A screen-printed carbon electrode modified with gold nanoparticles, poly(3,4-ethylenedioxythiophene), poly(styrene sulfonate) and a molecular imprint for voltammetric determination of nitrofurantoin.

A molecularly imprinted polymer (MIP) and a nanocomposite prepared from gold nanoparticles (AuNP) and poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) (PEDOT:PSS) were deposited on a screen-printed carbon electrode (SPCE). The nanocomposite was prepared by one-pot simultaneous in-situ formation of AuNPs and PEDOT:PSS and was then inkjet-coated onto the SPCE. The MIP film was subsequently placed on the modified SPCE by co-electrodeposition of o-phenylenediamine and resorcinol in the presence of the antibiotic nitrofurantoin (NFT). Using differential pulse voltammetry (DPV), response at the potential of ~ 0.1 V (vs. Ag/AgCl) is linear in 1 nM to 1000 nM NFT concentration range, with a remarkably low detection limit (at S/N = 3) of 0.1 nM. This is two orders of magnitude lower than that of the control MIP sensor without the nanocomposite interlayer, thus showing the beneficial effect of AuNP-PEDOT:PSS. The electrode is highly reproducible (relative standard deviation 3.1% for n = 6) and selective over structurally related molecules. It can be re-used for at least ten times and was found to be stable for at least 45 days. It was successfully applied to the determination of NFT in (spiked) feed matrices and gave good recoveries. Graphical abstract Schematic representation of a voltammetric sensor for the determination of nitrofurantoin. The sensor is based on a screen-printed carbon electrode (SPCE) modified with an inkjet-printed gold nanoparticles-poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) nanocomposite and a molecularly imprinted polymer.

Magnetic and morphological properties of CoCu nanowires.

Heterogeneous CoCu nanowires containing different amounts of Co (up to 50% at. wt of Co) are made by electro-deposition (ED) method. CoCu nanowires were grown in AAO templates by varying the current density. The diameter of CoCu nanowires was around 40 nm. Therefore, the growing of CoCu nanowires was compacted with the diameter of AAO templates. The XRD patterns showed that all the CoCu nanowires fabricated via electro-deposition were polycrystalline. At low current density (1.32 mA/cm2), the intensity of Cu (111) peak was very strong. Increasing the current density can be led to increase the intensity of Co (100) peak. High resolution transmission electron microscopy (HRTEM) images of the highest Co content (50%at.) wires showed the existence of layers of polycrystalline heterogeneous CoCu alternating with layers of Cu. The magnetic properties showed that the highest coercivity (7.235 kOe) and squareness (0.754) were found in the unannealed nanowires having the highest Co content.

Copper Zinc Sulfide (CuZnS) Quantum Dot-Decorated (NiCo)-S/Conductive Carbon Matrix as the Cathode for Li-S Batteries.

Sulfur composites consisting of electrochemical reactive catalysts/conductive materials are investigated for use in lithium-sulfur (Li-S) batteries (LSBs). In this paper, we report the synthesis, physicochemical and electrochemical properties of CuZnS quantum dots (CZSQDs) decorated with nickel-cobalt-sulfide ((NiCo)-S)) mixed with reduced graphene oxide (rGO)/oxidized carbon nanotube (oxdCNT) (rGO/oxdCNT) ((NiCo)-S@rGO/oxdCNT) composites. These composites are for the purpose of being the sulfur host cathode in Li-S batteries. The as-prepared composites showed a porous structure with the CZSQDs being uniformly found on the surface of the rGO/oxdCNT, which had a specific surface area of 26.54 m2/g. Electrochemical studies indicated that the (NiCo)-S@rGO/oxdCNT cells forming the cathode exhibited a maximum capacity of 1154.96 mAhg-1 with the initial discharge at 0.1 C. The smaller size of the CZSQDs (~10 nm) had a positive effect on the CZSQDs@(NiCo)-S@rGO/oxdCNT composites in that they had a higher initial discharge capacity of 1344.18 mAhg-1 at 0.1 C with the Coulombic efficiency being maintained at almost 97.62% during cycling. This latter property is approximately 1.16 times more compared to the absence of the Cu-Zn-S QD loading. This study shows that the CuZnS quantum dots decorated with a (NiCo)-S@rGO/oxdCNT supporting matrix-based sulfur cathode have the potential to improve the performance of future lithium-sulfur batteries.

