Hybrid Nanosystems Research Articles

One step production of Se doped carbon dots for rapid sensing of tetracycline in real water sample

In the present decade, the utilization of antibiotics at augmented rate has caused harmful environmental pollution. The resistance rate of bacteria against antibiotics has become faster due to excessive employment of antibiotics. Therefore, it is mandatory to develop a new, sustainable and environment friendly nanohybrid system which can easily detect antibiotic especially tetracycline. It is prevalently found drug pollutant which can easily contaminate food, aquatic species and human health. While keeping all the facts during consideration, a simple and one step scheme is followed for the development of selenium supported carbon dots (Se@CDs) nano hybrids by utilizing commonly available natural sugars such as sucrose, fructose and glucose as a reducing and stabilizing agent. The CDs were prepared from the waste coconut husk. The developed nano-hybrid exhibits excellent optical and emission properties which suggest their further applications. Additionally, different analytical studies have been carried out to evaluate their physicochemical properties. Due to their outstanding analytical behavior, they have been successfully utilized in the sensitive and specific detection of tetracycline (TC) in presence of different interfering ions. The glucose derived Se@CDs shows maximum quenching effect towards TC. The value of detection limit and binding constant were found to be 155 nM and 517 nM −1 . Further, their recovery studies have been carried out in different real samples. The obtained findings suggest that the developed Se@CDs can be successfully explored in biological fields. • Development of Se doped carbon dots have been carried out by using three natural reducing sugars. • Different analytical techniques have been performed to evaluate the physicochemical properties of prepared Se@CDs nanohybrid. • The developed glucose derived Se@CDs have been found highly effective in the fluorescence quenching of tetracycline. • The value of detection limit of G-Se@CDs for tetracycline sensing was found to be 155 nM.

Controlling effect of hydroxyl phenyl aminopropyl cationic surfactants on the catalytic and biological performance of AgNPs

Three Hydroxy phenyl aminopropyl cationic surfactants with different carbon tail length; 8 (HPAPO), 12 (HPAPD), and 16 (HPAPH) have been synthesized successfully. The hydrophobic tail showed a pivotal impact on the morphological structure of the prepared silver nanoparticles (AgNPs) in terms of particles size, stability and yields as confirmed by TEM, DLS and UV-Vis spectroscopy measurements. The prepared AgNPs by HPAPH surfactant has a uniform structure with smaller particles size, and higher stability compared to that prepared by shorter chain length surfactants HPAPO and HPAPD. The HPAPH surfactant lead to formation AgNPs with size 12.9 ± 3.5 nm with high zeta potential 75.9± 6.4 mV indicating for highest stability. The surface and thermodynamic properties of the HPAPO, HPAPD and HPAPH surfactants are dependent on temperature and the hydrophobic tail length. The adsorption affinity is enhanced as temperature or chain length is increased. Increasing the surfactant hydrophobic tail or the solution temperature lead to decreasing the critical micelle concentration (CMC) of the surfactant solution. The hydrophobic chain exhibited a significant impact on the catalytic activity of the AgNPs toward removal some toxic pollutants such as methylene blue (MB) and p-nitrophenol (p-NP). The synthesized AgNPs using longer surfactant tail (HPAPH/AgNPs) showed highest catalytic activity compared to that prepared via shorter chain, which consider a promising study in terms of surfactant chain influence on the catalytic performance. The prepared cationic surfactants have good biological activity which is enhanced in case of in-cooperation with AgNPs. Both HPAPH Surfactant and HPAPH/AgNPs nano-hybrid system trigger maximum inhibition zone against all inspected microorganism, compared to surfactant with shorter chain.

Recent Advances in Multimodal Molecular Imaging of Cancer Mediated by Hybrid Magnetic Nanoparticles.

