Organic-inorganic Nanostructures Research Articles

Fabrication and Characterization of Silver Nanoparticle-Doped Chitosan/Carboxymethyl Cellulose Nanocomposites for Optoelectronic and Biological Applications.

The synthesis of nanoparticles using environmentally friendly methods for applications in fields such as food packaging and biomedicine has been gaining increasing attention. Organic-inorganic nanostructures offer opportunities to create innovative materials suitable for use in optoelectronics and biological applications. In this study, we focused on producing nanocomposite films by blending carboxymethyl cellulose (CMC) and chitosan (CS) polymers in equal proportions (50/50 wt %) and adding silver nanoparticles (Ag NPs) through a solution casting process. Our objective was to examine how the introduction of Ag NPs influenced the structural, optical, mechanical, electrical, and antibacterial properties of the virgin CMC/CS composites. XRD patterns of the prepared samples indicated the presence of crystalline Ag phases within the CMC/CS blend. FT-IR spectroscopy showed the primary vibrational peaks associated with CMC and CS, which exhibited reduced intensity after the addition of Ag NPs. The UV absorption of the nanocomposites exhibited a gradual increase and a shift toward longer wavelengths. The electrical properties are enhanced with higher concentrations of Ag NPs. An increase in the content of Ag NPs resulted in a corresponding enhancement of antibacterial activity against both Staphylococcus aureus and Escherichia coli. The CMC/CS-Ag-doped films demonstrated significant enhancements in Young's modulus (Y), tensile stress (σt), and elongation at break (εB). These findings suggest that these nanocomposite films hold promise for potential applications in optoelectronics and biological fields.

Interfacial interaction promoted titanium oxide-based organic-inorganic nanoheterojunctions by chiral host-guest binding

Although titanium oxide (TiO2)-based organic-inorganic nanostructures attract increasing attention in energy fields, accurate regulation of close contact between TiO2 and organic components in nanostructures that determines their performance is still a critical task. Here, the interfacial interaction in TiO2-based organic-inorganic nanoheterojunctions is promoted by host-guest interactions, which are obtained through chiral recognition between chirality imprinted TiO2 and chiral organic molecules (L-PheAD), leading to their close contact. This close contact is due to the matching structure obtained from a multi-level chirality transfer between TiO2 and L-PheAD during molecular imprinting, facilitating the strong electronic coupling and resulting in a positive correlation between chiral signal intensity and the interface bonding strength in the nanoheterojunction. The tightly packed interface is further confirmed by the enhanced photocatalytic activity of TiO2-L-PheAD nanoheterojunctions. This work creates an opportunity to tailor the intimate contact between organic-inorganic interfaces based on host-guest systems with matched chiral space.

Development of Organic–Inorganic Nanostructure Labels for Food-Poisoning Bacteria

Development of Organic–Inorganic Nanostructure Labels for Food-Poisoning Bacteria

Recombinant Collagen-Templated Biomineralized Synthesis of Biocompatible pH-Responsive Porous Calcium Carbonate Nanospheres.

The synthesis of calcium carbonate with controlled morphology is crucial for its biomedical applications. In this study, we synthesized well-ordered porous calcium carbonate nanospheres using recombinant collagen as a biomineralization template. Porous collagen-calcium carbonate was created by incubating calcium chloride and sodium carbonate with collagen biotemplates at room temperature. Our results show that the recombinant collagen-calcium carbonate nanomaterials underwent a morphological transition from solid nanospheres to more porous nanospheres and a phase transformation from vaterite to a mixture of calcite and vaterite. This study highlights the crucial role of recombinant collagen in modulating the morphology and crystallinity of calcium carbonate nanoparticles. Importantly, the highly porous recombinant collagen-calcium carbonate hybrid nanospheres demonstrated superior loading efficacy for the model drug cefoperazone. Furthermore, the drug loading and releasing results suggest that hybrid nanospheres have the potential to be robust and biocompatible pH-responsive drug carriers. Our findings suggest that recombinant collagen's unique amino acid content and rodlike structure make it a superior template for biomineralized synthesis. This study provides a promising avenue for the production of novel organic-inorganic nanostructures, with potential applications in biomedical fields such as drug delivery.

