Cell Applications Research Articles

Effect of synthesis methods on dielectric performance of ZnO nanoparticles

ABSTRACT Zinc oxide (ZnO) nanoparticles are widely studied for the application of dye-sensitised solar cells (DSSCs). The control of nanoscale morphology and microstructural properties of ZnO is critical for DSSCs performance. The current study provides an insight about the effect of synthesis methods (i.e. co-precipitation and sol–gel) on structural, optical and electrical properties of ZnO nanoparticles. The formation of hexagonal wurtzite phase with space group P63mc was confirmed by Rietveld fitted X-ray diffraction and Raman spectroscopy. The variation in morphology due to different synthesis methods was confirmed by Scanning electron microscopy. Functional groups were identified by Fourier transform infrared spectroscopy. The presence of defects led to the narrowing of band gap of ZnO nanoparticles, and was confirmed by diffuse reflectance spectroscopy. The frequency-dependent dielectric behaviour was explained by means of Maxwell–Wagner–Sillars model. The current study paves the way of potential application of ZnO nanoparticles in DSSCs.

Automating Laboratory Processes by Connecting Biotech and Robotic Devices—An Overview of the Current Challenges, Existing Solutions and Ongoing Developments

The constantly growing interest and range of applications of advanced cell, gene and regenerative therapies raise the need for efficient production of biological material and novel treatment technologies. Many of the production and manipulation processes of such materials are still manual and, therefore, need to be transferred to a fully automated execution. Developers of such systems face several challenges, one of which is mechanical and communication interfaces in biotechnological devices. In the present state, many devices are still designed for manual use and rarely provide a connection to external software for receiving commands and sending data. However, a trend towards automation on the device market is clearly visible, and the communication protocol, Open Platform Communications Data Access (OPC DA), seems to become established as a standard in biotech devices. A rising number of vendors offer software for device control and automated processing, some of which even allow the integration of devices from multiple manufacturers. The high, application-specific need in functionalities, flexibility and adaptivity makes it difficult to find the best solution and, in many cases, leads to the creation of new custom-designed software. This report shall give an overview of existing technologies, devices and software for laboratory automation of biotechnological processes. Furthermore, it presents an outlook for possible future developments and standardizations.

Morphological alterations, activity, mRNA fold changes, and aging changes before and after orthodontic force application in young and adult human-derived periodontal ligament cells.

The response of periodontal ligament cells (PDLC) from adult subjects in comparison to those obtained from younger ones to mechanical forces has been a matter of interest recently because of induced senescent changes. This study evaluated and compared cell surface changes and activity, integrin beta 1, and β-actin mRNA fold changes as well as klotho protein secretion capabilities of PDLC from young and adult donors before and after subjecting to orthodontic forces. A total of 40 subjects with bimaxillary dentoalveolar protrusion requiring extraction of first premolars for orthodontic treatment were selected and divided into two groups. Force ranging from 80 to 90 g was applied to maxillary first premolars and extraction was carried out at two different time periods-pre-treatment (control group) and 28 days after force application (experimental group). Periodontal ligament was obtained, and cell surface changes and activity were observed with atomic force microscopy (AFM) and fluorescent tagging. mRNA fold change of integrin beta-1 and β-actin mRNA, as well as beta-galactosidase assay, was performed, and levels of klotho protein were evaluated. AFM nanoindentation and fluorescent tagging indicated increased surface morphological changes in younger cells compared to adult ones. We observed a decrease in integrin beta 1 but an increase in β-actin mRNA levels in PDLC obtained from younger subjects compared to adults, while an increase was observed in SA-β-GAL from adult cells. The level of klotho protein was lower in adult cells in comparison to younger ones. Large sample studies are required to find out a variation in aging characteristics between young and adult PDLC. The study observed significant differences between PDLC obtained from younger and adult subjects in response to orthodontic force application.

Dendrimer applications: a brief review

: Dendrimers are highly branched three-dimensional macromolecules with a highly controlled structure, a single molecular weight, numerous controllable dendritic branches and peripheral functionalities, as well as the tendency to adopt an ellipsoid or spheroid shape once a certain size is reached. These features have made them attractive for application in pharmaceutical and medicinal chemistry in gene transfection, as medical imaging agents, and as drug carriers in potential drug delivery agents. The incorporation of metallic species into dendritic molecules has also been reported; the focus has been on organometallic dendrimers with metallic species only at specific positions of the molecules, such as the core, dendritic branches and the periphery, studied for their magnetic, electronic, and photo-optical or catalytic properties. Dendrimers have been investigated for optoelectronic applications (adsorption, emission, laser emission, nonlinear optics) through the encapsulation of active units by dendritic branches, core and peripheral. This review briefly discusses their use in nanomedicine, cancer treatment, treatment of other diseases, tissue repair, catalysis and applications in OLEDs and solar cells.

