Bimetallic Nanoparticles: Enhanced Magnetic and Optical Properties for Emerging Biological Applications

Nanoarchitectonics for synergistic activity of multimetallic nanohybrids as a possible approach for antimicrobial resistance (AMR)

The global threat posed by antimicrobial resistance (AMR) to public health is an immensurable problem. The effectiveness of treating infections would be more at risk in the absence of effective antimicrobials. Researchers have shown an amplified interest in alternatives, such as developing advanced metallic nanohybrids as new therapeutic candidates for antibiotics due to their promising effectiveness against resistant microorganisms. In recent decades, the antimicrobial activity of monometallic nanoparticles has received extensive study and solid proof, providing new opportunities for developing multimetallic nanohybrid antimicrobials. Advanced metallic nanohybrids are an emerging remedy for a number of issues that develop in the field of medicine. Advanced metallic nanohybrids have shown a promising ability to combat resistant microorganisms due to their overall synergistic activity. Formulating advanced multimetallic nanohybrids falling under the umbrella of the growing field of nanoarchitectonics, which extends beyond nanotechnology. The underlying theory of nanoarchitectonics involves utilizing nanoscale units that follow the concepts of nanotechnology to architect nanomaterials. This review focuses on a comprehensive description of antimicrobial mechanisms of metallic nanohybrids and their enabling future insights on the research directions of developing the nanoarchitectonics of advanced multimetallic nanohybrids as novel antibiotics through their synergistic activity.

Magnetic nanomaterials mediate precise magnetic therapy

Magnetic nanoparticle (MNP)-mediated precision magnet therapy plays a crucial role in treating various diseases. This therapeutic strategy compensates for the limitations of low spatial resolution and low focusing of magnetic stimulation, and realizes the goal of wireless teletherapy with precise targeting of focal areas. This paper summarizes the preparation methods of magnetic nanomaterials, the properties of magnetic nanoparticles, the biological effects, and the measurement methods for detecting magnetism; discusses the research progress of precision magnetotherapy in the treatment of psychiatric disorders, neurological injuries, metabolic disorders, and bone-related disorders, and looks forward to the future development trend of precision magnet therapy.

B and N Codoped Cellulose-Supported Ag-/Bi-Doped Mo(S,O)3 Trimetallic Sulfo-Oxide Catalyst for Photocatalytic H2 Evolution Reaction and 4-Nitrophenol Reduction

Cellulose plays a significant role in designing efficient and stable cellulose-based metallic catalysts, owing to its surface functionalities. Its hydroxyl groups are used as anchor sites for the nucleation and growth of metallic nanoparticles and, as a result, improve the stability and catalytic activity. Meanwhile, cellulose is also amenable to surface modifications to be more suitable for incorporating and stabilizing metallic nanoparticles. Herein, the Ag-/Bi-doped Mo(S,O)3 trimetallic sulfo-oxide anchored on B and N codoped cellulose (B-N-C) synthesized by a facile approach showed excellent stability and catalytic activity for PHER at 573.28 μmol/h H2 with 25 mg of catalyst under visible light, and 92.3% of the 4-nitrophenol (4-NP) reduction was achieved within 135 min by in situ-generated protons. In addition to B and N codoping, our use of the calcination method for B-N-C preparation further increases the structural disorders and defects, which act as anchoring sites for Ag-/Bi-doped Mo(S,O)3 nanoparticles. The Ag-/Bi-doped Mo(S,O)3@B-N-C surface active site also stimulates H2O molecule adsorption and activation kinetics and reduces the photogenerated charge carrier's recombination rate. The Mo4+ → Mo6+ electron hopping transport and the O 2p and Bi 6s orbital overlap facilitate the fast electron transfer by enhancing the electron's lifetime and photoinduced charge carrier mobility, respectively. In addition to acting as a support, B-N-C provides a highly conductive network that enhances charge transport, and the relocated electron in B-N-C activates the H2O molecule, which enables Ag-/Bi-doped Mo(S,O)3@B-N-C to have appreciable PHER performance.

Au@Ag nanoparticles: an analytical tool to study the effect of tyrosine on dopamine levels

The neurotransmitter dopamine (DA) plays important roles in the human body, including regulatory functions, movement, memory and motivational control. The direct intake of DA is impossible as it cannot cross the blood-brain barrier (BBB) efficiently. Notably, l-tyrosine works as a precursor of DA in the human brain. Herein, we report an analytical method that strongly supports the hypothesis that the intake of tyrosine (Tyr)-rich food enhances DA levels. For this analysis, citrate-coated gold-core silver-shell nanoparticles (Au@Ag NPs) were synthesized. The interaction of DA with the Au@Ag NPs was investigated using multiple spectroscopic techniques, and different thermodynamic parameters were evaluated to assign the binding mechanism. Real sample analysis with Tyr-rich food was also conducted to study the effect of Tyr on DA levels. Analytical studies were performed to verify the outcomes of the present work. The limit of detection of the Au@Ag NPs-DA system for Tyr was found to be 1.64 mM. This study can contribute to development in the fields of medicine and pharmaceuticals, particularly in regard to neuromedicine. One of the major advantages of this investigation is that it will fuel research interest in the supplementation of neurotransmitters and help categorize Tyr as a dietary precursor of dopamine.

Machine Learning-Accelerated High-Throughput Computational Screening: Unveiling Bimetallic Nanoparticles with Peroxidase-Like Activity

Bimetallic nanoparticles (NPs) with peroxidase-like (POD-like) activity play a crucial role in biosensing, disease treatment, environmental management, and other fields. However, their development is impeded by a vast range of tunable properties in components and structures, making the establishment of structure-effect relationships and the discovery of active materials challenging. Addressing this, we established robust scaling relationships by meticulously analyzing the catalytic reaction networks of pure metal NPs, which laid the volcano-shaped correlation between the activity and O* adsorption energy. Utilizing these relationships, we introduced an innovative and versatile descriptor of the NPs, which was then integrated into a machine learning-accelerated high-throughput computational workflow, significantly boosting the predictive accuracy for the POD-like activity of bimetallic NPs. Our methodological approach enabled the successful prediction of activities for 1260 bimetallic NPs, leading to the identification of several highly effective catalysts. Furthermore, we distilled several strategies for designing efficient bimetallic NPs based on our screening results.

