Displaying publications 61 - 80 of 84 in total

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  1. Rosli NA, Karamanlioglu M, Kargarzadeh H, Ahmad I
    Int J Biol Macromol, 2021 Sep 30;187:732-741.
    PMID: 34358596 DOI: 10.1016/j.ijbiomac.2021.07.196
    Poly(lactic acid) (PLA), a bio-based polyester, has been extensively investigated in the recent past owing to its excellent mechanical properties. Several studies have been conducted on PLA blends, with a focus on improving the brittleness of PLA to ensure its suitability for various applications. However, the increasing use of PLA has increased the contamination of PLA-based products in the environment because PLA remains intact even after three years at sea or in soil. This review focuses on analyzing studies that have worked on improving the degradation properties of PLA blends and studies how other additives affect degradation by considering different degradation media. Factors affecting the degradation properties, such as surface morphology, water uptake, and crystallinity of PLA blends, are highlighted. In natural, biotic, and abiotic media, water uptake plays a crucial role in determining biodegradation rates. Immiscible blends of PLA with other polymer matrices cause phase separation, increasing the water absorption. The susceptibility of PLA to hydrolytic and enzymatic degradation is high in the amorphous region because it can be easily penetrated by water. It is essential to study the morphology, water absorption, and structural properties of PLA blends to predict the biodegradation properties of PLA in the blends.
    Matched MeSH terms: Polyesters/chemistry*
  2. Rozila I, Azari P, Munirah S, Wan Safwani WK, Gan SN, Nur Azurah AG, et al.
    J Biomed Mater Res A, 2016 Feb;104(2):377-87.
    PMID: 26414782 DOI: 10.1002/jbm.a.35573
    The osteogenic potential of human adipose-derived stem cells (HADSCs) co-cultured with human osteoblasts (HOBs) using selected HADSCs/HOBs ratios of 1:1, 2:1, and 1:2, respectively, is evaluated. The HADSCs/HOBs were seeded on electrospun three-dimensional poly[(R)-3-hydroxybutyric acid] (PHB) blended with bovine-derived hydroxyapatite (BHA). Monocultures of HADSCs and HOBs were used as control groups. The effects of PHB-BHA scaffold on cell proliferation and cell morphology were assessed by AlamarBlue assay and field emission scanning electron microscopy. Cell differentiation, cell mineralization, and osteogenic-related gene expression of co-culture HADSCs/HOBs were examined by alkaline phosphatase (ALP) assay, alizarin Red S assay, and quantitative real time PCR, respectively. The results showed that co-culture of HADSCs/HOBs, 1:1 grown into PHB-BHA promoted better cell adhesion, displayed a significant higher cell proliferation, higher production of ALP, extracellular mineralization and osteogenic-related gene expression of run-related transcription factor, bone sialoprotein, osteopontin, and osteocalcin compared to other co-culture groups. This result also suggests that the use of electrospun PHB-BHA in a co-culture HADSCs/HOBs system may serve as promising approach to facilitate osteogenic differentiation activity of HADSCs through direct cell-to-cell contact with HOBs.
    Matched MeSH terms: Polyesters/chemistry*
  3. Saika A, Watanabe Y, Sudesh K, Tsuge T
    J Biosci Bioeng, 2014 Jun;117(6):670-5.
    PMID: 24484910 DOI: 10.1016/j.jbiosc.2013.12.006
    An obligate anaerobic bacterium Clostridium difficile has a unique metabolic pathway to convert leucine to 4-methylvalerate, in which 4-methyl-2-pentenoyl-CoA (4M2PE-CoA) is an intermediate of this pathway. 4M2PE-CoA is also able to be converted to 3-hydroxy-4-methylvalerate (3H4MV), a branched side chain monomer unit, for synthesis of polyhydroxyalkanoate (PHA) copolymer. In this study, to synthesize 3H4MV-containing PHA copolymer from leucine, the leucine metabolism-related enzymes (LdhA and HadAIBC) derived from C. difficile and PHA biosynthesis enzymes (PhaPCJAc and PhaABRe) derived from Aeromonas caviae and Ralstonia eutropha were co-expressed in the codon usage-improved Escherichia coli. Under microaerobic culture conditions, this E. coli was able to synthesize P(3HB-co-12.2 mol% 3H4MV) from glucose with the supplementation of 1 g/L leucine. This strain also produced P(3HB-co-12.6 mol% 3H4MV) using the culture supernatant of leucine overproducer E. coli strain NS1391 as the medium for PHA production, achieving 3H4MV copolymer synthesis only from glucose. Furthermore, we tested the feasibility of the 3H4MV copolymer synthesis in E. coli strain NS1391 from glucose. The recombinant E. coli NS1391 was able to synthesize P(3HB-co-3.0 mol% 3H4MV) from glucose without any leucine supplementation. This study demonstrates the potential of the new metabolic pathway for 3H4MV synthesis using leucine metabolism-related enzymes from C. difficile.
