On-Flow Immobilization of Polystyrene Microspheres on β-Cyclodextrin-Patterned Silica Surfaces through Supramolecular Host–Guest Interactions

Abstract

Species-specific isolation of microsized entities such as microplastics and resistant bacteria from waste streams is becoming a growing environmental challenge. By studying the on-flow immobilization of micron-sized polystyrene particles onto functionalized silica surfaces, we ascertain if supramolecular host–guest chemistry in aqueous solutions can provide an alternative technology for water purification. Polystyrene particles were modified with different degrees of adamantane (guest) molecules, and silica surfaces were patterned with β-cyclodextrin (β-CD, host) through microcontact printing (μCP). The latter was exposed to solutions of these particles flowing at different speeds, allowing us to study the effect of flow rate and multivalency on particle binding to the surface. The obtained binding profile was correlated with Comsol simulations. We also observed that particle binding is directly aligned with particle’s ability to form host–guest interactions with the β-CD-patterned surface, as particle binding to the functionalized glass surface increased with higher adamantane load on the polystyrene particle surface. Because of the noncovalent character of these interactions, immobilization is reversible and modified β-CD surfaces can be recycled, which provides a positive outlook for their incorporation in water purification systems.

COvalent monolayer patterns in Microfluidics by PLasma etching Open Technology – COMPLOT

“…S1, ESI †), 22 or for capturing adamantane modified microparticles on flow through host-guest chemistry. 23 Here, we validated the functionalization of β-CD patterns on the glass surface within the fabricated microfluidic device through addition of Cy5-Ad 2 , which allowed us to use fluorescence microscopy to study the immobilization and release of Cy5-Ad 2 under flow. In addition, the binding kinetics of Cy5-Ad 2 were also determined in a multichannel COMPLOT device via analysis of different Cy5-Ad 2 concentrations on one microfluidic slide.…”

“…The microfluidic device can be used for various applications with aqueous or light organic solvents such as ethanol and methanol, however, use of highly hydrophobic solvents which swell PDMS, such as toluene or chloroform should be avoided. Through this enabling technology for fabrication of patterned PDMS/glass hybrid microfluidic devices, a way is opened for researchers less experienced in surface functionalization and working on different fields ranging from (bio) sensing applications, such as immobilization of micron-sized entities, 23 to analytical chemistry and medical applications like lab-or organs-on-achip. 35,36…”

Plasma Etching for Fabricating Microfluidic Devices with Patterned Monolayers

“…19 Through supramolecular host-guest chemistry, the inside of β-CD's hydrophobic cavity (host) can be used for immobilization of guest functionalized molecules, such as Cyanine 5-diadamantane (Cy5-Ad2), 20 or for capturing adamantane modified microparticles on flow through hostguest chemistry. 21 Here, we validated the functionalization of β-CD patterns on the glass surface within the fabricated microfluidic device through addition of Cy5-Ad2, which allowed us to use fluorescence microscopy to study the immobilization and release of Cy5-Ad2 under flow. In addition, the binding kinetics of Cy5-Ad2 were also determined in a multichannel COMPLOT device via analysis of different Cy5-Ad2 concentrations on one microfluidic slide.…”

“…28,29 Furthermore, the versatility of the adamantane-β-CD couple is similar to the (strept)avidin-biotin couple, and therefore allows for incorporating (bio)molecules functionalized with adamantane on the surface. Through this enabling technology for fabrication of patterned PDMS/glass hybrid microfluidic devices, a way is opened for researchers less experienced in surface functionalization and working on different fields ranging from (bio) sensing applications, such as immobilization of micron-sized entities, 21 to analytical chemistry and medical applications like lab-or organs-on-a-chip. 30,31…”