Tissue engineering (TE) research serves to overcome the major obstacles in organ transplantation. This paper summarizes the progress of TE in Malaysia. The online database of Elsevier’s SCOPUS was accessed. Publications related to TE from 1960 till 2017 were scrutinized. The results show an increasing trend in tissue engineering research and development in Malaysia. The search result identified and examined 264 original article publications. It is hoped that the outcomes of this study could serve as a point of reference for researchers on the status of TE research and development in Malaysia. The findings of this study could assist TE researchers in Malaysia to identify the strengths, weaknesses, opportunities and obstacles towards further enhancement in their activities. Consolidating, realigning and re-strategizing those initiatives should also be seen within the context of nurturing potential and budding researchers in TE.
This paper examines the safety and efficacy of non-viral gene transfer in cartilage tissue engineering (TE) from the worldview of Islam. The first clinical trial treating adenosine deaminase deficient patients conducted in 1990 has triggered the development of gene transfer technology. The potential of gene transfer is further explored in TE field with the hope that it could prosper the regenerative medicine application. However, ethical issues become important when it comes to application of new treatment modalities, primarily in gene transfer because of genetic modification influences the basis of life - the DNA. Besides ethical issue, the application of gene transfer in treating diseases also attract views from religious context. The questions on the techniques to administer the gene in human, social acceptance of genetically modified cell and adverse effects from it are still debatable and unresolved. Apart from that dilemma, both safety and efficacy issues are raised due to the scientific uncertainty and social perception of the technology. Despite countless number of encouraging findings and recommendations by the proponents of
the technology, gene transfer is currently available only in the research setting. The established guidelines are used to complement and provide the necessary foundations in discussing the aspects involved in the incorporation of gene transfer with cartilage TE. Relevant Islamic input are identified and aligned to those particular guidelines. It is hoped that the integration of Islamic inputs in the existing guidelines could suggest the safest approach in treating cartilage degenerative disease through gene transfer and TE.
Organ repair, regeneration, and transplantation are constantly in demand due to various acute, chronic, congenital, and infectious diseases. Apart from traditional remedies, tissue engineering (TE) is among the most effective methods for the repair of damaged tissues via merging the cells, growth factors, and scaffolds. With regards to TE scaffold fabrication technology, polyurethane (PU), a high-performance medical grade synthetic polymer and bioactive material has gained significant attention. PU possesses exclusive biocompatibility, biodegradability, and modifiable chemical, mechanical and thermal properties, owing to its unique structure-properties relationship. During the past few decades, PU TE scaffold bioactive properties have been incorporated or enhanced with biodegradable, electroactive, surface-functionalised, ayurvedic products, ceramics, glass, growth factors, metals, and natural polymers, resulting in the formation of modified polyurethanes (MPUs). This review focuses on the recent advances of PU/MPU scaffolds, especially on the biomedical applications in soft and hard tissue engineering and regenerative medicine. The scientific issues with regards to the PU/MPU scaffolds, such as biodegradation, electroactivity, surface functionalisation, and incorporation of active moieties are also highlighted along with some suggestions for future work.
Molluscan shells are attracting research interest due to the diverse application properties possessed. As shells are very similar to bones, this study was conducted to analyze the mineral and physiochemical composition of Cockle (Anadara granosa) shell and three other types of molluscan shell, namely Strombus canarium, Oliva sayana and Terebra dislocata as potential biomaterial for bone tissue engineering applications. Approximately 200 g of shells from each species were processed and powdered for the purpose of this study. Carbon was analyzed using the carbon analyzer while minerals and heavy metals through ICP-MS. The phase purity and crystallographic structures of the powders were identified using X-Ray Diffractometer (XRD) while the chemical functionality was determined using the Fourier transform infrared (FTIR) spectrophotometer. The analysis showed that Cockle shells contained higher content of calcium and carbon including varying amount of other minor elements comparatively. However, all four types of shell powders were found to contain below detectable levels of toxic elements. Physiochemical analysis on phase purity and crystallographic structures showed similar characteristics of carbonate group present in all four shell types. A predominantly aragonite form of calcium carbonate was detected in both XRD diffractogram and FTIR spectra for all samples. Our findings demonstrated that different types of molluscan shells have almost similar mineral and physiochemical characteristics and a predominantly aragonite form of calcium carbonate that provides a strong basis for their use as a potential bone tissues engineering material.