A novel coumarin-based pyrazoline fluorescent probe for detection of Fe3+ and its application in cells

A novel coumarin-based pyrazoline fluorescent probe A was synthesized through a four-step reaction. The structure was characterized by 1H NMR(Nuclear magnetic resonance), 13C NMR and HR-ESI-MS(High resolution electrospray ionization mass spectrometry). The optical properties of the fluorescent probe was investigated by UV–vis absorption and fluorescence emission spectra. The results showed that the addition of Fe3+ makes the fluorescence emission spectra of A quenched and displayed a linear fluorescence response to Fe3+ with a detection limit of 1.01 × 10−7 M. It also shows good reversibility upon addition of EDTA(Ethylene diamine tetraacetic acid). The structure of the fluorescent probe was optimized by DFT(Density functional theory) calculations, and the binding mechanism between the fluorescent probe and the recognition ion was explained. Moreover, the probe also has practical application in cell imaging.

Versatile Mesoporous Nanoparticles for Cell Applications.

Mesoporous silica nanostructures are emerging as a promising platform able to deal with challenges of many different applications in fields such as biomedicine and nanotechnology. The versatile physical and functional properties of these materials like high specific surface area, ordered porosity, chemical stability under temperature and pH variations, and biocompatible performance, offers new approaches to many biomedical applications ranging from drug delivery systems to biosensing, cell applications and tissue engineering. Their morphology, size and textural properties can be easily tailored by means of chemical control, giving rise to a variety of nanostructures with hexagonal (SBA15, MCM41) or cubic (SBA16) arrangement of channels and pore size ranging from 1.3 to 10 nm. Based on the versatility of their silane surface, a plethora of hybrid mesoporous matrices can be prepared incorporating new functionalities like contrast enhancement for magnetic resonance imaging, magnetic/plasmonic hyperthermia, drug delivery or cell applications by the simple grafting of superparamagnetic metal oxides (Fe₃O₄, transition metal ferrites) nanoparticles, noble metal (Au, Ag) nanoparticles, fluorescent moieties (fluorescein, rhodamine) or biological agents (mAb, mRNA, etc). The goal of this work is to present the development, by a facile soft template method, of size tailored mesoporous silica nanospheres from 20 to 350 nm (by means of chemical control), and highlight its versatility for surface grafting (with rhodamine and polydopamine) and their biological compatibility and efficient uptake by cultured HeLa cells. The combined, physicochemical and biological, properties indicate that MSNs are good candidates for cell tagging, gene transfer or targeted therapies.

Investigation of optoelectronic properties of AgIn1−xGaxY2 (Y = Se, Te) semiconductors

The electronic structure and optical properties of AgIn1−xGaxY2 (Y = Se, Te) are investigated using first-principles calculations based on density functional theory. Both the local density approximation (LDA) and generalized gradient approximation (GGA) are employed in the calculation. The crystal structure of ternary semiconductors is the tetragonal chalcopyrite structure with space group $${\text{I}}\overline{{4}} {\text{2d}}$$ . The lattice parameters a(A) and c(A) are found to vary with the change in Ga composition. The energy gap across the Fermi level in the density of states plots shows that these materials are semiconductors. To compute accurate energy gap values, the LDA + U method is adopted. The calculated elastic constants indicate that these compounds are mechanically stable at normal pressure. The semiconducting nature of these materials may prove their applications in solar cells and photovoltaic absorbers. The optical parameters such as dielectric function, electron energy loss function, refractive index and reflectivity are computed.

