Papers by Dr Md Enamul Hoque
This research aims to fabricate hybrid 3D scaffolds for potential tissue engineering (TE) applica... more This research aims to fabricate hybrid 3D scaffolds for potential tissue engineering (TE) applications. The 3D scaffolds were fabricated with the hybrid polymeric materials of polycaprolactone (PCL) and polyethylene glycol (PEG) using an in-house built desktop robot based rapid prototyping (DRBRP) system. The fabricated scaffolds were characterized morphologically and mechanically investigating the effects of process parameters such as, extrusion pressure, liquefier temperature and dispensing speed on scaffolds' properties. The increase of temperature from 60 1C to 70 1C resulted in increase of filament diameter from 416.7 7 21.7 μm to 508.0 7 25.5 μm and thus elastic modulus from 276 7 1.90 MPa to 293 7 1.49 MPa. Similarly, the increase of pressure from 5 bars to 7 bars increased the filament diameter from 387.5 7 18.5 μm to 416.77 21.7 μm and consequently, elastic modulus from 276 7 1.90 MPa to 293 7 1.49 MPa. However, the increase in deposition speed from 3 mm/s to 5 mm/s unlikely decreased the filament diameter from 508.3 7 25.5 μm to 304.67 15.8 μm, and as a result the elastic modulus decreased from 293 7 2.10 MPA to 275 7 5.67 MPa. The results evidenced the efficacy of the PCL/PEG hybrid material to be processed into 3D scaffolds via DRBRP system for potential TE applications.
This research focuses on synthesis and characterization of sago starch-mixed LDPE biodegradable p... more This research focuses on synthesis and characterization of sago starch-mixed LDPE biodegradable polymer. Firstly, the effect of variation of starch content on mechanical property (elongation at break and Young's modulus) and biodegradability of the polymer was studied. The LDPE was combined with 10%, 30%, 50%, and 70% of sago for this study. Then how the cross-linking with trimethylolpropane triacrylate (TMPTA) and electron beam (EB) irradiation influence the mechanical and thermal properties of the polymer was investigated. In the 2nd study, to avoid overwhelming of data LDPE polymer was incorporated with only 50% of starch. The starch content had direct influence on mechanical property and biodegradability of the polymer. The elongation at break decreased with increase of starch content, while Young's modulus and mass loss (i.e., degradation) were found to increase with increase of starch content. Increase of cross-linker (TMPTA) and EB doses also resulted in increased Young's modulus of the polymer. However, both cross-linking and EB irradiation processes rendered lowering of polymer's melting temperature. In conclusion, starch content and modification processes play significant roles in controlling mechanical, thermal, and degradation properties of the starch-mixed LDPE synthetic polymer, thus providing the opportunity to modulate the polymer properties for tailored applications.
design scaffolds. Overall, the characterization results suggest that the hybrid-design scaffolds ... more design scaffolds. Overall, the characterization results suggest that the hybrid-design scaffolds offer better optimized properties that could be of great value for regenerative therapies.
This research focuses on synthesis and characterization of sago starch-mixed LDPE biodegradable p... more This research focuses on synthesis and characterization of sago starch-mixed LDPE biodegradable polymer. Firstly, the effect of variation of starch content on mechanical property (elongation at break and Young's modulus) and biodegradability of the polymer was studied. The LDPE was combined with 10%, 30%, 50%, and 70% of sago for this study. Then how the cross-linking with trimethylolpropane triacrylate (TMPTA) and electron beam (EB) irradiation influence the mechanical and thermal properties of the polymer was investigated. In the 2nd study, to avoid overwhelming of data LDPE polymer was incorporated with only 50% of starch. The starch content had direct influence on mechanical property and biodegradability of the polymer. The elongation at break decreased with increase of starch content, while Young's modulus and mass loss (i.e., degradation) were found to increase with increase of starch content. Increase of cross-linker (TMPTA) and EB doses also resulted in increased Young's modulus of the polymer. However, both cross-linking and EB irradiation processes rendered lowering of polymer's melting temperature. In conclusion, starch content and modification processes play significant roles in controlling mechanical, thermal, and degradation properties of the starch-mixed LDPE synthetic polymer, thus providing the opportunity to modulate the polymer properties for tailored applications.
Stem cells are a promising source of cells for regenerative medicine. However, little is known ab... more Stem cells are a promising source of cells for regenerative medicine. However, little is known about the mechanisms regulating differentiation. Many studies differentiating embryonic stem (ES) cells have focused on embryoid bodies (3-dimensional cyst-like structures grown in suspension) that spontaneously differentiate into all three germ layers. Other studies have used 2-dimensional cell monolayers, changing substrate coatings on the culture surfaces and medium composition, to induce differentiation. Few studies have used physical forces or cues, such as culture in 3D scaffolds, to induce differentiation. The objective of this study is to determine the effect of culture in 3D collagen type I gels on the differentiation of mouse ES cells.
