Development of a 3d bioprinting system, characterisation of bioink and printing microspheroids of hela cells

In Malaysia, Industrialised Building System (IBS) has been recognised as a potential solution in improving the deliverables of construction projects. However, the acceptance of this modern technology is still low. Most of the construction players prefer the conventional construction method which leads to a longer duration, lower productivity and poor quality of the building. The adoption of IBS requires systematic project management to ensure the best output in improving construction deliverables. Improper IBS project management can generate physical and non-physical waste in the production and construction tasks. This research aimed to evaluate on how to prevent waste and any types of loss during IBS construction by implementing lean management. This research examined the relation between critical factors in implementing lean management technique using the Interpretative Structural Modelling (ISM) method. In establishing ISM model, 51 influencing factors in implementing lean management based on lean construction key principles had been identified throughout an extensive literature review. The results from questionnaire survey identified 18 critical success factors for lean management adoption in IBS application. For further investigation, semi-structured interviews were conducted to collect the qualitative data for the critical factors. ISM analysis method was used to study the association between each critical success factor. The initial model was developed to promote the adoption of lean management technique in IBS construction. Deeper ISM analysis established a Matrice d’Impacts Croisés Multiplication Appliqués à un Classement (MICMAC). The MICMAC results in this research demonstrated that four important factors are categorised as Independent / Driving factors namely ‘planning’, ‘educate labour’, ‘modularisation’, and ‘standardisation’. These factors were explored in detail to drive the performance elements categorised in Dependent factor which is ‘reduce production time’. The findings provide a model that prioritised the critical success factors which lead to framework of lean management application in IBS production

Development of a twin-head infusion pump for micromixing

Mixing is a crucial process in most of the industrial technology such as the operation of chemicals and fermentation reactors, combustion engines, polymer blends, and pharmaceutical formulations [1]. For handling a smaller volume of liquid, micromixing is a suitable method that can be applied. Micromixing (micromixer) is one of the microfluidic functions for mixing and blending liquids as precursors for biological process such as cell activation, enzyme reaction, and drug delivery system [2, 3]. There are several advantages of applying microfluidic device (micromixer) in the chemical technological processes such as processing accuracy, efficiency, minimum usage of reagents and ease of disposing of devices and fluids [3]. Basically, micromixers are categorised into passive and active micromixers. Passive micromixer consists of no moving parts and free from additional friction. It does not use external forces, fully dependent on molecular diffusion and chaotic advection for mixing process [4]. In contrast to active micromixers, external forces are applicable to active micromixers by implementing moving elements either within the microchannels, a time-variant, or a pressure field [5]. To create the pressure field differences for moving the liquid within the micromixer, an infusion pump is usually applied

Generation of HeLa spheroids in Ca-alginate-PEG microbeads using flicking technique as an improved three-dimensional cell culture system

In a conventional three-dimensional (3D) cell culture system based on microencapsulation, the calcium alginate microcapsules tend to rupture within 7 days of culture, causing unwanted cell leakage. The microencapsulation based on flicking model of calcium-alginate-polyethylene glycol (Ca-alg-PEG) was proposed to rectify this problem. An analytical model to simulate the flicking process based on the deflection of a needle cantilever was also successfully developed and used to predict the size of the microbeads. The size of the microbeads were ranged from 300 to 500 μm and it is controlled by varying the liquid flow rate from 4.8 to 366 μL/min and flicking speed from 70 to 120 rpm. Under a flicking force of 0.58 N, uniform sized and spherical shaped Ca-alginate-PEG microbeads were produced at a liquid flow rate of 40 μL/min and a flicking rate of 100 rpm. The microbeads were characterized by Field Emission Scanning Microscopy, Atomic Force Microscopy, Raman Spectroscopy and Nanoindentation, and the results indicated improved bio-physical properties of the ca-alginate microbeads after added with PEG. The cell viability test demonstrated that Ca-alginate-PEG microbeads were able to support the growth of viable HeLa cells into spheroids. Resilient calcium-alginate-polyethylene glycol (Ca-alg-PEG) microbeads were found to be able to last up to 15 days before rupturing and greatly reduced the cell leakage problem