Surface engineering of microchannel walls for protein separation and directed microfluidic flow

Area of Science:

• Materials Science
• Analytical Chemistry
• Biotechnology

Background:

• Surface modification in microfluidic devices for protein retention is challenging due to fabrication incompatibilities.
• Existing methods often struggle to integrate derivatization techniques with microdevice construction.

Purpose of the Study:

• To review recent advancements in simple and rapid surface chemistry engineering for microfluidic channels.
• To explore the use of press-fit microdevices for selective protein retention and microscale separations.

Main Methods:

• Fabrication of press-fit microdevices by placing a glass fiber on a polydimethylsiloxane (PDMS) film.
• Pressing the PDMS film onto a derivatized silicon wafer or microscope slide (e.g., with octadecyltrichlorosilane (ODS)).
• Formation of elliptically shaped channels around the fiber upon film adhesion.

Main Results:

• The combined hydrophilic glass fiber and hydrophobic microchannel surfaces create a narrow liquid boundary layer.
• This boundary layer facilitates sample contact with separation media, leading to selective protein retention.
• Diverse fiber chemistries allow for rapid fabrication of microchannels acting as microscale stationary phases.

Conclusions:

• Press-fit microdevices offer a facile approach to engineer microfluidic surfaces for selective protein binding.
• The tunable surface properties enable diverse microscale separation applications.
• This technique provides a versatile platform for developing novel microfluidic separation media.