Fabrication of biocompatible magneto-fluorescence nanoparticles as a platform for fluorescent sensor and magnetic hyperthermia applications.

Multifunctional nanoparticles with special magnetic and optical properties have been attracting a great deal of attention due to their important applications in the bioanalytical and biomedical fields. In this study, we report the fabrication of biocompatible magneto-fluorescence nanoparticles consisting of carbon dots (CDots) and silica-coated cobalt-manganese nanoferrites (Co0.5Mn0.5Fe2O4) (CoMnF@Si@CDots) (MagSiCDots) by a facile hydrothermal method. The as-prepared MagSiCDots have a particle size of 100-120 nm and show a negative zeta potential of -35.50 mV at a neutral pH. The fluorescence spectrum of the MagSiCDots nanoparticles consists of sharp excitation at 365 nm and broad blue light emission with a maximum wavelength of 442.5 nm and the MagSiCDots exhibit superparamagnetic behaviour with a saturation magnetization of 11.6 emu g-1. The potential of MagSiCDots as a fluorescent sensor and be used for magnetic hyperthermia applications. It is seen that the fluorescent intensity of a colloidal solution (a hydrogen sulfide (H2S) solution containing MagSiCDots nanoparticles) has a linear relationship with the H2S concentration range of 0.2-2 µM. The limit of detection (LOD) of H2S by our MagSiCDots particles is 0.26 µM and they remain stable for at least 90 min. To test the suitability of the MagSiCDots nanoparticles for use in hyperthermia application, induction heating using an AMF was done. It was observed that these nanoparticles had a specific absorption rate (SAR) of 28.25 W g-1. The in vitro and in vivo cytotoxicity of MagSiCDots were tested on HeLa cells lines. The results show a cell viability of about 85% when exposed to 100 µg mL-1 concentration of the particles. The in vivo cytotoxicity using zebrafish assay also confirmed the non-toxicity and biocompatibility of the nanoparticles to living cells. The reported data demonstrate that by combining CoMnF@Si and fluorescent CDots into a single system, not only nontoxic multifunctional nanomaterials but also multimodal nanoparticles for several applications, such as hazard gas detection and acting as a biocompatible heat source for therapeutic treatment of cancer, are provided.

Hyperthermia evaluation and drug/protein-controlled release using alternating magnetic field stimuli-responsive Mn-Zn ferrite composite particles.

Drug delivery particles in which the release of biomolecules is triggered by a magnetic simulant have attracted much attention and may have great potential in the fields of cancer therapy and tissue regenerative medicine. In this study, we have prepared magnetic Mn-Zn ferrite ((Mn,Zn)Fe2O4) (MZF) nanoparticles coated with chitosan-g-N-isopropylacrylamide (Chi-g-NIPAAm) polymer (MZF@Chi-g-NIPAAm) to deliver the anticancer drug (Doxorubicin, DOX) and bioactive proteins (Bone morphogenic protein (BMP-2)-immobilized bovine serum albumin (BSA)) (P//MZF@Chi-g-NIPAAm) and be used as chemo-hyperthermia and vector delivering biomolecules. For these purposes, we first show that the as-prepared MZF@Chi-g-NIPAAm particles exhibit super paramagnetic behavior and under certain conditions, they can act as a heat source with a specific absorption rate (SAR) of 34.88 W g-1. Under acidic conditions and in the presence of AMF, the fast release of DOX was seen at around 58.9% within 20 min. In vitro evaluations indicated that concurrent thermo-chemotherapy treatment by DOX-MZF@Chi-g-NIPAAm using AMF had a better antitumor effect, compared with those using either DOX or DOX-MZF@Chi-g-NIPAAm without AMF (89.02% of cells were killed as compared to 71.82% without AMF exposure). Up to 28.18% of the BSA (used as the model protein to determine the controlled release) is released from the P//MZF@Chi-g-NIPAAm particles under AMF exposure for 1 h (only 17.31% was released without AMF). These results indicated that MZF@Chi-g-NIPAAm particles could be used to achieve hyperthermia at a precise location, effectively enhancing the chemotherapy treatments, and have a promising future as drug or bioactive delivering molecules for cancer treatment and cartilage or bone regenerative applications.