Cancer is the second leading cause of death in the world, which is why it is so important to make an early and very precise diagnosis to obtain a good prognosis. Thanks to the combination of several imaging modalities in the form of the multimodal molecular imaging (MI) strategy, a great advance has been made in early diagnosis, in more targeted and personalized therapy, and in the prediction of the results that will be obtained once the anticancer treatment is applied. In this context, magnetic nanoparticles have been positioned as strong candidates for diagnostic agents as they provide very good imaging performance. Furthermore, thanks to their high versatility, when combined with other molecular agents (for example, fluorescent molecules or radioisotopes), they highlight the advantages of several imaging techniques at the same time. These hybrid nanosystems can be also used as multifunctional and/or theranostic systems as they can provide images of the tumor area while they administer drugs and act as therapeutic agents. Therefore, in this review, we selected and identified more than 160 recent articles and reviews and offer a broad overview of the most important concepts that support the synthesis and application of multifunctional magnetic nanoparticles as molecular agents in advanced cancer detection based on the multimodal molecular imaging approach.

Incorporating silver nanoshell-coated mesoporous silica nanoparticles improves physicochemical and antimicrobial properties of chitosan films

Tailoring nanomaterials with tunable properties is of great importance to develop multifunctional candidates in the biomedical field. In the present study, we aimed to develop a promising nano-hybrid system composed of chitosan (CS) and mesoporous silica nanoparticles with a silver nanoshell coat (CS-AgMSNs).The physicochemical properties of CS-AgMSNs films were characterized using various techniques. Further, the mechanical properties of CS-AgMSNs were evaluated and compared with those of undoped CS film. Moreover, the antimicrobial activities of CS-AgMSNs (with different concentrations) were assessed against E-coli, S. aureus, C. albicans, and A. niger.Our results demonstrated that increasing the concentrations of doped AgMSNs (10 to 40 mg) in CS films lowered their transparency and blocked light transmission effectively. The measured elastic modulus of CS-AgMSNs films (20 and 30 mg) showed a decrease in the stiffness of CS films. Also, the elongation at break for CS-AgMSNs (40 mg) indicated a better flexibility. CS-AgMSNs films (10–40 mg) showed an enhanced antimicrobial activity in a concentration-dependent manner compared to undoped CS films.Collectively, the results suggest that our nano-hybrid CS-AgMSNs matrix has unique and promising properties, and holds potential for use in the biomedical field, food packaging, and textile industry.

Pluronic-loaded Silver Nanoparticles/Photosensitizers Nanohybrids: Influence of the Polymer Chain Length on Metal-enhanced Photophysical Properties.

Silver nanoparticles (AgNPs) are incredibly versatile nanostructures that more recently have been exploited to create advanced optoelectronic materials due enhancement of local magnetic field after its irradiation. However, the use of AgNPs as nanoantennas to amplify photophysical properties of close photosensitizer (PS) molecules in photodynamic therapy is still underexplored. The reason for that is the difficulty to control crucial parameters such as silver-PS distance in aqueous solution. In this scenario, here we propose a nanohybrid system where AgNP/PS distance is controlled by a thin layer of different Pluronic copolymers. The controllable distance and aqueous stability of proposed nanohybrids allow a tunable enhancement of fluorescence emission and singlet oxygen generation of some selected PS molecules. A detailed mechanism investigation demonstrated that the observed metal-enhanced photophysics is due to magnetic field enhancement close to AgNP surface (AgNP/PS distance-controlled effect) and the resonant coupling of AgNP hot electrons and HOMO-LUMO energies of the PS (AgNP/PS spectral overlap-controlled effect). These results show that the rational design in engineering new nanohybrid structures allowed photophysical improvement of PS molecules in aqueous solution in a tunable way and point out Pluronic-based AgNP/PS nanohybrids as a smart material for further developments aiming at theranostic applications in photodynamic therapy.

