nanoparticle

摘要： Injuries to the central nervous system(CNS)such as stroke,brain,and spinal cord trauma often result in permanent disabilities because adult CNS neurons only exhibit limited axon regeneration.The brain has a surprising intrinsic capability of recovering itself after injury.However,the hostile extrinsic microenvironment significantly hinders axon regeneration.Recent advances have indicated that the inactivation of intrinsic regenerative pathways plays a pivotal role in the failure of most adult CNS neuronal regeneration.Particularly,substantial evidence has convincingly demonstrated that the mechanistic target of rapamycin(mTOR)signaling is one of the most crucial intrinsic regenerative pathways that drive axonal regeneration and sprouting in various CNS injuries.In this review,we will discuss the recent findings and highlight the critical roles of mTOR pathway in axon regeneration in different types of CNS injury.Importantly,we will demonstrate that the reactivation of this regenerative pathway can be achieved by blocking the key mTOR signaling components such as phosphatase and tensin homolog(PTEN).Given that multiple mTOR signaling components are endogenous inhibitory factors of this pathway,we will discuss the promising potential of RNA-based therapeutics which are particularly suitable for this purpose,and the fact that they have attracted substantial attention recently after the success of coronavirus disease 2019 vaccination.To specifically tackle the blood-brain barrier issue,we will review the current technology to deliver these RNA therapeutics into the brain with a focus on nanoparticle technology.We will propose the clinical application of these RNA-mediated therapies in combination with the brain-targeted drug delivery approach against mTOR signaling components as an effective and feasible therapeutic strategy aiming to enhance axonal regeneration for functional recovery after CNS injury.

摘要： Wellbore stability is essential for safe and efficient drilling during oil and gas exploration and development.This paper introduces a hydrophobic nano-silica(HNS)for use in strengthening the wellbore wall when using a water-based drilling fluid(WBF).The wellbore-strengthening performance was studied using the linear swelling test,hot-rolling recovery test,and compressive strength test.The mechanism of strengthening the wellbore wall was studied by means of experiments on the zeta potential,particle size,contact angle,and surface tension,and with the use of a scanning electron microscope(SEM).The surface free energy changes of the shale before and after HNS treatment were also calculated using the contact angle method.The experimental results showed that HNS exhibited a good performance in inhibiting shale swelling and dispersion.Compared with the use of water,the use of HNS resulted in a 20%smaller linear swelling height of the bentonite pellets and an 11.53 times higher recovery of water-sensitive shale—a performance that exceeds those of the commonly used shale inhibitors KCl and polyamines.More importantly,the addition of HNS was effective in preventing a decrease in shale strength.According to the mechanism study,the good wellbore-strengthening performance of HNS can be attributed to three aspects.First,the positively charged HNS balances parts of the negative charges of clay by means of electrostatic adsorption,thus inhibiting osmotic hydration.Second,HNS fabricates a lotus-leaf-like surface with a micro-nano hierarchical structure on shale after adsorption,which significantly increases the water contact angle of the shale surface and considerably reduces the surface free energy,thereby inhibiting surface hydration.Third,the decrease in capillary action and the effective plugging of the shale pores reduce the invasion of water and promote wellbore stability.The approach described herein may provide an avenue for inhibiting both the surface hydration and the osmotic hydration of shale.

摘要： Nanofluid offers more opportunities and challenges over the traditional surfactant and polymer solutions during enhanced oil recovery(commonly referred to as tertiary oil recovery)due to its remarkable properties.This review mainly discusses the preparation methods of amphiphilic nanoparticles due to their higher interface activity than sole hydrophilic or hydrophobic nanoparticles(SHNPs).The nanofluids’stability is reviewed in this work.Moreover,the mechanisms of nanofluids in enhancing oil recovery(N-EOR)in terms of interfacial tension reduction,wettability alteration,foam stabilization,emulsion stabilization,structural disjoining pressure,and depressurization-increasing injection are mainly summarized and reviewed.Also,the synergistic effects of nanofluids and traditional surfactants and polymers are discussed.Finally,nanofluids’challenges and prospects are also outlined.The nanofluids can still be regarded as an outstanding candidate for enhancing oil recovery significantly in the future although there are limitations on their applications from laboratory scale to field scale.