Synthetic polymers have attracted much attention in tissue engineering due to their ability to mo... more Synthetic polymers have attracted much attention in tissue engineering due to their ability to modulate biomechanical properties. This study investigated the feasibility of processing poly(e-caprolactone) (PCL) homopolymer, PCL-poly(ethylene glycol) (PEG) diblock, and PCL-PEG-PCL triblock copolymers into three-dimensional porous scaffolds. Properties of the various polymers were investigated by dynamic thermal analysis. The scaffolds were manufactured using the desktop robot-based rapid prototyping technique. Gross morphology and internal three-dimensional structure of scaffolds were identified by scanning electron microscopy and micro-computed tomography, which showed excellent fusion at the filament junctions, high uniformity, and complete interconnectivity of pore networks. The influences of process parameters on scaffolds' morphological and mechanical characteristics were studied. Data confirmed that the process parameters directly influenced the pore size, porosity, and, consequently, the mechanical properties of the scaffolds. The in vitro cell culture study was performed to investigate the influence of polymer nature and scaffold architecture on the adhesion of the cells onto the scaffolds using rabbit smooth muscle cells. Light, scanning electron, and confocal laser microscopy showed cell adhesion, proliferation, and extracellular matrix formation on the surface as well as inside the structure of both scaffold groups. The completely interconnected and highly regular honeycomb-like pore morphology supported bridging of the pores via cell-to-cell contact as well as production of extracellular matrix at later time points. The results indicated that the incorporation of hydrophilic PEG into hydrophobic PCL enhanced the overall hydrophilicity and cell culture performance of PCL-PEG copolymer. However, the scaffold architecture did not significantly influence the cell culture performance in this study.
Hybrid design strategy in scaffold development is currently being explored in order to obtain new... more Hybrid design strategy in scaffold development is currently being explored in order to obtain new scaffold geometries in favor of efficient cell attachment and growth in tissue engineering applications. This current study investigates the cell culture performance on the single and hybrid design PCL scaffolds manufactured via in-house built desktop robot based rapid prototyping (DRBRP) system. Single design scaffolds were developed by drawing fibers at a specific angle (e.g., 30°, 45°, 60° or 90°) throughout the scaffold unit. Unlikely, the hybrid design scaffolds integrated two or more lay-down patterns (e.g., 30-45-60-900) in the same scaffold unit. In vitro cell culture studies were performed on both single and hybrid design scaffolds by using human osteoprogenitor cells. Light, scanning electron and confocal laser microscopy (CLM) showed cell attachment, proliferation, and extracellular matrix production on the surface as well as inside the scaffold architecture. Hybrid design scaffolds demonstrated better performance in cell culture studies than the single design scaffolds. The overall results suggest that the hybrid scaffolds offer better optimized properties, which can meet the functional and biological requirements of living tissues for regenerative therapies.
The demand for fuel oil is ever increasing with the advance of the modern world, whereas worldwid... more The demand for fuel oil is ever increasing with the advance of the modern world, whereas worldwide reserves of fossil oils are diminishing at an alarming rate. However, there exist large stockpiles of vegetable oil feedstocks that could be exploited to produce fuel oil, called biodiesel with the aid of biotechnology. Initially, the biodiesel produced from vegetable oil did not attract much attention because of its high cost. However, the recent increase in petroleum prices and the uncertainties of petroleum availability led to the renewal of interest in biodiesel production from such sustainable resources (i.e., vegetable oil feedstocks). This research focuses on the production of biodiesel from plant resources, and further investigates the influences of key process parameters, such as the molar ratio of methanol to oil, catalyst concentration, reaction temperature, reaction period and stirring speed on the biodiesel yield. This investigation is to determine the optimum process parameters for maximum biodiesel yield. The biodiesel was produced from three vegetable oil feedstocks, namely palm, soybean and sunflower oil via a transesterification process. It was observed that all the process parameters significantly influenced the biodiesel yield. The maximum biodiesel yields for palm, sunflower and soybean oil feedstocks were found to be 87.5%, 83.6% and 80.2%, respectively at optimum condition. The results suggest that through proper optimization of the process parameters the biodiesel yields could be maximized. In conclusion, the production of biodiesel from plant resources would be regarded as a sustainable solution to the ever increasing demand of fuel oils.
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Papers by Dr Md Enamul Hoque