Nandhu S KumarAI & MACHINE LEARNING
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Tox-NIO

Optimizing molecular features with projected gradient descent to reduce predicted toxicity.

DISCIPLINE

Machine Learning

TIMELINE

Sep to Dec 2025

BUILT WITH

Neural optimization, ZINC-250k, Gradient descent

System architectureFIG. 05
PROJECTED GRADIENT DESCENTMOLECULAR FEATURE OPTIMIZATION0.550.28STARTING SCOREOPTIMIZED SCOREPREDICTED TOXICITY IN PROJECT TESTS
  1. Molecule

    Molecular candidates are represented through features from the ZINC-250k dataset.

  2. Prediction

    A model scores the candidate’s predicted toxicity.

  3. Optimization

    Projected gradient descent updates molecular features to reduce the prediction.

  4. Evaluation

    The resulting predicted toxicity is compared with the starting score.

Machine LearningConceptual overview
INSIDE THE SYSTEM / SELECT A STAGE

Molecular candidates are represented through features from the ZINC-250k dataset.

Problem

Searching for molecular candidates with lower predicted toxicity can be computationally expensive. Tox-NIO explores direct optimization of molecular features as an alternative to random search.

Implementation

I developed a molecular editor based on Neural Input Optimization. It uses projected gradient descent to optimize molecular features on the ZINC-250k dataset, with the aim of reducing a model’s predicted toxicity score.

Technical decisions

  • Used Neural Input Optimization to modify molecular features.
  • Applied projected gradient descent in place of a genetic search approach.
  • Evaluated changes using predicted toxicity on ZINC-250k compounds.

Results

In my project evaluation, predicted toxicity fell from about 0.55 to 0.28, a reduction of roughly 50%. These scores come from the toxicity model used during optimization.

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