Graphene Oxide as a Nanocarrier for a Theranostics Delivery System of Protocatechuic Acid and Gadolinium/Gold Nanoparticles

We have synthesized a graphene oxide (GO)-based theranostic nanodelivery system (GOTS) for magnetic resonance imaging (MRI) using naturally occurring protocatechuic acid (PA) as an anticancer agent and gadolinium (III) nitrate hexahydrate (Gd) as the starting material for a contrast agent,. Gold nanoparticles (AuNPs) were subsequently used as second diagnostic agent. The GO nanosheets were first prepared from graphite via the improved Hummer's protocol. The conjugation of the GO and the PA was done via hydrogen bonding and π-π stacking interactions, followed by surface adsorption of the AuNPs through electrostatic interactions. GAGPA is the name given to the nanocomposite obtained from Gd and PA conjugation. However, after coating with AuNPs, the name was modified to GAGPAu. The physicochemical properties of the GAGPA and GAGPAu nanohybrids were studied using various characterization techniques. The results from the analyses confirmed the formation of the GOTS. The powder X-ray diffraction (PXRD) results showed the diffractive patterns for pure GO nanolayers, which changed after subsequent conjugation of the Gd and PA. The AuNPs patterns were also recorded after surface adsorption. Cytotoxicity and magnetic resonance imaging (MRI) contrast tests were also carried out on the developed GOTS. The GAGPAu was significantly cytotoxic to the human liver hepatocellular carcinoma cell line (HepG2) but nontoxic to the standard fibroblast cell line (3T3). The GAGPAu also appeared to possess higher T1 contrast compared to the pure Gd and water reference. The GOTS has good prospects of serving as future theranostic platform for cancer chemotherapy and diagnosis.

Carbon-Based Nanomaterials/Allotropes: A Glimpse of Their Synthesis, Properties and Some Applications

Carbon in its single entity and various forms has been used in technology and human life for many centuries. Since prehistoric times, carbon-based materials such as graphite, charcoal and carbon black have been used as writing and drawing materials. In the past two and a half decades or so, conjugated carbon nanomaterials, especially carbon nanotubes, fullerenes, activated carbon and graphite have been used as energy materials due to their exclusive properties. Due to their outstanding chemical, mechanical, electrical and thermal properties, carbon nanostructures have recently found application in many diverse areas; including drug delivery, electronics, composite materials, sensors, field emission devices, energy storage and conversion, etc. Following the global energy outlook, it is forecasted that the world energy demand will double by 2050. This calls for a new and efficient means to double the energy supply in order to meet the challenges that forge ahead. Carbon nanomaterials are believed to be appropriate and promising (when used as energy materials) to cushion the threat. Consequently, the amazing properties of these materials and greatest potentials towards greener and environment friendly synthesis methods and industrial scale production of carbon nanostructured materials is undoubtedly necessary and can therefore be glimpsed as the focal point of many researchers in science and technology in the 21st century. This is based on the incredible future that lies ahead with these smart carbon-based materials. This review is determined to give a synopsis of new advances towards their synthesis, properties, and some applications as reported in the existing literatures.

Improved Anticancer Effect of Magnetite Nanocomposite Formulation of GALLIC Acid (Fe₃O₄-PEG-GA) Against Lung, Breast and Colon Cancer Cells

Lung cancer, breast cancer and colorectal cancer are the most prevalent fatal types of cancers globally. Gallic acid (3,4,5-trihydroxybenzoic acid) is a bioactive compound found in plants and foods, such as white tea, witch hazel and it has been reported to possess anticancer, antioxidant and anti-inflammatory properties. In this study we have redesigned our previously reported anticancer nanocomposite formulation with improved drug loading based on iron oxide magnetite nanoparticles coated with polyethylene glycol and loaded with anticancer drug gallic acid (Fe₃O₄-PEG-GA). The in vitro release profile and percentage drug loading were found to be better than our previously reported formulation. The anticancer activity of pure gallic acid (GA), empty carrier (Fe₃O₄-PEG) nanocarrier and of anticancer nanocomposite (Fe₃O₄-PEG-GA) were screened against human lung cancer cells (A549), human breast cancer cells (MCF-7), human colon cancer cells (HT-29) and normal fibroblast cells (3T3) after incubation of 24, 48 and 72 h using (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) MTT assay. The designed formulation (Fe₃O₄-PEG-GA) showed better anticancer activity than free gallic acid (GA). The results of the in vitro studies are highly encouraging to conduct the in vivo studies.

