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41 changes: 40 additions & 1 deletion 0_domain_study/README.md
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# Domain Research
# README

Throughout my research with microscopy images of gastrointestinal
tissues, I have recognized an important methodological limitation:
the lack of a reproducible and scalable method to measure the
localization of nanoparticles inside cells. In experiments on
nanoparticle exposure, it is common for investigators to use manual
segmentation of cells, followed by visual inspection to determine
the localization of nanoparticles inside or outside the boundaries
of cells. This approach may be acceptable for a limited number of
experiments, but it is soon recognized as inadequate when the scale
of experiments is increased.

This manual approach is, by its very nature, time-consuming and
requires considerable human effort, especially when working with
high-resolution microscopy images. More importantly, it also injects
an element of subjectivity into the research workflow, where the
determination of the boundaries of cells and the localization of
nanoparticles may vary between different investigators. This is
especially true even within the same research group, where different
investigators may have different interpretations, resulting in
inconsistencies in results. This inter-observer variability is an
important limitation, especially when the number of experiments is
increased to hundreds or even thousands of images.

In fact, nanoparticle exposure studies in modern times commonly
result in the production of large volumes of imaging data that are
complex in nature. However, the analytical process that follows the
experiment has not always kept pace with the developments made in
experimentation, creating a gap between biological experimentation
and quantitative reproducibility.

It was out of this gap that the present project was formulated. In
essence, the problem that was identified was the requirement of a
computational framework that would be objective, reproducible, and
efficient enough to quantify nanoparticle accumulation in
gastrointestinal tissue. In other words, the question that was asked
was: how can nanoparticle localization in cells be measured
efficiently, ensuring reproducibility, transparency, and biological
accuracy?
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# Actionable Research Question

In the context of the stated constraints, the underlying biological
problem was reformulated into a computationally tractable
research question.

---

## Main Research Question

Can a machine learning-based segmentation pipeline be developed
to reproducibly quantify the localization of particles in
gastrointestinal tissue cells?

---

## Specific Research Questions

1. Can the Cellpose model be trained to reproducibly segment
adipocytes from colon tissue images?

2. Can particle localization be classified as inside or outside
segmented cells?

3. Can image-level quantitative metrics be extracted
reproducibly?

---

## Stated Constraints

- Limited availability of annotated image masks
- Lack of a ground-truth nanoparticle image set
- Project time constraints
- Requirement to ensure reproducibility
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# Background Review

## 1.Industrial Production, Nanoscale Transition, Emerging Biological Question

In the last ten years, the use and consumption of nanomaterials
have seen an increase. This is particularly true in the fields of
biotechnology, pharmacology, food technology, and medical
industries. Among the engineered nanomaterials, titanium dioxide
(TiO₂) is one of the most synthesized nanomaterials. It is
responsible for about 70% of the total pigment production worldwide
and is produced at the rate of 10 million tons annually. A
significant fraction of the total production is at the nanoscale.

Nanoparticles with diameters smaller than 100 nanometers,
particularly those in the 5-50 nanometer range, have fundamentally
different physicochemical properties. This is particularly true
because the surface area to volume ratio is dramatically increased.
This increase is responsible for the enhanced reactivity of the
nanomaterial. The transition from bulk material to nanoscale is
responsible for the new biological questions. The exposure of the
nanomaterials for an extended time, particularly through ingestion,
can lead to the development of new interactions between the
epithelial tissue and the nanoparticles. The transition from bulk
material to nanoscale is responsible for the new biological
questions. The exposure of the nanomaterials for an extended time,
particularly through ingestion, can lead to the development of new
interactions between the epithelial tissue and the nanoparticles.
The transition from bulk material to nanoscale is responsible for
the new biological questions. The exposure of the nanomaterials for
an extended time, particularly through ingestion, can lead to the
development of new interactions between the epithelial tissue and
the nanoparticles.

The scientific challenge is no longer the characterization of the
material but the spatially localized biological location. Where are
the nanoparticles? Are they outside the cells, or are they inside
the cells? Can the location of the nanoparticles be quantitatively
determined?

