Displaying publications 1 - 20 of 79 in total

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  1. Al-Saffar Y, Moo EK, Pingguan-Murphy B, Matyas J, Korhonen RK, Herzog W
    Connect Tissue Res, 2023 May;64(3):294-306.
    PMID: 36853960 DOI: 10.1080/03008207.2023.2166500
    Cartilage cracks disrupt tissue mechanics, alter cell mechanobiology, and often trigger tissue degeneration. Yet, some tissue cracks heal spontaneously. A primary factor determining the fate of tissue cracks is the compression-induced mechanics, specifically whether a crack opens or closes when loaded. Crack deformation is thought to be affected by tissue structure, which can be probed by quantitative polarized light microscopy (PLM). It is unclear how the PLM measures are related to deformed crack morphology. Here, we investigated the relationship between PLM-derived cartilage structure and mechanical behavior of tissue cracks by testing if PLM-derived structural measures correlated with crack morphology in mechanically indented cartilages.

    METHODS: Knee joint cartilages harvested from mature and immature animals were used for their distinct collagenous fibrous structure and composition. The cartilages were cut through thickness, indented over the cracked region, and processed histologically. Sample-specific birefringence was quantified as two-dimensional (2D) maps of azimuth and retardance, two measures related to local orientation and degree of alignment of the collagen fibers, respectively. The shape of mechanically indented tissue cracks, measured as depth-dependent crack opening, were compared with azimuth, retardance, or "PLM index," a new parameter derived by combining azimuth and retardance.

    RESULTS: Of the three parameters, only the PLM index consistently correlated with the crack shape in immature and mature tissues.

    CONCLUSION: In conclusion, we identified the relative roles of azimuth and retardance on the deformation of tissue cracks, with azimuth playing the dominant role. The applicability of the PLM index should be tested in future studies using naturally-occurring tissue cracks.