Synthesis of (Hexaconazole-Zinc/Aluminum-Layered Double Hydroxide Nanocomposite) Fungicide Nanodelivery System for Controlling Ganoderma Disease in Oil Palm

A fungicide, hexaconazole was successfully intercalated into the intergalleries of zinc/aluminum-layered double hydroxide (ZALDH) using the ion-exchange method. Due to the intercalation of hexaconazole, the basal spacing of the ZALDH was increased from 8.7 Å in ZALDH to 29.4 Å in hexaconazole-intercalated ZALDH (HZALDH). The intercalation of hexaconazole into the interlayer of the nanocomposite was confirmed using the Fourier-transform infrared (FTIR) study. This supramolecular chemistry intercalation process enhanced the thermal stability of the hexaconazole moiety. The fungicide loading was estimated to be 51.8%. The nanodelivery system also shows better inhibition toward the Ganoderma boninense growth than the counterpart, free hexaconazole. The results from this work have a great potential to be further explored for combating basal stem rot (BSR) disease in oil palm plantation.

Induction of a robust immune response against avian influenza virus following transdermal inoculation with H5-DNA vaccine formulated in modified dendrimer-based delivery system in mouse model

This study was aimed to evaluate the immunogenicity of recombinant plasmid deoxyribonucleic acid (DNA), pBud-H5-green fluorescent protein (GFP)-interferon-regulatory factor (IRF)3 following delivery using polyamidoamine (PAMAM) dendrimer and transactivator of transcription (TAT)-conjugated PAMAM dendrimer as well as the effect of IRF3 as the genetic adjuvant. BALB/c mice were vaccinated transdermally with pBud-H5-GFP, PAMAM/pBud-H5-GFP, TAT-PAMAM/pBud-H5-GFP, and TAT-PAMAM/pBud-H5-GFP-IRF3. The expression analysis of H5 gene from the blood by using quantitative real-time reverse transcriptase polymerase chain reaction confirmed the ability of PAMAM dendrimer as a carrier for gene delivery, as well as the ability of TAT peptide to enhance the delivery efficiency of PAMAM dendrimer. Mice immunized with modified PAMAM by TAT peptide showed higher hemagglutination inhibition titer, and larger CD3⁺/CD4⁺ T cells and CD3⁺/CD8⁺ T cells population, as well as the production of cytokines, namely, interferon (IFN)-γ, interleukin (IL)-2, IL-15, IL-12, IL-6, and tumor necrosis factor-α compared with those immunized with native PAMAM. These results suggest that the function of TAT peptide as a cell-penetrating peptide is able to enhance the gene delivery, which results in rapid distribution of H5 in the tissues of the immunized mice. Furthermore, pBud-H5-GFP co-expressing IRF3 as a genetic adjuvant demonstrated the highest hemagglutination inhibition titer besides larger CD3⁺/CD4⁺ and CD3⁺/CD8⁺ T cells population, and strong Th1-like cytokine responses among all the systems tested. In conclusion, TAT-PAMAM dendrimer-based delivery system with IRF3 as a genetic adjuvant is an attractive transdermal DNA vaccine delivery system utilized to evaluate the efficacy of the developed DNA vaccine in inducing protection during challenge with virulent H5N1 virus.

