ZIF-8 Microswimmers Self-Fast Dynamic Destruction in Microliter Volumes of Cerebrospinal Fluid Samples: Toward a Selective Assessment of Amyloidosis.

Herein, we describe the synthesis of magnetic zeolitic imidazole framework (ZIF-8) microswimmers for detecting and quantifying the amyloid beta (Aβ) peptide in cerebrospinal fluid (CSF) samples, which are used as a biomarker of amyloidosis for diagnosing Alzheimer's disease (AD). The microswimmers are prepared by external decoration of the ZIF-8 with magnetic FeO nanoparticles, followed by post internal encapsulation of quinine as fluorescent probe. The magnetic and surface properties of the microswimmers are fine-tuned to obtain tailored structures with an inner porous structure with the loaded fluorescent probe and outer magnetic engines.

Algae-MOF Biohybrid Microrobots for Rapid and Efficient On-The-Fly Degradation of Chemical Warfare Agents.

Active matter systems have emerged as powerful tools for enhancing chemical processes, with significant potential in environmental remediation. This study introduces a biohybrid algae microrobot covalently functionalized with catalytic UiO-66-NH zirconium-based metal-organic framework (Zr-MOF) nanoparticles for the rapid and efficient "on-the-fly" hydrolysis of toxic organophosphorus chemical warfare agents (CWA) simulants. Such algae-MOF biohybrid microrobots achieve highly efficient degradation of CWA simulants by overcoming the limitations of conventional diffusion-limited processes.

Technology Roadmap of Micro/Nanorobots.

Inspired by Richard Feynman's 1959 lecture and the 1966 film , the field of micro/nanorobots has evolved from science fiction to reality, with significant advancements in biomedical and environmental applications. Despite the rapid progress, the deployment of functional micro/nanorobots remains limited. This review of the technology roadmap identifies key challenges hindering their widespread use, focusing on propulsion mechanisms, fundamental theoretical aspects, collective behavior, material design, and embodied intelligence.

Cyclo-Octasulfur Crystals as Light-Controlled Molecular Muscles.

Here, we describe the synthesis and photo-responsive properties of 2D cyclo-octasulfur microcrystals (α-S8 MCs), produced using a quick, simple, cost-effective, and environmentally friendly hydrothermal method. Controlled 385-nm irradiation of these crystals induces an immediate, reversible, and sustained bending effect. The time required for the crystals to return to their initial shape is significantly reduced when exposed to 475-nm light, completing the entire excitation-relaxation cycle in less than 2 s.

Micromotors Meet Collective (Bio)sensing: The Asset Behind the Assay.

Micromotors are microscale devices with enormous potential for analytical (bio)sensing due to autonomous motion capabilities in extremely small sample volumes or for guided detection in localized hard-to-reach areas. These unique features enable dynamic interactions with the analytes, offering considerable promise in microscale environments and opening new avenues for on-the-fly (bio)sensing strategies. By selecting and discussing the ideas and findings behind pioneering works, we offer our perspective on the current state of the art in the field of (bio)sensing approaches based on the micromotors classified according to their detection principle: motion-based, optical, and electrochemical sensing.

Enhancing Polyphenol Delivery and Efficacy Using Functionalized Gold Nanoparticles: Antioxidant and Antibacterial Properties.

Research into the use of nanoparticles to enhance the delivery and efficacy of polyphenols is a topic of growing interest in the fields of nanotechnology, pharmacology and food science. Nanoparticles, due to their small size and high surface area, can improve the stability, solubility and bioavailability of polyphenols. Combining polyphenols with other bioactive compounds within nanoparticles can create synergistic effects, enhancing their overall therapeutic potential.

Self-Disassembling Macroporous Metal-Organic Framework-Based Micromotors with Magnetically Controlled Motion for Sequential Drug Release.

Herein, the synthesis of macroporous zeolitic imidazole framework (ZIF)-based magnetic micromotors (MMs) for the dual encapsulation of 5-fluorouracil (5-FU) and doxorubicin (DOX), with pH-triggered release is described. The MMs are synthesized in methanolic solutions, using superparamagnetic iron oxide nanoparticles (Fe₃O₄) as seeding agents and magnetic engines. The macroporous structure facilitates the loading of high doses of 5-FU, while DOX is docked on the surface of the MMs.

3D-Printed Dual-Channel Flow-Through Miniaturized Devices with Dual In-Channel Electrochemical Detection.