    Matched MeSH terms: Polyesters/chemistry
  4. Samrot AV, Sean TC, Kudaiyappan T, Bisyarah U, Mirarmandi A, Faradjeva E, et al.
    Int J Biol Macromol, 2020 Dec 15;165(Pt B):3088-3105.
    PMID: 33098896 DOI: 10.1016/j.ijbiomac.2020.10.104
    Chitosan, collagen, gelatin, polylactic acid and polyhydroxyalkanoates are notable examples of biopolymers, which are essentially bio-derived polymers produced by living cells. With the right techniques, these biological macromolecules can be exploited for nanotechnological advents, including for the fabrication of nanocarriers. In the world of nanotechnology, it is highly essential (and optimal) for nanocarriers to be biocompatible, biodegradable and non-toxic for safe in vivo applications, including for drug delivery, cancer immunotherapy, tissue engineering, gene delivery, photodynamic therapy and many more. The recent advancements in understanding nanotechnology and the physicochemical properties of biopolymers allows us to modify biological macromolecules and use them in a multitude of fields, most notably for clinical and therapeutic applications. By utilizing chitosan, collagen, gelatin, polylactic acid, polyhydroxyalkanoates and various other biopolymers as synthesis ingredients, the 'optimal' properties of a nanocarrier can easily be attained. With emphasis on the aforementioned biological macromolecules, this review presents the various biopolymers utilized for nanocarrier synthesis along with their specific synthetization methods. We further discussed on the characterization techniques and related applications for the synthesized nanocarriers.
    Matched MeSH terms: Polyesters/chemistry*
  5. Samsudin H, Auras R, Burgess G, Dolan K, Soto-Valdez H
    Food Res Int, 2018 03;105:920-929.
    PMID: 29433289 DOI: 10.1016/j.foodres.2017.11.065
    A two-step solution based on the boundary conditions of Crank's equations for mass transfer in a film was developed. Three driving factors, the diffusion (D), partition (Kp,f) and convective mass transfer coefficients (h), govern the sorption and/or desorption kinetics of migrants from polymer films. These three parameters were simultaneously estimated. They provide in-depth insight into the physics of a migration process. The first step was used to find the combination of D, Kp,f and h that minimized the sums of squared errors (SSE) between the predicted and actual results. In step 2, an ordinary least square (OLS) estimation was performed by using the proposed analytical solution containing D, Kp,f and h. Three selected migration studies of PLA/antioxidant-based films were used to demonstrate the use of this two-step solution. Additional parameter estimation approaches such as sequential and bootstrap were also performed to acquire a better knowledge about the kinetics of migration. The proposed model successfully provided the initial guesses for D, Kp,f and h. The h value was determined without performing a specific experiment for it. By determining h together with D, under or overestimation issues pertaining to a migration process can be avoided since these two parameters are correlated.
    Matched MeSH terms: Polyesters/chemistry*
  6. Sanyang ML, Sapuan SM, Jawaid M, Ishak MR, Sahari J
    Carbohydr Polym, 2016 08 01;146:36-45.