Fabrication and Characterization of Montmorillonite Clay/Agar-Based Magnetic Composite and Its Biological and Electrical Conductivity Evaluation

Montmorillonite clay and agar are naturally occurring materials of significant importance in designing biocompatible materials tailored for applications in biotechnology and medicine. The introduction of magnetic properties has the potential to significantly boost their characteristics and expand their applications. In this study, we have successfully synthesized highly intercalated magnetic composites, incorporating magnetic iron oxide nanoparticles (MNPs), montmorillonite clay (MMT), and agar (AG), through a thermo-physicomechanical method. Three samples of MMT-AG with 2, 1.5, and 0.5% MNPs and three sample composites of MNPs-AG with 2, 1, and 0.5% MMT clay are prepared. The synthesized composites were characterized by SEM, XRD, TGA, DTA, and FTIR. SEM analysis revealed a uniform dispersion of MNPs and MMT in the composite. The XRD pattern confirmed the presence of MNPs in the composite site. The TGA and DTA results demonstrated improved thermal stability due to the MNP incorporation. FTIR spectra showed all of the constituents of agar, MNPs, and MMT clay. The swelling ratio was observed to range from 835% to 1739%. The swelling study indicated an increased hydrophobicity with the addition of MNPs to the composite. Antibacterial activities revealed a significant inhibition of Escherichia coli (E. coli) growth by ranging from 10 to 19 nm in the composite. The composite also exhibited a considerable antioxidant action, with IC50 values of 7.96, 46.55, and 57.58 μg/mL, and electrical properties just like conductors.

Physical and chemical parameters determining the formation of gold-sp metal (Al, Ga, In, and Pb) nanoalloys

Alloying is a key step towards the fabrication of advanced and unique nanomaterials demanded by the next generation of nanotechnology solutions. In particular, the alloys of Au with the sp-metals are expected to have several appealing plasmonic and electronic properties for a wide range of applications in optics, catalysis, nanomedicine, sensing and quantum devices. However, little is known about the thermodynamic and synthetic factors leading to the successful alloying of Au and sp-metals at the nanoscale. In this work, Au-M nanoalloys, with M = Al, Ga, In, or Pb, have been synthesized by a green and single step laser ablation in liquid (LAL) approach in two environments (pure ethanol and anhydrous acetone). To delve deeper into the key parameters leading to successful alloying under the typical operating conditions of LAL, a multiparametric analysis was performed considering the mixing enthalpy from DFT calculations and other alloying descriptors such as the Hume-Rothery parameters. The results showed that the dominant factors for alloying change dramatically with the oxidative ability of the synthesis environment. In this way, the tendency of the four sp metals to alloy with gold was accurately predicted (R2 > 0.99) using only two and three parameters in anhydrous and non-anhydrous environments, respectively. These results are important to produce nanoalloys using LAL and other physical methods because they contribute to the understanding of factors leading to element mixing at the nanoscale under real synthetic conditions, which is crucial for guiding the realization of next-generation multifunctional metallic nanostructures.

Harnessing the potential of bimetallic nanoparticles: Exploring a novel approach to address antimicrobial resistance

The growing global importance of antimicrobial resistance (AMR) in public health has prompted the creation of innovative approaches to combating the issue. In this study, the promising potential of bimetallic nanoparticles (BMNPs) was investigated as a novel weapon against AMR. This research begins by elaborating on the gravity of the AMR problem, outlining its scope in terms of the effects on healthcare systems, and stressing the urgent need for novel solutions. Because of their unusual features and wide range of potential uses, bimetallic nanoparticles (BMNPs), which are tiny particles consisting of two different metal elements, have attracted a lot of interest in numerous fields. This review article provides a comprehensive analysis of the composition, structural characteristics, and several synthesis processes employed in the production of BMNPs. Additionally, it delves into the unique properties and synergistic effects that set BMNPs apart from other materials. This review also focuses on the various antimicrobial activities shown by bimetallic nanoparticles, such as the rupturing of microbial cell membranes, the production of reactive oxygen species (ROS), and the regulation of biofilm formation. An extensive review of in vitro studies confirms the remarkable antibacterial activity of BMNPs against a variety of pathogens and sheds light on the dose-response relationship. The efficacy and safety of BMNPs in practical applications are assessed in this study. It also delves into the synergistic effects of BMNPs with traditional antimicrobial drugs and their ability to overcome multidrug resistance, providing mechanistic insight into these phenomena. Wound healing, infection prevention, and antimicrobial coatings on medical equipment are only some of the clinical applications of BMNPs that are examined, along with the difficulties and possible rewards of clinical translation. This review covers nanoparticle-based antibacterial regulation and emerging uses. The essay concludes with prospects for hybrid systems, site-specific targeting, and nanoparticle-mediated gene and drug delivery. In summary, bimetallic nanoparticles have surfaced as a potential solution, offering the public a more promising and healthier future.

Cu-Co Bimetallic Catalyst-based Electrochemical Sensing Platform for Determination of Bisoprolol in Clinical Samples

BACKGROUND

Bisoprolol (BIS) is a selective beta-blocker. It has been successfully used to treat hypertension and angina pectoris. An overdose of BIS can lead to serious complications. An overdose is a medical emergency that requires immediate medical attention to overcome the adverse effects of the overdose. Hence, sensitive, reliable, and cost-effective methods are required for the determination of BIS.

METHODS

In this work, a new electrochemical sensing platform based on a bimetallic catalyst was developed for the determination of BIS. The Cu-Co nanocatalyst was easily synthesized by galvanic displacement onto a carbon paste electrode (CPE). Then, field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), and cyclic voltammetry (CV) were utilized for the characterization of the Cu-Co catalyst.

RESULTS

The galvanic displacement of Cu metal significantly affected the electro-catalytic behavior of the Cu-Co catalyst and the Cu-Co/CPE electrode displayed a very sensitive and accurate response towards BIS. Under optimized conditions, the response was linear in the 3 to 120 μM concentration range, sensitivity of 631.1 μA mM-1 and a detection limit of as low as 0.4 μM using cyclic voltammetry. The simple proposed method was also successfully employed in the analysis of BIS in biological and pharmaceutical samples. The advantages of Cu-Co/CPE are its fast and simple manufacturing and the possibility of a repeated surface regeneration of the sensing platform, as well as its application for the detection of BIS in tablets and biological samples, making Cu-Co significant promise for use in clinical diagnostics. Besides, the synthesized catalysts showed excellent reusability and stability.

CONCLUSION

The presence of Cu metal due to galvanic displacement increased the sensitivity. These findings suggest that the new nanocatalyst has potential applications in sensors and electronics.

