Data mining in biomedicine : current applications and further directions for research

Author name used in this manuscript: S. K. KwokAuthor name used in this manuscript: A. H. C. Tsang2009-2010 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Engineering drug delivery vehicles with multiphase microfluidics

Track 4: Manufacturing and Materials for Nanomedicine, Biology and Na … - Session: 4-4 Delivery Applications using Polymersomes, Capsules, and Bubbles: paper no. NEMB2013-93028Successful therapies often require the use of drugs, which should be delivered to the target and be released for a certain period of time. To achieve targeted release with a suitable drug release profile, the drug delivery vehicles that first encapsulate and subsequently release the drugs need to be tailored. Conventional drug delivery vehicles, such as polymer microspheres, enable the tuning of the drug release profiles by varying their size, size distribution, as well as the degradation rates of the microspheres. However, more complex release profiles, such as zeroth order release, cannot be easily achieved with polymer microspheres. Moreover, important current approaches to prepare these polymer microspheres are often emulsion-based; they typically involve the use of organic solvents, which may lead to degradation of the drugs involved. Furthermore, certain therapies require the use of a cocktail of multiple drugs, which can include both hydrophilic and hydrophobic drugs. Co-encapsulation and sequential release of hydrophilic and hydrophobic drugs are challenging to achieve with existing drug delivery vehicles. Therefore, novel approaches to fabricate delivery vehicles for encapsulating both hydrophilic and hydrophobic drugs, with complicated drug release kinetics, without the use of organic solvents, are desired. In our work, we propose the use of multiphase microfluidics to prepare drug delivery vehicles with complex structures, such as core-shell capsules, multicompartment microspheres and nonspherical particles; by tailoring the spatial distribution of drugs, unconventional drug release profiles can be achieved. To avoid the use of harmful organic solvents, we introduce the use of aqueous two-phase systems in microfluidics to generate the emulsion templates for making these novel delivery vehicles. By manipulating the interfacial characteristics of the emulsion templates, complex structures with hydrophilic and hydrophobic compartments can be prepared for separate encapsulation and sequential release of both hydrophilic and hydrophobic drugs. We will discuss the fundamental problems that need to be addressed to generate these drug delivery vehicles and highlight their potential by demonstrating their release characteristics.link_to_OA_fulltex

A high throughput approach for discovery of catalytic nucleic acids

Poster Presentation: no. P4Enzymes are biologic polymers. Catalytic nucleic acids are extremely useful and hence there is constant need for improving and discovering of catalytic molecules for industrial, medical and biotechnological applications. In vitro evolution has established that single-stranded nucleic acids can display substrate dependent catalysis of specific biochemical reactions. These single stranded oligonucleotides are called aptamers. Mass production and qualitative detection of single-stranded deoxyribonucleic acids are essential for each round of successful in vitro evolutionary pathways for high affinity binding or catalytic aptamers. In this work we optimized the asymmetric polymerase chain reaction protocol for mass production and subsequently developed a new assay system for detection and quantification of single-stranded deoxyribonucleic acid on the native TBE gel. Further enzyme assay of asymmetric polymerase chain reaction product reflect the quality of single-stranded nucleic acids present in the bulk reaction. We would further translate the ePCR approach into the most powerful ultrahigh-throughput inexpensive droplet-based microfluidics system for discovery of new catalytic nucleic acid variants having stronger catalytic activity. Isolate variants can further be used in diagnostic assay upon modification of nucleotides for resistance to enzymatic and chemical degradation

Prevalence of ocular abnormalities in adults with Down syndrome in Hong Kong

Background/Aims: This was a cross-sectional survey to find the prevalence of visual impairment and eye diseases among adults with Down syndrome (DS) in Hong Kong. Methods: 91 DS patients over the age of 30 were recruited through the Hong Kong Down Syndrome Association. Each patient was provided with a complete ophthalmological assessment including best corrected visual acuity, refraction, slit lamp and fundus examination. Results: In our sample, 56.6% had normal vision to mild vision impairment, 33.7% and 7.2% had moderate and severe vision impairment, respectively, and 2.4% were blind. The mean presenting distant LogMAR visual acuity was 0.66 (Snellen equivalent 20/90), and the best corrected LogMAR visual acuity was 0.48 (Snellen equivalent 20/60). Significant refractive errors were found in 86.3% of the eyes, with spherical equivalent corrections ranging from -23.25D to +3.00D. Myopia and astigmatism were prevalent and found in 59.3% and 72.7% of the eyes, respectively. Blepharitis and chalazion were found in 44% of the eyes, while corneal problems were present in 27.5%. There were low incidences of infective keratitis (0.5%), keratoconus (0.5%) and Brushfield spots (1.1%). Cataracts were found in 72.2% of the eyes; 26.1% were congenital and 44.9% were age-related. Fundal abnormalities were present in 49.5% of the eyes. Conclusions: There is a high prevalence of vision impairment among Chinese DS adults. Uncorrected refractive errors, high myopia and cataracts are the main visually debilitating ophthalmological abnormalities. Vision may be improved through the simple use of glasses and early treatment of age-related cataracts.link_to_subscribed_fulltex

Quantitative asymmetric-detection time-stretch optical microscopy (Q-ATOM) for ultrafast quantitative phase imaging flow cytometry

Biomedical Spectroscopy, Microscopy, and Imaging: 9720 - High-Speed Biomedical Imaging and Spectroscopy: Toward Big Data Instrumentation and Management: Paper 9720-33Based on the interferometric or holographic approaches, recent QPM techniques provide quantitative-phase information, e.g cell volume, dry mass and optical scattering properties for label-free cellular physical phenotyping. These approaches generally rely on iterative phase-retrieval algorithms to obtain quantitative-phase information, which are computationally intensive. Moreover, current QPM techniques can only offer limited image acquisition rate by using CMOS/CCD image sensors, these two limitations hinder QPM for high-throughput quantitative image-based single-cell analysis in real-time. To this end, we demonstrate an interferometry-free quantitative phase microscopy developed on a new generation of time-stretch microscopy, asymmetric-detection time-stretch optical microscopy (ATOM), which is coined quantitative ATOM (Q-ATOM) - featuring an unprecedented cell measurement throughput together with the assorted intrinsic optical phenotypes (e.g. angular light scattering profile) and the derived physical properties of the cells (e.g. cell size, dry mass density etc.). Based on a similar concept to Schlieren imaging, Q-ATOM retrieves quantitative-phase information through multiple off-axis light-beam detection at a line-scan rate of >10 MHz - a speed unachievable by any existing QPM techniques. Phase retrieval in Q-ATOM relies on a non-iterative method, significantly reducing the computational complexity of the technique. It is a particularly important feature which facilitates real-time continuous label-free single-cell analysis in Q-ATOM. With the use of a non-interferometric configuration, we demonstrate ultrafast Q-ATOM of mouse chondrocytes and hypertrophic chondrocytes in ultrafast microfluidic flow with sub-cellular resolution at an imaging throughput equivalent to ~100,000 cells/sec without image blur. This technique shows a great potential for ultrahigh throughput label-free image-based single-cell biophysical phentotyping.The 2016 SPIE Photonics West Conference, San Francisco, CA., 13-18 February 2016. In Conference Proceedings, 2016, v. 9720, paper no. 9720-3