Functional microfluidics:theory,microfabrication,and applications

Microfluidic devices are composed of microchannels with a diameter ranging from ten to a few hundred micrometers.Thus,quite a small(10-9–10-18l)amount of liquid can be manipulated by such a precise system.In the past three decades,significant progress in materials science,microfabrication,and various applications has boosted the development of promising functional microfluidic devices.In this review,the recent progress on novel microfluidic devices with various functions and applications is presented.First,the theory and numerical methods for studying the performance of microfluidic devices are briefly introduced.Then,materials and fabrication methods of functional microfluidic devices are summarized.Next,the recent significant advances in applications of microfluidic devices are highlighted,including heat sinks,clean water production,chemical reactions,sensors,biomedicine,capillaric circuits,wearable electronic devices,and microrobotics.Finally,perspectives on the challenges and future developments of functional microfluidic devices are presented.This review aims to inspire researchers from various fields engineering,materials,chemistry,mathematics,physics,and more—to collaborate and drive forward the development and applications of functional microfluidic devices,specifically for achieving carbon neutrality.

Femtosecond laser-induced nanoparticle implantation into flexible substrate for sensitive and reusable microfluidics SERS detection

Surface-enhanced Raman spectroscopy(SERS)microfluidic system,which enables rapid detection of chemical and biological analytes,offers an effective platform to monitor various food contaminants and disease diagnoses.The efficacy of SERS microfluidic systems is greatly dependent on the sensitivity and reusability of SERS detection substrates to ensure repeated use for prolonged periods.This study proposed a novel process of femtosecond laser nanoparticle array(NPA)implantation to achieve homogeneous forward transfer of gold NPA on a flexible polymer film and accurately integrated it within microfluidic chips for SERS detection.The implanted Au-NPA strips show a remarkable electromagnetic field enhancement with the factor of 9×108 during SERS detection of malachite green(MG)solution,achieving a detection limit lower than 10 ppt,far better than most laser-prepared SERS substrates.Furthermore,Au-NPA strips show excellent reusability after several physical and chemical cleaning,because of the robust embedment of laser-implanted NPA in flexible substrates.To demonstrate the performance of Au-NPA,a SERS microfluidic system is built to monitor the online oxidation reaction between MG/NaClO reactants,which helps infer the reaction path.The proposed method of nanoparticle implantation is more effective than the direct laser structuring technique.It provides better performance for SERS detection,robustness of detection,and substrate flexibility and has a wider range of applications for microfluidic systems without any negative impact.

Micro-nano-fabrication of green functional materials by multiphase microfluidics for environmental and energy applications

Multiphase microfluidic has emerged as a powerful platform to produce novel materials with tailor-designed functionalities,as microfluidic fabrication provides precise controls over the size,component,and structure of resultant materials.Recently,functional materials with well-defined micro-/nanostructures fabricated by microfluidics find important applications as environmental and energy materials.This review first illustrated in detail how different structures or shapes of droplet and jet templates are formed by typical configurations of microfluidic channel networks and multiphase flow systems.Subsequently,recent progresses on several representative energy and environmental applications,such as water purification,water collecting and energy storage,were overviewed.Finally,it is envisioned that integrating microfluidics and other novel materials will play increasing important role in contributing environmental remediation and energy storage in near future.

Orthopedic revolution:The emerging role of nanotechnology

This review summarizes the latest progress in orthopedic nanotechnology,ex-plores innovative applications of nanofibers in tendon repair,and evaluates the potential of selenium and cerium oxide nanoparticles in osteoarthritis and osteo-blast differentiation.This review also describes the emerging applications of inje-ctable hydrogels in cartilage engineering,emphasizing the critical role of inter-disciplinary research and highlighting the challenges and future prospects of in-tegrating nanotechnology into orthopedic clinical practice.This comprehensive approach provides a holistic perspective on the transformative impact of nanote-chnology in orthopedics,offering valuable insights for future research and clinical applications.