Green synthesis trends and potential applications of bimetallic nanoparticles towards the sustainable development goals 2030

The world faces threats that the United Nations has classified into 17 categories with different objectives as solutions for each challenge that are enclosed in the Sustainable Development Goals (SDGs). These actions involved the widespread use of science and technology as pathways to ensure their implementation. In this regard, sustainability science seeks the research community's contribution to addressing sustainable development challenges. Specifically, nanotechnology has been recognized as a key tool to provide disruptive and effective strategies to reach the SDGs. This review proposes the application of bimetallic nanoparticle substances capable of providing possible solutions to achieve target SDG 3: good health and well-being, SDG 6: clean water and sanitation, and SDG 12: responsible consumption and production. Furthermore, the term green nanotechnology is introduced in each section to exemplify how green synthesized bimetallic nanoparticles have been used to resolve each target SDG. This review also outlines the current scenario regarding the utilization of metallic nanomaterials in the market, together with the upscaling challenges and the lack of understanding of the long-term effects and hazards to the environment regarding bimetallic nanoparticles.

A review of physical, chemical and biological synthesis methods of bimetallic nanoparticles and applications in sensing, water treatment, biomedicine, catalysis and hydrogen storage

This article provides an in-depth analysis of various fabrication methods of bimetallic nanoparticles (BNP), including chemical, biological, and physical techniques. The review explores BNP's diverse uses, from well-known applications such as sensing water treatment and biomedical uses to less-studied areas like breath sensing for diabetes monitoring and hydrogen storage. It cites results from over 1000 researchers worldwide and >300 peer-reviewed articles. Additionally, the article discusses current trends, actionable recommendations, and the importance of synthetic analysis for industry players looking to optimize manufacturing techniques for specific applications. The article also evaluates the pros and cons of various fabrication methods, highlighting the potential of plant extract synthesis for mass production of capped BNPs. However, it warns that this method may not be suitable for certain applications requiring ligand-free surfaces. In contrast, physical methods like laser ablation offer better control and reactivity, especially for applications where ligand-free surfaces are critical. The report underscores the environmental benefits of plant extract synthesis compared to chemical methods that use hazardous chemicals and pose risks to extraction, production, and disposal. The article emphasizes the need for life cycle assessment (LCA) articles in the literature, given the growing volume of research on nanotechnology materials. This article caters to researchers at all stages and applies to various fields applying nanomaterials.

Recent advances in synthesis and characterization of iron-nickel bimetallic nanoparticles and their applications as photo-catalyst and fuel additive

Iron-nickel bimetallic nanoparticles (Fe-Ni BMNPs) are prepared by combining two different metals by using the bottom-up approach. The resulting material has entirely different properties as compared to both the metals. The product is examined by using different analytical instruments such as.; scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), MDIJADE, ORIGIN pro to characterize their morphology, crystallinity and elemental composition and the final data has been statistically analyzed. SEM findings show that most nanoparticles are irregular in form and range in size from 10 nm to 100 nm. The findings of the TEM verified that the particles between 10 nm and 50 nm are irregular in size shape. The products acquired utilized as a fuel additive to monitor oil effectiveness by studying various parameters. The degradation of methylene blue dye depends directly on the concentration of the nanocatalyst. Different parameters also use the freshly prepared bimetallic nanocatalyst to investigate the efficacy of the kerosene fuel. By adding a tiny quantity of the nanocatalyst, the value of the flash point and fire point is significantly reduced. The nanocatalyst does not affect the cloud point and pour point to a large extent. The bimetallic nanocatalyst therefore has very excellent catalytic characteristics.

Light-Driven Catalytic Activity of Green-Synthesized SnO2/WO3-x Hetero-nanostructures

This work reports an environmentally friendly and economically feasible green synthesis of monometallic oxides (SnO₂ and WO₃) and their corresponding mixed metal oxide (SnO₂/WO_3-x) nanostructures from the aqueous Psidium guajava leaf extract for light-driven catalytic degradation of a major industrial contaminant, methylene blue (MB). P. guajava is a rich source of polyphenols that acts as a bio-reductant as well as a capping agent in the synthesis of nanostructures. The chemical composition and redox behavior of the green extract were investigated by liquid chromatography-mass spectrometry and cyclic voltammetry, respectively. Results acquired by X-ray diffraction and Fourier transform infrared spectroscopy confirm the successful formation of crystalline monometallic oxides (SnO₂ and WO₃) and bimetallic SnO₂/WO_3-x hetero-nanostructures capped with polyphenols. The structural and morphological aspects of the synthesized nanostructures were analyzed by transmission electron microscopy and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. Photocatalytic activity of the synthesized monometallic and hetero-nanostructures was investigated for the degradation of MB dye under UV light irradiation. Results indicate a higher photocatalytic degradation efficiency for mixed metal oxide nanostructures (93.5%) as compared to pristine monometallic oxides SnO₂ (35.7%) and WO₃ (74.5%). The hetero-metal oxide nanostructures prove to be better photocatalysts with reusability up to 3 cycles without any loss in degradation efficiency or stability. The enhanced photocatalytic efficiency is attributed to a synergistic effect in the hetero-nanostructures, efficient charge transportation, extended light absorption, and increased adsorption of dye due to the enlarged specific surface area.

Intense up-conversion luminescence from Dy3+-doped multi-component telluroborate glass matrix: Role of CuO nanoparticles embedment

This paper reports an intense up-conversion luminescence from Dy³⁺-doped strontium-telluro-alumino-magnesium-borate glasses for the first time. The samples were made via the melt-quenching method and characterized to determine the influence of various CuO nanoparticles contents change on their up-conversion emission traits. Absorption spectral data were used to calculate the Judd-Ofelt intensity parameters. The sample without CuO nanoparticles revealed two intense photoluminescence up-conversion emission peaks at 478 and 570 nm. In addition, CuO nanoparticles-activated sample displayed about 1.4-fold up-conversion emission intensity improvement due to strong light absorption in the visible to the infrared region at 799 nm excitation. The stimulated emission cross-section of the CuO nanoparticles-activated glasses was increased from 102.4 × 10^-23 to 1301.1 × 10^-23 cm² (nearly 10-fold amplification) while the branching ratio was reduced to 66.9%. Thus, CuO nanoparticles as an additive in the current glass matrix enhanced the up-conversion emission and strengthened the associated nonlinear optical properties. CIE 1931 color matching revealed the influence of CuO in modifying the up-conversion color coordinates, thereby improving the white color purity. The achieved up-conversion emission coupled with the color tunability of the proposed glasses may be advantageous for the up-conversion UV tunable laser making.

