Micro & Nano Letters最新文献

{"title":"Barrier Performance of Spray Coated Cellulose Nanofibre Film","authors":"K. Shanmugam, N. Chandrasekar, R. Balaji","doi":"10.3390/micro3010014","DOIUrl":"https://doi.org/10.3390/micro3010014","url":null,"abstract":"Cellulose nanofibre (CNF) is the sustainable nanomaterial used for developing high-performance barrier materials that are renewable, recyclable, and biodegradable. The CNF film has very low oxygen permeability; however, its water vapor permeability is significantly higher than that of conventional packaging plastics. The fabrication method influences their barrier properties of the film. A spray-coating CNF on a stainless-steel plate was developed to form a compact film with two unique surfaces, namely a smooth layer on the base side and rough layer on the free side. It improves both the ease of preparation of the film and reduces the water vapour permeability via tailoring the basis weight and thickness of the film through simple adjusting CNF content in the suspension. The air permanence of the film from 1.0 wt.% to 2.0 wt.% CNF suspension is less than 0.003 µm/Pa·S confirming that is an impermeable film and proves a good packaging material. SEM, optical profilometry, and AFM revealed that the spray-coated surface was smooth and glossy. For sprayed CNF films with basis weight between 86.26 ± 13.61 and 155.85 ± 18.01 g/m2, WVP were ranged from 6.99 ± 1.17 × 10−11 to 4.19 ± 1.45 × 10−11 g/m·Pa·S. In comparison, the WVP of 100 g/m2 vacuum filtered CNF film was 5.50 ± 0.84 × 10−11 g/m·Pa·S, spray-coated film (of 96.6 g/m2) also show similar permeability at around 5.34 ± 0.603 × 10−11 g/m·Pa·S. The best performance was achieved with spraying of 2.0 wt.% CNF and a water vapour permeability of 3.91 × 10−11 g/m·s·Pa. Spray coated CNF film is impermeable against air and water vapour and a potential alternative to synthetic plastics.","PeriodicalId":18398,"journal":{"name":"Micro & Nano Letters","volume":"88 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88951369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphology and structure evolution of multilayered Ge/Si quantum dots grown by magnetron sputtering","authors":"Qijiang Shu,&nbsp;Pengru Huang,&nbsp;Xicheng Zhang,&nbsp;Linjing Yang,&nbsp;Donghai Ye,&nbsp;Li Yang,&nbsp;Hongxing Liu,&nbsp;Lei Chen","doi":"10.1049/mna2.12158","DOIUrl":"https://doi.org/10.1049/mna2.12158","url":null,"abstract":"<p>The authors prepared multilayered Si-based Ge quantum dots (Ge/Si QDs) by using the magnetron sputtering technique and reported the corresponding morphology evolution by atomic force microscope (AFM), scanning electron micrograph (SEM), X-ray photoelectron spectroscopy (XPS), Raman and X-ray diffraction (XRD) tests. The increased temperature can improve the Si-isolated-layer crystallinity and Ge atom mobility to increase the density, size, and spatial distribution uniformity of top-layer QDs. The morphology and vertical correlation between the layers of QDs at different temperatures exhibited different phenomena or laws, and had been explained in this paper. The authors’ work made it possible to control the quality of multilayer QDs by high-rate deposition technology and laid a foundation for the industrial production of multilayer QDs in the future.</p>","PeriodicalId":18398,"journal":{"name":"Micro & Nano Letters","volume":"18 2","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/mna2.12158","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50117170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polyaniline Hybrids with Biological Tissue, and Biological Polymers as Physiological—Electroactive Materials","authors":"M. Ichikawa, M. Otaki, H. Goto","doi":"10.3390/micro3010013","DOIUrl":"https://doi.org/10.3390/micro3010013","url":null,"abstract":"A sprout/polyaniline was synthesized via the chemical oxidative polymerization of aniline in the presence of natural sprout, based on a concept of cyborg plant composite. The composite consisted of both polyaniline and plants. The chemical structure was confirmed by infrared absorption spectroscopy measurements. Optical microscopy observation revealed that polyaniline was deposited into the micro-tissue of the sprout to form the conductive polymer bio-composite. Micro-optical fiber functions for the composite were visually confirmed. Furthermore, the sprout/polyaniline based organic diode exhibited an avalanche breakdown phenomenon. Next, a fucoidan/polyaniline composite as a physiological active material/conducting polymer composite was prepared. This composite showed good film-forming ability, electrochromism, and a micro-porous surface. This paper reports the preparation of conducting polymer composites with a combination of bio-tissue and bio-substance for the creation of bio-based electrically active organized