Nanotechnology in Nuclear Reactors: Innovations in Fusion and Fission Power Generation

This article explores the transformative potential of nanotechnology and MMs(memory metals)in enhancing the design and operation of nuclear reactors,encompassing both fission and fusion technologies.Nanotechnology,with its ability to engineer materials at the atomic scale,offers significant improvements in reactor safety,efficiency,and longevity.In fission reactors,nanomaterials enhance fuel rod integrity,optimize thermal management,and improve in-core instrumentation.Fusion reactors benefit from nanostructured materials that bolster containment and heat dissipation,addressing critical challenges in sustaining fusion reactions.The integration of SMAs(shape memory alloys),or MMs,further amplifies these advancements.These materials,characterized by their ability to revert to a pre-defined shape under thermal conditions,provide self-healing capabilities,adaptive structural components,and enhanced magnetic confinement.The synergy between nanotechnology and MMs represents a paradigm shift in nuclear reactor technology,promising a future of cleaner,more efficient,and safer nuclear energy production.This innovative approach positions the nuclear industry to meet the growing global energy demand while addressing environmental and safety concerns.

From Droplets and Particles to Hierarchical Spatial Organization： Nanotechnology Challenges for Microfluidics

The compartimentation of fluids in the microliter, nanoliter and picoliter range leads recently to many applications of microfluidics in material development, diagnostics and biological screenings. Droplet-based microfluidics allows the improvement of nanoparticle homogeneity and the tuning of particle properties. It supports combinatorial synthesis of inorganic as well as organic substances and can be applied for the cultivation and screening of bacteria, eucaryotic cells and fish embryos. The well-ordered handling and the addressing of microfluid segments improves the information transfer between chemical, biological and electronic systems. Despite this remarkable technical progress, there is a particular importance of microfluidics for future nanotechnological solutions. The hierarchical spatial organization of liquids, particles and gels in microfluidics represents a fundamental biomimetic principle which overcomes the limits of planar technology and opens the gate for realizing complex structured threedimensional nanoarchitectures. Recent applications of microstructured fluids in chemistry and biology and concepts for future developments will be discussed.

Green microfluidics in microchemical engineering for carbon neutrality

The concept of“carbon neutrality”poses a huge challenge for chemical engineering and brings great opportunities for boosting the development of novel technologies to realize carbon offsetting and reduce carbon emissions.Developing high-efficient,low-cost,energy-efficient and eco-friendly microfluidicbased microchemical engineering is of great significance.Such kind of“green microfluidics”can reduce carbon emissions from the source of raw materials and facilitate controllable and intensified microchemical engineering processes,which represents the new power for the transformation and upgrading of chemical engineering industry.Here,a brief review of green microfluidics for achieving carbon neutral microchemical engineering is presented,with specific discussions about the characteristics and feasibility of applying green microfluidics in realizing carbon neutrality.Development of green microfluidic systems are categorized and reviewed,including the construction of microfluidic devices by bio-based substrate materials and by low carbon fabrication methods,and the use of more biocompatible and nondestructive fluidic systems such as aqueous two-phase systems(ATPSs).Moreover,low carbon applications benefit from green microfluidics are summarized,ranging from separation and purification of biomolecules,high-throughput screening of chemicals and drugs,rapid and cost-effective detections,to synthesis of fine chemicals and novel materials.Finally,challenges and perspectives for further advancing green microfluidics in microchemical engineering for carbon neutrality are proposed and discussed.

