Keratin protein nanofibers from merino wool yarn: a top-down approach for the disintegration of hierarchical wool architecture to extract α-keratin protein nanofibers.

We report the extraction of keratin nanofibers from the medulla of a parent yarn after denaturing the cuticle and cortex microstructures of a merino wool yarn. Controlled alkaline hydrolysis, followed by high-speed blending in acetic acid, allowed for the extraction of keratin protein nanofibers with an average diameter of 25 nm and a length of less than 3 µm. SEM and AFM analyses showed the removal of cuticle cells from the yarn. FT-IR and DSC analyses confirmed the hydrolysis and denaturation of the sheet protein matrix of cuticle cells. XPS analysis provided strong evidence for the gradual removal of the epicuticle, cuticle cells, and cortex of the hierarchical wool structure with an increase in alkaline hydrolysis conditions. It was confirmed that the merino wool yarn subjected to hydrolysis under alkaline conditions exposed its internal fibrillar surface. In an acetic acid medium, these fibrillar surfaces obtained a surface charge, which further supported the defibrillation of the structure into its individual nanofibrils during high-speed blending. The extracted nanostructures constitute mainly α-helical proteins. The morphology of the nanofibers is composed of a uniform circular cross-section based on the images obtained using AFM, TEM, and SEM. The extracted nanofibers were successfully fabricated into transparent sheets that can be used in several applications.

Ilmenite-derived titanic acid species: exploring their outstanding light-independent antibacterial activity.

The emergence of resistance in detrimental pathogenic bacteria towards well-recognized antibiotics has greatly impacted global medicine, consequently exploring potent antibacterial compounds is becoming a potential area of research. Although photocatalytic metal oxides have been extensively explored in this regard, their applicability is diminished due to the requirement of photon energy. Therefore, in our study, we explored the light-independent antibacterial effect of two unexplored titanium species, known as metatitanic acid (MTA) and potassium titanate, against Staphylococcus aureus, Escherichia coli, and Pseudomonas spp. using the disk diffusion method in Luria-Bertani agar medium, where the well-known antibiotic, gentamicin, was used as the positive control. These two titanium compounds were readily synthesized through a novel process which was originally developed for the extraction of TiO2 from ilmenite. The synthesized MTA was characterized using FT-IR, Raman spectroscopy, XRD, TGA, UV-visible spectroscopy, and SEM. According to our findings, both MTA and potassium titanate exhibited superior light-independent antibacterial properties, where for some concentrations, the effect was even greater than gentamicin. However, nano-TiO2 totally failed as an antibacterial compound against the tested three strains under dark conditions.

The blending effect of natural polysaccharides with nano-zirconia towards the removal of fluoride and arsenate from water.

Nano-zirconia (ZO) was synthesized using a microwave-assisted one-pot precipitation route. Two biopolymers, chitosan (CTS) and carboxymethyl cellulose were blended with ZO at different w/w ratios. The formulation with 30% w/w chitosan (ZO-CTS) was found to give enhanced uptake of F- and As(V). ZO and the most effective ZO-CTS system were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. These confirmed the formation of a composite system containing nanoparticles of 50 nm in size, in which ZO was present in the amorphous form. It was observed that the combination of ZO with CTS improved the F- and As(V) adsorption capacity most notably at pH 5.5. Fluoride adsorption by ZO-CTS followed the Freundlich isotherm model, with an adsorption capacity of 120 mg g-1. Adsorption of As(V) by ZO-CTS could be fitted with both the Langmuir and Freundlich isotherm models and was found to have a capacity of 14.8 mg g-1. Gravity filtration studies conducted for groundwater levels indicated the effectiveness of ZO-CTS in adsorbing As(V) and F- at a pH of 5.5. The ability of the ZO-CTS in removing Cd(II) and Pb(II) was also investigated, and no such enhancement was observed, and found the neat ZO was the most potent sorbent here.

Enhancement of Release and Solubility of Curcumin from Electrospun PEO-EC-PVP Tripolymer-Based Nanofibers: A Study on the Effect of Hydrogenated Castor Oil.

