Office of Technology Transfer – University of Michigan

New Chemical Indicator of Bacterial Infection having Unique Raman Signature

Technology #4864

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Researchers
Michael D. Morris
Managed By
Janani Ramaswamy
Licensing Specialist, Medical Deviceses 734-763-9081
Patent Protection
US Patent Pending
US Patent Pending

Osteomyelitis is a microbial infection of the bone that can result from an open injury, trauma, or during orthopedic surgery. If left untreated, the infection can spread, become chronic and lead to the death of bone tissue. In severe cases such as osteomyelitis of the diabetic foot, amputation may be needed to stop the infection. Osteomyelitis can be diagnosed through several means: bone biopsy, needle aspiration, needle biopsy, blood tests, X-rays, Magnetic Resonance Imaging, or radionuclide imaging. The blood and tissue sample tests are further processed at a laboratory to detect bacterial infection. All of these methods are relatively invasive and have a low sensitivity requiring the infection to progress to a certain level before it can be detected. Additionally, the imaging scans require advanced scheduling and the results from these procedures as well as laboratory testing can take hours to days to be acquired, therefore allowing the infection to progress. The longer the infection progresses, the more likely it is to spread and cause tissue necrosis. Thus, there is a need for faster and more accurate detection of bacterial infections of the bone. This technology utilizes Raman spectroscopy and light scattering to identify particular calcium phosphate minerals that are indicative of a bacterial infection. These methods require little sample prep and are sensitive to low levels of bacteria, providing a faster method of detecting osteomyelitis.

Brushite used as a chemical indicator for the presence of a bacterial infection identified using a unique Raman Signature

This technology utilizes the detection of calcium phosphate minerals to determine if there is a bacterial infection present. Calcium phosphate minerals are found throughout the human body in both healthy and diseased individuals, most commonly in the form of carbonated apatite. In acidic environments, carbonated apatite dissolves and converts to dicalcium phosphate dehydrate, commonly known as brushite. These acidic environments of a pH of approximately 4.5 occur in bone tissue due to a bacterial infection. Additionally, brushite has a specific and unique Raman signature that makes it easily identifiable using Raman spectroscopy. This technology utilizes this signature by irradiating a bone tissue sample and placing it in growth media that is impregnated with carbonated apatite. If a bacterial infection is present, it will result in the conversion of the carbonated apatite in to brushite, which can then be detected by its Raman signature. Since brushite contains this unique signature, it can be detected in small amounts therefore, allowing a quick and sensitive detection of osteomyelitis that current technologies cannot provide. Early detection of an infection can allow for earlier treatment and better patient outcome.

Applications

  • Diagnosis of bacterial infections
  • Method of determining the condition of bone tissue
  • Apparatus for the detection of brushite

Advantages

  • Faster
  • More sensitive
  • Early detection
  • Unique Raman signature
  • Little sample prep