Development of Tat-Conjugated Dendrimer for Transdermal DNA Vaccine Delivery

PURPOSE

In order to enhance cellular uptake and to facilitate transdermal delivery of DNA vaccine, polyamidoamine (PAMAM) dendrimers conjugated with HIV transactivator of transcription (TAT) was developed.

METHODS

First, the plasmid DNA (pIRES-H5/GFP) nanoparticle was formulated using PAMAM dendrimer and TAT peptide and then characterized for surface charge, particle size, DNA encapsulation and protection of the pIRES-H5/GFP DNA plasmid to enzymatic digestion. Subsequently, the potency of the TAT-conjugated dendrimer for gene delivery was evaluated through in vitro transfection into Vero cells followed by gene expression analysis including western blotting, fluorescent microscopy and PCR. The effect of the TAT peptide on cellular uptake of DNA vaccine was studied by qRT-PCR and flow cytometry. Finally, the ability of TAT-conjugated PAMAM dendrimer for transdermal delivery of the DNA plasmid was assessed through artificial membranes followed by qRT-PCR and flow cytometry.

RESULTS

TAT-conjugated PAMAM dendrimer showed the ability to form a compact and nanometre-sized polyplexes with the plasmid DNA, having the size range of 105 to 115 nm and a positive charge of +42 to +45 mV over the N/P ratio of 6:1(+/-).  In vitro transfection analysis into Vero cells confirms the high potency of TAT-conjugated PAMAM dendrimer to enhance the cellular uptake of DNA vaccine.  The permeability value assay through artificial membranes reveals that TAT-conjugated PAMAM has more capacity for transdermal delivery of the DNA compared to unmodified PAMAM dendrimer (P<0.05).

CONCLUSIONS

The findings of this study suggest that TAT-conjugated PAMAM dendrimer is a promising non-viral vector for transdermal use.This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

Novel Anti-Tuberculosis Nanodelivery Formulation of Ethambutol with Graphene Oxide

Tuberculosis (TB) is a bacterial disease responsible for millions of infections and preventable deaths each year. Its treatment is complicated by patients' noncompliance due to dosing frequency, lengthy treatment, and adverse side effects associated with current chemotherapy. However, no modifications to the half-a-century old standard chemotherapy have been made based on a nanoformulation strategy to improve pharmacokinetic efficacy. In this study, we have designed a new nanodelivery formulation, using graphene oxide as the nanocarrier, loaded with the anti-TB antibiotic, ethambutol. The designed formulation was characterized using a number of molecular analytical techniques. It was found that sustained release of the drug resulted in better bioavailability. In addition, the designed formulation demonstrated high biocompatibility with mouse fibroblast cells. The anti-TB activity of the nanodelivery formulation was determined using whole-cell resazurin microtiter plate assay, modified-spot culture growth inhibition assay, and biofilm inhibition assay. The nanodelivery formulation showed good anti-mycobacterial activity. The anti-mycobacterial activity of Ethambutol was unaffected by the drug loading and release process. The results of this study demonstrated the potential of this new nanodelivery formulation strategy to be considered for modifying existing chemotherapy to yield more efficacious antibiotic treatment against TB.

Nano-Formulation of Ethambutol with Multifunctional Graphene Oxide and Magnetic Nanoparticles Retains Its Anti-Tubercular Activity with Prospects of Improving Chemotherapeutic Efficacy

Tuberculosis (TB) is a dreadful bacterial disease, infecting millions of human and cattle every year worldwide. More than 50 years after its discovery, ethambutol continues to be an effective part of the World Health Organization's recommended frontline chemotherapy against TB. However, the lengthy treatment regimens consisting of a cocktail of antibiotics affect patient compliance. There is an urgent need to improve the current therapy so as to reduce treatment duration and dosing frequency. In this study, we have designed a novel anti-TB multifunctional formulation by fabricating graphene oxide with iron oxide magnetite nanoparticles serving as a nano-carrier on to which ethambutol was successfully loaded. The designed nanoformulation was characterised using various analytical techniques. The release of ethambutol from anti-TB multifunctional nanoparticles formulation was found to be sustained over a significantly longer period of time in phosphate buffer saline solution at two physiological pH (7.4 and 4.8). Furthermore, the nano-formulation showed potent anti-tubercular activity while remaining non-toxic to the eukaryotic cells tested. The results of this in vitro evaluation of the newly designed nano-formulation endorse its further development in vivo.