    PMID: 27112848 DOI: 10.1016/j.carbpol.2016.03.051
    The development and characterization of environmentally friendly bilayer films from sugar palm starch (SPS) and poly(lactic acid) (PLA) were conducted in this study. The SPS-PLA bilayer films and their individual components were characterized for their physical, mechanical, thermal and water barrier properties. Addition of 50% PLA layer onto 50% SPS layer (SPS50-PLA50) increased the tensile strength of neat SPS film from 7.74 to 13.65MPa but reduced their elongation at break from 46.66 to 15.53%. The incorporation of PLA layer significantly reduced the water vapor permeability as well as the water uptake and solubility of bilayer films which was attributed to the hydrophobic characteristic of the PLA layer. Furthermore, scanning electron microscopy (SEM) image of SPS50-PLA50 revealed lack of strong interfacial adhesion between the SPS and PLA. Overall, the incorporation of PLA layer onto SPS films enhances the suitability of SPS based films for food packaging.
    Matched MeSH terms: Polyesters/chemistry*
  7. Sayyed RZ, Wani SJ, Alarfaj AA, Syed A, El-Enshasy HA
    PLoS One, 2020;15(1):e0220095.
    PMID: 31910206 DOI: 10.1371/journal.pone.0220095
    There are numerous reports on poly-β-hydroxybutyrate (PHB) depolymerases produced by various microorganisms isolated from various habitats, however, reports on PHB depolymerase production by an isolate from plastic rich sites scares. Although PHB has attracted commercial significance, the inefficient production and recovery methods, inefficient purification of PHB depolymerase and lack of ample knowledge on PHB degradation by PHB depolymerase have hampered its large scale commercialization. Therefore, to ensure the biodegradability of biopolymers, it becomes imperative to study the purification of the biodegrading enzyme system. We report the production, purification, and characterization of extracellular PHB depolymerase from Stenotrophomonas sp. RZS7 isolated from a dumping yard rich in plastic waste. The isolate produced extracellular PHB depolymerase in the mineral salt medium (MSM) at 30°C during 4 days of incubation under shaking. The enzyme was purified by three methods namely ammonium salt precipitation, column chromatography, and solvent purification. Among these purification methods, the enzyme was best purified by column chromatography on the Octyl-Sepharose CL-4B column giving optimum yield (0.7993 Umg-1mL-1). The molecular weight of purified PHB depolymerase was 40 kDa. Studies on the assessment of biodegradation of PHB in liquid culture medium and under natural soil conditions confirmed PHB biodegradation potential of Stenotrophomonas sp. RZS7. The results obtained in Fourier-Transform Infrared (FTIR) analysis, High-Performance Liquid Chromatography (HPLC) study and Gas Chromatography Mass-Spectrometry (GC-MS) analysis confirmed the biodegradation of PHB in liquid medium by Stenotrophomonas sp. RZS7. Changes in surface morphology of PHB film in soil burial as observed in Field Emission Scanning Electron Microscopy (FESEM) analysis confirmed the biodegradation of PHB under natural soil environment. The isolate was capable of degrading PHB and it resulted in 87.74% biodegradation. A higher rate of degradation under the natural soil condition is the result of the activity of soil microbes that complemented the biodegradation of PHB by Stenotrophomonas sp. RZS7.
    Matched MeSH terms: Polyesters/chemistry*
  8. Selvakumar M, Srivastava P, Pawar HS, Francis NK, Das B, Sathishkumar G, et al.
    ACS Appl Mater Interfaces, 2016 Feb 17;8(6):4086-100.