This study reveals the state-of-the-art fabrication of a tripolymer-based electrospun nanofiber (NF) system to enhance the release, solubility, and transdermal penetration of curcumin (Cur) with the aid of in situ release of infused castor oil (Co). In this regard, Cur-loaded Co-infused polyethylene oxide (PEO), ethyl cellulose (EC), and polyvinyl pyrrolidone (PVP) tripolymer-based NF systems were developed to produce a hybridized transdermal skin patch. Weight percentages of 1-4% Cur and 3-10% of Co were blended with PEO-EC-PEO and PEO-EC-PVP polymer systems. The prepared NFs were characterized by SEM, TEM, FT-IR analysis, PXRD, differential scanning calorimetry (DSC), and XPS. Dialysis membranes and vertical Franz diffusion cells were used to study the in vitro drug release and transdermal penetration, respectively. The results indicated that maintaining a Cur concentration of 1-3 wt % with 3 wt % Co in both PEO-EC-Co-Cur@PEO and PEO-EC-Co-Cur@PVP gave rise to nanofibers with lowered diameters (144.83 ± 48.05-209.26 ± 41.80 nm and 190.20 ± 59.42-404.59 ± 45.31 nm). Lowered crystallinity observed from the PXRD patterns and the disappearance of exothermic peaks corresponding to the melting point of Cur suggested the formation of an amorphous NF structure. Furthermore, the XPS data revealed that the Cur loading will possibly take place at the inner interface of PEO-EC-Co-PEO and PEO-EC-Co-PVP NFs rather than on the surface. The beneficiary role of Co on the release and dermal penetration of Cur was further confirmed from the respective release data which indicated that PEO-EC-Co-Cur@PEO would lead to a rapid release (4-5 h), while PEO-EC-Co-Cur@PVP would lead to a sustained release over a period of 24 h in the presence of Co. Transdermal penetration of the released Cur was further evidenced with the development of color in the receiver compartment of the diffusion cell. DPPH results further corroborated that a sustained antioxidant activity is observed in the released Cur where the free-radical scavenging activity is intact even after subjecting to an electrospinning process and under extreme freeze-thaw conditions.

Nanomagnetite- and Nanotitania-Incorporated Polyacrylonitrile Nanofibers for Simultaneous Cd(II)- and As(V)-Ion Removal Applications.

This work reports the fabrication of nanomagnetite- and nanotitania-incorporated polyacrylonitrile nanofibers (MTPANs) by an electrospinning process, which has the potential to be used as a membrane material for the selective removal of Cd(II) and As(V) in water. The fiber morphology was characterized by scanning electron microscopy (SEM). The incorporation of nanomagnetite and nanotitania in the composite fiber matrix was confirmed by energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy. The fibers doped with nanomagnetite and nanotitania (MPAN and TPAN fibers, respectively), as well as MTPAN and neat polycrylonitrile (PAN) fibers, after thermally stabilizing at 275 °C in air, were assessed for their comparative As(V)- and Cd(II)-ion removal capacities. The isotherm studies indicated that the highest adsorption of Cd(II) was shown by MTPAN, following the Langmuir model with a q m of 51.5 mg/m2. On the other hand, MPAN showed the highest As(V)adsorption capacity, following the Freundlich model with a K F of 0.49. The mechanism of adsorption of both Cd(II) and As(V) by fibers was found to be electrostatically driven, which was confirmed by correlating the point of zero charges (PZC) exhibited by fibers with the pH of maximum ion adsorptions. The As(V) adsorption on MPAN occurs by an inner-sphere mechanism, whereas Cd(II) adsorption on MTPAN is via both surface complexation and an As(V)-assisted inner-sphere mechanism. Even though the presence of coexistent cations, Ca(II) and Mg(II), has been shown to affect the Cd(II) removal by MTPAN, the MTPAN structure shows >50% removal efficiency even for minute concentrations (0.5 ppm) of Cd(II) in the presence of high common ion concentrations (10 ppm). Therefore, the novel polyacrylonitrile-based nanofiber material has the potential to be used in polymeric filter materials used in water purification to remove As(V) and Cd(II) simultaneously.

Structure-Activity Relationship of Lanthanide-Incorporated Nano-Hydroxyapatite for the Adsorption of Fluoride and Lead.

