Waste materials from natural sources are important resources for extraction and recovery of valuable compounds. Transformation of these waste materials into valuable materials requires specific techniques and approaches. Hydroxyapatite (HAp) is a biomaterial that can be extracted from natural wastes. HAp has been widely used in biomedical applications owing to its excellent bioactivity, high biocompatibility, and excellent osteoconduction characteristics. Thus, HAp is gaining prominence for applications as orthopaedic implants and dental materials. This review summarizes some of the recent methods for extraction of HAp from natural sources including mammalian, aquatic or marine sources, shell sources, plants and algae, and from mineral sources. The extraction methods used to obtain hydroxyapatite are also described. The effect of extraction process and natural waste source on the critical properties of the HAp such as Ca/P ratio, crystallinity and phase assemblage, particle sizes, and morphology are discussed herein.
A novel injectable calcium phosphate bone cement (osteopaste) has been
developed. Its potential application in orthopaedics as a filler of bone defects has been
studied. The biomaterial was composed of tetra-calcium phosphate (TTCP) and tricalcium
phosphate (TCP) powder. The aim of the present study was to evaluate the
healing process of osteopaste in rabbit tibia.(Copied from article).
Polylactic acid (PLA) nanocomposites reinforced with hybrid montmorillonite/cellulose nanowhiskers [MMT/CNW(SO4)] were prepared by solution casting. The CNW(SO4) nanofiller was first isolated from microcrystalline cellulose using acid hydrolysis treatment. PLA/MMT/CNW(SO4) hybrid nanocomposites were prepared by the addition of various amounts of CNW(SO4) [1-9 parts per hundred parts of polymer (phr)] into PLA/MMT nanocomposite at 5 phr MMT content, based on highest tensile strength values as reported previously. The biodegradability, thermal, tensile, morphological, water absorption and transparency properties of PLA/MMT/CNW(SO4) hybrid nanocomposites were investigated. The Biodegradability, thermal stability and crystallinity of hybrid nanocomposites increased compared to PLA/MMT nanocomposite and neat PLA. The highest tensile strength of hybrid nanocomposites was obtained by incorporating 1 phr CNW(SO4) [∼ 36 MPa]. Interestingly, the ductility of hybrid nanocomposites increased significantly by 87% at this formulation. The Young's modulus increased linearly with increasing CNW(SO4) content. This is due to the relatively good dispersion of nanofillers in the hybrid nanocomposites, as revealed by transmission electron microscopy. Fourier transform infrared spectroscopy indicated the formation of some polar interactions. In addition, water resistance of the hybrid nanocomposites improved and the visual transparency of neat PLA film did not affect by addition of CNW(SO4).
In this study, a chitosan co-polymer scaffold was prepared by mixing poly(vinyl alcohol) (PVA), NO, carboxymethyl chitosan (NOCC) and polyethylene glycol (PEG) solutions to obtain desirable properties for chondrocyte cultivation. Electron beam (e-beam) radiation was used to physically cross-link these polymers at different doses (30 kGy and 50 kGy). The co-polymers were then lyophilized to form macroporous three-dimensional (3-D) matrix. Scaffold morphology, porosity, swelling properties, biocompatibility, expression of glycosaminoglycan (GAG) and type II collagen following the seeding of primary chondrocytes were studied up to 28 days. The results demonstrate that irradiation of e-beam at 50 kGy increased scaffold porosity and pore sizes subsequently enhanced cell attachment and proliferation. Scanning electron microscopy and transmission electron microscopy revealed extensive interconnected microstructure of PVA-PEG-NOCC, demonstrated cellular activities on the scaffolds and their ability to maintain chondrocyte phenotype. In addition, the produced PVA-PEG-NOCC scaffolds showed superior swelling properties, and increased GAG and type II collagen secreted by the seeded chondrocytes. In conclusion, the results suggest that by adding NOCC and irradiation cross-linking at 50 kGy, the physical and biological properties of PVA-PEG blend can be further enhanced thereby making PVA-PEG-NOCC a potential scaffold for chondrocytes.