Silver and Gold Containing Compounds of p-Block Elements As Perspective Materials for UV Plasmonics

We present a review of phase formation tendencies, methods for preparation and optical properties of alloys and compounds from the binary systems of silver or gold with metals and metalloids from the p-block of the Periodic system of elements. Reference data about the homogeneity regions in the systems of interest, together with information about the crystalline structure of existing indexed compounds in them, is proposed and statistically analyzed. General background for the synthesis of intermetallic alloys and compounds, and the tendencies for their preparation for plasmonic purposes are presented. The high plasma frequency, ω_p of p-block metals makes their alloys with silver and gold an interesting object of study, due to the possibility of ω_p variation over a wide interval in the ultraviolet (UV) spectral region with a view to finding more efficient materials for excitation of a localized surface plasmon resonance (LSPR) necessary for various applications and techniques operating in this part of the electromagnetic spectrum. Unlike the alloys between the noble metals Cu, Ag, and Au, which form continuous series of solid solutions, different areas can be observed in the phase diagrams of the Ag(Au)-p-block systems, containing solid solutions, intermetallic compounds, and heterogeneous mixtures. The ability to vary the plasma frequency of solid solutions, like the alloys between the noble metals Cu, Ag, and Au, is the reason to pay attention to the compositions of the Ag(Au-p-block systems that fall in these regions of their phase diagrams. The analysis of the published results for complex permittivity shows that the addition of small amounts of conductive p-block elements to noble metals reduces the energy gap for interband transitions and increases their plasmonic activity in the UV spectral range. The article analyzes the relationship between electrical resistivity and LSPR excitation efficiency, which shows that the intermetallic compounds from Ag(Au)-p-block systems with a well-ordered crystalline structure and good conductivity level can be more effective materials for UV plasmonics than the boundary solid solutions. Intermetallic compounds can be easily obtained in the form of bulk samples, thin films, and nanoparticles with controlled size and geometric shape. The spectral dependences of the plasmon efficiency of the intermetallic compounds, determined from their complex permittivity functions, show that they are promising materials for excitation of LSPR in the UV spectral region.

Sericin mediated gold/silver bimetallic nanoparticles and exploration of its multi-therapeutic efficiency and photocatalytic degradation potential

The current investigation aimed at bimetallic gold-silver nanoparticles (Au/Ag NPs), here called BM-GS NPs, synthesis using sericin protein as the reducing agent in an easy, cost-effective, and sustainable way. The obtained BM-GS NPs were characterized by UV-Visible spectroscopy, Transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDS), atomic force microscopy (AFM), Dynamic light scattering (DLS) and Zeta potential, X-ray Powder Diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and Thermogravimetric analysis followed by evaluation of its multitherapeutic and photocatalytic degradation potentials. The TEM analysis revealed its spherical nature and the EDS result displayed the presence of both Ag and Au elements, confirming the synthesis of BM-GS NPs. The XRD pattern verified the crystalline nature of the nanoparticles (NPs). The DLS analysis showed an average size of 86.08 d nm and the zeta potential showed a highly negative value (-26.3 mV) which specifies that the generated bimetallic NPs are stable. The BM-GS NPs exhibited positive wound healing potential (with 63.38% of wound closure rate at 25 μg/ml, as compared to 54.42% by the untreated control) with very negligible toxicity effect on the cell viability of the normal keratinocyte cells. It also demonstrated promising antioxidant properties with 65.00%, 69.23%, and 63.03% activity at 100 μg/ml concentration for ABTS (2, 2-azinobis) (3-ethylbenzothiazoline-6-sulfonic acid)), DPPH (1, 1 diphenyl-2-picrylhydrazyl) and SOD (superoxide dismutase enzyme) assays respectively, antidiabetic potential (with a significantly high α-glucosidase inhibition potential of 99.69% at 10μg/ml concentration and 62.11% of α-amylase enzyme inhibition at 100 μg/ml concentration) and moderate tyrosinase inhibitory potential (with 17.09% at 100 μg/ml concentration). Besides, it displayed reasonable antibacterial potential with the diameter of zone of inhibition ranging between 10.89 and 12.39 mm. Further, its antibacterial mode of action reveals that its effects could be due to being very smaller, the NPs could have penetrated inside the cellular membrane thereby causing rupture and damage to the interior materials leading to cellular lysis. The photocatalytic evaluation showed that synthesized BM-GS NPs have the efficiency of degrading methylene blue dye by 34.70% within 3 h of treatment. The above findings revealed the multi-therapeutic efficacy of the sericin globular protein-mediated BM-GS NPs and its potential future applications in the cosmetics and food sector and environmental contamination management industries.

Advanced Plasmonic Nanoparticle-Based Techniques for the Prevention, Detection, and Treatment of Current COVID-19

Coronavirus is an ongoing global pandemic caused by severe acute respiratory syndrome coronavirus 2. Coronavirus disease 2019 known as COVID-19 is the worst pandemic since World War II. The outbreak of COVID-19 had a significant repercussion on the health, economy, politics, and environment, making coronavirus-related issues more complicated and becoming one of the most challenging pandemics of the last century with deadly outcomes and a high rate of the reproduction number. There are thousands of different types - or variants - of COVID circulating across the world. Viruses mutate all the time; it emphasizes the critical need for the designing of efficient vaccines to prevent virus infection, early and fast diagnosis, and effective antiviral and protective therapeutics. In this regard, the use of nanotechnology offers new opportunities for the development of novel strategies in terms of prevention, diagnosis, and treatment of COVID-19. This review presents an outline of the platforms developed using plasmonic nanoparticles in the detection, treatment, and prevention of SARS-CoV-2. We select the best strategies in each of these approaches. The properties of metallic plasmon NPs and their relevance in the development of novel point-of-care diagnosis approaches for COVID-19 are highlighted. Also, we discuss the current challenges and the future perspectives looking towards the clinical translation and the commercial aspects of nanotechnology and plasmonic NP-based diagnostic tools and therapy to fight COVID-19 pandemic. The article could be of significance for researchers dedicated to developing suitable plasmonic detection tools and therapy approaches for COVID-19 viruses and future pandemics.

