Displaying publications 41 - 60 of 374 in total

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  1. Bioactivity and mechanical stability of Ti-6Al-4V implants superplastically embedded with hydroxyapatite in rats
    Mohd Khalid H, Jauhari I, Mohamad Wali HA, Abdulrazzaq Mahmod S
    Biomed Mater, 2017 01 25;12(1):015019.
    PMID: 28120816 DOI: 10.1088/1748-605X/aa4f8b
    In this in vivo study, Sprague Dawley (SD) rats were used to investigate the bioactivity as well as the microstructural and mechanical properties of Ti-6Al-4V samples embedded with hydroxyapatite (HA) using two different coating methods-superplastic embedment (SPE) and superplastic deformation (SPD). The HA layer thickness for the SPE and SPD samples increased from 249.1  ±  0.6 nm to 874.8  ±  13.7 nm, and from 206.1  ±  5.8 nm to 1162.7  ±  7.9 nm respectively, after 12 weeks of implantation. The SPD sample exhibited much faster growth of newly formed HA compared to SPE. The growth of the newly formed HA was strongly dependent on the degree of HA crystallinity in the initial HA layer. After 12 weeks of implantation, the surface hardness value of the SPE and SPD samples decreased from 661  ±  0.4 HV to 586  ±  1.3 HV and from 585  ±  6.6 HV to 425  ±  86.9 HV respectively. The decrease in surface hardness values was due to the newly formed HA layer that was more porous than the initial HA layer. However, the values were still higher than the substrate surface hardness of 321  ±  28.8 HV. Wear test results suggest that the original HA layers for both samples were still strongly intact, and to a certain extent the newly grown HA layers also were strongly bound with the original HA layers. This study confirms the bioactivity and mechanical stability of the HA layer on both samples in vivo.
    Matched MeSH terms: Materials Testing
  2. Comparative efficacy of hemorrhage control of a novel mesoporous bioactive glass versus two commercial hemostats
    Pourshahrestani S, Kadri NA, Zeimaran E, Gargiulo N, Samuel S, Naveen SV, et al.
    Biomed Mater, 2018 02 08;13(2):025020.
    PMID: 29148431 DOI: 10.1088/1748-605X/aa9b3e
    Mesoporous bioactive glass containing 1% Ga2O3 (1%Ga-MBG) is attractive for hemorrhage control because of its surface chemistry which can promote blood-clotting. The present study compares this proprietary inorganic coagulation accelerator with two commercial hemostats, CeloxTM (CX) and QuikClot Advanced Clotting Sponge PlusTM (ACS+). The results indicate that the number of adherent platelets were higher on the 1%Ga-MBG and CX surfaces than ACS+ whereas a greater contact activation was seen on 1%Ga-MBG and ACS+ surfaces than CX. 1%Ga-MBG not only resulted in larger platelet aggregates and more extensive platelet pseudopodia compared to CX and ACS+ but also significantly accelerated the intrinsic pathways of the clotting cascade. In vitro thrombin generation assays also showed that CX and ACS+ induced low levels of thrombin formation while 1%Ga-MBG had significantly higher values. 1%Ga-MBG formed a larger red blood cell aggregate than both CX and ACS+. Direct exposure of 1%Ga-MBG to fibroblast cells increased cell viability after 3 days relative to CX and ACS+, inferring excellent cytocompatibility. The results of this study promote 1%Ga-MBG as a promising hemostat compared to the commercially available products as it possesses essential factors required for coagulation activation.
    Matched MeSH terms: Materials Testing
  3. Development of biodegradable thin films for efficient, specific and controlled delivery of capecitabine
    Gul I, Yunus U, Ajmal M, Bhatti MH, Chaudhry GE
    Biomed Mater, 2021 Aug 31;16(5).