Photon Upconversion in the Visible Wavelengths with ZnSe/InP/ZnS Nanocrystals

Nanocrystals that can absorb strongly in the near-infrared (NIR) wavelengths for conversion to visible light are of great interest for biological imaging applications. In this work, we examine an inverse Type-I heterostructure with an inner InP shell for triplet–triplet annihilation-based photon upconversion. The InP-based nanocrystals are earth-abundant, benign, and can be synthetically tuned to absorb in the entire NIR window I. Here, a two monolayer ZnS shell was used to passivate the surface defects on inverse Type-I ZnSe/InP core/shell particles. We show that this ZnS shell increases the InP photoluminescence quantum yield (QY) by a factor of 16 to 0.43 and the transmitter triplet lifetime from 138 to 451 μs, but decreases the rate of triplet energy transfer by a factor of 3. This results in the ZnSe/InP and ZnSe/InP/ZnS nanocrystal triplet photosensitizers producing a similar photon upconversion QY of about 4.0% (out of a maximum of 50%) when paired with 9,10-diphenylanthracene as the blue emitter. This work suggests that the ZnS shell can be further tuned to increase the photon upconversion QY. This work also shows that ZnSe/InP/ZnS nanocrystals are promising candidates for a hybrid organic–inorganic nanostructure that can convert NIR photons to visible light.

Synthesis of Novel Polymer-Assisted Organic-Inorganic Hybrid Nanoflowers and Their Application in Cascade Biocatalysis.

This study reports on the synthesis of novel bienzyme polymer-assisted nanoflower complexes (PANF), their morphological and structural characterization, and their effectiveness as cascade biocatalysts. First, highly porous polyamide 6 microparticles (PA6 MP) are synthesized by activated anionic polymerization in solution. Second, the PA6 MP are used as carriers for hybrid bienzyme assemblies comprising glucose oxidase (GOx) and horseradish peroxidase (HRP). Thus, four PANF complexes with different co-localization and compartmentalization of the two enzymes are prepared. In samples NF GH/PA and NF GH@PA, both enzymes are localized within the same hybrid flowerlike organic-inorganic nanostructures (NF), the difference being in the way the PA6 MP are assembled with NF. In samples NF G/PAiH and NF G@PAiH, only GOx is located in the NF, while HRP is preliminary immobilized on PA6 MP. The morphology and the structure of the four PANF complexes have been studied by microscopy, spectroscopy, and synchrotron X-ray techniques. The catalytic activity of the four PANF was assessed by a two-step cascade reaction of glucose oxidation. The PANF complexes are up to 2-3 times more active than the free GOx/HRP dyad. They also display enhanced kinetic parameters, superior thermal stability in the 40-60 °C range, optimum performance at pH 4-6, and excellent storage stability. All PANF complexes are active for up to 6 consecutive operational cycles.

Bioengineered Carboxymethylcellulose-Peptide Hybrid Nanozyme Cascade for Targeted Intracellular Biocatalytic-Magnetothermal Therapy of Brain Cancer Cells.