Here, we present three-dimensional-printed dual-channel flow-through miniaturized devices (3D) with dual electrochemical detection (ED) integrating two working electrodes each in an in-channel configuration (3D-ED). Prussian Blue (PB) shell-gold nanoparticles ((PB)AuNP) core-based electrochemistry was chosen for selective hydrogen peroxide determination. 3D-ED devices exhibited impress stability, identical intrachannel and interchannel electrochemical performances, and excellent interdevice precision with values under 9%, revealing the reliability of the design and fabrication of the devices.

Active Quantum Biomaterials-Enhanced Microrobots for Food Safety.

Timely disruptive tools for the detection of pathogens in foods are needed to face global health and economic challenges. Herein, the utilization of quantum biomaterials-enhanced microrobots (QBEMRs) as autonomous mobile sensors designed for the precise detection of endotoxins originating from Salmonella enterica (S. enterica) as an indicator species for food-borne contamination globally is presented.

Photophoretic MoS-FeO Piranha Micromotors for Collective Dynamic Microplastics Removal.

Microplastics are highly persistent emerging pollutants that are widely distributed in the environment. We report the use of MoS@FeO core-shell micromotors prepared by a hydrothermal approach to explore the degradation of plastic microparticles. Polystyrene was chosen as the model plastic due to its wide distribution and resistance to degradation using current approaches.

A dual colorimetric-electrochemical microfluidic paper-based analytical device for point-of-care testing of ischemic strokes.

A novel microfluidic paper-based analytical device with dual colorimetric and electrochemical detection (dual μPAD) was developed for the assessment of transferrin saturation (TSAT) in samples from ischemic stroke patients. TSAT was calculated from the ratio between transferrin-bound iron, which was colorimetrically measured, and the total iron-binding capacity, which was electrochemically measured. To this end, a μPAD was smartly designed, which integrated both colorimetric and electrochemical detection reservoirs, communicating a microchannel acting as a chemical reactor, and with preloading/storing capabilities (reagent-free device).

Molecular Memory Micromotors for Fast Snake Venom Toxin Dynamic Detection.

The analysis and detection of snake venom toxins are a matter of great importance in clinical diagnosis for fast treatment and the discovery of new pharmaceutical products. Current detection methods have high associated costs and require the use of sophisticated bioreceptors, which in some cases are difficult to obtain. Herein, we report the synthesis of template-based molecularly imprinted micromotors for dynamic detection of α-bungarotoxin as a model toxin present in the venom of many-banded krait ().

Spark-Discharge-Activated 3D-Printed Electrochemical Sensors.

3D printing technology is a tremendously powerful technology to fabricate electrochemical sensing devices. However, current conductive filaments are not aimed at electrochemical applications and therefore require intense activation protocols to unleash a suitable electrochemical performance. Current activation methods based on (electro)chemical activation (using strong alkaline solutions and organic solvents and/or electrochemical treatments) or combined approaches are time-consuming and require hazardous chemicals and dedicated operator intervention.

Laser-induced 2D/0D graphene-nanoceria freestanding paper-based films for on-site hydrogen peroxide monitoring in no-touch disinfection treatments.

A one-shot CO laser-based strategy to generate conductive reduced graphene oxide (rGO) decorated with nanoceria (nCe) is proposed. The 2D/0D rGO-nCe films, integrated as catalytic sensing layers in paper-based sensors, were employed for on-site monitoring of indoor fogging treatments against Listeria monocytogenes (Lm), a ubiquitous pathogenic bacterium. The rGO-nCe laser-assisted synthesis was optimized to preserve the rGO film morphological and electron-transfer features and simultaneously integrate catalytic nCe.

Gold Nanoparticle-Decorated Catalytic Micromotor-Based Aptassay for Rapid Electrochemical Label-Free Amyloid-β42 Oligomer Determination in Clinical Samples from Alzheimer's Patients.

Micromotor (MM) technology offers a valuable and smart on-the-move biosensing microscale approach in clinical settings where sample availability is scarce in the case of Alzheimer's disease (AD). Soluble amyloid-β protein oligomers (AβO) (mainly AβO) that circulate in biological fluids have been recognized as a molecular biomarker and therapeutic target of AD due to their high toxicity, and they are correlated much more strongly with AD compared to the insoluble Aβ monomers. A graphene oxide (GO)-gold nanoparticles (AuNPs)/nickel (Ni)/platinum nanoparticles (PtNPs) micromotors (MM)-based electrochemical label-free aptassay is proposed for sensitive, accurate, and rapid determination of AβO in complex clinical samples such as brain tissue, cerebrospinal fluid (CSF), and plasma from AD patients.

