Fluidity-Guided Assembly of Au@Pt on Liposomes as a Catalase-Powered Nanomotor for Effective Cell Uptake in Cancer Cells and Plant Leaves

Molecular Dynamics Simulations Reveal Octanoylated Hyaluronic Acid Enhances Liposome Stability, Stealth and Targeting

Liposome-based drug delivery systems have been widely used in drug and gene delivery. However, issues such as instability, immune clearance, and poor targeting have significantly limited their clinical utility. Consequently, there is an urgent need for innovative strategies to improve liposome performance. In this study, we explore the interaction mechanisms of hyaluronic acid (HA), a linear anionic polysaccharide composed of repeating disaccharide units of d-glucuronic acid and N-acetyl-d-glucosamine connected by alternating β-1,3 and β-1,4 glycosidic linkages, and its octanoylated derivates (OHA) with liposomes using extensive coarse-grained molecular dynamics simulations. The octyl moieties of OHA spontaneously inserted into the phospholipid bilayer of liposomes, leading to their effective coating onto the surface of liposome and enhancing their structural stability. Furthermore, encapsulating liposome with OHA neutralized their surface potential, interfering with the formation of a protein corona known to contribute to liposomal immune clearance. Importantly, the encapsulated OHA maintained its selectivity and therefore targeting ability for CD44, which is often overexpressed in tumor cells. These molecular-scale findings shed light on the interaction mechanisms between HA and liposomes and will be useful for the development of next-generation liposome-based drug delivery systems.

Micro/Nanomotor-Driven Intelligent Targeted Delivery Systems: Dynamics Sources and Frontier Applications

Micro/nanomotors represent a promising class of drug delivery carriers capable of converting surrounding chemical or external energy into mechanical power, enabling autonomous movement. Their distinct autonomous propulsive force distinguishes them from other carriers, offering significant potential for enhancing drug penetration across cellular and tissue barriers. A comprehensive understanding of micro/nanomotor dynamics with various power sources is crucial to facilitate their transition from proof-of-concept to clinical application. In this review, micro/nanomotors are categorized into three classes based on their energy sources: endogenously stimulated, exogenously stimulated, and live cell-driven. The review summarizes the mechanisms governing micro/nanomotor movements under these energy sources and explores factors influencing autonomous motion. Furthermore, it discusses methods for controlling micro/nanomotor movement, encompassing aspects related to their structure, composition, and environmental factors. The remarkable propulsive force exhibited by micro/nanomotors makes them valuable for significant biomedical applications, including tumor therapy, bio-detection, bacterial infection therapy, inflammation therapy, gastrointestinal disease therapy, and environmental remediation. Finally, the review addresses the challenges and prospects for the application of micro/nanomotors. Overall, this review emphasizes the transformative potential of micro/nanomotors in overcoming biological barriers and enhancing therapeutic efficacy, highlighting their promising clinical applications across various biomedical fields.

Thermal accelerated urease-driven hyaluronan-targeted melanin nano-missile for bio-radar detection and chemodrug-free phototherapy

Polymer-based nanomotors are attracting increasing interest in the biomedical field due to their microscopic size and kinematic properties which support overcoming biological barriers, completing cellular uptake and targeted blasting in limited spaces. However, their applications are limited by the complex viscous physiological environment and lack of sufficient biocompatibility. This manuscript firstly reports a natural melanin nano-missile of MNP@HA-EDA@Urease@AIE PS (MHUA) based on photothermally accelerated urease-driven to achieve chemodrug-free phototherapy. Compared to conventional nano-missiles that only provide driving force, this photothermally accelerated urease-driven nanomotor is independent of chemodrug to maximise biocompatibility, and achieve ideal therapeutic effect through targeted PTT/PDT. In particular, the thermal effect can not only boost the catalytic activity of urease but also achieve ideally anti-tumor effect. In addition, guided by and AIE PS, the nanomotor can generate 1O2 to achieve PDT and be traced in real time serving as an effective fluorescent bio-radar for intracellular self-reporting during cancer treatment. Finally, the targeting ability of MUHA is provided by hyaluronan. Taken together, this MHUA platform provides a simple and effective strategy for target/fluorescence radar detective-guided PTT/PDT combination, and achieves good therapeutic results without chemodrug under thermal accelerated strategy, providing a new idea for the construction of chemodrug-free nanomotor-therapy system.