Glioblastoma remains the most lethal form of brain cancer, where hybrid nanomaterials biofunctionalized with polysaccharide peptides offer disruptive strategies relying on passive/active targeting and multimodal therapy for killing cancer cells. Thus, in this research, we report for the first time the rational design and synthesis of novel hybrid colloidal nanostructures composed of gold nanoparticles stabilized by trisodium citrate (AuNP@TSC) as the oxidase-like nanozyme, coupled with cobalt-doped superparamagnetic iron oxide nanoparticles stabilized by carboxymethylcellulose ligands (Co-MION@CMC) as the peroxidase-like nanozyme. They formed inorganic–inorganic dual-nanozyme systems functionalized by a carboxymethylcellulose biopolymer organic shell, which can trigger a biocatalytic cascade reaction in the cancer tumor microenvironment for the combination of magnetothermal–chemodynamic therapy. These nanoassemblies were produced through a green aqueous process under mild conditions and chemically biofunctionalized with integrin-targeting peptide (iRDG), creating bioengineered nanocarriers. The results demonstrated that the oxidase-like nanozyme (AuNP) was produced with a crystalline face-centered cubic nanostructure, spherical morphology (diameter = 16 ± 3 nm), zeta potential (ZP) of −50 ± 5 mV, and hydrodynamic diameter (DH) of 15 ± 1 nm. The peroxide-like nanostructure (POD, Co-MION@CMC) contained an inorganic crystalline core of magnetite and had a uniform spherical shape (2R = 7 ± 1 nm) which, summed to the contribution of the CMC shell, rendered a hydrodynamic diameter of 45 ± 4 nm and a negative surface charge (ZP = −41 ± 5 mV). Upon coupling both nanozymes, water-dispersible colloidal supramolecular vesicle-like organic–inorganic nanostructures were produced (AuNP//Co-MION@CMC, ZP = −45 ± 4 mV and DH = 28 ± 3 nm). They confirmed dual-nanozyme cascade biocatalytic activity targeted by polymer–peptide conjugates (AuNP//Co-MION@CMC_iRGD, ZP = −29 ± 3 mV and DH = 60 ± 4 nm) to kill brain cancer cells (i.e., bioenergy “starvation” by glucose deprivation and oxidative stress through reactive oxygen species generation), which was boosted by the magneto-hyperthermotherapy effect when submitted to the alternating magnetic field (i.e., induced local thermal stress by “nanoheaters”). This groundwork offers a wide avenue of opportunities to develop innovative theranostic nanoplatforms with multiple integrated functionalities for fighting cancer and reducing the harsh side effects of conventional chemotherapy.

A universal concept for area‐selective assembly of metal oxide core‐shell nanoparticles, nanorods, and organic molecules via amide coupling reactions

AbstractThe deposition of nanomaterials (NMs) on substrate is a pertinent for a variety of applications in nanometer‐sized electronics, mechanics, or catalysis. This paper establishes a universal and simple approach for assembly of functionalized metal oxide core nanoparticles (NPs) and nanorods (NRs) on a substrate with uniformity, area‐selectivity, and full order control. Particularly, the aluminium oxide (AlOx) NPs, titanium dioxide (TiO2) NRs, and TiO2 NPs functionalized by self‐assembled monolayer (SAM) molecules are deposited on substrate alternatively layer‐by‐layer. This assembling is performed in solution on the pre‐patterned surface with SAM molecules via amide coupling reactions in order to achieve the reaction‐orthogonality. Moreover, this stacking of inorganic NPs/NRs in a terminated implementation is progressed into latter layer of TiO2 NPs functionalized by 1‐aminopyrene molecules representing an example of hybrid organic‐inorganic formation with fluorescence emission. The deposited layers are characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and total internal reflection fluorescence microscope (TIRFM). The significant versatility of stacked metal oxide core‐shell NPs/NRs via based‐solution method represents excellent and efficient applicability in manufacture of hybrid organic–inorganic nanostructure.

Glucose-Sensing Photonic Nanochain Probes with Color Change in Seconds.

Glucose‐sensing photonic crystals are promising for the significant advance of continuous glucose monitoring systems due to the naked‐eye colorimetric readouts and noninvasive detection of diabetes, but the long response time hampers their practical applications. Here, for the first time probes of photonic nanochains (PNCs) are demonstrated that are capable of continuously and reversibly sensing glucose concentration ([glucose]) variation within seconds by color change without power consumption, much faster by 2–3 orders of magnitude than previous ones. They are comprised of 1D equidistant arrays of magnetic nanoparticles enveloped by tens‐of‐nanometer‐thick phenylboronic acid‐functionalized hydrogels, and fabricated by developing selective concentration polymerization of monomers in binary microheterogeneous solvents of dimethyl sulfoxide (DMSO) and H2O. In this process, both 3‐acrylamido phenylboronic acid (AAPBA) and N‐2‐hydroxyethyl acrylamide (HEAAm) are preferentially dissolved in the small volume of free DMSO concentrated in the vicinity of poly vinylpyrrolidone coated Fe3O4 colloidal nanoparticles (Fe3O4@PVP), yielding Fe3O4@PVP@poly(AAPBA‐co‐HEAAm) PNCs after UV irradiation under magnetic field. The PNCs in phosphate buffered solution have a wavelength‐shift range up to 130 nm when [glucose] changes from 0 to 20 × 10−3 m. The results can facilitate real‐time glucose monitoring and provide an alternative to produce functional organic–inorganic nanostructures.

