Biocompatibility in inkjet-printed paper-based microelectronic biosensors

摘要

Inkjet-printing supports environmentally friendly manufacturing of printed electronics and enables rapid prototyping with low material waste. In this work, inkjet-printed conductive tracks on ethyl 2-cyanoacrylate (superglue) is compared to tracks printed on paper. This work will provide solutions for disposable biosensing, where the biocompatibility of versatile superglue is important. The emphasis throughout the work is on developing a biocompatible device. Dog-bone structures with different line widths were printed on paper and superglue, providing comparative results obtained from dimensional and electrical characterisation. On average the tracks printed on superglue have a 2.6 times higher resistivity than those printed on paper, but are acceptable for printed electronics networks. When considering a lumped component ac model, the 500 μm tracks on superglue have a series inductance of 2.6 nH, while the 4-point Kelvin probe characterisation of the 100 μm and 250 μm tracks printed on superglue show a capacitive equivalent impedance with capacitance values of 2.8 μF and 2.6 μF respectively. The 100 μm, 250 μm and 500 μm tracks printed on paper have inductance values of 1.20 nH, 11.30 nH and 14.8 nH, respectively. All printed tracks have linear frequency operational ranges larger than 1 MHz. A biocompatibility test was performed with Escherichia coli (E. coli) O157:H7. The silver nanoparticle ink proved to be antibacterial, while paper, superglue and gold nanoparticle ink was biocompatible. These results provide information assisting the design process for bio applications that require conformal and multi-substrate printing.