  2. Alhalawani AM, Curran DJ, Pingguan-Murphy B, Boyd D, Towler MR
    J Funct Biomater, 2013;4(4):329-57.
    PMID: 24956193 DOI: 10.3390/jfb4040329
    This study investigates the use of gallium (Ga) based glass polyalkenoate cements (GPCs) as a possible alternative adhesive in sternal fixation, post sternotomy surgery. The glass series consists of a Control (CaO-ZnO-SiO2), and LGa-1 and LGa-2 which contain Ga at the expense of zinc (Zn) in 0.08 mol% increments. The additions of Ga resulted in increased working time (75 s to 137 s) and setting time (113 to 254 s). Fourier Transform Infrared (FTIR) analysis indicated that this was a direct result of increased unreacted poly(acrylic acid) (PAA) and the reduction of crosslink formation during cement maturation. LGa samples (0.16 wt % Ga) resulted in an altered ion release profile, particularly for 30 days analysis, with maximum Ca2+, Zn2+, Si4+ and Ga3+ ions released into the distilled water. The additions of Ga resulted in increased roughness and decreased contact angles during cement maturation. The presence of Ga has a positive effect on the compressive strength of the samples with strengths increasing over 10 MPa at 7 days analysis compared to the 1 day results. The additions of Ga had relatively no effect on the flexural strength. Tensile testing of bovine sterna proved that the LGa samples (0.16 wt % Ga) are comparable to the Control samples.
  3. Aminuddin NI, Ahmad R, Akbar SA, Pingguan-Murphy B
    Sci Technol Adv Mater, 2016;17(1):698-714.
    PMID: 27933112
    To understand how cells respond to the nanoscale extracellular environment in vivo, cells from various sources have been cultured on nanoscale patterns fabricated using bottom-up and top-down techniques. Human fetal osteoblasts (hFOBs) and stem cells are some of them and they are known to be overtly responsive to nanoscale topographies - allowing us to investigate the hows and whys of the response in vitro. Information gathered from these in vitro studies could be used to control the cells, i.e. make the stem cells differentiate or retain their characteristics without the use of medium supplements. In this review, hFOB and stem cell responses to nanotopographies are summarized and discussed to shed some light on the influence of patterns on the reactions. Although both types of cells are responsive to nanoscale topographies, the responses are found to be unique to topographical dimension, shape, orientation and the types of cells used. This implies that cellular responses are influenced by multitude of factors and that if done right, cheaper self-assembled nanotopographies can be tailored to control the cells. A new self-assembly, powder-based technique is also included to provide an insight into the future of nanofabrication.
  4. Ataollahi F, Pingguan-Murphy B, Moradi A, Wan Abas WA, Chua KH, Abu Osman NA
    Cytotherapy, 2014 Aug;16(8):1145-52.
    PMID: 24831838 DOI: 10.1016/j.jcyt.2014.01.010
    Numerous protocols for the isolation of bovine aortic endothelial cells have been described in the previous literature. However, these protocols prevent researchers from obtaining the pure population of endothelial cells. Thus, this study aimed to develop a new and economical method for the isolation of pure endothelial cells by introducing a new strategy to the enzymatic digestion method proposed by previous researchers.
  5. Ataollahi F, Pramanik S, Moradi A, Dalilottojari A, Pingguan-Murphy B, Wan Abas WA, et al.
    J Biomed Mater Res A, 2015 Jul;103(7):2203-13.
    PMID: 24733741 DOI: 10.1002/jbm.a.35186
    Extracellular environments can regulate cell behavior because cells can actively sense their mechanical environments. This study evaluated the adhesion, proliferation and morphology of endothelial cells on polydimethylsiloxane (PDMS)/alumina (Al2 O3 ) composites and pure PDMS. The substrates were prepared from pure PDMS and its composites with 2.5, 5, 7.5, and 10 wt % Al2 O3 at a curing temperature of 50°C for 4 h. The substrates were then characterized by mechanical, structural, and morphological analyses. The cell adhesion, proliferation, and morphology of cultured bovine aortic endothelial (BAEC) cells on substrate materials were evaluated by using resazurin assay and 1,1'-dioctadecyl-1,3,3,3',3'-tetramethylindocarbocyanine perchlorate-acetylated LDL (Dil-Ac-LDL) cell staining, respectively. The composites (PDMS/2.5, 5, 7.5, and 10 wt % Al2 O3 ) exhibited higher stiffness than the pure PDMS substrate. The results also revealed that stiffer substrates promoted endothelial cell adhesion and proliferation and also induced spread morphology in the endothelial cells compared with lesser stiff substrates. Statistical analysis showed that the effect of time on cell proliferation depended on stiffness. Therefore, this study concludes that the addition of different Al2 O3 percentages to PDMS elevated substrate stiffness which in turn increased endothelial cell adhesion and proliferation significantly and induced spindle shape morphology in endothelial cells.
  6. Boo, L., Sofiah, S., Selvaratnam, L., Tai, C.C., Pingguan-Murphy, B., Kamarul, T.
    Malays Orthop J, 2009;3(2):16-23.
    MyJurnal
    Purpose:To investigate the feasibilty of using processed human amniotic membrane (HAM) to support the attachment and proliferation of chondrocytes in vitro which it turn can be utilised as a cell delivery vehicle in tissue engineering applications. Methods: Fresh HAM obtained from patients undergoing routine elective ceasarean sections was harvested., processed and dried using either freez drying (FD) or air drying (AD) methods prior to sterilisation by gamma irradiation. Isolated, processed and characterised rabbit autologous chondrolytes were seeded on processsed HAM and cultured for up to three weeks. Cell attachment and proliferation were examined qualitatively using inverted brightfield microcospy. Results: Processed HAM appeared to allow cell attachment when implanted with chrondocytes. Although cells seeded on AD and FD HAM did not appear to attach as strongly as those seeded on glycerol preserved intact human amniotic membrane, these cells to be proliferated in cell culture conditions. Conclusion: Prelimanary results show that processed HAM chondrocyte attachment and proliferation.
  7. Choi JR, Hu J, Feng S, Wan Abas WA, Pingguan-Murphy B, Xu F
    Biosens Bioelectron, 2016 May 15;79:98-107.
    PMID: 26700582 DOI: 10.1016/j.bios.2015.12.005
