Polymer-based nanocomposites have attracted a lot of attention for amperometric biosensor development due to their general physical and chemical properties including biocompatibility, film-forming ability, stability and different functional groups that can be bonded with other biomolecues. In this study, poly-4-vinlyridine homopolymer (P4VP) and polylactic acid-block-poly(2-vinylpyridine) block copolymer (PLA-b-P2VP) were used to hybridize with gold precursors (Au3+) based on the association between the nitrogen of the pyridine group of P4VP or P2VP block with gold precursors. P4VP/Au3+ and PLA-b-P2VP/Au3+ nanocomposites were prepared with ratio of gold to P2VP or P4VP (10:1). The Au3+ in both polymers was reduced to gold nanoparticles (AuNPs) via in-situ approach by using hydrazine. Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-vis), transmission electron microscopy (TEM) and cyclic voltammetry (CV) were used to characterize the structural, morphological and electrochemical properties of the nanocomposites. The peak currents of P4VP/AuNPs and PLA-b-P2VP/AuNPs nanocomposites modified electrode were 6.685 nA and 69.432 nA, respectively, which are much lower than bare electrode (205.019 nA) due to the non-conductivity of P4VP and PLA-b-P2VP. In order to improve the electron transfer capability of electrode, graphene oxide (GO) was blended and electrochemically reduced to obtain P4VP/AuNPs/rGO and PLA-b-P2VP/AuNPs/rGO nanocomposites. After immobilization of these two nanocomposites on electrode through drop casting method, the peak currents of P4VP/AuNPs/rGO and PLA-b-P2VP/AuNPs/rGO nanocomposites modified electrode were 871.172 nA and 663.947 nA, respectively, which are much higher than bare electrode (205.019 nA) and shown good capability to accelerate electron transfer. Based on these characterizations, P4VP/AuNPs/rGO has potential as the nanocomposite to modify the electrode for enzymatic biosensor development.
Incorporation of silver nanomaterial into polymer matrix can further accomplished their potential usage in real life
applications. In our previous study, silver nanoparticles (AgNPs) and silver-graphene oxide nanocomposites (AgGO)
were prepared via a rapid microwave-assisted method. Hereby, the as-synthesized AgNPs or AgGO was dispersed in a
chitosan solution. Subsequently, the resultant mixture solution was further coagulated in a coagulation bath containing
sodium hydroxide via a neutralization process. This resulted in the formation of spherical-shaped chitosan beads.
The structure of the beads showed that the chitosan beads embedded with AgGO exhibited a more porous structure as
compared to the plain chitosan beads. Furthermore, the chitosan beads containing AgNPs or AgGO were tested for
their antibacterial activity against Escherichia coli and Staphylococcus aureus. The antibacterial results indicated that
the silver nanomaterial contained chitosan beads could effectively inhibit the growth of both E. coli and S. aureus as
compared to the bare chitosan beads. The produced chitosan nanocomposite envisioned that can be potentially employed
for water disinfection purpose.
Ayurveda oil contains numerous source of biological constituents which plays an important role in reducing the pain relief caused during bone fracture. The aim of the study is to fabricate the polyurethane (PU) scaffold for bone tissue engineering added with ayurveda amla oil using electrospinning technique. Scanning Electron Microscopy (SEM) analysis showed that the fabricated nanocomposites showed reduced fiber diameter (758 ± 185.46 nm) than the pristine PU (890 ± 116.91 nm). Fourier Infrared Analysis (FTIR) revealed the existence of amla oil in the PU matrix by hydrogen bond formation. The contact angle results revealed the decreased wettability (116° ± 1.528) of the prepared nanocomposites compared to the pure PU (100° ± 0.5774). The incorporation of amla oil into the PU matrix improved the surface roughness. Further, the coagulation assay indicated that the addition of amla oil into PU delayed the blood clotting times and exhibited less toxic to red blood cells. Hence, the fabricated nanocomposites showed enhanced physicochemical and better blood compatibility parameters which may serve as a potential candidate for bone tissue engineering.
