Biocatalytic Buoyancy‑Driven Nanobots for Autonomous Cell Recognition and Enrichment

Autonomously self-propelled nanoswimmers represent the nextgeneration nano-devices for bio-and environmental technology.However,current nanoswimmers generate limited energy output and can only move in short distances and duration,thus are struggling to be applied in practical challenges,such as living cell transportation.Here,we describe the construction of biodegradable metal-organic framework based nanobots with chemically driven buoyancy to achieve highly efficient,long-distance,directional vertical motion to“find-and-fetch”target cells.Nanobots surface-functionalized with antibodies against the cell surface marker carcinoembryonic antigen are exploited to impart the nanobots with specific cell targeting capacity to recognize and separate cancer cells.We demonstrate that the self-propelled motility of the nanobots can sufficiently transport the recognized cells autonomously,and the separated cells can be easily collected with a customized glass column,and finally regain their full metabolic potential after the separation.The utilization of nanobots with easy synthetic pathway shows considerable promise in cell recognition,separation,and enrichment.

On-chip structure-switching aptamer-modified magnetic nanobeads for the continuous monitoring of interferon-gamma ex vivo

Cytokines are cell signaling molecules that indicate the health status of the body.In this study,we developed a microfluidic device integrated with structure-switching aptamers capable of continuously tracking the concentration of the cytokine interferon gamma(IFN-γ)in cell culture medium and blood serum.First,a ferrocene(Fc)-labeled structure-switching signaling aptamer with a hairpin structure targeting IFN-γwas immobilized on magnetic nanobeads by the strongest noncovalent interactions between streptavidin and biotin.The aptamer-modified magnetic nanobeads were trapped on a customized microfluidic chip by a magnetic field to form the sensing interface.The binding of IFN-γcould trigger the hairpin structure of the aptamer to unfold,pushing Fc redox molecules away from the sensing interface and consequently switching off the electrochemical signal.The change in the redox current of Fc was quantitatively related to the concentration of IFN-γin a linear range of 10–500 pg mL^(−1)and with the lowest detection limit of 6 pgmL^(−1).This microfluidic device was specific to IFN-γin the presence of overabundant serum proteins and allowed the continuous monitoring of IFN-γwithout adding exogenous reagents.It provided a universal point-of-care biosensing platform for the real-time detection of a spectrum of analytes.

Inorganic/organic combination:Inorganic particles/polymer composites for tissue engineering applications

Biomaterials have ushered the field of tissue engineering and regeneration into a new era with the development of advanced composites.Among these,the composites of inorganic materials with organic polymers present unique structural and biochemical properties equivalent to naturally occurring hybrid systems such as bones,and thus are highly desired.The last decade has witnessed a steady increase in research on such systems with the focus being on mimicking the peculiar properties of inorganic/organic combination composites in nature.In this review,we discuss the recent progress on the use of inorganic particle/polymer composites for tissue engineering and regenerative medicine.We have elaborated the advantages of inorganic particle/polymer composites over their organic particle-based composite counterparts.As the inorganic particles play a crucial role in defining the features and regenerative capacity of such composites,the review puts a special emphasis on the various types of inorganic particles used in inorganic particle/polymer composites.The inorganic particles that are covered in this review are categorised into two broad types(1)solid(e.g.,calcium phosphate,hydroxyapatite,etc.)and(2)porous particles(e.g.,mesoporous silica,porous silicon etc.),which are elaborated in detail with recent examples.The review also covers other new types of inorganic material(e.g.,2D inorganic materials,clays,etc.)based polymer composites for tissue engineering applications.Lastly,we provide our expert analysis and opinion of the field focusing on the limitations of the currently used inorganic/organic combination composites and the immense potential of new generation of composites that are in development.

Alloyed nanostructures integrated metal-phenolic nanoplatform for synergistic wound disinfection and revascularization

New materials for combating bacteria-caused infection and promoting the formation of microvascular networks during wound healing are of vital importance.Although antibiotics can be used to prevent infection,treatments that can disinfect and accelerate wound healing are scarce.Herein,we engineer a coating that is both highly compatible with current wound dressing substrates and capable of simultaneously disinfecting and revascularizing wounds using a metal-phenolic nanoplatform containing an alloyed nanostructured architecture(Ag@Cu-MPNNC).The alloyed nanostructure is formed by the spontaneous co-reduction and catalytic disproportionation reaction of multiple metal ions on a foundation metal-phenolic supramolecular layer.This synergistic presence of metals greatly improves the antibacterial activity against both Gram-negative and Gram-positive pathogenic bacteria,while demonstrating negligible cytotoxicity to normal tissue.In infected rat models,the Ag@Cu-MPNNC could kill bacteria efficiently,promoting revascularization and accelerate wound closure with no adverse side effects in infected in vivo models.In other words,this material acts as a combination therapy by inhibiting bacterial invasion and modulating bio-nano interactions in the wound.