Facile aerobic construction of iron based ferromagnetic nanostructures by a novel microbial nanofactory isolated from tropical freshwater wetlands

BACKGROUND

Iron based ferromagnetic nanoparticles (IONP) have found a wide range of application in microelectronics, chemotherapeutic cell targeting, and as contrast enhancers in MRI. As such, the design of well-defined monodisperse IONPs is crucial to ensure effectiveness in these applications. Although these nanostructures are currently manufactured using chemical and physical processes, these methods are not environmentally conducive and weigh heavily on energy and outlays. Certain microorganisms have the innate ability to reduce metallic ions in aqueous solution and generate nano-sized IONP's with narrow size distribution. Harnessing this potential is a way forward in constructing microbial nanofactories, capable of churning out high yields of well-defined IONP's with physico-chemical characteristics on par with the synthetically produced ones.

RESULTS

In this work, we report the molecular characterization of an actinomycetes, isolated from tropical freshwater wetlands sediments, that demonstrated rapid aerobic extracellular reduction of ferric ions to generate iron based nanoparticles. Characterization of these nanoparticles was carried out using Field Emission Scanning Electron Microscope with energy dispersive X-ray spectroscopy (FESEM-EDX), Field Emission Transmission Electron Microscope (FETEM), Ultraviolet-Visible (UV-Vis) Spectrophotometer, dynamic light scattering (DLS) and Fourier transform infrared spectroscopy (FTIR). This process was carried out at room temperature and humidity and under aerobic conditions and could be developed as an environmental friendly, cost effective bioprocess for the production of IONP's.

CONCLUSION

While it is undeniable that iron reducing microorganisms confer a largely untapped resource as potent nanofactories, these bioprocesses are largely anaerobic and hampered by the low reaction rates, highly stringent microbial cultural conditions and polydispersed nanostructures. In this work, the novel isolate demonstrated rapid, aerobic reduction of ferric ions in its extracellular matrix, resulting in IONPs of relatively narrow size distribution which are easily extracted and purified without the need for convoluted procedures. It is therefore hoped that this isolate could be potentially developed as an effective nanofactory in the future.

Oil Palm Waste-Based Precursors as a Renewable and Economical Carbon Sources for the Preparation of Reduced Graphene Oxide from Graphene Oxide

Herein, a new approach was proposed to produce reduced graphene oxide (rGO) from graphene oxide (GO) using various oil palm wastes: oil palm leaves (OPL), palm kernel shells (PKS) and empty fruit bunches (EFB). The effect of heating temperature on the formation of graphitic carbon and the yield was examined prior to the GO and rGO synthesis. Carbonization of the starting materials was conducted in a furnace under nitrogen gas for 3 h at temperatures ranging from 400 to 900 °C and a constant heating rate of 10 °C/min. The GO was further synthesized from the as-carbonized materials using the ‘improved synthesis of graphene oxide’ method. Subsequently, the GO was reduced by low-temperature annealing reduction at 300 °C in a furnace under nitrogen gas for 1 h. The I_G/I_D ratio calculated from the Raman study increases with the increasing of the degree of the graphitization in the order of rGO from oil palm leaves (rGOOPL) < rGO palm kernel shells (rGOPKS) < rGO commercial graphite (rGOCG) < rGO empty fruit bunches (rGOEFB) with the I_G/I_D values of 1.06, 1.14, 1.16 and 1.20, respectively. The surface area and pore volume analyses of the as-prepared materials were performed using the Brunauer Emmett Teller-Nitrogen (BET-N₂) adsorption-desorption isotherms method. The lower BET surface area of 8 and 15 m² g⁻¹ observed for rGOCG and rGOOPL, respectively could be due to partial restacking of GO layers and locally-blocked pores. Relatively, this lower BET surface area is inconsequential when compared to rGOPKS and rGOEFB, which have a surface area of 114 and 117 m² g⁻¹, respectively.