Tunable room temperature ferromagnetism and optical bandgap of CdS:Er nanoparticles

A semiconductor compound, which portrays ferromagnetism with tunable optical and photoluminescence properties after a sensible doping of suitable dopant, is vital for modern spintronic and luminescent applications. In this sense, we fabricate CdS, Cd0.98Er0.02S, and Cd0.96Er0.04S nanoparticles (NPs) via an inexpensive co-precipitation way. No structural deformation was found in cubic CdS after Er (III) doping. The as-fabricated NPs demonstrated good crystallinity as well as slight changes in sizes varying 3 nm–7 nm. An X-ray photoelectron spectroscopy results confirmed that the impure-free nature of the prepared samples. A decreasing trend in the optical band gap was found by the increase in the doping level. The 1CdS NPs showed diamagnetic character, whereas the Er (III)-doped CdS NPs exhibited frail ferromagnetic character at room temperature, which slightly increased as a function of Er (III) concentration. Based on the literature, this is the initial magnetic report on the CdS:Er system and this will be very informative for the further magnetic investigations on the Er doping. Hence, the tunable optical and ferromagnetic magnetic properties of CdS:Er NPs demonstrated in this work may be beneficial for optoelectronic, solar cell and spintronic applications.

Equivalent Electrical Circuit Modeling of CNT-Based Transparent Electrodes

Among the various applications of carbon nanotubes (CNTs) that have been investigated since the discovery of their exceptional potential in the electronic field, great interest has been directed towards the creation of carbon-based materials capable of replacing Indium Tin Oxide (ITO) as a transparent electrode. Such transparent conductive films find application in touch panels, LCD screens, OLED displays, photovoltaic cells, and many others. This review presents a collection of techniques that have been proposed during the last decade for the modeling of carbon nanotube-based materials by means of equivalent electrical networks. These networks represent the electrical properties of CNT-based conductive thin films in a way that can be easily included in circuit simulators for the simulation-assisted design of the different devices under static and dynamic conditions.

Applications of graphene for energy harvesting applications: Focus on mechanical synthesis routes for graphene production

ABSTRACT This paper introduces a comprehensive overview of various graphene production and deposition processes with a main focus on their utilization for energy harvesting and augmentation applications. A focused view on simple yet effective mechanical exfoliation techniques to produce graphene, and sometimes simultaneously deposit it. Two of these techniques, i.e. ball milling technique and compressed air blasting of graphite have been used and developed in our labs, respectively. The produced and deposited graphene via these methods is tested for energy harvesting enhancement in applications such as the spectral absorption enhancement of solar thermal collectors, electrode production for capacitive deionization, and as Nano-spacers in SERS applications for solar PV cells with an increase in 28% compared with Pt-based counterelectrode. The two mechanical production processes of graphene discussed are facile, economical and rapid, and is expected to bring solid-state graphene production a step closer to automation, a concept that is currently synonymous only with solution-based processes. These processes enabled the incorporation of a graphene layer on solar thermal collectors and this layer has exhibited 43% enhancement in efficiency than ones that did not have a graphene layer. Because of graphene eminence and its well-established place in many areas one of them being energy this is due to its unique thermal, mechanical, optical, electronic, and chemical properties. This paper will analyze the tools used for the synthesis of graphene and their throughput, cost and ease of use.

Study of perovskite CH3NH3PbI3 thin films under thermal exposure

Methyl-ammonium lead iodide-based perovskite materials have been extensively studied for applications in solar cells, which have reached high efficiencies of about 24% in the laboratory. However, being a hybrid (organic–inorganic) material, methyl-ammonium lead iodide can be affected by climatic conditions, such as humidity, light and temperature. While perovskite films have been synthesized, and annealing as part of the fabrication process has been reported, there have been, however, relatively few studies on the effects of temperature when the films, after synthesis, have been intentionally exposed to different temperatures. In this work, a study of the behaviour of perovskite films (MAPbI3) has been conducted exposing the films to different temperatures (25, 40, 50, 60 and 70°C) in small greenhouses. Homogeneous perovskite films were deposited by the anti-solvent method. The films were characterized by field-emission scanning electron microscopy, X-ray diffraction and optical absorption. The effects of temperature on film morphology, grain size and light absorbance are reported.

Controlled Manipulation and Active Sorting of Particles Inside Microfluidic Chips Using Bulk Acoustic Waves and Machine Learning.

