Surface-Engineered Paper Hanging Drop Chip for 3D Spheroid Culture and Analysis

Area of Science:

• Biomaterials Engineering
• Microfluidics
• Cell Culture Technology

Background:

• Cell culture often faces challenges with nonspecific adsorption and biofouling.
• Existing "body-on-a-chip" platforms can be costly and complex.
• Developing low-cost, high-throughput platforms for 3D cell culture is crucial.

Purpose of the Study:

• To create a biofouling-resistant, hydrophobic paper substrate for 3D spheroid culture.
• To demonstrate the utility of this platform for in-situ analysis and drug testing.
• To explore the potential of paper as a material for "body-on-a-chip" systems.

Main Methods:

• Hydrophilic cellulose fibers were rendered hydrophobic via UV-irradiated protein corona formation.
• Hanging drop 3D spheroid culture was performed on the modified paper substrate.
• In-situ analyses included drug testing, secreted protein detection, and fluorescence staining.
• A networked hanging drop chip was fabricated using wax-patterned microfluidics for controlled interactions.

Main Results:

• UV-treated paper exhibited hydrophobicity and reduced nonspecific adsorption while maintaining porosity.
• The platform successfully supported 3D spheroid culture and various in-situ analyses without disturbing spheroids.
• Networked chips allowed for controlled well-to-well interactions, mimicking physiological conditions.
• Demonstrated feasibility of studying nutrient gradients and drug effects on 3D spheroids cultured on paper.

Conclusions:

• UV-modified protein corona on cellulose paper creates a biofouling-resistant surface for 3D cell culture.
• The paper-based system offers a low-cost, scalable platform for "body-on-a-chip" applications.
• This technology enables high-throughput screening and analysis of 3D spheroids.