Enhanced sunlight driven photocatalytic activity of In2S3 nanosheets functionalized MoS2 nanoflowers heterostructures

Visible light-sensitive 2D-layered based photocatalytic systems have been proven one of the effective recent trends. We report the preparation of a 2D-layered based In2S3–MoS2 nanohybrid system through a facile hydrothermal method, capable of efficiently degrading of organic contaminants with remarkable efficiency. Transmission electron microscopy (TEM) results inferred the attachment of 2D-layered In2S3 sheets with the MoS2 nanoflakes. Field emission SEM studies with chemical mapping confirm the uniform distribution of Mo, In, and S atoms in the heterostructure, affirming sample uniformity. X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy results confirm the appearance of 2H-MoS2 and β-In2S3 in the grown heterostructures. UV-DRS results reveal a significant improvement in the optical absorbance and significant bandgap narrowing (0.43 eV) in In2S3–MoS2 nanohybrid compared to pristine In2S3 nanosheets in the visible region. The effective bandgap narrowing facilitates the charge transfer between MoS2 and In2S3 and remarkably improves the synergistic effect. Effective bandgap engineering and improved optical absorption of In2S3–MoS2 nanohybrids are favorable for enhancing their charge separation and photocatalytic ability. The photocatalytic decomposition efficiency of the pristine In2S3 nanosheets and In2S3–MoS2 nanohybrids sample is determined by the decomposing of methylene blue and oxytetracycline molecules under natural sunlight. The optimized In2S3–MoS2 nanohybrids can decompose 97.67% of MB and 76.3% of OTC-HCl molecules solution in 8 min and 40 min of exposure of sunlight respectively. 2D-layered In2S3-MoS2 nanohybrids reveal the tremendous remediation performance towards chemical contaminations and pharmaceutical waste, which indicates their applicability in industrial and practical applications.

A nanohybrid system based on covalently functionalized graphene quantum dots with dithienopyrrole derivative for the sensitive and selective fluorometric detection of Pb2+ ions.

Recently graphene quantum dot (GQD) based nanohybrid materials have received much attention. Herein, a highly fluorescent biocompatible GQD and N-functionalized dithienopyrrole (DTP-PPD) modified nanohybrid system was fabricated (DTP-PPD-fn-GQD) for the first time. Modification resulted in stable fluorescence with a quantum yield of approximately 22% and 36 nm redshift compared to unmodified GQD. The apparent bandgap tuning along with fluorescence property changes was investigated by cyclic voltammetry measurements and density functional theory studies. This water-soluble system was then applied for the sensitive and selective detection of Pb2+ ions. As a result of a specific interaction towards Pb2+ ions, the fluorescence intensity was quenched. The detection limit is found to be 1.02 nM within the linear range of 3 to 30 nM. Finally, the feasibility of the developed probe was tested with real samples of water. Chemically modified GQDs are already widely exploited for Pb2+ sensing, whereas GQD/thiophene-based nanohybrid systems are less utilized. This newly developed nanohybrid of GQD (DTP-PPD-fn-GQD) has excellent fluorescence properties and bandgap tunability. Moreover, effective fluorometric sensing of Pb2+ ions in an aqueous medium is well investigated. This gives more insight into developing GQD-based highly promising nanohybrid colorimetric as well as fluorescent sensors.

Phospholipid/zein hybrid nanoparticles as promising carriers for the protection and delivery of all-trans retinoic acid

A totally biodegradable mixed system made up of phospholipids and zein was developed in order to effectively improve the photostability of all-trans retinoic acid (ATRA) preserving its pharmacological properties. Photon correlation spectroscopy showed that the formulation obtained using phospholipon 85G and zein at a ratio of 7:3 w/w was characterized by an average diameter of less than 200 nm, a narrow size distribution and a significant time- and temperature-dependent stability. The use of specific cryoprotectants such as mannose and glucose favoured the long-term storage of the nanocarriers after the freeze-drying procedure. The nanoparticles increased the stability of the ATRA against photochemical degradation with respect to the free drug and its antitumor effect was preserved as a consequence of the cell uptake of the colloidal systems. The results demonstrate the potential of the proposed hybrid nanosystems to provide a high level of stabilization for sensitive and labile antitumor compounds.

Antimicrobial Activity of Curcumin in Nanoformulations: A Comprehensive Review.