Engineered platelet cell motors for boosted cancer radiosensitization

Design of engineered cells to target and deliver nanodrugs to the hard-to-reach regions has become an exciting research area. However, the limited penetration and retention of cell-based carriers in tumor tissue restricted their therapeutic efficiency. Inspired by the enhanced delivery behavior of mobile micro/nanomotors, herein, urease-powered platelet cell motors (PLT@Au@Urease) capable of active locomotion, tumor targeting, and radiosensitizers delivery were designed for boosting radiosensitization. The engineered platelet cell motors were constructed by in situ synthesis and loading of radiosensitizers gold nanoparticles in platelets, and then conjugation with urease as the engine. Under physiological concentration of urea, thrust around PLT@Au@Urease motors can be generated via the biocatalytic reactions of urease, leading to rapid tumor cell targeting and enhanced cellular uptake of radiosensitizers. Encouragingly, in comparison with engineered PLT without propulsion capability (PLT@Au), the self-propelled PLT@Au@Urease motors could significantly increase intracellular ROS level and exacerbate nuclear DNA damage induced by γ-radiation, resulting in a remarkably high sensitization enhancement rate (1.89) than that of PLT@Au (1.08). In vivo experiments with 4 T1-bearing mice demonstrated that PLT@Au@Urease in combination with radiation therapy possessed good antitumor performance. Such an intelligent cell motor would provide a promising approach to enhance radiosensitization and broaden the applications of cell motor-based delivery systems.

In situ SERS imaging of protein-specific glycan oxidation on living cells to quantitatively visualize pathogen-cell interactions

Glycan oxidation on the cell surface occurs in many specific life processes including pathogen-cell interactions. This work develops a surface-enhanced Raman scattering (SERS) imaging strategy for in situ quantitative monitoring of protein-specific glycan oxidation mediated pathogen-cell interactions by utilizing Raman reporter DTNB and aptamer co-assembled platinum shelled gold nanoparticles (Au@Pt-DTNB/Apt). Using Fusarium graminearum (FG) and MCF-7 cells as models, Au@Pt-DTNB/Apt can specifically bind to MUC1 protein on the cell surface containing heavy galactose (Gal) and N-acetylgalactosamine (GalNAc) modification. When FG interacts with cells, the secreted galactose oxidase (GO) can oxidize Gal/GalNAc, and the generated reactive oxygen species (ROS) further oxidizes DTNB to produce TNB for greatly enhancing the SERS signal. This strategy can quantitatively visualize for the first time both the protein-specific glycan oxidation and the mediated pathogen-cell interactions, thus providing key quantitative information to distinguish and explore the pathogen-resistance and pharmacological mechanisms of different drugs.

Au/Pt@ZIF-90 Nanoenzyme Capsule-Based "Explosive" Signal Amplifier for "All-in-Tube" POCT

The sensitive, convenient, and visual detection of low-concentration disease markers in biological samples has always been a priority in disease diagnosis. However, existing research has been problematic due to complex operation and unsatisfactory sensitivity. Consequently, an "explosive" signal amplification platform based on Au/Pt@ZIF-90 was developed for sensitive visual detection of disease markers. In this study, a controllable and explosively released Au/Pt nanoparticles (NPs) "nanoenzyme capsule" was prepared by encapsulating Au/Pt NPs with excellent peroxidase activity in ZIF-90. This was achieved by adjusting the particle size of ZIF-90 and the encapsulation amount of Au/Pt NPs. Using the prepared capsules as the signal output module and aptamer as the target recognition module, an "All-in-Tube" portable point-of-care (POC) platform was constructed by integrating the Au/Pt@ZIF-90/filter paper and TMB/strips into an Eppendorf (EP) tube. By utilizing specific competitive binding of targets to aptamers, the platform enabled the sensitive and convenient measurement of small molecular disease markers. Taking adenosine as the proof of concept, the portable detection achieved excellent sensitivity. Moreover, the platform can achieve universal detection of various targets by varying the aptamer sequence. This signal amplification strategy provides a design pattern for the detection of low-concentration targets in biological samples and holds significant potential in the fields of disease diagnosis and environmental monitoring.

