Chemically functionalized carbon nanotubes are highly suitable and promising materials for potential biomedical applications like drug delivery due to their distinct physico-chemical characteristics and unique architecture. However, they are often associated with problems like insoluble in physiological environment and cytotoxicity issue due to impurities and catalyst residues contained in the nanotubes. On the other hand, surface coating agents play an essential role in preventing the nanoparticles from excessive agglomeration as well as providing good water dispersibility by replacing the hydrophobic surfaces of nanoparticles with hydrophilic moieties. Therefore, we have prepared four types of biopolymer-coated single walled carbon nanotubes systems functionalized with anticancer drug, betulinic acid in the presence of Tween 20, Tween 80, polyethylene glycol and chitosan as a comparative study. The Fourier transform infrared spectroscopy studies confirm the bonding of the coating molecules with the SWBA and these results were further supported by Raman spectroscopy. All chemically coated samples were found to release the drug in a slow, sustained and prolonged fashion compared to the uncoated ones, with the best fit to pseudo-second order kinetic model. The cytotoxic effects of the synthesized samples were evaluated in mouse embryonic fibroblast cells (3T3) at 24, 48 and 72 h. The in vitro results reveal that the cytotoxicity of the samples were dependent upon the drug release profiles as well as the chemical components of the surface coating agents. In general, the initial burst, drug release pattern and cytotoxicity could be well-controlled by carefully selecting the desired materials to suit different therapeutic applications.
Bioactive glasses may function as antimicrobial delivery systems through the incorporation and subsequent release of therapeutic ions. The aim of this study was to evaluate the antimicrobial properties of a series of composite scaffolds composed of poly(octanediol citrate) with increased loads of a bioactive glass that releases zinc (Zn(2+)) and gallium (Ga(3+)) ions in a controlled manner. The antibacterial activity of these scaffolds was investigated against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The ability of the scaffolds to release ions and the subsequent ingress of these ions into hard tissue was evaluated using a bovine bone model. Scaffolds containing bioactive glass exhibited antibacterial activity and this increased in vitro with higher bioactive glass loads; viable cells decreased to about 20 % for the composite scaffold containing 30 % bioactive glass. The Ga(3+) release rate increased as a function of time and Zn(2+) was shown to incorporate into the surrounding bone.
The present study investigates the development of methyl cellulose (MC)-sodium alginate (SA)-montmorillonite (MMT) clay based bionanocomposite films with interesting wound healing properties. The differential scanning calorimetry analysis of the composite films revealed presence of single glass transition temperature (Tg) confirming the miscible nature of the ternary blended films. The increase in MMT ratio in the composite films reduced the mobility of biopolymer chains (MC/SA) which increased the Tg of the film. Thermogravimetric analysis showed that dispersion of clay (MMT) at nano level significantly delayed the weight loss that correlated with higher thermal stability of the composite films. It was observed that the developed films were able to exhibit antimicrobial activity against four typical pathogenic bacteria found in the presence of wound. The developed films were able to significantly inhibit (10 mg/ml) the growth of Enterococcus faecium and Pseudomonas aeruginosa. In vitro scratch assay indicated potential wound closure activities of MC-2-4 bionanocomposite films at their respective highest subtoxic doses. In conclusion, these ternary bionanocomposite films were found to be promising systems for wound healing applications.
Stimuli responsive hydrogels have shown enormous potential as a carrier for targeted drug delivery. In this study we have developed novel pH responsive hydrogels for the delivery of 5-fluorouracil (5-FU) in order to alleviate its antitumor activity while reducing its toxicity. We used 2-(methacryloyloxyethyl) trimetylammonium chloride a positively charged monomer and methacrylic acid for fabricating the pH responsive hydrogels. The released 5-FU from all except hydrogel (GEL-5) remained biologically active against human colon cancer cell lines [HT29 (IC50 = 110-190 μg ml(-1)) and HCT116 (IC50 = 210-390 μg ml(-1))] but not human skin fibroblast cells [BJ (CRL2522); IC50 ≥ 1000 μg ml(-1)]. This implies that the copolymer hydrogels (1-4) were able to release 5-FU effectively to colon cancer cells but not normal human skin fibroblast cells. This is probably due to the shorter doubling time that results in reduced pH in colon cancer cells when compared to fibroblast cells. These pH sensitive hydrogels showed well defined cell apoptosis in HCT116 cells through series of events such as chromatin condensation, membrane blebbing, and formation of apoptotic bodies. No cell killing was observed in the case of blank hydrogels. The results showed the potential of these stimuli responsive polymer hydrogels as a carrier for colon cancer delivery.
