Barcode Nanowires for Multiplexed Bioanalysis

Abstract

Sequential template electrochemical synthesis of multisegment nanowires with magnetic and non-magnetic segments has been extremely significant for barcoding, multiplexing and biosensing applications [1]–[3]. Especially, hard magnetic segment with high saturation magnetization and remenance materials are more convenient for multiplexing biological applications. In the present article we have synthesized three different types of magnetic barcode nanowires Co[Ni/Pt/Fe]P/Au by electrochemical deposition technique using a polycarbonate membrane with a diameter of 50 nm and functionalized with DNA for multiplexing analysis. Before synthesis of barcode nanowires, we first synthesized single segment of hard magnetic nanowires. The length of the nanowires was found to be around 6 $\mu \text{m}$ . We compared the magnetic properties of all the synthesized materials and found to be the CoPtP magnetic nanowires have higher saturation and remenence. In order to demonstrate the decoding of barcode nanowires using the magnetoresistance sensor in flow cytometry, we calculated the spatial distribution of the stray magnetic field produced by the barcode nanowire by means of finite element method (FEM) using the commercial Maxwell software. The CoPtP shows higher spatial variation compared to the CoFeP and CoNiP, which means CoPrP is most advantageous composition for the hard magnetic segment. Our main aim for synthesis of this type of nanowires is for the application of multiplex bioanalysis by magnetic method.