3D Motion Manipulation for Micro- and Nanomachines: Progress and Future Directions

In the past decade, micro- and nanomachines (MNMs) have made outstanding achievements in the fields of targeted drug delivery, tumor therapy, microsurgery, biological detection, and environmental monitoring and remediation. Researchers have made significant efforts to accelerate the rapid development of MNMs capable of moving through fluids by means of different energy sources (chemical reactions, ultrasound, light, electricity, magnetism, heat, or their combinations). However, the motion of MNMs is primarily investigated in confined two-dimensional (2D) horizontal setups. Furthermore, three-dimensional (3D) motion control remains challenging, especially for vertical movement and control, significantly limiting its potential applications in cargo transportation, environmental remediation, and biotherapy. Hence, an urgent need is to develop MNMs that can overcome self-gravity and controllably move in 3D spaces. This review delves into the latest progress made in MNMs with 3D motion capabilities under different manipulation approaches, discusses the underlying motion mechanisms, explores potential design concepts inspired by nature for controllable 3D motion in MNMs, and presents the available 3D observation and tracking systems.

Light-driven micro/nanomotors in biomedical applications

Nanotechnology brings hope for targeted drug delivery. However, most current drug delivery systems use passive delivery strategies with limited therapeutic efficiency. Over the past two decades, research on micro/nanomotors (MNMs) has flourished in the biomedical field. Compared with other driven methods, light-driven MNMs have the advantages of being reversible, simple to control, clean, and efficient. Under light irradiation, the MNMs can overcome several barriers in the body and show great potential in the treatment of various diseases, such as tumors, and gastrointestinal, cardiovascular and cerebrovascular diseases. Herein, the classification and mechanism of light-driven MNMs are introduced briefly. Subsequently, the applications of light-driven MNMs in overcoming physiological and pathological barriers in the past five years are highlighted. Finally, the future prospects and challenges of light-driven MNMs are discussed as well. This review will provide inspiration and direction for light-driven MNMs to overcome biological barriers in vivo and promote the clinical application of light-driven MNMs in the biomedical field.

Signal Amplification Strategy Design in Nanozyme-Based Biosensors for Highly Sensitive Detection of Trace Biomarkers

Nanozymes show great promise in enhancing disease biomarker sensing by leveraging their physicochemical properties and enzymatic activities. These qualities facilitate signal amplification and matrix effects reduction, thus boosting biomarker sensing performance. In this review, recent studies from the last five years, concentrating on disease biomarker detection improvement through nanozyme-based biosensing are examined. This enhancement primarily involves the modulations of the size, morphology, doping, modification, electromagnetic mechanisms, electron conduction efficiency, and surface plasmon resonance effects of nanozymes for increased sensitivity. In addition, a comprehensive description of the synthesis and tuning strategies employed for nanozymes has been provided. This includes a detailed elucidation of their catalytic mechanisms in alignment with the fundamental principles of enhanced sensing technology, accompanied by the presentation of quantitatively analyzed results. Moreover, the diverse applications of nanozymes in strip sensing, colorimetric sensing, electrochemical sensing, and surface-enhanced Raman scattering have been outlined. Additionally, the limitations, challenges, and corresponding recommendations concerning the application of nanozymes in biosensing have been summarized. Furthermore, insights have been offered into the future development and outlook of nanozymes for biosensing. This review aims to serve not only as a reference for enhancing the sensitivity of nanozyme-based biosensors but also as a catalyst for exploring nanozyme properties and their broader applications in biosensing.