    Lateral flow assays (LFAs) have currently attracted broad interest for point-of-care (POC) diagnostics, but their application has been restricted by poor quantification and limited sensitivity. While the former has been currently solved to some extent by the development of handheld or smartphone-based readers, the latter has not been addressed fully, particularly the potential influences of environmental conditions (e.g., temperature and relative humidity (RH)), which have not yet received serious attention. The present study reports the use of a portable temperature-humidity control device to provide an optimum environmental requirement for sensitivity improvement in LFAs, followed by quantification by using a smartphone. We found that a RH beyond 60% with temperatures of 55-60°C and 37-40°C produced optimum nucleic acid hybridization and antigen-antibody interaction in LFAs, respectively representing a 10-fold and 3-fold signal enhancement over ambient conditions (25°C, 60% RH). We envision that in the future the portable device could be coupled with a fully integrated paper-based sample-to-answer biosensor for sensitive detection of various target analytes in POC settings.
  8. Choi JR, Pingguan-Murphy B, Wan Abas WA, Yong KW, Poon CT, Noor Azmi MA, et al.
    PLoS One, 2015;10(1):e0115034.
    PMID: 25615717 DOI: 10.1371/journal.pone.0115034
    Adipose tissue-derived stromal cells (ASCs) natively reside in a relatively low-oxygen tension (i.e., hypoxic) microenvironment in human body. Low oxygen tension (i.e., in situ normoxia), has been known to enhance the growth and survival rate of ASCs, which, however, may lead to the risk of tumourigenesis. Here, we investigated the tumourigenic potential of ASCs under their physiological condition to ensure their safe use in regenerative therapy. Human ASCs isolated from subcutaneous fat were cultured in atmospheric O2 concentration (21% O2) or in situ normoxia (2% O2). We found that ASCs retained their surface markers, tri-lineage differentiation potential, and self-renewal properties under in situ normoxia without altering their morphology. In situ normoxia displayed a higher proliferation and viability of ASCs with less DNA damage as compared to atmospheric O2 concentration. Moreover, low oxygen tension significantly up-regulated VEGF and bFGF mRNA expression and protein secretion while reducing the expression level of tumour suppressor genes p16, p21, p53, and pRb. However, there were no significant differences in ASCs telomere length and their relative telomerase activity when cultured at different oxygen concentrations. Collectively, even with high proliferation and survival rate, ASCs have a low tendency of developing tumour under in situ normoxia. These results suggest 2% O2 as an ideal culture condition for expanding ASCs efficiently while maintaining their characteristics.
  9. Choi JR, Pingguan-Murphy B, Wan Abas WA, Noor Azmi MA, Omar SZ, Chua KH, et al.
    Biochem Biophys Res Commun, 2014 May 30;448(2):218-24.
    PMID: 24785372 DOI: 10.1016/j.bbrc.2014.04.096
    Adipose-derived stem cells (ASCs) have been found adapted to a specific niche with low oxygen tension (hypoxia) in the body. As an important component of this niche, oxygen tension has been known to play a critical role in the maintenance of stem cell characteristics. However, the effect of O2 tension on their functional properties has not been well determined. In this study, we investigated the effects of O2 tension on ASCs stemness, differentiation and proliferation ability. Human ASCs were cultured under normoxia (21% O2) and hypoxia (2% O2). We found that hypoxia increased ASC stemness marker expression and proliferation rate without altering their morphology and surface markers. Low oxygen tension further enhances the chondrogenic differentiation ability, but reduces both adipogenic and osteogenic differentiation potential. These results might be correlated with the increased expression of HIF-1α under hypoxia. Taken together, we suggest that growing ASCs under 2% O2 tension may be important in expanding ASCs effectively while maintaining their functional properties for clinical therapy, particularly for the treatment of cartilage defects.
  10. Choi JR, Liu Z, Hu J, Tang R, Gong Y, Feng S, et al.
    Anal Chem, 2016 06 21;88(12):6254-64.
    PMID: 27012657 DOI: 10.1021/acs.analchem.6b00195
    In nucleic acid testing (NAT), gold nanoparticle (AuNP)-based lateral flow assays (LFAs) have received significant attention due to their cost-effectiveness, rapidity, and the ability to produce a simple colorimetric readout. However, the poor sensitivity of AuNP-based LFAs limits its widespread applications. Even though various efforts have been made to improve the assay sensitivity, most methods are inappropriate for integration into LFA for sample-to-answer NAT at the point-of-care (POC), usually due to the complicated fabrication processes or incompatible chemicals used. To address this, we propose a novel strategy of integrating a simple fluidic control strategy into LFA. The strategy involves incorporating a piece of paper-based shunt and a polydimethylsiloxane (PDMS) barrier to the strip to achieve optimum fluidic delays for LFA signal enhancement, resulting in 10-fold signal enhancement over unmodified LFA. The phenomena of fluidic delay were also evaluated by mathematical simulation, through which we found the movement of fluid throughout the shunt and the tortuosity effects in the presence of PDMS barrier, which significantly affect the detection sensitivity. To demonstrate the potential of integrating this strategy into a LFA with sample-in-answer-out capability, we further applied this strategy into our prototype sample-to-answer LFA to sensitively detect the Hepatitis B virus (HBV) in clinical blood samples. The proposed strategy offers great potential for highly sensitive detection of various targets for wide application in the near future.
  11. Choi JR, Hu J, Gong Y, Feng S, Wan Abas WA, Pingguan-Murphy B, et al.
    Analyst, 2016 05 10;141(10):2930-9.
    PMID: 27010033 DOI: 10.1039/c5an02532j
    Lateral flow assays (LFAs) have been extensively explored in nucleic acid testing (NAT) for medical diagnostics, food safety analysis and environmental monitoring. However, the amount of target nucleic acid in a raw sample is usually too low to be directly detected by LFAs, necessitating the process of amplification. Even though cost-effective paper-based amplification techniques have been introduced, they have always been separately performed from LFAs, hence increasing the risk of reagent loss and cross-contaminations. To date, integrating paper-based nucleic acid amplification into colorimetric LFA in a simple, portable and cost-effective manner has not been introduced. Herein, we developed an integrated LFA with the aid of a specially designed handheld battery-powered system for effective amplification and detection of targets in resource-poor settings. Interestingly, using the integrated paper-based loop-mediated isothermal amplification (LAMP)-LFA, we successfully performed highly sensitive and specific target detection, achieving a detection limit of as low as 3 × 10(3) copies of target DNA, which is comparable to the conventional tube-based LAMP-LFA in an unintegrated format. The device may serve in conjunction with a simple paper-based sample preparation to create a fully integrated paper-based sample-to-answer diagnostic device for point-of-care testing (POCT) in the near future.
