Browsing by Subject "221 Nano-technology"

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  • Piironen, Kati; Haapala, Markus; Talman, Virpi; Järvinen, Päivi; Sikanen, Tiina (2020)
    Three-dimensional (3D) printing has recently emerged as a cost-effective alternative for rapid prototyping of microfluidic devices. The feature resolution of stereolithography-based 3D printing is particularly well suited for manufacturing of continuous flow cell culture platforms. Poor cell adhesion or material-induced cell death may, however, limit the introduction of new materials to microfluidic cell culture. In this work, we characterized four commercially available materials commonly used in stereolithography-based 3D printing with respect to long-term (2 month) cell survival on native 3D printed surfaces. Cell proliferation rates, along with material-induced effects on apoptosis and cell survival, were examined in mouse embryonic fibroblasts. Additionally, the feasibility of Dental SG (material with the most favored properties) for culturing of human hepatocytes and human-induced pluripotent stem cells was evaluated. The strength of cell adhesion to Dental SG was further examined over a shear force gradient of 1–89 dyne per cm² by using a custom-designed microfluidic shear force assay incorporating a 3D printed, tilted and tapered microchannel sealed with a polydimethylsiloxane lid. According to our results, autoclavation of the devices prior to cell seeding played the most important role in facilitating long-term cell survival on the native 3D printed surfaces with the shear force threshold in the range of 3–8 dyne per cm².
  • Qi, Shengcai; Zhang, Pengfei; Ma, Ming; Yao, Minghua; Wu, Jinjin; Mäkilä, Ermei; Salonen, Jarno; Ruskoaho, Heikki; Xu, Yuanzhi; Santos, Helder A.; Zhang, Hongbo (2019)
    Nanotechnology employs multifunctional engineered materials in the nanoscale range that provides many opportunities for translational stem cell research and therapy. Here, a cell-penetrating peptide (virus-1 transactivator of transcription)-conjugated, porous silicon nanoparticle (TPSi NP) loaded with the Wnt3a protein to increase both the cell survival rate and the delivery precision of stem cell transplantation via a combinational theranostic strategy is presented. The TPSi NP with a pore size of 10.7 nm and inorganic framework enables high-efficiency loading of Wnt3a, prolongs Wnt3a release, and increases antioxidative stress activity in the labeled mesenchymal stem cells (MSCs), which are highly beneficial properties for cell protection in stem cell therapy for myocardial infarction. It is confirmed that the intracellular aggregation of TPSi NPs can highly amplify the acoustic scattering of the labeled MSCs, resulting in a 2.3-fold increase in the ultrasound (US) signal compared with that of unlabeled MSCs. The translational potential of the designed nanoagent for real-time US imaging-guided stem cell transplantation is confirmed via intramyocardial injection of labeled MSCs in a nude mouse model. It is proposed that the intracellular aggregation of protein drug-loaded TPSi NPs could be a simple but robust strategy for improving the therapeutic effect of stem cell therapy.
  • Terracciano, M; De Stefano, L.; Almeida Santos, Helder; Martucci, N.M.; Ruggiero, I.; Rendina, I.; Migliaccio, N.; Lamberti, A.; Rea, I. (INTECHopen, 2016)
    Diatomite is a natural porous silica material of sedimentary origin, formed by remains of diatom skeletons called “frustules.” The abundance in many areas of the world and the peculiar physico-chemical properties made diatomite an intriguing material for several applications ranging from food production to pharmaceutics. However, diatomite is a material still rarely used in biomedical applications. In this chapter, the properties of diatom frustules reduced to nanoparticles, with an average diameter less than 350 nm, as potential drug vectors are described. Their biocompatibility, cellular uptake, and capability to transport molecules inside cancer cells are discussed. Preliminary studies of in vivo toxicity are also presented.