Effect of silver doping on antidiabetic and antioxidant potential of ZnO nanorods.

BACKGROUND: Increasing resistance to available drugs and their associated side-effects have drawn wide attention towards designing alternative therapeutic strategies for control of hyperglycemia and oxidative stress. The roles of the sizes and shapes of the nanomaterials used in the treatment and management of Type 2 Diabetes Mellitus (T2DM) in preventing chronic hyperglycaemia and oxidative stress are investigated. We report specifically on the effects of doping silver (Ag) into the ZnO nanorods (ZnO:Ag NR's) as a rational drug designing strategy. METHODS: Inhibition of porcine pancreatic α-amylase, murine pancreatic amylase, α-glucosidase, murine intestinal glucosidase and amyloglucosidase are checked for evaluation of antidiabetic potential. In addition, the radical scavenging activities of ZnO:Ag NR's against nitric oxide, DDPH and superoxide radicals are evaluated. RESULTS: Quantitative radical scavenging and metabolic enzyme inhibition activities of ZnO:Ag NR's at a concentration of 100 µg/mL were found to depend on the amount of Ag doped in up to a threshold level (3-4 %). Circular dichroism analysis revealed that the interaction of the NR's with the enzymes altered their secondary conformation. This alteration is the underlying mechanism for the potent enzyme inhibition. CONCLUSIONS: Enhanced inhibition of enzymes and scavenging of free radicals primarily responsible for reactive oxygen species (ROS) mediated damage, provide a strong scientific rationale for considering ZnO:Ag NR's as a candidate nanomedicine for controlling postprandial hyperglycaemia and the associated oxidative stress.

Salivary Creatinine Detection Using a Cu(I)/Cu(II) Catalyst Layer of a Supercapacitive Hybrid Sensor: A Wireless IoT Device To Monitor Kidney Diseases for Remote Medical Mobility.

The stress-free electrochemical-based sensor equipped with the Internet of Things (IoT) device for salivary creatinine determination was fabricated for point-of-care (POC) diagnosis of advanced kidney disorders. Beneficial and real-time data readout for preventive diagnosis and clinical evaluation of chronic kidney diseases (CKD) at different stages and renal dysfunction can be acquired by noninvasive monitoring of the creatinine amounts in saliva. The direct determination and real-time response of salivary creatinine can be attained using the supercapacitor-based sensor of cuprous oxide nanoparticles entrapped by the synergistically cross-linked poly(acrylic acid) (PAA) gel-Cu2+ and Nafion perfluorinated membrane fabricated on a screen-printed carbon electrode (SPCE). Here, we demonstrated that the degree of renal illness could be evaluated using salivary creatinine detection via a catalytic mechanism as Cu2+ ions bound irreversibly with C═N functional groups of creatinine. Besides, the computer simulation was performed to study the interaction between 5 functional groups of creatinine toward acrylic gel-Cu2+. The linear increment between the obtained anodic currents and creatinine concentrations varying from 1 to 2000 µM was accomplished with a selectivity efficiency of 97.2%. Nyquist plots obtained by electrochemical impedance spectroscopy (EIS) validated that the increment of impedance changes strongly dependent on the amount of detected creatinine both in artificial and in human saliva. The porosity features were observed in this interconnected nanocomposite and correlated with Nafion doping. Successively, the friendly portable device was invented and integrated saliva sampling with miniaturized, low-cost IoT electronics of world-location mapping, representing the first remote medical sensor focusing on salivary creatinine sensing.

Evidence of Cu(I) Coupling with Creatinine Using Cuprous Nanoparticles Encapsulated with Polyacrylic Acid Gel-Cu(II) in Facilitating the Determination of Advanced Kidney Dysfunctions.