The presence of dyes in the aquatic environment as a result of anthropogenic activities, especially textile industries, is a critical environmental challenge that hinders the availability of potable water. Different wastewater treatment approaches have been used to remediate dyes in aquatic environments; however, most of these approaches are limited by factors ranging from high cost to the incomplete removal of the dyes and contaminants. Thus, the use of adsorption as a water treatment technology to remove dyes and other contaminants has been widely investigated using different adsorbents. This study evaluated the significance of chitosan as a viable adsorbent for removing dyes from water treatment. We summarised the literature and research results obtained between 2009 and 2020 regarding the adsorption of dyes onto chitosan and modified chitosan-based adsorbents prepared through physical and chemical processing, including crosslinking impregnation, grafting, and membrane preparation. Furthermore, we demonstrated the effects of various chitosan-based materials and modifications; they all improve the properties of chitosan by promoting the adsorption of dyes. Hence, the application of chitosan-based materials with various modifications should be considered a cutting-edge approach for the remediation of dyes and other contaminants in aquatic environments toward the global aim of making potable water globally available.
The primary challenge in finding a treatment for tuberculosis (TB) is patient non-compliance to treatment due to long treatment duration, high dosing frequency, and adverse effects of anti-TB drugs. This study reports on the development of a nanodelivery system that intercalates the anti-TB drug isoniazid into Mg/Al layered double hydroxides (LDHs). Isoniazid was found to be released in a sustained manner from the novel nanodelivery system in humans in simulated phosphate buffer solutions at pH 4.8 and pH 7.4. The nanodelivery formulation was highly biocompatible compared to free isoniazid against human normal lung and 3T3 mouse fibroblast cells. The formulation was active against Mycobacterium tuberculosis and gram-positive bacteria and gram-negative bacteria. Thus results show significant promise for the further study of these nanocomposites for the treatment of TB.
The treatment of tuberculosis by chemotherapy is complicated due to multiple drug prescriptions, long treatment duration, and adverse side effects. We report here for the first time an in vitro therapeutic effect of nanocomposites based on para-aminosalicylic acid with zinc layered hydroxide (PAS-ZLH) and zinc-aluminum layered double hydroxides (PAS-Zn/Al LDH), against mycobacteria, Gram-positive bacteria, and Gram-negative bacteria. The nanocomposites demonstrated good antimycobacterial activity and were found to be effective in killing Gram-positive and Gram-negative bacteria. A biocompatibility study revealed good biocompatibility of the PAS-ZLH nanocomposites against normal human MRC-5 lung cells. The para-aminosalicylic acid loading was quantified with high-performance liquid chromatography analysis. In summary, the present preliminary in vitro studies are highly encouraging for further in vivo studies of PAS-ZLH and PAS-Zn/Al LDH nanocomposites to treat tuberculosis.
Nystatin is a tetraene diene polyene antibiotic showing a broad spectrum of antifungal activity. In the present study, we prepared a nystatin nanocomposite (Nyst-CS-MNP) by loading nystatin (Nyst) on chitosan (CS) coated magnetic nanoparticles (MNPs). The magnetic nanocomposites were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetry analysis (TGA), vibrating sample magnetometer (VSM), and scanning electron microscopy (SEM). The XRD results showed that the MNPs and nanocomposite are pure magnetite. The FTIR analysis confirmed the binding of CS on the surface of the MNPs and also the loading of Nyst in the nanocomposite. The Nyst drug loading was estimated using UV-Vis instrumentation and showing a 14.9% loading in the nanocomposite. The TEM size image of the MNPs, CS-MNP, and Nyst-CS-MNP was 13, 11, and 8 nm, respectively. The release profile of the Nyst drug from the nanocomposite followed a pseudo-second-order kinetic model. The antimicrobial activity of the as-synthesized Nyst and Nyst-CS-MNP nanocomposite was evaluated using an agar diffusion method and showed enhanced antifungal activity against Candida albicans. In this manner, this study introduces a novel nanocomposite that can decrease fungus activity on-demand for numerous medical applications.
