Significance Statement
Nanoparticle immobilization in the microfluidic chips is extremely important since their separation and recycling from a mixture are laborious and troublesome. Inspired by the mucus-covered feeding system of the clam, we proposed a novel biomimetic method to immobilize nanoparticles by using adhesive tape as the microfluidic substrate.
To verify the feasibility of this method, we processed the bond strength test, the shear stress test and the SERS detection. All the results proved this method simple and effective. The bond strength between PDMS and the common adhesive tape is able to resist a flow rate of 225 μL/min, high enough for many microfluidic applications. TiO2 nanoparticles immobilized on the adhesive tape substrate showed a stronger resistance to the shear stress than that on the glass substrate. Moreover, we immobilized the Au nanorods for the detection of R6G in various concentrations, demonstrating its usefulness for biochemical sensing applications. This immobilization method with simple, cheap and replaceable nature may find applications in various fields, especially disposable sensors, biocatalyses and biosyntheses.
Detailed highlights are listed as follows:
- Seal easily, without bonding process.
- Flexible.
- Simple fabrication.
- Better immobilization results.
- Cheap, recyclable and disposable.
Figure Legend: Nanoparticle immobilization of the adhesive tape substrate by mimicking the clam. (A) Clam internal anatomic diagram. (B) Capture of floating particles by the gill secreted mucus. (C) Optical image of the fabricated microfluidic chips. The inset illustrates the flexibility of this chip. (D) Bright field image of TiO2 nanoparticles on the adhesive tape substrate.
Journal Reference
Sensors and Actuators B: Chemical, Volume 222, January 2016, Pages 106–111.
Xiaowen Huang1,2, Yujiao Zhu1,2, Xuming Zhang1,2 , Zhiyong Bao2, Dang Yuan Lei2, Weixing Yu3, Jiyan Dai2, Yu Wang2
[expand title=”Show Affiliations”]- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, PR China
- Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong SAR, PR China
- State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Chang Chun, PR China [/expand]
Abstract
Immobilization of the suspended nanoparticles is essential for many microfluidic applications. This work reports a novel biomimetic method to immobilize nanoparticles by using a common adhesive tape as the substrate of microfluidic chip. It mimics the clams’ feeding system that utilizes the mucus (i.e., sticky fluid) to capture small phytoplankton particles in water. This work proves experimentally that this method has a better immobilization effect and a stronger shear stress resistance than the traditional methods using hard glass substrates. Moreover, we have applied this method to immobilize Au nanorods for the detection of R6G of various concentrations using the surface-enhanced Raman scattering (SERS) effect. This method enjoys several major merits: the sticky adhesive tape can seal the microfluidic structure easily, avoiding the bonding process; the immobilization is easy and environmental friendly, without the need for expensive reagents or complex processes; the adhesive tape substrate allows the flexibility of microfluidic chips; and the adhesive tape substrate can be stripped off for off-chip detection and can be replaced easily for the reuse of microfluidic structures. With these, the biomimetic method may find potential applications in environmental sensing, biocatalysis and biosynthesis using microchips.
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