Hybrid Nanocrystals Research Articles

Graphene-Metal Nanocrystal Hybrid Materials for Bioapplications.

The development of functional nanomaterials is crucial for advancing personalized and precision medicine. Graphene-metal nanocrystal hybrid materials not only possess the intrinsic advantages of graphene-based materials but also exhibit additional optical, magnetic, and catalytic properties of various metal nanocrystals, showing great synergies in bioapplications, including biosensing, bioimaging, and disease treatments. In this Perspective, we discuss the advantages and design principles of graphene-metal nanocrystal hybrid materials and provide an overview of their applications in biological fields. Finally, we highlight the challenges and future directions for their practical implementation.

The selective proapoptotic impact of the myricetin-loaded alginate-cellulose hybrid nanocrystals (MAC-NCs) on the human AGS gastric cancer cells.

Myricetin, a flavanol present in fruits, tea, and vegetables, has the potential to reduce chronic diseases like gastric cancer by promoting cell death and stopping cell growth. However, its limited bioactivity due to its short lifespan and poor solubility in water has been a challenge. The current research focuses on incorporating myricetin into alginate-cellulose hybrid nanocrystals to enhance its selective proapoptotic effects on human AGS gastric cancer cells. MAC-NCs, myricetin-loaded alginate-cellulose hybrid nanocrystals, were synthesized using a combined co-precipitation/ultrasonic homogenization method and characterized through Dynamic Light Scattering (DLS), Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscope (FESEM), and Zeta-potential analyses. Their cytotoxic activity was tested on cancerous (AGS) and normal (Huvec) cells, revealing selective toxicity. Apoptotic markers, Caspase 8 and Caspase 9, gene expression was measured, and cell death type was confirmed using DAPI staining and flow cytometry on AGS cells. Synthesized MAC-NCs, measuring 40nm, showed significant selective toxicity on human gastric cells (IC50 of 31.05µg/mL) compared to normal endothelial cells (IC50 of 214.26µg/mL). DAPI and annexin flow cytometry revealed increased apoptotic bodies in gastric cells, indicating apoptosis. However, the apoptosis was found to be independent of Caspase-8 and Caspase-9. The current study provides critical insights into the therapeutic potential of MAC-NCs for gastric cancer treatment. Based on the notable induction of apoptosis in the AGS cancer cell line, the synthesized MAC-NCs exhibit promising potential as a selective anti-gastric cancer agent. However, further in-vivo studies are necessary to confirm and quantify the nanoparticle's selective toxicity and pharmaceutical properties in future investigations.

Seeded Growth of AuPt-PdAg Solid–Hollow Hybrid Nanocrystals and Their Applications in Plasmon-Enhanced Catalysis

Seeded Growth of AuPt-PdAg Solid–Hollow Hybrid Nanocrystals and Their Applications in Plasmon-Enhanced Catalysis

Tunable Emissive CsPbBr3/Cs4PbBr6 Quantum Dots Engineered by Discrete Phase Transformation for Enhanced Photogating in Field-Effect Phototransistors.

Precise control of quantum structures in hybrid nanocrystals requires advancements in scientific methodologies. Here, on the design of tunable CsPbBr3/Cs4PbBr6 quantum dots are reported by developing a unique discrete phase transformation approach in Cs4PbBr6 nanocrystals. Unlike conventional hybrid systems that emit solely in the green region, this current strategy produces adjustable luminescence in the blue (450nm), cyan (480nm), and green (510nm) regions with high photoluminescence quantum yields up to 45%, 60%, and 85%, respectively. Concentration-dependent studies reveal that phase transformation mechanisms and the factors that drive CsBr removal occur at lower dilutions while the dissolution-recrystallization process dominates at higher dilutions. When the polymer-CsPbBr3/Cs4PbBr6 integrated into a field-effected transistor the resulting phototransistors featured enhanced photosensitivity exceeding 105, being the highest reported for an n-type phototransistor, while maintaining good transistor performances as compared to devices consisting of polymer-CsPbBr3 NCs.

