Scalable fabrication of biohybrid magnetic MOF-based micromotors for toxin enrichment.

Contemporary industrial production and human activity release numerous toxins into our environment. Metal-organic frameworks (MOFs) are potential candidates for addressing these toxins due to their ultrahigh surface area, tailored pore size, and responsiveness to stimuli. With the rise of micro/nanomotor, imparting active motion to MOFs becomes crucial for efficiently performing tasks in challenging locations.

Quantitative Assessment of Bony Fish Tropomyosin Using a Monoclonal Antibody Competitive ELISA.

Bony fish is one of the big-nine allergenic foods in the US. This study established a monoclonal antibody (mAb)-based indirect competitive enzyme-linked immunosorbent assay (ELISA) for the detection of bony fish tropomyosin (TM), a fish allergen. Immunoassay (Western blot and ELISA) was performed to characterize anti-TM mAb8F5 (target configuration, immunoaffinity, and species selectivity).

MXenes for Wearable Physical Sensors toward Smart Healthcare.

The gradual rise of personal healthcare awareness is accelerating the deployment of wearable sensors, whose ability of acquiring physiological vital signs depends on sensing materials. MXenes have distinct chemical and physical superiorities over other 2D nanomaterials for wearable sensors. This review presents a comprehensive summary of the latest advancements in MXenes-based materials for wearable physical sensors.

Sensitive Colorimetric Lateral Flow Assays Enabled by Platinum-Group Metal Nanoparticles with Peroxidase-Like Activities.

The last several decades have witnessed the success and popularity of colorimetric lateral flow assay (CLFA) in point-of-care testing. Driven by increasing demand, great efforts have been directed toward enhancing the detection sensitivity of CLFA. Recently, platinum-group metal nanoparticles (PGM NPs) with peroxidase-like activities have emerged as a type of promising colorimetric labels for enhancing the sensitivity of CLFA.

Peroxidase mimics of platinum-group metals for diagnostics: opportunities and challenges.

Platinum-group metal (PGM) nanostructures with peroxidase-like catalytic activities (, peroxidase mimics) have been actively developed and applied to diagnostics in recent years. This article provides our viewpoints on this emerging field from the perspectives of materials science and solid-state chemistry angles. We start with an introduction to PGM peroxidase mimics, their catalytic efficiencies, and insights into catalysis from computational simulations.

On the role of wall thickness in determining the plasmonic properties of silver-gold nanocages.

This work examines the roles played by wall thickness in determining the plasmonic properties of gold-silver (Ag-Au) nanocages. Ag-Au cages with different wall thicknesses, but the same void or outer size, shape, and elemental composition, were designed as a model platform. The experimental findings were understood with theoretical calculations.

Catalytic Gold-Iridium Nanoparticles as Labels for Sensitive Colorimetric Lateral Flow Assay.

The colorimetric lateral flow assay (CLFA, also known as test strip) is a widely used point-of-care diagnostic technology. It has been a challenge to significantly improve the detection sensitivity of CLFA without involving additional equipment and/or compromising its simplicity. In this work, we break through the detection limit barrier of CLFA by developing a type of catalytic nanoparticles (NPs) used as labels.

Noble Metal Nanoparticles for Point-of-Care Testing: Recent Advancements and Social Impacts.

Point-of-care (POC) tests for the diagnosis of diseases are critical to the improvement of the standard of living, especially for resource-limited areas or countries. In recent years, nanobiosensors based on noble metal nanoparticles (NM NPs) have emerged as a class of effective and versatile POC testing technology. The unique features of NM NPs ensure great performance of associated POC nanobiosensors.

Rapid testing for coronavirus disease 2019 (COVID-19).

Rapid testing, generally refers to the paper-based diagnostic platform known as "lateral flow assay" (LFA), has emerged as a critical asset to the containment of coronavirus disease 2019 (COVID-19) around the world. LFA technology stands out amongst peer platforms due to its cost-effective design, user-friendly interface, and low sample-to-readout times. This article aims to introduce its design, use, and practicality for the purpose of diagnosing SARS-CoV-2 infection.

Morphology-Invariant Metallic Nanoparticles with Tunable Plasmonic Properties.

Current methods for tuning the plasmonic properties of metallic nanoparticles typically rely on alternating the morphology (i.e., size and/or shape) of nanoparticles.

Nickel-Platinum Nanoparticles as Peroxidase Mimics with a Record High Catalytic Efficiency.

While nanoscale mimics of peroxidase have been extensively developed over the past decade or so, their catalytic efficiency as a key parameter has not been substantially improved in recent years. Herein, we report a class of highly efficient peroxidase mimic-nickel-platinum nanoparticles (Ni-Pt NPs) that consist of nickel-rich cores and platinum-rich shells. The Ni-Pt NPs exhibit a record high catalytic efficiency with a catalytic constant () as high as 4.

Nanocrystals of platinum-group metals as peroxidase mimics for diagnostics.

Peroxidase mimics of nanoscale materials as alternatives to natural peroxidases have found widespread uses in biomedicine. Among various types of peroxidase mimics, platinum-group metal (PGM) nanocrystals have drawn considerable attention in recent years due to their superior properties. Particularly, PGM nanocrystals display high catalytic efficiencies, allow for facile surface modifications, and possess excellent stabilities.

Size Effect in Pd-Ir Core-Shell Nanoparticles as Nanozymes.

Comprehensive studies on the size effect in nanozyme (i. e., nanomaterials with enzyme-like activities)-based catalysis have rarely been reported.

Template Regeneration in Galvanic Replacement: A Route to Highly Diverse Hollow Nanostructures.

