Table of Contents

Current Research Projects

Multiplexed Confocal Fluorescence Lifetime Imaging Microscopy

Comparing with conventional wide-field imaging microscopes, confocal microscopy hold significant advantages in image contrast enhancement, 3D sectioning capabilities, and compatibility with specialized detectors. For applications such as live cell imaging, slow acquisition speed is a key barrier to adaption of confocal microscopy. While wide-field microscopy is typically faster, multiplexed confocal schemes such as using a spinning foci array can significantly increase the image acquisition rate. The moving foci array in the spinning disc, however, prevents the use of specialized discrete photo detectors arrays.

We have developed a suite of technologies to generate, scan, and measure 1000+ confocal foci simultaneously, while is compatible with stationary discrete detectors. Another key feature of the technique is that it can be retrofitted to a conventional wide-field fluorescence microscope. We are also developing various related technologies for its applications in drug discovery and in vivo imaging.
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Ultrafast lasers in surgical applications and advanced manufacturing of biomedical devices

Microstructure materials are currently used in different fields. One of these areas is sensor devices such as microfluidic devices. The devices are made from transparent materials such as glass and PDMS (Polydimethylsiloxane). There are several techniques that are currently used to remove substance and create microchannels on material surface, laser ablation is one of the important methods that can be used in microfabrication. This importance results from the development of laser. In the past, laser with long pulse duration (>picosecond) had been used to fabricate microstructure materials, but because pulse duration of laser was longer than thermal relaxation time of ablated material, the thermal effect was present and caused micro crackers into materials. However, after ultrafast pulse laser (pulse duration <picosecond) is generated, the micro processing of materials using this laser allows for the possibility of material removal on order of micro scale with low thermal damage. In fact, manufacture of microstructure materials using ultrafast pulse laser is still under study.

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Imaging in the Gastrointestinal Tract ("Google Streetview" of the Colon)

In colonoscopy, it is important to monitor the progression or recurrence of suspected cancerous lesions (e.g., polyps). Because the colon is contractile and mobile, however, it is very difficult to relocate a lesion (e.g., a polyp) even during the same procedure. We are developing a novel 360 degree panoramic imaging method to build a map of colon lining, during colonoscopy, and use it to locate and track cancerous and pre-cancerous lesions. This research will make colon cancer screening and treatments more effective.

A motion tracking device was previously developed to provide the accurate position, rotation, and velocity of the endoscope to be used in both upper and lower gastrointestinal procedures. It will help gastroenterologists during examination, diagnosis, treatments, and follow-ups to record precise location information during a procedure whether it is for determining the exact area for follow-ups, training doctors, or comparing the size of a tumour. In the current phase, this prototype design is being optimized using modern camera and imaging features as well as hardware and software design to produce a more efficient product that can be used in a clinical setting. The benefits of this design as compared to other solutions are the cost-effective, small-sized, real-time, and software based approach that can simplify the design and minimize the weight of the device. It is also placed externally on the endoscope and does not go inside the patient which allows for it to be removed or disposed.


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Micro and Nano-Biosensing/Imaging Devices

Conventional optical spectroscopy and imaging systems are large, complex and costly optoelectronic instruments comprised of lasers, spectrophotometers, and detectors. Often, their size is the limiting factor for their use in certain applications such as in-situ monitoring of physiological processes and distributed environmental sensing. In practice, there are strong demands for miniaturized, integrated devices for biomedical applications.

Recent advances in micro-photonics and electronic devices have led to small but efficient components/modules. These technologies are mostly built upon well-established microelectronic technologies for integrated circuitry. When conventional devices are replaced with micro-components, new applications and capabilities can be facilitated. Moreover, it usually leads to significant cost reductions and increases in yield associated with mass production.

The overall objectives of this project area include (i) develop novel micro-optical sensing and imaging device technology with spectrally- and temporally-resolved optical signal acquisition; (ii) investigate the integration and packaging of complete sensing/imaging devices; and (iii) study the applications of such devices in biomedical and environmental applications. The proposed program will be based on the Micro/Nano Systems Lab and focus on integrated device technology development. Its success will allow translation of such technology to applications in biomedical diagnosis, drug discovery, and environmental monitoring.


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Hyperspectral Imaging of Skin Erythema for Individualized Radiotherapy


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Smart Aging

We aim to develop wearable and ambient sensing device technologies and personalized AI/ML algorithms for continuous, longitudinal assessment of older adults' health conditions during their daily living activities (ADL). Such longitudinal health dataset will enable early detection and personalized management of chronic and neurodegenerative diseases.

Smart IPS Study
McMaster Smart Home for Aging-in-PlacE

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Optical Biopsy based on time-resolved fluorescence and diffuse reflectance spectroscopy

Time resolved fluorescence (TRF) spectroscopy and diffuse reflectance (DR) spectroscopy have been used as minimally-invasive optical biopsy modalities. They offer real-time alternatives to invasive tissue biopsies. Fluorescence lifetime is independent of intensity variations and adds an additional source of contrast compared to steady state fluorescence. Diffuse reflectance allows for quantitative measurement of optical properties of tissue. Combining both DR and TRF modalities in one optical biopsy instrument allows for the integration of diffuse reflectance, time-resolved, and steady-state spectra for tissue diagnosis as well as real-time correction of the fluorescence lifetime and spectrum based on optical property measurements in-situ.
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Applications of Fluorescence Lifetime Imaging

Barrett’s esophagus (BE) is a precancerous disease with the potential to become esophageal adenocarcinoma, a malignant cancer with a five year survival rate of 12%. Early detection and treatment of BE is crucial to the survival of the patient; however, current detection techniques can be erroneous and slow. A more favourable method of treatment is a real time seek-and-treat strategy at the cellular level through the use of photodynamic therapy. 5-Aminolevulenic acid (5-ALA) has previously been tested as a contrast agent to highlight features at a single cell level. In addition to this, machine learning can be used to extract these highlighted morphological and textural features of the cells to more accurately target specific cells. This procedure has the potential to alleviate cost and discomfort to the patient in comparison to the current biopsy and histology treatment as there is no need to remove samples from the patient. We are working to enhance the detection of BE and implement confocal microendoscopy as a medium for treatment. In order to do this, we use fluorescence imaging of an in vitro model of BE as well as image processing and tools for classification to properly detect and classify the cells. We iteratively test the classification software to ensure sensitive and specific identification for treatment. Our results determined that the algorithm is quick and both highly sensitive and specific at classifying multiple datasets. This is a promising outcome as it is a step toward the implementation of microendoscopy. The speed and accuracy of the algorithm indicates a feasible system. Photodynamic therapy with the help of machine learning is a promising route for cancer prevention.

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Photoacoustic Tomography for Breast Cancer Detection

The goal of the project is to develop a breast imager that can generate functional tomograms of neoplasms like MRI, but with the speed and convenience of mammography and without the painful breast compression , risky X-ray radiations or radioactive infusions. This can be achieved by using photoacoustics.