Curcumin (CUR) is a natural substance extracted from turmeric that has antimicrobial properties. Due to its ability to absorb light in the blue spectrum, CUR is also used as a photosensitizer (PS) in antimicrobial Photodynamic Therapy (aPDT). However, CUR is hydrophobic, unstable in solutions, and has low bioavailability, which hinders its clinical use. To circumvent these drawbacks, drug delivery systems (DDSs) have been used. In this review, we summarize the DDSs used to carry CUR and their antimicrobial effect against viruses, bacteria, and fungi, including drug-resistant strains and emergent pathogens such as SARS-CoV-2. The reviewed DDSs include colloidal (micelles, liposomes, nanoemulsions, cyclodextrins, chitosan, and other polymeric nanoparticles), metallic, and mesoporous particles, as well as graphene, quantum dots, and hybrid nanosystems such as films and hydrogels. Free (non-encapsulated) CUR and CUR loaded in DDSs have a broad-spectrum antimicrobial action when used alone or as a PS in aPDT. They also show low cytotoxicity, in vivo biocompatibility, and improved wound healing. Although there are several in vitro and some in vivo investigations describing the nanotechnological aspects and the potential antimicrobial application of CUR-loaded DDSs, clinical trials are not reported and further studies should translate this evidence to the clinical scenarios of infections.

131I-Labeled Multifunctional Polyethylenimine/Doxorubicin Complexes with pH-Controlled Cellular Uptake Property for Enhanced SPECT Imaging and Chemo/Radiotherapy of Tumors.

IntroductionSmart theranostic nanosystems own a favorable potential to improve internalization within tumor while avoiding nonspecific interaction with normal tissues. However, development of this type of theranostic nanosystems is still a challenge.MethodsIn this study, we developed the iodine-131 (131I)-labeled multifunctional polyethylenimine (PEI)/doxorubicin (DOX) complexes with pH-controlled cellular uptake property for enhanced single-photon emission computed tomography (SPECT) imaging and chemo/radiotherapy of tumors. Alkoxyphenyl acylsulfonamide (APAS), a typical functional group that could achieve improved cellular uptake of its modified nanoparticles, was utilized to conjugate onto the functional PEI pre-modified with polyethylene glycol (PEG) with terminal groups of monomethyl ether and N-hydroxysuccinimide (mPEG-NHS), PEG with terminal groups of maleimide and succinimidyl valerate (MAL-PEG-SVA) through sulfydryl of APAS and MAL moiety of MAL-PEG-SVA. This was followed by conjugation with 3-(4’-hydroxyphenyl)propionic acid-OSu (HPAO), acetylating leftover amines of PEI, complexing DOX and labeling 131I to generate the theranostic nanosystems.ResultsThe synthesized theranostic nanosystems exhibit favorable water solubility and stability. Every functional PEI can complex approximately 12.4 DOX, which could sustainably release of DOX following a pH-dependent manner. Remarkably, due to the surface modification of APAS, the constructed theranostic nanosystems own the capacity to achieve pH-responsive charge conversion and further lead to improved cellular uptake in cancer cells under slightly acidic condition. Above all, based on the coexistence of DOX and radioactive 131I in the single nanosystem, the synthesized nanohybrid system could afford enhanced SPECT imaging and chemo/radioactive combination therapy of cancer cells in vitro and xenografted tumor model in vivo.DiscussionThe developed smart nanohybrid system provides a novel strategy to improve the tumor theranostic efficiency and may be applied for different types of cancer.

(Invited) Light Emission Modulation from Individual Single-Walled Carbon Nanotubes By Chromophore Encapsulation

The one-dimensional structure of single-walled carbon nanotubes (NT) display optical absorption and near-infrared emission (thanks to van Hove singularities). Chromophore encapsulation into host single-walled carbon nanotubes allows to create hybrid nano-systems with tunable opto-electronic properties. Up to now, we have been confining different kinds of chromophores,1-4 absorbing from the blue/ green (400/500 nm) range (tetracyanoquinodimethane (TNCQ), quaterthiophene derivatives (4T) and tetramethyl-paraphenylenediamine (TMPD)) to the red (700 nm) range (phthalocyanine (MPc)). In addition then can be either electron donor (4T, TMPD) or acceptor (TNCQ).In this study, we investigate, at both the macroscopic and the individual scales, the electronic and the optical properties of our hybrid systems by means of Raman and photoluminescence spectroscopies.Photoluminescence experiments clearly demonstrate changes on the emission properties after encapsulation. The intensities can be increased or reduced depending on the nature of the confined chromophores (electron donor or acceptor) and on the NT diameter.From Raman measurements, a significant charge transfer from the confined dye to the nanotube is evidenced. The main relevant parameters that govern the charge transfer are the nanotube diameter and the nature of the chromophores (electron donor or acceptor).Therefore, Raman and photoluminescence experiments strongly suggest charge transfer between the confined molecules and the nanotubes, leading to a Fermi level shift which governs the radiative de-excitation efficiency.