    PMID: 26799576 DOI: 10.1021/acsami.5b11723
    Guided bone regeneration (GBR) scaffolds are futile in many clinical applications due to infection problems. In this work, we fabricated GBR with an anti-infective scaffold by ornamenting 2D single crystalline bismuth-doped nanohydroxyapatite (Bi-nHA) rods onto segmented polyurethane (SPU). Bi-nHA with high aspect ratio was prepared without any templates. Subsequently, it was introduced into an unprecedented synthesized SPU matrix based on dual soft segments (PCL-b-PDMS) of poly(ε-caprolactone) (PCL) and poly(dimethylsiloxane) (PDMS), by an in situ technique followed by electrospinning to fabricate scaffolds. For comparison, undoped pristine nHA rods were also ornamented into it. The enzymatic ring-opening polymerization technique was adapted to synthesize soft segments of PCL-b-PDMS copolymers of SPU. Structure elucidation of the synthesized polymers is done by nuclear magnetic resonance spectroscopy. Sparingly, Bi-nHA ornamented scaffolds exhibit tremendous improvement (155%) in the mechanical properties with excellent antimicrobial activity against various human pathogens. After confirmation of high osteoconductivity, improved biodegradation, and excellent biocompatibility against osteoblast cells (in vitro), the scaffolds were implanted in rabbits by subcutaneous and intraosseous (tibial) sites. Various histological sections reveal the signatures of early cartilage formation, endochondral ossification, and rapid bone healing at 4 weeks of the critical defects filled with ornamented scaffold compared to SPU scaffold. This implies osteogenic potential and ability to provide an adequate biomimetic microenvironment for mineralization for GBR of the scaffolds. Organ toxicity studies further confirm that no tissue architecture abnormalities were observed in hepatic, cardiac, and renal tissue sections. This finding manifests the feasibility of fabricating a mechanically adequate nanofibrous SPU scaffold by a biomimetic strategy and the advantages of Bi-nHA ornamentation in promoting osteoblast phenotype progression with microbial protection (on-demand) for GBR applications.
    Matched MeSH terms: Polyesters/chemistry
  9. Siew EL, Rajab NF, Osman AB, Sudesh K, Inayat-Hussain SH
    J Biomed Mater Res A, 2009 Dec;91(3):786-94.
    PMID: 19051306 DOI: 10.1002/jbm.a.32290
    Polyhydroxyalkanoates (PHA) are naturally occurring biopolyesters that have great potential in the medical field. However, the leachables resulting from sterilization process of the biomaterials may exert toxic effect including genetic damage. Here, we demonstrate that although gamma-irradiation of poly(3-hydroxybutyrate-co-50 mol % 4-hydroxybutyrate) [P(3HB-co-4HB)] did not cause any change in the morphology by scanning electron microscopy, there was a significant degradation of this copolymer where the molecular weight was reduced by 37% after sterilization indicating the generation of leachables. Therefore, further investigation on the ability of the extract of this poststerilized copolymer to induce mutagenic effect was performed using Ames test (S. typhimurium strains TA1535 and TA1537) and umu test (S. typhimurium strain TA1535/pSK1002). Additionally, the capability of the extract to induce clastogenic effect was determined using Chinese hamster lung V79 fibroblast cells. Our results showed that with and without the presence of S9 metabolic activation, no mutagenic effects were observed in both Ames and umu tests when treated with P(3HB-co-4HB) extract. Similarly, treatment of P(3HB-co-4HB) extract in V79 fibroblast cells showed no significant production of micronuclei when compared with the positive control (Mitomycin C). Together, these results indicate that leachables of poststerilized P(3HB-co-4HB) cause no mutagenic and clastogenic effects.
    Matched MeSH terms: Polyesters/chemistry*
  10. Siyamak S, Ibrahim NA, Abdolmohammadi S, Yunus WM, Rahman MZ
    Molecules, 2012 Feb 16;17(2):1969-91.
    PMID: 22343368 DOI: 10.3390/molecules17021969
    In this work, the oil palm empty fruit bunch (EFB) fiber was used as a source of lignocellulosic filler to fabricate a novel type of cost effective biodegradable composite, based on the aliphatic aromatic co-polyester poly(butylene adipate-co-terephtalate) PBAT (Ecoflex™), as a fully biodegradable thermoplastic polymer matrix. The aim of this research was to improve the new biocomposites' performance by chemical modification using succinic anhydride (SAH) as a coupling agent in the presence and absence of dicumyl peroxide (DCP) and benzoyl peroxide (BPO) as initiators. For the composite preparation, several blends were prepared with varying ratios of filler and matrix using the melt blending technique. The composites were prepared at various fiber contents of 10, 20, 30, 40 and 50 (wt %) and characterized. The effects of fiber loading and coupling agent loading on the thermal properties of biodegradable polymer composites were evaluated using thermal gravimetric analysis (TGA). Scanning Electron Microscopy (SEM) was used for morphological studies. The chemical structure of the new biocomposites was also analyzed using the Fourier Transform Infrared (FTIR) spectroscopy technique. The PBAT biocomposite reinforced with 40 (wt %) of EFB fiber showed the best mechanical properties compared to the other PBAT/EFB fiber biocomposites. Biocomposite treatment with 4 (wt %) succinic anhydride (SAH) and 1 (wt %) dicumyl peroxide (DCP) improved both tensile and flexural strength as well as tensile and flexural modulus. The FTIR analyses proved the mechanical test results by presenting the evidence of successful esterification using SAH/DCP in the biocomposites' spectra. The SEM micrograph of the tensile fractured surfaces showed the improvement of fiber-matrix adhesion after using SAH. The TGA results showed that chemical modification using SAH/DCP improved the thermal stability of the PBAT/EFB biocomposite.
