Maghemite (γ-Fe2O3) nanoparticle with its unique magnetic properties is recently known to enhance the cell growth rate. In this study, γ-Fe2O3 is mixed into polyvinyl alcohol (PVA) matrix and then electrospun to form nanofibers. Design of experiments was used to determine the optimum parameter settings for the electrospinning process so as to produce elctrospun mats with the preferred characteristics such as good morphology, Young's modulus and porosity. The input factors of the electrospinnning process were nanoparticles content (1-5%), voltage (25-35 kV), and flow rate (1-3 ml/h) while the responses considered were Young's modulus and porosity. Empirical models for both responses as a function of the input factors were developed and the optimum input factors setting were determined, and found to be at 5% nanoparticle content, 35 kV voltage, and 1 ml/h volume flow rate. The characteristics and performance of the optimum PVA/γ-Fe2O3 nanofiber mats were compared with those of neat PVA nanofiber mats in terms of morphology, thermal properties, and hydrophilicity. The PVA/γ-Fe2O3 nanofiber mats exhibited higher fiber diameter and surface roughness yet similar thermal properties and hydrophilicity compared to neat PVA PVA/γ-Fe2O3 nanofiber mats. Biocompatibility test by exposing the nanofiber mats with human blood cells was performed. In terms of clotting time, the PVA/γ-Fe2O3 nanofibers exhibited similar behavior with neat PVA. The PVA/γ-Fe2O3 nanofibers also showed higher cells proliferation rate when MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was done using human skin fibroblast cells. Thus, the PVA/γ-Fe2O3 electrospun nanofibers can be a promising biomaterial for tissue engineering scaffolds.
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.
Recombinant vitronectin-grafted hydrogels were developed by adjusting surface charge of the hydrogels with grafting of poly-l-lysine for optimal culture of human embryonic stem cells (hESCs) under xeno- and feeder-free culture conditions, with elasticity regulated by crosslinking time (10-30 kPa), in contrast to conventional recombinant vitronectin coating dishes, which have a fixed stiff surface (3 GPa). hESCs proliferated on the hydrogels for over 10 passages and differentiated into the cells derived from three germ layers indicating the maintenance of pluripotency. hESCs on the hydrogels differentiated into cardiomyocytes under xeno-free culture conditions with much higher efficiency (80% of cTnT+ cells) than those on conventional recombinant vitronectin or Matrigel-coating dishes just only after 12 days of induction. It is important to have an optimal design of cell culture biomaterials where biological cues (recombinant vitronectin) and physical cues (optimal elasticity) are combined for high differentiation of hESCs into specific cell lineages, such as cardiomyocytes, under xeno-free and feeder-free culture conditions.
In this report, we demonstrate that continuous improvement in XPS instruments and the calibration standards as well
as analysis with standard component-fitting procedures can be used to determine the binding energies of compounds
containing phosphorus and sulfur of different oxidation states with higher confidence. Based on such improved XPS
analyses, the binding energies (BEs) of S2p signals for sulfur of increasing oxidation state are determined to be 166-167.5
eV for S=O in dimethyl sulfoxide, 168.1 eV for S=O2
in polysulfone, 168.4 eV for SO3
in polystyrene sulfonate and 168.8
eV for SO4
in chondroitin sulfate. The BEs of P2p signals show the following values: 132.9 eV for PO3
phosphite, 133.3 eV for PO4
in glycerol phosphate, 133.5 eV for PO4
in sodium tripolyphosphate and 134.0 eV for PO4
in sodium hexametaphosphate. These results showed that there are only small increases in the binding energy when
additional oxygen atoms are added to the S-O chemical group. A similar result is obtained when the fourth oxygen or
poly-phosphate environment is added to the phosphorus compound. These BE values are useful to researchers involved
in identifying oxidation states of phosphorus and sulfur atoms commonly observed on modified surfaces and interfaces
found in applications such as biomaterials, super-capacitors and catalysis.
Immediate control of uncontrolled bleeding and infection are essential for saving lives in both combat and civilian arenas. Inorganic well-ordered mesoporous silica and bioactive glasses have recently shown great promise for accelerating hemostasis and infection control. However, to date, there has been no comprehensive report assessing their specific mechanism of action in accelerating the hemostasis process and exerting an antibacterial effect. After providing a brief overview of the hemostasis process, this review presents a critical overview of the recently developed inorganic mesoporous silica and bioactive glass-based materials proposed for hemostatic clinical applications and specifically investigates their unique characteristics that render them applicable for hemostatic applications and preventing infections. This article also identifies promising new research directions that should be undertaken to ascertain the effectiveness of these materials for hemostatic applications.