The growing demand for water purification provided the initial momentum to produce lanthanide-incorporated nano-hydroxyapatite (HAP) such as HAP·CeO2, HAP·CeO2·La(OH)3 (2:1), and HAP·CeO2·La(OH)3 (3:2). These materials open avenues to remove fluoride and lead ions from contaminated water bodies effectively. Composites of HAP containing CeO2 and La(OH)3 were prepared using in situ wet precipitation of HAP, followed by the addition of Ce(SO4)2 and La(NO3)3 into the same reaction mixture. The resultant solids were tested for the removal of fluoride and lead ions from contaminated water. It was found that the composite HAP·CeO2 shows fluoride and lead ion removal capacities of 185 and 416 mg/g, respectively. The fluoride removal capacity of the composite was improved when La(OH)3 was incorporated and it was observed that the composite HAP·CeO2·La(OH)3 (3:2) has the highest recorded fluoride removal capacity of 625 mg/g. The materials were characterized using scanning electron microscopy-energy-dispersive X-ray (SEM-EDX) spectrometry, Fourier transform infrared (FT-IR) spectrometry, X-ray powder diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET) surface area analysis. Analysis of results showed that Ce and La are incorporated in the HAP matrix. Results of kinetic and leaching analyses indicated a chemisorptive behavior during fluoride and lead ion adsorption by the composites; meanwhile, the thermodynamic profile shows a high degree of feasibility for fluoride and lead adsorption.

Biopolymer-Based Nanohydroxyapatite Composites for the Removal of Fluoride, Lead, Cadmium, and Arsenic from Water.

In this study, hydroxyapatite (HAP) nanocomposites were prepared with chitosan (HAP-CTS), carboxymethyl cellulose (HAP-CMC), alginate (HAP-ALG), and gelatin (HAP-GEL) using a simple wet chemical in situ precipitation method. The synthesized materials were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, Brunauer-Emmett-Teller surface area analysis, and thermogravimetric analysis. This revealed the successful synthesis of composites with varied morphologies. The adsorption abilities of the materials toward Pb(II), Cd(II), F-, and As(V) were explored, and HAP-CTS was found to have versatile adsorption properties for all of the ions, across a wide range of concentrations and pH values, and in the presence of common ions found in groundwater. Additionally, X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy confirmed the affinity of HAP-CTS toward multi-ion mixture containing all four ions. HAP-CTS was hence engineered into a more user-friendly form, which can be used to form filters through its combination with cotton and granular activated carbon. A gravity filtration study indicates that the powder form of HAP-CTS is the best sorbent, with the highest breakthrough capacity of 3000, 3000, 2600, and 2000 mL/g for Pb(II), Cd(II), As(V), and F-, respectively. Hence, we propose that HAP-CTS could be a versatile sorbent material for use in water purification.

Nano-manganese oxide and reduced graphene oxide-incorporated polyacrylonitrile fiber mats as an electrode material for capacitive deionization (CDI) technology.

Capacitive deionization (CDI) is a trending water desalination method during which the impurity ions in water can be removed by electrosorption. In this study, nano-manganese dioxide (MnO2) and reduced graphene oxide (rGO)-doped polyacrylonitrile (PAN) composite fibers are fabricated using an electrospinning technique. The incorporation of both MnO2 and rGO nanomaterials in the synthesized fibers was confirmed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). The electrochemical characteristics of electrode materials were examined using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and constant current charge-discharge cycles (CCCDs). The specific capacitance of the PAN electrode increased with increasing MnO2 and rGO contents as well as when thermally treated at 280 °C. Thermally treated composite fibers with 17% (w/w) MnO2 and 1% (w/w) rGO (C-rGOMnPAN) were observed to have the best electrochemical performance, with a specific capacitance of 244 F g-1 at a 10 mV s-1 scan rate. The electrode system was used to study the removal of sodium chloride (NaCl), cadmium (Cd2+) and lead (Pb2+) ions. Results indicated that NaCl showed the highest electrosorption (20 472 C g-1) compared to two heavy metal salts (14 260 C g-1 for Pb2+ and 6265 C g-1 for Cd2+), which is most likely to be due to the ease of mass transfer of lighter Na+ and Cl- ions; When compared, Pb2+ ions tend to show more electrosorption on these fibers than Cd2+ ions. Also, the C-rGOMnPAN electrode system is shown to work with 95% regeneration efficiency when 100 ppm NaCl is used as the electrolyte. Hence, it is clear that the novel binder-free, electrospun C-rGOMnPAN electrodes have the potential to be used in salt removal and also for the heavy metal removal applications of water purification.

