Droplet Manipulation on Bioinspired Slippery Surfaces: From Design Principle to Biomedical Applications

Abstract

Droplet manipulation with high efficiency, high flexibility, and programmability, is essential for various applications in biomedical sciences and engineering. Bioinspired liquid‐infused slippery surfaces (LIS), with exceptional interfacial properties, have led to expanding research for droplet manipulation. In this review, an overview of actuation principles is presented to illustrate how materials or systems can be designed for droplet manipulation on LIS. Recent progress on new manipulation methods on LIS is also summarized and their prospective applications in anti‐biofouling and pathogen control, biosensing, and the development of digital microfluidics are presented. Finally, an outlook is made on the key challenges and opportunities for droplet manipulation on LIS.

On-chip droplet analysis and cell spheroid screening by capillary wrapping enabled shape-adaptive ferrofluid transporters

“…Precise and lossless control of samples ensures the reliability of droplets as microreactors for sample processing and analysis in cell engineering and molecular diagnosis. 14,20,25 We illustrated the reliability of the transporter manipulation by adopting the polymerase chain reaction (PCR). As shown in Fig.…”

“…13 To realize high-dimensional control, a toolbox that includes the utilization of various external stimuli, such as electric, 14,15 magnetic, 16 acoustic, 17 and photothermal 18,19 stimuli, has been established. 20 Electrowetting on dielectric (EWOD) technique has revolutionized many application domains in a programmable and digital fashion. 21 However, EWOD suffers from restricted actuation volume and substrate/electrode fouling.…”

“…23,31 A lack of capability arises when the goal is to integrate the manipulation method into a programmed digital control system. 20 Compared with solid substrates, the flexibility of droplet manipulation can be significantly extended when it is performed on ferrofluid infused substrates. 32,33 However, droplets moving on ferrofluid-infused surfaces still experience high interfacial drag, 34 and the exposure of droplets to an open environment is not feasible for bioanalytical applications where long-term cell incubation and in situ observations are needed.…”

Photoelectric synergistic anisotropic slippery interface for directional droplets manipulation

“…The directional transport of liquids plays an essential role in industrial production and human life and is widely used in many fields such as oil–water directional separation, 1–5 microfluidic chips, 6–8 directional sensing, 9 biological detection 10,11 and anisotropic self-cleaning. 12–15 Directional transportation and manipulation of liquid droplets mainly depend on anisotropic interfaces with special wettability, such as anisotropic superhydrophobic interfaces 16–19 and anisotropic slippery interfaces.…”

Abrasion‐Resistant and Enhanced Super‐Slippery Flush Toilets Fabricated by a Selective Laser Sintering 3D Printing Technology

“…[7] When the contaminants fall onto the substrate surface, they first encounter the lubricant film rather than the substrate surface, which can greatly reduce the interfacial adhesion and be widely applied in the antifouling, self-cleaning, and anti-icing fields. [11][12][13][14][15] Inspired by this concept, a thick polymeric layer (%1 μm) was coated on the toilet to absorb lubricant and then reduce the waste adhesion. [3] However, the super-slippery layer would lose its functionality after about 35 times the synthetic feces impact.…”