Soft tubular microfluidics for 2D and 3D applications

Microfluidics has been the key component for many applications, including biomedical devices, chemical processors, microactuators, and even wearable devices. This technology relies on soft lithography fabrication which requires cleanroom facilities. Although popular, this method is expensive and labor-intensive. Furthermore, current conventional microfluidic chips precludes reconfiguration, making reiterations in design very time-consuming and costly. To address these intrinsic drawbacks of microfabrication, we present an alternative solution for the rapid prototyping of microfluidic elements such as microtubes, valves, and pumps. In addition, we demonstrate how microtubes with channels of various lengths and cross-sections can be attached modularly into 2D and 3D microfluidic systems for functional applications. We introduce a facile method of fabricating elastomeric microtubes as the basic building blocks for microfluidic devices. These microtubes are transparent, biocompatible, highly deformable, and customizable to various sizes and cross-sectional geometries. By configuring the microtubes into deterministic geometry, we enable rapid, low-cost formation of microfluidic assemblies without compromising their precision and functionality. We demonstrate configurable 2D and 3D microfluidic systems for applications in different domains. These include microparticle sorting, microdroplet generation, biocatalytic micromotor, triboelectric sensor, and even wearable sensing. Our approach, termed soft tubular microfluidics, provides a simple, cheaper, and faster solution for users lacking proficiency and access to cleanroom facilities to design and rapidly construct microfluidic devices for their various applications and needs. Keywords: flexible microfluidics, elastomeric microtubes, microfluidic assemblies, inertial focusing chip, microfluidic sensorSingapore-MIT Alliance for Research and Technology (SMART

Isolation and Characterization of Antibiotic Resistant Bacteria from Swiftlet Feces in Swiftlet Farm Houses in Sarawak, Malaysia

There is a growing concern on the occurrence of antimicrobial resistance. Development of multiple antibiotic resistant bacteria has overtaken new drug development and threatened the patients with untreatable infections. This study was conducted to isolate and characterize the antibiotic resistant bacteria from swiftlet farm houses located in various places including Kota Samarahan, Semarang, Saratok, Betong, Sarikei, Sibu, Sepinang, Maludam, Miri, and Kuching inSarawak, Malaysia.Five fecessamples were collected randomly from each site. One gram of the fecessample was diluted in 9 mLof 0.85% normalsaline solution. The diluted sample was plated on TrypticaseSoy agar plates and incubated at 37±1 °C for 24 h. A total of 500 bacteria isolates were then identified using 16S rRNA analysis method. Disc diffusion method was then used to confirm the resistant phenotypes of these isolates. The results showed that the means of the bacterial colony count were significantly -1 different (p<0.05) from one another, with the highestlog CFU g (9.22±0.72) found in KotaSamarahan and the 10 -1 lowest log CFU g (6.03±0.62) in Betong. Besides, the isolated bacteria were identified as 96% Gram positive 10 bacteria and 4% Gram negative bacteria. The isolated bacteria were highly resistant to penicillin G (36.80±23.87%), ampicillin (28.60±17.13%), and rifampicin (16.90±13.70%). Thus, swiftlet feces are good reservoirfor a range of antibiotic resistant bacteria whichmay pose a potential health hazard to human

A microfluidic-FCS platform for investigation on the dissociation of Sp1-DNA complex by doxorubicin

The transcription factor (TF) Sp1 is a well-known RNA polymerase II transcription activator that binds to GC-rich recognition sites in a number of essential cellular and viral promoters. In addition, direct interference of Sp1 binding to DNA cognate sites using DNA-interacting compounds may provide promising therapies for suppression of cancer progression and viral replication. In this study, we present a rapid, sensitive and cost-effective evaluation of a GC intercalative drug, doxorubicin (DOX), in dissociating the Sp1–DNA complex using fluorescence correlation spectroscopy (FCS) in a microfluidic system. FCS allows assay miniaturization without compromising sensitivity, making it an ideal analytical method for integration of binding assays into high-throughput, microfluidic platforms. A polydimethylsiloxane (PDMS)-based microfluidic chip with a mixing network is used to achieve specific drug concentrations for drug titration experiments. Using FCS measurements, the IC(50) of DOX on the dissociation of Sp1–DNA complex is estimated to be 0.55 μM, which is comparable to that measured by the electrophoretic mobility shift assay (EMSA). However, completion of one drug titration experiment on the proposed microfluidic-FCS platform is accomplished using only picograms of protein and DNA samples and less than 1 h total assay time, demonstrating vast improvements over traditional ensemble techniques

Injectable chemokine-releasing gelatin matrices for enhancing endogenous regenerative responses in the injured rat brain