Synergistic effects of CdS QDs – Neutral red dye hybrid system on its nonlinear optical properties

One of the main goal in the area of nanophotonics is to reinforce the nonlinear optical effects at low input fluence. In this regard, nanohybrids have received special attention which render remarkable third-order nonlinear optical properties. Herein, we have studied the nonlinear optical properties of CdS Quantum Dots (QDs) - Neutral Red (NR) nanohybrid system using Z-scan technique and report the development of functional materials for optical limiting applications. Open aperture Z-scan results suggests that reverse saturable absorption is the predominant mechanism behind the observed nonlinear effects and it can be ascribed to enhanced triplet state population. A significant enhancement in the nonlinear absorption coefficient, nonlinear refraction and third-order nonlinear susceptibility is observed with the nanohybrids as compared to their individual components. The enhanced nonlinear properties can be attributed to cumulative effects of distinct nonlinear mechanisms.

Titanate-PMMA composites in photoluminescence based oxygen sensing

Titanate MTiO3 (M = Ni, Co) composites have been investigated for the first time as optical sensing materials. The photoluminescence (PL) emission of MTiO3 nano-hybrid systems, consisting of nanorods dispersed in an organic (poly (methyl methacrylate)-PMMA) matrix exhibited a reversible modification in the presence of oxygen (O2). For the optical characterization and study of the photoluminescence, the MTiO3/PMMA specimens were excited with a pulsed laser source of 248 nm wavelength.The performance of this new optical sensing system has been systematically investigated with respect to response, reversibility, and dynamic characteristics. All experimental results confirmed that the photoluminescence emission of the MTiO3 nanocomposites is sensitive and directly related to the oxygen presence, at room temperature. The MTiO3 nanohybrids, subjected to successive low vacuum-oxygen cycles, exhibited a dynamic response towards different ranges of oxygen concentrations, with the limit of detection being about 1 mbar and 5 mbar for NiTiO3 and CoTiO3 respectively and response time of the order of 40s.

Morphological and Chemical Analysis of Low-Density Polyethylene Crystallized on Carbon and Clay Nanofillers.

Interest in carbon and clay-based nanofillers has grown in recent years. The crystallization behavior of low-density polyethylene (LDPE) was studied using a variety of notable nanofillers used in engineering applications and prepared using a solution crystallization method. Carbon nanotubes (CNTs), graphene oxide nano-platelets, clay (montmorillonite), and modified clay (surface-modified with trimethyl stearyl ammonium) were used to induce heterogeneous crystallization of LDPE. The crystallized LDPE samples, imaged using scanning and transmission electron microscopy, revealed different microstructures for each nanohybrid system, indicating these various nanofillers induce LDPE lamellae ordering. The underlying interactions between polymer and nanofiller were investigated using FTIR spectroscopy. X-ray diffraction (XRD) was used to determine crystallinity. This work examines how the differences in morphology and chemical structure of the nanofillers induce changes in the nucleation and growth of polymer crystals. These results will provide guidance on functional design of nano-devices with controlled properties.

A Combined Antitumor Strategy Mediated by a New Targeted Nanosystem to Hepatocellular Carcinoma.