Gadolinium-based layered double hydroxide and graphene oxide nano-carriers for magnetic resonance imaging and drug delivery

Gadolinium (Gd)-based contrasts remain one of the most accepted contrast agents for magnetic resonance imaging, which is among the world most recognized noninvasive techniques employed in clinical diagnosis of patients. At ionic state, Gd is considered toxic but less toxic in chelate form. A variety of nano-carriers, including gadolinium oxide (Gd₂O₃) nanoparticles have been used by researchers to improve the T1 and T2 contrasts of MR images. Even more recently, a few researchers have tried to incorporate contrast agents simultaneously with therapeutic agents using single nano-carrier for theranostic applications. The benefit of this concept is to deliver the drugs, such as anticancer drugs and at the same time to observe what happens to the cancerous cells. The delivery of both agents occurs concurrently. In addition, the toxicity of the anticancer drugs as well as the contrast agents will be significantly reduced due to the presence of the nano-carriers. The use of graphene oxide (GO) and layered double hydroxides (LDH) as candidates for this purpose is the subject of current research, due to their low toxicity and biocompatibility, which have the capacity to be used in theranostic researches. We review here, some of the key features of LDH and GO for simultaneous drugs and diagnostic agents delivery systems for use in theranostics applications.

Surface-functionalized cockle shell-based calcium carbonate aragonite polymorph as a drug nanocarrier

Calcium carbonate aragonite polymorph nanoparticles derived from cockle shells were prepared using surface functionalization method followed by purification steps. Size, morphology, and surface properties of the nanoparticles were characterized using transmission electron microscopy, field emission scanning electron microscopy, dynamic light scattering, zetasizer, X-ray powder diffraction, and Fourier transform infrared spectrometry techniques. The potential of surface-functionalized calcium carbonate aragonite polymorph nanoparticle as a drug-delivery agent were assessed through in vitro drug-loading test and drug-release test. Transmission electron microscopy, field emission scanning electron microscopy, and particle size distribution analyses revealed that size, morphology, and surface characterization had been improved after surface functionalization process. Zeta potential of the nanoparticles was found to be increased, thereby demonstrating better dispersion among the nanoparticles. Purification techniques showed a further improvement in the overall distribution of nanoparticles toward more refined size ranges <100 nm, which specifically favored drug-delivery applications. The purity of the aragonite phase and their chemical analyses were verified by X-ray powder diffraction and Fourier transform infrared spectrometry studies. In vitro biological response of hFOB 1.19 osteoblast cells showed that surface functionalization could improve the cytotoxicity of cockle shell–based calcium carbonate aragonite nanocarrier. The sample was also sensitive to pH changes and demonstrated good abilities to load and sustain in vitro drug. This study thus indicates that calcium carbonate aragonite polymorph nanoparticles derived from cockle shells, a natural biomaterial, with modified surface characteristics are promising and can be applied as efficient carriers for drug delivery.

Sustained release of anticancer agent phytic acid from its chitosan-coated magnetic nanoparticles for drug-delivery system