Tissue engineering scaffolds with oxygen generating elements have shown to be able to increase the level of oxygen and cell survivability in specific conditions. In this study, biphasic calcium phosphate (BCP) scaffolds with the composition of 60% hydroxyapatite (HA) and 40% beta-tricalcium phosphate (β-TCP), which have shown a great potential for bone tissue engineering applications, were fabricated by a direct-write assembly (robocasting) technique. Then, the three-dimensional (3D)-printed scaffolds were coated with different ratios of an oxygen releasing agent, calcium peroxide (CPO), which encapsulated within a polycaprolactone (PCL) matrix through dip-coating, and used for in situ production of oxygen in the implanted sites. The structure, composition and morphology of the prepared scaffolds were characterized by different techniques. The oxygen release kinetics and biological investigations of the scaffolds were also studied in vitro. The results showed that oxygen release behaviour was sustained and dependant on the concentration of CPO encapsulated in the PCL coating matrix. It was also demonstrated that the coated scaffolds, having 3% CPO in the coating system, could provide a great potential for promoting bone ingrowth with improving osteoblast cells viability and proliferation under hypoxic conditions. The findings indicated that the prepared scaffolds could play a significant role in engineering of large bone tissue implants with limitations in oxygen diffusion.
Angiogenicity is one of the essential components to enable tissue function. It is important to develop a construct that would help in catering oxygen and nutrient to the engineered tissue area. Thus, this study aims to investigate the attachment, spreading and growth of stem cells from human exfoliated deciduous teeth (SHED) on human AM (HAM) with or without vascular endothelial growth factor (VEGF) using scanning electron microscope (SEM), and indirectly see the potential of the HAM as a scaffold to promote angiogenic micro-environment. Since day 1, there were continuous changes of the cell morphology until day 28, SHED treated with VEGF seemed to change its shape from fibroblast-like into a round-shape cell, similar structure as an endotheliallike cell. The structures of filopodia-like were also observed on the treated SHED. SHED without VEGF treatment showed only normal morphological growth on HAM. VEGF is a protein produced to stimulate angiogenesis, and is believed to contribute to the morphological changes of SHED seeded on HAM. This indicates that HAM could be used as a scaffold to allow SHED differentiation into endothelial-like cells with the induction of VEGF.
Multipotent stem cells derived from human exfoliated deciduous teeth (SHED) represent a promising cell source for tissue regeneration. In the present study we decided to test the inductive effect of chitosan and transforming growth factor-β1 (TGFβ1) as a scaffold/factor combination on SHED proliferation and osteogenic differentiation.
The aim of this research is to develop biocompatible nanofibrous mats using hydroxyethyl cellulose with improved cellular adhesion profiles and stability and use these fibrous mats as potential scaffold for skin tissue engineering. Glutaraldehyde was used to treat the scaffolds water insoluble as well as improve their biostability for possible use in biomedical applications. Electrospinning of hydroxyethyl cellulose (5 wt%) with poly(vinyl alcohol) (15 wt%) incorporated with and without collagen was blended at (1:1:1) and (1:1) ratios, respectively, and was evaluated for optimal criteria as tissue engineering scaffolds. The nanofibrous mats were crosslinked and characterized by scanning electron microscope, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. Scanning electron microscope images showed that the mean diameters of blend nanofibers were gradually increased after chemically crosslinking with glutaraldehyde. Fourier transform infrared spectroscopy was carried out to understand chemical interactions in the presence of aldehyde groups. Thermal characterization results showed that the stability of hydroxyethyl cellulose/poly(vinyl alcohol) and hydroxyethyl cellulose/poly(vinyl alcohol)/collagen nanofibers was increased with glutaraldehyde treatment. Studies on cell-scaffolds interaction were carried out by culturing human fibroblast (hFOB) cells on the nanofibers by assessing the growth, proliferation, and morphologies of cells. The scanning electron microscope results show that better cell proliferation and attachment appeared on hydroxyethyl cellulose/poly(vinyl alcohol)/collagen substrates after 7 days of culturing, thus, promoting the potential of electrospun scaffolds as a promising candidate for tissue engineering applications.