Super-assembly of integrated gold magnetic assay with loopmediated isothermal amplification for point-of-care testing

With the increasing global threat of various diseases and infections,it is essential to develop a fast,low-cost,and easy-to-use point-of-care testing(POCT)system for inspections at all levels of medical institutions and self-examination at home.In this work,gold magnetic nanoparticles(GMNPs)are used as the key material,and a rapid visual detection method is designed through integrating loop-mediated isothermal amplification(LAMP)and lateral flow assay(LFA)biosensor for detecting a variety of analytes which includes whole blood,buccal swabs,and DNA.It is worth to note that the proposed method does not need DNA extraction.Furthermore,uracil DNA glycosylase(UDG)is employed to eliminate carrier contamination for preventing false positive results.The whole detection process can be finished within 25 min.The accuracy of detection is measured by assessing the polymorphisms of the methylenetetrahydrofolate reductase(MTHFR)C677T.The detection limit of the newly developed extraction-free detection system for MTHFR C677T is 0.16 ng/μL.A preliminary clinical study of the proposed method is carried out by analyzing 600 clinical samples(including 200 whole blood samples,100 buccal swabs,and 300 genomic DNA samples).The results indicate that the proposed method is 100%consistent with the sequencing results which provides a new choice for POCT and shows a broad application prospect in all levels of medical clinics and at home.

Navigating micro- and nano-motors/swimmers with machine learning: Challenges and future directions

Micro-/nano-motors(MNMs)or swimmers are minuscule machines that can convert various forms of energy,such as chemical,electrical,or magnetic energy,into motion.These devices have attracted significant attention owing to their potential application in a wide range of fields such as drug delivery,sensing,and microfabrication.However,owing to their diverse shapes,sizes,and structural/chemical compositions,the development of MNMs faces several challenges,such as understanding their structure-function relationships,which is crucial for achieving precise control over their motion within complex environments.In recent years,machine learning techniques have shown promise in addressing these challenges and improving the performance of MNMs.Machine learning techniques can analyze large amounts of data,learn from patterns,and make predictions,thereby enabling MNMs to navigate complex environments,avoid obstacles,and perform tasks with higher efficiency and reliability.This review introduces the current state-of-the-art machine learning techniques in MNM research,with a particular focus on employing machine learning to understand and manipulate the navigation and locomotion of MNMs.Finally,we discuss the challenges and opportunities in this field and suggest future research directions.

Nature-inspired topographies on hydroxyapatite surfaces regulate stem cells behaviour

Surface topography is one of the key factors in regulating interactions between materials and cells.While topographies presented to cells in vivo are non-symmetrical and in complex shapes,current fabrication techniques are limited to replicate these complex geometries.In this study,we developed a microcasting technique and successfully produced imprinted hydroxyapatite(HAp)surfaces with nature-inspired(honeycomb,pillars,and isolated islands)topographies.The in vitro biological performance of the developed non-symmetrical topographies was evaluated using adipose-derived stem cells(ADSCs).We demonstrated that ADSCs cultured on all HAp surfaces,except honeycomb patterns,presented well-defined stress fibers and expressed focal adhesion protein(paxillin)molecules.Isolated islands topographies significantly promoted osteogenic differentiation of ADSCs with increased alkaline phosphatase activity and upregulation of key osteogenic markers,compared to the other topographies and the control unmodified(flat)HAp surface.In contrast,honeycomb topographies hampered the ability of the ADSCs to proliferate and differentiate to the osteogenic lineage.This work presents a facile technique to imprint nature-derived topographies on the surface of bioceramics which opens up opportunities for the development of bioresponsive interfaces in tissue engineering and regenerative medicine.

Calibrating SECCM measurements by means of a nanoelectrode ruler.The intrinsic oxygen reduction activity of PtNi catalyst nanoparticles

Scanning electrochemical cell microscopy(SECCM)is increasingly applied to determine the intrinsic catalytic activity of single electrocatalyst particle.This is especially feasible if the catalyst nanoparticles are large enough that they can be found and counted in post-SECCM scanning electron microscopy images.Evidently,this becomes impossible for very small nanoparticles and hence,a catalytic current measured in one landing zone of the SECCM droplet cannot be correlated to the exact number of catalyst particles.We show,that by introducing a ruler method employing a carbon nanoelectrode decorated with a countable number of the same catalyst particles from which the catalytic activity can be determined,the activity determined using SECCM from many spots can be converted in the intrinsic catalytic activity of a certain number of catalyst nanoparticles.

Frontier luminous strategy of functional silica nanohybrids in sensing and bioimaging:From ACQ to AIE

Fluorescent silica organic-inorganic nanohybrids which combine designable luminescence performance of organic fluorescent dyes and various outstanding advantages of silica nanomaterials have attracted increasing research interests in these fascinating areas.Optical transparency and facile functional modification properties of silica material provide great opportunities to integrate desired fluorescent molecules for various frontier luminous applications.However,conventional organic dyes are typically subject to aggregation-caused quenching due to their aggregation in silica matrix,which could be detrimental for their performance in sensing and biomedical applications.The appearance of aggregation-induced emission luminogens(AIEgens)paves a new way for developing highly efficient fluorescent silica nanohybrids(FSNs).FSNs with intensive luminescence could be obtained due to the formation of aggregates and the restricted intramolecular motion of AIEgens in silica inorganic matrix.In this review,the reported fabrication methodologies of various FSNs based on colloidal silica nanoparticles(SNs)and mesoporous SNs including physical entrapment and covalent strategies are summarized.Especially,the AIEgens-functionalized silica hybrid nanomaterials are introduced in detail.Furthermore,chemical sensing,biosensing,and bioimaging applications of resultant FSNs are also discussed.