  12. Choi JR, Hu J, Wang S, Yang H, Wan Abas WA, Pingguan-Murphy B, et al.
    Crit Rev Biotechnol, 2017 Feb;37(1):100-111.
    PMID: 26912259
    Dengue endemic is a serious healthcare concern in tropical and subtropical countries. Although well-established laboratory tests can provide early diagnosis of acute dengue infections, access to these tests is limited in developing countries, presenting an urgent need to develop simple, rapid, and robust diagnostic tools. Point-of-care (POC) devices, particularly paper-based POC devices, are typically rapid, cost-effective and user-friendly, and they can be used as diagnostic tools for the prompt diagnosis of dengue at POC settings. Here, we review the importance of rapid dengue diagnosis, current dengue diagnostic methods, and the development of paper-based POC devices for diagnosis of dengue infections at the POC.
  13. Choi JR, Hu J, Tang R, Gong Y, Feng S, Ren H, et al.
    Lab Chip, 2016 Feb 7;16(3):611-21.
    PMID: 26759062 DOI: 10.1039/c5lc01388g
    With advances in point-of-care testing (POCT), lateral flow assays (LFAs) have been explored for nucleic acid detection. However, biological samples generally contain complex compositions and low amounts of target nucleic acids, and currently require laborious off-chip nucleic acid extraction and amplification processes (e.g., tube-based extraction and polymerase chain reaction (PCR)) prior to detection. To the best of our knowledge, even though the integration of DNA extraction and amplification into a paper-based biosensor has been reported, a combination of LFA with the aforementioned steps for simple colorimetric readout has not yet been demonstrated. Here, we demonstrate for the first time an integrated paper-based biosensor incorporating nucleic acid extraction, amplification and visual detection or quantification using a smartphone. A handheld battery-powered heating device was specially developed for nucleic acid amplification in POC settings, which is coupled with this simple assay for rapid target detection. The biosensor can successfully detect Escherichia coli (as a model analyte) in spiked drinking water, milk, blood, and spinach with a detection limit of as low as 10-1000 CFU mL(-1), and Streptococcus pneumonia in clinical blood samples, highlighting its potential use in medical diagnostics, food safety analysis and environmental monitoring. As compared to the lengthy conventional assay, which requires more than 5 hours for the entire sample-to-answer process, it takes about 1 hour for our integrated biosensor. The integrated biosensor holds great potential for detection of various target analytes for wide applications in the near future.
  14. Choi JR, Tang R, Wang S, Wan Abas WA, Pingguan-Murphy B, Xu F
    Biosens Bioelectron, 2015 Dec 15;74:427-39.
    PMID: 26164488 DOI: 10.1016/j.bios.2015.06.065
    Nucleic acid testing (NAT), as a molecular diagnostic technique, including nucleic acid extraction, amplification and detection, plays a fundamental role in medical diagnosis for timely medical treatment. However, current NAT technologies require relatively high-end instrumentation, skilled personnel, and are time-consuming. These drawbacks mean conventional NAT becomes impractical in many resource-limited disease-endemic settings, leading to an urgent need to develop a fast and portable NAT diagnostic tool. Paper-based devices are typically robust, cost-effective and user-friendly, holding a great potential for NAT at the point of care. In view of the escalating demand for the low cost diagnostic devices, we highlight the beneficial use of paper as a platform for NAT, the current state of its development, and the existing challenges preventing its widespread use. We suggest a strategy involving integrating all three steps of NAT into one single paper-based sample-to-answer diagnostic device for rapid medical diagnostics in the near future.
  15. Choi JR, Yong KW, Tang R, Gong Y, Wen T, Yang H, et al.
    Adv Healthc Mater, 2017 Jan;6(1).
    PMID: 27860384 DOI: 10.1002/adhm.201600920
    Paper-based devices have been broadly used for the point-of-care detection of dengue viral nucleic acids due to their simplicity, cost-effectiveness, and readily observable colorimetric readout. However, their moderate sensitivity and functionality have limited their applications. Despite the above-mentioned advantages, paper substrates are lacking in their ability to control fluid flow, in contrast to the flow control enabled by polymer substrates (e.g., agarose) with readily tunable pore size and porosity. Herein, taking the benefits from both materials, the authors propose a strategy to create a hybrid substrate by incorporating agarose into the test strip to achieve flow control for optimal biomolecule interactions. As compared to the unmodified test strip, this strategy allows sensitive detection of targets with an approximately tenfold signal improvement. Additionally, the authors showcase the potential of functionality improvement by creating multiple test zones for semi-quantification of targets, suggesting that the number of visible test zones is directly proportional to the target concentration. The authors further demonstrate the potential of their proposed strategy for clinical assessment by applying it to their prototype sample-to-result test strip to sensitively and semi-quantitatively detect dengue viral RNA from the clinical blood samples. This proposed strategy holds significant promise for detecting various targets for diverse future applications.
  16. Chong PP, Panjavarnam P, Ahmad WNHW, Chan CK, Abbas AA, Merican AM, et al.
    Clin Biomech (Bristol, Avon), 2020 10;79:105178.
    PMID: 32988676 DOI: 10.1016/j.clinbiomech.2020.105178
    BACKGROUND: Cartilage damage, which can potentially lead to osteoarthritis, is a leading cause of morbidity in the elderly population. Chondrocytes are sensitive to mechanical stimuli and their matrix-protein synthesis may be altered when chondrocytes experience a variety of in vivo loadings. Therefore, a study was conducted to evaluate the biosynthesis of isolated osteoarthritic chondrocytes which subjected to compression with varying dynamic compressive strains and loading durations.