Applications of nanotechnology in medical field: a brief review

Nanotechnology has extensive application as nanomedicine in the medical field.Some nanoparticles have possible applications in novel diagnostic instruments,imagery and methodologies,targeted medicinal products,pharmaceutical products,biomedical implants,and tissue engineering.Today treatments of high toxicity can be administered with improved safety using nanotechnology,such as chemotherapeutic cancer drugs.Further,wearable gadgets can detect crucial changes in vital signs,cancer cell conditions,and infections that are genuinely happening in the body.We anticipate these technologies to provide doctors with considerably much better direct access to critical data on the reasons for changes in the signs of life or illness because of the technological presence at the source of the problem.Biomedicine can be utilised for therapies with predictive analytics and artificial intelligence.For carrying out this study,relevant papers on Nanotechnology in the medical field from Scopus,Google scholar,ResearchGate,and other research platforms are identified and studied.The study discusses different types of Nanoparticles used in the medical field.This paper discusses nanotechnology applications in the medical field.The class,features,and characteristics of Nanotechnology for medicine are also briefed.Scientists,governments,civil society organisations,and the general public will need to collaborate across sectors to assess the significance of nanotechnology and guide its advancement in various fields.The current research includes several possible Nanotechnology uses in the medical field.As a result,the study provides a brief and well-organised report on nanotechnology that should be valuable to researchers,engineers,and scientists for future research projects.

Thermal and ignition properties of hexanitrostilbene(HNS) microspheres prepared by droplet microfluidics

HNS-IV(Hexanitrostilbene-IV) is the main charge of the exploding foil initiators(EFI), and the microstructure of the HNS will directly affect its density, flowability, sensitivity, and stability. HNS microspheres were prepared using droplet microfluidics, and the particle size, morphology, specific surface area, thermal performance, and ignition threshold of the HNS microspheres were characterized and tested. The results shown that the prepared HNS microspheres have high sphericity, with an average particle size of 20.52 μm(coefficient of variation less than 0.2), and a specific surface area of 21.62 m^(2)/g(6.87 m^(2)/g higher than the raw material). Without changing the crystal structure and thermal stability of HNS-IV, this method significantly enhances the sensitivity of HNS-IV to short pulses and reduces the ignition threshold of the slapper detonator to below 1000 V. This will contribute to the miniaturization and low cost of EFI.

Application of nanotechnology in reversing therapeutic resistance and controlling metastasis of colorectal cancer

Colorectal cancer(CRC)is the most common digestive malignancy across the world.Its first-line treatments applied in the routine clinical setting include surgery,chemotherapy,radiotherapy,targeted therapy,and immunotherapy.However,resistance to therapy has been identified as the major clinical challenge that fails the treatment method,leading to recurrence and distant metastasis.An increasing number of studies have been attempting to explore the underlying mechanisms of the resistance of CRC cells to different therapies,which can be summarized into two aspects:(1)The intrinsic characters and adapted alterations of CRC cells before and during treatment that regulate the drug metabolism,drug transport,drug target,and the activation of signaling pathways;and(2)the suppressive features of the tumor microenvironment(TME).To combat the issue of therapeutic resistance,effective strategies are warranted with a focus on the restoration of CRC cells’sensitivity to specific treatments as well as reprogramming impressive TME into stimulatory conditions.To date,nanotechnology seems promising with scope for improvement of drug mobility,treatment efficacy,and reduction of systemic toxicity.The instinctive advantages offered by nanomaterials enable the diversity of loading cargoes to increase drug concentration and targeting specificity,as well as offer a platform for trying the combination of different treatments to eventually prevent tumor recurrence,metastasis,and reversion of therapy resistance.The present review intends to summarize the known mechanisms of CRC resistance to chemotherapy,radiotherapy,immunotherapy,and targeted therapy,as well as the process of metastasis.We have also emphasized the recent application of nanomaterials in combating therapeutic resistance and preventing metastasis either by combining with other treatment approaches or alone.In summary,nanomedicine is an emerging technology with potential for CRC treatment;hence,efforts should be devoted to targeting cancer cells for the restoration of therapeutic sensitivity as well as reprogramming the TME.It is believed that the combined strategy will be beneficial to achieve synergistic outcomes contributing to control and management of CRC in the future.

