Lysing Bacterial Spores by Sonication through a Flexible Interface in a Microfluidic System

Abstract

Cell disruptions using ultrasonic energy transmitted through a flexible interface into a liquid region has limitations because the motion of the vibrating tip is not completely transferred into the liquid. To ensure that some degree of contact will be maintained between the ultrasonic horn tip and the flexible interface, the liquid must be pressurized. The pressure conditions that yield consistent coupling between the ultrasonic horn tip and the liquid region were explored in this study by using an analytical model of the system and test fixture experiments. The nature of the interaction between the horn tip and the flexible interface creates pulses of positive pressure rises, increase in temperature, streaming flow, and almost no cavitation in the liquid. There was sufficient energy to create a cloud of microspheres, or beads, that maintain a consistent pattern of ballistic motion in the liquid. The sonication was found to be repeatable by studying video recordings of bead motion and was shown to be statistically consistent using measurements of temperature rise. Sonication of bacterial spores to obtain measurements of released nucleic acid and SEM images of damaged spores were used to verify the effects of liquid pressure on the horn-interface-liquid coupling.

Lab-on-a-chip technologies for proteomic analysis from isolated cells

“…Typical protocols for off-chip lysis include the use of enzymes, detergents or mechanical forces, but other lysis techniques may be more appropriate for integration into a microfluidic system (Belgrader 1999;Taylor et al 2001;Schilling et al 2002;Fox et al 2006). While chemical lysis generally affects all membranes in the cell, including organelles, electroporation can be used to lyse only the outer cell membrane, keeping organelles intact.…”

Fabrication of rigid microstructures with thiol-ene-based soft lithography for continuous-flow cell lysis

“…One such application is rapid and continuous-flow cell lysis in a microfluidic channel. Although a number of techniques have been demonstrated for on-chip cell lysis, including chemical, 3,4 electrical, 5,6 acoustic, 7,8 and optical, 9,10 these methods require a high residence time in the microfluidic channel, and thus cannot be used for continuous-flow processing. Only mechanical shearing of cells offers the lysis speed to enable continuous-flow processing.…”

MEMS-Based Microdevice for Cell Lysis and DNA Extraction

“…However, the fabrication process of nanostructures is complex. Other miniaturization cell lysis methods include thermal (Lee & Tai, 1999), electrical (Gao et al, 2004;Taylor et al, 2001), ultrasonication (Belgrader et al, 2000;LaMontagne1 et al, 2002), and chemical treatments (Li & Jed Harrison, 1997). These approaches have been shown to be moderately successful.…”