Porphyrin Functionalization of CsPbBrI2/SiO2 Core–Shell Nanocrystals Enhances the Stability and Efficiency in Electroluminescent Devices

AbstractSurface ligand exchange on all‐inorganic perovskite nanocrystals of composition CsPbBrI2 reveals improved optoelectronic properties due to strong interactions of the nanocrystal with mono‐functionalized porphyrin derivatives. The interaction is verified experimentally with an array of spectroscopic measurements as well as computationally by exploiting density functional theory calculations. The enhanced current efficiency is attributed to a lowering of the charging energy by a factor of 2–3, which is determined by combining electronic and optical measurements on a selection of ligands. The coupled organic–inorganic nanostructures are successfully deployed in a light‐emitting device with higher current efficacy and improved charge carrier balance, magnifying the efficiency almost fivefold compared to the native ligand.

Strong coupling effects in a plexciton system of gold nanostars and J-aggregates

Strong exciton–plasmon interaction enables effective control of the photonic properties of hybrid organic–inorganic nanostructures encompassing light absorption, scattering and luminescence. Whereas the manifestations of light-matter interactions in the absorption and scattering are reasonably well understood their relation to the luminescence as well as luminescence properties themselves in strongly coupled plexcitonic hybrids is still largely underexplored especially for a system with a complex mechanism of hybridisation of states. Here we report on investigation of the interaction between localized and hybridized plasmons in gold nanostars and excitons in J-aggregates under ambient conditions. Our findings demonstrate the quality performance of the formed plexciton system with multiple hybridization channels in terms of the parameters of strong coupling, such as Rabi splitting (230 meV), coupling-strength-to-transition energy ratio (0.07), and cooperativity (2.03). The results of time-resolved experiments elucidate the observed enhanced spontaneous emission rate with regard to the Purcell effect, whose value was estimated from the extinction spectra of the strongly coupled plexciton system.

Coupled Organic-Inorganic Nanostructures with Mixed Organic Linker Molecules.

The electronic properties of semiconducting inorganic lead sulfide (PbS) nanocrystals (NCs) and organic linker molecules are dependent on the size of NCs as well as the used ligands. Here, we demonstrate that a weakly binding ligand can be successfully attached to PbS NCs to form a coupled organic-inorganic nanostructure (COIN) by mixing with a strong binding partner. We use the weakly binding zinc β-tetraaminophthalocyanine (Zn4APc) in combination with the strongly binding 1,2-ethanedithiol (EDT) as a mixed ligand system and compare its structural, electronic, and (photo-)electrical properties with both single-ligand COINs. It is found that binding of Zn4APc is assisted by the presence of EDT leading to improved film homogeneity, lower trap density, and enhanced photocurrent of the derived devices. Thus, the mixing of ligands is a versatile tool to achieve COINs with improved performance.

Molecular Bottom-Up Approaches for the Synthesis of Inorganic and Hybrid Nanostructures

Chemical routes for the synthesis of nanostructures are fundamental in nanoscience. Among the different strategies for the production of nanostructures, this article reviews the fundamentals of the bottom-up approaches, focusing on wet chemistry synthesis. It offers a general view on the synthesis of different inorganic and hybrid organic–inorganic nanostructures such as ceramics, metal, and semiconductor nanoparticles, mesoporous structures, and metal–organic frameworks. This review article is especially written for a wide audience demanding a text focused on the basic concepts and ideas of the synthesis of inorganic and hybrid nanostructures. It is styled for both early researchers who are starting to work on this topic and also non-specialist readers with a basic background on chemistry. Updated references and texts that provide a deeper discussion and describing the different synthesis strategies in detail are given, as well as a section on the current perspectives and possible future evolution.