An electrochemical-based sensor created for creatinine detection has been developed for early point-of-care (POC) of diagnosis of renal illnesses. Useful information for the preventive diagnosis and clinical treatments of congenital disorders of creatinine mechanism, advanced liver and kidney diseases, and renal dysfunction can be obtained by the noninvasive evaluation of the creatinine levels in urine. The direct detection of creatinine can be achieved using the modified nanocomposite of cuprous nanoparticles encapsulated by polyacrylic acid (PAA) gel-Cu(II) fabricating on a screen-printed carbon electrode. Here, we report that the degree of kidney dysfunction failure can be determined by an amount of Cu(I) bound with the creatinine through the adsorptive mechanism on the modified electrode. Under cyclic voltammetry scans, the amount of creatinine was measured from the adsorptive signals of the redox peak current identifying the Cu(I)-creatinine complex with a natural logarithm of the creatinine concentration ranging from 200 µM to 100 mM. For this detection range, the theoretical calculation was postulated to describe experimental behaviors of the adsorptive mechanism as creatinine diffused to adsorb on the composite-modified electrode to reduce oxidized copper nanoparticles and transformed to Cu(II)-creatinine complexes. Interestingly, there was evidence that anodic peak potentials had been reduced in magnitudes and shifted negatively by natural logarithm during the formation of the Cu(I)-creatinine complex. For practical usage in POC technology, the creatinine detection in interference was carried out using differential pulse voltammetry to solely determine faradaic currents of creatinine-copper formation. With the interference of urea, glucose, ascorbic acid, glycine, and uric acid in artificial urine, the sensor showed promising results of the interference-free determination with 99.4% sensitivity efficiency, whereas for human urine interference, this sensor showed 85% sensitivity efficiency in detecting creatinine. This shows that this composite-modified sensor (PAA gel-Cu(II)/Cu2O NPs) has great potential for use in the next-generation devices for creatinine sensing to determine the progression in kidney dysfunctions.

Effect of zirconia-mullite incorporated biphasic calcium phosphate/biopolymer composite scaffolds for bone tissue engineering.

New bioactive scaffolds with improved mechanical properties, biocompatibility and providing structural support for bone tissue are being developed for use in the treatment of bone defects. In this study, we have synthesized bioactive scaffolds consisting of biphasic calcium phosphate (BCP) and zirconia-Mullite (2ZrO2·[3Al2O3 ·2 SiO2] (ZAS)) (BCPZAS) combined with polymers matrix of polycaprolactone (PCL)-alginate (Alg)-chitosan (Chi) (Chi/Alg-PCL) (BCPZAS@Chi/Alg-PCL). The composite material scaffolds were prepared by a blending technique. The microstructure, mechanical, bioactivity and in vitro biological properties with different ratios of BCP to ZAS of 1:0, 3:1, 1:1, 1:3 and 0:1 wt% in polymer matrix were analyzed. Microstructure analysis showed a successful incorporation of the BCPZAS particles with an even distribution of them within the polymer matrix. The mechanical properties were found to gradually decrease with increasing the ratio of ZAS particles in the scaffolds. The highest compressive strength was 42.96 ± 1.01MPa for the 3:1 wt% BCP to ZAS mixing. Bioactivity test, the BCPZAS@Chi/Alg-PCL composite could induce apatite formation in simulate body fluid (SBF). In-vitro experiment using UMR-106 osteoblast-like cells on BCPZAS@Chi/Alg-PCL composite scaffold showed that there is cell attachment to the scaffolds with proliferation. These experimental results demonstrate that the BCPZAS@Chi/Alg-PCL composite especially for the BCP:ZAS at 3:1 wt% could be utilized as a scaffold for bone tissue engineering applications.

Investigation of magnetic silica with thermoresponsive chitosan coating for drug controlled release and magnetic hyperthermia application.

In this study, a drug delivery system for chemo-hyperthermia applications is proposed and fabricated. The delivery system consists of magnetic-silica (MagSi) particles being encapsulated within a pH/thermo-responsive chitosan­g­N­isopropylacrylamide (Chi-g-NIPAAm) polymer matrix. The as-prepared MagSi@Chi-g-NIPAAm particles exhibit superparamagnetic behavior with a saturation magnetization (Ms) of 20.14 emu/g. In addition, the MagSi@Chi-g-NIPAAm particles can act as a heat source when subject to an alternating magnetic field (AMF) and have a specific absorptions rate (SAR) of 8.36 Wg-1. The release of the drug DOX from the synthesized particles is sensitive to both the pH and temperature of its environment. We have compared the drug release when the solution is externally heated up and when it is heated up by the AMF (internal heating). For external heating (when the pH/temperature is 4.0/45 °C), 83.30 ±â€¯2.92% of the DOX were released within the first 5 h. The release of the DOX by the particles in pH 7.4 (temperature of 37 °C) was much slower (around 25.87 ±â€¯1.30% after 25 h). The release of the DOX was much higher (under an acidic condition pH = 4.0) around 57.13 ±â€¯2.36% within 1 h in the presence of AMF heating. The in vitro cytotoxicity tests of the of DOX-loaded MagSi@Chi-g-NIPAAm particles towards HeLa cancer cells. In general, the toxicities of the drug DOX as part of a MagSi@Chi-g-NIPAAm particles were less than those of the standalone DOX until the concentration of DOX-loaded particles reached 250 µg/mL, after which the toxicity of DOX in both forms were the same.