Polysaccharide hydrogel platforms as suitable carriers of liposomes and extracellular vesicles for dermal applications

Lipid-based nanocarriers have been extensively investigated for their application in drug delivery. Particularly, liposomes are now clinically established for treating various diseases such as fungal infections. In contrast, extracellular vesicles (EVs) - small cell-derived nanoparticles involved in cellular communication - have just recently sparked interest as drug carriers but their development is still at the preclinical level. To drive this development further, the methods and technologies exploited in the context of liposome research should be applied in the domain of EVs to facilitate and accelerate their clinical translation. One of the crucial steps for EV-based therapeutics is designing them as proper dosage forms for specific applications. This review offers a comprehensive overview of state-of-the-art polysaccharide-based hydrogel platforms designed for artificial and natural vesicles with application in drug delivery to the skin. We discuss their various physicochemical and biological properties and try to create a sound basis for the optimization of EV-embedded hydrogels as versatile therapeutic avenues.

Mn-MOF catalyzed multi-site atom transfer radical polymerization electrochemical sensing of miRNA-21

A green electrochemical biosensor was developed based on metal-organic framework (MOF)-catalyzed atom transfer radical polymerization (ATRP) for quantifying miRNA-21, used as the proof-of-concept analyte. Unlike conventional ATRP, Mn-PCN-222 (PCN, porous coordination network) could be used as an alternative for green catalyst to substitute traditional catalysts. First, poly (diallyldimethylammonium chloride) (PDDA) was fixed on the surface of the indium tin oxide (ITO) electrode, and then the Mn-PCN-222 was linked to ITO electrode via electrostatic binding with PDDA. Next, aminated ssDNA (NH₂-DNA) was used to modify the electrode further by amide reaction with Mn-PCN-222. Then, the recognition and hybridization of NH₂-DNA with miRNA-21 prompt the generation of DNA-RNA complexes, which further hybridize with Fc-DNA@β-CD-Br₁₅ and permit the initiator to be immobilized on the electrode surface. Accordingly, β-CD-Br₁₅ could initiate the polymerization of ferrocenylmethyl methacrylates (FcMMA) under the catalysis of MOF to complete the ATRP reaction. FcMMA presented a distinct electrochemical signal at ~ 0.33 V. Taking advantage of the unique multi-site properties of β-CD-Br₁₅ and the efficient catalytic reaction induced by Mn-PCN-222, ultrasensitive detection of miRNA-21 was achieved with a detection limit of 0.4 fM. The proposed electrochemical biosensor has been applied to the detection of miRNA-21 in serum samples. Therefore, the proposed strategy exhibited potential in early clinical biomedicine.

Enzyme-Free Liposome Active Motion via Asymmetrical Lipid Efflux

As a class of biocompatible, water-dispersed colloids, liposomes have found widespread applications ranging from food to drug delivery. Adding mobility to these colloids, i.e., liposome micromotors, represents an attractive approach to next-generation liposome carriers with enhanced functionality and effectiveness. Currently, it remains unclear as to the scope of material features useful for building liposome micromotors or how they may differ functionally from their inorganic/polymer counterparts. In this work, we demonstrate liposome active motion taking advantage of mainly a pair of intrinsic material properties associated with these assemblies: lipid phase separation and extraction. We show that global phase separation of ternary lipid systems (such as DPPC/DOPC/cholesterol) within individual liposomes yields stable Janus particles with two distinctive liquid domains. While these anisotropic liposomes undergo pure Brownian diffusion in water, similar to their homogeneous analogues, adding extracting agents, cyclodextrins, to the system triggers asymmetrical cholesterol efflux about the liposomes, setting the latter into active motion. We present detailed analyses of liposome movement and cholesterol extraction kinetics to establish their correlation. We explore various experimental parameters as well as mechanistic details to account for such motion. Our results highlight the rich possibility to hierarchically design lipid-based artificial motors, from individual lipids, to their organization, surface chemistry, and interfacial mechanics.