  • Ruoko, Tero-Petri; Hiltunen, Arto; Iivonen, Tomi; Ulkuniemi, Riina; Lahtonen, Kimmo; Ali-Löytty, Harri; Mizohata, Kenichiro; Valden, Mika; Leskelä, Markku; Tkachenko, Nikolai V. (2019)
    We employ atomic layer deposition to prepare 50 nm thick hematite photoanodes followed by passivating them with a 0.5 nm thick Ta2O5-overlayer and compare them with samples uniformly doped with the same amount of tantalum. We observe a three-fold improvement in photocurrent with the same onset voltage using Ta-overlayer hematite photoanodes, while electrochemical impedance spectroscopy under visible light irradiation shows a decreased amount of surface states under water splitting conditions. The Tadoped samples have an even higher increase in photocurrent along with a 0.15 V cathodic shift in the onset voltage and decreased resistivity. However, the surface state capacitance for the Ta-doped sample is twice that of the reference photoanode, which implies a larger amount of surface hole accumulation. We further utilize transient absorption spectroscopy in the sub-millisecond to second timescale under operating conditions to show that electron trapping in both Ta2O5-passivated and Ta-doped samples is markedly reduced. Ultrafast transient absorption spectroscopy in the sub-picosecond to nanosecond timescale shows faster charge carrier dynamics and reduced recombination in the Ta-doped hematite photoanode resulting in the increased photoelectrochemical performance when compared with the Ta2O5-overlayer sample. Our results show that passivation does not affect the poor charge carrier dynamics intrinsic to hematite based photoanodes. The Ta-doping strategy results in more efficient electron extraction, solving the electron trapping issue and leading to increased performance over the surface passivation strategy.
  • Jahromi, Leila Pourtalebi; Shahbazi, Mohammad-Ali; Maleki, Aziz; Azadi, Amir; Santos, Helder A. (2021)
    Over the past decades, considerable attention has been dedicated to the exploitation of diverse immune cells as therapeutic and/or diagnostic cell-based microrobots for hard-to-treat disorders. To date, a plethora of therapeutics based on alive immune cells, surface-engineered immune cells, immunocytes' cell membranes, leukocyte-derived extracellular vesicles or exosomes, and artificial immune cells have been investigated and a few have been introduced into the market. These systems take advantage of the unique characteristics and functions of immune cells, including their presence in circulating blood and various tissues, complex crosstalk properties, high affinity to different self and foreign markers, unique potential of their on-demand navigation and activity, production of a variety of chemokines/cytokines, as well as being cytotoxic in particular conditions. Here, the latest progress in the development of engineered therapeutics and diagnostics inspired by immune cells to ameliorate cancer, inflammatory conditions, autoimmune diseases, neurodegenerative disorders, cardiovascular complications, and infectious diseases is reviewed, and finally, the perspective for their clinical application is delineated.
  • Hyvönen, Jere; Alonso Serra, Juan; Meriläinen, Antti; Help-Rinta-Rahko, Hanna; Nieminen, Kaisa; Salmi, Ari; Svedström, Kirsi; Helariutta, Yrjö; Haeggström, Edward (IEEE, 2019)
    We have developed a coded excitation scanning acoustic microscope (CESAM) that operates in range of 0.1 to 1 GHz. We used a focusing transducer with 375 MHz central frequency to image two different tree species (birch and hybrid aspen) at different stem height to study their micromechanical difference. The method was able to capture the fresh wood anatomy with cellular resolution. A full stem section scan revealed the heterogeneity of micromechanical properties throughout tissues, and highlighted the higher stiffness of the phloem fibers compared to other vascular cells. This demonstrates the applicability of the method for plant developmental biology.