This study aims to pre-assess the in vitro and in vivo biocompatibility of poly(vinyl alcohol)-carboxylmethyl-chitosan-poly(ethylene glycol) (PCP) scaffold. PCP was lyophilised to create supermacroporous structures. 3-(4, 5-dimethyl-thiazol-2yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and immunohistochemistry (IHC) were used to evaluate the effectiveness of PCP scaffolds for chondrocytes attachment and proliferation. The ultrastructural was assessed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Extracellular matrix (ECM) formation was evaluated using collagen type-II staining, glycosaminoglycan (GAG) and collagen assays. Histological analysis was conducted on 3-week implanted Sprague-Dawley rats. The MTT, IHC, SEM and TEM analyses confirm that PCP scaffolds promoted cell attachment and proliferation in vitro. The chondrocyte-PCP constructs secreted GAG and collagen type-II, both increased significantly from day-14 to day-28 (P
In this study, MgO nanoparticles are applied to control the initial burst release by modification of matrix structure, thereby affecting the release mechanism. The effects of MgO nanofiller loading on the in vitro release of a model drug are investigated. Surface topography and release kinetics of hydrogel nanocomposites are also studied in order to have better insight into the release mechanism. It was found that the incorporation of MgO nanofillers can significantly decrease the initial burst release. The effect of genipin (GN) on burst release was also compared with MgO nanoparticles, and it was found that the impact of MgO on burst release reduction is more obvious than GN; however, GN cross-linking caused greater final release compared to blanks and nanocomposites. To confirm the capability of nanocomposite hydrogels to reduce burst release, the release of β-carotene in Simulated Gastric Fluid and Simulated Intestinal Fluid was also carried out. Thus, the application of MgO nanoparticles seems to be a promising strategy to control burst release.
The use of mesenchymal stem cells (MSCs) in tissue repair and regeneration despite their multipotentiality has been limited by their cell source quantity and decelerating proliferative yield efficiency. A study was thus undertaken to determine the feasibility of using microcarrier beads in spinner flask cultures for MSCs expansion and compared to that of conventional monolayer cultures and static microcarrier cultures. Isolation and characterization of bone marrow derived MSCs were conducted from six adult New Zealand white rabbits. Analysis of cell morphology on microcarriers and culture plates at different time points (D0, D3, D10, D14) during cell culture were performed using scanning electron microscopy and bright field microscopy. Cell proliferation rates and cell number were measured over a period of 14 days, respectively followed by post-expansion characterization. MTT proliferation assay demonstrated a 3.20 fold increase in cell proliferation rates in MSCs cultured on microcarriers in spinner flask as compared to monolayer cultures (p < 0.05). Cell counts at day 14 were higher in those seeded on stirred microcarrier cultures (6.24 ± 0.0420 cells/ml) × 10(5) as compared to monolayer cultures (0.22 ± 0.004 cells/ml) × 10(5) and static microcarrier cultures (0.20 ± 0.002 cells/ml) × 10(5). Scanning electron microscopy demonstrated an increase in cell colonization of the cells on the microcarriers in stirred cultures. Bead-expanded MSCs were successfully differentiated into osteogenic and chondrogenic lineages. This system offers an improved and efficient alternative for culturing MSCs with preservation to their phenotype and multipotentiality.
The aim of this study was to engineer skeletal muscle tissue for repair abdominal wall defects. Myoblast were seeded onto the scaffolds and cultivated in vitro for 5 days. Full thickness abdominal wall defects (3 x 4 cm) were created in 18 male New Zealand white rabbits and randomly divided into two equal groups. The defects of the first group were repaired with myoblast-seeded-bovine tunica vaginalis whereas the second group repaired with non-seeded-bovine tunica vaginalis and function as a control. Three animals were sacrificed at 7th, 14th, and 30th days of post-implantation from each group and the explanted specimens were subjected to macroscopic and microscopic analysis. In every case, seeded scaffolds have better deposition of newly formed collagen with neo-vascularisation than control group. Interestingly, multinucleated myotubes and myofibers were only detected in cell-seeded group. This study demonstrated that myoblast-seeded-bovine tunica vaginalis can be used as an effective scaffold to repair severe and large abdominal wall defects with regeneration of skeletal muscle tissue.