    PMID: 34375958 DOI: 10.1088/1748-605X/ac1c61
    Cancer is the leading cause of death worldwide. Capecitabine (CP) shows severe side effects because of early metabolism in stomach that affects the normal cells and organs, particularly liver and stomach. In this scope, we report the biocompatible, nontoxic polymeric thin films loaded with anti-cancer drug, CP for target specific, sublingual delivery of CP. Chitosan (CS) and polyvinyl alcohol (PVA) were used as biodegradable polymers alongwith glutaraldehyde (GLA) cross linker. CP-loaded thin films (TFCP1-TFCP5) were fabricated by solvent casting method. The results of Fourier transform infrared spectroscopy confirmed the presence of CP and polymers (CS and PVA) with GLA which binds through hydrogen bonding, and compatibility of drug with different excipients. Thermogravemetric analysis showed that the thin films are highly stable while differential scanning calorimeter thermograms confirmed the complete miscibility/entrapment of CP within PVA/CS thin film matrix. X-ray diffraction patterns revealed the molecular ineractions between CP and polymer matrix. High degree of swelling index of thin films at pH 7.4 was observed in comparison to pH 5.5. CP release studies in acetate (pH 5.5) and phosphate buffer (pH 7.4) showed that the thin films swell and result in drug diffusion faster in phosphate buffer through diffusion governed by Higuchi's model. Cytotoxicity results displayed that CPTFs killed MCF-7 and T47D (human breast adenocarcinoma) cells more effectively as compared to CP alone. The results of adhesion assay also showed that the PVA and CS both are safe and biocompatible. TFCP1 and TFCP3 thin films efficiently induced the apoptosis as compared to CP alone. The improved ability of TFCP1 and TFCP3 to induce cytotoxicity in MCF-7 cells reflects the potential of these thin films for targeted drug delivery. The CPTFs were stable for 4 months at 4 °C/60% ± 2%RH and 25 °C/70% ± 2%RH. In conclusion, the thin film formulations showed target specific controlled and burst release properties and thus could prove to be effective for human breast cancer treatment.
    Matched MeSH terms: Materials Testing
  4. Compression and tension behavior of the prosthetic foam materials polyurethane, EVA, Pelite™ and a combination of polyurethane and EVA: a preliminary study
    Lutfi SNN, Abd Razak NA, Ali S, Gholizadeh H
    Biomed Tech (Berl), 2021 Jun 25;66(3):317-322.
    PMID: 34062632 DOI: 10.1515/bmt-2019-0110
    Materials with low-strength and low-impedance properties, such as elastomers and polymeric foams are major contributors to prosthetic liner design. Polyethylene-Light (Pelite™) is a foam liner that is the most frequently used in prosthetics but it does not cater to all amputees' limb and skin conditions. The study aims to investigate the newly modified Foam Liner, a combination of two different types of foams (EVA + PU + EVA) as the newly modified Foam Liner in terms of compressive and tensile properties in comparison to Pelite™, polyurethane (PU) foam, and ethylene-vinyl acetate (EVA) foam. Universal testing machine (AGS-X, Shimadzu, Kyoto, Japan) has been used to measure the tensile and compressive stress. Pelite™ had the highest compressive stress at 566.63 kPa and tensile stress at 1145 kPa. Foam Liner fell between EVA and Pelite™ with 551.83 kPa at compression and 715.40 kPa at tension. PU foam had the lowest compressive stress at 2.80 kPa and tensile stress at 33.93 kPa. Foam Liner has intermediate compressive elasticity but has high tensile elasticity compared to EVA and Pelite™. Pelite™ remains the highest in compressive and tensile stiffness. Although it is good for amputees with bony prominence, constant pressure might result in skin breakdown or ulcer. Foam Liner would be the best for amputees with soft tissues on the residual limbs to accommodate movement.
    Matched MeSH terms: Materials Testing*
  5. Microwave-assisted regeneration of activated carbon
    Foo KY, Hameed BH
    Bioresour Technol, 2012 Sep;119:234-40.
    PMID: 22728787 DOI: 10.1016/j.biortech.2012.05.061
    Microwave heating was used in the regeneration of methylene blue-loaded activated carbons produced from fibers (PFAC), empty fruit bunches (EFBAC) and shell (PSAC) of oil palm. The dye-loaded carbons were treated in a modified conventional microwave oven operated at 2450 MHz and irradiation time of 2, 3 and 5 min. The virgin properties of the origin and regenerated activated carbons were characterized by pore structural analysis and nitrogen adsorption isotherm. The surface chemistry was examined by zeta potential measurement and determination of surface acidity/basicity, while the adsorptive property was quantified using methylene blue (MB). Microwave irradiation preserved the pore structure, original active sites and adsorption capacity of the regenerated activated carbons. The carbon yield and the monolayer adsorption capacities for MB were maintained at 68.35-82.84% and 154.65-195.22 mg/g, even after five adsorption-regeneration cycles. The findings revealed the potential of microwave heating for regeneration of spent activated carbons.
