The key to effective treatment for bacterial infection, is identifying the infectious bacteria. Anyone who has ever had a rapid test fail, followed by insufficient antibiotics, can attest to the frustration and confusion prolonged suffering will bring. Furthermore, current methods to accurately identify infectious agents take several days and include expensive processes such as culturing, PCR, and antibody identification. To address this issue, we began using fluorescent molecules with the ability to change their fluorescence depending on their environment.
The dyes are derivatives of hydroxyflavanoids which are
naturally found in plants. Aside from producing the colors we see in leaves in
the fall, these molecules have the unique ability to emit three fluorescent
signals, as opposed to two, with the third signal being dependent on its
interaction with the environment. By modifying different moieties on these
dyes, we are able to specify hydrophobic and hydrophilic interactions with the
bacteria themselves, as well as within the microenvironment due to chemicals secreted by the bacteria.
Recognizing these unique properties, we developed an array where we plated samples of known bacteria with polymer complexes of four of these dyes. We then measured the fluorescent signals of these dyes at various points of excitation. Using linear dimensional analysis (LDA), we were able to plot the fluorescent signals we had measured. These plots showed not only specificity for singular samples of bacteria, but in mixed samples the plots showed an association between the specific mixtures we had measured. Along with this, the plots between mixtures showed specificity for the ratio of different bacterial samples in a mixture. The goal of this research is to eventually design an inexpensive assay that can be used in most clinics that will allow for specific identification of samples within a couple of hours as opposed to the current model which requires several days.
Oh, and the analysis turned me in to an excel wizard. Thank you for reading!
This is so fascinating! The clinical utility would significantly decrease time to treatment due to not having to wait long times for culture processing. Even better if they could create a point of care test that you could manually process in a clinic. It would save thousands of man hours by reducing the time and overhead needed to process and store individual cultures, as well as decreasing the number of samples that need to be transported to processing labs.
ReplyDeleteThat is exactly the goal of the study. Another component is to develop a paper based platform using hydrophobic polymers to produce the "wells". This would not only lead to increased interaction of samples with the dyes, but would reduce the overall costs even further since they could be mass produced without the need for plastic based 96-well plates!
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