Thesis: Ph. D., Harvard-MIT Program in Health Sciences and Technology, 2014.Cataloged from PDF version of thesis.Includes bibliographical references.Brain injuries acquired from hemorrhage, ischemic strokes and trauma affect millions worldwide each year and often cause irreversible loss of neural tissue that disrupts vital neurological functions. Cell transplantation has traditionally been the strategy for achieving neuroregeneration but endogenous regenerative responses such as neurogenesis and neovascularization are increasingly recognized as an elegant alternative. These responses are directed toward injured tissues via chemokine signaling such as the stromal cell-derived factor-I a (SDF-1 [alpha])/CXCR4 pathway and offer the potential to replace lost neurovascular elements. Endogenous regenerative responses are, however, not fully effective in the injured brain. Two prominent barriers are the loss of chemokine expression and disappearance of stroma following tissue loss in the brain lesion, which lead to sub-optimal engagement of endogenous regenerative responses and inability of recruited cells to infiltrate the lesion. The overall goal of this thesis was therefore to develop an injectable lesion-filling matrix that could re-establish chemokine release and stroma, thereby enhancing endogenous regenerative responses. Toward this goal, we demonstrated injectable gelatin-hydroxylphenylpropionic acid (Gtn-HPA) hydrogels as an appropriate scaffolding material that was permissive for proliferation, migration and differentiation of adult neural progenitor cells (aNPCs). We also synthesized dextran sulfate/chitosan polyelectrolyte complex nanoparticles (PCN), which could encapsulate SDF-1[alpha] efficiently and sustain its release for 4 weeks. When used in an in vitro migration assay to fill a core region that was surrounded by an aNPC-laden hydrogel construct, the resulting Gtn-HPA/SDF- 1[alpha]-PCN matrix recruited aNPCs to accumulate around and migrate into the core region. When injected into the brain lesion in a rat model of intracerebral hemorrhage, Gtn-HPA/SDF-1[alpha]-PCN matrix successfully increased the migration of endogenous neuronal precursors into the injured striatum and amplified neovascularization. Gtn-HPA/SDF-l[alpha]-PCN matrix also led to a newly formed vasculature within the lesion and supported infiltration by endogenous cells that included neutrophils expressing CXCR4 and VEGF. The neutrophil infiltrate did not spread to surrounding tissue or induce necrosis and compelled further investigation for their role in the injured brain. Importantly, Gtn-HPA/SDF-l[alpha]-PCN matrix reduced brain tissue loss and improved behavioral recovery. Overall, Gtn-HPA/SDF-l[alpha]-PCN matrix offered an opportunity to enhance endogenous regenerative responses and confer benefits to the injured rat brain.by Teck Chuan Lim.Ph. D

Hardware : efficient techniques for FAST corner detector

Corner detector is the foundation to many computer vision applications such as high-speed object recognition or object analysis. These applications are beginning to find their way in battery-operated devices such as smart-phones, drones, mobile robots, etc. The corner detection algorithm for these applications must therefore meet real time constraints while ensuring low power consumption. Software implementation on embedded platforms often fails to simultaneously meet these conflicting requirements. For example, low end embedded microcontrollers consume less power but are slow. On the other hand, high end processor consumes higher power to achieve high speed. In order to meet the real-time and low power requirements, some well-known hardware acceleration methods for corner detection algorithm such as FAST, Shi - Tomasi, SUSAN and Harris have been presented in the literature. In this paper, the focus will be on hardware implementation for the FAST corner detector which has been reported to have the lowest execution time. In this thesis, six hardware designs have been proposed for the FAST corner detection architecture. These hardware designs aim to reduce the resources, computation time and power dissipation. The unrolled hardware design is proposed to eliminate the usage of a 7x7 convolution buffer in the baseline architecture to reduce the resources utilized by 5.3%. The merged hardware design provides resource sharing of the scoring units in the unrolled implementation by utilizing multi-pumping [18]. Subsequently, another hardware design, Two’s Complement Merged (TCM) was proposed to remove the redundant multiplexors used by introducing a 2's complement operation at the end of the computation. With these optimizations, the total resources were reduced further by 27%. Eventually, a simpler design (XNOR TCM) was proposed to introduce the XNOR logic to simplify the complex pixel scoring module in the TCM approach. The simplification of the design reduced the number of switching activities which in turns reduce dynamic power dissipation by 47.5% when compared to the baseline architecture. To reduce the computation time, the delayed TCM employed pipelining in the critical path. This approach exploited the resource utilization achieved in previous designs. It led to a reduction in total thermal power dissipation by 18.5%, and total resource usage dropped by 14.9% while the difference in minimum period was only 6.3% difference compared to baseline architecture. Finally, the heuristics design was proposed to reduce the resources utilized in the non-maximal suppression module by introducing three scoring units. These hardware designs were implemented and demonstrated on the TERASIC DE2i-150 FPGA development kit.Bachelor of Engineering (Computer Engineering

ADVANCES IN TECHNOLOGIES FOR PURIFICATION AND ENRICHMENT OF EXTRACELLULAR VESICLES.

10.1177/2472630319846877SLAS Technol2472630319846877

Competitiveness of the banking industry in Singapore.

The local banking sector is currently under major revamps. Our FYP attempts to look at these revamps that are taking place and we try to evaluate the rationals and the effects of these revamps

Market research : CanDia5

To undertake the role of market research consultants for Rockeby biomed Ltd to test the market feasibility of Candia5 in the local market, and investigate possible problems of introducing Candia5