The effects of organic solvents and their binary mixture in the glucose functionalization of bacterial poly-3-hydroxyalkanoates catalyzed by Lecitase™ Ultra were studied. Equal volume binary mixture of DMSO and chloroform with moderate polarity was more effective for the enzyme catalyzed synthesis of the carbohydrate polymer at ≈38.2 (±0.8)% reactant conversion as compared to the mono-phasic and other binary solvents studied. The apparent reaction rate constant as a function of medium water activity (aw) was observed to increase with increasing solvent polarity, with optimum aw of 0.2, 0.4 and 0.7 (±0.1) observed in hydrophilic DMSO, binary mixture DMSO:isooctane and hydrophobic isooctane, respectively. Molecular sieve loading between 13 to 15gL(-1) (±0.2) and reaction temperature between 40 to 50°C were found optimal. Functionalized PHA polymer showed potential characteristics and biodegradability.
This study is focusing to develop a porous biocompatible scaffold using hydroxyethyl cellulose (HEC) and poly (vinyl alcohol) (PVA) with improved cellular adhesion profiles and stability. The combination of HEC and PVA were synthesized using freeze-drying technique and characterized using SEM, ATR-FTIR, TGA, DSC, and UTM. Pore size of HEC/PVA (2-40 μm) scaffolds showed diameter in a range of both pure HEC (2-20 μm) and PVA (14-70 μm). All scaffolds revealed high porosity above 85%. The water uptake of HEC was controlled by PVA cooperation in the polymer matrix. After 7 days, all blended scaffolds showed low degradation rate with the increased of PVA composition. The FTIR and TGA results explicit possible chemical interactions and mass loss of blended scaffolds, respectively. The Tg values of DSC curved in range of HEC and PVA represented the miscibility of HEC/PVA blend polymers. Higher Young's modulus was obtained with the increasing of HEC value. Cell-scaffolds interaction demonstrated that human fibroblast (hFB) cells adhered to polymer matrices with better cell proliferation observed after 7 days of cultivation. These results suggested that biocompatible of HEC/PVA scaffolds fabricated by freeze-drying method might be suitable for skin tissue engineering applications.
Edible duck feet gelatin (DFG)-based biocomposites with different glycerol (GLY) contents (15%, 25%, and 35% of dried DFG) were prepared. Physicochemical, mechanical, barrier, and heat seal properties of DFG films were characterized and compared as an alternative to bovine gelatin film. Increasing glycerol from 15 to 35% decreased the TS and YM and EB and HS increased, in value of 42.54-7.27 and 1240-157.10MPa and 22.82-50.33% and 42.06-347.15N/m respectively. The water vapor permeability (WVP) and oxygen permeability (OP) of films were increased from 4.78 to 5.6×10-11gm-1Pa-1s-1 and from 3.97 to 33.99cm3mμ/m2 d kPa respectively. GAB model estimations showed monolayer water content of films increased with the increase of plasticizer content. Moisture sorption isotherm modelling exhibited a type II BET classification. Fourier transform infrared (FTIR) spectra showed shifted peak at approximately 1024cm-1, which was related to glycerol. The results show that the properties of DFG film are suitable for use as an alternative material to bovine gelatin film.
The zinc oxide nanoparticles (particles size <50nm) incorporated into chitosan-collagen 3D porous scaffolds and investigated the effect of zinc oxide nanoparticles incorporation on microstructure, mechanical properties, biodegradation and cytocompatibility of 3D porous scaffolds. The 0.5%, 1.0%, 2.0% and 4.0% zinc oxide nanoparticles chitosan-collagen 3D porous scaffolds were fabricated via freeze-drying technique. The zinc oxide nanoparticles incorporation effects consisting in chitosan-collagen 3D porous scaffolds were investigated by mechanical and swelling tests, and effect on the morphology of scaffolds examined microscopically. The biodegradation and cytocompatibility tests were used to investigate the effects of zinc oxide nanoparticles incorporation on the ability of scaffolds to use for tissue engineering application. The mean pore size and swelling ratio of scaffolds were decreased upon incorporation of zinc oxide nanoparticles however, the porosity, tensile modulus and biodegradation rate were increased upon incorporation of zinc oxide nanoparticles. In vitro culture of human fibroblasts and keratinocytes showed that the zinc oxide nanoparticles facilitated cell adhesion, proliferation and infiltration of chitosan-collagen 3D porous scaffolds. It was found that the zinc oxide nanoparticles incorporation enhanced porosity, tensile modulus and cytocompatibility of chitosan-collagen 3D porous scaffolds.