A magnetically retrievable air and moisture stable gold and palladium nanocatalyst for efficient C-C coupling reactions.

In this study, we report the synthesis of a highly stable, magnetically retrievable gold and palladium nanocatalyst (AuPd@AMNPs), highly active in Suzuki cross-coupling and related homocoupling reactions. The active catalytic component in this system is palladium, which can only be stabilized in the presence of gold nanoparticles. There is no significant loss of activity even after prolonged storage exposed air and moisture. The versatile nature AuPd@AMNPs is demonstrated through the selective catalysis of the homocoupling of phenylboronic acid under low concentrations of O2 and the oxidation of phenylboronic acid to phenol under high O2 concentrations. AuPd@AMNPs also demonstrated Ullmann-type homocoupling of 4-iodotolene with excellent yields. The magnetically retrieved catalyst could be re-used up to six times in Suzuki-Miyaura cross-coupling with consistently high activity and with a minimal loss of the noble metal species. Through these reactions we show that the gold-stabilized AuPd@AMNPs can be used as stable and recyclable palladium reservoir for multiple palladium-catalysed reactions.

Nanofibrous cosmetic face mask for transdermal delivery of nano gold: synthesis, characterization, release and zebra fish employed toxicity studies.

This study involves the generation of gold nanoparticles (Au NPs) via a novel natural/non-toxic methodology using tea and orange-peel extracts. These were then embedded into a novel blend composed of a polyethylene oxide and gelatin (PEO-Gel) fibre mat. The scanning electron microscopy results indicated that the addition of both collagen (COL) and ascorbic acid (AA) into the PEO-Gel system (PEO-Gel-AA-COL system) enhances the Au NP incorporation into nanofibres leading to a diameter of 164.60 ± 20.95 and 192.43 ± 39.14 nm in contrast to the spraying observed with the Au PEO-Gel system alone. Releasing studies conducted over 30 min indicated that the PEO-Gel-AA-COL-orange peel Au (OpAu) system accounts for a higher content of Au release than the green tea Au (GtAu) NP system where a maximum release could be attained within 10-30 min depending on the amount of Au NPs that have been incorporated. Moreover, the transdermal diffusion studies conducted using Strat membrane indicated that Au NPs from both formulations (PEO-Gel-AA-COL-GtAu nanofibre, PEO-Gel-AA-COL-OpAu nanofibre) have diffused through the stratum corneum and trapped in the dermis and epidermis indicating its transdermal deliverability. Additionally, 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay revealed that nanofibres have similar radical scavenging activity like AA standard. Toxicity evaluation on a zebra fish embryo model confirmed that both GtAu NPs and OpAu NPs do not induce any teratogenic activity and are safe to be used in the range of 1.0-167 µg ml-1.

Shape-stabilization of polyethylene glycol phase change materials with chitin nanofibers for applications in "smart" windows.

Polyethylene glycol (PEG) based shape-stabilized phase change materials (PCMs) were successfully prepared using chitin nanofibers (CNFs). CNFs were isolated from crab shells and, resulted CNFs were several tenth of nanometers in diameter and had lengths ranging from several hundreds of nanometers to few micrometers. Introduction of CNFs in to PEG resulted shape-stabilized composites. Various PEG-CNF composites were fabricated and the resulted materials were encapsulated in to an optical device to obtain temperature dependent transparency. In the optimized formulation, the device remained opaque (∼3.5 %) below the melting point of the PEG-CNF composite and became gradually transparent as the temperature of the device increased ultimately stabilizing at a transmittance value of ∼88 %. CNF phase was seen to have an effect on the thermal properties of the PEG-CNF material. The work introduces a novel strategy for the shape stabilization of liquid-solid phase change materials unlocking potential for new PCM based devices.

Colloidal stability of chitin nanofibers in aqueous systems: Effect of pH, ionic strength, temperature & concentration.

