Biomedical Engineering

TechTalk – A “Programmable” Cell Niche Engineering Platform – Multiphoton Microfabrication and Micropatterning (MMM) Technology

In native tissues, cells reside in a complex microenvironment (niche) consisting of factors including neighbor cells, soluble factors, extracellular matrices, topological and mechanical signals. Cell niche is critical in maintaining their phenotype and determining their fates and functions. Reconstituting complex cell niche factors in vitro, either individually or in combinations, in a quantitatively and spatially controllable manner, is critical for investigating the interactions between cells and their niches and hence deriving designing strategies for optimal conditions during cell culture applications and optimal scaffolds for tissue engineering applications. Our lab has developed a multiphoton microfabrication and micropatterning (MMM) technology. Here, the technical capability of the MMM platform in fabricating complex protein microstructures and micropatterns with pre-designed topological features, mechanical properties, extracellular matrix, cell interaction molecules and soluble factors, and biomedical applications including cell niche factor screening for phenotype maintenance and engineering cell niche for cell fate determination will be discussed.

Tech Talk – Seeing the unseen in biomedicine with laser

In the past 10+ years, laser microscopy has successfully made it permeated not only in biochemistry and cell/molecular biology research, but also in numerous preclinical and clinical applications. However, our understanding of health and disease is still very limited. This lecture will introduce the latest breakthrough in laser microscopy technologies developed at HKU that can address some of these challenges. Especially these technologies can generate unprecedented views and understanding of the living biological cells. They include: capturing high-resolution motion picture of the swift-flying brain signals in a living animal; visualizing the inner workings of biological cells and organisms in 3D without killing them; and detecting rare cancer cells in millions of blood cells. Not only can these technologies impact new biological discovery (e.g. neuroscience), but also creating many new opportunities in cost-effective clinical diagnosis, especially cancer screening.

Tech Talk – The infini love diamond with a massive future in science

The diamond has been well known as the gem stones in jewellery market, and the same material with various atomic defects, i.e., fluorescent impurities in diamond lattice, shows unique quantum behaviors even at ambient conditions. A diamond, not just a best friend of ladies, but also the best friend of scientists. Due to their unique quantum properties, these atomic defects has been demonstrated to achieve nanometric measurement of various physical quantities such as electromagnetic fields, temperature and etc. with unprecedented precision. Here, I will firstly review the development of diamond-based science and technology, and discuss its potential applications in diverse fields. Specifically, I will introduce the on-going research activities in my group, mainly including the high figure-of-merit diamond materials synthesis, advanced quantum diamond microscope development and diamond quantum sensing in single living cells. In addition, I will also share my journey in exploring beyond academics, e.g., we apply quantum diamond microscope for authenticity identification in local jewellery industry.

Tech Talk – Smarter, smaller and softer robots for medical image-guided minimally invasive surgery

In recent years, there has been a trend towards integrating small, soft and deformable structures into surgical robot systems. Target applications include endoscopy or magnetic resonance imaging (MRI)-guided intervention, where researchers take advantage of soft and flexible robots for their inherent mechanical compliance. However, these flexible robotic systems are often controlled in an open loop or with positional feedback from 3D tracking devices. Not only the real-time feedback of flexible/soft robot configuration or morphology itself is of importance, but also the robot manipulation modelling, as well as its intelligent control, become an area of interest in the field. To this end, this talk will present various robot prototypes, which attempt to resolve unmet clinical and technical challenges for image-guided intervention or surgery, either in strong magnetic field (1.5-3T) by magnetic resonance imaging (MRI) scanner or in confined anatomical space through endoscopy. Machine intelligent approaches, and also the recent advances in continuum robot design and learning-based sensing/control will also be overviewed. These robots have to incorporate with efficient mechanical transmission, thus enabling delicate mechanical force/motion transmitted from actuators to surgical tools in a long and flexible route. The ultimate goal is to provide high-performance control of robotics instruments for safe, precise and effective surgical manipulation. The speaker will not only share his research outcome, but also various difficulties in his up-and-down research journey, from R&D in university, (pre-)clinical trials in hospital, then technology transfer for clinical applications.

Tech Talk – Plastic Response of Cells: from Embryo Development to Disease Detection

Living cells need to undergo significant shape changes during processes such as cell division, migration and tissue formation. Therefore, it is commonly believed that the deformability of cells is intimately related to their capability in executing different biological duties as well as the progression of diseases. In this talk, I will discuss how irreversible deformation of cells ensures proper axial extension of embryos during their development and how the plastic response of tumor cells can be used in monitoring the progression of cancer. Specifically, I will show that the presence of active intracellular/intercellular contraction will trigger the severing and re-bundling of actin filaments in cells (leading to cellular anisotropy and plasticity), elevate the internal hydrostatic pressure of embryo and eventually drive its elongation. In particular, the gradual re-alignment of F-actins must be synchronized with the development of intracellular forces for the embryo to elongate, which is then further sustained by muscle contraction-triggered plastic deformation of cells. In addition, I will also introduce a microfluidic setup developed in our lab allowing us to impose precisely controlled cyclic deformation on cells and therefore probe their plastic characteristics. Interestingly, we found that significant plastic strain can accumulate rapidly in highly invasive cancer cell lines and circulating tumor cells (CTCs) from late-stage lung cancer patients with a characteristic time of a few seconds. In comparison, very little irreversible deformation was observed in the less invasive cell lines and CTCs from early-stage lung cancer patients, highlighting the potential of using the plastic response of cells as a novel marker in future cancer prognosis and monitoring.