Chitosan (CS) iron oxide magnetic nanoparticles (MNPs) were coated with phytic acid (PTA) to form phytic acid-chitosan-iron oxide nanocomposite (PTA-CS-MNP). The obtained nanocomposite and nanocarrier were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, vibrating sample magnetometry, transmission electron microscopy, and thermogravimetric and differential thermogravimetric analyses. Fourier transform infrared spectra and thermal analysis of MNPs and PTA-CS-MNP nanocomposite confirmed the binding of CS on the surface of MNPs and the loading of PTA in the PTA-CS-MNP nanocomposite. The coating process enhanced the thermal stability of the anticancer nanocomposite obtained. X-ray diffraction results showed that the MNPs and PTA-CS-MNP nanocomposite are pure magnetite. Drug loading was estimated using ultraviolet-visible spectroscopy and showing a 12.9% in the designed nanocomposite. Magnetization curves demonstrated that the synthesized MNPs and nanocomposite were superparamagnetic with saturation magnetizations of 53.25 emu/g and 42.15 emu/g, respectively. The release study showed that around 86% and 93% of PTA from PTA-CS-MNP nanocomposite could be released within 127 and 56 hours by a phosphate buffer solution at pH 7.4 and 4.8, respectively, in a sustained manner and governed by pseudo-second order kinetic model. The cytotoxicity of the compounds on HT-29 colon cancer cells was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The HT-29 cell line was more sensitive against PTA-CS-MNP nanocomposite than PTA alone. No cytotoxic effect was observed on normal cells (3T3 fibroblast cells). This result indicates that PTA-CS-MNP nanocomposite can inhibit the proliferation of colon cancer cells without causing any harm to normal cell.

Synthesis and Characterization of Cockle Shell-Based Calcium Carbonate Aragonite Polymorph Nanoparticles with Surface Functionalization

The development of cockle shell-based calcium carbonate aragonite polymorph nanoparticle synthesis method using the technique of mechanical stirring in the presence of dodecyl dimethyl betaine (BS-12) incorporated with surface functionalization demonstrated high homogeneity of sample product with good nanoparticles dispersion. The cockle shell-based calcium carbonate aragonite nanoparticle with functionalized surface was characterized using transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), particle size distribution, pH measurement analysis, Fourier Transform Infrared (FTIR) spectroscopy, and X-ray diffraction (XRD). Surface functionalization was proven to improve the overall size and shape of the nanoparticles and enhance their dispersion properties, preventing coarse agglomeration among nanoparticles in general. The improved method was verified to retain its aragonite crystalline nature. Additionally, surface functionalization did not increase the size of nanoparticles throughout the modification process. This facile preparation using naturally occurring cockle shells as the main source is environmentally friendly because it provides relatively low cost of raw material source as it is abundantly available in nature and has good mineral purity content. Hence, high quality production of surface functionalized cockle shell-based calcium carbonate aragonite polymorph nanoparticles can potentially be exploited and produced on a large scale for various industrial applications, especially for biomedical purposes in the near future.

In vitro drug release characteristic and cytotoxic activity of silibinin-loaded single walled carbon nanotubes functionalized with biocompatible polymers

In this paper, we demonstrate the preparation of silibinin-loaded carbon nanotubes (SWSB) with surface coating agents via non-covalent approach as an effective drug delivery system. The resulting surface-coated SWSB nanocomposites are extensively characterized by Fourier transform infrared (FTIR) and Raman spectroscopies, ultraviolet-visible (UV-Vis) spectrometry and field emission scanning electron microscopy (FESEM). The FTIR and Raman studies show that an additional layer is formed by these coating agents in the prepared nanocomposites during the coating treatment and these results are confirmed by FESEM. Drug loading and release profiles of the coated SWSB nanocomposites in phosphate buffered saline solution at pH 7.4 is evaluated by UV-Vis spectrometry. The in vitro results indicate that the surface-modified nanocomposites, with SB loading of 45 wt%, altered the initial burst and thus, resulted in a more prolonged and sustained release of SB. In addition, these nanocomposites exhibit a pseudo-second-order release kinetic which was driven by the ion exchange between the ionized SWSB and the anions in the release medium. The cytotoxicity effect of the resulting nanocomposites on normal mouse fibroblast cells is evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. It is observed that the surfactant and polymer coating improved the biocompatibility of the SWSB nanocomposites significantly, which deem further exploitation for their application as potential anticancer drug delivery system.