Chitin nanofibers are emerging as a very attractive bio-compatible material in number of advanced materials applications. In this work, the colloidal stability of the chitin nanofibers was investigated against pH, ionic strength, temperature and concentration. Aqueous solutions of chitin nanofibers were found to be stabilized due to the carboxylic acid moieties available in the fibril surface as evidenced by both 13C NMR and potentiometric titration methods. Amongst others, pH and ionic strength were the most influential factors which determine both hydrodynamic diameter and zeta potential. The chitin nanofiber dispersions were stabilized at pH values higher than 7, with an average zeta potential value of -22.5 mV. A monotonic increase of zeta potential was observed with respect to increase in ionic strength. Zeta potential got stabilized at -14.0 mV for ionic strengths over 20 mM of NaCl. Hydrodynamic particle size was also found to be a function of temperature and concentration.

Titanium carbide ceramic nanocrystals to enhance the physicochemical properties of natural rubber composites.

The mechanical strength of natural rubber (NR) was enhanced by incorporating novel titanium carbide (TiC) nanocrystals as a filling material. The rubber nanocomposites were prepared through mixing TiC nanoparticles with NR latex and the resulting NR/TiC masterbatch was further mixed at the solid stage with other chemicals via internal mixing. The final rubber composites prepared using TiC as the nanofiller were denoted as NR/TiC-0, NR/TiC-0.5, NR/TiC-1.0, NR/TiC-2.5, and NR/TiC-5.0; moreover, a comparative study was conducted using carbon black (CB-330) as the filler and the composites were denoted as NR/CB-1.0 and NR/CB-5.0. As per the results of tensile tests, the NR/TiC-1.0 composite revealed the highest tensile value of 31.13 MPa and this indicated improvement by 92% compared to that of the control (NR/TiC-0 (16.22 MPa)); moreover, it indicated improvements by 73% and 63% compared to the values of NR/CB-1.0 and NR/CB-5.0, respectively. Moreover, scanning electron microscopy (SEM) analysis revealed a better dispersion of the NR/TiC-1.0 composite compared to the other composites. Furthermore, dynamic mechanical analysis (DMA) was conducted to observe the energy storage and loss properties at dynamic conditions; the results revealed that the highest storage peak and lowest loss peak were observed for the NR/TiC-1.0 composite. Also, thermogravimetric analysis revealed the superior thermal stability of the NR/TiC-1.0 composite to that of the others at the NR degradation temperature of around 400 °C. Importantly, the curing time (t 90) of NR/TiC-1.0 was reduced considerably compared to that of the other composites even the NR/CB composites, which would be beneficial for industries to save energy at the curing stages of tire-like applications. The improvements were significant when compared to the industrially well-known NR/CB composites and well above the industrially required minimum parameters of the tire industry. Ultimately, this will open up a distinct avenue for natural rubber reinforcement.

Recent developments in the use of organic-inorganic nanohybrids for drug delivery.

Organic-inorganic nanohybrid (OINH) structures providing a versatile platform for drug delivery with improved characteristics are an area which has gained recent attention. Much effort has been taken to develop these structures to provide a viable treatment options for much alarming diseases such as cancer, bone destruction, neurological disorders, and so on. This review focuses on current work carried out in producing different types of hybrid drug carriers identifying their properties, fabrication techniques, and areas where they have been applied. A brief introduction on understating the requirement for blending organic-inorganic components into a nanohybrid drug carrier is followed with an elaboration given about the different types of OINHs developed currently highlighting their properties and applications. Then, different fabrication techniques are discussed given attention to surface functionalization, one-pot synthesis, wrapping, and electrospinning methods. Finally, it is concluded by briefing the challenges that are remaining to be addressed to obtain multipurpose nanohybrid drug carriers with wider applicability. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies.

The effect of collection substrate on electrospun ciprofloxacin-loaded poly(vinylpyrrolidone) and ethyl cellulose nanofibers as potential wound dressing materials.