Recent Developments in Plasmonic Alloy Nanoparticles: Synthesis, Modelling, Properties and Applications

Despite the traditional plasmonic materials are counted on one hand, there are a lot of possible combinations leading to alloys with other elements of the periodic table, in particular those renowned for magnetic or catalytic properties. It is not a surprise, therefore, that nanoalloys are considered for their ability to open new perspectives in the panorama of plasmonics, representing a leading research sector nowadays. This is demonstrated by a long list of studies describing multiple applications of nanoalloys in photonics, photocatalysis, sensing and magneto-optics, where plasmons are combined with other physical and chemical phenomena. In some remarkable cases, the amplification of the conventional properties and even new effects emerged. However, this field is still in its infancy and several challenges must be overcome, starting with the synthesis (control of composition, crystalline order, size, processability, achievement of metastable phases and disordered compounds) as well as the modelling of the structure and properties (accuracy of results, reliability of structural predictions, description of disordered phases, evolution over time) of nanoalloys. To foster the research on plasmonic nanoalloys, here we provide an overview of the most recent results and developments in the field, organized according to synthetic strategies, modelling approaches, dominant properties and reported applications. Considering the several plasmonic nanoalloys under development as well as the large number of those still awaiting synthesis, modelling, properties assessment and technological exploitation, we expect a great impact on the forthcoming solutions for sustainability, ultrasensitive and accurate detection, information processing and many other fields.

Single-Step Fabrication of Au-Fe-BaTiO3 Nanocomposite Thin Films Embedded with Non-Equilibrium Au-Fe Alloyed Nanostructures

Nanocomposite thin film materials present great opportunities in coupling materials and functionalities in unique nanostructures including nanoparticles-in-matrix, vertically aligned nanocomposites (VANs), and nanolayers. Interestingly the nanocomposites processed through a non-equilibrium processing method, e.g., pulsed laser deposition (PLD), often possess unique metastable phases and microstructures that could not achieve using equilibrium techniques, and thus lead to novel physical properties. In this work, a unique three-phase system composed of BaTiO₃ (BTO), with two immiscible metals, Au and Fe, is demonstrated. By adjusting the deposition laser frequency from 2 Hz to 10 Hz, the phase and morphology of Au and Fe nanoparticles in BTO matrix vary from separated Au and Fe nanoparticles to well-mixed Au-Fe alloy pillars. This is attributed to the non-equilibrium process of PLD and the limited diffusion under high laser frequency (e.g., 10 Hz). The magnetic and optical properties are effectively tuned based on the morphology variation. This work demonstrates the stabilization of non-equilibrium alloy structures in the VAN form and allows for the exploration of new non-equilibrium materials systems and their properties that could not be easily achieved through traditional equilibrium methods.

Plasmonic Hybrid Nanostructures in Photocatalysis: Structures, Mechanisms, and Applications

(Sun)Light is an abundantly available sustainable source of energy that has been used in catalyzing chemical reactions for several decades now. In particular, studies related to the interaction of light with plasmonic nanostructures have been receiving increased attention. These structures display the unique property of localized surface plasmon resonance, which converts light of a specific wavelength range into hot charge carriers, along with strong local electromagnetic fields, and/or heat, which may all enhance the reaction efficiency in their own way. These unique properties of plasmonic nanoparticles can be conveniently tuned by varying the metal type, size, shape, and dielectric environment, thus prompting a research focus on rationally designed plasmonic hybrid nanostructures. In this review, the term "hybrid" implies nanomaterials that consist of multiple plasmonic or non-plasmonic materials, forming complex configurations in the geometry and/or at the atomic level. We discuss the synthetic techniques and evolution of such hybrid plasmonic nanostructures giving rise to a wide variety of material and geometric configurations. Bimetallic alloys, which result in a new set of opto-physical parameters, are compared with core-shell configurations. For the latter, the use of metal, semiconductor, and polymer shells is reviewed. Also, more complex structures such as Janus and antenna reactor composites are discussed. This review further summarizes the studies exploiting plasmonic hybrids to elucidate the plasmonic-photocatalytic mechanism. Finally, we review the implementation of these plasmonic hybrids in different photocatalytic application domains such as H₂ generation, CO₂ reduction, water purification, air purification, and disinfection.

Stability, Energetic, and Reactivity Properties of NiPd Alloy Clusters Deposited on Graphene with Defects: A Density Functional Theory Study

Graphene with defects is a vital support material since it improves the catalytic activity and stability of nanoparticles. Here, a density functional theory study was conducted to investigate the stability, energy, and reactivity properties of Ni_nPd_n (n = 1–3) clusters supported on graphene with different defects (i.e., graphene with monovacancy and pyridinic N-doped graphene with one, two, and three N atoms). On the interaction between the clusters and graphene with defects, the charge was transferred from the clusters to the modified graphene, and it was observed that the binding energy between them was substantially higher than that previously reported for Pd-based clusters supported on pristine graphene. The vertical ionization potential calculated for the clusters supported on modified graphene decreased compared with that calculated for free clusters. In contrast, vertical electron affinity values for the clusters supported on graphene with defects increased compared with those calculated for free clusters. In addition, the chemical hardness calculated for the clusters supported on modified graphene was decreased compared with free clusters, suggesting that the former may exhibit higher reactivity than the latter. Therefore, it could be inferred that graphene with defects is a good support material because it enhances the stability and reactivity of the Pd-based alloy clusters supported on PNG.

AuCo nanoparticles: ordering, magnetisation, and morphology trends predicted by DFT

The rapid development of applications relying on magnetism at the nanoscale has put a spotlight on nanoparticles with novel morphologies that are associated with enhanced electronic and magnetic properties. In this quest, nanoalloys combining highly magnetic cobalt and weakly reactive gold could offer many application-specific advantages, such as strong magnetic anisotropy. In the present study, we have employed density functional theory (DFT) calculations to provide a systematic overview of the size- and morphology-dependence of the energetic order and magnetic properties of AuCo nanoparticles up to 2.5 nm in diameter. The core-shell icosahedron was captured as the most favourable morphology, showing a small preference over the core-shell decahedron. However, the magnetic properties (total magnetic moments and magnetic anisotropy) were found to be significantly improved within the L1₀ ordered structures, even in comparison to monometallic Co nanoparticles. Atom-resolved charges and orbital moments accessed through the DFT analysis of the electronic level properties permitted insight into the close interrelation between the AuCo nanoparticle morphology and their magnetism. These results are expected to assist in the design of tailored magnetic AuCo nanoalloys for specific applications.

