• 文献标题:   In situ integration of graphene foam-titanium nitride based bio-scaffolds and microfluidic structures for soil nutrient sensors
  • 文献类型:   Article
  • 作  者:   ALI MA, MONDAL K, WANG YF, JIANG HW, MAHAL NK, CASTELLANO MJ, SHARMA A, DONG L
  • 作者关键词:  
  • 出版物名称:   LAB ON A CHIP
  • ISSN:   1473-0197 EI 1473-0189
  • 通讯作者地址:   Iowa State Univ
  • 被引频次:   19
  • DOI:   10.1039/c6lc01266c
  • 出版年:   2017

▎ 摘  要

It is challenging to integrate porous graphene foam (GF) and GF-based nanocomposites into microfluidic channels and even create microfluidic structures within these materials. This is because their irregular interior pore shape and geometry, rough exterior surface, and relatively large material thickness make it difficult to perform conventional photolithography and etching. This challenge has largely hindered the potential of using GF-based materials in microfluidics-based sensors. Here we present a simple approach to create well-defined flow-through channels within or across the GF-based materials, using a liquid-phase photopolymerization method. This method allows embedding of a nanocomposite-based scaffold of GF and titanium nitride nanofibers (GF-TiN NFs) into a channel structure, to realize flow-through microfluidic electrochemical sensors for detecting nitrate ions in agricultural soils. The unique GF-TiN nanocomposite provides high electrochemical reactivity, high electron transfer rate, improved loading capacity of receptor biomolecules, and large surface area, serving as an efficient electrochemical sensing interface with the help of immobilized specific enzyme molecules. The microfluidic sensor provides an ultralow limit of detection of 0.01 mg L-1, a wide dynamic range from 0.01 to 442 mg L-1, and a high sensitivity of 683.3 mu A mg(-1) L cm(-2) for nitrate ions in real soil solution samples. The advantageous features of the GF-TiN nanocomposite, in conjunction with the in situ integration approach, will enable a promising microfluidic sensor platform to monitor soil ions for nutrient management towards sustainable agriculture.