    Matched MeSH terms: Materials Testing
  6. Wavelet neural networks applied to pulping of oil palm fronds
    Zainuddin Z, Wan Daud WR, Pauline O, Shafie A
    Bioresour Technol, 2011 Dec;102(23):10978-86.
    PMID: 21996481 DOI: 10.1016/j.biortech.2011.09.080
    In the organosolv pulping of the oil palm fronds, the influence of the operational variables of the pulping reactor (viz. cooking temperature and time, ethanol and NaOH concentration) on the properties of the resulting pulp (yield and kappa number) and paper sheets (tensile index and tear index) was investigated using a wavelet neural network model. The experimental results with error less than 0.0965 (in terms of MSE) were produced, and were then compared with those obtained from the response surface methodology. Performance assessment indicated that the neural network model possessed superior predictive ability than the polynomial model, since a very close agreement between the experimental and the predicted values was obtained.
    Matched MeSH terms: Materials Testing
  7. Enzymatic deinking of laser printed office waste papers: some governing parameters on deinking efficiency
    Lee CK, Darah I, Ibrahim CO
    Bioresour Technol, 2007 May;98(8):1684-9.
    PMID: 17137782
    The protocol for the enzymatic deinking of laser printed waste papers on a laboratory scale using cellulase (C) and hemicellulase (H) of Aspergillus niger (Amano) was developed as an effective method for paper recycling. A maximum deinking efficiency of almost 73% by the enzyme combination of C:H was obtained using the deinking conditions of pulping consistency of 1.0% (w/v) with the pulping time of 1.0min, temperature of 50 degrees C, pH=3.5, agitation rate of 60rpm, pulp concentration of 4% (w/v), concentration of each enzyme of 2.5U/g air dried pulp and the enzyme ratio of 1:1. The deinking efficiency was further enhanced to 95% using the optimized flotation system consisting of pH=6.0, Tween 80 of concentration 0.5% (w/w), working air flow rate of 10.0L/min and temperature of 45 degrees C. The deinked papers were found to exhibit properties comparable to the commercial papers suggesting the effectiveness of the enzymatic process developed.
    Matched MeSH terms: Materials Testing
  8. Some of the properties of flame retardant medium density fiberboard made from rubberwood and recycled containers containing aluminum trihydroxide
    Hashim R, How LS, Kumar RN, Sulaiman O
    Bioresour Technol, 2005 Nov;96(16):1826-31.
    PMID: 16051090
    The flame retardancy of medium density fiberboard (MDF) made from mixture of rubberwood fibers and recycled old corrugated containers was studied. Aluminum trihydroxide (ATH) was used as a fire retardant additive and mixed with the fibers to manufacture experimental MDF panels using wet process. Phenol formaldehyde (PF) resin in liquid, 2% based on oven dry weight of fibers, was used along with 0%, 10%, 15% and 20% of ATH. The flame retardant test was done using the limiting oxygen index (LOI) test. The other properties investigated include internal bond strength, thickness swelling and water absorption. The results showed that ATH loading increased as the LOI of MDF increased. This demonstrated that ATH could improved the fire retardant property of MDF at sufficient loading. An increase in concentration of ATH showed an increase in the IB values of MDF made without resin. MDF panels made without resin showed a progressive increase in internal bond as the composition of recycled old corrugated containers fiber increased. Addition of resin improved internal bond strength and reduced thickness swelling, and water absorption. Thickness swelling of panel increased as the composition of recycled old corrugated containers fiber increased. Scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX) showed that there is indication of ATH and resin filling the void space in between fibers.
    Matched MeSH terms: Materials Testing
  9. Synthesis and characterization of carbon cryogel microspheres from lignin-furfural mixtures for biodiesel production
    Zainol MM, Amin NA, Asmadi M
    Bioresour Technol, 2015 Aug;190:44-50.