Global issues such as environmental problems and food security are currently of concern to all of us. Circular bioeconomy is a promising approach towards resolving these global issues. The production of bioenergy and biomaterials can sustain the energy-environment nexus as well as substitute the devoid of petroleum as the production feedstock, thereby contributing to a cleaner and low carbon environment. In addition, assimilation of waste into bioprocesses for the production of useful products and metabolites lead towards a sustainable circular bioeconomy. This review aims to highlight the waste biorefinery as a sustainable bio-based circular economy, and, therefore, promoting a greener environment. Several case studies on the bioprocesses utilising waste for biopolymers and bio-lipids production as well as bioprocesses incorporated with wastewater treatment are well discussed. The strategy of waste biorefinery integrated with circular bioeconomy in the perspectives of unravelling the global issues can help to tackle carbon management and greenhouse gas emissions. A waste biorefinery-circular bioeconomy strategy represents a low carbon economy by reducing greenhouse gases footprint, and holds great prospects for a sustainable and greener world.
Design of blood compatible surfaces is obligatory to minimize platelet surface interactions and improve the thromboresistance of foreign surfaces when they are utilized as biomaterials particularly for blood contacting devices. Pure metallocene polyethylene (mPE) and nitric acid (HNO3) treated mPE antithrombogenicity and hydrophilicity were investigated. The contact angle of the mPE treated with HNO3 decreased. Surface of mPE and HNO3 treated mPE investigated with FTIR revealed no major changes in its functional groups. 3D Hirox digital microscopy, SEM and AFM images show increased porosity and surface roughness. Blood coagulation assays prothrombin time (PT) and activated partial thromboplastin time (APTT) were delayed significantly (P < 0.05) for HNO3 treated mPE. Hemolysis assay and platelet adhesion of the treated surface resulted in the lysis of red blood cells and platelet adherence, respectively indicating improved hemocompatibility of HNO3 treated mPE. To determine that HNO3 does not deteriorate elastic modulus of mPE, the elastic modulus of mPE and HNO3 treated mPE was compared and the result shows no significant difference. Hence, the overall observation suggests that the novel HNO3 treated mPE may hold great promises to be exploited for blood contacting devices like grafts, catheters, and etc.
A poly(vinyl alcohol) (PVA) hydrogel composite scaffold containing N,O-carboxymethylated chitosan (NOCC) was tested to assess its potential as a scaffold for cartilage tissue engineering in a weight-bearing environment. The mechanical properties under unconfined compression for different hydration periods were investigated. The effect of supplementing PVA with NOCC (20wt.% PVA:5vol.% NOCC) produced a porosity of 43.3% and this was compared against a non-porous PVA hydrogel (20g PVA: 100ml of water, control). Under non-hydrated conditions, the porous PVA-NOCC hydrogel behaved in a similar way to the control non-porous PVA hydrogel, with similar non-linear stress-strain response under unconfined compression (0-30% strain). After 7days' hydration, the porous hydrogel demonstrated a reduced stiffness (0.002kPa, at 25% strain), resulting in a more linear stiffness relationship over a range of 0-30% strain. Poisson's ratio for the hydrated non-porous and porous hydrogels ranged between 0.73 and 1.18, and 0.76 and 1.33, respectively, suggesting a greater fluid flow when loaded. The stress relaxation function for the porous hydrogel was affected by the hydration period (from 0 to 600s); however the percentage stress relaxation regained by about 95%, after 1200s for all hydration periods assessed. No significant differences were found between the different hydration periods between the porous hydrogels and control. The calculated aggregate modulus, H(A), for the porous hydrogel reduced drastically from 10.99kPa in its non-hydrated state to about 0.001kPa after 7days' hydration, with the calculated shear modulus reducing from 30.92 to 0.14kPa, respectively. The porous PVA-NOCC hydrogel conformed to a biphasic, viscoelastic model, which has the desired properties required for any scaffold in cartilage tissue engineering.
Recent progress on highly tough and stretchable polymer networks has highlighted the potential of wearable electronic devices and structural biomaterials such as cartilage. For some given applications, a combination of desirable mechanical properties including stiffness, strength, toughness, damping, fatigue resistance, and self-healing ability is required. However, integrating such a rigorous set of requirements imposes substantial complexity and difficulty in the design and fabrication of these polymer networks, and has rarely been realized. Here, we describe the construction of supramolecular polymer networks through an in situ copolymerization of acrylamide and functional monomers, which are dynamically complexed with the host molecule cucurbituril (CB). High molecular weight, thus sufficient chain entanglement, combined with a small-amount dynamic CB-mediated non-covalent crosslinking (2.5 mol%), yields extremely stretchable and tough supramolecular polymer networks, exhibiting remarkable self-healing capability at room temperature. These supramolecular polymer networks can be stretched more than 100× their original length and are able to lift objects 2000× their weight. The reversible association/dissociation of the host-guest complexes bestows the networks with remarkable energy dissipation capability, but also facile complete self-healing at room temperature. In addition to their outstanding mechanical properties, the networks are ionically conductive and transparent. The CB-based supramolecular networks are synthetically accessible in large scale and exhibit outstanding mechanical properties. They could readily lead to the promising use as wearable and self-healable electronic devices, sensors and structural biomaterials.