architecture.","PeriodicalId":18398,"journal":{"name":"Micro & Nano Letters","volume":"39 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85821717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In-Vitro Cell Response to Strontium/Magnesium-Doped Calcium Phosphate Nanoparticles","authors":"K. Kostka, S. Hosseini, M. Epple","doi":"10.3390/micro3010012","DOIUrl":"https://doi.org/10.3390/micro3010012","url":null,"abstract":"Calcium phosphate nanoparticles are highly biocompatible and biodegradable in bone regeneration. On the other hand, strontium and magnesium enhance the formation of bone. The substitution of calcium by strontium and magnesium is an efficient way to improve the biological properties of calcium phosphate-based biomaterials. Strontium-doped calcium phosphate nanoparticles and magnesium-doped calcium phosphate nanoparticles with degrees of cation substitution of 5, 10, 15, and 20 mol% with respect to calcium were prepared by precipitation, followed by surface functionalization with polyethyleneimine (PEI, cationic) or carboxymethylcellulose (CMC, anionic). The nanoparticles were characterized by dynamic light scattering (DLS), zeta potential measurement, scanning electron microscopy (SEM), atomic absorption spectrometry (AAS), energy dispersive X-ray analysis (EDX), and X-ray powder diffraction (XRD). The particles were approximately spherical (diameter 40–70 nm). The addition of magnesium and strontium considerably decreased the internal crystallinity, i.e., the doped particles were almost X-ray amorphous. The cell-biological effects were assessed on three different cell lines, i.e., HeLa cells, MG63 cells, and MC3T3 cells. Cell viability tests (MTT) showed a low cytotoxicity, the alkaline phosphatase (ALP) activity was strongly increased, and the nanoparticles were taken up well by the three cell lines.","PeriodicalId":18398,"journal":{"name":"Micro & Nano Letters","volume":"109 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86007060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Graphene Formation through Spontaneous Exfoliation of Graphite by Chlorosulfonic Acid: A DFT Study","authors":"Alfredo Bol-Arreba, Isabel G. Ayala, N. A. Cordero","doi":"10.3390/micro3010011","DOIUrl":"https://doi.org/10.3390/micro3010011","url":null,"abstract":"Using exfoliating agents is one of the most promising ways for large-scale production of liquid dispersed graphenic materials from graphite. Therefore, it is crucial to know the reason why some molecules have a larger exfoliating power than others. The highest reported experimental yield for the liquid phase single-surfactant spontaneous exfoliation of graphite, i.e., without sonication, has been obtained using chlorosulfonic acid. The ability of this acid to disperse graphite is studied within the framework of Density Functional Theory (DFT). Equilibrium configurations, electron transfers, binding energies, and densities of states are presented for two acid concentrations and for two situations: adsorption (on monolayer and bilayer graphene) and intercalation (in between simple hexagonal and Bernal-stacked bilayer graphene). Experimental exfoliation power and dispersion stability are explained in terms of charge transfer—the largest found among several studied exfoliating and surfactant agents—facilitated by the good geometrical matching of chlorosulfonic acid molecules to constituent carbon rings of graphene. This matching is in the origin of the tendency toward adsorption of chlorosulfonic acid molecules on graphene monolayers when they separate, originating the charging of the monolayers that precludes their reaggregation.","PeriodicalId":18398,"journal":{"name":"Micro & Nano Letters","volume":"42 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75362724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chitosan/Hydroxyapatite Scaffolds with P28 as a Promising Osteoinductive Scaffold for Bone Healing Applications","authors":"Farah Alwani Azaman, F. Daubiné, Amélie Lebatard, Margaret Brennan Fournet, D. Devine","doi":"10.3390/micro3010010","DOIUrl":"https://doi.org/10.3390/micro3010010","url":null,"abstract":"Despite bone’s inherent ability to heal, large bone defects remain a major clinical concern. This study proposes an off-the-shelf treatment combining chitosan/hydroxyapatite (CS/HAp) scaffolds, covalently linked with either bone morphogenetic protein-2 (BMP-2) or its related peptide P28 via a UV crosslinking process. Although covalently binding the growth factors was reported as a great alternative to the conventionally physical adsorption and encapsulation methods, this method presents the risk of altering the molecular activity and interaction of the growth factors. Therefore, alkaline phosphatase (ALP) activity and alizarin red staining (ARS) with a quantitative cetylpyridinium