    PMID: 25919936 DOI: 10.1016/j.biortech.2015.04.067
    The aim of this work was to study the potential of biofuel and biomass processing industry side-products as acid catalyst. The synthesis of carbon cryogel from lignin-furfural mixture, prepared via sol-gel polycondensation at 90°C for 0.5h, has been investigated for biodiesel production. The effect of lignin to furfural (L/F) ratios, lignin to water (L/W) ratios and acid concentration on carbon cryogel synthesis was studied. The carbon cryogels were characterized and tested for oleic acid conversion. The thermally stable amorphous spherical carbon cryogel has a large total surface area with high acidity. Experimental results revealed the optimum FAME yield and oleic acid conversion of 91.3wt.% and 98.1wt.%, respectively were attained at 65°C for 5h with 5wt.% catalyst loading and 20:1 methanol to oleic acid molar ratio. Therefore, carbon cryogel is highly potential for heterogeneous esterification of free fatty acid to biodiesel.
    Matched MeSH terms: Materials Testing
  10. Effect of pulping variables on the characteristics of oil-palm frond-fiber
    Wan Rosli WD, Law KN, Zainuddin Z, Asro R
    Bioresour Technol, 2004 Jul;93(3):233-40.
    PMID: 15062817
    Caustic pulping of oil-palm frond-fiber strands was conducted following a central composite design using a two-level factorial plan involving three pulping variables (temperature: 160-180 degrees C, time: 1-2 h, alkali charge: 20-30% NaOH). Responses of pulp properties to the process variables were analyzed using a statistical software (DESIGN-EXPERT). The results indicated that frond-fiber strands could be pulped with ease to about 35-45% yield. Statistically, the reaction time was not a significant factor while the influences of the treatment temperature and caustic charge were in general significantly relative to the properties of the resultant pulps.
    Matched MeSH terms: Materials Testing
  11. Polymethacrylate coated electrospun PHB fibers: An exquisite outlook for fabrication of paper-based biosensors
    Hosseini S, Azari P, Farahmand E, Gan SN, Rothan HA, Yusof R, et al.
    Biosens Bioelectron, 2015 Jul 15;69:257-64.
    PMID: 25765434 DOI: 10.1016/j.bios.2015.02.034
    Electrospun polyhydroxybutyrate (PHB) fibers were dip-coated by polymethyl methacrylate-co-methacrylic acid, poly(MMA-co-MAA), which was synthesized in different molar ratios of the monomers via free-radical polymerization. Fabricated platfrom was employed for immobilization of the dengue antibody and subsequent detection of dengue enveloped virus in enzyme-linked immunosorbent assay (ELISA). There is a major advantage for combination of electrospun fibers and copolymers. Fiber structre of electrospun PHB provides large specific surface area available for biomolecular interaction. In addition, polymer coated parts of the platform inherited the premanent presence of surface carboxyl (-COOH) groups from MAA segments of the copolymer which can be effectively used for covalent and physical protein immobilization. By tuning the concentration of MAA monomers in polymerization reaction the concentration of surface -COOH groups can be carefully controlled. Therefore two different techniques have been used for immobilization of the dengue antibody aimed for dengue detection: physical attachment of dengue antibodies to the surface and covalent immobilization of antibodies through carbodiimide chemistry. In that perspective, several different characterization techniques were employed to investigate the new polymeric fiber platform such as scanning electron microscopy (SEM), atomic force microscopy (AFM), water contact angle (WCA) measurement and UV-vis titration. Regardless of the immobilization techniques, substantially higher signal intensity was recorded from developed platform in comparison to the conventional ELISA assay.
    Matched MeSH terms: Materials Testing
  12. Minimizing tissue-material interaction in microsensor for subcutaneous glucose monitoring
    Ahmad F, Christenson A, Bainbridge M, Yusof AP, Ab Ghani S
    Biosens Bioelectron, 2007 Mar 15;22(8):1625-32.