5-Fluororaucil (5-FU) as anti-cancer drug was reported to induce thymidine synthase (TS) overexpression and cancer cell resistance. To improve its therapeutic efficacy and selective targeting, here we developed a targeted delivery system mediated by the active ligand-folate receptor chemistry to deliver the 5-FU drug selectively into the tumor microenvironment. The preparation was achieved by exploring chitosan (CS)-biopolymer based system with folic acid (FA)-conjugation. The 5-FU@FACS-Mn:ZnS quantum dots (QDs) based on the histological assessment conducted in the 4T1 challenged mice showed an improved tumor remission in the liver, spleen and lungs. The 5-FU@FACS-Mn:ZnS composite induced anti-proliferative properties in these organs as compared to the free 5-FU drug. Unlike the 5-FU@FACS-Mn:ZnS treated groups which showed some specific morphological changes such as cell shrinkage without obvious presence of adipocytes, the excised section of the tumor in the untreated control group and the free 5-FU drug treated group showed necrotic and degenerated cells; these cells are multifocally distributed in the tumor mass with evidence of widely distributed adipocytes within the tumor mass. These findings suggest that the 5-FU@FACS-Mn:ZnS composite has a superior role during the induction of apoptosis in the 4T1 cells as compared to the free 5-FU drug treated groups. The results of the study therefore suggest that the impregnation of 5-FU anti-cancer drug within the FACS-Mn:ZnS system significantly improves its selective targeting efficacy, in addition to improving the anti-proliferative properties and attenuate possible tumor resistances to the 5-FU drug. The work discusses about the anti-metastatic effects of folic acid-bound 5-Fluororacil loaded Mn:ZnS quantum dots towards 4T1 cell line proliferation in mice based on the histological analysis.
The objective of this study was to prepare periodontal gels using natural polymers such as badam gum, karaya gum and chitosan. These gels were tested for their physical and biochemical properties and assessed for their antibacterial activity against Aggregatibacter actinomycetemcomitans and Streptococcus mutans, two pathogens associated with periodontal disease. Badam gum, karaya gum and chitosan were used to prepare gels of varying concentrations. Moxifloxacin hydrochloride, a known antimicrobial drug was choosen in the present study and it was added to the above gels. The gels were then run through a battery of tests in order to determine their physical properties such as pH and viscosity. Diffusion studies were carried out on the gels containing the drug. Antimicrobial testing of the gels against various bacteria was then carried out to determine the effectiveness of the gels against these pathogens. The results showed that natural polymers can be used to produce gels. These gels do not have inherent antimicrobial properties against A. actinomycetemcomitans and S. mutans. However, they can be used as a transport vehicle to carry and release antimicrobial drugs.
This study aimed to explore a potential use of fish scale-derived gelatin nanofibrous scaffolds (GNS) in tissue engineering due to their biological and economical merits. Extraction of gelatin was achieved via decalcification, sonication and lyophilization of mixed fish scales. To fabricate nano-scale architecture of scaffolds analogous to natural extracellular matrix, gelatin was rendered into nanofibrous matrices through 6-h electrospinning, resulting in the average diameter of 48 ± 12 nm. In order to improve the water-resistant ability while retaining their biocompatibility, GNS were physically crosslinked with ultraviolet (UV) irradiation for 5 min (UGN5), 10 min (UGN10) and 20 min (UGN20). On average, the diameter of nanofibers increased by 3 folds after crosslinking, however, Fourier transform infrared spectroscopy analysis confirmed that no major alterations occurred in the functional groups of gelatin. A degradation assay showed that UGN5 and UGN10 scaffolds remained in minimum essential medium for 14 days, while UGN20 scaffolds degraded completely after 10 days. All UGN scaffolds promoted adhesion and proliferation of human keratinocytes, HaCaT, without causing an apparent cytotoxicity. UGN5 scaffolds were shown to stimulate a better growth of HaCaT cells compared to other scaffolds upon 1 day of incubation, whereas UGN20 had a long-term effect on cells exhibiting 25% higher cell proliferation than positive control after 7 days. In the wound scratch assay, UGN5 scaffolds induced a rapid cell migration closing up to 79% of an artificial wound within 24 h. The current findings provide a new insight of UGN scaffolds to serve as wound dressings in the future. In the wound scratch assay, UGN5 induced a rapid cell migration closing up to 79% of an artificial wound within 24 h.