In this work, nanofibers based on hydrophilic poly(vinylpyrrolidone) (PVP) and hydrophobic ethyl cellulose (EC) were generated via electrospinning. A model antibiotic, ciprofloxacin (CIF), was also incorporated into the fibers. Fibers were collected on both a foil substrate and a commercial gauze, the latter in the interests of developing a smart fabric. Electron microscopy images revealed that the fibers collected on both foil and fabric were homogeneous and cylindrical. Infrared spectroscopy, X-ray diffraction and differential scanning calorimetry demonstrated that CIF was successfully loaded into the fibers and present in the amorphous physical form. In vitro drug release tests were conducted to simulate drug release from the formulations into a wound site, and as expected the hydrophilic fibers showed much faster release than their hydrophobic analogues. CIF was released through a combined mechanism of polymer erosion and drug diffusion, and the EC nanofibers displayed close to zero-order release over three days. Fibroblast cells are able to grow and proliferate on the fibers. Finally, inhibition zone assays revealed that the growth of both Gram positive and Gram negative bacteria could be effectively inhibited as a result of the presence of CIF in the fibers. There were no marked differences between the fibers collected on foil and on gauze, and electrospinning can be performed directly onto a gauze substrate to prepare a smart fabric.

Effect of networked hybridized nanoparticle reinforcement on the thermal conductivity and mechanical properties of natural rubber composites.

Thermal conductivity of natural rubber (NR) was enhanced by incorporating novel conductive hybrid nanofillers, namely polyaniline grafted carbon black (PANI/CB) nanoparticles and carbon black nanoparticles linked with carbon microfiber (CF/CB) composites. The PANI/CB hybrid fillers were synthesized using an in situ method, where aniline monomers were initially adsorbed onto carbon black spherical domains and, afterwards, it was polymerized in the presence of an oxidizer. Final rubber composites were prepared through melt mixing, where PANI/CB and CF/CB filler loading was kept at 40 parts per hundred of rubber (phr). The thermal conductivity values of the rubber composites with CF/CB (20 : 20) and PANI/CB (20 : 20) yield were 0.45 W m-1 K-1 and 0.31 W m-1 K-1, respectively and the thermal conductivity improved significantly compared to the control (0.25 W m-1 K-1) sample. The higher thermal conductivity values of CF/CB and PANI/CB incorporated composites suggest that the generated networked structure of CF and PANI nanofibers with CB nanoparticles has immensely contributed to enhancing the heat dissipation compared to that of the neat CB rubber composite. Scanning electron micrographs (SEM) confirmed the attachment of the synthesized PANI onto the spherical CB nanoparticles and interconnected morphology of CF/CB and PANI/CB hybrid fillers. The synthesized PANI/CB hybrid filler was further characterized using Fourier-transform infrared (FTIR) spectroscopy to evaluate the chemical properties. Furthermore, thermogravimetric analysis revealed the higher thermal stability of CF/CB (20 : 20) and PANI/CB (20 : 20) composites compared to the control. Moreover, the addition of CF/CB (20 : 20) and PANI/CB (20 : 20) improved the mechanical properties such as ultimate tensile strength, modulus at break, resilience and abrasion resistance significantly and well above the minimum required standard mechanical parameters in the tyre industry. These reinforced composites show great potential to be used as heat dissipating rubber composites in the tyre industry.

Improved nanocomposite of montmorillonite and hydroxyapatite for defluoridation of water.

A novel hydroxyapatite montmorillonite (HAP-MMT) nanocomposite system was synthesized using a simple wet chemical in situ precipitation method. Neat nano hydroxyapatite (HAP) was also synthesized for comparison. The characterization of the materials was carried out using Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) isotherms to study the functional groups, morphology, crystallinity and the surface area respectively. Batch adsorption studies and kinetic studies on fluoride adsorption were conducted for the HAP-MMT system and for neat HAP. The effect of parameters such as contact time, pH, initial concentration, temperature, and thermodynamic parameters and the effect of coexisting ions on fluoride adsorption by HAP-MMT were studied. Results of the isotherm experiments were fitted to four adsorption isotherm models namely Langmuir, Freundlich, Temkin and Dubinin Radushkevich. Fluoride adsorption over HAP-MMT fitted to the Freundlich adsorption isotherm model and showed more than two-fold improved adsorption capacity (16.7 mg g-1) compared to neat HAP. The best-fitting kinetic model for both adsorbents was found to be pseudo second order. Calculated thermodynamic parameters indicated that the fluoride adsorption by HAP-MMT is more favorable compared to that on HAP within the temperature range of 27 °C-60 °C. Improved fluoride adsorption by HAP-MMT is attributed to the exfoliated nature of HAP-MMT. Gravity filtration studies carried out using a 1.5 ppm fluoride solution, which is closer to the ground water fluoride concentrations of Chronic Kidney Disease of unknown etiology (CKDu) affected areas in Sri Lanka, resulted in a 1600 ml g-1 break through volume indicating the potential of HAP-MMT to be used in real applications.