Titanium (Ti) and Ti-based alloys presence the most widely applied as advanced biomaterials
in biomedical implant applications. Moreover, these alloys are known to be the most
valuable metallic materials including spinal cord surgical treatment. It becomes an interest
due to its advantages compared to others, including its bio compatibility and corrosion
resistant. However, an issue arises when it comes for permanent implant application as
the alloy has a possible toxic effect produced from chemical reaction between body fluid
environments with alloys chemical compositions. It also relies on the performance of
neighbouring bone tissue to integrate with the implant surface. Abnormalities usually
happen when surrounding tissue shows poor responses and rejection of implants that would
leads to body inflammation. These cause an increase in foreign body reaction leading to
severe body tissue response and thus, loosening of the implant. Corrosion effects and
biocompatibility behaviour of implantation usage also become one of the reasons of
implant damage. Here, this paper reviews the importance of using Ti and Ti-based alloys
in biomedical implantation, especially in orthopaedic spinal cord injury. It also reviews the
basic aspects of corrosion effects that lead to implant mechanical damage, poor response
of body rejection and biocompatibility behaviour of implantation usage.
Tracheal replacement is performed after resection of a portion of the trachea that was impossible to reconnect via direct anastomosis. A tissue-engineered trachea is one of the available options that offer many advantages compared to other types of graft. Fabrication of a functional tissue-engineered trachea for grafting is very challenging, as it is a complex organ with important components, including cartilage, epithelium and vasculature. A number of studies have been reported on the preparation of a graftable trachea. A laterally rigid but longitudinally flexible hollow cylindrical scaffold which supports cartilage and epithelial tissue formation is the key element. The scaffold can be prepared via decellularization of an allograft or fabricated using biodegradable or non-biodegradable biomaterials. Commonly, the scaffold is seeded with chondrocytes and epithelial cells at the outer and luminal surfaces, respectively, to hasten tissue formation and improve functionality. To date, several clinical trials of tracheal replacement with tissue-engineered trachea have been performed. This article reviews the formation of cartilage tissue, epithelium and neovascularization of tissue-engineered trachea, together with the obstacles, possible solutions and future. Furthermore, the role of the bioreactor for in vitro tracheal graft formation and recently reported clinical applications of tracheal graft were also discussed. Generally, although encouraging results have been achieved, however, some obstacles remain to be resolved before the tissue-engineered trachea can be widely used in clinical settings.
A novel decellularization method using sonication treatment is described. Sonication treatment is the combination of physical and chemical agents. These methods will disrupt cell membrane and release cell contents to external environments. The cell removal was facilitated by subsequent rinsing of sodium dodecyl sulfate detergents. Sonication treatment is used in the preparation of complete decellularized bioscaffolds. The aim of this study is to confirm the usefulness of sonication treatment for preparation of biological scaffolds. In this study, samples of aortic tissues are decellularized by sonication treatment at frequency of 170 kHz in 0.1% and 2% sodium dodecyl sulfate detergents for 10-h treatment time. The relation between decellularization and sonication parameters such as dissolved oxygen concentration, conductivity, and pH is investigated. Histological analysis and biomechanical testing is performed to evaluate cell removal efficiency as well as changes in biomechanical properties. Minimal inflammation response elicit by bioscaffolds is confirmed by xenogeneic implantation and immunohistochemistry. Sonication treatment is able to produce complete decellularized tissue suggesting that these treatments could be applied widely as one of the decellularization method.
To avoid tissue rejection during organ transplantation, research has focused on the use of tissue engineering to regenerate required tissues or organs for patients. The biomedical applications of hyperbranched, multivalent, structurally uniform, biocompatible dendrimers in tissue engineering include the mimicking of natural extracellular matrices (ECMs) in the 3D microenvironment. Dendrimers are unimolecular architects that can incorporate a variety of biological and/or chemical substances in a 3D architecture to actively support the scaffold microenvironment during cell growth. Here, we review the use of dendritic delivery systems in tissue engineering. We discuss the available literature, highlighting the 3D architecture and preparation of these nanoscaffolds, and also review challenges to, and advances in, the use dendrimers in tissue engineering. Advances in the manufacturing of dendritic nanoparticles and scaffold architectures have resulted in the successful incorporation of dendritic scaffolds in tissue engineering.