BackgroundHepatocellular carcinoma (HCC) is one of the main causes of cancer-related death. Sorafenib, which is the first-line therapy for this disease, is associated with reduced therapeutic efficacy that could potentially be overcome by combination with selumetinib. In this context, the main goal of this work was to develop a new nanosystem, composed of a polymeric core coated by a lipid bilayer containing the targeting ligand GalNAc, to specifically and efficiently co-deliver both drugs into HCC cells, in order to significantly increase their therapeutic efficacy.MethodsThe physicochemical characterization of hybrid nanosystems (HNP) and their components was performed by dynamic light scattering, zeta potential, matrix-assisted laser desorption ionization – time of flight mass spectroscopy, and transmission electron microscopy. Cellular binding, uptake and specificity of HNP were evaluated through flow cytometry and confocal microscopy. The therapeutic activity was evaluated namely through: cell viability by the Alamar Blue assay; cell death by flow cytometry using FITC-Annexin V; caspases activity by luminescence; mitochondrial membrane potential by flow cytometry; and molecular target levels by Western blot.ResultsThe obtained data show that these hybrid nanosystems present high stability and loading capacity of both drugs, and suitable physicochemical properties, namely in terms of size and surface charge. Moreover, the generated formulation allows to circumvent drug resistance and presents high specificity, promoting great cell death levels in HCC cells, but not in non-tumor cells. This potentiation of the antitumor effect of co-loaded drugs was carried out by an increased programmed cell death, being associated with a strong reduction in the mitochondrial membrane potential, a significant increase in the activity of caspases 3/7 and caspase 9, and much greater number of annexin V-positive cells.ConclusionThe developed formulation resulted in a high and synergistic antitumor effect, revealing a translational potential to improve therapeutic approaches against HCC.

Nanocomposite gels of poloxamine and Laponite for β-Lapachone release in anticancer therapy

Nano-hybrid systems have been shown to be an attractive platform for drug delivery. Laponite® RD (LAP), a biocompatible synthetic clay, has been exploited for its ability to establish of strong secondary interactions with guest compounds and hybridization with polymers or small molecules that improves, for instance, cell adhesion, proliferation, and differentiation or facilitates drug attachment to their surfaces through charge interaction. In this work, LAP was combined with Tetronics, X-shaped amphiphilic PPO-PEO (poly (propylene oxide)–poly (ethylene oxide) block copolymers. β-Lapachone (BLPC) was selected for its anticancer activity and its limited bioavailability due to very low aqueous solubility, with the aim to improve this by using LAP/Tetronic nano-hybrid systems. The nanocarriers were prepared over a range of Tetronic 1304 concentrations (1 to 20% w/w) and LAP (0 to 3% w/w). A combination of physicochemical methods was employed to characterize the hybrid systems, including rheology, particle size and shape (DLS, TEM), thermal analysis (TG and DSC), FTIR, solubility studies and drug release experiments. In vitro cytotoxicity assays were performed with BALB/3T3 and MCF-7 cell lines. In hybrid systems, a sol-gel transition can occur below physiological temperature. BLPC exhibits the most significant increase in solubility in formulations with a high concentration of T1304 (over 10% w/w) and 1.5% w/w LAP, or systems with only LAP (1.5%), with a 50 and 100-fold increase in solubilisation, respectively. TEM images showed spherical micelles of T1304, which elongated into wormlike micelles with concentration (20%) and in the presence of LAP, a finding that has not been reported before. A sustained release of BLPC over 140 hours was achieved in one of the formulations (10% T1304 with 1.5% laponite), which also showed the best selectivity index towards cancer cells (MCF-7) over BALB/3T3 cell lines. In conclusion, BLPC-loaded T1304/LAP nano-hybrid systems proved safe and highly effective and are thus a promising formulation for anticancer therapy.

Fabrication of gold nanostructure decorated polystyrene hybrid nanosystems via poly(L-DOPA) and their applications in surface-enhanced Raman Spectroscopy (SERS), and catalytic activity

Noble metallic nanostructure decorated-polymer hybrid systems provide certain advantages and represent remarkable performances in many applications including surface-enhanced Raman spectroscopy (SERS), catalysis, and biosensing. However, despite numerous attempts to fabricate these hybrid platforms, novel, simple, low-cost, reducing agent-free, and easy-to-follow procedures with significantly well-controlled over the desired nanostructure size are still highly required to prepare these efficient nanosystems. In this study, we propose the fabrication of the gold nanostructure decorated polystyrene (PS) nanospheres (NSs) via the polymer of 3,4-dihydroxyphenyl-L-alanine (PLDOPA). For the fabrication of PLDOPA coated PS NSs (PS@PLDOPA), a conformal thin film of PLDOPA was deposited onto the PS NSs by oxidative polymerization. The size, morphology, and interparticle distance of gold nanostructure decorated PS@PLDOPA colloidal composite system (PS@PLDOPA@Au NP) was manipulated by simply tuning the amount of the gold ions. The optimized PS@PLDOPA@Au NP systems showed extraordinary characteristics in SERS with an enhancement factor of 4.3 × 105 and catalytic activity in the total conversion of 4-nitrophenol within 5 min