---

## 2. Biological Effects and Tissue Level Complexity

Titanium dioxide and other metal oxide nanocomponents have
traditionally been considered biologically inert in bulk form.
However, the biological effects of nanoscale titanium dioxide
particles have been found to differ. Experimental studies have
shown that these nanoparticles are capable of crossing epithelial
membranes, penetrating the tissue structures of the
gastrointestinal tract, and directly interacting with intracellular
structures. This can lead to the disruption of cellular signaling
pathways and an increase in oxidative stress, which is the product
of the reaction of reactive oxygen species. Oxidative stress is an
important component in the pathogenesis of connective tissue and
gastrointestinal diseases. It can lead to inflammation, tissue
remodeling, genotoxicity, and apoptosis. This is particularly true
in tissues with high rates of turnover and remodeling.

The gastrointestinal tract is the primary target for ingested
nanoparticles. This area is particularly vulnerable to the
cumulative effects of exposure. The epithelial and sub-epithelial
structures are particularly vulnerable in the context of systemic
and connective tissue diseases, as has been shown by clinical and
experimental studies.

Despite the accumulation of biological data on the effects of
nanoparticles, an important gap remains. The conclusions are based
on the qualitative analysis of microscopic structures.
Quantitative spatial analysis of the localization of nanoparticles
at the cellular level is not well developed. To bridge the gap, not
only biological expertise is necessary, but also the application of
computational techniques capable of converting visual data into
quantifiable results.

---

## 3. Deep Learning-Based Segmentation and New Models

Histological imaging is an important instrument for studying
tissue-level effects. Microscopy helps to visualize the shape of
the cells and the distribution of nanoparticles. Manual
segmentation is subjective and not very efficient.

Rule-based segmentation models face challenges related to the
complexity of histological images due to heterogeneity in staining
and cell morphology.

Machine learning models for segmentation are an important
breakthrough in methodology. Machine learning models learn spatial
representations of cell shape and texture.

CellPose[5] is a generalist deep learning model for segmentation of
cell images that has shown good cross-domain performance. It uses
vector flow representations to segment cell images.

Recently, CellPose-SAM has been developed by combining the
generalist segmentation performance of CellPose with the
promptable segmentation architecture of the Segment Anything Model
(SAM) [6]. This new model has shown better generalization and
flexibility to unseen data, allowing for superhuman performance
across a range of biological data.

The above discussion provides an opportunity to delve deeper into
the learning objectives of deep learning models and train new
models for segmentation while studying the behavior of the models
from a biological perspective.

---

## 4. From Segmentation to Integrated Scientific Software

The scientific problem, therefore, goes beyond the simple detection
of cells. It requires the development of a comprehensive scientific
problem-solving process that incorporates image preprocessing,
deep learning-based segmentation, nanoparticle localization
analysis, and the creation of structured statistical output. Rather
than the segmentation tool standing alone, the goal here is to
integrate the tool within a comprehensive scientific system.

This paradigm aligns perfectly with the project’s learning goals,
which include adapting Cellpose models to colon histology,
exploring the capabilities of Cellpose-SAM, using cutting-edge
deep learning to solve an open biomedical problem, and creating
independent scientific software that unifies segmentation,
simulation, and quantification within a reproducible paradigm.

In this paradigm, deep learning becomes a bridge between the visual
information of microscopy and the structured scientific process.

---

## References

1. Chen P, Zhao J, Zhang H, et al. Tangshen Formula Attenuates
Colonic Structure Remodeling in Type 2 Diabetic Rats.
Evid Based Complement Alternat Med. 2017;4064156.

2. Vona R, Giovannetti A, Gambardella L, et al. Oxidative stress
in the pathogenesis of systemic scleroderma.
J Cell Mol Med. 2018;22:3308–3314.

3. Walecka I. Systemic sclerosis and the gastrointestinal tract.
Gastroenterology Rev. 2017;12(3):163–168.

4. Nica AE, Alexa LM, Ionescu AO, et al. Esophageal disorders in
mixed connective tissue diseases.
J Med Life. 2016;9(2):141–143.

5. Pachitariu M, Rariden M, Stringer C.
Cellpose-SAM: superhuman generalization for cellular
segmentation.
bioRxiv. 2025;651001.
doi:10.1101/2025.04.28.651001.

6. Stringer C, Wang T, Michaelos M, Pachitariu M.
Cellpose: a generalist algorithm for cellular
segmentation.
Nat Methods. 2021;18:100–106.
doi:10.1038/s41592-020-01018-x.
(Originally published as bioRxiv preprint 2020;
doi:10.1101/2020.02.02.931238.)
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