In this study, a novel fibrous membrane of hydroxyethyl cellulose (HEC)/poly(vinyl alcohol) blend was successfully fabricated by electrospinning technique and characterized. The concentration of HEC (5%) with PVA (15%) was optimized, blended in different ratios (30-50%) and electrospun to get smooth nanofibers. Nanofibrous membranes were made water insoluble by chemically cross-linking by glutaraldehyde and used as scaffolds for the skin tissue engineering. The microstructure, morphology, mechanical and thermal properties of the blended HEC/PVA nanofibrous scaffolds were characterized by scanning electron microscope, Fourier transform infrared spectroscopy, differential scanning colorimetry, universal testing machine and thermogravimetric analysis. Cytotoxicity studies on these nanofibrous scaffolds were carried out using human melanoma cells by the MTT assays. The cells were able to attach and spread in the nanofibrous scaffolds as shown by the SEM images. These preliminary results show that these nanofibrous scaffolds that supports cell adhesion and proliferation is promising for skin tissue engineering.
The four heart valves represented in the mammalian hearts are responsible for maintaining unidirectional, non-hinder blood flow. The heart valve leaflets synchronically open and close approximately 4 million times a year and more than 3 billion times during the life. Valvular heart dysfunction is a significant cause of morbidity and mortality around the world. When one of the valves malfunctions, the medical choice is may be to replace the original valves with an artificial one. Currently, the mechanical and biological artificial valves are clinically used with some drawbacks. Tissue engineering heart valve concept represents a new technique to enhance the current model. In tissue engineering method, a three-dimensional scaffold is fabricated as the template for neo-tissue development. Appropriate cells are seeded to the matrix in vitro. Various approaches have been investigated either in scaffold biomaterials and fabrication techniques or cell source and cultivation methods. The available results of ongoing experiments indicate a promising future in this area (particularly in combination of bone marrow stem cells with synthetic scaffold), which can eliminate the need for lifelong anti-coagulation medication, durability and reoperation problems.
Introduction: Oral cancer is the sixth most common malignancy in the world. It is a major concern in Southeast Asia primarily due to betel quid chewing, smoking, and alcohol consumption. In Malaysia, oral cancer related cases accounts for 1.55% of the cause of deaths. Despite recent advances in cancer diagnoses and therapies, the survival rate of oral cancer patients only reached 50% in the last few decades. Tissue engineering (TE) principles may pro-vide new technology platforms to study mechanisms of angiogenesis and tumour cell growth as well as potentially tumour cell spreading in cancer research. The use of biomaterial, appropriate cell source and proper signalling mol-ecules are vital components of TE. Collagen biomaterial are widely used scaffold or membrane in oral application. Nevertheless, no review has been performed on the its usage for the study of oral cancer. This study aimed to sys-tematically review the use of collagen scaffold in oral cancer application. Methods: Research articles were searched using Scopus, Pubmed and Web of Science (WOS) databases. The keywords were limited to “collagen membrane OR collagen scaffold” AND “oral cancer”. Results: Initial search yielded 61 papers (Scopus:37, Pubmed: 12, WOS: 12). Further scrutinization of the papers based on the inclusion criteria resulted total of 3 papers. Two of the papers used collagen membrane for regeneration of oral mucosal defect and increment of alveolar ridge height post-surgery. The remaining paper utilize collagen biomaterial as scaffold for the culture of adenoid cystic carcinoma (ACC) cells. All papers reported significant role of collagen biomaterial in terms of tissue formation, healing scaffold and cellular proliferation. Conclusion: Collagen utilization as biomaterial offers potential use for regeneration of oral related structures as well providing useful model for therapeutics anti-cancer research.