In this study, biodegradable composite films were prepared by using thermoplastic cornstarch matrix and corn husk fiber as a reinforcing filler. The composite films were manufactured via a casting technique using different concentrations of husk fiber (0-8%), and fructose as a plasticizer at a fixed amount of 25% for starch weight. The Physical, thermal, morphological, and tensile characteristics of composite films were investigated. The findings indicated that the incorporation of husk fiber, in general, enhanced the performance of the composite films. There was a noticeable reduction in the density and moisture content of the films, and soil burial assessment showed less resistance to biodegradation. The morphological images presented a consistent structure and excellent compatibility between matrix and reinforcement, which reflected on the improved tensile strength and young modulus as well as the crystallinity index. The thermal stability of composite films has also been enhanced, as evidenced by the increased onset decomposition temperature of the reinforced films compared to neat film. Fourier transform infrared analysis revealed increasing in intermolecular hydrogen bonding following fiber loading. The composite materials prepared using corn husk residues as reinforcement responded to community demand for agricultural and polymeric waste disposal and added more value to waste management.
This study describes a sago starch-based film by incorporation of cinnamon essential oil (CEO) and nano titanium dioxide (TiO2-N). Different concentrations (i.e., 0%, 1%, 3%, and 5%, w/w) of TiO2-N and CEO (i.e., 0%, 1%, 2%, and 3%, v/w) were incorporated into sago starch film, and the physicochemical, barrier, mechanical, and antimicrobial properties of the bionanocomposite films were estimated. Incorporation of CEO into the sago starch matrix increased oxygen and water vapor permeability of starch films while increasing TiO2-N concentration decreased barrier properties. Moisture content also decreased from 12.96% to 8.04%, solubility in water decreased from 25% to 13.7%, and the mechanical properties of sago starch films improved. Sago starch bionanocomposite films showed excellent antimicrobial activity against Escherichia coli, Salmonella typhimurium, and Staphylococcus aureus. Results also showed that incorporation of TiO2-N and CEO had synergistic effects on functional properties of sago starch films. In summary, sago starch films incorporated with both TiO2-N and CEO shows potential application for active packaging in food industries such as fresh pistachio packaging.
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.
Polyhydroxyalkanoates (PHAs) are biodegradable polyesters produced by microorganisms, under unbalanced growth conditions, as a carbon storage compound. PHAs are composed of various monomers such as 3-hydroxybutyrate (3HB) and 3-hydroxyhexanoate (3HHx). Silk fibroin (SF) derived from Bombyx mori cocoons, is a widely studied protein polymer commonly used for biomaterial applications. In this study, non-woven electrospun films comprising a copolymer of 3HB and 3HHx [P(3HB-co-3HHx)], SF and their blends were prepared by electrospinning technique. The growth and osteogenic differentiation of human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) were studied using different types of fabricated electrospun films. The differentiation study revealed that electrospun P(3HB-co-3HHx)/SF film supports the differentiation of hUC-MSCs into the osteogenic lineage, confirmed by histological analysis using Alizarin Red staining, energy dispersive X-ray (EDX) and quantitative real-time PCR analysis (qPCR). Electrospun P(3HB-co-3HHx)/SF film up-regulated the expression of osteogenic marker genes, alkaline phosphatase (ALP) and osteocalcin (OCN), by 1.6-fold and 2.8-fold respectively, after 21 days of osteogenic induction. In conclusion, proliferation and osteogenic differentiation of hUC-MSCs were enhanced through the blending of P(3HB-co-3HHx) and SF. The results from this study suggest that electrospun P(3HB-co-3HHx)/SF film is a promising biomaterial for bone tissue engineering.