We report the intercalation and characterization of para-amino salicylic acid (PASA) into zinc/aluminum-layered double hydroxides (ZLDHs) by two methods, direct and indirect, to form nanocomposites: PASA nanocomposite prepared by a direct method (PASA-D) and PASA nanocomposite prepared by an indirect method (PASA-I). Powder X-ray diffraction, Fourier-transform infrared spectroscopy, and thermogravimetric analysis revealed that the PASA drugs were accommodated within the ZLDH interlayers. The anions of the drug were accommodated as an alternate monolayer (along the long-axis orientation) between ZLDH interlayers. Drug loading was estimated to be 22.8% and 16.6% for PASA-D and PASA-I, respectively. The in vitro release properties of the drug were investigated in physiological simulated phosphate-buffered saline solution of pH 7.4 and 4.8. The release followed the pseudo-second-order model for both nanocomposites. Cell viability (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide [MTT] assays) was assessed against normal human lung fibroblast MRC-5 and 3T3 mouse fibroblast cells at 24, 48, and 72 hours. The results showed that the nanocomposite formulations did not possess any cytotoxicity, at least up to 72 hours.
A new layered organic-inorganic nanocomposite material with an anti-parkinsonian active compound, L-3-(3,4-dihydroxyphenyl) alanine (levodopa), intercalated into the inorganic interlayers of a Zn/Al-layered double hydroxide (LDH) was synthesized using a direct coprecipitation method. The resulting nanocomposite was composed of the organic moiety, levodopa, sandwiched between Zn/Al-LDH inorganic interlayers. The basal spacing of the resulting nano-composite was 10.9 Å. The estimated loading of levodopa in the nanocomposite was approximately 16% (w/w). A Fourier transform infrared study showed that the absorption bands of the nanocomposite were characteristic of both levodopa and Zn/Al-LDH, which further confirmed intercalation, and that the intercalated organic moiety in the nanocomposite was more thermally stable than free levodopa. The resulting nanocomposite showed sustained-release properties, so can be used in a controlled-release formulation. Cytotoxicity analysis using an MTT assay also showed increased cell viability of 3T3 cells exposed to the newly synthesized nanocomposite compared with those exposed to pure levodopa after 72 hours of exposure.
In the study reported here, magnesium/aluminum (Mg/Al)-layered double hydroxide (LDH) was intercalated with an anticancer drug, protocatechuic acid, using ion-exchange and direct coprecipitation methods, with the resultant products labeled according to the method used to produce them: "PANE" (ie, protocatechuic acid-Mg/Al nanocomposite synthesized using the ion-exchange method) and "PAND" (ie, protocatechuic acid-Mg/Al nanocomposite synthesized using the direct method), respectively. Powder X-ray diffraction and Fourier transform infrared spectroscopy confirmed the intercalation of protocatechuic acid into the inter-galleries of Mg/Al-LDH. The protocatechuic acid between the interlayers of PANE and PAND was found to be a monolayer, with an angle from the z-axis of 8° for PANE and 15° for PAND. Thermogravimetric and differential thermogravimetric analysis results revealed that the thermal stability of protocatechuic acid was markedly enhanced upon intercalation. The loading of protocatechuic acid in PANE and PAND was estimated to be about 24.5% and 27.5% (w/w), respectively. The in vitro release study of protocatechuic acid from PANE and PAND in phosphate-buffered saline at pH 7.4, 5.3, and 4.8 revealed that the nanocomposites had a sustained release property. After 72 hours incubation of PANE and PAND with MCF-7 human breast cancer and HeLa human cervical cancer cell lines, it was found that the nanocomposites had suppressed the growth of these cancer cells, with a half maximal inhibitory concentration of 35.6 μg/mL for PANE and 36.0 μg/mL for PAND for MCF-7 cells, and 19.8 μg/mL for PANE and 30.3 μg/mL for PAND for HeLa cells. No half maximal inhibitory concentration for either nanocomposite was found for 3T3 cells.
