Research
Bio-imaging and Biomimetic
The optical microscope has played a central role in helping to untangle the complex mysteries of biology ever since the seventeenth century when Dutch inventor Antoni van Leeuwenhoek and English scientist Robert Hooke first reported observations using single-lens and compound microscopes, respectively. However, despite a vast number of technical advances in the last three centuries, a fundamental set resolution-restricting physical laws cannot be easily overcome by rational alternations in objective lens or aperture design. These limitations are often referred to as the diffraction barrier, which restricts the ability of optical instruments to distinguish between two objects separated by a lateral distance less than approximately half the wavelength of light used to image the specimen.
One such resolution enhancing method is laser scanning confocal microscopy, which has been widely used to moderately enhance spatial resolution along both the lateral and axial axes, but the technique remains limited in terms of achieving substantial improvement. The trade-offs in the implementation of this technique severely limit the achievable signal-to-noise ratio, and, as a result, rather than providing dramatic improvements to resolution, the primary advantage of confocal microscopy over traditional widefield techniques is the reduction of background signal originating from emission sources removed from out-of-focus light, which enables crisp optical sections to be obtained for three-dimensional volume-rendered imaging.
Beyond diffraction-limited optical imaging
Our group aims to developed high-resolution lens-less photon-based imaging technique that bypasses the diffraction limit to investigate the mechanism of plant-derived extracellular vesicle (pEV) uptake (see figure below) and antitumor and anti-inflammatory effects in the complex tissue microenvironment. This technique is equally capable of imaging live cells in vivo, in 3D, without compromising its non-invasiveness and biomolecular specificity. Our approach does not rely on labeling or staining of samples, permitting us to apply it to different scientific areas.
Biomimetic
Biomimetic refers to the design and production of materials, structures, and systems that are modeled on biological entities and processes. It is an interdisciplinary field that seeks to emulate nature’s time-tested patterns and strategies in order to solve human challenges. Our group uses biomimetics in various domains, including materials science, fundamental physics, engineering, robotics, and medicine, often resulting in innovative and sustainable solutions. For example, the design of Velcro was inspired by the way burrs stick to animal fur, and self-cleaning surfaces have been developed by studying the properties of lotus leaves.
For decades, humans have mimicked nature for inspiration to create or optimize devices and machines, as well as industrial fabrication, characterization processes and strategies. Besides studying quantized plasma oscillations (plasmons) in metallic nanostructures and at interfaces between metals and dielectrics, we dwell into a branch of science which designs materials and machines inspired in the structure and function of biological systems. Since nature possesses a diversity of photonic structures that have been fine-tuned over millions of years by trial and error; we study a range of bio-inspired features such as structural color vs pigmentary color with the aim of building new photonic devices.
- By utilizing the interaction of structured light (polarization, OAM, frequency, etc.) states with structural features in anisotropic media, a host of devices can be studied
- Tunable refractive index & polarization will give us access to different applications of directional birefringence and dichroism
- Adjustable, constrained, directionally dependent instruments will permit controlled studies of the devices
A Conventional broadband reflection microscope with different angles of illumination (a) is used to image the bright metallic blue colored structures of the Morpho Marcus butterfly wing with illumination from all angles (b) and to show the directional dependency of the reflected light with blue wavelength synthesized in a pseudo-color image (c) where blue channel of the 2pm illumination image is assigned to a blue channel of the synthesized image, blue channel of the 8pm illumination image is assigned to red channel of the synthesized image and blue channel of 5pm illumination image is assigned to the green channel of the synthesized image. This is a direct evidence of structural coloring.