    METHODS: The proximal tibia was resected as a single osteochondral unit during total knee replacement from patients (N = 10). The osteoarthritic chondrocytes were isolated from the osteochondral units, and characterized using reverse transcriptase-polymerase chain reaction. The isolated osteoarthritic chondrocytes were cultured and embedded in agarose, and then subjected to 10% and 20% uniaxial dynamic compression up to 8-days using a bioreactor. The morphological features and changes in the osteoarthritic chondrocytes upon compression were evaluated using scanning electron microscopy. Safranin O was used to detect the presence of cartilage matrix proteoglycan expression while quantitative analysis was conducted by measuring type VI collagen using an immunohistochemistry and fluorescence intensity assay.

    FINDINGS: Gene expression analysis indicated that the isolated osteoarthritic chondrocytes expressed chondrocyte-specific markers, including BGN, CD90 and HSPG-2. Moreover, the compressed osteoarthritic chondrocytes showed a more intense and broader deposition of proteoglycan and type VI collagen than control. The expression of type VI collagen was directly proportional to the duration of compression in which 8-days compression was significantly higher than 4-days compression. The 20% compression showed significantly higher intensity compared to 10% compression in 4- and 8-days.

    INTERPRETATION: The biosynthetic activity of human chondrocytes from osteoarthritic joints can be enhanced using selected compression regimes.