Fabrication of biocomposite scaffolds made with modified hydroxyapatite inclusion of chitosan-grafted-poly(methyl methacrylate) for bone tissue engineering.

In the present study, composite scaffolds of chitosan-graft-poly(methyl methacrylate) (Chi-g-PMMA) and mineral ions-loaded hydroxyapatite (mHA) (obtained by the hydrothermal treatment of hydroxyapatite (HA) in a simulated body fluid (SBF) solution (mHA@Chi-g-PMMA)) were prepared by the blending method. The physical properties, bioactivity, biological properties and their capabilities for sustained drug and protein release were studied. Physicochemical analysis showed a successful incorporation of the mineral ions in the HA particles and a good distribution of the mHA within the Chi-g-PMMA polymer matrix. The compressive strength and the Young's modulus were 15.760 ± 0.718 and 658.452 ± 17.020 MPa, respectively. In bioactivity studies, more apatite formation on the surface were seen after immersion in the SBF solution. In vitro growth experiments using UMR-106 osteoblast-like cells on the mHA@Chi-g-PMMA scaffold case showed that the attachment, viability and proliferation of the cells on the scaffolds had improved after 7 d of immersion. The in vitro release of two compounds (the cancer drug, doxorubicin (DOX)) and bovine serum albumin (BSA)), which had been attached to separate mHA@Chi-g-PMMA scaffolds, were studied to determine their suitability as drug delivery vehicles. It was found that the sustained release of DOX was 73.95% and of BSA was 57.27% after 25 h of incubation. These experimental results demonstrated that the mHA@Chi-g-PMMA composite can be utilized as a scaffold for bone cells ingrowth and also be used for drug delivery during the bone repairing.

SIR Model for Dengue Disease with Effect of Dengue Vaccination.

The dengue disease is caused by dengue virus, and there is no specific treatment. The medical care by experienced physicians and nurses will save life and will lower the mortality rate. A dengue vaccine to control the disease is available in Thailand since late 2016. A mathematical model would be an important way to analyze the effects of the vaccination on the transmission of the disease. We have formulated an SIR (susceptible-infected-recovered) model of the transmission of the disease which includes the effect of vaccination and used standard dynamical modelling methods to analyze the effects. The equilibrium states and their stabilities are investigated. The trajectories of the numerical solutions plotted into the 2D planes and 3D spaces are presented. The main contribution is determining the role of dengue vaccination in the model. From the analysis, we find that there is a significant reduction in the total hospitalization time needed to treat the illness.

Effect of lipid peroxidation on the properties of lipid bilayers: a molecular dynamics study.

Lipid peroxidation plays an important role in cell membrane damage. We investigated the effect of lipid peroxidation on the properties of 1-palmitoyl-2-linoleoyl-sn-glycero-3-phosphatidylcholine (PLPC) lipid bilayers using molecular dynamics simulations. We focused on four main oxidation products of linoleic acid with either a hydroperoxide or an aldehyde group: 9-trans, cis-hydroperoxide linoleic acid, 13-trans, cis-hydroperoxide linoleic acid, 9-oxo-nonanoic acid, and 12-oxo-9-dodecenoic acid. These oxidized chains replaced the sn-2 linoleate chain. The properties of PLPC lipid bilayers were characterized as a function of the concentration of oxidized lipids, with concentrations from 2.8% to 50% for each oxidation product. The introduction of oxidized functional groups in the lipid tail leads to an important conformational change in the lipids: the oxidized tails bend toward the water phase and the oxygen atoms form hydrogen bonds with water and the polar lipid headgroup. This conformational change leads to an increase in the average area per lipid and, correspondingly, to a decrease of the bilayer thickness and the deuterium order parameters for the lipid tails, especially evident at high concentrations of oxidized lipid. Water defects are observed in the bilayers more frequently as the concentration of the oxidized lipids is increased. The changes in the structural properties of the bilayer and the water permeability are associated with the tendency of the oxidized lipid tails to bend toward the water interface. Our results suggest that one mechanism of cell membrane damage is the increase in membrane permeability due to the presence of oxidized lipids.