Graphene-Based Magnetic Nanoparticles for Theranostics: An Overview for Their Potential in Clinical Application.

The combination of diagnostics and therapy (theranostic) is one of the most complex, yet promising strategies envisioned for nanoengineered multifunctional systems in nanomedicine. From the various multimodal nanosystems proposed, a number of works have established the potential of Graphene-based Magnetic Nanoparticles (GbMNPs) as theranostic platforms. This magnetic nanosystem combines the excellent magnetic performance of magnetic nanoparticles with the unique properties of graphene-based materials, such as large surface area for functionalization, high charge carrier mobility and high chemical and thermal stability. This hybrid nanosystems aims toward a synergistic theranostic effect. Here, we focus on the most recent developments in GbMNPs for theranostic applications. Particular attention is given to the synergistic effect of these composites, as well as to the limitations and possible future directions towards a potential clinical application.

RETRACTED: Ultrahigh resolution two-dimensional atomic localization via tunable surface plasmon polaritons

This article has been retracted: please see Elsevier Policy on Article Withdrawal ( https://www.elsevier.com/about/our-business/policies/article-withdrawal ). This article has been retracted at the request of Authors We are retracting this Article because the result is wrong for the following two crucial reasons. This article considered a nanohybrid system consisted of a core of atomic medium with dielectric constant e1 and an outer Ag metallic nanoparticle (MNP) shell with dielectric constant e2. Such nano-structures make the light fields inside the nanohybrid system highly inhomogeneous. It is impossible for the controlling fields to form the strong standing waves in such spherical shell nanostructures. Thus the Equation (1) of the modelling for the driving laser field with Rabi frequency Wc(x,y) inside the NMP shell is not valid. Furthermore, the modes inside such spherical structures are usually the well-known whispering gallery modes. The surface plasmonic dispersion relation given in (12), which is usually used for a plane interface, is not applicable in the spherical nanohybrid system. Since these two equations (1) and (12) are fundamentally wrong, we think that all results based on them are incorrect. Therefore all authors wish to retract this Article. We deeply regret for the inconvenience caused to Optics and Laser Technology and apologize to the scientific community.

Towards the development of antioxidant-wrapped graphene-based fluorescent nanomaterials having theranostic potentials: A combined experimental and theoretical study

We report here an easily implementable, economic and eco-friendly synthetic protocol for the antioxidant (DMAHF/DHF, 3-hydroxyflavone analogs)-wrapped fluorescent graphene oxide (GO). The antioxidant activity of DMAHF was further exploited to reduce GO; whereby DMAHF was oxidized. The mechanistic pathway of this rGO (reduced GO)-synthesis and its consequence on the fate of DMAHF; as well as the origin of spectral behavior of GO/rGO nanohybrid systems were understood by quantum chemical calculations and molecular docking studies. The GO/rGO-surface anchored (non-covalently) fluorescent antioxidant molecules (either in their native/oxidized forms) imposed characteristic fluorophoric nature to these nanohybrid systems. However, such interactions instigated a simultaneous quenching of the fluorescence of these molecules to some extent. Interestingly, the fluorescence of these nanohybrid systems was found to be largely enhanced in the presence of the biomolecules, like dsDNA (ctDNA). This was the basis of their activity as fluoroprobes for dsDNA. Being loaded with the bio-friendly antioxidant molecules, these nanohybrids can be potentially biocompatible. Thus, these graphene based nanohybrids with dsDNA-fluoroprobing efficacy and significant structural advantages can be promising candidates for the future development of advanced theranostic tools.