Construction of A-FeOx/LaFeO3 hybrid microreactors for efficient photocatalytic degradation of organic pollutants

Low-dimensional hybrid nanocrystals are newly emerging active photocatalysts for separating electron-hole pairs, but the instability and low quantum efficiency caused by particle aggregation and hybrid structure relaxation remain great challenges. To this end, herein we constructed amorphous FeOx (A-FeOx) and crystalline LaFeO3 hybrids by a sol-gel method. The amorphous-crystalline hybrids, A-FeOx/LaFeO3, not only improve the surface area and alter the band position, but also form numerous channels that are conducive to the transport of electrons and separation of electron–hole pairs, acting as microreactors. Photocatalytic tests show that the A-FeOx/LaFeO3 is highly active for the degradation of various organic pollutants, with reaction rate constant of 1.19 × 10–2 min–1 for ciprofloxacin degradation, for example, which is 1.82 and 1.87 times higher than that of LaFeO3 and Fe2O3/LaFeO3, respectively, owing to the formation of microreactors between A-FeOx and LaFeO3. Cycling tests show that the material has good stability in the reaction, and trapping experiments demonstrate that the photo-induced holes are the main reactive species of the reaction. This work provides a novel and feasible insight into the design of high performance low-dimensional hybrid nanocatalysts for photocatalysis.

Obtaining Ligand-Free Aqueous Au-Nanoparticles Using Reversible CsPbBr3 ↔ Au@CsPbBr3 Nanocrystal Transformation.

Water-hexane interfacial preparation of photostable Au@CsPbBr3 (Au@CPB) hybrid nanocrystals (NCs) from pure CsPbBr3 (CPB) NCs is reported, with the coexistence of exciton and localized surface plasmon resonance with equal dominance. This enables strong exciton-plasmon coupling in these plasmonic perovskite NCs where not only the photoluminescence is quenched intrinsically due to ultrafast charge separation, but also the light absorption property increases significantly, covering the entire visible region. Using a controlled interfacial strategy, a reversible chemical transformation between CPB and Au@CPB NCs is shown, with the simultaneous eruption of larger-size ligand-free aqueous Au nanoparticles (NPs). An adsorption-desorption mechanism is proposed for the reversible transformation, while the overgrowth reaction of the Au NPs passes through the Au aggregation intermediate. This study further shows that the plasmonic Au@CPB hybrid NCs as well as ligand-free Au NPs exhibit clear surface enhanced Raman scattering (SERS) effect of a commercially available probe molecule. Overall, the beautiful interfacial chemistry delivers two independent plasmonic materials, i.e., Au@CPB NCs and ligand-free aqueous Au NPs, which may find important implications in photocatalytic and biomedical applications.

Immobilization of Thermoplasma acidophilum Glucose Dehydrogenase and Isocitrate Dehydrogenase Through Enzyme-Inorganic Hybrid Nanocrystal Formation

The development of green catalysts, specifically biocatalysts, is crucial for building a sustainable society. To enhance the versatility of biocatalysts, the immobilization of enzymes plays a vital role as it improves their recyclability and robustness. As target enzymes to immobilize, glucose dehydrogenases and carboxylases are particularly important among various kinds of enzymes due to their involvement in two significant reactions: regeneration of the reduced form of coenzyme required for various reactions, and carboxylation reactions utilizing CO2 as a substrate, respectively. In this study, we immobilized Thermoplasma acidophilum glucose dehydrogenase (TaGDH) and T. acidophilum isocitrate dehydrogenase (TaIDH) using a previously reported method involving the formation of enzyme-inorganic hybrid nanocrystals, in the course of our continuing study focusing on carboxylation catalyzed by the free form of TaGDH and TaIDH. Subsequently, we investigated the properties of the resulting immobilized enzymes. Our results indicate the successful immobilization of TaGDH and TaIDH through the formation of hybrid nanocrystals utilizing Mn2+. The immobilization process enhanced TaIDH activity, up to 211%, while TaGDH retained 71% of its original activity. Notably, the immobilized TaGDH exhibited higher activity at temperatures exceeding 87 °C than the free TaGDH. Moreover, these immobilized enzymes could be recycled. Finally, we successfully utilized the immobilized enzymes for the carboxylation of 2-ketoglutaric acid under 1 MPa CO2. In conclusion, this study represents the first immobilization of TaGDH and TaIDH using the hybrid nanocrystal forming method. Furthermore, we achieved significant activity enhancement of TaIDH through immobilization and demonstrated the recyclability of the immobilized enzymes.

