Microfluidic wet spinning of chitosan-alginate microfibers and encapsulation of HepG2 cells in fibers

The successful encapsulation of human hepatocellular carcinoma (HepG2) cells would greatly assist a broad range of applications in tissue engineering. Due to the harsh conditions during standard chitosan fiber fabrication processes, encapsulation of HepG2 cells in chitosan fibers has been challenging. Here, we describe the successful wet-spinning of chitosan-alginate fibers using a coaxial flow microfluidic chip. We determined the optimal mixing conditions for generating chitosan-alginate fibers, including a 1:5 ratio of 2% (w∕w) water-soluble chitosan (WSC) solution to 2% (w∕w) alginate solution. Ratio including higher than 2% (w∕w) WSC solution increased aggregation throughout the mixture. By suspending cells in the WSC-alginate solution, we successfully fabricated HepG2 cell-laden fibers. The encapsulated HepG2 cells in the chitosan-alginate fibers were more viable than cells encapsulated in pure alginate fibers, suggesting that cross-linked chitosan provides a better environment for HepG2 cells than alginate alone. In addition, we found that the adhesion of HepG2 cells on the chitosan-alginate fiber is much better than that on the alginate fibers.     

On-demand electrostatic droplet charging and sorting

This study reports a droplet-based microfluidic device for on-demand electrostatic droplet charging and sorting. This device combines two independent modules: one is a hydrodynamic flow focusing structure to generate water-in-oil droplets, and the other is the two paired-electrodes for charging and sorting of the droplets. Depending on the polarity on charging electrodes, water-in-oil droplets can be electrostatically charged positively or negatively, followed by automatic real-time electric sorting. This approach will be useful when preformed droplets, with a positive, a negative, or with no charge, need to be manipulated for further on-chip droplet manipulation.     

Bromo-oxidation reaction in enzyme-entrapped alginate hollow microfibers

In this article, the authors present the fabrication of an enzyme-entrapped alginate hollow fiber using a microfluidic device. Further use of enzyme-entrapped alginate hollow fibers as a biocatalytic microchemical reactor for chemical synthesis is also deliberated in this article. To ensure that there is no enzyme leaching from the fiber, fiber surfaces were coated with chitosan. To confine the mobility of reactants and products within the porous hollow fibers the entire fibers were embedded into a transparent polydimethylsiloxane (PDMS) matrix which also works as a support matrix. A vanadium-containing bromoperoxidase enzyme isolated from Corallina confusa was used as a model enzyme to demonstrate the use of these alginate hollow-fiber reactors in bromo-oxidation of phenol red to bromophenol blue at different dye flow rates. Stability of the entrapped enzyme at different temperatures and the effect of the chitosan coating on the reaction conversion were also studied. It was observed that molecules as big as 27 kDa can be retained in the matrix after coating with chitosan while molecules with molecular-weight of around 378 Da can still diffuse in and out of the matrix. The kinetic conversion rate in this microfluidic bioreactor was more than 41-fold faster when compared with the standard test-tube procedure.     

Student learning performance in online collaborative learning

Education and Information Technologies - Online collaborative learning (OCL) has received significant attention, but the ultimate goal of adopting OCL is neglected, especially in higher education...     

The Home Literacy Environment and Preschool Children's Reading Skills and Interest

Research Findings: This study explored the association between the home literacy environment (HLE), conceptualized as comprising parents’ reading beliefs and home literacy practices, and preschoolers’ reading skills and reading interest. It also identified factors in the HLE that predict emerging reading competence and motivation to read. A total of 193 children age 6 years from 14 preschools across Singapore and their parents participated in the study. The parents completed a reading belief inventory, a family literacy activity inventory, and a demographic questionnaire that surveyed the child's reading interest. The children were administered a battery of standardized literacy tests. The study found a moderate relationship between the HLE and children's reading competencies and a strong relationship between the HLE and children's reading interest. When parents’ education level and children's age were controlled, hierarchical multiple regression analyses found that family literacy activities contributed more unique variance to children's reading outcomes and reading interest than did parents’ reading beliefs. Active parental involvement was the strongest component of the HLE, with parent–child engagement in reading and writing emerging as the best predictor of both the child's emerging reading skills and reading interest. With respect to reading beliefs, parents’ efficacy in supporting literacy development before their child attended school positively predicted reading competence, as did parents’ affect and verbal participation in fostering reading interest. However, verbal participation negatively predicted Singapore children's reading competence. Practice or Policy: The implications of the results were discussed.     