The stochastic model of non-equilibrium mutagen-induced alterations of DNA: implication to genetic instability in cancer.

Genetic alterations such as point mutations, chromosomal rearrangements, modification of DNA methylation and chromosome aberrations accumulate during the lifetime of an organism. They can be caused by intrinsic errors in the DNA replication and repair as well as by external factors such as exposure to mutagenic substances or radiation. The main purpose of the present work is to begin an exploration of the stochastic nature of non-equilibrium DNA alteration caused by events such as tautomeric shifts. This is done by modeling the genetic DNA code chain as a sequence of DNA-bit values ('1' for normal bases and '-1' for abnormal bases). We observe the number of DNA-bit changes resulting from the random point mutation process which, in the model, is being induced by a stochastic Brownian mutagen (BM) as it diffuses through the DNA-bit systems. Using both an analytical and Monte Carlo (MC) simulation techniques, we observe the local and global number of DNA-bit changes. It is found that in 1D, the local DNA-bit density behaves like 1/t, the global total number of the switched (abnormal) DNA-bit increases as t. The probability distribution P(b, 0, t) of b(0, t) is log-normal. It is also found that when the number of mutagens is increased, the number of the total abnormal DNA-bits does not grow linearly with the number of mutagens. All analytic results are in good agreement with the simulation results.

Effect of Rainfall for the Dynamical Transmission Model of the Dengue Disease in Thailand.

The SEIR (Susceptible-Exposed-Infected-Recovered) model is used to describe the transmission of dengue virus. The main contribution is determining the role of the rainfall in Thailand in the model. The transmission of dengue disease is assumed to depend on the nature of the rainfall in Thailand. We analyze the dynamic transmission of dengue disease. The stability of the solution of the model is analyzed. It is investigated by using the Routh-Hurwitz criteria. We find two equilibrium states: a disease-free state and an endemic equilibrium state. The basic reproductive number (R0) is obtained, which indicates the stability of each equilibrium state. Numerical results taking into account the rainfall are obtained and they are seen to correspond to the analytical results.

The Study of Metal Sulfide as Efficient Counter Electrodes on the Performances of CdS/CdSe/ZnS-co-sensitized Hierarchical TiO2 Sphere Quantum Dot Solar Cells.

The effects of using different counter electrode metal sulfides on the performances of solar cells made with CdS/CdSe/ZnS quantum dots co-sensitized onto hierarchical TiO2 spheres (HTSs) used as photo-electrode are reported. The HTS in the QDSSCs is composed of an assembly of numerous TiO2 spheres made by the solvolthermal method. The photoelectrical performance of HTS/CdS/CdSe/ZnS coupled to CuS or to Cu2ZnSn(S1 - x Se x )4 with x = 0, 0.5, or 1.0 counter electrodes (CEs) were compared to those coupled to Pt CE. The HTS/CdS/CdSe/ZnS coupled to the CuS CE showed the highest power conversion efficiency η (of 3.46%). The efficiencies η of 1.88, 2.64, and 2.06% were obtained for CZTS (x = 0), CZTS0.5Se0.5 (x = 0.5), and CZTSe (x = 1), respectively. These are significantly higher than those using a standard Pt CE (η = 0.37%). These higher efficiencies are the results of the higher electrocatalytic activities when the metal sulfide CEs are used.

Physico-chemical and in vitro cellular properties of different calcium phosphate-bioactive glass composite chitosan-collagen (CaP@ChiCol) for bone scaffolds.