Advances of nanotechnology applied to cancer stem cells

Cancer stem cells(CSCs)are a small proportion of the cells that exist in cancer tissues.They are considered to be the culprit of tumor genesis,development,drug resistance,metastasis and recurrence because of their self-renewal,proliferation,and differentiation potential.The elimination of CSCs is thus the key to cure cancer,and targeting CSCs provides a new method for tumor treatment.Due to the advantages of controlled sustained release,targeting and high biocompatibility,a variety of nanomaterials are used in the diagnosis and treatments targeting CSCs and promote the recognition and removal of tumor cells and CSCs.This article mainly reviews the research progress of nanotechnology in sorting CSCs and nanodrug delivery systems targeting CSCs.Furthermore,we identify the problems and future research directions of nanotechnology in CSC therapy.We hope that this review will provide guidance for the design of nanotechnology as a drug carrier so that it can be used in clinic for cancer therapy as soon as possible.

Microfluidic-oriented synthesis of enriched iridium nanodots/carbon architecture for robust electrocatalytic nitrogen fixation

Electrocatalytic nitrogen reduction reaction(NRR)is considered as a promising candidate to achieve ammonia synthesis because of clean electric energy,moderate reaction condition,safe operating process and harmless by-products.However,the chemical inertness of nitrogen and poor activated capacity on catalyst surface usually produce low ammonia yield and faradic efficiency.Herein,the microfluidic technology is proposed to efficiently fabricate enriched iridium nanodots/carbon architecture.Owing to in-situ co-precipitation reaction and microfluidic manipulation,the iridium nanodots/carbon nanomaterials possess small average size,uniform dispersion,high conductivity and abundant active sites,producing good proton activation and rapid electrons transmission and moderate adsorption/desorption capacity.As a result,the as-prepared iridium nanodots/carbon nanomaterials realize large ammonia yield of 28.73 μg h^(-1) cm^(-2) and faradic efficiency of 9.14%in KOH solution.Moreover,the high ammonia yield of 11.21 μg h^(-1) cm^(-2) and faradic efficiency of 24.30%are also achieved in H_(2)SO_(4) solution.The microfluidic method provides a reference for large-scale fabrication of nano-sized catalyst materials,which may accelerate the progress of electrocatalytic NRR in industrialization field.

Nanotechnology:A New Strategy for Lung Cancer Treatment Targeting Pro-Tumor Neutrophils

Primary and metastatic lung cancers are malignant lung tumors each with of which has a different pathogenesis,although both threaten patient lives.Tumor development and progression involve communication between tumor cells and the host microenvironment.Neutrophils are the most abundant immune cells in the tumor microenvironment(TME);they participate in the generation of an inflammatory milieu and influence patient survival through their anti-and pro-tumor abilities.Neutrophils can be classified into various categories according to different criteria;frequent categories include N1 antitumor neutrophils and N2 immunosuppressive neutrophils.The antitumor effects of neutrophils are reported to be mediated through a combination of reactive oxygen species,tumor necrosis factor-related apoptosis-inducing ligand,and receptor for advanced glycation end-products–cathepsin G association,as well as the regulation of the activities of other immune cells.There have also been reports that neutrophils can function as tumor promoters that contribute to lung cancer progression and metastasis by influencing processes including carcinogenesis,angiogenesis,cancer cell proliferation,and invasion ability,as well as having similar roles in the lung metastasis of other cancers.The rapid development of nanotechnology has provided new strategies for cancer treatment targeting neutrophils.

Recent progress in aptamer-based microfluidics for the detection of circulating tumor cells and extracellular vesicles

Liquid biopsy is a technology that exhibits potential to detect cancer early,monitor therapies,and predict cancer prognosis due to its unique characteristics,including noninvasive sampling and real-time analysis.Circulating tumor cells(CTCs)and extracellular vesicles(EVs)are two important components of circulating targets,carrying substantial disease-related molecular information and playing a key role in liquid biopsy.Aptamers are single-stranded oligonucleotides with superior affinity and specificity,and they can bind to targets by folding into unique tertiary structures.Aptamer-based microfluidic platforms offer new ways to enhance the purity and capture efficiency of CTCs and EVs by combining the advantages of microfluidic chips as isolation platforms and aptamers as recognition tools.In this review,we first briefly introduce some new strategies for aptamer discovery based on traditional and aptamer-based microfluidic approaches.Then,we subsequently summarize the progress of aptamer-based microfluidics for CTC and EV detection.Finally,we offer an outlook on the future directional challenges of aptamer-based microfluidics for circulating targets in clinical applications.