摘要： Psoriasis is a common chronic immune-mediated skin disease characterized by hyperproliferation and aberrant differentiation of keratinocytes and massive infiltration of inflammatory immune cells.Recent studies showed that Signal Transducer and Activator of Transcription 3(STAT3),which plays an important role in cell survival,proliferation,differentiation,angiogenesis,and immune responses,is constitutively activated in epidermal keratinocytes of human psoriatic skin lesions.In addition,STAT3 promotes the differentiation and expansion of T cells and facilitates cytokine production,thereby exacerbating the condition of psoriasis.Alantolactone(ALT)is a sesquiterpene lactone compound that could selectively suppress STAT3 activation,but its effectiveness and application in psoriasis treatment have not been determined.In this study,we developed ALT loaded chitosan/hyaluronic acid nanoparticles(CHALT),and investigated its therapeutic potential for psoriasis therapy.CHALT effectively abrogated the hyperproliferation by inducing ROS-mediated apoptosis with loss of mitochondrialmembrane potential,and also inhibited IL-6-induced STAT3 signaling activation and inflammatory reaction in HaCaT cell line.In an Imiquimod(IMQ)-induced psoriasis model,the topical treatment of psoriasis lesions with CHALT effectively attenuated the STAT3 hyperactivation within keratinocytes and ameliorated the symptoms of psoriasis.In addition,it was found that CHALT restricted the recruitment of immune cells.These results indicated that ALT-based nanoformulation CHALT holds great potential for psoriasis therapy.

摘要： Single particle tracking(SPT)has long been utilized for investigation of complex system dynamics such as nanoparticle-cell interaction,however,the analysis of individual particle motions is always a difficult issue.Existing methods treat each data point or fragment on the recorded trajectory as an isolated"atom"and determine their relationship based on externally predefined models or physical states,which inevitably lead to oversimplification of the associated spatiotemporal complexity.Herein,inspired by the historical analysis in social science,we propose a modeless preprocessing framework for SPT analysis based on the"history"of the particle.This new strategy consists of 3 steps:(1)assign a"history"to each data point and construct successive overlapped historical vectors;(2)perform unsupervised clustering in the vector space to find their relative differences;(3)project differences back to the trajectory by coloring each point accordingly for visualization.As a result,the inner heterogeneity of the particle motion self-emerges as a colored trajectory,exhibiting a global picture of the local state transitions and providing valuable information for further model-based analysis.Since the complexity issues at various spatiotemporal scales have attracted increasing attention,and individual objects such as single molecules,cells,vehicles and even stars in the universe could all be treated as"single particles",this presuppositionless data preprocessing approach could help the investigations of many complex systems in fundamental research.

摘要： Microbiologically influenced corrosion is a global problem especially materials used in marine engineering.In that respect,inhibitors are widely used to control fouling and corrosion in marine systems.Most techniques used in inhibitor production are expensive and considered hazardous to the ecosystem.Therefore,scientists are motivated to explore natsural and green products as potent corrosion inhibitors especially in nano size.In this study,antibacterial and anticorrosive properties of green silver nanoparticles(AgNPs)were studied through weight loss,electrochemical characterization,and surface analysis techniques.The corrosion of copper(Cu)in artificial seawater(ASW),Halomonas variabilis(H.variabilis)NOSK,and H.variabilis+AgNPs was monitored using electrochemical measurements like open circuit potential(OCP),electrochemical impedance spectroscopy(EIS),and potentiodynamic polarization curves.AgNPs showed excellent antibacterial activity against pathogenic microorganisms.Electrochemical studies demonstrate a noticeable decrease in OCP and current density in ASW containing H.variabilis+AgNPs compared to both ASW and ASW inoculated with bacterium,which confirmed the decrease of corrosion rate of copper.Furthermore,the obtained voltammograms show that the silver nanoparticles were adsorbed on the copper electrode surface from the corrosion solution.Thus,the results prove that the novel idea of green silver nanoparticles acts as an anticorrosive film in the marine environment.