Graphene oxide as a nanocarrier for controlled release and targeted delivery of an anticancer active agent, chlorogenic acid

We have synthesized graphene oxide using improved Hummer's method in order to explore the potential use of the resulting graphene oxide as a nanocarrier for an active anticancer agent, chlorogenic acid (CA). The synthesized graphene oxide and chlorogenic acid-graphene oxide nanocomposite (CAGO) were characterized using Fourier transform infrared (FTIR) spectroscopy, thermogravimetry and differential thermogravimetry analysis, Raman spectroscopy, powder X-ray diffraction (PXRD), UV-vis spectroscopy and high resolution transmission electron microscopy (HRTEM) techniques. The successful conjugation of chlorogenic acid onto graphene oxide through hydrogen bonding and π-π interaction was confirmed by Raman spectroscopy, FTIR analysis and X-ray diffraction patterns. The loading of CA in the nanohybrid was estimated to be around 13.1% by UV-vis spectroscopy. The release profiles showed favourable, sustained and pH-dependent release of CA from CAGO nanocomposite and conformed well to the pseudo-second order kinetic model. Furthermore, the designed anticancer nanohybrid was thermally more stable than its counterpart. The in vitro cytotoxicity results revealed insignificant toxicity effect towards normal cell line, with a viability of >80% even at higher concentration of 50μg/mL. Contrarily, CAGO nanocomposite revealed enhanced toxic effect towards evaluated cancer cell lines (HepG2 human liver hepatocellular carcinoma cell line, A549 human lung adenocarcinoma epithelial cell line, and HeLa human cervical cancer cell line) compared to its free form.

Effect of Gelatin-Stabilized Copper Nanoparticles on Catalytic Reduction of Methylene Blue

The synthesis of copper nanoparticles was carried out with gelatin as a stabilizer by reducing CuSO₄.5H₂O ions using hydrazine. Ascorbic acid and aqueous NaOH were also used as an antioxidant and pH controller, respectively. The effects of NaOH, hydrazine, and concentration of gelatin as stabilizer were studied. The synthesized copper nanoparticles were characterized by UV-vis spectroscopy, XRD, zeta potential measurements, FTIR, EDX, FESEM, and TEM. The formation of CuNPs@Gelatin is initially confirmed by UV-vis spectroscopic analysis with the characteristic band at 583 nm. XRD and TEM reports revealed that CuNPs@Gelatin (0.75 wt.%) is highly crystalline and spherical in shape with optimum average size of 4.21 ± 0.95 nm. FTIR studies indicated the presence of amide group on the surface of the CuNPs indicating the stability of CuNPs which is further supported by zeta potential measurements with the negative optimum value of -37.90 ± 0.6 mV. The CuNPs@G4 showed a good catalytic activity against methylene blue (MB) reduction using NaBH₄ as a reducing agent in an aqueous solution. The best enhanced properties of CuNPs@G4 were found for the 0.75 wt.% gelatin concentration. Thermodynamic parameters (ΔH and ΔS) indicate that under the studied temperature, the reduction of MB by CuNPs@G4 is not feasible and had endothermic in nature.

Synthesis, characterization, and efficacy of antituberculosis isoniazid zinc aluminum-layered double hydroxide based nanocomposites

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.

Biocompatible polymers coated on carboxylated nanotubes functionalized with betulinic acid for effective drug delivery

