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Biofilm Inhibition in Oral Pathogens by Nanodiamonds​

Complex microbial communities, e.g., biofilms residing in our oral cavity, have recognized clinical significance, as they are typically the main cause for infections. Diamond nanoparticles, namely, nanodiamonds (NDs) have been demonstrated to work as an effective antibacterial agent against planktonic cells (free-floating state) due to their many promising physico-chemical properties. However, little is known about the behaviors of NDs against biofilms (sessile state).

Tech Talk – Light or Fiber Touch

Precision manipulation of various liquids is essential in many fields, including DNA analysis, proteomics, cell assay and clinical diagnosis, chemical synthesis, and drug discovery. Their divisible, sticky, and sometime infectious features impose, however, great challenges on processing them, particularly when their volume is down to nano-/subnano-liter. A blood droplet from an Ebola patient can for example infect medical workers through the skin. For diagnosis, medial workers have to crash, filter, and purify a patient’s blood sample to obtain the virus’s genetic materials. This series of operations, very often in a fluidic medium, is highly infectious. Moreover, fluids stick to surfaces, which will contaminate containers and handling tools, causing potential dangers if the medical wastes are not properly managed. In this talk, Prof. Wang shall demonstrate how a simple light or fiber touch functions as a “magic” wetting-proof hand to navigate, fuse, pinch, and cleave fluids on demand, being capable of reducing and even replacing the usage of disposable plastics in the biomedical and pharmaceutical industries.

Tech Talk – HINCare: Using Heterogenous Information Networks for Elderly Care Recommendation

In Hong Kong, the number of elderly citizens is estimated to rise to one third of the population, or 2.37 million, in year 2037. As they age and become more frail, the demand for formal support services (e.g., providing domestic or escort services) will increase significantly in the coming years. However, there is a severe lack of manpower to meet these needs. Some elderly-care homes reported a 70% shortage of employees. There is thus a strong need of voluntary or part-time helpers for taking care of elders.
In this talk, Prof. Cheng will introduce HINCare, a software platform that encourages mutual-help and volunteering culture in the community. HINCare uses the HIN (Heterogeneous Information Network) to recommend helpers to elders or other service recipients. The algorithms that use HINs and AI technologies for matching elders and helpers are based on our recent research results. This is the first time that HIN is used to support elderly care.
HINCare is now downloadable in Apple and Google Play Store, and has been serving more than a thousand of elders and helpers in NGOs (e.g., SKH and CSFC). The app is originally designed for elderly users, but has now expanded its services to support the Community Investment and Inclusion Fund (CIIF) and 10 NGOs engaged in teenage and family services. The system won the HKICT Award 2021, Asia Smart App Award 2020, and the HKU Faculty Knowledge Exchange Awards 2021 HKU.

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 – Wastewater-based Epidemiology: A lesson from COVID-19

Infectious diseases are one of the grand challenges to the public health today. The ability to rapidly monitor the spread of diseases in a large scale is the key for prevention, intervention and control of these diseases. Wastewater-Based Epidemiology (WBE) is based on the wastewater of a population, which means the pooled samples from thousands of people, to monitor the disease outbreaks at the community level. In the past two years, COVID-19 sewage surveillance has been applied to provide the early warning signal, to monitor the spread trend of the virus, to uncover the infected persons, and to trace the spread of different variants. In Hong Kong, the sewage surveillance technology developed by the multidisciplinary team of Civil Engineering and Public Health of the University of Hong Kong has been incorporated into the whole control strategy against COVID-19 since December 2020. Currently, the routine sewage surveillance programme of the Hong Kong Government covers more than 150 regular sampling sites in different areas, providing monitoring results for over 5 million people. Similar WBE surveillance systems have also been well-established in many countries, including USA, EU members, Australia, Singapore, etc. In the future, the wastewater surveillance systems are not only helpful in the fight against SARS-CoV-2 but also will be an essential part of the smart city to protect people’s health from known pathogens and unknown emerging new pathogens. In summary, wastewater tells us the health of a city, and we are learning how to listen to it carefully.

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.

Soft Robotic Manipulator for Intra-operative MRI-guided Transoral Laser Microsurgery

Magnetic resonance (MR) imaging (MRI) provides compelling features for the guidance of interventional procedures, including high-contrast soft tissue imaging, detailed visualization of physiological changes, and thermometry. Laser-based tumor ablation stands to benefit greatly from MRI guidance because 3D resection margins alongside thermal distributions can be evaluated in real time to protect critical structures while ensuring adequate resection margins. However, few studies have investigated the use of projection-based lasers like those for transoral laser microsurgery, potentially because dexterous laser steering is required at the ablation site, raising substantial challenges in the confined MRI bore and its strong magnetic field. Here, we propose an MR-safe soft robotic system for MRI-guided transoral laser microsurgery. Owing to its miniature size (Ø12 × 100 mm), inherent compliance, and five degrees of freedom, the soft robot ensures zero electromagnetic interference with MRI and enables safe and dexterous operation within the confined oral and pharyngeal cavities. The laser manipulator is rapidly fabricated with hybrid soft and hard structures and is powered by microvolume (<0.004 milliter) fluid flow to enable laser steering with enhanced stiffness and lowered hysteresis. A learning-based controller accommodates the inherent nonlinear robot actuation, which was validated with laser path-following tests. Submillimeter laser steering accuracy was demonstrated with a mean error < 0.20 mm. MRI compatibility testing demonstrated zero observable image artifacts during robot operation. Ex vivo tissue ablation and a cadaveric head-and-neck trial were carried out under MRI, where we employed MR thermometry to monitor the tissue ablation margin and thermal diffusion intraoperatively.

Anti-COVID-19 stainless steel

Stainless steel (SS) is one of the most extensively used materials in public areas and hygiene facilities but has no inherent antimicrobial properties. Additionally, SARS-CoV-2 exhibits strong stability on regular SS surfaces, with viable viruses detected even after three days. This has created a high possibility of virus transmission among people using these areas and facilities.

Tech Talk – Unravelling the transmission of vertical outbreaks: Each drainage stack is an aerosol factory

More than 10 vertical outbreaks of COVID-19 have been observed in high-rise housing in Hong Kong. Together with the 2003 SARS Amoy Garden outbreak, these outbreaks suggest the roles of building drainage pipes in the transmission of infection, probably not limited to SARS and SARS-CoV-2. In collaboration with the Environmental Protection Department (EPD), we conducted field measurements in some of the infection venues and explore the transmission mechanisms. In this Tech talk, Professor Yuguo Li, Chair Professor of Building Environment, shall demonstrate how his proposed chimney effect explains most of these infections, how the drainage pipe was poorly ventilated, what one can do to protect our family, and what society can do to provide healthy housing.