Junction matters in hydraulic circuit bio-design of microfluidics

Microfluidic channels are at micrometer scales;thus,their fluid flows are laminar,resulting in the linear dependence of pressure drop on flow rate in the length of the channel.The ratio of the pressure drop to flow rate,referred to as resistance,depends on channel size and dynamic viscosity.Usually,a microfluidic chip is analogous to an electric circuit in design,but the design is adjusted to optimize channel size.However,whereas voltage loss is negligible at the nodes of an electric circuit,hydraulic pressure drops at the nodes of microfluidic chips by a magnitude are comparable to the pressure drops in the straight channels.Here,we prove by experiment that one must fully consider the pressure drops at nodes so as to accurately design a precise microfluidic chip.In the process,we numerically calculated the pressure drops at hydraulic nodes and list their resistances in the range of flows as concerned.We resorted to machine learning to fit the calculated results for complex junctions.Finally,we obtained a library of node resistances for common junctions and used them to design three established chips that work for single-cell analysis and for precision allocation of solutes(in gradient and averaging concentration microfluidic networks).Endothelial cells were stimulated by generating concentrations of adriamycin hydrochloride from the last two microfluidic networks,and we analyzed the response of endothelial cells.The results indicate that consideration of junction resistances in design calculation brings experimental results closer to the design values than usual.This approach may therefore contribute to providing a platform for the precise design of organ chips.

Minimizing sperm oxidative stress using nanotechnology for breeding programs in rams

Background Artificial insemination(AI)is a routine breeding technology in animal reproduction.Nevertheless,the temperature-sensitive nature and short fertile lifespan of ram sperm samples hamper its use in AI.In this sense,nanotechnology is an interesting tool to improve sperm protection due to the development of nanomaterials for AI,which could be used as delivery vehicles.In this work,we explored the feasibility of vitamin E nanoemulsion(NE)for improving sperm quality during transport.Results With the aim of evaluating this proposal,ejaculates of 7 mature rams of Manchega breed were collected by artificial vagina and extended to 60×10^(6)spz/mL in AndromedR.Samples containing control and NE(12 mmol/L)with and without exogenous oxidative stress(100μmol/L Fe2+/ascorbate)were stored at 22 and 15℃and motility(CASA),viability(YO-PRO/PI),acrosomal integrity(PNA-FITC/PI),mitochondrial membrane potential(Mitotracker Deep Red 633),lipoperoxidation(C11 BODIPY 581/591),intracellular reactive oxygen species(ROS)production and DNA status(SCSAR)monitored during 96 h.Our results show that NE could be used to maintain ram spermatozoa during transport at 15 and 22℃for up to 96 h,with no appreciable loss of kinematic and physiological characteristics of freshly collected samples.Conclusions The storage of ram spermatozoa in liquid form for 2-5 d with vitamin E nanoemulsions may lead more flexibility to breeders in AI programs.In view of the potential and high versatility of these nanodevices,further studies are being carried out to assess the proposed sperm preservation medium on fertility after artificial insemination.