Fabrication of 6-gingerol, doxorubicin and alginate hydroxyapatite into a bio-compatible formulation: enhanced anti-proliferative effect on breast and liver cancer cells.

Ample attention has been devoted to the construction of anti-cancer drug delivery systems with increased stability, and controlled and targeted delivery, minimizing toxic effects. In this study we have designed a magnetically attractive hydroxyapatite (m-HAP) based alginate polymer bound nanocarrier to perform targeted, controlled and pH sensitive drug release of 6-gingerol, doxorubicin, and their combination, preferably at low pH environments (pH 5.3). They have exhibited higher encapsulation efficiency which is in the range of 97.4-98.9% for both 6-gingerol and doxorubicin molecules whereas the co-loading has accounted for a value of 81.87 ± 0.32%. Cell proliferation assays, fluorescence imaging and flow cytometric analysis, demonstrated the remarkable time and dose responsive anti-proliferative effect of drug loaded nanoparticles on MCF-7 cells and HEpG2 cells compared with their neat counter parts. Also, these systems have exhibited significantly reduced toxic effects on non-targeted, non-cancerous cells in contrast to the excellent ability to selectively kill cancerous cells. This study has suggested that this HAP based system is a versatile carrier capable of loading various drug molecules, ultimately producing a profound anti-proliferative effect.

Effective delivery of hydrophobic drugs to breast and liver cancer cells using a hybrid inorganic nanocarrier: A detailed investigation using cytotoxicity assays, fluorescence imaging and flow cytometry.

This study was focused on developing a drug carrier system composed of a polymer containing hydroxyapatite (HAp) shell and a magnetic core of iron oxide nanoparticles. Doxorubicin and/or curcumin were loaded into the carrier via a simple diffusion deposition approach, with encapsulation efficiencies (EE) for curcumin and doxorubicin of 93.03 ±â€¯0.3% and 97.37 ±â€¯0.12% respectively. The co-loading of curcumin and doxorubicin led to a total EE of 76.02 ±â€¯0.48%. Release studies were carried out at pH 7.4 and 5.3, and revealed a greater extent of release at pH 5.3, showing the formulations to have potential applications in tumor microenvironments. Cytotoxicity assays, fluorescence imaging and flow cytometry demonstrated that the formulations could effectively inhibit the growth of MCF-7 (breast) and HEpG2 (liver) cancer cells, being more potent than the free drug molecules both in terms of dose and duration of action. Additionally, hemolysis tests and cytotoxicity evaluations determined the drug-loaded carriers to be non-toxic towards non-cancerous cells. These formulations thus have great potential in the development of new cancer therapeutics.

Heterogeneous in situ polymerization of polyaniline (PANI) nanofibers on cotton textiles: Improved electrical conductivity, electrical switching, and tuning properties.

Electrically conductive cotton fabric was fabricated by in situ one pot oxidative polymerization of aniline. Using a simple heterogeneous polymerization method, polyaniline (PANI) nano fibers with an average fiber diameter of 40-75 nm were grafted in situ onto cotton fabric. The electrical conductivity of the PANI nanofiber grafted fabric was improved 10 fold compared to fabric grafted with PANI nanoclusters having an average cluster size of 145-315 nm. The surface morphology of the cotton fibers was characterized using SEM and AFM. Electrical conductivity of PANI nanofibers on the cotton textile was further improved from 76 kΏ/cm to 1 kΏ/cm by increasing the HCl concentration from 1 M to 3 M in the polymerization medium. PANI grafted cotton fabrics were analyzed using FTIR, and the data showed the presence of polyaniline functional groups on the treated fabric. Further evidence was present for the chemical interaction of PANI with cellulose. Dopant level and morphology dependent electron transition behavior of PANI nanostructures grafted on cotton fabric was further characterized using UV-vis spectroscopy. The electrical conductivity of the PANI nano fiber grafted cotton fabric can be tuned by immersing the fabric in pH 2 and pH 6 solutions for multiple cycles.