This study aimed to develop and characterize the calcium alginate films loaded with diclofenac sodium and other hydrophilic polymers with different degrees of cross-linking obtained by external gelation process. To the formed films different physicochemical evaluation were performed which showed an initial character of the films. The films produced by this external gelation process were found thicker (0.031-0.038 mm) and stronger (51.9-52.9 MPa) but less elastic (2.3%) than those non-cross-linked films (0.029 mm; 39.7 MPa; 4.4%). The lower water vapor permeability (WVP) values of the films were obtained where maximum level of crosslinking occurs. Composite films can be cross-linked in presence of external crosslinking agent to improve the quality of the produced matrices for various uses. The characterization of the film was performed using Differential Scanning Calorimetry (DSC) and Fourier-Transform Infrared Spectroscopy (FT-IR) analysis. The Scanning Electron Microscopy (SEM) study showed the morphology of treated composite films. The kinetic release studies showed a sustained release of the drug from the formulated films as it can be prolonged in composite film. The prepared biodegradable Ca-Alginate bio-composite film may be of clinical importance for its therapeutic benefit.
Arabinoxylan (AX) is a natural biological macromolecule with several potential biomedical applications. In this research, AX, nano-hydroxyapatite (n-HAp) and titanium dioxide (TiO2) based polymeric nanocomposite scaffolds were fabricated by the freeze-drying method. The physicochemical characterizations of these polymeric nanocomposite scaffolds were performed for surface morphology, porosity, swelling, biodegradability, mechanical, and biological properties. The scaffolds exhibited good porosity and rough surface morphology, which were efficiently controlled by TiO2 concentrations. MC3T3-E1 cells were employed to conduct the biocompatibility of these scaffolds. Scaffolds showed unique biocompatibility in vitro and was favorable for cell attachment and growth. PNS3 proved more biocompatible, showed interconnected porosity and substantial mechanical strength compared to PNS1, PNS2 and PNS4. Furthermore, it has also showed more affinity to cells and cell growth. The results illustrated that the bioactive nanocomposite scaffold has the potential to find applications in the tissue engineering field.
The objective of this study was to compare the morphological and chemical composition of bone graft (BG) and coral graft (CG) as well as their osteogenic differentiation potential using rabbit mesenchymal stem cells (rMSCs) in vitro. SEM analysis of BG and CG revealed that the pores in these grafts were interconnected, and their micro-CT confirmed pore sizes in the range of 107-315 µm and 103-514 µm with a total porosity of 92% and 94%, respectively. EDS analysis indicated that the level of calcium in CG was relatively higher than that in BG. FTIR of BG and CG confirmed the presence of functional groups corresponding to carbonyl, aromatic, alkyl, and alkane groups. XRD results revealed that the phase content of the inorganic layer comprised highly crystalline form of calcium carbonate and carbon. Atomic force microscopy analysis showed CG had better surface roughness compared to BG. In addition, significantly higher levels of osteogenic differentiation markers, namely, alkaline phosphatase (ALP), Osteocalcin (OC) levels, and Osteonectin and Runx2, Integrin gene expression were detected in the CG cultures, when compared with those in the BG cultures. In conclusion, our results demonstrate that the osteogenic differentiation of rMSCs is relatively superior in coral graft than in bone graft culture system.
In this work, biodegradable composites from poly(lactic acid) (PLA) and oil palm empty fruit bunch (OPEFB) fiber were prepared by melt blending method. Prior to mixing, the fiber was modified through bleaching treatment using hydrogen peroxide. Bleached fiber composite showed an improvement in mechanical properties as compared to untreated fiber composite due to the enhanced fiber/matrix interfacial adhesion. Interestingly, fiber bleaching treatment also improved the physical appearance of the composite. The study was extended by blending the composites with commercially available masterbatch colorant.