In the present study, scaffolds for bone tissue engineering applications were made by immersing the inorganic phases of three different calcium phosphate (CaPs) (hydroxyapatite (HA), tricalcium phosphate (TCP), and biphasic calcium phosphate (BCP)) mixing bioactive glass (15Ca:80Si:5P) (BG) with polycaprolactone (PCL) as a binder in an organic phase of chitosan/collagen (ChiCol) matrix (CaPBG@ChiCol). Porous scaffolds were obtained by freeze drying the combinations. The mechanical properties and in vitro growth of rat osteoblast-like UMR-106 cells were investigated. The investigation indicated that the compressive strength was controlled by the types of CaP. The highest compressive modulus of the composites was 479.77 MPa (23.84 MPa for compressive strength) which is for the BCPBG@ChiCol composite. Compressive modulus of 459.01 and 435.95 MPa with compressive strength of 22.73 and 17.89 MPa were observed for the HABG@ChiCol and TCPBG@ChiCol composites, respectively. In vitro cell availability and proliferation tests confirmed the osteoblast attachment and growth on the CaPBG@ChiCol surface. Comparing the scaffolds, cells grown on the BCPBG based composite showed the higher cell density. To test its bioactivity, BCPBG@ChiCol was chosen for MTT and ALP assays on UMR-106 cells. The results indicated that the UMR-106 cells were viable and had higher ALP activity as the culturing times were increased. Therefore, ChiCol-fabricated BCPBG scaffold shows promise for bone regeneration. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1758-1766, 2017.

Evaluation of bioactive glass incorporated poly(caprolactone)-poly(vinyl alcohol) matrix and the effect of BMP-2 modification.

Composite materials having mechanical and biological properties similar to those of human bones are needed for bone regeneration and repair. In the present study, composites were made by incorporating bioactive glass (BG) into polycaprolactone (PCL)-polyvinyl alcohol (PVA) (PCLPVA) matrix. Composites with different BG contents of 10, 25 and 50wt% were fabricated by an in-situ blending method. Physicochemical properties measurements found that the composite with 50wt% BG in the PCLPVA organic matrix exhibited the best mechanical properties (compressive strength and compressive young's modulus up to 32.26MPa and 530.91MPa, respectively). We investigated the effects of the BG content on cell adhesion, proliferation and osteogenic activity of UMR-106 cells grown on the scaffolds using in vitro cell culture assay. The composite scaffolds having 25wt% BG showed a significant increase in their cell adhesion capability and a faster cell proliferation. They also exhibited cell adhesion and spreading morphology after only 5days of culturing. For these reasons, we chose to attach the bone morphogenetic protein (BMP)-2 to this composite. The resulting composite (labeled BMP-2-loaded PCLPVABG25) showed significant improvement in the UMR-106 cells adhesion, in the enhancement in osteogenic differentiation and osteoinductivity of this composite.

Synthesis of doxorubicin-PLGA loaded chitosan stabilized (Mn, Zn)Fe2O4 nanoparticles: Biological activity and pH-responsive drug release.

We have synthesized Mn1-xZnxFe2O4 ((Mn, Zn) ferrite) magnetic nanoparticles (MNPs) having radius of 25nm to act as platforms for delivering drugs. The Mn0.9Zn0.1Fe2O4 MNPs exhibit superparamagnetic behavior with large saturation magnetization (MS). They were encapsulated in polymer so that they can be developed into PLGA-coated chitosan stabilized (Mn, Zn) MNPs, i.e., DOX-PLGA@CS@Mn0.9Zn0.1Fe2O4 which can serve as an effective carrier of the anti-cancer drug doxorubicin (DOX) whose release would be controlled by the pH in the environment surrounding the cancer tumor. The structure of the as-prepared particles is of a magnetic core-encapsulated by polymer shell layer of around 50nm thick. At a pH of 4.0, the DOX release within the first 5h is fast (around 57%). It becomes slower (around 46% over the next 25h) when the pH is increased to 7.4. The DOX-PLGA@CS@Mn0.9Zn0.1Fe2O4 (for concentrations lower than 125µgmL(-1)) shows lower toxicity against HeLa cells using DOX only. When the DOX-PLGA@CS@Mn0.9Zn0.1Fe2O4 is increased to 250µgmL(-1), the DOX-PLGA@CS@Mn0.9Zn0.1Fe2O4 shows greater anti-cancer activity and has satisfactory therapeutic effect. The slow sustained release of the DOX by the drug loaded particles when they are in the physiological pH environment (7.4) of normal tissues and mild toxicity of DOX against cancer cell at low concentration point to the DOX loaded PLGA@CS@Mn0.9Zn0.1Fe2O4 being safely used for treating cancer. The higher dosage of DOX needed to kill the cancer cells will be released when the synthesized carriers are subject to the pH stimuli surrounding these cells.