Enzyme-coated Janus nanoparticles that selectively bind cell receptors as a function of the concentration of glucose

A Biomolecular Toolbox for Precision Nanomotors

The application of nanomotors for cancer diagnosis and therapy is a new and exciting area of research, which when combined with precision nanomedicine, promises to solve many of the issues encountered by previous development of passive nanoparticles. The goal of this article is to introduce nanomotor and nanomedicine researchers to the deep pool of knowledge available regarding cancer cell biology and biochemistry, as well as provide a greater appreciation of the complexity of cell membrane compositions, extracellular surfaces, and their functional consequences. A short description of the nanomotor state-of-art for cancer therapy and diagnosis is first provided, as well as recommendations for future directions of the field. Then, a biomolecular targeting toolbox has been collated for researchers looking to apply their nanomaterial of choice to a biological setting, as well as providing a glimpse into currently available clinical therapies and technologies. This toolbox contains an overview of different classes of targeting molecules available for high affinity and specific targeting and cell surface targets to aid researchers in the selection of a clinical disease model and targeting methodology. It is hoped that this review will provide biological context, inspiration, and direction to future nanomotor and nanomedicine research.

Development of Janus Particles as Potential Drug Delivery Systems for Diabetes Treatment and Antimicrobial Applications

Janus particles have emerged as a novel and smart material that could improve pharmaceutical formulation, drug delivery, and theranostics. Janus particles have two distinct compartments that differ in functionality, physicochemical properties, and morphological characteristics, among other conventional particles. Recently, Janus particles have attracted considerable attention as effective particulate drug delivery systems as they can accommodate two opposing pharmaceutical agents that can be engineered at the molecular level to achieve better target affinity, lower drug dosage to achieve a therapeutic effect, and controlled drug release with improved pharmacokinetics and pharmacodynamics. This article discusses the development of Janus particles for tailored and improved delivery of pharmaceutical agents for diabetes treatment and antimicrobial applications. It provides an account of advances in the synthesis of Janus particles from various materials using different approaches. It appraises Janus particles as a promising particulate system with the potential to improve conventional delivery systems, providing a better loading capacity and targeting specificity whilst promoting multi-drugs loading and single-dose-drug administration.

Enzyme-powered micro- and nano-motors: key parameters for an application-oriented design

Nature has inspired the creation of artificial micro- and nanomotors that self-propel converting chemical energy into mechanical action. These tiny machines have appeared as promising biomedical tools for treatment and diagnosis and have also been used for environmental, antimicrobial or sensing applications. Among the possible catalytic engines, enzymes have emerged as an alternative to inorganic catalysts due to their biocompatibility and the variety and bioavailability of fuels. Although the field of enzyme-powered micro- and nano-motors has a trajectory of more than a decade, a comprehensive framework on how to rationally design, control and optimize their motion is still missing. With this purpose, herein we performed a thorough bibliographic study on the key parameters governing the propulsion of these enzyme-powered devices, namely the chassis shape, the material composition, the motor size, the enzyme type, the method used to incorporate enzymes, the distribution of the product released, the motion mechanism, the motion media and the technique used for motion detection. In conclusion, from the library of options that each parameter offers there needs to be a rational selection and intelligent design of enzymatic motors based on the specific application envisioned.

Self-Propelled Micro/Nanomotors for Tumor Targeting Delivery and Therapy

Cancer is still one of the most serious diseases with threats to health and life. Although some advances have been made in targeting delivery of antitumor drugs over the past number of years, there are still many problems needing to be solved, such as poor efficacy and high systemic toxicity. Micro/nanomotors capable of self-propulsion in fluid provide promising platforms for improving the efficiency of tumor delivery. Herein, the recent progress in micro/nanomotors for tumor targeting delivery and therapy is reviewed, with special focus on the contributions of micro/nanomotors to the different stages of tumor targeting delivery as well as the combination therapy by micro/nanomotors. The present limitations and future directions are also put forward for further development.

Janus Magnetic-Plasmonic Nanoparticles for Magnetically Guided and Thermally Activated Cancer Therapy

Progress of thermal tumor therapies and their translation into clinical practice are limited by insufficient nanoparticle concentration to release therapeutic heating at the tumor site after systemic administration. Herein, the use of Janus magneto-plasmonic nanoparticles, made of gold nanostars and iron oxide nanospheres, as efficient therapeutic nanoheaters whose on-site delivery can be improved by magnetic targeting, is proposed. Single and combined magneto- and photo-thermal heating properties of Janus nanoparticles render them as compelling heating elements, depending on the nanoparticle dose, magnetic lobe size, and milieu conditions. In cancer cells, a much more effective effect is observed for photothermia compared to magnetic hyperthermia, while combination of the two modalities into a magneto-photothermal treatment results in a synergistic cytotoxic effect in vitro. The high potential of the Janus nanoparticles for magnetic guiding confirms them to be excellent nanostructures for in vivo magnetically enhanced photothermal therapy, leading to efficient tumor growth inhibition.