An integrated microfluidics platform with high-throughput single-cell cloning array and concentration gradient generator for efficient cancer drug effect screening

Background:Tumor cell heterogeneity mediated drug resistance has been recognized as the stumbling block of cancer treatment.Elucidating the cytotoxicity of anticancer drugs at single-cell level in a high-throughput way is thus of great value for developing precision therapy.However,current techniques suffer from limitations in dynamically characterizing the responses of thousands of single cells or cell clones presented to multiple drug conditions.Methods:We developed a new microfluidics-based“SMART”platform that is Simple to operate,able to generate a Massive single-cell array and Multiplex drug concentrations,capable of keeping cells Alive,Retainable and Trackable in the microchambers.These features are achieved by integrating a Microfluidic chamber Array(4320 units)and a sixConcentration gradient generator(MAC),which enables highly efficient analysis of leukemia drug effects on single cells and cell clones in a high-throughput way.Results:A simple procedure produces 6 on-chip drug gradients to treat more than 3000 single cells or single-cell derived clones and thus allows an efficient and precise analysis of cell heterogeneity.The statistic results reveal that Imatinib(Ima)and Resveratrol(Res)combination treatment on single cells or clones is much more efficient than Ima or Res single drug treatment,indicated by the markedly reduced half maximal inhibitory concentration(IC50).Additionally,single-cell derived clones demonstrate a higher IC_(50) in each drug treatment compared to single cells.Moreover,primary cells isolated from two leukemia patients are also found with apparent heterogeneity upon drug treatment on MAC.Conclusions:This microfluidics-based“SMART”platform allows high-throughput single-cell capture and culture,dynamic drug-gradient treatment and cell response monitoring,which represents a new approach to efficiently investigate anticancer drug effects and should benefit drug discovery for leukemia and other cancers.

Molecular Dynamics (MD) Applications in Materials Science and Engineering and Nanotechnology

Molecular dynamics (MD) is a computer simulation technique that helps to explore the behavior and properties of molecules and atoms. MD has been used in research and development in many spaces, including materials science and engineering and nanotechnology. MD has been proven useful in topics like the nano-engineering of construction materials, correcting graphene planar defects, studying self-assembling bio-materials, and the densification, consolidation, and sintering of nanocrystalline materials.

Simulation and fabrication of in vitro microfluidic microelectrode array chip for patterned culture and electrophysiological detection of neurons

To enable the detection and modulation of modularized neural networks in vitro,this study proposes a microfluidic microelectrode array chip for the cultivation,compartmentalization,and control of neural cells.The chip was designed based on the specific structure of neurons and the requirements for detection and modulation.Finite-element analysis of the chip’s flow field was conducted using the COMSOL Multiphysics software,and the simulation results show that the liquid within the chip can flow smoothly,ensuring stable flow fields that facilitate the uniform growth of neurons within the microfluidic channels.By employing MEMS technology in combination with nanomaterial modification techniques,the microfluidic microelectrode array chip was fabricated successfully.Primary hippocampal neurons were cultured on the chip,forming a well-defined neural network.Spontaneous electrical activity of the detected neurons was recorded,exhibiting a 23.7%increase in amplitude compared to neuronal discharges detected on an open-field microelectrode array.This study provides a platform for the precise detection and modulation of patterned neuronal growth in vitro,potentially serving as a novel tool in neuroscience research.

High-throughput microfluidic production of carbon capture microcapsules:fundamentals,applications,and perspectives

In the last three decades,carbon dioxide(CO_(2)) emissions have shown a significant increase from various sources.To address this pressing issue,the importance of reducing CO_(2) emissions has grown,leading to increased attention toward carbon capture,utilization,and storage strategies.Among these strategies,monodisperse microcapsules,produced by using droplet microfluidics,have emerged as promising tools for carbon capture,offering a potential solution to mitigate CO_(2) emissions.However,the limited yield of microcapsules due to the inherent low flow rate in droplet microfluidics remains a challenge.In this comprehensive review,the high-throughput production of carbon capture microcapsules using droplet microfluidics is focused on.Specifically,the detailed insights into microfluidic chip fabrication technologies,the microfluidic generation of emulsion droplets,along with the associated hydrodynamic considerations,and the generation of carbon capture microcapsules through droplet microfluidics are provided.This review highlights the substantial potential of droplet microfluidics as a promising technique for large-scale carbon capture microcapsule production,which could play a significant role in achieving carbon neutralization and emission reduction goals.