Senior Assay Development Scientist/Engineer

About SiPhox Health

SiPhox Health is redefining clinical immunoassay diagnostics by miniaturizing the analytical power of a central lab into an accessible, affordable, at-home platform. Our silicon-photonics architecture unites advanced biochemistry, microfluidics, and semiconductor-grade manufacturing to deliver precise, multiplexed biomarker quantification in minutes on a device the size of a coffee maker.

We are building what we believe will become the first mass-market photonic blood analyzer, enabling continuous improvement in chronic disease management through frequent, high-quality testing.

The Opportunity

We are looking for a Senior Assay Development Scientist or Engineer who wants to build assays that have never been built on this kind of platform before. If you thrive on developing rigorous, quantitative immunoassays, including challenging free/competitive assays, and want your work to directly ship in a consumer device used by millions, this is one of the rarest opportunities in diagnostics today.

This role sits at the center of platform innovation, contributing directly to analytical chemistry, surface chemistry, microfluidics, and silicon photonics integration. You will shape a growing assay menu that spans hormones, inflammatory markers, metabolic proteins, and future pediatric/specialty panels.

What You’ll Do

Core Assay Development

• Develop quantitative sandwich and competitive immunoassays (including free hormone assays, displacement-driven formats, and low-abundance biomarkers) on a silicon-photonic resonance platform.
• Design, execute, and interpret experiments focused on:
• Binding kinetics & equilibrium optimization
• Surface functionalization strategies
• Competitive assay dynamic-range shaping
• Calibrator and control development (matrix selection, commutability)
• Assay precision, stability, robustness

Analytical Performance & Validation

• Own assay verification and validation aligned with CLSI standards (EP05, EP06, EP07, EP09, EP10, EP17).
• Establish and demonstrate performance for:
• Analytical sensitivity & functional limit (LoB/LoD/LoQ)
• Linearity & reportable range (including hook effects, competitive assay inflection characterization)
• Repeatability, reproducibility, and nested CV analysis
• Interference and cross-reactivity studies
• Matrix equivalency & recovery studies
• Build calibration models for a novel platform (e.g., 4PL/5PL, competitive curve inversion, chip-specific normalization frameworks).

Cross-Functional Integration

• Collaborate deeply with photonics, microfluidics, reader electronics, manufacturing, and product engineering teams to close the loop on real-world assay performance.
• Work with process development and chemistry groups to scale assays from prototype to production, enabling high-volume, chip-based manufacturing.

Documentation & Execution

• Deliver high-clarity technical reports, protocols, V&V documentation, and design-history file content that meets IVD and FDA expectations.
• Present results across the company to inform design decisions and product milestones.

What We’re Looking For

Technical Background

• PhD 2 years, or MS 6 years in biochemistry, chemical engineering, analytical chemistry, biophysics, bioengineering, or related fields.
• Expertise in immunoassay development (sandwich and competitive). Experience with free hormone assays is a major plus.
• Demonstrated ability to independently solve complex analytical and biochemical problems.
• Hands-on experience with complex analytical workflows, assay automation, and instrumentation.
• Strong understanding of calibration design, commutability, and control strategies.
• Familiarity with statistical analysis of assay performance, including mixed-model ANOVA, CV decomposition, and method-comparison frameworks.

Regulatory & Platform Experience (Bonus)

• Experience with IVD development, ISO 13485, or 21 CFR 820.
• Experience with POC or novel-platform assay development.
• Knowledge of label-free sensors, waveguides, or photonic resonance systems.
• Experience with Python, R, or MATLAB for data analysis, curve fitting, and automation.

Personal Traits

• Strong scientific intuition paired with rigorous data discipline.
• Thrives in a fast-paced, milestone-driven startup environment.
• Creative problem solver willing to challenge established assay paradigms.
• High integrity, willingness to own outcomes, and a collaborative mindset.

Why This Role Is Unique

Most assay developers spend their careers optimizing assays on platforms that already exist.

At SiPhox, you will:

• Build the first generation of photonic immunoassays deployed in consumer health.
• Design assays whose constraints are shaped by semiconductor physics as much as biochemistry.
• Work on hard problems (free hormone assays, multiplexing, competitive equilibrium, small-volume matrices) where innovation, not incrementalism, wins.
• See your work ship in a product used at home by real people, not just research labs.

If you want to work at the frontier of diagnostics (where photonics, biochemistry, and consumer health converge) we’d love to meet you.