SPION-mediated soil DNA extraction and comparative analysis with conventional and commercial kit-based protocol

The Requirement of Genetic Diagnostic Technologies for Environmental Surveillance of Antimicrobial Resistance

Antimicrobial resistance (AMR) is threatening modern medicine. While the primary cost of AMR is paid in the healthcare domain, the agricultural and environmental domains are also reservoirs of resistant microorganisms and hence perpetual sources of AMR infections in humans. Consequently, the World Health Organisation and other international agencies are calling for surveillance of AMR in all three domains to guide intervention and risk reduction strategies. Technologies for detecting AMR that have been developed for healthcare settings are not immediately transferable to environmental and agricultural settings, and limited dialogue between the domains has hampered opportunities for cross-fertilisation to develop modified or new technologies. In this feature, we discuss the limitations of currently available AMR sensing technologies used in the clinic for sensing in other environments, and what is required to overcome these limitations.

Smartphone operable centrifugal system (SOCS) for on-site DNA extraction from foodborne bacterial pathogen

The on-site recovery of nucleic acid from foodborne bacteria is in high demand to further understand on-site molecular diagnosis, which is especially applicable in developing countries. Here, we first proposed a smartphone operable centrifugal system (SOCS) for nucleic acid extraction with the assistance of a low power consumable motor and hydrogel beads. The SOCS consists of a centrifugal motor, 3D-printed cartridge, a nucleic acid collection column, and a smartphone. The SOCS shows excellent DNA extraction performance within 6 min, and it can operate more than 100 times using a smartphone. The purified effluent DNA was accumulated in the nucleic acid collection column. The performance of the SOCS was confirmed by amplifying the recovered DNA from Escherichia coli O157:H7. Moreover, the artificially inoculated food and blood samples also confirmed the performance of SOCS. The proposed SOCS provides an on-site operable nucleic acid separation platform in terms of simplicity, easy usability, cost-effectiveness, and portability in pathogenic point-of-care diagnostics.

Isolation of nematode DNA from 100 g of soil using Fe3O4 super paramagnetic nanoparticles

An economical method for extracting nematode DNA from 100 g of soil was developed to facilitate nematode detection and quantification, and tested using the Northern root-knot nematode,Meloidogyne hapla. The method utilised enzymatic laundry detergent lysis, Fe3O4super paramagnetic iron oxide nanoparticle (SPION) capture, and polyvinylpolypyrrolidone (PVPP) purification. Resultant DNA from this SPION capture method was approximately 100-fold less but of similar quality to DNA obtained from a standard phenol procedure and a commercial DNA extraction kit. An addition of 10 mg of nanoparticles to the extraction lysate was identified to maximise DNA yield while minimising co-capture of contaminants. The detection limit of the SPION capture method was approximately 100 nematodes (100 g soil)−1. The SPION capture method extracted nematode DNA from mineral soils but requires further optimisation for extraction from high organic matter (i.e., ‘muck’) soils. The benefits of this method compared to alternative techniques are discussed.