Microfluidic Processes for Synthesis of Plasmonic Nanomaterials

Ph.DDOCTOR OF PHILOSOPH

Performance evaluation of HCOOH micro-fluidic fuel cell using Ni wire electrode

A membrane-free low cost microfluidic fuel cell (μFFC) consisting a trident shaped channel is molded into a poly(dimethyl siloxane) block and Ni wires affixed therein that doubled up as the catalyst and electrical connectors. Streams of aqueous acidic solutions of formic acid as the anolyte (fuel), KMnO4 as the catholyte (oxidant) and an acid electrolyte, flown through the respective channels at a constant rate ensured laminar flow across the length of the channels, while being in contact with the Ni wires, thereby tapping its’ catalytic activity for good electrochemical performance. The effect of varying fuel or oxidant concentration on the μFFC performance is studied. In the chronopotentiometric mode, the high catalytic activity of Ni allows high currents of the order of 1.25 mA to be sustained by the cell, particularly when the surface is fresh, and this current drops when the deposition of Mn, K, and S occurs. A flow rate of 150 μL/min. is found to be optimal, as the highest open-circuit voltage (OCV) of 1.33 V is attained at this flow rate. While the cell performance is largely unaffected by formic acid concentration, but it is controlled by KMnO4 concentration. Higher oxidant concentrations yielded higher OCVs, due to more amount of the five-electron reaction, occurring at the cathode enhancing the charge separation and hence the OCV. DRT studies of the EIS data resolved two different time constants for the anodic and cathodic processes. The μFFC delivers a maximum power density of 2.1 mW/cm2 and a stable current of 3.5 mA/cm2 for more than 10 min. at 0.6 V, thus validating its deployment in a variety of applications like diagnostic devices and as an independent power supply for MEMS devices

METHOD OF SYNTHESIZING COLLOIDAL NANOPARTICLES

US20110215277A1Published Applicatio

Effect of dean flows on sub-micron particles in low aspect ratio microchannels - analysis of dff

We present an analysis of the microfluidic Dean flow fractionation (DFF) method in low aspect-ratio spiral chip for high concentrations (> 106 particles /mL) of sub-micron (1-3 μm) particles. We systematically analyze the particle stream profile (i.e. thickness and distance from the channel wall) as a function of downstream channel length for step-wise increase in the fluid velocity and the flow rate ratio (FRR) of the particles to the sheath fluid. © 2020 CBMS-000

Spiral microfluidics enhanced isolation of epithelial cells from infected mice urine

Spiral microfluidics has been used in this study to isolate infected epithelial cells containing intracellular bacterial communities (IBCs) from other cells (RBCs, WBCs, and bacteria), in urine. Epithelial cells in human urine are 20 μm to 160 μm in size and hence traditional size based spiral microfluidic isolation cannot be used effectively. We isolated ~60% of epithelial cells by combining Dean Flow Fractionation with switched focusing mode at \textgreater 98% purity. We then use the proposed method for the isolation of epithelial cells from infected mice urine and show the presence of IBCs in the isolated cells as a proof of concept. © 2020 CBMS-000

Recent advances in heterogeneous micro-photoreactors for wastewater treatment application

Micro-photoreactor is a miniaturized photoreactor that integrates the advantages of microfluidics into a conventional photoreactor. Miniaturized photoreactors for wastewater treatment require relatively small quantities of photocatalyst material (femtolitre to nanolitre) and provide unique features such as high surface to volume ratio, better control of reaction parameters and efficient heat and mass transfer. The thin layer of photocatalyst in the microreactor, allows less photon loss and uniform light distribution, making it suitable for photocatalytic wastewater treatment applications. The focus of this review is the recent advancement in the area of microfluidic reactors for heterogeneous photocatalysis with details of reactor design principles, typical reactor configurations, reactor fabrication protocols, choice of reactor material and effect of process parameters such as flow rate, concentrations, light intensity, channel length on the photocatalytic reaction. We also discuss how the limitations faced by conventional photoreactors are addressed by micro-photoreactors in the context of wastewater treatment

Amplification curve showing the extraction triplicates listed in Table 4 marked using the initial concentration of SA spiked in whole blood.

Amplification curve showing the extraction triplicates listed in Table 4 marked using the initial concentration of SA spiked in whole blood.</p

S2 Fig -

PCR amplification curve over the entire linear dynamic range of concentration of 9ng to 900 fg for (a) spa marker in the red channel using TEXAS (b) mecA marker in the pink channel using CY5. PCR amplification curve for spa and mec markers. (DOCX)</p

Primers’ and probes’ concentrations for optimised multiplex assay.

Primers’ and probes’ concentrations for optimised multiplex assay.</p