    PMID: 16934449
    A new implantable electrocatalytic glucose sensor for subcutaneous glucose monitoring has been fabricated by immobilizing glucose oxidase on a chemically modified carbon fiber. The sensor was inserted subcutaneously on a male spraguely rat without any incision after dipping the microsensor in the rat's serum for 3 days. The so called "stained" microsensor, operated in the amperometric mode with an applied potential of +0.23 V versus Ag|AgCl, was able to directly measure the glucose concentration upon infusion of glucose. The results obtained were encouraging, with the response time was less than 2s and the apparent Michaelis-Menten value at 5.1+/-0.5mM. The "stained" microsensor shows good stability and reproducibility with constant response spanned over 25 days. Most common interferences in glucose analysis were minimized by the outerlayer Nafion. Hematology examinations showed minimal material-tissue interaction. Use of such mechanical devices will allow a more refined understanding towards glucose control in diabetic patients as the implanted microsensor was not effected by biocompatibility failures.
    Matched MeSH terms: Materials Testing
  13. Evaluation of in vitro corrosion behavior and biocompatibility of poly[xylitol-(1,12-dodecanedioate)](PXDD)-HA coated porous iron for bone scaffolds applications
    Md Yusop AH, Wan Ali WFF, Jamaludin FH, Szali Januddi F, Sarian MN, Saad N, et al.
    Biotechnol J, 2024 Mar;19(3):e2300464.
    PMID: 38509814 DOI: 10.1002/biot.202300464
    The present study evaluates the corrosion behavior of poly[xylitol-(1,12-dodecanedioate)](PXDD)-HA coated porous iron (PXDD140/HA-Fe) and its cell-material interaction aimed for temporary bone scaffold applications. The physicochemical analyses show that the addition of 20 wt.% HA into the PXDD polymers leads to a higher crystallinity and lower surface roughness. The corrosion assessments of the PXDD140/HA-Fe evaluated by electrochemical methods and surface chemistry analysis indicate that HA decelerates Fe corrosion due to a lower hydrolysis rate following lower PXDD content and being more crystalline. The cell viability and cell death mode evaluations of the PXDD140/HA-Fe exhibit favorable biocompatibility as compared to bare Fe and PXDD-Fe scaffolds owing to HA's bioactive properties. Thus, the PXDD140/HA-Fe scaffolds possess the potential to be used as a biodegradable bone implant.
    Matched MeSH terms: Materials Testing
  14. Fulltext CNS neurotoxicity of bacterial cellulose-poly(acrylamide-sodium acrylate) hydrogel: a future therapeutic carrier
    Pandey M, Mohd Amin MC
    CNS Neurosci Ther, 2014 Apr;20(4):377-8.
    PMID: 24588895 DOI: 10.1111/cns.12237
    Matched MeSH terms: Materials Testing
  15. Production and modification of nanofibrillated cellulose using various mechanical processes: a review
    Abdul Khalil HP, Davoudpour Y, Islam MN, Mustapha A, Sudesh K, Dungani R, et al.
    Carbohydr Polym, 2014 Jan;99:649-65.
    PMID: 24274556 DOI: 10.1016/j.carbpol.2013.08.069
    Nanofibrillated cellulose from biomass has recently gained attention owing to their biodegradable nature, low density, high mechanical properties, economic value and renewability. Although they still suffer from two major drawbacks. The first challenge is the exploration of raw materials and its application in nanocomposites production. Second one is high energy consumption regarding the mechanical fibrillation. However, pretreatments before mechanical isolation can overcome this problem. Hydrophilic nature of nano-size cellulose fibers restricts good dispersion of these materials in hydrophobic polymers and therefore, leads to lower mechanical properties. Surface modification before or after mechanical defibrillation could be a solution for this problem. Additionally, drying affects the size of nanofibers and its properties which needs to study further. This review focuses on recent developments in pretreatments, nanofibrillated cellulose production and its application in nanopaper applications, coating additives, security papers, food packaging, and surface modifications and also for first time its drying.
    Matched MeSH terms: Materials Testing
  16. Development of poly (1, 8-octanediol citrate)/chitosan blend films for tissue engineering applications
    Zeimaran E, Pourshahrestani S, Pingguan-Murphy B, Kong D, Naveen SV, Kamarul T, et al.
    Carbohydr Polym, 2017 Nov 01;175:618-627.
