Showing papers by "Lifeng Kang published in 2012"

Iron Oxide Filled Magnetic Carbon Nanotube–Enzyme Conjugates for Recycling of Amyloglucosidase: Toward Useful Applications in Biofuel Production Process

Abstract: Biofuels are fast advancing as a new research area to provide alternative sources of sustainable and clean energy. Recent advances in nanotechnology have sought to improve the efficiency of biofuel production, enhancing energy security. In this study, we have incorporated iron oxide nanoparticles into single-walled carbon nanotubes (SWCNTs) to produce magnetic single-walled carbon nanotubes (mSWCNTs). Our objective is to bridge both nanotechnology and biofuel production by immobilizing the enzyme, Amyloglucosidase (AMG), onto mSWCNTs using physical adsorption and covalent immobilization, with the aim of recycling the immobilized enzyme, toward useful applications in biofuel production processes. We have demonstrated that the enzyme retains a certain percentage of its catalytic efficiency (up to 40%) in starch prototype biomass hydrolysis when used repeatedly (up to ten cycles) after immobilization on mSWCNTs, since the nanotubes can be easily separated from the reaction mixture using a simple magnet. The ...

Protein encapsulation in polymeric microneedles by photolithography

Abstract: Transdermal delivery of protein drugs is a useful alternative to oral and parenteral routes because it circumvents the problems associated with these conventional modes of drug delivery. One such strategy to overcome the natural skin barrier involves encapsulating them inside a polymeric core, offering the advantage of a higher drug loading in one convenient formulation rather than having multiple ones. However, previously reported fabrication approaches required high temperatures, vacuum, or prolonged exposure to ultraviolet light which may be potentially harmful to protein drugs. In this chapter, we described a novel photolithography-based method utilizing low exposure to ultraviolet light developed in the previous chapter to encapsulate bovine serum albumin (BSA) – a model protein for our study. As a proof of concept, this simple photolithographic technique has shown uniform drug distribution across the microneedle arrays, maintained protein stability and shown greater permeation of BSA through the skin as compared to passive diffusion, thereby demonstrating its potential to be used to encapsulate other protein drugs in the future.

Polycaprolactone scaffold as targeted drug delivery system and cell attachment scaffold for postsurgical care of limb salvage

Abstract: In this paper, a dual-function drug-laden polycaprolactone scaffold, which can serve as both targeted drug delivery system and attachment platform for tissue regeneration for the postsurgical care of limb salvage procedure, was developed with a simple and solvent-free molding technique. Scaffolds of varying surface architecture were created using poly(ethylene glycol) diacrylate microneedle arrays. A model drug, rhodamine B, was incorporated homogenously into the scaffold. In vitro drug release studies showed that rhodamine B was released in a slow and sustained manner for 112 days. Its release rate was affected by drug loading and scaffold surface architecture. Release of rhodamine B from the scaffolds followed the Higuchi diffusion model. Other drugs, namely, doxorubicin and lidocaine hydrochloride, were also effectively loaded into and released from the scaffolds. Cell attachment study demonstrated potential for the scaffolds to provide attachment platforms for tissue regeneration.

Adult Cardiac Progenitor Cell Aggregates Exhibit Survival Benefit Both In Vitro and In Vivo

Abstract: Background: A major hurdle in the use of exogenous stems cells for therapeutic regeneration of injured myocardium remains the poor survival of implanted cells. To date, the delivery of stem cells into myocardium has largely focused on implantation of cell suspensions. Methodology and Principal Findings: We hypothesize that delivering progenitor cells in an aggregate form would serve to mimic the endogenous state with proper cell-cell contact, and may aid the survival of implanted cells. Microwell methodologies allow for the culture of homogenous 3D cell aggregates, thereby allowing cell-cell contact. In this study, we find that the culture of cardiac progenitor cells in a 3D cell aggregate augments cell survival and protects against cellular toxins and stressors, including hydrogen peroxide and anoxia/reoxygenation induced cell death. Moreover, using a murine model of cardiac ischemia-reperfusion injury, we find that delivery of cardiac progenitor cells in the form of 3D aggregates improved in vivo survival of implanted cells. Conclusion: Collectively, our data support the notion that growth in 3D cellular systems and maintenance of cell-cell contact improves exogenous cell survival following delivery into myocardium. These approaches may serve as a strategy to improve cardiovascular cell-based therapies.

Mastery learning in the context of university education

Abstract: Developed by Benjamin Bloom in the 1970s, Mastery Learning (ML) is a pedagogical approach that aims to circumvent the problems of conventional group-based teaching and one-to-one individual tutoring, so that better academic performance can be achieved in a more realistic and cost-effective manner. While ML has consistently produced positive effects on the students’ academic and affective outcomes, the amplitude of its benefit has been the subject of frequent contentions. The discrepancies are primarily due to the interplay of multiple extraneous factors that can either diminish or promote the success of ML. Bearing in mind the numerous factors capable of inf luencing the overall effectiveness of ML, is ML still amendable for university education in the 21st century? This review will first provide background to ML, followed by the merits and issues associated with its use. Different factors that can affect the effectiveness of ML will subsequently be examined. Lastly, modifications to better tailor ML for university education will be suggested and discussed. It was found that several unique features of the university curriculum promote the use of ML. ML can be further modified to better suit university education by combining with modern information technology and other effective teaching methods.

Clinical therapeutics for phenylketonuria.

Abstract: Phenylketonuria was amongst the first of the metabolic disorders to be characterised, exhibiting an inborn error in phenylalanine metabolism due to a functional deficit of the enzyme phenylalanine hydroxylase. It affects around 700,000 people around the globe. Mutations in the gene coding for hepatic phenylalanine hydroxylase cause this deficiency resulting in elevated plasma phenylalanine concentrations, leading to cognitive impairment, neuromotor disorders and related behavioural symptoms. Inception of low phenylalanine diet in the 1950s marked a revolution in the management of phenylketonuria and has since been a vital element of all therapeutic regimens. However, compliance to dietary therapy has been found difficult and newer supplement approaches are being examined. The current development of gene therapy and enzyme replacement therapeutics may offer promising alternatives for the management of phenylketonuria. This review outlines the pathological basis of phenylketonuria, various treatment regimes, their associated challenges and the future prospects of each approach. Briefly, novel drug delivery systems which can potentially deliver therapeutic strategies in phenylketonuria have been discussed.