Maintenance of oral health is a major challenge in dentistry. Different materials have been used to treat various dental diseases, although treatment success is limited by features of the biomaterials used. To overcome these limitations, materials incorporated with nanoparticles (NPs) can be used in dental applications including endodontics, periodontics, tissue engineering, oral surgery, and imaging. The unique properties of NPs, including their surface:volume ratio, antibacterial action, physical, mechanical, and biological characteristics, and unique particle size have rendered them effective vehicles for dental applications. In this review, we provide insights into the various applications of NPs in dentistry, including their benefits, limitations, properties, actions and future potential.
Introduction: Oral cancer is the sixth most common malignancy in the world. It is a major concern in Southeast Asia primarily due to betel quid chewing, smoking, and alcohol consumption. In Malaysia, oral cancer related cases accounts for 1.55% of the cause of deaths. Despite recent advances in cancer diagnoses and therapies, the survival rate of oral cancer patients only reached 50% in the last few decades. Tissue engineering (TE) principles may pro-vide new technology platforms to study mechanisms of angiogenesis and tumour cell growth as well as potentially tumour cell spreading in cancer research. The use of biomaterial, appropriate cell source and proper signalling mol-ecules are vital components of TE. Collagen biomaterial are widely used scaffold or membrane in oral application. Nevertheless, no review has been performed on the its usage for the study of oral cancer. This study aimed to sys-tematically review the use of collagen scaffold in oral cancer application. Methods: Research articles were searched using Scopus, Pubmed and Web of Science (WOS) databases. The keywords were limited to “collagen membrane OR collagen scaffold” AND “oral cancer”. Results: Initial search yielded 61 papers (Scopus:37, Pubmed: 12, WOS: 12). Further scrutinization of the papers based on the inclusion criteria resulted total of 3 papers. Two of the papers used collagen membrane for regeneration of oral mucosal defect and increment of alveolar ridge height post-surgery. The remaining paper utilize collagen biomaterial as scaffold for the culture of adenoid cystic carcinoma (ACC) cells. All papers reported significant role of collagen biomaterial in terms of tissue formation, healing scaffold and cellular proliferation. Conclusion: Collagen utilization as biomaterial offers potential use for regeneration of oral related structures as well providing useful model for therapeutics anti-cancer research.
Hydroxyapatite (HA) has been earmarked as suitable for implantation within the human of its chemical makeup to human bone. In this paper, HA powders were synthesized via the precipitation method where phosphoric acid (H3PO4) was titrated into calcium hydroxide solution [Ca(OH)2]. Two parameters such as temperature and stirring rate were identified as factors that influenced the amount and purity of HA powder. Phase identification of the synthesized powder was done using X-Ray Diffraction (XRD). The results show that HA phase can be synthesized from this titration process of Ca(OH)2 and H3PO4 with yield amount of HA powder around 45 - 61 grams but with less than hundred percent purity. In order to study the effect of heat treatment to HA crystals structure, HA powder was calcined at 850 degrees C for 2 hours. It's found that the degree of crystallinity increases after calcination because of lattice expansion when the materials were heated at higher temperature
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.
The aim of the present study was to test the hypothesis that the proliferation of a human osteoblast cell line (HOS cells) stimulated with hydroxyapatite (HA) may be regulated by nitric oxide (NO). The cells were cultured on the surface of HA. Medium or cells alone were used as controls. L-arginine, D-arginine, 7-NI (an nNOS inhibitor), L-NIL (an iNOS inhibitor), L-NIO (an eNOS inhibitor) or carboxy PTIO, a NO scavenger, was added in the HA-exposed cell cultures. The cells were also precoated with anti-human integrin alphaV antibody. The levels of nitrite were determined spectrophotometrically. Cell proliferation was assessed by colorimetric assay. The results showed increased nitrite production and cell proliferation by HA-stimulated HOS cells up to day 3 of cultures. Anti-integrin alphaV antibody, L-NIO, or carboxy PTIO suppressed, but L-arginine enhanced, nitrite production and cell proliferation of HA-stimulated HOS cells. The results of the present study suggest, therefore, that interaction between HA and HOS cell surface integrin alphaV molecule may activate eNOS to catalyze NO production which, in turn, may regulate the cell proliferation in an autocrine fashion.
Dendrimers are hyperbranched nanoparticle structures along with its surface modifications can to be used in dental biomaterials for biomimetic remineralisation of enamel and dentin. The review highlights the therapeutic applications of dendrimers in the field of dentistry. It addresses the possible mechanisms of enhancement of mechanical properties of adhesives and resins structure. Dendrimers due to its unique construction of possessing inner hydrophobic and outer hydrophilic structure can act as drug carrier for delivery of antimicrobial drugs for treatment of periodontal diseases and at peripheral dental implant areas. Dendrimers due to its hyperbranched structures can provides a unique drug delivery vehicle for delivery of a drug at specific site for sustained release for therapeutic effects. Thus, dendrimers can be one of the most important constituents which can be incorporated in dental biomaterials for better outcomes in dentistry.