Hydroxyapatite is an ideal biomaterial for bone tissue engineering due to its biocompatibility and hemocompatibility which have been widely studied by many researchers. The incorporation of nanoporosity into hydroxyapatite could transform the biomaterial into an effective adsorbent for uremic toxins removal especially in artificial kidney system. However, the effect of nanoporosity incorporation on the hemocompatibility of hydroxyapatite has yet to be answered. In this study, nanoporous hydroxyapatite was synthesized using hydrothermal technique and its hemocompatibility was determined. Non-ionic surfactants were used as soft templates to create porosity in the hydroxyapatite. The presence of pure hydroxyapatite phase in the synthesized samples is validated by X-ray diffraction analysis and Fourier transform infrared spectroscopy. The TEM images show that the hydroxyapatite formed rod-like particles with the length of 21-90 nm and diameter of 11-70 nm. The hydroxyapatite samples exhibit BET surface area of 33-45 m2 g-1 and pore volume of 0.35-0.44 cm3 g-1. The hemocompatibility of the hydroxyapatite was determined via hemolysis test, platelet adhesion, platelet activation and blood clotting time measurement. The nanoporous hydroxyapatite shows less than 5% hemolysis, suggesting that the sample is highly hemocompatible. There is no activation and morphological change observed on the platelets adhered onto the hydroxyapatite. The blood clotting time demonstrates that the blood incubated with the hydroxyapatite did not coagulate. This study summarizes that the synthesized nanoporous hydroxyapatite is a highly hemocompatible biomaterial and could potentially be utilized in biomedical applications.
The success of wound healing depends upon the proper growth of vascular system in time in the damaged tissues. Poor blood supply to wounded tissues or tissue engineered grafts leads to the failure of wound healing or rejection of grafts. In present paper, we report the synthesis of novel organosoluble and pro-angiogenic chitosan derivative (CSD) by the reaction of chitosan with 1,3-dimethylbarbituric acid and triethylorthoformate (TEOF). The synthesized material was characterized by FTIR and 13C-NMR to confirm the incorporated functional groups and new covalent connectivities. Biodegradability of the synthesized chitosan derivative was tested in the presence of lysozyme and was found to be comparable with CS. The cytotoxicity and apoptosis effect of new derivative was determined against gastric adenocarcinoma (AGS) cells and was found to be non-toxic. The CSD was found to be soluble in majority of organic solvents. It was blended with polycaprolactone (PCL) to form composite scaffolds. From an ex ovo CAM assay, it was noted that CSD stimulated the angiogenesis.
The current study is proposing a design envelope for porous Ti-6Al-4V alloy femoral stems to survive under fatigue loads. Numerical computational analysis of these stems with a body-centered-cube (BCC) structure is conducted in ABAQUS. Femoral stems without shell and with various outer dense shell thicknesses (0.5, 1.0, 1.5, and 2 mm) and inner cores (porosities of 90, 77, 63, 47, 30, and 18%) are analyzed. A design space (envelope) is derived by using stem stiffnesses close to that of the femur bone, maximum fatigue stresses of 0.3σys in the porous part, and endurance limits of the dense part of the stems. The Soderberg approach is successfully employed to compute the factor of safety Nf > 1.1. Fully porous stems without dense shells are concluded to fail under fatigue load. It is thus safe to use the porous stems with a shell thickness of 1.5 and 2 mm for all porosities (18-90%), 1 mm shell with 18 and 30% porosities, and 0.5 mm shell with 18% porosity. The reduction in stress shielding was achieved by 28%. Porous stems incorporated BCC structures with dense shells and beads were successfully printed.
Recently, surface engineered biomaterials through surface modification are extensively investigated due to its potential to enhance cellular homing and migration which contributes to a successful drug delivery process. This study is focused on osteoblasts response towards surface engineered using a simple sodium hydroxide (NaOH) hydrolysis and growth factors conjugated poly(lactic acid) (PLA) microspheres. In this study, evaluation of the relationship of NaOH concentration with the molecular weight changes and surface morphology of PLA microspheres specifically wall thickness and porosity prior to in vitro studies was investigated. NaOH hydrolysis of 0.1 M, 0.3 M and 0.5 M were done to introduce hydrophilicity on the PLA prior to conjugation with basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF). Morphology changes showed that higher concentration of NaOH could accelerate the hydrolysis process as the highest wall thickness was observed at 0.5 M NaOH with ~3.52 µm. All surface modified and growth factors conjugated PLA microspheres wells enhanced the migration of the cells during wound healing process as wound closure was 100% after 3 days of treatment. Increase in hydrophilicity of the surface engineered and growth factors conjugated PLA microspheres provides favorable surface for cellular attachment of osteoblast, which was reflected by positive DAPI staining of the cells' nucleus. Surface modified and growth factors conjugated PLA microspheres were also able to enhance the capability of the PLA in facilitating the differentiation process of mesenchymal stem cells (MSCs) into osteogenic lineage since only positive stain was observed on surface engineered and growth factors conjugated PLA microspheres. These results indicated that the surface engineered and growth factors conjugated PLA microspheres were non-toxic for biological environments and the improved hydrophilicity made them a potential candidate as a drug delivery vehicle as the cells can adhere, attach and proliferate inside it.