摘要： Photoresists are radiation-sensitive materials used for forming patterns to build up IC devices.To date,most photoresists have been based on organic polymers,which have been dominating the semiconductor industries over the past few decades.It is obvious that extreme ultraviolet(EUV)lithography has become the next-generation lithography technology.The development of comprehensive performance EUV resist is one of the most critical issues.However,organic polymeric photoresists are difficult to meet the harsh requirements of EUV lithography.Pure inorganic photoresists such as metal salts,hydrogen silsesquioxane(HSQ)are expected for EUV lithography due to their high resistance and high resolution.But the low sensitivity makes them not suitable for high volume manufacturing(HVM).Organic-inorganic hybrid photoresists,containing both organic and inorganic components,are regarded as one of the most promising EUV resists.They combine both merits of organic and inorganic materials and have significant advantages in machinability,etching resistance,EUV absorption,and chemical/thermal stability.Organic-inorganic hybrid photoresists are considered as ideal materials for realizing industrialgrade patterns below 10 nm.This review mainly focuses on the development of organic-inorganic hybrid photoresists over the past decade.

摘要： Adoptive cell therapy and Immune Checkpoint Blockade Inhibitors have recently revolutionized the field of oncology.However,these types of immunotherapeutic approaches have limited success in treating solid tumors.In particular,chimeric antigen receptor(CAR)-T cells efficacy is hampered by immunosuppressive signals in the tumor microenvironment(TME)and by a limited infiltration of re-infused T cells to the tumor site.The field of nanobiotechnology applied to oncology is also rapidly expanding.Nanoparticles-based delivery systems can be employed to modulate the activity of immune cells present in the TME enhancing the efficacy of CAR-T cells.Interestingly,nano-backpacks can be attached to CAR-T cells prior to re-infusion to support their homing to the tumor site and to slowly release immunopotentiators directly in the TME.Furthermore,nanovaccines can also be employed to support the in vivo expansion of CAR-T cells with consequent enhancement of their therapeutic potential.In this viewpoint,recent advancement in the field of nanobiotechnology to support CAR-T cell therapy will be discussed.The development of novel therapeutic CAR-T cells protocols together with nanotherapies is warranted in order to take full advantage of the high therapeutic potential of CAR-T cell therapy.

摘要： Carrier-free drug self-delivery systems consisting of amphiphilic drug-drug conjugate(ADDC)with well-defined structure and nanoscale features have drawn much attention in tumor drug delivery.Herein,we report a simple and effective strategy to prepare ADDC using derivatives of cisplatin(CP)and dasatinib(DAS),which further selfassembled to form reduction-responsive nanoparticles(CP-DDA NPs).DAS was modified with succinic anhydride and then connected with CP derivative by ester bonds.The size,micromorphology and in vitro drug release of CP-DDA NPs were characterized.The biocompatibility and bioactivity of these carrier-free nanoparticles were then investigated by HepG2 cells and H22-tumor bearing mice.In vitro and in vivo experiments proved that CPDDA NPs had excellent anti-tumor activity and significantly reduced toxicities.This study provides a new strategy to design the carrier-free nanomedicine composed of CP and DAS for synergistic tumor treatment.

摘要： Polyhedral shapes can be found in crystalline materials ranging from macroscopic natural mineral solids to microscopic or nanoscopic particles. These shapes originate from the crystallographic properties of the constituting material, and the outer shape depends on several unique habit planes. In this study, polyhedral crystal growth was simulated considering the surface energy and crystallographic characteristics. A series of polyhedrons, including cube, truncated hexahedron, cuboctahedron, truncated octahedron, and regular octahedron, was targeted. First, the polyhedron’s static surface energy and dynamic energy variation during crystal growth were computed. Then, the crystal-growth process was simulated based on the energy minimization policy. Interestingly, when the simulation began with truncated hexahedral nucleus, the shape changed to a cuboctahedron;however, a certain type of truncated octahedron was obtained when starting with different types of truncated octahedrons. In addition, once converged cuboctahedron abruptly changed the shape to a truncated octahedron as the crystal became larger. These results were supported by the static and dynamic energy curves. Furthermore, the method was applied to different materials by assuming virtual parameters, yielding various morphologies.