Going small is big news in medical research. Scientific researchers are perfecting the use of smaller and smaller devices to perform many of the delicate tasks required to keep humans healthy—technology that is progressing at astonishing rates. Now, the research and the procedures are conducted on an almost unimaginably small level, using nanotechnology.

Nanotechnology is allowing researchers to develop methods that first identify and then attack diseases and toxins in the human body before they can even begin their destruction. The real-time, highly specific diagnoses these methods provide will allow doctors and their patients more time to prevent problems from fully emerging instead of trying to cure established diseases. Pathogens that cannot establish a foothold cannot damage delicate, irreplaceable body systems. That is big news.

Professor Kirill Larin uses a portable time-domain Optical Coherence Tomography system for spectroscopic imaging of quantum dots in tissue.

One biomedical and mechanical engineering collaborative research team at the University of Houston Cullen College of Engineering is currently working on a project to develop a highly sensitive, laser-based system that can detect the presence of specific disease biomarkers. The lead investigator on the project is Kirill Larin, director of the UH Biomedical Optics Laboratory and assistant professor of biomedical and mechanical engineering, who has a particular interest in diagnostic imaging, biosensing and microscopy. Larin is collaborating with Matthew Franchek, chair of the Department of Mechanical Engineering and director of the Biomedical Engineering Program, and Pradeep Sharma, assistant professor of mechanical engineering.

The system relies on the fact that certain diseases produce biological indicators, or biomarkers, that doctors can use to detect the presence and magnitude of disease in the human body. The project team is using laser-based sensing to identify protein biomarkers in human tissue that may identify cancers or bioterrorism agents within a patient’s bloodstream in a matter of moments. Currently, doctors and their anxious patients wait up to 24 hours to evaluate cancer blood tests. While this technology will initially rely on drawing blood samples from patients, Larin envisions an in vivo (totally inside the body) system to determine the presence or absence of very specific elements in the blood immediately.

The system falls under the field of Biomedical Optics, a fast-growing area of research in medicine. This particular optical method of diagnostic and functional imaging, detection, and manipulation of cells and tissues draws from the expertise of many disciplines. From the engineering side of the collaboration, the laser-based sensing technology works with specially tailored quantum dots, tiny crystals that glow when stimulated by light. The dots emit various light signals from which the researchers can determine the presence of different agents in a blood sample. Once the laser illuminates the dots, a computer generates something similar to a topographical map, indicating the locations of various quantum dots by sets of peaks. Quantum dots that bind to pathogens will emit a different signal than quantum dots that are unattached, allowing researchers to know whether a pathogen exists.

Generally speaking, the quantum dots are conjugated, or coupled with specific substances, to look for specific pathogens. If one of these pathogens is present, then the researchers will be able to tell based on the shape of the emission signal. These dots, which tell the researchers so much about the disease, are usually between 5 – 10 nanometers in width. In comparison, one human hair is about 80,000 nanometers in width (hair is considered huge in the nano world).

Quantum dots are critical to this study because the researchers can conjugate the dots with specific antibodies that bind with certain proteins, such as a particular type of cancer. Sharma studies quantum dots, and his role on this project is to make theoretical predictions about what specific antibodies need to be conjugated to which quantum dots to determine the presence of specific cancerous agents or other biomedical problems.

“The crucial part Professor Sharma plays in this research is being able to identify proteins and physical/chemical properties of quantum dots that match up specifically,” said Larin.

Franchek’s role will be to calibrate and verify theoretical models developed by Sharma through the use of an atomic force microscope. Franchek will analyze the electrical and mechanical structure of the interaction of Sharma’s predicted connections between the quantum dots and the proteins. Researchers will determine the next step necessary on a case-by-case basis depending on how strong the signal is from the quantum dots. Franchek and Sharma will amass a body of data that will allow doctors to diagnose accurately from the various signals that are identified in this initial research.

Once researchers document which proteins bind with which specially conjugated quantum dot, they can use those quantum dots to look for that protein in biological samples.

In such a system, a patient’s blood sample will be taken and mixed with the quantum dots. The dots would then bind to any present cancerous protein biomarkers. Then, the patient’s blood sample would be inserted into the laser-based sensing system, at which time, the quantum dots would illuminate and emit one signal if they had adhered to a cancerous protein and emit a different signal if they did not find a cancerous protein. By evaluating the signals, researchers would know instantly if the cancer is present. The result would be less waiting, less anxiety and less delay when time is of the essence as it is in cancer detection.

The research team is confident that the combination of nanotechnology and engineering for biomedical research will result in faster and more reliable test results for doctors and patients trying to determine the next steps of keeping the human body working at its peak.

“This is our way to help people live longer and happier lives,” said Larin. “It’s great to be a part of that.”

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