A novel multi-drugs ciprofloxacin-curcumin-N-acetylcysteine co-delivery system based on hybrid nanocrystals for dry powder inhalations

This study designed a novel multi-drugs co-delivery system of ciprofloxacin-curcumin-N-acetylcysteine based on hybrid nanocrystals technology for dry powder inhalations (DPIs). The particle size of PVP k-30 stabilized curcumin nanosuspensions and Poloxamer 188 stabilized ciprofloxacin - N-acetylcysteine (NAC) hybrid nanocrystals was 219.2±4.6 nm and 346.3±7.3 nm, respectively (n=3). The curcumin nanosuspensions was solidified with ciprofloxacin - N-acetylcysteine (NAC) hybrid nanocrystals accompanied by the L-leucine to improve the dispersion of the DPIs. The dispersion, uniformity and fluidity of the spray-dried ciprofloxacin - N-acetylcysteine - curcumin (CPFX/NAC/Cur) nanosuspensions superior to the freeze-dried DPIs. The ciprofloxacin and curcumin of the CPFX/NAC/Cur DPIs obtained by spray-drying with mannitol was amorphous form, and thereby the dispersibility and solubility would be further improved. The four components complex DPIs delivery system designed in this study could give full play to the effects of each component, and then produce synergistic results. Therefore, this multi-drugs ciprofloxacin-curcumin-N-acetylcysteine co-delivery system based on hybrid nanocrystals has the potential to be used in the clinical treatment of pulmonary infections to improve the treatment effect and quality of life of patients.

Advanced lead-free double perovskites/silica hybrid nanocrystals for highly stable light-emitting diodes

Cs2AgIn0.98Bi0.02Cl6@KIT-6 NCs were obtained by in situ assembly within KIT-6 mesoporous molecular sieves, and their fluorescence thermal stability was significantly improved benefiting from the protection of the KIT-6 shell layer.

Silicon nanocrystal hybrid photocatalysts as models to understand solar fuels producing assemblies

A rhenium metal complex tethered to a silicon quantum dot allows exploration of the effects of catalyst anchoring and Re–Si energetic alignment on photocatalytic CO2 reduction activity.

Nano-Bricks Assembly Toward 1D Metal Oxide Nanorods.

The rational design of hybrid nanocrystals structures facilitates electronic and energetic communication between different component, which can optimize their specific performance. In this study, an efficient approach for building intricate ZnO@h-CoO nanocomposites and their derivatives is presented, based on a lattice-match/mismatch mechanism. Due to the ultra-low lattice mismatch between ZnO and hexagonal CoO (as low as 0.18%), the h-CoO layer enables epitaxial growth on the ZnO templates, and ZnO can also grow epitaxially outside the CoO layer with ease. Similarly, the thickness of the epitaxial layer and the number of alternating layers can be adjusted arbitrarily. In contrast to h-CoO, the growth of cubic crystalline oxides (such as MnO) on ZnO results in the formation of nanoparticles due to a large mismatch index (following the Volmer-Weber models). Interestingly, when h-CoO is introduced as a further component into the MnO/ZnO composite, the cubic crystalline particles on the surface of the ZnO do not disturb the epitaxial growth of the h-CoO, allowing for the formation of nanocomposites with more components. Furthermore, additional units can be added to the nanocomposite further based on the lattice-match/mismatch mechanism, which is analogous to the building nano-bricks.

Hybridization of cellulose nanocrystals modified ZnO nanoparticles with bio-based hyperbranched waterborne polyurethane sizing agent for superior UV resistance and interfacial properties of CF/PA6 composites

The interface of carbon fiber (CF) reinforced composites has been a long challenging issue that restricts the full utilization of its excellent properties in industrial applications. In present work, a green solvent γ-valerolactone and biogenetic derived gallic acid and tartaric acid were used to prepare a hyperbranched waterborne polyurethane (HWPU) sizing agent. Meanwhile, cellulose nanocrystal modified zinc oxide (CNC–ZnO) nanohybrids were successfully synthesized using a facile one-pot method to improve the dispersibility and specific surface area of ZnO nanoparticles. The hybridization of CNC–ZnO substantially enhanced the thermostability and UV resistance of bio-based HWPU. The mechanical properties of the modified composites were thoroughly examined, revealing remarkable enhancements in flexural strength and interlaminar shear strength, with improvements of 46.5 % and 48.1 % compared to pristine CF. Additionally, the interfacial shear strength test demonstrated a significant increase of 63.6 %. Remarkably, the modified carbon fiber composites retained more than 97 % of their mechanical properties after being subjected to continuous xenon irradiation for a week, highlighting the exceptional ultroviolet resistance derived from the hybrid HWPU sizing agent.

Tailoring piezoresistive response of carbon nanotubes sensors by hybridization of cellulose nanocrystals for composite structures

Tailoring piezoresistive response of carbon nanotubes sensors by hybridization of cellulose nanocrystals for composite structures

Type-I CdSe@CdS@ZnS Heterostructured Nanocrystals with Long Fluorescence Lifetime.