chloride (CPC) assay were conducted to validate that our photo-crosslinking fabrication method did not interfere with the functionality of the growth factors. The ALP activity of C2C12 with 100 µg/mL P28 was found to be comparable to 0.5 µg/mL BMP-2 after two weeks, where 0.001 U/mL was recorded for both treatments. The C2C12 cultured with CS/HAp/BMP-2 and CS/HAp/P28 scaffolds also showed an increased ALP activity compared to the negative control. ARS-CPC assay presented the highest optical density in 0.3 µg/mL BMP-2 and 50 µg/mL P28, while the highest intensity of ARS was observed in C2C12 cultured with CS/HAp/BMP-2 and CS/HAp/P28 scaffolds compared to the negative controls. The osteoconductive capability of this delivery system was then investigated through a rat femoral condyle defect model, where the new bone mineral density and the bone volume increased for all CS/HAp scaffolds compared to the collagen sponge control treatment. The histological assessment showed a favourable bone regeneration efficacy of the CS/HAp/P28 compared to the CS/HAp/BMP-2 treatment, thus showing the use of CS/HAp scaffolds with P28 as a promising osteoinductive scaffold for bone healing applications.","PeriodicalId":18398,"journal":{"name":"Micro & Nano Letters","volume":"34 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86921324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intramolecular OHO Hydrogen Bonding in Dibenzoylmethane Enol: Raman Spectroscopic and Quantum Chemical Study","authors":"B. Kolesov, E. Pritchina, Aleksey Ya. Tikhonov","doi":"10.3390/micro3010009","DOIUrl":"https://doi.org/10.3390/micro3010009","url":null,"abstract":"In the present work, the intramolecular O-H···O hydrogen bonding in 3-hydroxy-1,3-diphenylprop-2-en-1-one (keto-enol form of dibenzoylmethane, DBM) was investigated. For this purpose, the Raman spectra of polycrystalline samples of ordinary (H-DBM) and deuterated (D-DBM) 3-hydroxy-1,3-diphenylprop-2-en-1-one in the temperature range of 5–300 K were measured. It was found that low-temperature hydrogen bonding is extremely strong, the proton and deuteron are located in the midpoint of the O···O segment, and their ground and first excited vibrational states are located above the barrier U0 between the local minima. The vibrational frequencies, in this case, are 1543 and 1709 cm−1 for the proton and 1045 and 1087 cm−1 for the deuteron. As the temperature rises and the barrier height increases in H-DBM, the zero-point vibrational state of the proton begins to move into one of the local minima at T > 50 K, while the excited state remains in the broad single-well potential. The same is observed in D-DBM, but with a significant temperature delay. Compounds with donor (−OCH3) and acceptor (−NO2) substituents in the phenyl ring were also synthesized and their spectra were obtained. Both results confirm existing ideas about the nature of the extremely strong hydrogen bond. The quantum-chemical calculation of the vibrational spectrum of H-DBM and D-DBM is consistent with the experimental results.","PeriodicalId":18398,"journal":{"name":"Micro & Nano Letters","volume":"288 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79401779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sensitivity enhancement for micromechanical vibro-impact resonators using snap-through curved beams","authors":"Yun Yi,&nbsp;Chun-Pu Tsai,&nbsp;Wei-Chang Li","doi":"10.1049/mna2.12155","DOIUrl":"https://doi.org/10.1049/mna2.12155","url":null,"abstract":"<p>This work enhances the driving sensitivity of micromechanical vibro-impact resonators by reducing the output switching gap. Differing from previous works for gap narrowing that either require a dedicated pull-in bias voltage and stopper structures or post-fabrication refill processes, the use of the snap-through technique calls for only the initial activation step without the need for constantly applied voltage or additional process steps. Doing so realizes a final gap spacing from a typical 2-μm limitation to a 0.9-μm sub-micron gap. While probes are used to mechanically initiate the bistable transition in this proof-of-concept demonstration, this could be done electrically once properly designed actuation electrodes are available. This transducer gap narrowing technique can help facilitate higher sensitivity for vibro-impact resonator embedded applications such as zero-quiescent power communication receivers.