    PMID: 28917909 DOI: 10.1016/j.carbpol.2017.08.038
    Blends of poly (1, 8-octanediol citrate) (POC) and chitosan (CS) were prepared through solution casting technique. Films with different component fractions (POC/CS: 100/0, 90/10, 80/20, 70/30, 60/40, and 0/100) were successfully prepared and characterized for their mechanical, thermal, structural and morphological properties as well as biocompatibility. The incorporation of CS to POC significantly increased tensile strength and elastic modulus and presented limited influences on pH variation which is important to the biocompatibility of biomaterial implants. The assessment of surface topography indicated that blending could enhance and control the surface roughness of the pure films. POC/CS blends well-supported human dermal fibroblast cells attachment and proliferation, and thus can be used for a range of tissue engineering applications.
    Matched MeSH terms: Materials Testing
  17. Fabrication and Testing of Electrospun Polyurethane Blended with Chitosan Nanoparticles for Vascular Graft Applications
    Subramaniam R, Mani MP, Jaganathan SK
    Cardiovasc Eng Technol, 2018 09;9(3):503-513.
    PMID: 29700782 DOI: 10.1007/s13239-018-0357-y
    In this study, a small vascular graft based on polyurethane (PU) blended with chitosan (Ch) nanoparticles was fabricated using electrospinning technique. Initially, the chitosan nanoparticles were synthesized using ionic gelation method. UV-Vis spectrophotometer confirmed the presence of synthesized Ch nanoparticles by exhibiting absorption peak at 288 nm and the Fourier-transform infrared spectroscopy (FTIR) analysis confirmed the existence of the chitosan. Further, the synthesized Ch nanoparticles showed size diameter in the range of 134 ± 58 nm as measured using ImageJ. In the electrospun PU/chitosan graft, the fiber diameter and pore size diameter was found to be reduced compared to the pure PU owing to incorporation of chitosan into PU matrix. The FTIR spectrum revealed the presence of chitosan in the prepared nanocomposite membrane by the formation of the hydrogen bond and peak shift of CH and NH stretching. Moreover, the contact angle measurements revealed that the prepared graft showed decreased contact angle indicating hydrophilic nature compared to the pristine PU. The cytocompatibility studies revealed the non-toxic behavior of the fabricated graft. Hence, the prepared graft exhibiting significant physiochemical and non-toxic properties may be a plausible candidate for cardiovascular graft applications.
    Matched MeSH terms: Materials Testing
  18. Synergy of silica sand and waste plastics as thermoplastic composites on abrasive wear characteristics under conditions of different loads and sliding speeds
    Soni A, Das PK, Yusuf M, Ridha S, Kamyab H, Alam MA, et al.
    Chemosphere, 2023 May;323:138233.
    PMID: 36863626 DOI: 10.1016/j.chemosphere.2023.138233
    The diverse nature of polymers with attractive properties has replaced the conventional materials with polymeric composites. The present study was sought to evaluate the wear performance of thermoplastic-based composites under the conditions of different loads and sliding speeds. In the present study, nine different composites were developed by using low-density polyethylene (LDPE), high-density polyethylene (HDPE) and polyethylene terephthalate (PET) with partial sand replacements i.e., 0, 30, 40, and 50 wt%. The abrasive wear was evaluated as per the ASTM G65 standard test for abrasive wear through a dry-sand rubber wheel apparatus under the applied loads of 34.335, 56.898, 68.719, 79.461 and 90.742 (N) and sliding speeds of 0.5388, 0.7184, 0.8980, 1.0776 and 1.4369 (m/s). The optimum density and compressive strength were obtained to be 2.0555 g/cm3 and 46.20 N/mm2, respectively for the composites HDPE60 and HDPE50 respectively. The minimum value of abrasive wear were found to 0.02498, 0.03430, 0.03095, 0.09020 and 0.03267 (cm3) under the considered loads of 34.335, 56.898, 68.719, 79.461 and 90.742 (N), respectively. Moreover, the composites LDPE50, LDPE100, LDPE100, LDPE50PET20 and LDPE60 showed a minimum abrasive wear of 0.03267, 0.05949, 0.05949, 0.03095 and 0.10292 at the sliding speeds of 0.5388, 0.7184, 0.8980, 1.0776 and 1.4369 (m/s), respectively. The wear response varied non-linearly with the conditions of loads and sliding speeds. Micro-cutting, plastic deformations, fiber peelings, etc. were included as the possible wear mechanism. The possible correlations between wear and mechanical properties, and throughout discussions for wear behaviors through the morphological analyses of the worn-out surfaces were provided.
