Designing and Fabrication of a Microfluidic Device Using a 3D Printer and It s Application Detection of Single Nucleotide Polymorphism by Luminal Coated Platinum Nanoparticles in Bipolar Electrochemical Systems for the

A SNP is a single nucleotide variation at a specific location in the genome that is by definition found in more than 1% of the population [1]. The development of simple, inexpensive, hand-held, user-friendly biosensor for High throughput and multiplexed genotyping of various single nucleotide polymorphisms (SNPs) in a single run experiment by a non-specialist user is the main challenge in the analysis of DNA [2]. In the present manuscript, a novel wireless electrochemiluminescence (ECL) DNA sensor is introduced for genotyping of different SNPs on the basis of ECL of luminol/hydrogen peroxide system on a bipolar electrode (BPE) platform that is integrated whit microfluidic channels constructed with three-dimensional printers. In a bipolar electrochemistry (BE), a driving potential is applied through an electrolyte solution containing conducting object (bipolar electrode; BPE) using two deriving electrodes connected to a power supply. This driving potential causes a potential drop in the solution and therefore induces a potential difference along the length of the BPE. If this potential difference is sufficient, the faradaic reactions simultaneously occur at the ends of BPE [3]. Recently because of simplicity, low-cost, ease of operation and device fabrication, BE has been applied in a number of interesting analytical studies. Especially this method does not require a direct electrical connection between BPE and the external power supply (wireless), as a result, using BE allows employing large number of BPE arrays. As well as, integration of BPE and ECL (BPE-ECL) have drawn much more attention in bioanalysis. The wireless nature of the BPE and no need for the light source in ECL, not only simplifies detection system for BPE-ECL, but also, improves detection limit and sensitivity, due to no scattered light in the sample and no excitation source fluctuations. The luminol along with hydrogen peroxide (H2O2) as its coreactant is a well-known system to produce strong ECL at positive potentials, under a variety of experimental conditions. Recently, the catalytic properties and high loading amount of luminol functionalized nanoparticles for ECL emission, instead of the solution of luminol, have attracted many interest of the researchers. Then we use luminol-functionalized platinum nanoparticles [4]. the integration of BPE systems by microfluidic devices increases the sensitivity of the methods, as well as reducing the consumption of materials and energy. microfluidics is the science and technology of systems that process or manipulate small (10 -9to 10 -18litres) amounts of fluids, using channels with dimensions of tens to hundreds of micrometers. The first applications of microfluidic technologies have been in analysis, for which they offer a number of useful capabilities: the ability to use very small quantities of samples and reagents, and to carry out separations and detections with high resolution and sensitivity; low cost; short times for analysis; and small footprints for the analytical devices [5]. After modification of anodic poles of the BPEs with the DNA probe and its hybridization with the targets, genotyping of various SNPs is carried out by exposing them to different monobase modified luminol-platinum nanoparticles (M-L-PtNPs). Upon the hybridization of M-L-PtNPs to mismatch sites, the ECL of luminol is followed using a photomultiplier tube (PMT). In this method, the ECL of luminol molecules was observed for mismatch sites but in the presence of a complementary strand, no ECL signal is observed. Similarly, for the different concentrations of the DNA strand, the observed light has a trend.In this work, for the first time, a novel hybrid architecture of CeO2-Au nanofibers (CeO2-AuNFs) and single-crystalline RuO2 nanowires (RuO2NWs) have been synthesized by a combination of electrospinning and thermal annealing process. The CeO2-Au hybrid nanofibers were fabricated by the electrospinning technique and then annealed in air [3]. The amorphous Ru(OH)3 precursors at relatively low temperature were efficiently converted into highly single-crystalline RuO2NWs on electrospun CeO2-AuNFs. The electrospun CeO2-AuNFs, RuO2NWs–CeO2-AuNFs and other nanostructure were characterized by different methods such as field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), energy dispersive X-ray analysis (EDS) and fourier transform infrared spectroscopy (FT–IR). Novel RuO2NWs–CeO2-AuNFs hybrid architecture in combination with graphite oxide (GO) and functionalized multiwalled carbon nanotubes (f-MWCNTs) further employed to modify screen printed carbon electrode (SPCE (in order to develop a sensitive electrochemical method with suitable properties for the simultaneous determination of ascorbic acid (AA), dopamine (DA) and serotonin (5-HT). The dependence of the oxidation peak currents on the pH of the solution, amount of modifier, scan rate and concentration of the analytes was studied to optimize the experimental conditions.Under the optimum operating conditions, linear calibration curves were obtained in the range of 0.5–100, 0.01–120 and 0.01–150 μM with a detection limit of 160, 2.8 and 2.4 nM for AA, DA and 5-HT, respectively. The proposed electrochemical sensor provided a good performance for the simultaneous determination of AA, DA and 5-HT by not only significantly improved their current responses, but also decreased the overpotentials as well as resolved the overlapping of the oxidation peak potentials. This sensor was successfully applied for the determination of AA, DA and 5-HT in biological fluids and pharmaceutical samples.