</p>","PeriodicalId":18398,"journal":{"name":"Micro & Nano Letters","volume":"18 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/mna2.12155","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50142752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrated Characterization of Mudstones in the Andes of Colombia: Understanding Its Complexities for Risk Mitigation","authors":"German Alfonso Reyes-Mendoza, J. Henao-Martínez, Eduardo Castro Marín","doi":"10.3390/micro3010007","DOIUrl":"https://doi.org/10.3390/micro3010007","url":null,"abstract":"This article presents a comprehensive vision of particularities and constraints of the Paja Formation in the Northern Andes of Colombia, supported by personal, institutional, and academic experiences, including a doctoral thesis in completion (geomorphology and risks research line). Such fine-grained marine rocks cause severe damage in diverse zones, with little spread, and are very unfavorable, especially within the Eastern Cordillera (departments of Santander and Cundinamarca), whose socio-environmental problems motivated a popular legal action in the municipality of Vélez due to the cracking and collapse of houses, damage to roads and landslides in the urban area, as well as flows, subsidence, and high hydrogeochemical dynamism or rare earths, although they also presented spontaneous ignition at the rural area. Understanding how these problems originate and interrelate is the main objective of the work. At the beginning, we include some brief definitions, terms, and key approaches to understand the consolidated geomaterials, location, and background of the problem; then, the results of meso–macro–micro studies, obtained by combining the field techniques and conventional instrumental laboratory analyses (tests on the chemistry of water and soil, description of samples with magnifying glasses, petrography with a polarized light microscope, micromorphology of regoliths–colluvions) of nanoscientists (emphasizing RXD-RXF, SEM, IR-Raman spectroscopy, TOC-TS) are presented. These characterizations and new knowledge must be socially and institutionally appropriated and applied in land use planning and risk management for the sustainability of challenging environments with the stratiforms of Lower Cretaceous rocks and associated Quaternary deposits in populated mountainous areas and contrasting intertropical hydroclimatological regimes, geologically active, so unstable and insecure.","PeriodicalId":18398,"journal":{"name":"Micro & Nano Letters","volume":"38 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85323447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transferrin-Grafted Albumin Nanoparticles for the Targeted Delivery of Apocynin and Neuroprotection in an In Vitro Model of the BBB","authors":"Venkatesan Perumal, Arunreddy Ravula, Agnieszka Agas, M. Kannan, Xiangshan Liu, Shanmuga Sundari I, S. Vijayaraghavalu, J. Haorah, Yuanwei Zhang, N. Chandra","doi":"10.3390/micro3010008","DOIUrl":"https://doi.org/10.3390/micro3010008","url":null,"abstract":"Traumatic brain injury (TBI) is a major cause of morbidity and mortality worldwide, affecting over 10 million people annually, with an estimated cost of $76.5 billion. Although apocynin freely transverses the blood–brain barrier (BBB), its application is limited due to its rapid elimination, low terminal half-life (t1/2 = 6.7 min), narrow dose–response relationship, and cytotoxicity, thereby requiring repeated dosages. With this study, we aimed to develop transferrin-functionalized nanoparticles encapsulating apocynin to treat neuroinflammation for targeted drug delivery to sites of brain injury. As a preliminary approach, we endeavored to optimize the formulation parameters of apocynin-loaded albumin nanoparticles prepared through the desolvation method. The nanoparticles were characterized for their size, polydispersity, surface charge, drug loading and in vitro drug release. In this study, we also investigated the anti-inflammatory and neuroprotective effects of free apocynin and nanoparticle-loaded apocynin in neuronal cells. We show that the developed formulation displayed monodispersed, nanosized particles with higher entrapment efficiency, loading, stability, and sustained release profiles. The permeability of the nanoparticles across HBMECs reached the maximum at 67%. The in vivo evaluation revealed the enhanced uptake of transferrin-anchored nanoparticles in the brain tissues when compared with unmodified nanoparticles after I.V. administration. In vivo nanoparticle localization studies using a blast TBI (bTBI) model and confocal fluorescence microscopy have shown that tf-apoANPs are successful in delivering relatively high amounts of nanoparticles to the brain parenchyma and glial cells compared to non-targeted nanoparticles. We also establish that targeted nanoparticles accumulate in the brain. In conclusion, tf-apoANPs are efficacious carriers for targeted delivery across the blood–brain barrier to potentially treat neuroinflammation in brain injury and other diseases.","PeriodicalId":18398,"journal":{"name":"Micro & Nano Letters","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88303865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}