Using the chemical reduction method, silver nanoparticles (Ag NPs) were effectively synthesized into the zeolite framework in the absence of any heat treatment. Zeolite, silver nitrate, and sodium borohydride were used as an inorganic solid support, a silver precursor, and a chemical reduction agent, respectively. Silver ions were introduced into the porous zeolite lattice by an ion-exchange path. After the reduction process, Ag NPs formed in the zeolite framework, with a mean diameter of about 2.12-3.11 nm. The most favorable experimental condition for the synthesis of Ag/zeolite nanocomposites (NCs) is described in terms of the initial concentration of AgNO(3). The Ag/zeolite NCs were characterized by ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray fluorescence, and Fourier transform infrared. The results show that Ag NPs form a spherical shape with uniform homogeneity in the particle size. The antibacterial activity of Ag NPs in zeolites was investigated against Gram-negative bacteria (ie, Escherichia coli and Shigella dysentriae) and Gram-positive bacteria (ie, Staphylococcus aureus and methicillin-resistant Staphylococcus aureus) by disk diffusion method using Mueller-Hinton agar at different sizes of Ag NPs. All of the synthesized Ag/zeolite NCs were found to have antibacterial activity. These results show that Ag NPs in the zeolite framework can be useful in different biological research and biomedical applications.
The delivery of a full plasmid, encoding the green fluorescent protein gene into African monkey kidney (Vero3) cells, was successfully achieved using nanobiocomposites based on layered double hydroxides. This demonstrated the potential of using the system as an alternative DNA delivery vector. Intercalation of the circular plasmid DNA, pEGFP-N2, into Mg/Al-NO(3)(-) layered double hydroxides (LDH) was accomplished through anion exchange routes to form the nanobiocomposite material. The host was previously synthesized at the Mg(2+) to Al(3+) molar ratio R(i) = 2 and subsequently intercalated with plasmid DNA. Size expansion of the interlamellae host from 8.8 A in LDH to 42 A was observed in the resulting nanobiocomposite, indicating stable hybridization of the plasmid DNA. The powder x-ray diffraction (PXRD) results, supplemented with Fourier-transform infrared (FTIR) spectroscopy, compositional and electrophoresis studies confirmed the encapsulation episode of the biomaterial. In order to elucidate the use of this resulting nanobiocomposite as a delivery vector, an MTT assay was performed to determine any cytotoxic effects of the host towards cells. The intercalated pEGFP-N2 anion was later successfully recovered through acidification with HNO(3) after treatment with DNA-degrading enzymes, thus also showing the ability of the LDH host to protect the intercalated biomaterial from degradation. Cell transfection studies on Vero3 cells were then performed, where cells transfected with the nanobiocomposite exhibited fluorescence as early as 12 h post-treatment compared to naked delivery of the plasmid itself.
The sol-gel/ultrasonically rout produced the novel MnS2-SiO2 nano-hetero-photocatalysts with the various ratio of MnS2. Prepared nano-catalyst were investigated in the photo-degradation of methylene blue under UV light illumination. Structural and optical attributes of as-prepared nano-catalysts were evaluated by X-ray diffraction and photoelectron spectroscopy. The morphological were studied by scanning electron microscopy-EDS, and dynamic light scattering. The diffuse reflectance spectroscopy was applied to examine the band gap energy. The Eg values of SiO2, MnS2-SiO2-0, MnS2-SiO2-1, and MnS2-SiO2-2 nanocomposites are 6.51, 3.85, 3.17, and 2.67 eV, respectively. The particle size of the SiO2 and MnS2-SiO2-1 nanocomposites were 100.0, and 65.0 nm, respectively. The crystallite size values of MnS2-SiO2-1 were 52.21 nm, and 2.9 eV, respectively. MnS2-SiO2 nano-photocatalyst was recognized as the optimum sample by degrading 96.1% of methylene blue from water. Moreover, the influence of pH of the solution, and contact time as decisive factors on the photo-degradation activity were investigated in this project. The optimum data for pH and time were found 9 and 60 min, respectively. The photo-degradation capacity of MnS2-SiO2-2 is improved (96.1%) due to the low band gap was found from UV-vis DRS. The antimicrobial data of MnS2-SiO2 were studied and demonstrated that the MnS2-SiO2 has fungicidal and bactericidal attributes.