  • Seppälä, Sanni; Vehkamäki, Marko; Mizohata, Kenichiro; Noh, Wontae; Räisänen, Jyrki; Ritala, Mikko; Leskelä, Markku (2019)
    Three heteroleptic Zr precursors were studied for atomic layer deposition (ALD) of ZrO2. Films were deposited from Zr(Cp)((t)BuDAD)((OPr)-Pr-i), Zr(MeCp)(TMEA), and Zr(Me5Cp)(TEA) with either water or ozone as the oxygen source {tBuDAD = N, N-bis(tertbutyl) ethene-1,2-diaminato, TMEA = tris[2-(methylamino) ethyl]aminate, TEA = triethoanolaminate}. Self-limiting film growth was confirmed for the Zr(Cp)((t)BuDAD)((OPr)-Pr-i)/O-3 process at 250 degrees C and for the Zr(M(e)5Cp)(TEA)/O-3 process at 375 degrees C, which is among the highest temperatures for advanced heteroleptic precursors. Excellent film purity with C, H, and N levels below the detection limit of the elastic recoil detection analysis was obtained with ozone as the oxygen source. All the studied processes showed the same trend that at low deposition temperatures films were tetragonal ZrO2 and at higher temperatures mixtures of tetragonal and monoclinic ZrO2. With water, the monoclinic phase appeared at higher temperatures than with ozone. In addition to the deposition temperature, the film thickness affected the phase; thinner films favored the tetragonal phase and monoclinic peaks were more clearly seen in thicker films. The high thermal stability and excellent film purity show that from the three studied Zr precursors, Zr(Me5Cp)(TEA) is a noteworthy precursor candidate for ALD of ZrO2. Published by the AVS.
  • Benatto, L.; Marchiori, C. F. N.; Talka, T.; Aramini, M.; Yamamoto, N. A. D.; Huotari, S.; Roman, L. S.; Koehler, M. (2020)
    The difference in aggregation size of the C-60 and C-70 fullerenes affect the photovoltaic performance of devices assembled in the so-called bilayer architecture with poly [2,7-(9,9- dioctyl- dibenzosilole)- alt-4,7- bis(thiophen-2-yl)benzo- 2,1,3- thiadiazole] (PSiF-DBT) as the electron donor material. Despite the better performance of the C-70 devices, which is related to the high absorption coefficient in the visible range and the superior charge transport properties, the short-circuit current variation upon annealing treatment at 100 degrees C is approximately twice bigger when the C-60 is the acceptor. We attribute this effect to the tendency of C-60 in form smaller aggregate domains relatively to the C-70. The increased roughness on the polymeric surface after annealing results in an enhanced donor/acceptor contact area and assists the fullerene diffusion deeper inside the polymeric layer. This effect leads to a better mixing between donor and acceptor species and create a interpenetrating layer close to the so-called bulk heterojunction. Since C-60 forms smaller aggregates, this mechanism is more pronounced for this molecule. Therefore, a significant variation in the performance of the C-60 devices is observed after this kind of treatment. Density Functional Theory calculations of the potential energy of interaction between two fullerene molecules and X-Ray measurements gives evidences to support this idea. In addition, combining spectrally resolved external quantum efficiency measurements with optical modeling our results also indicate the occurrence of the bilayer interfacial mixing for PSiF-DBT/C-60.
  • Hakkarainen, Enni; Korkjas, Arle; Laidmae, Ivo; Lust, Andres; Semjonov, Kristian; Kogermann, Karin; Nieminen, Heikki J.; Salmi, Ari; Korhonen, Ossi; Haeggström, Edward; Heinämäki, Jyrki (2019)
    We investigated nozzleless ultrasound-enhanced electrospinning (USES) as means to generate nanofibrous drug delivery systems (DDSs) for pharmaceutical and biomedical applications. Traditional electrospinning (TES) equipped with a conventional spinneret was used as a reference method. High-molecular polyethylene oxide (PEO) and chitosan were used as carrier polymers and theophylline anhydrate as a water-soluble model drug. The nanofibers were electrospun with the diluted mixture (7:3) of aqueous acetic acid (90% v/v) and formic acid solution (90% v/v) (with a total solid content of 3% w/v). The fiber diameter and morphology of the nanofibrous DDSs were modulated by varying ultrasonic parameters in the USES process (i.e., frequency, pulse repetition frequency and cycles per pulse). We found that the USES technology produced nanofibers with higher fiber diameter (402 +/- 127 nm) than TES (77 +/- 21 nm). An increase of a burst count in USES increased the fiber diameter (555 +/- 265 nm) and the variation in fiber size. The slight-to-moderate changes in a solid state (crystallinity) were detected when compared the nanofibers generated by TES and USES. In conclusion, USES provides a promising alternative for aqueous-based fabrication of nanofibrous DDSs for pharmaceutical and biomedical applications.