  17. Chua KH, Raduan F, Wan Safwani WK, Manzor NF, Pingguan-Murphy B, Sathapan S
    Cell Prolif, 2013 Jun;46(3):300-11.
    PMID: 23672290 DOI: 10.1111/cpr.12029
    OBJECTIVES: This study investigated effects of reduced serum condition and vascular endothelial growth factor (VEGF) on angiogenic potential of adipose stromal cells (ASCs) in vitro.

    MATERIALS AND METHODS: Adipose stromal cells were cultured in three different types of medium: (i) F12/DMEM (FD) supplemented with 10% FBS from passage 0 (P0) to P6; (ii) FD supplemented with 2% FBS at P6; and (iii) FD supplemented with 2% FBS plus 50 ng/ml of VEGF at P6. Morphological changes and growth rate of ASCs were recorded. Changes in stemness, angiogenic and endogenic genes' expressions were analysed using Real-Time PCR.

    RESULTS: Adipose stromal cells changed from fibroblast-like shape when cultured in 10% FBS medium to polygonal when cultured in 2% FBS plus VEGF-supplemented medium. Their growth rate was lower in 2% FBS medium, but increased with addition of VEGF. Real-Time PCR showed that ASCs maintained most of their stemness and angiogenic genes' expression in 10% FBS at P1, P5 and P6, but this increased significantly in 2% FBS at P6. Endogenic genes expression such as PECAM-1, VE chaderin and VEGFR-2 decreased after serial passage in 10% FBS, but increased significantly at P6 in 2% FBS. Addition of VEGF did not cause any significant change in gene expression level.

    CONCLUSION: Adipose stromal cells had greater angiogenic potential when cultured in reduced serum conditions. VEGF did not enhance their angiogenic potential in 2% FBS-supplemented medium.

  18. Ewa-Choy YW, Pingguan-Murphy B, Abdul-Ghani NA, Jahendran J, Chua KH
    Biomater Res, 2017;21:19.
    PMID: 29075508 DOI: 10.1186/s40824-017-0105-7
    BACKGROUND: The three-dimensional (3D) system is one of the important factors to engineer a biocompatible and functional scaffold for the applications of cell-based therapies for cartilage repair. The 3D alginate hydrogels system has previously been shown to potentially promote chondrogenesis. The chondrocytic differentiation of co-cultured adipose-derived stem cells (ADSCs) and nasal chondrocytes (NCs) within alginate constructs are hypothesized to be influenced by concentration of alginate hydrogel. In this study, we evaluated the effects of alginate concentration on chondrogenic differentiation of ADSCs and NCs co-cultured in a biological approach.

