A combinative approach for the selective cellularization of human capillary-sized microchannels

Area of Science:

• Biomaterials Engineering
• Cell Biology
• Microfluidics

Background:

• Controlled cellularization of microchannels, especially those with capillary dimensions, is a significant hurdle in creating accurate in vitro vascular models.
• Existing methods struggle with reliable and spatially selective endothelialization of microchannels below several tens of micrometers.

Purpose of the Study:

• To develop a novel strategy for selective endothelial cell seeding in microchannels as small as 20 µm.
• To overcome the limitations of current techniques in achieving capillary-level endothelialization for in vitro vascular applications.

Main Methods:

• A combined approach using soft lithography, thin metal film deposition, and gas-phase surface modification.
• Creation of micrometric chemical selectivity within microfabricated environments to define precise cell-adhesive paths.
• Alignment of 15-µm-wide adhesive paths with SU-8 microchannels for selective inner-surface functionalization.

Main Results:

• Demonstrated exclusive endothelial cell adhesion within targeted 20 µm microchannels.
• Confirmed physicochemical contrast between patterned and non-patterned regions using SEM and AFM.
• Achieved robust and reproducible cellularization without complex flow-based patterning or post-bonding treatments.

Conclusions:

• The developed method successfully enables selective endothelialization of capillary-sized microchannels.
• This technique overcomes a critical barrier in microvascular fabrication, offering a versatile platform for capillary-scale in vitro models.
• Provides precise control over cell adhesion in microfluidic devices for advanced biological research.