    Matched MeSH terms: Polyesters/chemistry*
  11. Siyamak S, Ibrahim NA, Abdolmohammadi S, Yunus WM, Rahman MZ
    Int J Mol Sci, 2012;13(2):1327-46.
    PMID: 22408394 DOI: 10.3390/ijms13021327
    A new class of biocomposites based on oil palm empty fruit bunch fiber and poly(butylene adipate-co-terephthalate) (PBAT), which is a biodegradable aliphatic aromatic co-polyester, were prepared using melt blending technique. The composites were prepared at various fiber contents of 10, 20, 30, 40 and 50 wt% and characterized. Chemical treatment of oil palm empty fruit bunch (EFB) fiber was successfully done by grafting succinic anhydride (SAH) onto the EFB fiber surface, and the modified fibers were obtained in two levels of grafting (low and high weight percentage gain, WPG) after 5 and 6 h of grafting. The FTIR characterization showed evidence of successful fiber esterification. The results showed that 40 wt% of fiber loading improved the tensile properties of the biocomposite. The effects of EFB fiber chemical treatments and various organic initiators content on mechanical and thermal properties and water absorption of PBAT/EFB 60/40 wt% biocomposites were also examined. The SAH-g-EFB fiber at low WPG in presence of 1 wt% of dicumyl peroxide (DCP) initiator was found to significantly enhance the tensile and flexural properties as well as water resistance of biocomposite (up to 24%) compared with those of untreated fiber reinforced composites. The thermal behavior of the composites was evaluated from thermogravimetric analysis (TGA)/differential thermogravimetric (DTG) thermograms. It was observed that, the chemical treatment has marginally improved the biocomposites' thermal stability in presence of 1 wt% of dicumyl peroxide at the low WPG level of grafting. The improved fiber-matrix surface enhancement in the chemically treated biocomposite was confirmed by SEM analysis of the tensile fractured specimens.
    Matched MeSH terms: Polyesters/chemistry*
  12. Sologashvili T, Saat SA, Tille JC, De Valence S, Mugnai D, Giliberto JP, et al.
    Eur J Pharm Biopharm, 2019 Jun;139:272-278.
    PMID: 31004790 DOI: 10.1016/j.ejpb.2019.04.012
    OBJECTIVE: Vascular prostheses for small caliber bypass grafts in cardiac and vascular diseases or for access surgery are still missing. Poly (Ɛ-caprolactone) (PCL) has been previously investigated by our group and showed good biocompatibility and mechanical properties in vitro and rapid endothelialisation, cellular infiltration and vascularisation in vivo yielding optimal patency in the abdominal aortic position. The aim of the present study is to evaluate our PCL graft in the carotid position and to compare its outcome to the grafts implanted in the abdominal aortic position.

    METHODS: PCL grafts (1 mm ID/10 mm long) were implanted into the left common carotid artery in 20 Sprague-Dawley rats and compared to our previously published series of abdominal aortic implants. The animals were followed up to 3, 6, 12 and 24 weeks. At each time point, in vivo compliance, angiography and histological examination with morphology were performed.

    RESULTS: PCL grafts showed good mechanical properties and ease of handling. The average graft compliance was 14.5 ± 1.7%/ mmHg compared to 7.8 ± 0.9% for the abdominal position and 45.1 ± 3.2%/ mmHg for the native carotid artery. The overall patency for the carotid position was 65% as compared to 100% in the abdominal position. Complete endothelialisation was achieved at 3 weeks and cell invasion was more rapid than in the aortic position. In contrast, intimal hyperplasia (IH) and vascular density were less pronounced than in the aortic position.