Micromotor-based electrochemical immunoassays for reliable determination of amyloid-β (1-42) in Alzheimer's diagnosed clinical samples.

Alzheimer's disease (AD), in addition to being the most common cause of dementia, is very difficult to diagnose, with the 42-amino acid form of Aβ (Aβ-42) being one of the main biomarkers used for this purpose. Despite the enormous efforts made in recent years, the technologies available to determine Aβ-42 in human samples require sophisticated instrumentation, present high complexity, are sample and time-consuming, and are costly, highlighting the urgent need not only to develop new tools to overcome these limitations but to provide an early detection and treatment window for AD, which is a top-challenge. In recent years, micromotor (MM) technology has proven to add a new dimension to clinical biosensing, enabling ultrasensitive detections in short times and microscale environments.

Print-Pause-Print Fabrication of Tailored Electrochemical Microfluidic Devices.

Three-dimensional (3D) printing technology has emerged as a powerful technology for the fabrication of low-cost microfluidics. Nevertheless, the fabrication of microfluidic devices integrating high-performance electrochemical sensors in practical applications is still an open challenge. Although automatic fabrication of the microfluidic device and the electrodes can be successfully carried out using a one-step multimaterial fused filament fabrication (FFF) approach, the as-printed electrochemical performance of these electrodes is not good enough for chemical (bio)sensing and their surface modification is challenging because after closing the channel there is no physical access to the electrode.

Photoactive Au@MoS Micromotors for Dynamic Surface-Enhanced Raman Spectroscopy Sensing.

Photophoretic Au@MoS micromotors are used as smart mobile substrates for dynamic surface-enhanced Raman spectroscopy (SERS) sensing. The photophoretic capabilities and swarming-like propulsion of the micromotors allow for their schooling and accumulation in the measuring spot, increasing the density of SERS-active gold nanoparticles for Raman mapping and, simultaneously, the preconcentration of the target analyte. The generation of "hot-microflake spots" directly in the Raman irradiation point results in a 15-18-fold enhancement in the detection of crystal violet without the requirement for additional external sources for propulsion.

Magnetic Janus micromotors for fluorescence biosensing of tacrolimus in oral fluids.

Tacrolimus (FK506) is a macrolide lactone immunosuppressive drug that is commonly used in transplanted patients to avoid organ rejection. FK506 exhibits high inter- and intra-patient pharmacokinetic variability, making monitoring necessary for organ graft survival. This work describes the development of a novel bioassay for monitoring FK506.

The rise of metal-organic framework based micromotors.

Micromotors (MMs) are micro and nanoscale devices capable of converting energy into autonomous motion. Metal-organic frameworks (MOFs) are crystalline materials that display exceptional properties such as high porosity, internal surface areas, and high biocompatibility. As such, MOFs have been used as active materials or building blocks for MMs.

Paper-Based Analytical Devices for Accurate Assessment of Transferrin Saturation in Diagnosed Clinical Samples from Ischemic Stroke Patients.

For the first time, a paper-based analytical device (PAD) was developed for the assessment of transferrin saturation (TSAT), which is defined as the ratio between iron bound to transferrin (Tf) and the total iron-binding capacity (TIBC) of Tf. Both parameters were simultaneously measured on the same PAD using ferrozine as a chromophore and a smartphone as the color reader. To this end, Tf was first isolated from serum using anti-Tf immunomagnetic beads to ensure that only the Tf-bound iron was measured, improving the selectivity and accuracy of TSAT assessment.

Photoresponsive MoS and WS microflakes as mobile biocide agents.

A fuel-free strategy for the eradication of and biofilms using WS and MoS photophoretic microflakes is described. The microflakes were prepared by liquid-phase exfoliation of the materials. Under electromagnetic irradiation at 480 or 535 nm, the microflakes experience a fast collective behavior at speeds of over 300 μm s due to photophoresis.

Analysis of microsamples by miniaturized magnetic-based pipette tip microextraction: determination of free cortisol in serum and urine from very low birth weight preterm newborns.

Miniaturized magnetic-based pipette tip microextraction is presented as a sample preparation approach for microsamples. It involves quick dispersion of a diminutive amount of a magnetic sorbent material in a low-volume sample (10 μL) to entrap the target analytes. Next, the dispersion is aspirated using a (semi)automatic pipette through a pipette tip with a small cubic neodymium magnet inside, which retrieves the magnetic sorbent containing the analytes.