Self-Assembled Phage-Based Colloids for High Localized Enzymatic Activity

Catalytically active colloids are model systems for chemical motors and active matter. It is desirable to replace the inorganic catalysts and the toxic fuels that are often used with biocompatible enzymatic reactions. However, compared to inorganic catalysts, enzyme-coated colloids tend to exhibit less activity. Here, we show that the self-assembly of genetically engineered M13 bacteriophages that bind enzymes to magnetic beads ensures high and localized enzymatic activity. These phage-decorated colloids provide a proteinaceous environment for directed enzyme immobilization. The magnetic properties of the colloidal carrier particle permit repeated enzyme recovery from a reaction solution, while the enzymatic activity is retained. Moreover, localizing the phage-based construct with a magnetic field in a microcontainer allows the enzyme-phage-colloids to function as an enzymatic micropump, where the enzymatic reaction generates a fluid flow. This system shows the fastest fluid flow reported to date by a biocompatible enzymatic micropump. In addition, it is functional in complex media including blood, where the enzyme-driven micropump can be powered at the physiological blood-urea concentrations.

Multifunctional motion-to-color janus transducers for the rapid detection of sepsis biomarkers in whole blood

Self-propelled particles are revolutionizing sensing applications thanks to a unique motion-based signal generation mechanism in which biorecognition reactions are detected as changes in the velocity of the colloids. Here a new family of self-propelled multifunctional Janus particles is introduced that enables detecting changes in particle motion colorimetrically. The particles consist of an iron oxide core that provides color and magnetism, and a Janus coating that provides biospecific recognition and locomotive properties. In this approach, biomolecular interactions trigger changes in particle motion that are detected as variations in color when spotted on a piece of paper. These variations in color are then read and quantified with a custom-made smartphone app. The high surface area and magnetism of the particles makes them ideal building blocks for developing biosensors because they allow for the rapid capture of a target molecule and the removal of non-specific interactions. Biosensors engineered with the proposed multifunctional particles were able to detect the sepsis biomarker procalcitonin at clinically relevant concentrations within 13 min in whole blood, which is faster than other approaches requiring hour-long incubation steps under controlled conditions to detect the same biomarker in purified serum. The short assay time along with the point-of-need design makes these biosensors suitable for stratifying patients according to their sepsis risk level during triage independently of resource constraints.

Hybrid Janus Particles: Challenges and Opportunities for the Design of Active Functional Interfaces and Surfaces

Janus particles are a unique class of multifunctional patchy particles combining two dissimilar chemical or physical functionalities at their opposite sides. The asymmetry characteristic for Janus particles allows them to self-assemble into sophisticated structures and materials not attainable by their homogeneous counterparts. Significant breakthroughs have recently been made in the synthesis of Janus particles and the understanding of their assembly. Nevertheless, the advancement of their applications is still a challenging field. In this Review, we highlight recent developments in the use of Janus particles as building blocks for functional materials. We provide a brief introduction into the synthetic strategies for the fabrication of JPs and their properties and assembly, outlining the existing challenges. The focus of this Review is placed on the applications of Janus particles for active interfaces and surfaces. Active functional interfaces are created owing to the stabilization efficiency of Janus particles combined with their capability for interface structuring and functionalizing. Moreover, Janus particles can be employed as building blocks to fabricate active functional surfaces with controlled chemical and topographical heterogeneity. Ultimately, we will provide implications for the rational design of multifunctional materials based on Janus particles.

Janus nanoparticles in cancer diagnosis, therapy and theranostics

Anisotropic Janus nanoparticles (JNPs), due to their several distinct merits, have been widely investigated for cancer theranostics.

Tunable fabrication of folic acid-Au@poly(acrylic acid)/mesoporous calcium phosphate Janus nanoparticles for CT imaging and active-targeted chemotherapy of cancer cells

A novel, facile and reproducible method was explored to construct uniform folic acid-Au@poly(acrylic acid)/mesoporous calcium phosphate Janus nanoparticles (FA-Au@PAA/mCaP JNPs), which act as an efficient nanoplatform for X-ray computed tomography (CT) imaging and active-targeted chemotherapy in vitro.