Plant-Based Bimetallic Silver-Zinc Oxide Nanoparticles: A Comprehensive Perspective of Synthesis, Biomedical Applications, and Future Trends

The universal emphasis on the study of green nanotechnology has led to biologically harmless uses of wide-ranged nanomaterials. Nanotechnology deals with the production of nanosized particles with regular morphology and properties. Various researches have been directed on nanomaterial synthesis by physical, chemical, and biological means. Understanding the safety of both environment and in vivo, a biogenic approach particularly plant-derived synthesis is the best strategy. Silver-zinc oxide nanoparticles are most effective. Moreover, these engineered nanomaterials via morphological modifications attain improved performance in antimicrobial, biomedical, environmental, and therapeutic applications. This article evaluates manufacturing strategies for silver-zinc oxide nanoparticles via plant-derived means along with highlighting their broad range of uses in bionanotechnology.

Plant Extracts Mediated Metal-Based Nanoparticles: Synthesis and Biological Applications

The vastness of metal-based nanoparticles has continued to arouse much research interest, which has led to the extensive search and discovery of new materials with varying compositions, synthetic methods, and applications. Depending on applications, many synthetic methods have been used to prepare these materials, which have found applications in different areas, including biology. However, the prominent nature of the associated toxicity and environmental concerns involved in most of these conventional methods have limited their continuous usage due to the desire for more clean, reliable, eco-friendly, and biologically appropriate approaches. Plant-mediated synthetic approaches for metal nanoparticles have emerged to circumvent the often-associated disadvantages with the conventional synthetic routes, using bioresources that act as a scaffold by effectively reducing and stabilizing these materials, whilst making them biocompatible for biological cells. This capacity by plants to intrinsically utilize their organic processes to reorganize inorganic metal ions into nanoparticles has thus led to extensive studies into this area of biochemical synthesis and analysis. In this review, we examined the use of several plant extracts as a mediating agent for the synthesis of different metal-based nanoparticles (MNPs). Furthermore, the associated biological properties, which have been suggested to emanate from the influence of the diverse metabolites found in these plants, were also reviewed.

Recent Advances in the Preparation of Barium Sulfate Nanoparticles: A Mini-Review

The potential for barium sulphate nanoparticles to be used in a variety of important fields has sparked a lot of attention. Methods for obtaining this material by milling (top-down approach) are not very popular due to the difficulty of controlling the size and shape of particles, as well as changes in their physicochemical properties during milling. More promising is the bottom-up approach, which is the interaction of Ba2+ and SO42− ions in a liquid environment. Direct precipitation is the simplest method; however, it does not allow control of the particle size. Microemulsions, microreactors membrane dispersion, as well as spinning disc reactors are used to overcome drawbacks of direct precipitation and allow control of particle size and shape. This is ensured mainly by intensive controlled micromixing of the precursors with concentrations close to saturated ones. The present review focuses on recent advances in the production of barium sulfate nanoparticles using various approaches, as well as their advantages and limitations. The issues of scaling up the techniques are also considered, and promising methods for obtaining BaSO4 nanoparticles are also discussed.

Sustainable, Green, and Continuous Synthesis of Fivefold Palladium Nanorods Using l-Ascorbic Acid in a Segmented Millifluidic Flow Reactor

Pd nanorods (PdNRs) have recently come to attention due to their wide array of applications. The green synthesis of PdNR with a relatively high yield and high aspect ratio is challenging. A continuous millifluidic flow reactor (CMFR) has been explored to precisely control mass and heat transfer as well as mixing in the PdNR synthesis processes. CMFRs demonstrate a few drawbacks, such as the presence of parabolic velocity profile in the laminar flow of the reaction solution, causing uneven axial residence time distribution. The CMFRs are likely to show irreversible fouling, which may cause the product quality to deteriorate or result in the channel being clogged. These shortcomings can be avoided or minimized using a segmented millifluidic flow reactor (SMFR) that consists of the solution forming a train of individual segments in another inert medium. This study explores the use of a sustainable reducing agent (l-ascorbic acid) in the presence of potassium bromide (KBr) as the capping agent and poly(vinyl pyrrolidone) (PVP) as the stabilizing agent for PdNR synthesis in an SMFR employing compartmentalized flow of a reaction solution, in which liquid segments consisting of a reaction solution will be immersed in the steam generated by boiling of the solvent water. The effect of reaction parameters such as reagent concentration has been studied on the size and morphology of synthesized Pd nanostructures. A kinetic study has been conducted to calculate the rate of reduction that can be used as a quantitative measure for manipulation of the type and relative concentration of initially formed seeds. It has been shown that the initial reduction rate during the first 45 min of residence time of the millifluidic reactor is about 66% faster compared to the rest of the reaction. A filtration procedure has been utilized to separate Pd nanostructures other than nanorods synthesized in the SMFR.

Gold nanoparticle-based optical nanosensors for food and health safety monitoring: recent advances and future perspectives

Modern society has been facing serious health-related problems including food safety, diseases and illness. Hence, it is urgent to develop analysis methods for the detection and control of food contaminants, disease biomarkers and pathogens. As the traditional instrumental methods have several disadvantages, including being time consuming, and having high cost and laborious procedures, optical nanosensors have emerged as promising alternative or complementary approaches to those traditional ones. With the advantages of simple preparation, high surface-to-volume ratio, excellent biocompatibility, and especially, unique optical properties, gold nanoparticles (AuNPs) have been demonstrated as excellent transducers for optical sensing systems. Herein, we provide an overview of the synthesis of AuNPs and their excellent optical properties that are ideal for the development of optical nanosensors based on local surface plasmon resonance (LSPR), colorimetry, fluorescence resonance energy transfer (FRET), and surface-enhanced Raman scattering (SERS) phenomena. We also review the sensing strategies and their mechanisms, as well as summarizing the recent advances in the monitoring of food contaminants, disease biomarkers and pathogens using developed AuNP-based optical nanosensors in the past seven years (2015-now). Furthermore, trends and challenges in the application of these nanosensors in the determination of those analytes are discussed to suggest possible directions for future developments.