    CONCLUSION: Our PCL grafts in the carotid position were well endothelialised with early cellular infiltration, higher compliance, lower IH and calcification compared to the similar grafts implanted in the aortic position. However, there was a higher occlusion rate compared to our abdominal aorta series. Anatomical position, compliance mismatch, flow conditions may answer the difference in patency seen.

    Matched MeSH terms: Polyesters/chemistry
  13. Sucinda EF, Abdul Majid MS, Ridzuan MJM, Cheng EM, Alshahrani HA, Mamat N
    Int J Biol Macromol, 2021 Sep 30;187:43-53.
    PMID: 34271052 DOI: 10.1016/j.ijbiomac.2021.07.069
    A packaging material that is environment-friendly with excellent mechanical and physicochemical properties, biodegradable and ultraviolet (UV) protection and thermal stability was prepared to reduce plastic waste. Six different concentrations of Pennisetum purpureum/Napier cellulose nanowhiskers (NWCs) (i.e. 0, 0.5, 1.0, 1.5, 2.0, and 3.0 wt%) were used to reinforce polylactic acid (PLA) by a solvent casting method. The resulting bionanocomposite film samples were characterised in terms of their morphology, chemical structure, crystallinity, thermal degradation and stability, light transmittance, water absorption, biodegradability, and physical and mechanical properties. Field-emission scanning electron microscopy showed the excellent dispersion of NWC in the PLA matrix occurred with NWC concentrations of 0.5-1.5 wt%. All the bionanocomposite film samples exhibited good thermal stability at approximately 343-359 °C. The highest water absorption was 1.94%. The lowest transparency at λ800 was 16.16% for the PLA/3.0% NWC bionanocomposite film, which also has the lowest UVA and UVB transmittance of 7.49% and 4.02%, respectively, making it suitable for packaging materials. The PLA/1.0% NWC film exhibited the highest crystallinity of 50.09% and high tensile strength and tensile modulus of 21.22 MPa and 11.35 MPa, respectively.
    Matched MeSH terms: Polyesters/chemistry*
  14. Syafiq IM, Huong KH, Shantini K, Vigneswari S, Aziz NA, Amirul AA, et al.
    Enzyme Microb Technol, 2017 Mar;98:1-8.
    PMID: 28110659 DOI: 10.1016/j.enzmictec.2016.11.011
    Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] copolymer is noted for its high biocompatibility, which makes it an excellent candidate for biopharmaceutical applications. The wild-type Cupriavidus sp. USMAA1020 strain is able to synthesize P(3HB-co-4HB) copolymers with different 4HB monomer compositions (up to 70mol%) in shaken flask cultures. Combinations of 4HB carbon precursors consisting of 1,6-hexanediol and γ-butyrolactone were applied for the production of P(3HB-co-4HB) with different 4HB molar fraction. A sharp increase in 4HB monomer composition was attained by introducing additional copies of PHA synthase gene (phaC), responsible for P(3HB-co-4HB) polymerization. The phaC of Cupriavidus sp. USMAA1020 and Cupriavidus sp. USMAA2-4 were cloned and heterologously introduced into host, wild-type Cupriavidus sp. USMAA1020. The gene dosage treatment resulted in the accumulation of 93mol% 4HB by the transformant strains when grown in similar conditions as the wild-type USMAA1020. The PHA synthase activities for both transformants were almost two-fold higher than the wild-type. The ability of the transformants to produce copolymers with high 4HB monomer composition was also tested in large scale production system using 5L and 30L bioreactors with a constant oxygen mass transfer rate. The 4HB monomer composition could be maintained at a range of 83-89mol%. The mechanical and thermal properties of copolymers improved with increasing 4HB monomer composition. The copolymers produced could be tailored for specific biopharmaceutical applications based on their properties.
    Matched MeSH terms: Polyesters/chemistry
  15. Touri M, Moztarzadeh F, Osman NAA, Dehghan MM, Mozafari M
    Mater Sci Eng C Mater Biol Appl, 2018 Mar 01;84:236-242.