    Matched MeSH terms: Materials Testing
  19. In vitro comparative study of white and dark polycaprolactone trifumarate in situ cross-linkable scaffolds seeded with rat bone marrow stromal cells
    Muhammad KB, Abas WA, Kim KH, Pingguan-Murphy B, Zain NM, Akram H
    Clinics (Sao Paulo), 2012;67(6):629-38.
    PMID: 22760903
    OBJECTIVE: Dark poly(caprolactone) trifumarate is a successful candidate for use as a bone tissue engineering scaffold. Recently, a white polymeric scaffold was developed that shows a shorter synthesis time and is more convenient for tissue-staining work. This is an in vitro comparative study of both the white and dark scaffolds.

    METHODS: Both white and dark poly(caprolactone) trifumarate macromers were characterized via Fourier transform infrared spectroscopy before being chemically cross-linked and molded into disc-shaped scaffolds. Biodegradability was assessed by percentage weight loss on days 7, 14, 28, 42 and 56 (n = 5) after immersion in 10% serum-supplemented medium or distilled water. Static cell seeding was employed in which isolated and characterized rat bone marrow stromal cells were seeded directly onto the scaffold surface. Seeded scaffolds were subjected to a series of biochemical assays and scanning electron microscopy at specified time intervals for up to 28 days of incubation.

    RESULTS: The degradation of the white scaffold was significantly lower compared with the dark scaffold but was within the acceptable time range for bone-healing processes. The deoxyribonucleic acid and collagen contents increased up to day 28 with no significant difference between the two scaffolds, but the glycosaminoglycan content was slightly higher in the white scaffold throughout 14 days of incubation. Scanning electron microscopy at day 1 [corrected] revealed cellular growth and attachment.

    CONCLUSIONS: There was no cell growth advantage between the two forms, but the white scaffold had a slower biodegradability rate, suggesting that the newly synthesized poly(caprolactone) trifumarate is more suitable for use as a bone tissue engineering scaffold.

    Matched MeSH terms: Materials Testing
  20. Polyelectrolyte multi-layers assembly of SiCHA nanopowders and collagen type I on aminolysed PLA films to enhance cell-material interactions
    Baba Ismail YM, Ferreira AM, Bretcanu O, Dalgarno K, El Haj AJ
    Colloids Surf B Biointerfaces, 2017 Nov 01;159:445-453.
    PMID: 28837894 DOI: 10.1016/j.colsurfb.2017.07.086
    This paper presents a new approach in assembling bone extracellular matrix components onto PLA films, and investigates the most favourable environment which can be created using the technique for cell-material interactions. Poly (lactic acid) (PLA) films were chemically modified by covalently binding the poly(ethylene imine) (PEI) as to prepare the substrate for immobilization of polyelectrolyte multilayers (PEMs) coating. Negatively charged polyelectrolyte consists of well-dispersed silicon-carbonated hydroxyapatite (SiCHA) nanopowders in hyaluronic acid (Hya) was deposited onto the modified PLA films followed by SiCHA in collagen type I as the positively charged polyelectrolyte. The outermost layer was finally cross-linked by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrocholoride and N-hydroxysulfosuccinimide sodium salt (EDC/NHS) solutions. The physicochemical features of the coated PLA films were monitored via X-ray Photoelectron Spectroscopy (XPS) and Atomic Force Microscope (AFM). The amounts of calcium and collagen deposited on the surface were qualitatively and quantitatively determined. The surface characterizations suggested that 5-BL has the optimum surface roughness and highest amounts of calcium and collagen depositions among tested films. In vitro human mesenchymal stem cells (hMSCs) cultured on the coated PLA films confirmed that the coating materials greatly improved cell attachment and survival compared to unmodified PLA films. The cell viability, cell proliferation and Alkaline Phosphatase (ALP) expression on 5-BL were found to be the most favourable of the tested films. Hence, this newly developed coating materials assembly could contribute to the improvement of the bioactivity of polymeric materials and structures aimed to bone tissue engineering applications.
    Matched MeSH terms: Materials Testing/methods*
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