In skin tissue engineering, a biodegradable scaffold is usually used where cells grow, produce its own cytokines, growth factors, and extracellular matrix, until the regenerated tissue gradually replaces the scaffold upon its degradation. However, the role of non-biodegradable scaffold remains unexplored. This study investigates the potential of a non-biodegradable bacterial nanocellulose/acrylic acid (BNC/AA) hydrogel to transfer human dermal fibroblasts (HDF) to the wound and the resulting healing effects of transferred HDF in athymic mice. Results demonstrated that the fabricated hydrogel successfully transferred >50% of HDF onto the wound site within 24 h, with evidence of HDF detected on day 7. The gene and protein study unveiled faster wound healing in the hydrogel with HDF group and characterized more mature newly formed skin microstructure on day 7, despite no visible differences. These findings give a new perspective regarding the role of non-biodegradable materials in skin tissue engineering, in the presence of exogenous cells, mainly at the molecular level.
For dental implants, it is vital that an initial soft tissue seal is achieved as this helps to stabilize and preserve the peri-implant tissues during the restorative stages following placement. The study of the implant-soft tissue interface is usually undertaken in animal models. We have developed an in vitro three-dimensional tissue-engineered oral mucosal model (3D OMM), which lends itself to the study of the implant-soft tissue interface as it has been shown that cells from the three-dimensional OMM attach onto titanium (Ti) surfaces forming a biological seal (BS). This study compares the quality of the BS achieved using the three-dimensional OMM for four types of Ti surfaces: polished, machined, sandblasted and anodized (TiUnite). The BS was evaluated quantitatively by permeability and cell attachment tests. Tritiated water (HTO) was used as the tracing agent for the permeability test. At the end of the permeability test, the Ti discs were removed from the three-dimensional OMM and an Alamar Blue assay was used for the measurement of residual cells attached to the Ti discs. The penetration of the HTO through the BS for the four types of Ti surfaces was not significantly different, and there was no significant difference in the viability of residual cells that attached to the Ti surfaces. The BS of the tissue-engineered oral mucosa around the four types of Ti surface topographies was not significantly different.
A three dimensional tissue-engineered human oral mucosal model (3D OMM) used in the investigation of implant-soft tissue interface was recently reported. The aim of this study was to examine the ultrastructural features of soft tissue attachment to various titanium (Ti) implant surfaces based on the 3D OMM. Two techniques, that is, focus ion beam (FIB) and electropolishing techniques were used to prepare specimens for transmission electron microscopic (TEM) analysis of the interface. The 3D OM consisting of both epithelial and connective tissue layers was constructed by co-culturing human oral keratinocytes and fibroblasts onto an acellular dermis scaffold. Four types of Ti surface topographies were tested: polished, machined (turned), sandblasted, and TiUnite. The specimens were then processed for TEM examination using FIB (Ti remained) and electropolishing (Ti removed) techniques. The FIB sections showed some artifact and lack of details of ultrastructural features. In contrast, the ultrathin sections prepared from the electropolishing technique showed a residual Ti oxide layer, which preserved the details for intact ultrastructural interface analysis. There was evidence of hemidesmosome-like structures at the interface on the four types of Ti surfaces, which suggests that the tissue-engineered oral mucosa formed epithelial attachments on the Ti surfaces.
Hydroxyapatite (HA) has been widely used as a scaffold in tissue engineering. HA possesses high mechanical stress and exhibits particularly excellent biocompatibility owing to its similarity to natural bone. Nonetheless, this ceramic scaffold has limited applications due to its apparent brittleness. Therefore, this had presented some difficulties when shaping implants out of HA and for sustaining a high mechanical load. Fortunately, these drawbacks can be improved by combining HA with other biomaterials. Starch was heavily considered for biomedical device applications in favor of its low cost, wide availability, and biocompatibility properties that complement HA. This review provides an insight into starch/HA composites used in the fabrication of bone tissue scaffolds and numerous factors that influence the scaffold properties. Moreover, an alternative characterization of scaffolds via dielectric and free space measurement as a potential contactless and nondestructive measurement method is also highlighted.
Supramolecular hydrogels, formed by noncovalent crosslinking of polymeric chains in water, constitute an interesting class of materials that can be developed specifically for drug delivery and biomedical applications. The biocompatibility, stimuli responsiveness to various external factors, and powerful functionalization capacity of these polymeric networks make them attractive candidates for novel advanced dosage form design.
