Biophotonics 

Biophotonics is the science of generating and harnessing light to image, detect and manipulate biological matters. It is multidisciplinary in nature and incorporates many science disciplines such as physics, chemistry, mathematics, biology, and engineering. Our areas of interest include optical bioimaging, fiber-optic sensors for pressure and flow measurements in biological system, and advanced optical tweezers for the micromanipulation of biological specimens.

In the area of optical bioimaging, we are interested in the application of lasers for the diagnosis of diseased tissues. In particular, fluorescence spectroscopy has been used to study diseased tissues, such as plaque in the arteries of the human body. There is also an ongoing research programme with the University of Washington, US, to develop a handheld optical bioassay system, illustrated in Fig. 1, for monitoring biochemicals in biological fluids. Such a device will allow healthcare to be decentralized to the various point-of-care environments, thereby improving the quality of medical care and resulting in cost savings through early diagnosis of medical conditions.

 

Figure 1: Illustration of a point-of-care bioassay system

Fiber-optic biosensors offer several advantages over conventional analytical sensors, such as immunity to electrical interference, ease of miniaturization and potential of higher information content than electrical transducers. Research in fiber-optic biosensors is being pursued in our group to develop sensors for applications in medical diagnosis and health monitoring. Some examples of our work  are fiber-optic pressure sensors for orthopaedic applications and total knee joint replacement surgery (Fig. 2), and continuous cardiac output sensors for the in-vivo monitoring of blood flow. 

 

Figure 2: Fiber Bragg grating embedded into a patella button to perform 

pressure mapping during total knee joint replacement surgery

Laser tweezers, also known as optical traps, uses the gradient force derived from changes in the momentum of light around the waist of a focused continuous-wave laser beam to trap small particles or biological cells. Since the pioneering work of Ashkin et al. (1985), optical tweezers have since been recognised as an important tool for biological micromanipulation. Current applications range from fundamental studies of single cell biochemistry and biophysics to medical applications in blood cell analysis and in vitro fertilization. Advanced optical tweezers that will enable the transfer of optical gradient force, spin angular momentum, and orbital angular momentum is currently being investigated using a double hologram interferometer. This new optical tool allows dual rotation within the laser beam and is much more compact than setups employing conventional techniques. Potential applications include the simultaneous angular deformation of cell structures and force measurements. Figure 3 depicts the rotation of yeast cells with our optical tweezer. 

Figure 3: Manipulating 3-mm yeast cells with an optical tweezer

The Biophotonics group is headed by Dr Ng Beng Koon, and consists of the following staff members:

Please contact Dr Ng Beng Koon (Tel: +65-67906559) for more information about the group and possible collaborations.