Chemically functionalized carbon nanotubes are highly suitable and promising materials for potential biomedical applications like drug delivery due to their distinct physico-chemical characteristics and unique architecture. However, they are often associated with problems like insoluble in physiological environment and cytotoxicity issue due to impurities and catalyst residues contained in the nanotubes. On the other hand, surface coating agents play an essential role in preventing the nanoparticles from excessive agglomeration as well as providing good water dispersibility by replacing the hydrophobic surfaces of nanoparticles with hydrophilic moieties. Therefore, we have prepared four types of biopolymer-coated single walled carbon nanotubes systems functionalized with anticancer drug, betulinic acid in the presence of Tween 20, Tween 80, polyethylene glycol and chitosan as a comparative study. The Fourier transform infrared spectroscopy studies confirm the bonding of the coating molecules with the SWBA and these results were further supported by Raman spectroscopy. All chemically coated samples were found to release the drug in a slow, sustained and prolonged fashion compared to the uncoated ones, with the best fit to pseudo-second order kinetic model. The cytotoxic effects of the synthesized samples were evaluated in mouse embryonic fibroblast cells (3T3) at 24, 48 and 72 h. The in vitro results reveal that the cytotoxicity of the samples were dependent upon the drug release profiles as well as the chemical components of the surface coating agents. In general, the initial burst, drug release pattern and cytotoxicity could be well-controlled by carefully selecting the desired materials to suit different therapeutic applications.

Folic acid targeted Mn:ZnS quantum dots for theranostic applications of cancer cell imaging and therapy

In this study, we synthesized a multifunctional nanoparticulate system with specific targeting, imaging, and drug delivering functionalities by following a three-step protocol that operates at room temperature and solely in aqueous media. The synthesis involves the encapsulation of luminescent Mn:ZnS quantum dots (QDs) with chitosan not only as a stabilizer in biological environment, but also to further provide active binding sites for the conjugation of other biomolecules. Folic acid was incorporated as targeting agent for the specific targeting of the nanocarrier toward the cells overexpressing folate receptors. Thus, the formed composite emits orange-red fluorescence around 600 nm and investigated to the highest intensity at Mn(2+) doping concentration of 15 at.% and relatively more stable at low acidic and low alkaline pH levels. The structural characteristics and optical properties were thoroughly analyzed by using Fourier transform infrared, X-ray diffraction, dynamic light scattering, ultraviolet-visible, and fluorescence spectroscopy. Further characterization was conducted using thermogravimetric analysis, high-resolution transmission electron microscopy, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray fluorescence, and X-ray photoelectron spectroscopy. The cell viability and proliferation studies by means of MTT assay have demonstrated that the as-synthesized composites do not exhibit any toxicity toward the human breast cell line MCF-10 (noncancer) and the breast cancer cell lines (MCF-7 and MDA-MB-231) up to a 500 µg/mL concentration. The cellular uptake of the nanocomposites was assayed by confocal laser scanning microscope by taking advantage of the conjugated Mn:ZnS QDs as fluorescence makers. The result showed that the functionalization of the chitosan-encapsulated QDs with folic acid enhanced the internalization and binding affinity of the nanocarrier toward folate receptor-overexpressed cells. Therefore, we hypothesized that due to the nontoxic nature of the composite, the as-synthesized nanoparticulate system can be used as a promising candidate for theranostic applications, especially for a simultaneous targeted drug delivery and cellular imaging.

Evaluation of Controlled-Release Property and Phytotoxicity Effect of Insect Pheromone Zinc-Layered Hydroxide Nanohybrid Intercalated with Hexenoic Acid

A controlled release formulation for the insect pheromone hexenoic acid (HE) was successfully developed using zinc-layered hydroxide (ZLH) as host material through a simple coprecipitation technique, resulting in the formation of inorganic-organic nanolayered material with sustained release properties. The release of HE from its nanohybrid was found to occur in a controlled manner, governed by a pseudo-second order kinetics model. The maximum amount of HE released from the nanocomposite into solutions at pH 4, 6.5, and 8 was found to be 84, 73, and 83% for 1100 min, respectively. The hexenoate zinc-layered hydroxide nanomaterial (HEN) was found to be nontoxic for plants when green beans and wheat seeds were successfully germinated in all HEN concentrations tested in the experiment, with higher percentage of seed germination and higher radical seed growth as compared to its counter anion, HE. ZLH can be a promising carrier for insect pheromone toward a new generation of environmentally safe pesticide nanomaterial for crop protection.