  • Mattinen, Miika; King, Peter J.; Bruener, Philipp; Leskelä, Markku; Ritala, Mikko (2020)
    Semiconducting 2D materials, such as SnS2, hold great promise in a variety of applications including electronics, optoelectronics, and catalysis. However, their use is hindered by the scarcity of deposition methods offering necessary levels of thickness control and large-area uniformity. Herein, a low-temperature atomic layer deposition (ALD) process is used to synthesize up to 5x5 cm(2)continuous, few-layer SnS(2)films on a variety of substrates, including SiO2/Si, Si-H, different ALD-grown films (Al2O3, TiO2, and Ir), sapphire, and muscovite mica. As a part of comprehensive film characterization, the use of low energy ion scattering (LEIS) is showcased to determine film continuity, coverage of monolayer and multilayer areas, and film thickness. It is found that on sapphire substrate, continuous films are achieved at lower thicknesses compared to the other substrates, down to two monolayers or even less. On muscovite mica, van der Waals epitaxial growth is realized after the post-deposition annealing, or even in the as-deposited films when the growth is performed at 175 to 200 degrees C. This work highlights the importance of the substrate choice for 2D materials and presents a practical low-temperature method for the deposition of high-quality SnS(2)films that may be further evaluated for a range of applications.
  • Vergallo, Cristian; Hafeez, Muhammad Nadeem; Iannotta, Dalila; Santos, Helder A.; D'Avanzo, Nicola; Dini, Luciana; Cilurzo, Felisa; Fresta, Massimo; Di Marzio, Luisa; Christian, Celia (Springer International Publishing AG, 2021)
    Advances in Experimental Medicine and Biology
    Clinical responses and tolerability of conventional nano-carriers (NCs) are sometimes different from those expected in anticancer therapy. Thus, new smart drug delivery systems (DDSs) with stimuli-responsive properties and novel materials have been developed. Several clinical trials demonstrated that these DDSs have better clinical therapeutic efficacy in the treatment of many cancers than free drugs. Composition of DDSs and their surface properties increase the specific targeting of therapeutics versus cancer cells, without affecting healthy tissues, and thus limiting their toxicity versus unspecific tissues. Herein, an extensive revision of literature on NCs used as DDSs for cancer applications has been performed using the available bibliographic databases.
  • Mao, Xiyuan; Cheng, Ruoyu; Zhang, Hongbo; Bae, Jinhong; Cheng, Liying; Zhang, Lu; Deng, Lianfu; Cui, Wenguo; Zhang, Yuguang; Almeida Santos, Helder; Sun, Xiaoming (2019)
    Several images in Figure 3, Figure 4, and Figure S7, Supporting Information, accidentally presented duplicate samples in the original article. The correct figures are presented below. The authors apologize for any inconvenience this may have caused.
  • Abdelrehiem, Dina Ahmed Mosselhy; Virtanen, Jenni Maaret Elina; Kant, Ravi; He, Wei; Elbahri, Mady; Sironen, Tarja (2021)
    Every day, new information is presented with respect to how to best combat the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This manuscript sheds light on such recent findings, including new co-factors (i.e., neuropilin-1) and routes (i.e., olfactory transmucosal) allowing cell entry of SARS-CoV-2 and induction of neurological symptoms, as well as the new SARS-CoV-2 variants. We highlight the SARS-CoV-2 human-animal interfaces and elaborate containment strategies using the same vaccination (i.e., nanoparticle "NP" formulations of the BNT162b2 and mRNA-1273 vaccines) for humans, minks, raccoon dogs, cats, and zoo animals. We investigate the toxicity issues of anti-CoV NPs (i.e., plasmonic NPs and quantum dots) on different levels. Namely, nano-bio interfaces (i.e., protein corona), in vitro (i.e., lung cells) and in vivo (i.e., zebrafish embryos) assessments, and impacts on humans are discussed in a narrative supported by original figures. Ultimately, we express our skeptical opinion on the comprehensive administration of such antiviral nanotheranostics, even when integrated into facemasks, because of their reported toxicities and the different NP parameters (e.g., size, shape, surface charge, and purity and chemical composition of NPs) that govern their end toxicity. We believe that more toxicity studies should be performed and be presented, clarifying the odds of the safe administration of nanotoxocological solutions and the relief of a worried public.
