# Best Harvest Moment for Colon Cancer Cells From 2D Cultures for 3D Tumoroid Bioprinting: An Experimental Observational Study

## TL;DR

This study identifies the optimal time to harvest colon cancer cells for 3D tumoroid bioprinting based on cell survival and quality in 2D cultures.

## Contribution

The study experimentally determines the best harvesting day for bioprinting-ready colon cancer cells from 2D cultures.

## Key findings

- Patient-derived colon cancer cells showed variable survival in 2D cultures.
- Cells from Patients 5 and 6 maintained the required density and morphology for bioprinting.
- Day 9 was identified as the optimal harvesting time for bioink formulation.

## Abstract

Three-dimensional tumoroids promise to enhance personalized oncology by recapitulating many features of the tumor microenvironment. In this study, human colon cells from biopsy specimens were expanded in 2D cultures and subsequently analyzed for viability, morphology, and cell counts using phase-contrast microscopy combined with FIJI ImageJ processing. Notably, survival among patient-derived cultures was variable: Patients 1 and 2 cells did not survive past Day 1; Patient 3 cells survived for nine days; Patient 4 cells, for four days; Patient 5 cells survived for 28 days - with cells seeded to a second flask (designated 5S1) on Day 9 that survived for 20 days - and Patient 6 cells survived for 17 days. Our observations indicate that only cultures with extended survival (notably Patients 5 and 6) maintain the density and morphological uniformity required for optimal bioink formulation and subsequent bioprinting of tumoroids. According to the data obtained, the best day for harvesting cells for mixing with bioink for bioprinting is the ninth day.