Characterizing stability of “click” modified glass surfaces to common microfabrication conditions and aqueous electrolyte solutions

Abstract

Microfluidic and nanofluidic systems are dominated by fluid-wall interactions due to enormous surface-area-to-volume ratios in these devices. Therefore, strategies to control wall properties in a reliable and repeatable manner can be important for device operation. Chemical modification of surfaces provides one such method. However, the stability of the surface adhered layers under fabrication and likely device operating conditions have not been evaluated in depth. This paper presents the stability analysis of three surface layers used in the 'click' chemistry methodology for surface modification. The three surface layers have bromo, amine, and methyl termination on glass surfaces. All three surface groups are exposed to various wet and dry conditions including acid, base, solvent, electrolyte buffer solutions, oxidative plasmas, UV light, and thermal processing conditions. Contact angle measurements, X-ray photoelectron spectroscopy, and atomic force microscopy were used to quantify the stability of the adhered surface layers. The data show that the brominated surface was stable to most test conditions, while both the amine and methyl surface layers were stable to a narrower set of test conditions.

Design, fabrication and characterisation of Si‐based capillary‐driven microfluidic devices

“…Therefore, the SAM deposition on the device provides a good and long-term method for device surface modification. This result is consistent with the reported azide silane-modified surfaces on glass or polymer substrates [23,32]. Stable and hydrophilic device surface ensures the flexibility of the capillary fluidic control.…”

Effect of surface modification on interfacial nanobubble morphology and contact line tension

“…[52][53][54][55] Borosilicate glass disks, 25 mm in diameter (VWR, Chicago, IL) were initially degreased with acetone, isopropanol (IPA), deionized (DI) water (Millipore 18.2 MΩ), and blow-dried using a constant stream of dry, filtered air. [52][53][54][55] Borosilicate glass disks, 25 mm in diameter (VWR, Chicago, IL) were initially degreased with acetone, isopropanol (IPA), deionized (DI) water (Millipore 18.2 MΩ), and blow-dried using a constant stream of dry, filtered air.…”

“…[52][53][54][55] Borosilicate glass disks, 25 mm in diameter (VWR, Chicago, IL) were initially degreased with acetone, isopropanol (IPA), deionized (DI) water (Millipore 18.2 MΩ), and blow-dried using a constant stream of dry, filtered air. A well-established degrease and cleaning procedure 54,55 was used just prior to imaging nanobubbles on polycarbonate to eliminate any contamination. Following the IPA sonication, excess IPA was removed and the glass disks were cleaned using a piranha solution (4:1 H2SO4/H2O2 by volume) for 30 min.…”

“…Functionalization of the borosilicate glass substrates follows from several previous reports showing reliable preparation of surface layers. [52][53][54][55] Borosilicate glass disks, 25 mm in diameter (VWR, Chicago, IL) were initially degreased with acetone, isopropanol (IPA), deionized (DI) water (Millipore 18.2 MO), and blow-dried using a constant stream of dry, filtered air. Then, the glass disks were placed in a staining rack and sonicated in IPA for 10 min.…”

Cross‐flow microfiltration for isolation, selective capture and release of liposarcoma extracellular vesicles

“…Then, a 5% glutaraldehyde solution in 1X phosphate buffer saline (PBS; Corning) was incubated for 30 min in the microchannel followed by treating the channel with 50 μg/ml of primary antibody anti‐CD63 (Ancell) diluted in 1X PBS at 4°C for 8 h. Finally, the separation channel was filled with 1X PBS followed by 50 μl of 1X PBS placed at both ports of the separation channel to avoid drying and the device was stored at 4°C until further use (Hisey et al., 2018). Surface functionalization relies on several previous reports including the use of the anti CD‐63 antibody for immunoaffinity capture of EVs (Long et al., 2006; Prakash & Karacor, 2011; Prakash et al., 2007, 2009; Wu et al., 2010).…”