New diagnostic and treatment approach will require close interaction with Pathologists
There’s a novel diagnostic device designed to detect sepsis that also has to potential to engage the pathologist as part of the bedside care team. It is also an example of how nanotechnology and magnetism are being combined in ways that may support in vivo diagnosis and treatment.
Created by a research scientist at Children’s Hospital Boston, this new device uses magnetism to quickly pull disease pathogens out of infected blood. Experts predict it could become the first line of defense for sepsis, a disease which kills about 200,000 Americans each year.
The system works by drawing the patient’s blood and adding tiny magnetic beads, pre-coated with antibodies against specific pathogens, such as Candida albicans. The blood is run through a microfluidic system in which two liquid flow streams run side by side without mixing. One channel contains blood and the other contains a saline-based collection fluid. The beads bind to the pathogens. A magnet then pulls them, along with the pathogens, into the collection fluid. The collection fluid is ultimately discarded, and the cleansed blood reintroduced into the patient.
Tested with contaminated human blood, a device with four parallel collection modules achieved more than 80% clearance of fungi in a single pass, at a flow rate and separation efficiency that would be viable for clinical applications.
These results provide the first proof-of-principle that a multiplexed micromagnetic-microfluidic separation system can be used to cleanse pathogens from flowing human blood at a rate and separation efficiency that is relevant for clinical applications. Current therapeutic approaches are often suboptimal, in part, because they do not fully eliminate the pathogen, or source of deadly toxins.
Inventor Chong Wing Yung, Ph.D., and Pathologist Don Ingber, M.D., Ph.D., the Laboratory Director, estimate that a scaled-up system with hundreds of channels could cleanse the blood of an infant within several hours. Ingber noted that this blood-cleansing device works simply by removing the source of the infection, thereby enhancing the patient’s response to antibiotics.
The study, published in the journal Lab on a Chip , was funded by the Center for Integration of Medicine and Innovative Technology , Harvard University’s Center for Nanoscale Systems, and the National Nanotechnology Infrastructure Network initiative. CIMIT recently awarded a $500,000 grant to a consortium, which includes Yung, Ingber, Pathologist Mark Puder, M.D., Ph.D., Surgeon Jay Wilson, M.D. and Cambridge, Masssachusetts-based Draper Laboratories , to further this work.
Nanotechnology based on magnetism is increasingly used in vitro to identify and target pathogens. University of California Santa Barbara researchers, for example, creaed a micro-magnetic separation device to improve drug candidate identification. Using a collection of proteins with a different gene inserted, the scientists created a library of billions of phages, each displaying a different protein. When magnetic beads coated with a target molecule are mixed with the phage library, the potential drug candidates bind with the beads and the rest are washed away.
In developing the device to detect Sepsis, researchers noted that there could be a role for the pathologist. When the patient is evaluated, there would be the need to prepare magnetic beads coated with the antigens specific to the suspected pathogens. The pathologist would then evaluate the results of the procedure, advising the care team as to whether the patient was positive for the suspected pathologens, or whether another round of tests for different pathogens may be needed.
Dark Daily notes that these new technologies offer the capability to custom-mix multiple sets of magnetic beads, possibly at the patient’s bedside, That would bring laboratory professionals outside the laboratory and into patient settings. Further, because these magnetic beads are capable of capturing and removing the agents of disease, this could make it feasible for pathologists to have an active role in patient treatment, as they monitor the accuracy of diagnosis and the effectiveness of this nano-technology to remove the infectious agents.
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