Discovery of a novel anticancer drug delivery agent is important to replace conventional cancer therapies which are often accompanied by undesired side effects. This study demonstrated the synthesis of superparamagnetic magnetite nanocomposites (Fe3O4-NCs) using a green method. Montmorillonite (MMT) was used as matrix support, while Fe3O4 nanoparticles (NPs) and carrageenan (CR) were used as filler and stabilizer, respectively. The combination of these materials resulted in a novel nanocomposite (MMT/CR/Fe3O4-NCs). A series of characterization experiments was conducted. The purity of MMT/CR/Fe3O4-NCs was confirmed by X-ray diffraction (XRD) analysis. High resolution transmission electron microscopy (HRTEM) analysis revealed the uniform and spherical shape of Fe3O4 NPs with an average particle size of 9.3 ± 1.2 nm. Vibrating sample magnetometer (VSM) analysis showed an Ms value of 2.16 emu/g with negligible coercivity which confirmed the superparamagnetic properties. Protocatechuic acid (PCA) was loaded onto the MMT/CR/Fe3O4-NCs and a drug release study showed that 15% and 92% of PCA was released at pH 7.4 and 4.8, respectively. Cytotoxicity assays showed that both MMT/CR/Fe3O4-NCs and MMT/CR/Fe3O4-PCA effectively killed HCT116 which is a colorectal cancer cell line. Dose-dependent inhibition was seen and the killing was enhanced two-fold by the PCA-loaded NCs (IC50-0.734 mg/mL) compared to the unloaded NCs (IC50-1.5 mg/mL). This study highlights the potential use of MMT/CR/Fe3O4-NCs as a biologically active pH-responsive drug delivery agent. Further investigations are warranted to delineate the mechanism of cell entry and cancer cell killing as well as to improve the therapeutic potential of MMT/CR/Fe3O4-NCs.
The development of nanocomposites has swiftly changed the horizon of drug delivery systems in defining a new platform. Major understanding of the interaction of nanocomposites with cells and how the interaction influences intracellular uptake is an important aspect to study in order to ensure successful utilisation of the nanocomposites. Studies have suggested that the nanocomposites' ability to permeate into biological cells is attributable to their well-defined physicochemical properties with nanoscale size, which is relevant to the nanoscale components of biology and cellular organelles. The functionalized graphene oxide coated with polyethylene glycol, loaded with protocatechuic acid and folic acid (GOP-PCA-FA) nanocomposite intracellular uptake was analysed using transmission electron microscope. The accumulation of fluorescent-labelled nanocomposites in the HepG2 cell was also analysed using a fluorescent microscope. In vitro cellular uptake showed that there was uptake of the drug from 24 h into the cells and the release study using fluorescently tagged nanocomposite demonstrated that release and accumulation were observed at 24 h and 48 h. Moreover, the migration ability of tumor cells is a key step in tumor progression which was observed 48 h after treatment. The GOP serves as a potential nanocarrier system which is capable of improving the therapeutic efficacy of drugs and biomolecules in medical as well as pharmaceutical applications through the enhanced intracellular release and accumulation of the encapsulated drugs. Nonetheless, it is essential to analyse the translocation of our newly developed GOP-PCA-FA, and its efficiency for drug delivery, effective cellular uptake, and abundant intracellular accumulation would be compromised by possible untoward side effects.
Curdlan (CN)-doped montmorillonite/poly(N-isopropylacrylamide-co-N,N'-methylene-bis-acrylamide) [CN/MT/P(NIPA-co-MBA)] smart nanocomposites (NCs) were developed for efficient erlotinib HCl (ERL) delivery to lung cancer cells. The placebo NCs demonstrated excellent biodegradability, pH/thermo-responsive swelling profiles and declined molar mass (M¯c) between the crosslinks with increasing temperature. The XRD, FTIR, DSC, TGA, and SEM analyses revealed the architectural chemistry of these NC scaffolds. The NCs loaded with ERL (F-1-F-3) displayed acceptable diameter (734-1120 nm) and zeta potential (+1.16 to -11.17 mV), outstanding drug entrapping capability (DEE, 78-99%) and sustained biphasic ERL elution patterns (Q8h, 53-91%). The ERL release kinetics of the optimal matrices (F-3) obeyed Higuchi model and their transport occurred through anomalous diffusion. The mucin adsorption behaviour of these matrices followed Freudlich isotherms. As compared to pure ERL, the formulation (F-3) displayed an improved anti-proliferative potential and induced apoptosis more effectively on A549 cells. Thus, the CN-doped smart NCs could be utilized as promising drug-cargoes for lung cancer therapy.