Therapeutic radionuclides in nuclear medicine: current and future prospects

The potential use of radionuclides in therapy has been recognized for many decades. A number of radionuclides, such as iodine-131 (¹³¹I), phosphorous-32 (³²P), strontium-90 (⁹⁰Sr), and yttrium-90 (⁹⁰Y), have been used successfully for the treatment of many benign and malignant disorders. Recently, the rapid growth of this branch of nuclear medicine has been stimulated by the introduction of a number of new radionuclides and radiopharmaceuticals for the treatment of metastatic bone pain and neuroendocrine and other malignant or non-malignant tumours. Today, the field of radionuclide therapy is enjoying an exciting phase and is poised for greater growth and development in the coming years. For example, in Asia, the high prevalence of thyroid and liver diseases has prompted many novel developments and clinical trials using targeted radionuclide therapy. This paper reviews the characteristics and clinical applications of the commonly available therapeutic radionuclides, as well as the problems and issues involved in translating novel radionuclides into clinical therapies.     

Rapid and cost-effective fabrication of selectively permeable calcium-alginate microfluidic device using ��modified�� embedded template method

In this paper, we have presented a non-lithographic embedded template method for rapid and cost-effective fabrication of a selectively permeable calcium-alginate (Ca-alginate) based microfluidic device with long serpentine delay channel. To demonstrate the versatility of the presented method, we have demonstrated two different strategies to fabricate serpentine long delay channels without using any sophisticated microfabrication techniques, in formal lab atmosphere. The procedure presented here, also, enables the preparation of a multilayered microfluidic device with channels of varying dimensions, in a single device without using any sophisticated micromachining instrumentation. In addition, we have also qualitatively studied the diffusion of small and large molecules from a Ca-alginate based microfluidic device and proposed a method to effectively control the out-flow of macro biomolecules from the crosslinked Ca-alginate matrix to create a selectively permeable matrix required for various biological and biomimetic applications, as mentioned in the Introduction section of this work.     

Gravity-oriented microfluidic device for uniform and massive cell spheroid formation

We propose a simple method for forming massive and uniform three-dimensional (3-D) cell spheroids in a multi-level structured microfluidic device by gravitational force. The concept of orienting the device vertically has allowed spheroid formation, long-term perfusion, and retrieval of the cultured spheroids by user-friendly standard pipetting. We have successfully formed, perfused, and retrieved uniform, size-controllable, well-conditioned spheroids of human embryonic kidney 293 cells (HEK 293) in the gravity-oriented microfluidic device. We expect the proposed method will be a useful tool to study in-vitro 3-D cell models for the proliferation, differentiation, and metabolism of embryoid bodies or tumours.     

School‐to‐work transition services for students with disabilities in Malaysia: organisations' views on policy and practices

Transition services are required by law for students with disabilities in many developed countries. In Malaysia, however, there is still no specific legislation mandating that school‐to‐work transition planning and services be provided to students with disabilities. This study investigated the state of the transition services provided by educational organisations to students with disabilities in Malaysia. A mixed method research design, which utilises both quantitative and qualitative research techniques, was employed to obtain information from 23 government organisations and NGOs involved in the education and training of students with disabilities. This study found that the organisations surveyed were aware of the lack of transition support and call attention to the importance of instituting a national policy on school‐to‐work transition services and supported employment systems for students with disabilities. The legislative and educational implications for Malaysia are discussed.     

Developing Singapore school leaders to handle complexity in times of uncertainty

In times of uncertainty, university faculties have a duty to prepare school leaders to handle complexity, as the number of variables in the educational system and the interactivity of variables increase exponentially. The Leaders in Education Program (LEP) is a 6-month full-time program at the Singapore National Institute of Education (NIE, which is a part of Nanyang Technological University). The LEP aims to prepare especially selected vice-principals and ministry officers in Singapore for school leadership. The LEP is a collaborative effort between the NIE and the Ministry of Education, an example of a university–government partnership in program development. This article describes the efforts of the LEP in developing the ability of school leaders to deal with complexity. It also examines in detail one particular component of the LEP, the Creative Action Project, to illustrate how this is done in practice, and analyzes the views of participants on their learning through the project.