PhD Cell Biologist · AI/ML Scientist

Saman
Hussain

A cell biologist working at the intersection of advanced microscopy and AI.

Explore research →
Description of image

01About Me

Neuroscience, microscopy & the frontier of AI

I am a cell biologist with expertise in live fluorescence imaging, hair cell biology, and the application of machine learning to biological problems. My research has centered on how sensory hair cells in the inner ear and lateral line detect, encode, and transmit signals to the brain.

I completed my PhD in Biology at Harvard University, then worked as a neuroscientist at the National Institutes of Health (NIH/NIDCD), where I published on ribbon synapse development and spontaneous calcium signaling in stereocilia.

I currently work as an independent contractor with Mercor Intelligence, designing and evaluating expert-level scientific problems used to train frontier AI models (Google Gemini, Claude and ChatGPT) on PhD-level reasoning in the life sciences.

Current
Independent Contractor Mercor Intelligence
LLM training on PhD-level science
Previous
Neuroscientist NIH — National Institute on Deafness and Other Communication Disorders
Kindt Lab & Kachar Lab
Education
PhD, Molecular and Cellular Biology Harvard University — Garner Lab
Focus
Sensory Neuroscience & AI Hair cell biology · Live imaging · ML for biology · LLM evaluation

02Research & Projects

I

Ribbon synapse formation in zebrafish hair cells

Using high-resolution live cell microscopy in zebrafish, we found that small ribbon precursors spread throughout developing hair cells, then move along microtubule networks to the presynaptic active zone, fusing into mature ribbons. Disrupting microtubules prevents normal synapse formation, with implications for age-related and noise-induced hearing loss.

II

Spontaneous calcium transients in hair cell stereocilia

Using genetically encoded Ca²⁺ sensors and advanced microscopy, we detected spontaneous Ca²⁺ transients in stereocilia in the absence of movement. This activity is abolished by MET channel blockers and is conserved across mouse and zebrafish. This work revealed new insights into channel assembly, maturation, and function.

III

How bacterial cells form rod shapes

The MreB protein, an actin homolog in Bacillus subtilis, acts as a curvature sensor that aligns with regions of greatest membrane curvature to guide cell wall synthesis. Even in spherical mutants, local curvature fluctuations create bulges that MreB exploits to regenerate rod shape. This work determined the mechanism behind rod shape formation and identified new potential antibiotic targets.

IV

Studying actin-myosin interactions in vitro

Using a gliding assay with immobilized myosin II and purified actin, we found that filament collisions progressively reduce inter-filament angles, driving emergent collective alignment. High actin and myosin concentrations promote ordered motion, but only up to a threshold, beyond which excess myosin causes disorder.

AI & Computational Projects

AI/ML, and computational biology projects focused on image analysis, tracking, and interactive visualization.

3D Zebrafish Hair Cell Segmentation

Built a deep-learning-based pipeline to segment individual hair cells in 3D. This approach combines Cellpose with custom tracking to visualize development and synapse formation over time, enabling quantitative analysis of cellular dynamics.

Image 1 Image 2

Calcium transient detection in individual stereocilia

Developed a Python-based pipeline for automated detection of spontaneous calcium transients in GCaMP timelapse imaging of inner ear and vestibular hair cell stereocilia in mouse tissue explants.

2D–3D Protein Tracking in Hair Cells

Developed MATLAB pipelines for tracking protein motion in 2D and 3D in zebrafish hair cells, combining high-resolution imaging with quantitative motion analysis.

Bacterial Cell Shape Analysis

Built a segmentation and contour-analysis pipeline to study bacterial morphology to help link shape differences to genetic perturbations.

Bacterial segmentation

MreB Filament Tracking

Applied particle tracking to classify MreB filament motion using mean-squared displacement analysis to distinguish directional vs diffusive behavior.

Actin Alignment via Ellipse Fitting

Developed an image-analysis method to quantify actin filament orientation using ellipse fitting in time-lapse microscopy. This enables comparison of cytoskeletal organization across conditions.

Actin alignment

Gesture-Controlled PyMOL

Integrated Leap Motion with PyMOL to control molecular structures using hand gestures. Enables intuitive rotation, zooming, and interaction—ideal for research demos and teaching.

03Publications

2025

Microtubule networks in zebrafish hair cells facilitate presynapse transport and fusion during development

Hussain, S., Pinter, K., Uhl, M., Wong, H-T., Kindt, K.S.

eLife Open Access
View paper →
2025

Spontaneous calcium transients in hair cell stereocilia

Hussain, S.*, Sedlacek, M.*, Cui, R., Zhang-Hooks, W., Bergles, D., Kachar, B.  *co-first authors

Scientific Reports · Nature Portfolio Open Access
View paper →
2022

In vivo analysis of hair cell sensory organs in zebrafish: from morphology to function

Hussain, S., Aponte-Rivera, R., Barghout, R.M., Trapani, J.G., Kindt, K.S.

Neuromethods, vol. 176 · Springer Nature
View chapter →

Full list on Google Scholar →

04Curriculum Vitae

Experience

Independent AI Contractor

2025 – Present
Mercor Intelligence

Training and evaluating frontier large language models on PhD-level scientific reasoning.

Neuroscientist

2019 – 2025
NIH/NIDCD (Kindt Lab & Kachar Lab)

Sensory hair cell research using advanced fluorescence microscopy and live cell imaging in zebrafish and mouse models.

PhD Researcher

2012 – 2018
Harvard University — Garner Lab

Doctoral research in cell biology - Using quantitative live fluorescence imaging to understand how bacteria form rod shapes.

Education & Skills

PhD, Biology

2018
Harvard University

Experimental Skills

Live Imaging · Confocal microscopy · Light-sheet microscopy · TIRFM · Calcium imaging (GCaMP) · Zebrafish and mouse genetics · CRISPR · Molecular Biology

Computational & AI Skills

Python · · FIJI/ImageJ · R · MATLAB · LLM evaluation & RLHF · 2D/3D particle tracking & 2D/3D cell segmentation

Download full CV (PDF) ↓

05Contact

Let's work
together

Open to collaborations in sensory neuroscience, AI and biology, and LLM evaluation. Feel free to reach out.