Rapid, culture-independent, optical diagnostics of centrifugally captured bacteria from urine samples.

Authors:
Katharina Wolf
Katharina Wolf
Knappschaft Eye Clinic Sulzbach
Germany
Wolfgang Pfister
Wolfgang Pfister
University Hospital of Jena
Germany
Dr. Jens Ducree, Dr. rer. nat. habil. Dipl. Phys.
Dr. Jens Ducree, Dr. rer. nat. habil. Dipl. Phys.
Fraunhofer Project Centre at Dublin City University
Professor (Full)
microfluidics, Lab-on-a-Chip, hydrodynanmics, business development, project management, organisational leadership
Glasnevin, Dublin 9 | Ireland

Biomicrofluidics 2015 Jul 11;9(4):044118. Epub 2015 Aug 11.

Biomedical Diagnostics Institute, National Centre of Sensor Research, School of Physical Sciences, Dublin City University , Glasnevin, Dublin 9, Ireland.

This work presents a polymeric centrifugal microfluidic platform for the rapid and sensitive identification of bacteria directly from urine, thus eliminating time-consuming cultivation steps. This "Lab-on-a-Disc" platform utilizes the rotationally induced centrifugal field to efficiently capture bacteria directly from suspension within a glass-polymer hybrid chip. Once trapped in an array of small V-shaped structures, the bacteria are readily available for spectroscopic characterization, such as Raman spectroscopic fingerprinting, providing valuable information on the characteristics of the captured bacteria. Utilising fluorescence microscopy, quantification of the bacterial load has been achieved for concentrations above 2 × 10(-7) cells ml(-1) within a 4 μl sample. As a pilot application, we characterize urine samples from patients with urinary tract infections. Following minimal sample preparation, Raman spectra of the bacteria are recorded following centrifugal capture in stopped-flow sedimentation mode. Utilizing advanced analysis algorithms, including extended multiplicative scattering correction, high-quality Raman spectra of different pathogens, such as Escherichia coli or Enterococcus faecalis, are obtained from the analyzed patient samples. The whole procedure, including sample preparation, requires about 1 h to obtain a valuable result, marking a significant reduction in diagnosis time when compared to the 24 h and more typically required for standard microbiological methods. As this cost-efficient centrifugal cartridge can be operated using low-complexity, widely automated instrumentation, while providing valuable bacterial identification in urine samples in a greatly reduced time-period, our opto-microfluidic Lab-on-a-Disc device demonstrates great potential for next-generation patient diagnostics at the of point-of-care.

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http://dx.doi.org/10.1063/1.4928070DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4537478PMC
July 2015
13 Reads
4 PubMed Central Citations(source)
3.36 Impact Factor

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