A new graphene-based tetraethoxysilane-methyltrimethoxysilane sol-gel hybrid magnetic nanocomposite (Fe3O4@G-TEOS-MTMOS) was synthesised, characterized and successfully applied in magnetic solid-phase extraction (MSPE) for simultaneous analysis of polar and non-polar organophosphorus pesticides from several water samples. The Fe3O4@G-TEOS-MTMOS nanocomposite was characterized using Fourier transform-infrared spectroscopy, energy-dispersive X-ray spectroscopy, field emission scanning electron microscopy and X-ray diffraction. Separation, determination and quantification were achieved using gas chromatography coupled with micro electron capture detector. Adsorption capacity of the sorbent was calculated using Langmuir equation. MSPE was linear in the range 100-1000 pg mL(-1) for phosphamidon and dimethoate, and 10-100 pg mL(-1) for chlorpyrifos and diazinon, with limit of detection (S/N = 3) of 19.8, 23.7, 1.4 and 2.9 pg mL(-1) for phosphamidon, dimethoate, diazinon and chlorpyrifos, respectively. The LODs obtained is well below the maximum residual level (100 pg mL(-1)) as set by European Union for pesticides in drinking water. Acceptable precision (%RSD) was achieved for intra-day (1.3-8.7%, n = 3) and inter-day (7.6-17.8%, n = 15) analyses. Fe3O4@G-TEOS-MTMOS showed high adsorption capacity (54.4-76.3 mg g(-1)) for the selected OPPs. No pesticide residues were detected in the water samples analysed. Excellent extraction recoveries (83-105%) were obtained for the spiked OPPs from tap, river, lake and sea water samples. The newly synthesised Fe3O4@G-TEOS-MTMOS showed high potential as adsorbent for OPPs analysis.
The chemotherapy for tuberculosis (TB) is complicated by its long-term treatment, its frequent drug dosing, and the adverse effects of anti-TB drugs. In this study, we have developed two nanocomposites (A and B) by intercalating the anti-TB drug isoniazid (INH) into Zn/Al-layered double hydroxides. The average size of the nanocomposites was found to bê164 nm. The efficacy of the Zn/Al-layered double hydroxides intercalated INH against Mycobacterium tuberculosis was increased by approximately three times more than free INH. The nanocomposites were also found to be active against Gram-positive and -negative bacteria. Compared to the free INH, the nanodelivery formulation was determined to be three times more biocompatible with human normal lung fibroblast MRC-5 cells and 3T3 fibroblast cells at a very high concentration of 50 µg/mL for up to 72 hours. The in vitro release of INH from the Zn/Al-layered double hydroxides was found to be sustained in human body-simulated buffer solutions of pH 4.8 and 7.4. This research is a step forward in making the TB chemotherapy patient friendly.
Combination of bioactive material such as hydroxyapatite (HAp) with antibacterial agents would have great potential to be used as bone implant materials to avert possible bacterial infection that can lead to implant-associated diseases. The present study aimed to develop an antibacterial silver nanoparticle-decorated hydroxyapatite (HAp/AgNPs) nanocomposite using chemical reduction and thermal calcination approaches. In this work, natural HAp that was extracted from chicken bone wastes is used as support matrix for the deposition of silver nanoparticles (AgNPs) to produce HAp/AgNPs nanocomposite. XRD, FESEM-EDX, HRTEM, and XPS analyses confirmed that spherical AgNPs were successfully synthesized and deposited on the surface of HAp particles, and the amount of AgNPs adhered on the HAp surface increased with increasing AgNO3 concentration used. The synthesized HAp/AgNPs nanocomposites demonstrated strong antibacterial activity against Staphylococcus aureus bacteria, where the antibacterial efficiency is relied on the amount and size of deposited AgNPs. In addition, the in vitro bioactivity examination in Hank's balanced salt solution showed that more apatite were grown on the surface of HAp/AgNPs nanocomposite when AgNO3 concentration used >1 wt.%. Such nanocomposite with enhanced bioactivity and antibacterial properties emerged as a promising biomaterial to be applied for dentistry and orthopedic implantology.