In the most inhospitable field environments, a lack of reliable access to electricity can further complicate sample preparation. CUBRC has been working with the Department of Defense to develop rapid, inexpensive approaches to sample prep. The company recently developed a platform for the isolation of protein, RNA, and DNA from samples by solid-phase extraction without the use of electricity.
“The chromatography platform is based on disposable transfer pipettes,” explained David Pawlowski, Ph.D., senior research scientist at CUBRC. “The resin or sorbent is built into a transfer pipette and held within by a high-density polyethylene frit.”
The platform is ideal for use in high schools, or for rapid development of purification schemes on a small scale. Using this system CUBRC has successfully demonstrated solid phase nucleic acid and protein extraction using silica as the sorbent and His-tagged protein purification with commercial metal affinity resins, according to Dr. Pawlowski. “Our platform can readily accommodate other purification strategies designed around antibody conjugates, aptamers, or nucleic acid oligomers,” he said.
While the detection of bacterial pathogens in biological samples has been the traditional province of immunological methods such as ELISA, the stability and resilience of antibodies limits their reliability.
A group led by Stephane Evoy, Ph.D., at the National Institute for Nanotechnology at the University of Alberta, is developing an alternative to antibody detection of microbes based on bacteriophages.
“Bacteriophages have a highly specific relationship with strain of bacteria,” explained Dr. Evoy. “E. coli has a specific phage, as does Salmonella, and there is no cross-reaction between the bacteriophages strains other than their specific host.”
The specificity and precision of this interaction derives from sequences contained in viral tail-spike proteins, or TSPs, which engage signature carbohydrate moieties on the bacterial cell wall. Recombinant peptides representing the TSP amino acid sequences responsible for mediating interactions with the pathogens can be coupled to magnetic beads.
“The smaller size of the TSP indeed provides more uniform coverage to the capturing surface,” noted Dr. Evoy, who added that the system has demonstrated considerable advantages in terms of speed of sample processing.
“Recovery of bacteria from milk or blood can take up to 12 hours,” according to Dr. Evoy, “but this can be reduced to 30 minutes using bacteriophage-based probes.”