    PMID: 29519434 DOI: 10.1016/j.msec.2017.11.037
    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.
    Matched MeSH terms: Polyesters/chemistry
  16. Trakunjae C, Boondaeng A, Apiwatanapiwat W, Kosugi A, Arai T, Sudesh K, et al.
    Sci Rep, 2021 01 21;11(1):1896.
    PMID: 33479335 DOI: 10.1038/s41598-021-81386-2
    Poly-β-hydroxybutyrate (PHB) is a biodegradable polymer, synthesized as carbon and energy reserve by bacteria and archaea. To the best of our knowledge, this is the first report on PHB production by a rare actinomycete species, Rhodococcus pyridinivorans BSRT1-1. Response surface methodology (RSM) employing central composite design, was applied to enhance PHB production in a flask scale. A maximum yield of 3.6 ± 0.5 g/L in biomass and 43.1 ± 0.5 wt% of dry cell weight (DCW) of PHB were obtained when using RSM optimized medium, which was improved the production of biomass and PHB content by 2.5 and 2.3-fold, respectively. The optimized medium was applied to upscale PHB production in a 10 L stirred-tank bioreactor, maximum biomass of 5.2 ± 0.5 g/L, and PHB content of 46.8 ± 2 wt% DCW were achieved. Furthermore, the FTIR and 1H NMR results confirmed the polymer as PHB. DSC and TGA analysis results revealed the melting, glass transition, and thermal decomposition temperature of 171.8, 4.03, and 288 °C, respectively. In conclusion, RSM can be a promising technique to improve PHB production by a newly isolated strain of R. pyridinivorans BSRT1-1 and the properties of produced PHB possessed similar properties compared to commercial PHB.
    Matched MeSH terms: Polyesters/chemistry*
  17. Vigneswari S, Murugaiyah V, Kaur G, Abdul Khalil HPS, Amirul AA
    Mater Sci Eng C Mater Biol Appl, 2016 Sep 01;66:147-155.
    PMID: 27207048 DOI: 10.1016/j.msec.2016.03.102
    The main focus of this study is the incorporation of collagen peptides to fabricate P(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] nano-fiber construct to further enhance surface wettability and support cell growth while harbouring desired properties for biodegradable wound dressing. Simultaneous electrospinning of nanofiber P(3HB-co-4HB)/collagen peptides construct was carried out using dual syringe system. The wettability of the constructs increased with the increase in 4HB molar fraction from 20mol% 4HB [53.2°], P(3HB-co-35mol%4HB)[48.9°], P(3HB-co-50mol%4HB)[44.5°] and P(3HB-co-82mol%4HB) [37.7°]. In vitro study carried out using mouse fibroblast cells (L929) grown on nanofiber P(3HB-co-4HB)/collagen peptides construct showed an increase in cell proliferation. In vivo study using animal model (Sprague Dawley rats) showed that nanofibrous P(3HB-co-4HB)/collagen peptides construct had a significant effect on wound contractions with the highest percentage of wound closure of 79%. Hence, P(3HB-co-4HB)/collagen peptides construct suitable for wound dressing have been developed using nano-fabrication technique.
    Matched MeSH terms: Polyesters/chemistry*
  18. Vigneswari S, Vijaya S, Majid MI, Sudesh K, Sipaut CS, Azizan MN, et al.
    J Ind Microbiol Biotechnol, 2009 Apr;36(4):547-56.
