A traveling surface acoustic wave-based micropiezoactuator: A tool for additive- and label-free cell lysis.

We propose a traveling surface acoustic wave (TSAW)-based microfluidic method for cell lysis that enables lysis of any biological entity, without the need for additional additives. Lysis of cells in the sample solution flowing through a poly (dimethyl siloxane) microchannel is enabled by the interaction of cells with TSAWs propagated from gold interdigitated transducers (IDTs) patterned onto a LiNbO3 piezoelectric substrate, onto which the microchannel was also bonded. Numerical simulations to determine the wave propagation intensities with varying parameters including IDT design, supply voltage, and distance of the channel from the IDT were performed. Experiments were then used to validate the simulations and the best lysis parameters were used to maximize the nucleic acid/protein extraction efficiency (>95%) within few seconds. A comparative analysis of our method with traditional chemical, physical and thermal, as well as the current microfluidic methods for lysis demonstrates the superiority of our method. Our lysis strategy can hence be used independently and/or integrated with other nucleic acid-based technologies or point-of-care devices for the lysis of any pathogen (Gram positives and negatives), eukaryotic cells, and tissues at low voltage (3 V) and frequency (33.17 MHz), without the use of amplifiers.

A multiplex Taqman PCR assay for MRSA detection from whole blood.

Methicillin-resistant Staphylococcus aureus (MRSA) causes a wide range of hospital and community-acquired infections worldwide. MRSA is associated with worse clinical outcomes that can lead to multiple organ failure, septic shock, and death, making timely diagnosis of MRSA infections very crucial. In the present work, we develop a method that enables the positive enrichment of bacteria from spiked whole blood using protein coated magnetic beads, followed by their lysis, and detection by a real-time multiplex PCR directly. The assay targeted bacterial 16S rRNA, S. aureus (spa) and methicillin resistance (mecA). In addition, an internal control (lambda phage) was added to determine the assay's true negative. To validate this assay, staphylococcal and non-staphylococcal bacterial strains were used. The three-markers used in this study were detected as expected by monomicrobial and poly-microbial models of the S. aureus and coagulase-negative staphylococci (CoNS). The thermal cycling completed within 30 mins, delivering 100% specificity. The detection LoD of the pre-processing step was ∼ 1 CFU/mL from 2-5mL of whole blood and that of PCR was ∼ 1pg of NA. However, the combined protocol led to a lower detection limit of 100-1000 MRSA CFUs/mL. The main issue with the method developed is in the pre-processing of blood which will be the subject of our future study.

Extracellular biosynthesis of CuO-TiO2 nanocomposites using Alcaligenes aquatilis for the photodegradation of reactive and azo dyes under visible light irradiation.

In this study, CuO/TiO2 nanocomposites were biologically synthesized using cell-free supernatant (CFS) of Alcaligenes aquatilis growth culture by two-step synthesis method, one-pot method with sequential addition of precursors, and one-pot method with simultaneous addition of precursors. The one-pot method with simultaneous addition of precursors was found to be the best method for the synthesis in terms of degradation of reactive blue-220 (RB-220) and acid yellow-17 (AY-17) dyes under visible light irradiation. CuO/TiO2 nanocomposite was found to have the crystallite size of 14.7nm and the bandgap energy of 2.5 eV. The effect of synthesis parameters such as synthesis time, pH of CFS, and the ratio of Cu to Ti in the synthesis mixture on the photocatalytic degradation efficacy of these nanocomposite structures under visible light irradiation was studied. The optimum conditions for the synthesis of CuO/TiO2 nanocomposite particles by one-pot method with simultaneous addition of precursors were found to be pH 12 of CFS, synthesis duration of 24 h, and molar ratio of Cu to Ti in the synthesis mixture as 1:22 for RB-220 dye and 1:25 for AY-17 degradation. CuO/TiO2 nanocomposite particles synthesized under the optimum conditions and without any calcination could degrade RB-220 and AY-17 dyes completely in 120 min and 150 min, respectively. The kinetics of degradation of RB-220 and AY-17 by CuO@TiO2 nanocomposite particles followed first-order kinetic model with rate constant of 0.028 min-1 and 0.018 min-1, respectively.

Current commercial dPCR platforms: technology and market review.

Digital polymerase chain reaction (dPCR) technology has provided a new technique for molecular diagnostics, with superior advantages, such as higher sensitivity, precision, and specificity over quantitative real-time PCRs (qPCR). Eight companies have offered commercial dPCR instruments: Fluidigm Corporation, Bio-Rad, RainDance Technologies, Life Technologies, Qiagen, JN MedSys Clarity, Optolane, and Stilla Technologies Naica. This paper discusses the working principle of each offered dPCR device and compares the associated: technical aspects, usability, costs, and current applications of each dPCR device. Lastly, up-and-coming dPCR technologies are also presented, as anticipation of how the dPCR device landscape may likely morph in the next few years.