for shuttles and payloads in biological samples, and integrate in

vivo findings with biochemical, biophysical, and cell-based data to guide optimization.

Screening and Hit Validation

• Support peptide and protein screening campaigns and follow-up testing of selected hits,

including hits from display-based discovery programs.

• Confirm promising hits using orthogonal assays and appropriate counter-screens.

• Generate concentration-response, binding, competition, and selectivity data to support shuttle

and conjugate optimization.

• Work with peptide chemistry and protein engineering colleagues to evaluate how sequence

changes, linkers, and conjugation affect molecular performance.

Collaboration and Data Interpretation

• Analyze results, identify limitations, and recommend follow-up experiments.

• Partner with peptide chemistry, protein engineering, biology, and platform colleagues to ensure

experiments address key program questions.

• Coordinate with external partners on specialized conjugation and analytical characterization

needs.

• Present findings and recommendations in project meetings.

• Help improve shared assay workflows and mentor less experienced team members as

appropriate.

3210 Merryfield

San Diego, CA 9212

Diaxis Therapeutics,

Qualifications

Required Qualifications

• PhD in Biochemistry, Chemical Biology, Protein Engineering, Biology, or a related field with 3 or

more years of relevant industry experience; or a master’s degree with equivalent experience.

• Demonstrated hands-on experience in recombinant protein expression, purification, and

characterization.

• Practical experience performing and troubleshooting small-scale protein or peptide

bioconjugation.

• Strong hands-on experience independently developing and troubleshooting biochemical,

biophysical, and cell-based assays.

• Hands-on experience with mammalian cell culture and flow cytometry assay development for

cell binding and internalization, including appropriate controls, gating, and data analysis.

• Experience contributing to in vivo study design, bioanalysis, or interpretation of pharmacokinetic

and biodistribution data.

• Experience supporting screening, hit validation, or lead optimization in a drug discovery setting.

• Experience with binding and characterization methods such as BLI or SPR, plate-based assays,

and protein analytical techniques.

• Ability to design appropriate controls, assess data quality, and recognize potential assay

artifacts.

• Strong experimental, analytical, documentation, and communication skills.

• Independent problem solving, sound experimental judgment, and willingness to learn new

methods and contribute across the platform as priorities evolve.

Preferred Qualifications

• Experience with phage display and/or yeast display library design, construction, and screening,

including selection strategy and hit validation.

• Experience analyzing enrichment and next-generation sequencing data from display screens.

• Experience with cyclic peptides, oligonucleotide conjugates, or receptor-mediated delivery.

Stealth-stage biotech

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