Conventional single-component quantum dots (QDs) suffer from low recombination rates of photogenerated electrons and holes, which hinders their ability to meet the requirements for LED and laser applications. Therefore, it is urgent to design multicomponent heterojunction nanocrystals with these properties. Herein, we used CdSe quantum dot nanocrystals as a typical model, which were synthesized by means of a colloidal chemistry method at high temperatures. Then, CdS with a wide band gap was used to encapsulate the CdSe QDs, forming a CdSe@CdS core@shell heterojunction. Finally, the CdSe@CdS core@shell was modified through the growth of the ZnS shell to obtain CdSe@CdS@ZnS heterojunction nanocrystal hybrids. The morphologies, phases, structures and performance characteristics of CdSe@CdS@ZnS were evaluated using various analytical techniques, including transmission electron microscopy, X-ray diffraction, UV-vis absorption spectroscopy, fluorescence spectroscopy and time-resolved transient photoluminescence spectroscopy. The results show that the energy band structure is transformed from type II to type I after the ZnS growth. The photoluminescence lifetime increases from 41.4 ns to 88.8 ns and the photoluminescence quantum efficiency reaches 17.05% compared with that of pristine CdSe QDs. This paper provides a fundamental study and a new route for studying light-emitting devices and biological imaging based on multicomponent QDs.

Type-I CdS/ZnS Core/Shell Quantum Dot-Gold Heterostructural Nanocrystals for Enhanced Photocatalytic Hydrogen Generation.

Developing Type-I core/shell quantum dots is of great importance toward fabricating stable and sustainable photocatalysts. However, the application of Type-I systems has been limited due to the strongly confined photogenerated charges by the energy barrier originating from the wide-bandgap shell material. In this project, we found that through the decoration of Au satellite-type domains on the surface of Type-I CdS/ZnS core/shell quantum dots, such an energy barrier can be effectively overcome and an over 400-fold enhancement of photocatalytic H2 evolution rate was achieved compared to bare CdS/ZnS quantum dots. Transient absorption spectroscopic studies indicated that the charges can be effectively extracted and subsequently transferred to surrounding molecular substrates in a subpicosecond time scale in such hybrid nanocrystals. Based on density functional theory calculations, the ultrafast charge separation rates were ascribed to the formation of intermediate Au2S layer at the semiconductor-metal interface, which can successfully offset the energy confinement introduced by the ZnS shell. Our findings not only provide insightful understandings on charge carrier dynamics in semiconductor-metal heterostructural materials but also pave the way for the future design of quantum dot-based hybrid photocatalytic systems.

SnO2:TiO2 hybrid nanocrystals as electron transport layer for high-efficiency and stable planar perovskite solar cells

SnO2:TiO2 hybrid nanocrystals as electron transport layer for high-efficiency and stable planar perovskite solar cells

Biomimetic mineralization by confined diffusion with viscous hyaluronan network: Assembly of hierarchical flower-like supraparticles

Biomolecules-mediated biomimetic mineralization has been extensively investigated and applied to fabricate nano-assemblies with unique hierarchical architectures and salient properties. The confined-source ion diffusion plays a key role in the biomineralization process, but little investigative efforts have focused on it. Here, we developed a simple method to mimic the in vivo condition by a confined diffusion method, and hydroxyapatite nanoflower assemblies (HNAs) with exquisite hierarchical architectures were obtained. The HNAs were assembled from needle-like hybrid nanocrystals of hydroxyapatite and hyaluronan. The results revealed that the strong interactions between ions and hyaluronan led to the nucleation of hydroxyapatite and the following aggregation. The combination of the external diffusion field and the internal multiple interactions induced the self-assembling processes. Additionally, HNAs with colloid stability and excellent biocompatibility were proved to be a promising cargo carrier for intranuclear delivery. This work presents a novel biomimetic mineralization strategy based on confined diffusion system for fabricating delicate hydroxyapatite, which offers a new perspective for the development of biomimetic strategies.

Delicate Hybrid Laponite-Cyclic Poly(ethylene glycol) Nanoparticles as a Potential Drug Delivery System.