    PMID: 19189144 DOI: 10.1007/s10295-009-0525-z
    Cupriavidus sp. USMAA1020, a local isolate was able to biosynthesis poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] copolymer with various 4HB precursors as the sole carbon source. Manipulation of the culture conditions such as cell concentration, phosphate ratio and culture aeration significantly affected the synthesis of P(3HB-co-4HB) copolymer and 4HB composition. P(3HB-co-4HB) copolymer with 4HB compositions ranging from 23 to 75 mol% 4HB with various mechanical and thermal properties were successfully produced by varying the medium aeration. The physical and mechanical properties of P(3HB-co-4HB) copolymers were characterized by NMR spectroscopy, gel-permeation chromatography, tensile test, and differential scanning calorimetry. The number-average molecular weights (M (n)) of copolymers ranged from 260 x 10(3) to 590 x 10(3)Da, and the polydispersities (M (w)/M (n)) were between 1.8 and 3.0. Increases in the 4HB composition lowered the molecular weight of these copolymers. In addition, the increase in 4HB composition affected the randomness of copolymer, melting temperature (T (m)), glass transition temperature (T (g)), tensile strength, and elongation to break. Enzymatic degradation of P(3HB-co-4HB) films with an extracellular depolymerase from Ochrobactrum sp. DP5 showed that the degradation rate increased proportionally with time as the 4HB fraction increased from 17 to 50 mol% but were much lower with higher 4HB fraction. Degradation of P(3HB-co-4HB) films with lipase from Chromobacterium viscosum exhibited highest degradation rate at 75 mol% 4HB. The biocompatibility of P(3HB-co-4HB) copolymers were evaluated and these copolymers have been shown to support the growth and proliferation of fibroblast cells.
    Matched MeSH terms: Polyesters/chemistry*
  19. Vigneswari S, Murugaiyah V, Kaur G, Abdul Khalil HP, Amirul AA
    Biomed Mater, 2016 10 06;11(5):055009.
    PMID: 27710927
    Polyhydroxyalkanoate (PHA) is a microbial polymer that has been at the forefront of many attempts at tissue engineering. However, the surface of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB-co-4HB)) is hydrophobic with few recognition sites for cell attachment. Various concentrations of fish-scale collagen peptides (FSCPs) were incorporated into P(3HB-co-4HB) copolymer by aminolysis. Later, FSCPs were introduced onto the aminolyzed P(3HB-co-4HB) scaffolds. Introduction of the FSCP groups was verified using Fourier transform infrared spectroscopy and the ninhydrin method. The effect of the incorporation of FSCPs on hydrophilicity was investigated using the water contact angle. As the concentration of FSCPs increased, the water contact angle decreased. In vitro study demonstrated that P(3HB-co-4HB)/FSCP scaffolds provided better cell attachment and growth of L929 mouse fibroblast cells and better cell proliferation. In vivo study showed that P(3HB-co-4HB)/1.5 wt% FSCPs had a significant effect on wound contractions, with the highest percentage of wound closure (61%) in 7 d.
    Matched MeSH terms: Polyesters/chemistry*
  20. Vijayan V, Shalini K, Yugesvaran V, Yee TH, Balakrishnan S, Palanimuthu VR
    Curr Pharm Des, 2018;24(28):3366-3375.
    PMID: 30179118 DOI: 10.2174/1381612824666180903110301
    BACKGROUND: Triple-Negative Breast Cancer is an aggressive type of breast cancer, which is not treatable by chemotherapy drugs, due to the lack of Estrogen Receptor (ER), Progesterone Receptor (PR) expression and Human Epidermal Growth Factor Receptor 2 (HER2) on the cell surface.

    OBJECTIVE: The aim of this study was to compare the effect of paclitaxel loaded PLGA nanoparticle (PTX-NPs) on the cytotoxicity and apoptosis of the different MDA-MB type of cell lines.

    METHOD: PTX-NPs were prepared by nanoprecipitation method and characterized earlier. The cytotoxicity of PTX-NPs was evaluated by MTT and LDH assay, later apoptosis was calculated by flow cytometry analysis.

    RESULTS: The prepared NP size of 317.5 nm and zetapontial of -12.7 mV showed drug release of 89.1 % at 48 h. MDA-MB-231 type cell showed significant cytotoxicity by MTT method of 47.4 ± 1.2 % at 24 h, 34.6 ± 0.8 % at 48 h and 23.5 ± 0.5 % at 72 h and LDH method of 35.9 ± 1.5 % at 24 h, 25.4 ± 0.6 % at 48 h and 19.8 ± 2.2 % at 72 h with apoptosis of 47.3 ± 0.4 %.

    CONCLUSION: We have found that PTX-NPs showed the cytotoxic effect on all the MDA-MB cancer cell lines and showed potent anticancer activities against MDA-MB-231 cell line via induction of apoptosis.

    Matched MeSH terms: Polyesters/chemistry*
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