    METHOD: The co-cultured cells of 2:1 ADSCs-to-NCs ratio were encapsulated in alginate constructs in one of three concentrations (1.0%, 1.2% and 1.5%) and cultured under serum free conditions for 7 days. Cell viability, cell proliferation, immunohistochemical, gycosaminogylycans (GAG) synthesis, and gene expression were examined.

    RESULTS: Overall, the 1.2% alginate concentration group was relatively effective in chondrocytic differentiation in comparable to other groups. The cell morphology, cell viability, and cell proliferation revealed initial chondrogenic differentiation by the formation of cell clusters as well as the high permeability for exchange of solutes. The formation of newly synthesis cartilage-specific extracellular matrix in 1.2% group was demonstrated by positive immunohistochemical staining of collagen type II. The co-cultured cells in 1.2% group highly expressed COL II, ACP and SOX-9, compared to 1.0% and 1.5% groups, denote the retention of cartilaginous-specific phenotype by suppressing the undifferentiation stem cell markers of SOX-2 and OCT-4. The study showed 1.2% group was less likely to differentiate towards osteogenesis by downregulating hyperthrophy chondrocytic gene of COL X and osseous marker genes of OSC and OSP.

    CONCLUSION: This study suggests that variations in the alginate concentration of co-cultured ADSCs and NCs influenced the chondrogenesis. The remarkable biological performance on chondrogenic differentiation in regulating the concentration of alginate 3D culture provides new insights into the cell cross-talk and demonstrates the effectiveness in regenerative therapies of cartilage defects in tissue engineering.

  19. Gao B, Wang L, Han S, Pingguan-Murphy B, Zhang X, Xu F
    Crit Rev Biotechnol, 2016 Aug;36(4):619-29.
    PMID: 25669871 DOI: 10.3109/07388551.2014.1002381
    Diabetes now is the most common chronic disease in the world inducing heavy burden for the people's health. Based on this, diabetes research such as islet function has become a hot topic in medical institutes of the world. Today, in medical institutes, the conventional experiment platform in vitro is monolayer cell culture. However, with the development of micro- and nano-technologies, several microengineering methods have been developed to fabricate three-dimensional (3D) islet models in vitro which can better mimic the islet of pancreases in vivo. These in vitro islet models have shown better cell function than monolayer cells, indicating their great potential as better experimental platforms to elucidate islet behaviors under both physiological and pathological conditions, such as the molecular mechanisms of diabetes and clinical islet transplantation. In this review, we present the state-of-the-art advances in the microengineering methods for fabricating microscale islet models in vitro. We hope this will help researchers to better understand the progress in the engineering 3D islet models and their biomedical applications such as drug screening and islet transplantation.
  20. Ghosh S, Choudhury D, Roy T, Moradi A, Masjuki HH, Pingguan-Murphy B
    Sci Technol Adv Mater, 2015 Aug;16(4):045002.
    PMID: 27877822
    The concentration of biological components of synovial fluid (such as albumin, globulin, hyaluronic acid, and lubricin) varies between healthy persons and osteoarthritis (OA) patients. The aim of the present study is to compare the effects of such variation on tribological performance in a simulated hip joint model. The study was carried out experimentally by utilizing a pin-on-disk simulator on ceramic-on-ceramic (CoC) and ceramic-on-polyethylene (CoP) hip joint implants. The experimental results show that both friction and wear of artificial joints fluctuate with the concentration level of biological components. Moreover, the performance also varies between material combinations. Wear debris sizes and shapes produced by ceramic and polyethylene were diverse. We conclude that the biological components of synovial fluid and their concentrations should be considered in order to select an artificial hip joint to best suit that patient.
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