Mapping the effects of physical and chemical reduction parameters on local atomic distributions within bimetallic nanoparticles

Bimetallic nanoparticles prove advantageous over their monometallic counterparts due to the tunable, hybrid properties that result from combining different atomic species in a controlled way. The favorable optical and catalytic properties resulting from AgAu nanoparticle formation have been widely attributed to the existence of Ag-Au bonds, the maximization of which assumes the formation of a homogeneous alloy. Despite the importance of atomic scale structure in these systems, synthetic studies are typically not paired with structural characterization at the atomic scale. Herein, a comprehensive synthetic exploration of physical and chemical reduction parameters of resulting nanoparticle products is complemented with thorough X-ray characterization to probe how these parameters affect atomic scale alloy distributions within AgAu nanoparticles. Presented evidence shows Ag is substantially underincorporated into nanoparticle constructs compared with solution Ag : Au ratios regardless of precursor : reductant ratio or volume of reductant added. Both Ag and Au exhibit significant local clustering, with Ag distributed preferentially towards the nanoparticle surface. Most significantly, the results of this investigation suggest that reduction parameters alone can affect the local alloy distributions and homogeneity within bimetallic nanoparticles, even when the ratio of metallic precursors remains constant. Overall, this investigation presents the ability to control alloy distributions using kinetics and provides new considerations for optimizing synthetic methods to produce functional bimetallic nanoparticles.

Probing Optical Nonlinearities of Unconventional Glass Nanocomposites Made of Ionic Liquid Crystals and Bimetallic Nanoparticles

In this paper, we report the synthesis and characterization of unconventional nanocomposites made of bimetallic nanoparticles dispersed in a liquid crystal glass. Core-shell bimetallic nanoparticles (Ag/Au or Au/Ag) and Ag-Au bimetallic nanoalloys are synthesized using cadmium alkanoate glass-forming liquid crystals as nanoreactors. Optical spectra of the produced glassy nanocomposites exhibit a distinctive absorption peak due to a surface plasmon resonance. In addition, these unusual materials demonstrate a strong nonlinear–optical response probed by means of the Z-scan technique. The use of near-infrared (1064 nm) and visible (532 nm) nanosecond laser pulses reveal a variety of nonlinear–optical mechanisms that depend on the composition of the studied nanocomposites. Our results indicate that metal alkanoate-based glass-forming ionic liquid crystals with embedded plasmonic nanoparticles are promising, yet they are overlooked photonic nanomaterials suitable for optical and nonlinear-optical applications.

Combustion-assisted green-synthesized magnesium-doped cadmium ferrite nanoparticles for multifunctional applications

Magnesium-doped cadmium ferrite nanoparticles, MgXCd1−XFe2O4 (where, X = 0, 0.2, 0.4, 0.6, 0.8, 1) were synthesized by a combustion method using curd as fuel.

Oral Cancer Theranostic Application of FeAu Bimetallic Nanoparticles Conjugated with MMP-1 Antibody

Metastatic oral squamous cell carcinoma (SCC) displays a poor disease prognosis with a 5-year survival rate of 39%. Chemotherapy has emerged as the mainstream treatment against small clusters of cancer cells but poses more risks than benefits for metastatic cells due to the non-specificity and cytotoxicity. To overcome these obstacles, we conjugated antibodies specific for matrix metalloproteinase-1 (MMP-1), a prognostic biomarker of SCC, to iron–gold bimetallic nanoparticles (FeAu NPs) and explored the capability of this complex to target and limit SSC cell growth via magnetic field-induced hyperthermia. Our results showed that 4.32 ± 0.79 nm sized FeAu NPs were superparamagnetic in nature with a saturation magnetization (Ms) of 5.8 emu/g and elevated the media temperature to 45 °C, confirming the prospect to deliver hyperthermia. Furthermore, conjugation with MMP-1 antibodies resulted in a 3.07-fold higher uptake in HSC-3 (human tongue squamous cell carcinoma) cells as compared to L929 (fibroblast) cells, which translated to a 5-fold decrease in cell viability, confirming SCC targeting. Finally, upon magnetic stimulation, MMP-1-FeAu NPs conjugate triggered 89% HSC-3 cellular death, confirming the efficacy of antibody-conjugated nanoparticles in limiting SCC growth. The synergistic effect of biomarker-specific antibodies and magnetic nanoparticle-induced hyperthermia may open new doors towards SCC targeting for improved disease prognosis.

Fe3O4 Nanoparticles: Structures, Synthesis, Magnetic Properties, Surface Functionalization, and Emerging Applications

Magnetite (Fe3O4) nanoparticles (NPs) are attractive nanomaterials in the field of material science, chemistry, and physics because of their valuable properties, such as soft ferromagnetism, half-metallicity, and biocompatibility. Various structures of Fe3O4 NPs with different sizes, geometries, and nanoarchitectures have been synthesized, and the related properties have been studied with targets in multiple fields of applications, including biomedical devices, electronic devices, environmental solutions, and energy applications. Tailoring the sizes, geometries, magnetic properties, and functionalities is an important task that determines the performance of Fe3O4 NPs in many applications. Therefore, this review focuses on the crucial aspects of Fe3O4 NPs, including structures, synthesis, magnetic properties, and strategies for functionalization, which jointly determine the application performance of various Fe3O4 NP-based systems. We first summarize the recent advances in the synthesis of magnetite NPs with different sizes, morphologies, and magnetic properties. We also highlight the importance of synthetic factors in controlling the structures and properties of NPs, such as the uniformity of sizes, morphology, surfaces, and magnetic properties. Moreover, emerging applications using Fe3O4 NPs and their functionalized nanostructures are also highlighted with a focus on applications in biomedical technologies, biosensing, environmental remedies for water treatment, and energy storage and conversion devices.

Bimetallic nanocomposite (Ag-Au, Ag-Pd, Au-Pd) synthesis using gum kondagogu a natural biopolymer and their catalytic potentials in the degradation of 4-nitrophenol

Bimetallic nanoparticles (BNPs) constitute two different metal elements and exhibit relatively superior mechanistic and catalytic efficacies owing to their synergistic functions over monometallic nanoparticles. In the present study various bimetallic Ag-Au, Ag-Pd, Au-Pd nanoparticles were synthesized using a natural biopolymer gum kondagogu (GK) as a reducing and capping agent, by a simple and cost-effective method. The synthesized BNPs when characterized using UV-vis spectroscopy revealed a specific surface plasmon resonance band (SPR) of each nanocomposite. The average particle size of Ag-Au, Ag-Pd, and Au-Pd BNPs was found to be 23 ± 10.3, 21 ± 7.6, and 23 ± 9.4 nm respectively based on transmission electron microscopy analysis. Surface morphology and functional groups on the gum matrix of GK-BNPs were analyzed by XRD and FT-IR respectively. The bimetallic nanocomposites were evaluated for their catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol in the presence of NaBH₄. The kinetic studies performed, depicted rate constants for Ag-Au, Ag-Pd, and Au-PdNPs as 0.31, 0.39, and 0.28 min^-1 respectively. The catalytic efficiencies of three bimetallic nanocomposites were of the following order Ag-Pd > Ag-Au > Au-Pd. This study establishes the catalytic potentials of the three different bimetallic nanocomposites in the reduction of 4-NP an environmental pollutant, and the impact of their synergistic property.