  • Mattinen, Miika; Hatanpää, Timo; King, Peter J.; Meinander, Kristoffer; Mizohata, Kenichiro; Jalkanen, Pasi; Räisänen, Jyrki; Ritala, Mikko; Leskelä, Markku (2019)
    Tungsten disulfide (WS2) is a semiconducting 2D material, which is gaining increasing attention in the wake of graphene and MoS2 owing to its exciting properties and promising performance in a multitude of applications. Herein, the authors deposited WSx thin films by atomic layer deposition using W-2(NMe2)(6) and H2S as precursors. The films deposited at 150 degrees C were amorphous and sulfur deficient. The amorphous films crystallized as WS2 by mild postdeposition annealing in H2S/N-2 atmosphere at 400 degrees C. Detailed structural characterization using Raman spectroscopy, x-ray diffraction, and transmission electron microscopy revealed that the annealed films consisted of small (
  • Väyrynen, Katja; Hatanpää, Timo; Mattinen, Miika; Heikkilä, Mikko; Mizohata, Kenichiro; Meinander, Kristoffer; Räisänen, Jyrki; Ritala, Mikko; Leskelä, Markku (2018)
    In this paper, we introduce a new Co precursor for the atomic layer deposition (ALD) of Co metal and other Co containing materials. CoCl2(TMEDA) (TMEDA = N,N,N ',N '-tetramethylethylenediamine) is a diamine adduct of cobalt(II) chloride that is inexpensive and easy to synthesize, making it an industrially viable precursor. Furthermore, CoCl2(TMEDA) shows good volatility at reasonably low temperatures and is thermally stable up to a temperature of, similar to 300 degrees C. We also present a full ALD study for the deposition of CoO thin films using CoCl2(TMEDA) and water as precursors. The process was investigated within a temperature range of 225-300 degrees C. Saturation of the film growth with respect to both precursor pulse lengths was verified. According to X-ray diffraction, the films were a mixture of hexagonal and cubic CoO. No reflections corresponding to Co3O4 were detected. The hexagonal phase is characteristic to nanomaterials only and is not seen in bulk CoO. The crystal structure of the films could be tuned by temperature, water pulse lengths, and type of substrate material. The films deposited at 275 degrees C exhibited 1:1 Co:O stoichiometry and very high purity. The CoO films could be reduced to Co metal at an exceptionally low temperature of 250 degrees C in 10% forming gas. Continuity of the reduced Co films was improved when the CoO film was deposited on TiN instead of native oxide terminated Si. The Co content of a 50 nm reduced metal film was as high as 95 at. %, with negligible amounts of oxygen and hydrogen.
  • Meriläinen, Antti; Hyvönen, Jere; Salmi, Ari; Haeggström, Edward (IEEE, 2019)
    IEEE International Ultrasonics Symposium
    We developed a synthetic aperture focusing technique (SAFT)-based algorithm to extend the working distance of a traditional scanning acoustic microscopy (SAM) transducer at 400 MHz. This algorithm is used to analyze C-scan images of a USAF 1951 resolution sample that is imaged at 50 μm defocus and at focus. The comparison of these images shows that this method can enhance the resolution of defocused images. Imaging artefacts caused by this method are discussed.