Polarization-Induced Quantum-Mechanical Charge Transfer in Perovskite–Graphene Nanocomposites with Superior Electro-optic Switching Modulation

Understanding the concept of light–matter interaction in organic–inorganic nanostructures such as graphene and metal-halide perovskites has been explored to realize photonic and optoelectronic devices. The strong light–matter interaction and impressive performance achieved by tuning the optical/electrical properties have enabled them as potential candidates for optoelectronic applications. In this perspective, we report the synthesis of metal-halide perovskite nanocomposites by incorporation of graphene sheets into the perovskite framework, which exhibits a significant enhancement in electro-optic (E-O) switching modulation. The carrier dynamics in the nanocomposite is investigated using time-resolved luminescence and broadband dielectric spectroscopy studies to get insights into the carrier relaxation and transfer mechanisms. The presence of graphene in the perovskite nanocomposites induced dielectric polarization with a strong electrical conduction and a nonlinear dielectric behavior with negative permittivity at the percolation threshold concentration because of the large resonance derived from the plasmonic oscillations of delocalized charges. A custom-designed optical fiber integrated with nanocomposites is scrutinized to explore the light modulation and E-O sensitivity under an applied electrical field. The E-O interference that leads to phase modulation of light by change in the refractive index of the graphene–CsPbBr3 nanocomposites resulted in a higher E-O sensitivity of 18 nm/V than those of CsPbBr3 nanostructures.

Prospects of Coupled Organic-Inorganic Nanostructures for Charge and Energy Transfer Applications.

We review the field of organic–inorganic nanocomposites with a focus on materials that exhibit a significant degree of electronic coupling across the hybrid interface. These nanocomposites undergo a variety of charge and energy transfer processes, enabling optoelectronic applications in devices which exploit singlet fission, triplet energy harvesting, photon upconversion or hot charge carrier transfer. We discuss the physical chemistry of the most common organic and inorganic components. Based on those we derive synthesis and assembly strategies and design criteria on material and device level with a focus on photovoltaics, spin memories or optical upconverters. We conclude that future research in the field should be directed towards an improved understanding of the binding motif and molecular orientation at the hybrid interface.

Preparation and characterization of a novel organic–inorganic hybrid nanostructure: application in synthesis of spirocompounds

Immobilization and heterogenization of acidic/basic groups or organic tags on inorganic supports have found many important applications in recent years. In this investigation, a new hybrid organic–inorganic nanostructure was prepared. The structure of novel nanomaterial was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, vibrating sample magnetometer, scanning electron microscopy and the energy-dispersive X-ray spectroscopy techniques. The spirocompounds, especially spiroperimidines and pyranopyrazoles, are important structures with diverse biological activities and many applications in industries. So, the prepared hybrid nanomaterial was used as an efficient catalyst in the one-pot, green and simple protocol for the synthesis of pyranopyrazole, spiropyranopyrazole and spiroperimidine derivatives. The structure of some compounds is characterized by FT-IR, 1H-NMR and 13C-NMR analyses. In addition, the proposed intermediates were synthesized and identified to prove the presented mechanism of the reaction. This hybrid nanomaterial is a recyclable and highly efficient heterogeneous catalyst and easily separated by an external magnet from the reaction media. The short reaction time, high efficiency, operational safety and use of environmentally benign solvent are some benefits of this procedure.

Single cell immunodetection of Escherichia coli O157:H7on an indium-tin-oxide electrode by using an electrochemical label with an organic-inorganic nanostructure.