Polyimide/SiO(2) composite films were prepared from tetraethoxysilane (TEOS) and poly(amic acid) (PAA) based on aromatic diamine (4-aminophenyl sulfone) (4-APS) and aromatic dianhydride (3,3,4,4-benzophenonetetracarboxylic dianhydride) (BTDA) via a sol-gel process in N-methyl-2-pyrrolidinone (NMP). The prepared polyimide/SiO(2) composite films were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and thermogravimetric analysis (TGA). The FTIR results confirmed the synthesis of polyimide (4-APS/BTDA) and the formation of SiO(2) particles in the polyimide matrix. Meanwhile, the SEM images showed that the SiO(2) particles were well dispersed in the polyimide matrix. Thermal stability and kinetic parameters of the degradation processes for the prepared polyimide/SiO(2) composite films were investigated using TGA in N(2) atmosphere. The activation energy of the solid-state process was calculated using Flynn-Wall-Ozawa's method without the knowledge of the reaction mechanism. The results indicated that thermal stability and the values of the calculated activation energies increased with the increase of the TEOS loading and the activation energy also varied with the percentage of weight loss for all compositions.
One of the ultimate goals of wound healing research is to find effective healing techniques that utilize the regeneration of similar tissues. This involves the modification of various wound dressing biomaterials for proper wound management. The biopolymer chitosan (beta-1,4-D-glucosamine) has natural biocompatibility and biodegradability that render it suitable for wound management. By definition, a biocompatible biomaterial does not have toxic or injurious effects on biological systems. Chemical and physical modifications of chitosan influence its biocompatibility and biodegradability to an uncertain degree. Hence, the modified biomedical-grade of chitosan derivatives should be pre-examined in vitro in order to produce high-quality, biocompatible dressings. In vitro toxicity examinations are more favorable than those performed in vivo, as the results are more reproducible and predictive. In this paper, basic in vitro tools were used to evaluate cellular and molecular responses with regard to the biocompatibility of biomedical-grade chitosan. Three paramount experimental parameters of biocompatibility in vitro namely cytocompatibility, genotoxicity and skin pro-inflammatory cytokine expression, were generally reviewed for biomedical-grade chitosan as wound dressing.
Cell adhesion is essential in cell communication and regulation, and is of fundamental importance in the development and maintenance of tissues. The mechanical interactions between a cell and its extracellular matrix (ECM) can influence and control cell behavior and function. The essential function of cell adhesion has created tremendous interests in developing methods for measuring and studying cell adhesion properties. The study of cell adhesion could be categorized into cell adhesion attachment and detachment events. The study of cell adhesion has been widely explored via both events for many important purposes in cellular biology, biomedical, and engineering fields. Cell adhesion attachment and detachment events could be further grouped into the cell population and single cell approach. Various techniques to measure cell adhesion have been applied to many fields of study in order to gain understanding of cell signaling pathways, biomaterial studies for implantable sensors, artificial bone and tooth replacement, the development of tissue-on-a-chip and organ-on-a-chip in tissue engineering, the effects of biochemical treatments and environmental stimuli to the cell adhesion, the potential of drug treatments, cancer metastasis study, and the determination of the adhesion properties of normal and cancerous cells. This review discussed the overview of the available methods to study cell adhesion through attachment and detachment events.
An ideal scaffold should be biocompatible, having appropriate microstructure, excellent mechanical strength yet degrades. Chitosan exhibits most of these exceptional properties, but it is always associated with sub-optimal cytocompatibility. This study aimed to incorporate graphene oxide at wt % of 0, 2, 4, and 6 into chitosan matrix via direct blending of chitosan solution and graphene oxide, freezing, and freeze drying. Cell fixation, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide, alkaline phosphatase colorimetric assays were conducted to assess cell adhesion, proliferation, and early differentiation of MG63 on chitosan-graphene oxide scaffolds respectively. The presence of alkaline phosphatase, an early osteoblast differentiation marker, was further detected in chitosan-graphene oxide scaffolds using western blot. These results strongly supported that chitosan scaffolds loaded with graphene oxide at 2 wt % mediated cell adhesion, proliferation, and early differentiation due to the presence of oxygen-containing functional groups of graphene oxide. Therefore, chitosan scaffolds loaded with graphene oxide at 2 wt % showed the potential to be developed into functional bone scaffolds.