  • Shahbazi, Mohammad-Ali; Ghalkhani, Masoumeh; Maleki, Hajar (2020)
    Herein, the potential of directional freeze-casting techniques as a very generic, green, and straightforward approach for the processing of various functional porous materials is introduced. These materials include 3D monoliths, films, fibers, and microspheres/beads, which are obtained by the assembly of network building blocks originated from cryoassembly of the various aqueous-based systems. The process simply relies on 1) directional freezing of the slurry through contact with a cold surface, 2) maintaining the slurry at the frozen state for a particular time with controlling the freezing parameters and directions, and 3) sublimation of the created ice crystal templates inside the developed structure to translate the ice growth pattern to final porous structure. The materials developed with such a cryogenic process contain a highly complex porous structure, e.g., a hierarchical and well-aligned microstructure in different levels, which renders a high control over the physicochemical and mechanical functionalities. Due to the versatility and controllability of this technique, the process can also be extended for the mimicking of the structures found in natural materials to the bulk materials to assemble bioinspired porous composites with many useful mechanical and physical features. The aim, herein, is to give a brief overview of the recent advances in developing anisotropic porous inorganic, organic, hybrid, and carbonaceous materials with a particular emphasis on materials with biomimicking microstructure using directional ice templating approach and to highlight their recent breakthrough for different high-performance applications.
  • Yaradoddi, Jayachandra; Kontro, Merja Hannele; Ganachari, Sharanabasava V; Sulochana, M.B:; Agsar, Dayanand; Tapaskar, Rakesh; Shettar, Ashok (Springer Nature Switzerland, 2019)
    Since from the past few decades DNA appeared as an excellent molecular building block for the synthesis of nanostructures because of its probable encoded and confirmation intra- and intermolecular base pairing, various case strategies and consistent assembly techniques have been established to manipulate DNA nanostructures to at higher complexity. The capability to develop DNA construction with precise special control has permitted scientists to discover novel applications in many ways, such as scaffold development, sensing applications, nanodevices, computational applications, nanorobotics, nanoelectronics, biomolecular catalysis, disease diagnosis, and drug delivery. The present chapter emphasizes to brief the opportunities, challenges, and future prospective on DNA nanotechnology and its advancements.
  • Chen, Zhijie; Zhang, Feng; Zhang, Hongbo; Cheng, Liang; Chen, Kaizhe; Shen, Jieliang; Qi, Jin; Deng, Lianfu; He, Chuan; Santos, Helder A.; Cui, Wenguo (2021)
    Gene therapy is identified as a powerful strategy to overcome the limitations of traditional therapeutics to achieve satisfactory effects. However, various challenges related to the dosage form, delivery method, and, especially, application value, hampered the clinical transition of gene therapy. Here, aiming to regulate the cartilage inflammation and degeneration related abnormal IL-1 beta mRNA expression in osteoarthritis (OA), the interference oligonucleotides is integrated with the Au nanorods to fabricate the spherical nucleic acids (SNAs), to promote the stability and cell internalization efficiency. Furthermore, the complementary oligonucleotides are grafted onto hyaluronic acid (HA) to obtained DNA-grafted HA ((DNA)HA) for SNAs delivery by base pairing, resulting in significantly improved injectability and bio-stability of the system. After loading SNAs, the constructed (DNA)HA-SNAs system (HA-SNAs) performs a reversible NIR-triggered on-demand release of SNAs by photo-thermal induced DNA dehybridization and followed by post-NIR in situ hybridization. The in vitro and in vivo experiments showed that this system down-regulated catabolic proteases and up-regulated anabolic components in cartilage over extended periods of time, to safeguard the chondrocytes against degenerative changes and impede the continual advancement of OA.
  • Danne, Reinis; Poojari, Chetan; Martinez-Seara, Hector; Rissanen, Sami; Lolicato, Fabio; Rog, Tomasz; Vattulainen, Ilpo (2017)
    Carbohydrates constitute a structurally and functionally diverse group of biological molecules and macromolecules. In cells they are involved in, e.g., energy storage, signaling, and cellcell recognition. All of these phenomena take place in atomistic scales, thus atomistic simulation would be the method of choice to explore how carbohydrates function. However, the progress in the field is limited by the lack of appropriate tools for preparing carbohydrate structures and related topology files for the simulation models. Here we present tools that fill this gap. Applications where the tools discussed in this paper are particularly useful include, among others, the preparation of structures for glycolipids, nanocellulose, and glycans linked to glycoproteins. The molecular structures and simulation files generated by the tools are compatible with GROMACS.