A rapid and highly sensitive method is described for the detection of enterohemorrhagic Escherichia coli O157:H7. An organic-inorganic nanostructure in which numerous gold nanoparticles (AuNPs) are enclosed with polyaniline (PANI) was utilized as an electrochemical label. The nanostructure showed (a) strong light scattering intensity due to the coupling effect of the surface plasmon resonance based on the presence of AuNPs, and (b) high electrochemical response due to the redox activityof PANI. To achieve selectivity, antibody againstE. coli O157:H7 was immobilized on the surface of the nanostructure. The method exploits the combination of strong adsorption of bacterial cells onto the indium-tin-oxide (ITO) glass electrode without any special processing and specific binding of the nanostructuredlabel to E. coli O157:H7. This enables the electrochemical detection of a single cell on the ITO electrode. The electrochemical response to E. coli O157:H7 was 30-fold higher than that to other types of bacteria. This procedure can be applied to the determinationof E. coli O157:H7 even in the presence of other bacteria. Graphical abstract Schematic of a voltammetric immunoassay for Escherichia coli O157:H7 by using a nanocomposite consisting of gold nanoparticles and polyaniline on an ITO electrode.

Correlated, Dual-Beam Optical Gating in Coupled Organic-Inorganic Nanostructures.

An optical switch with two distinct resonances is formed by combining PbS nanocrystals and the conductive polymer poly[sodium 2-(2-ethynyl-4-methoxyphenoxy)acetate] (PAE) into a hybrid thin film. Infrared excitation of the nanocrystals invokes charge transfer and consecutive polaron formation in the PAE, which activates the switch for excited-state absorption at visible frequencies. The optical modulation of the photocurrent response of the switch exhibits highly wavelength-selective ON/OFF ratios. Transient absorption spectroscopy shows that the polaron formation is correlated with the excited state of the nanocrystals, opening up new perspectives for photonic data processing. Such correlated activated absorption can be exploited to enhance the sensitivity for one optical signal by a second light source of different frequency as part of an optical amplifier or a device with AND logic.

Correlated, Dual‐Beam Optical Gating in Coupled Organic–Inorganic Nanostructures

AbstractAn optical switch with two distinct resonances is formed by combining PbS nanocrystals and the conductive polymer poly[sodium 2‐(2‐ethynyl‐4‐methoxyphenoxy)acetate] (PAE) into a hybrid thin film. Infrared excitation of the nanocrystals invokes charge transfer and consecutive polaron formation in the PAE, which activates the switch for excited‐state absorption at visible frequencies. The optical modulation of the photocurrent response of the switch exhibits highly wavelength‐selective ON/OFF ratios. Transient absorption spectroscopy shows that the polaron formation is correlated with the excited state of the nanocrystals, opening up new perspectives for photonic data processing. Such correlated activated absorption can be exploited to enhance the sensitivity for one optical signal by a second light source of different frequency as part of an optical amplifier or a device with AND logic.

Electrochromic strategy for tungsten oxide/polypyrrole hybrid nanofiber materials

High-quality hybrid nanofibers were fabricated with the aim of studying their feasibility as electrochromic systems. Tungsten oxide/polypyrrole films were electrochemically synthesized into four different ionic liquids: 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4), 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide (BMIMTFSI), and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl) imide (BMPTFSI), followed by electrospinning deposition. The influence of ionic liquid on the morphology of formed hybrid nanofiber samples was observed by scanning electron microscopy (SEM) measurements. Energy dispersive X-ray spectroscopy (EDX) was also employed to confirm the compositions of nanofibers. Electrochromic devices fashioned from these hybrid nanofiber arrays were found to display remarkable electrochromic performance with reversible color change, fast optical modulation and superior cycling stability. These improvements can be attributed to the high porosity of the nanofibers, their larger accessible surface area and rational combination of two electrochemically active materials. PPy/WO3/BMIMPF6 based device showed marked enhancement of electrochromic contrast and coloration efficiency over other nanofiber based devices: the transmittance change of 47.41% along coloration efficiency of 329.45 cm2/C. These synergistic organic-inorganic nanostructures pave the way for forming new materials to be used in advanced applications.