Bioinspired Superwettable Microspine Chips with Directional Droplet Transportation for Biosensing

Abstract

Directional droplet transportation without extra energy input remains a challenge in microfluidic biochips for clinical detections. Herein, inspired by the water-collecting behaviors on the cactus spine, we fabricate nanomaterial-based superwettable microspine (SMS) chips. The bioinspired SMS chips are capable of spontaneous and directional droplet transportation by synergistically combining geometric asymmetry and surface superhydrophilicity. Based on theoretical models, the gradient of the Laplace pressure arising from the geometric asymmetry of the SMS chip can dominate the directional transportation of the droplet, and the superhydrophilicity of the nanomaterial-based microspine can also contribute to the droplet self-transportation. The multimicrochannel SMS chips provide a simple and energy efficient technology to realize accurate detection of serum prostate-specific antigen (PSA) from prostate cancer patients, showing great potential as a biosensing platform for clinical applications. We believe that our bioinspired superwettable two-dimensional conical surface will offer effective means for the design of smart microfluidic devices and have great potential applications in multicomponent biosensing and clinical detection.

Biomimetic Nanostructure Platform for Cancer Diagnosis Based on Tumor Biomarkers

“…For instance, in the open-channel microfluidic system for diagnosis, which requires droplet transportation, many natural behaviors or properties such as Nepenthes alata, spider silk, shorebird beak, and cactus spine have engendered ideas for droplet transportation, leading to different approaches that apply a different gradient of surface energy or the asymmetrical design of the substrate that can drive the droplet (Wu et al, 2019). Chen et al utilized the behavior of the cactus spine that was capable of directional droplet transportation and fabricated superwettable microspine (SMS) chips with an asymmetrical geometric design, including microchannel and microwell with a superhydrophilic property on the superhydrophobic surface (Gong X. et al, 2020;Guan et al, 2020;Han et al, 2020;Wei D. et al, 2020), which allowed directional droplet transportation by both geometric shape and superhydrophilic property (Figure 4A) (Chen et al, 2020). To better understand the transportation behavior of water droplets, different geometric gradients were measured by the optical contact angle measuring instrument, which revealed that FIGURE 4 | (A) Directional droplet transportation on the superwettable microspine (SMS) chip inspired by the cactus spine.…”

“…Sensitivity of the SMS chip with increasing concentration of PSA. Specificity examination of the SMS by setting various conditions, including PSA, PSA+CEA+HAS, HAS, carcinoembryonic antigen (CEA), and negative control (Chen et al, 2020). (B) A schematic of fabrication of the SA-DTP, biotin-linker DNA, AS1411 aptamer, and catalytic hairpin assembled (CHA) probes were connected by streptavidin.…”

Bioinspired superwetting surfaces for biosensing

“…Except for the well‐known fog harvesting, the beetle‐inspired patterned wettable surfaces have been also used for biosensing 88‐91 . The microdroplets can be well anchored on (super)hydrophilic points in small regions.…”

Bioinspired Tunable Structural Color Film with Janus Wettability and Interfacial Floatability towards Visible Water Quality Monitoring

“…Superwettability, such as superhydrophobic, superhydrophilic, and tunable wettability has attracted increasing attention in recent years for their applications in self‐cleaning, anti‐fogging, anti‐icing, and so on. [ 1–5 ] To construct efficient superwettability surfaces, various approaches have been developed, including plasma treatment, layer‐by‐layer method, vapor deposition, etc. [ 6–13 ] In recent years, more attention has been paid to films with Janus wettability which have two faces with different properties.…”