The objective of the study was to explore the feasibility of a new drug delivery system using laponite (LAP) and cyclic poly(ethylene glycol) (cPEG). Variously shaped and flexible hybrid nanocrystals were made by both the covalent and physical attachment of chemically homogeneous cyclized PEG to laponite nanodisc plates. The size of the resulting, nearly spherical particles ranged from 1 to 1.5 µm, while PEGylation with linear methoxy poly (ethylene glycol) (mPEG) resulted in fragile sheets of different shapes and sizes. When infused with 10% doxorubicin (DOX), a drug commonly used in the treatment of various cancers, the LAP-cPEG/DOX formulation was transparent and maintained liquid-like homogeneity without delamination, and the drug loading efficiency of the LAP-cPEG nano system was found to be higher than that of the laponite-poly(ethylene glycol) LAP-mPEG system. Furthermore, the LAP-cPEG/DOX formulation showed relative stability in phosphate-buffered saline (PBS) with only 15% of the drug released. However, in the presence of human plasma, about 90% of the drug was released continuously over a period of 24 h for the LAP-cPEG/DOX, while the LAP-mPEG/DOX formulation released 90% of DOX in a 6 h burst. The results of the cell viability assay indicated that the LAP-cPEG/DOX formulation could effectively inhibit the proliferation of A549 lung carcinoma epithelial cells. With the DOX concentration in the range of 1-2 µM in the LAP-cPEG/DOX formulation, enhanced drug effects in both A549 lung carcinoma epithelial cells and primary lung epithelial cells were observed compared to LAP-mPEG/DOX. The unique properties and effects of cPEG nanoparticles provide a potentially better drug delivery system and generate interest for further targeting studies and applications.

Bifunctional Strategy toward Constructing Perovskite/Upconversion Lab-on-Paper Photoelectrochemical Device for Sensitive Detection of Malathion.

Bifunctional nanocrystals which combine two kinds of materials into single nanoparticles hold great promise in photoelectrochemical (PEC) analysis, particularly for nanocrystals based on perovskite quantum dots (QDs) which generally exhibit excellent photoelectric activity yet poor stability and upconversion nanoparticles (UCNP) that normally suffer from negligible photoelectric activity. Therefore, to achieve good performance of the PEC bioassay platform, it is valuable to combine perovskite QDs with UCNP encapsulation and promote their advantages to form hybrid nanocrystals that are stable, NIR excitable, and photoelectric. Herein, the core-shell configuration of perovskite/upconversion CsPbBr2I@NaYF4:Yb,Tm (CPBI@UCNP) nanocrystals coupled with a NiMn-layered double hydroxide (NiMn-LDH)/CdS heterojunction to form a cascade sensitization structure was proposed to construct the lab-on-paper PEC device for ultrasensitive detection of malathion pesticides. Concretely, the bifunctional CPBI@UCNP nanocrystals that encapsulated CPBI QDs into UCNPs were employed as a nanoscale light source and sensitizer in the lab-on-paper system, which not only prevented the degradation of perovskite QDs but also overcame the negligible photoelectric performance of pristine UCNPs with the cooperation of photoactive CPBI QDs. The synergistic quenching effect, including fluorescence energy resonance transfer (FRET) and photoinduced electron transfer (PET), was created to realize enhanced PEC signal readout. Benefiting from the dynamic cascade sensitization structure of CPBI@UCNP/NiMn-LDH/CdS and synergistic quenching effect of FRET/PET, the ultrasensitive detection of malathion was achieved with high selectivity, reproducibility, and stability, which provided guidelines to employ perovskite/upconversion nanomaterials for lab-on-paper PEC analysis.

Efficient photocatalytic degradation of organic pollutants over TiO2 nanoparticles modified with nitrogen and MoS2 under visible light irradiation

Investigate the use of visible light to improve photocatalytic degradation of organic pollutants in wastewater. Nitrogen-doped titania and molybdenum sulfide nanocomposites (NTM NCs) with different weight ratios of MoS2 (1, 2, and 3 wt.%) synthesized by a solid state method applied to the photodegradation of methylene blue(MB) under visible light irradiation. The synthesized NTM composites were characterized by SEM, TEM, XRD, FT-IR, UV–Vis, DRS and PL spectroscopy. The results showed enhanced activity of NTM hybrid nanocrystals in oxidizing MB in water under visible light irradiation compared to pure TiO2. The photocatalytic performance of NTM samples increased with MoS2 content. The results show that the photodegradation efficiency of the TiO2 compound improved from 13 to 82% in the presence of N-TiO2 and to 99% in the presence of MoS2 containing N-TiO2, which is 7.61 times higher than that of TiO2. Optical characterization results show enhanced nanocomposite absorption in the visible region with long lifetimes between e/h+ at optimal N-TiO2/MoS2 (NTM2) ratio. Reusable experiments indicated that the prepared NTM NCs photocatalysts were stable during MB photodegradation and had practical applications for environmental remediation.