The ability to produce a diverse spectrum of hollow nanostructures is central to the advances in many current and emerging areas of technology. Herein, we report a general method to craft hollow nanostructures with highly tunable physical and chemical parameters. The key strategy is to regenerate the nanoscale sacrificial templates in a galvanic replacement reaction through site-selective overgrowth.

Strain Effect in Palladium Nanostructures as Nanozymes.

While various effects of physicochemical parameters (e.g., size, facet, composition, and internal structure) on the catalytic efficiency of nanozymes (i.

Enhancing the sensitivity of colorimetric lateral flow assay (CLFA) through signal amplification techniques.

Colorimetric lateral flow assay (CLFA) is one of a handful of diagnostic technologies that can be truly taken out of the laboratory for point-of-care testing without the need for any equipment and skilled personnel. Despite its simplicity and practicality, it remains a grand challenge to substantially enhance the detection sensitivity of CLFA without adding complexity. Such a limitation in sensitivity inhibits many critical applications such as early detection of significant cancers and severe infectious diseases.

Platinum-Decorated Gold Nanoparticles with Dual Functionalities for Ultrasensitive Colorimetric in Vitro Diagnostics.

Au nanoparticles (AuNPs) as signal reporters have been utilized in colorimetric in vitro diagnostics (IVDs) for decades. Nevertheless, it remains a grand challenge to substantially enhance the detection sensitivity of AuNP-based IVDs as confined by the inherent plasmonics of AuNPs. In this work, we circumvent this confinement by developing unique dual-functional AuNPs that were engineered by coating conventional AuNPs with ultrathin Pt skins of sub-10 atomic layers (i.

A non-enzyme cascade amplification strategy for colorimetric assay of disease biomarkers.

A non-enzyme cascade amplification strategy, based on the dissolution of Ag nanoparticles and a Pt nanocube-catalyzed reaction, for colorimetric assay of disease biomarkers was developed. This strategy overcomes the intrinsic limitations of enzymes involved in conventional enzymatic amplification techniques, thanks to the utilization of noble-metal nanostructures with superior properties.

Facile Colorimetric Detection of Silver Ions with Picomolar Sensitivity.

Although various colorimetric methods have been actively developed for the detection of Ag ions because of their simplicity and reliability, the limits of detection of these methods are confined to the nanomolar (nM) level. Here, we demonstrate a novel strategy for colorimetric Ag detection with picomolar (pM) sensitivity. This strategy involves the use of poly(vinylpyrrolidone)- (PVP-) capped Pt nanocubes as artificial peroxidases that can effectively generate a colored signal by catalyzing the oxidation of peroxidase substrates.

An Enzyme-Free Signal Amplification Technique for Ultrasensitive Colorimetric Assay of Disease Biomarkers.

Enzyme-based colorimetric assays have been widely used in research laboratories and clinical diagnosis for decades. Nevertheless, as constrained by the performance of enzymes, their detection sensitivity has not been substantially improved in recent years, which inhibits many critical applications such as early detection of cancers. In this work, we demonstrate an enzyme-free signal amplification technique, based on gold vesicles encapsulated with Pd-Ir nanoparticles as peroxidase mimics, for colorimetric assay of disease biomarkers with significantly enhanced sensitivity.

Seed-Mediated Growth of Colloidal Metal Nanocrystals.

Seed-mediated growth is a powerful and versatile approach for the synthesis of colloidal metal nanocrystals. The vast allure of this approach mainly stems from the staggering degree of control one can achieve over the size, shape, composition, and structure of nanocrystals. These parameters not only control the properties of nanocrystals but also determine their relevance to, and performance in, various applications.

Ru Nanoframes with an fcc Structure and Enhanced Catalytic Properties.

Noble-metal nanoframes are of great interest to many applications due to their unique open structures. Among various noble metals, Ru has never been made into nanoframes. In this study, we report for the first time an effective method based on seeded growth and chemical etching for the facile synthesis of Ru nanoframes with high purity.

Pd-Ir Core-Shell Nanocubes: A Type of Highly Efficient and Versatile Peroxidase Mimic.

Peroxidase mimics with dimensions on the nanoscale have received great interest as emerging artificial enzymes for biomedicine and environmental protection. While a variety of peroxidase mimics have been actively developed recently, limited progress has been made toward improving their catalytic efficiency. In this study, we report a type of highly efficient peroxidase mimic that was engineered by depositing Ir atoms as ultrathin skins (a few atomic layers) on Pd nanocubes (i.

Shape-Controlled Synthesis of Colloidal Metal Nanocrystals: Thermodynamic versus Kinetic Products.

This Perspective provides a contemporary understanding of the shape evolution of colloidal metal nanocrystals under thermodynamically and kinetically controlled conditions. It has been extremely challenging to investigate this subject in the setting of one-pot synthesis because both the type and number of seeds involved would be changed whenever the experimental conditions are altered, making it essentially impossible to draw conclusions when comparing the outcomes of two syntheses conducted under different conditions. Because of the uncertainty about seeds, most of the mechanistic insights reported in literature for one-pot syntheses of metal nanocrystals with different shapes are either incomplete or ambiguous, and some of them might be misleading or even wrong.

Facile synthesis of iridium nanocrystals with well-controlled facets using seed-mediated growth.

Iridium nanoparticles have only been reported with roughly spherical shapes and sizes of 1-5 nm, making it impossible to investigate their facet-dependent catalytic properties. Here we report for the first time a simple method based on seed-mediated growth for the facile synthesis of Ir nanocrystals with well-controlled facets. The essence of this approach is to coat an ultrathin conformal shell of Ir on a Pd seed with a well-defined shape at a relatively high temperature to ensure fast surface diffusion.