Lack of suitable auto/allografts has been delaying surgical interventions for the treatment of numerous disorders and has also caused a serious threat to public health. Tissue engineering could be one of the best alternatives to solve this issue. However, deficiency of oxygen supply in the wounded and implanted engineered tissues, caused by circulatory problems and insufficient angiogenesis, has been a rate-limiting step in translation of tissue-engineered grafts. To address this issue, we designed oxygen-releasing electrospun composite scaffolds, based on a previously developed hybrid polymeric matrix composed of poly(glycerol sebacate) (PGS) and poly(ε-caprolactone) (PCL). By performing ball-milling, we were able to embed a large percent of calcium peroxide (CP) nanoparticles into the PGS/PCL nanofibers able to generate oxygen. The composite scaffold exhibited a smooth fiber structure, while providing sustainable oxygen release for several days to a week, and significantly improved cell metabolic activity due to alleviation of hypoxic environment around primary bone-marrow-derived mesenchymal stem cells (BM-MSCs). Moreover, the composite scaffolds also showed good antibacterial performance. In conjunction to other improved features, such as degradation behavior, the developed scaffolds are promising biomaterials for various tissue-engineering and wound-healing applications.
Porous ceramic scaffolds are widely studied in the tissue engineering field due to their potential in medical applications as bone substitutes or as bone-filling materials. In this study, porous hydroxyapatite (HA) was produced via polymer replication method. Polyurethane (PU) sponge was selected as the template and synthetic binder, polyvinyl alcohol (PVA) was used in this study. Fixed formulation of HA powder, distilled water and PVA (40:60:3) were prepared and stirred at a constant 4 hours time. PU sponges with 30 ppi and 60 ppi size were cut and impregnated in slurry using vacuum and roller infiltration methods. The microstructures were observed by using field emission scanning electron microscope (FESEM). The results obtained indicate that vacuum infiltration method and 60 ppi template pore size exhibited the highest compressive strength with moderate average strut thickness and lowest average pore size compared to samples produced by roller infiltration method at different template pore size.
The chondrogenic efficacy of aloe vera blended collagen-chitosan (COL-CS-AV) porous scaffold was investigated using articular chondrocytes in a standard condition. Cytocompatibility was analyzed using fluorescent dyes (calcein AM/ethidium bromide) and the viable cells were quantified by MTT assay. Glycosaminoglycan (GAG) content of ECM was estimated by using 1, 9-Dimethyl methylene Blue (DMMB). The total RNA content was quantified and the cartilage specific genes (col2a1, Acan) were amplified by reverse transcription-PCR from the cell lysate of the scaffolds. Histological examination was made using Haematoxylin and Eosin (H&E), safranin-O, masson's trichrome, alcian blue, and alizarin red to stain the specific component of ECM secreted on the construct. The cartilage specific collagen type II was estimated by immunohistochemistry using monoclonal type II collagen antibody. The results of these studies proved that COL-CS-AV scaffold has more chondrogenic efficacy than COL-CS, thus the aloe vera blend COL-CS-AV scaffold might be used as suitable candidate for cartilage tissue engineering.
Ayurveda oil contains numerous source of biological constituents which plays an important role in reducing the pain relief caused during bone fracture. The aim of the study is to fabricate the polyurethane (PU) scaffold for bone tissue engineering added with ayurveda amla oil using electrospinning technique. Scanning Electron Microscopy (SEM) analysis showed that the fabricated nanocomposites showed reduced fiber diameter (758 ± 185.46 nm) than the pristine PU (890 ± 116.91 nm). Fourier Infrared Analysis (FTIR) revealed the existence of amla oil in the PU matrix by hydrogen bond formation. The contact angle results revealed the decreased wettability (116° ± 1.528) of the prepared nanocomposites compared to the pure PU (100° ± 0.5774). The incorporation of amla oil into the PU matrix improved the surface roughness. Further, the coagulation assay indicated that the addition of amla oil into PU delayed the blood clotting times and exhibited less toxic to red blood cells. Hence, the fabricated nanocomposites showed enhanced physicochemical and better blood compatibility parameters which may serve as a potential candidate for bone tissue engineering.