Strategy to Design-Synthesize Bimetallic Nanostructures Using the Alcohol Reduction Method

Bimetallic nanomaterials have attracted much attention from various fields such as catalysis, optics, magnetism, and so forth. The functionality of such particles is influenced very much by the intermetallic interactions than their individual contribution. However, compared with the synthesis of monometallic nanoparticles, the reaction parameters that need to be controlled for tuning the size, shape, composition, and crystal structure of bimetallic nanoparticles becomes challenging. This study focuses on synthesizing of bimetallic nanostructures using the alcohol reduction method, where the control over the reducing power is conceivable by varying the combination of the alcohol type, complexing agent, and metal salts. Consequently, various Cu-Co nanostructures such as Cu-Co core-shell (size ranged between 40 and 15 nm) and hollow alloy nanoparticles and nanotubes were successfully synthesized by incorporating diffusion and etching phenomena during the reduction reaction. Moreover, time-resolved sampling revealed that the formation of a Cu-Co alloy hollow nanostructure has been realized by the diffusion of the Cu core into the Co shell by controlling the reduction time gap between Cu and Co and the crystal structure besides the reduction sequences. It should be noted that the synthesis of a high-temperature (∼1300 °C) Cu-Co alloy phase was carried out at 170 °C. Among the Cu-Co alloy nanostructures, Cu-Co hollow alloy nanoparticles exhibited enhanced catalytic activity compared to metallic Cu and other Cu-Co nanostructures from the degradation reaction of methylene blue. The enhanced catalytic performance was considered to be mainly due to the alloy structure.

Disposable Paper-Based Biosensors for the Point-of-Care Detection of Hazardous Contaminations-A Review

The fast detection of trace amounts of hazardous contaminations can prevent serious damage to the environment. Paper-based sensors offer a new perspective on the world of analytical methods, overcoming previous limitations by fabricating a simple device with valuable benefits such as flexibility, biocompatibility, disposability, biodegradability, easy operation, large surface-to-volume ratio, and cost-effectiveness. Depending on the performance type, the device can be used to analyze the analyte in the liquid or vapor phase. For liquid samples, various structures (including a dipstick, as well as microfluidic and lateral flow) have been constructed. Paper-based 3D sensors are prepared by gluing and folding different layers of a piece of paper, being more user-friendly, due to the combination of several preparation methods, the integration of different sensor elements, and the connection between two methods of detection in a small set. Paper sensors can be used in chromatographic, electrochemical, and colorimetric processes, depending on the type of transducer. Additionally, in recent years, the applicability of these sensors has been investigated in various applications, such as food and water quality, environmental monitoring, disease diagnosis, and medical sciences. Here, we review the development (from 2010 to 2021) of paper methods in the field of the detection and determination of toxic substances.

Nanomaterial application in bio/sensors for the detection of infectious diseases

Infectious diseases are a potential risk for public health and the global economy. Fast and accurate detection of the pathogens that cause these infections is important to avoid the transmission of the diseases. Conventional methods for the detection of these microorganisms are time-consuming, costly, and not applicable for on-site monitoring. Biosensors can provide a fast, reliable, and point of care diagnostic. Nanomaterials, due to their outstanding electrical, chemical, and optical features, have become key players in the area of biosensors. This review will cover different nanomaterials that employed in electrochemical, optical, and instrumental biosensors for infectious disease diagnosis and how these contributed to enhancing the sensitivity and rapidity of the various sensing platforms. Examples of nanomaterial synthesis methods as well as a comprehensive description of their properties are explained. Moreover, when available, comparative data, in the presence and absence of the nanomaterials, have been reported to further highlight how the usage of nanomaterials enhances the performances of the sensor.

Photochemical Synthesis of Gold and Silver Nanoparticles-A Review

Nanomaterials have supported important technological advances due to their unique properties and their applicability in various fields, such as biomedicine, catalysis, environment, energy, and electronics. This has triggered a tremendous increase in their demand. In turn, materials scientists have sought facile methods to produce nanomaterials of desired features, i.e., morphology, composition, colloidal stability, and surface chemistry, as these determine the targeted application. The advent of photoprocesses has enabled the easy, fast, scalable, and cost- and energy-effective production of metallic nanoparticles of controlled properties without the use of harmful reagents or sophisticated equipment. Herein, we overview the synthesis of gold and silver nanoparticles via photochemical routes. We extensively discuss the effect of varying the experimental parameters, such as the pH, exposure time, and source of irradiation, the use or not of reductants and surfactants, reagents' nature and concentration, on the outcomes of these noble nanoparticles, namely, their size, shape, and colloidal stability. The hypothetical mechanisms that govern these green processes are discussed whenever available. Finally, we mention their applications and insights for future developments.

Bimetallic Nanocrystals: Structure, Controllable Synthesis and Applications in Catalysis, Energy and Sensing

In recent years, bimetallic nanocrystals have attracted great interest from many researchers. Bimetallic nanocrystals are expected to exhibit improved physical and chemical properties due to the synergistic effect between the two metals, not just a combination of two monometallic properties. More importantly, the properties of bimetallic nanocrystals are significantly affected by their morphology, structure, and atomic arrangement. Reasonable regulation of these parameters of nanocrystals can effectively control their properties and enhance their practicality in a given application. This review summarizes some recent research progress in the controlled synthesis of shape, composition and structure, as well as some important applications of bimetallic nanocrystals. We first give a brief introduction to the development of bimetals, followed by the architectural diversity of bimetallic nanocrystals. The most commonly used and typical synthesis methods are also summarized, and the possible morphologies under different conditions are also discussed. Finally, we discuss the composition-dependent and shape-dependent properties of bimetals in terms of highlighting applications such as catalysis, energy conversion, gas sensing and bio-detection applications.