Superhydrophobic Paper in the Development of Disposable Labware and Lab-on-Paper Devices

Abstract

Traditionally in superhydrophobic surfaces history, the focus has frequently settled on the use of complex processing methodologies using nonbiodegradable and costly materials. In light of recent events on lab-on-paper emergence, there are now some efforts for the production of superhydrophobic paper but still with little development and confined to the fabrication of flat devices. This work gives a new look at the range of possible applications of bioinspired superhydrophobic paper-based substrates, obtained using a straightforward surface modification with poly-(hydroxybutyrate). As an end-of-proof of the possibility to create lab-on-chip portable devices, the patterning of superhydrophobic paper with different wettable shapes is shown with low-cost approaches. Furthermore, we suggest the use of superhydrophobic paper as an extremely low-cost material to design essential nonplanar lab apparatus, including reservoirs for liquid storage and manipulation, funnels, tips for pipettes, or accordion-shaped substrates for liquid transport or mixing. Such devices take the advantage of the self-cleaning and extremely water resistance properties of the surfaces as well as the actions that may be done with paper such as cut, glue, write, fold, warp, or burn. The obtained substrates showed lower propensity to adsorb proteins than the original paper, kept superhydrophobic character upon ethylene oxide sterilization and are disposable, suggesting that the developing devices could be especially adequate for use in contact with biological and hazardous materials.

Bio-Based Coatings for Paper Applications

“…The surface wettability of these papers (water contact angle 153° ± 0.7°) can be further controlled by argon plasma treatment in certain regions by the application of a mask. These kind of papers can potentially be used as disposable labware and lab-on-paper devices, having the advantage of extremely low-cost material, with self-cleaning and water resistance properties, and may be suitable for handling biological and hazardous substances [159].…”

Bio-Inspired Extreme Wetting Surfaces for Biomedical Applications

“…Open-channel droplet-based microfluidic systems have several benefits compared with conventional closed-channel based microfluidic devices in terms of easy introduction of sample liquid, low sample and energy consumptions, and rapid chemical and biological reactions [155,156,157,158,159,160,161,162,163,164,165]. Manipulation of droplet motions is most important for the open-channel droplet-based microfluidic system.…”

Robust Non-Wetting PTFE Surfaces by Femtosecond Laser Machining

“…Gentile et al (2011, 2012) have shown that dilute solutions can be concentrated onto the liquid-supporting solid of air-trapping superhydrophobic surfaces to allow for detection of low concentration solutes which is of interest e.g., for the early detection of cancer cells [15,16]. Sousa and Mano (2013) have illustrated the fabrication of superhydrophobic paper and its application for various sustainable laboratory apparatus, which support the storage, transfer and mixing of aqueous media [17]. The above examples illustrate that there are many possible applications for extremely non-wetting surfaces.…”