Manipulation of cells, droplets, and particles via ultrasound within microfluidic chips is a rapidly growing field, with applications in cell and particle sorting, blood fractionation, droplet transport, and enrichment of rare or cancerous cells, among others. However, current methods with a single ultrasonic transducer offer limited control of the position of single particles. In this paper, we demonstrate closed-loop two-dimensional manipulation of particles inside closed-channel microfluidic chips, by controlling the frequency of a single ultrasound transducer, based on machine-vision-measured positions of the particles. For the control task, we propose using algorithms derived from the family of multi-armed bandit algorithms. We show that these algorithms can achieve controlled manipulation with no prior information on the acoustic field shapes. The method learns as it goes: there is no need to restart the experiment at any point. Starting with no knowledge of the field shapes, the algorithms can (eventually) move a particle from one position inside the chamber to another. This makes the method very robust to changes in chip and particle properties. We demonstrate that the method can be used to manipulate a single particle, three particles simultaneously, and also a single particle in the presence of a bubble in the chip. Finally, we demonstrate the practical applications of this method in active sorting of particles, by guiding each particle to exit the chip through one of three different outlets at will. Because the method requires no model or calibration, the work paves the way toward the acoustic manipulation of microparticles inside unstructured environments.

Synthesis and characterization of C60 and C70 acetylacetone monoadducts and study of their photochemical properties for potential application in solar cells

We report on the synthesis of C60 and C70 monoadducts at room temperature through the Bingel reaction; employing acetylacetone as ligand; in presence of DBU (1,8-Diazabicyclo [5.4.0] undec-7-ene), carbon tetrabromide (CBr4), and o-dichlorobenzene. Diacetylmethane-[C60-Ih]-fullerene-[5,6] and diacetylmethane-[C70-D5h]-fullerene-[5,6] monoadducts were obtained with yields of 69% and 44%, respectively. The products were purified by column chromatography (CC, on silica gel, using hexane, carbon disulfide, and chloroform as eluents at room temperature) and characterized by Nuclear Magnetic Resonance (1H and 13C), Fourier-Transform Infrared (FT-IR) and UV-Visible spectroscopies, Matrix-assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) Mass spectrometry, Cyclic Voltammetry (CV), and Osteryoung Square Wave Voltammetry (OSWV). Both compounds showed irreversible reduction peaks controlled by diffusion, with LUMO energy levels of -3.09 eV, -3.13 eV for C60, and C70 monoadducts, respectively. These values are comparable with the -3.99 eV of PC61BM. The synthetized adducts were incorporated into inverted-type perovskite solar cells and were used as electron transporting materials (ETM) obtaining power conversion efficiencies (PCE) of 8.5% and 14.0% for the C60 and C70 monoadducts, respectively. When C60 is replaced by a lower symmetrical fullerene such as C70 an improved light absorption in the visible region is observed.

Automatic 1D 1H NMR Metabolite Quantification for Bioreactor Monitoring.

High-throughput metabolomics can be used to optimize cell growth for enhanced production or for monitoring cell health in bioreactors. It has applications in cell and gene therapies, vaccines, biologics, and bioprocessing. NMR metabolomics is a method that allows for fast and reliable experimentation, requires only minimal sample preparation, and can be set up to take online measurements of cell media for bioreactor monitoring. This type of application requires a fully automated metabolite quantification method that can be linked with high-throughput measurements. In this review, we discuss the quantifier requirements in this type of application, the existing methods for NMR metabolomics quantification, and the performance of three existing quantifiers in the context of NMR metabolomics for bioreactor monitoring.

Matrix-Assisted Bone Marrow Stimulation: A Surgical Technique

Background: Microfracture is an established technique for cartilage regeneration but is limited by many factors such as small defect size, intralesional osteophytes, and lower quality of cartilage regeneration. Therefore, methods to improve results after microfracture like additional matrix augmentation or autologous cell addition are promising techniques. An all-arthroscopic surgical technique for matrix-augmented bone marrow stimulation will be presented here. Indications: Cartilage lesions of moderate size (>1 cm2) that appear too large or unsuitable for pure microfracture but do not yet meet the criteria for autologous cartilage transplantation (>2.5 cm2). The exact size of suitable lesions is currently evolving with only few evidence-based data available. Technique Description: The arthroscopic procedure largely follows the standard microfracture technique. First, the cartilage defect is extensively debrided with removal of calcific cartilage layer. Stable cartilage margins have to be created with removal of all unstable fragments. The resulting well-defined defect is then measured with the use of a marking probe. The subchondral bone is then penetrated and opened using a microfracture awl. Next, the matrix based on hyaluronic acid (Hyalofast) is cut to the appropriate size. All joint fluid is removed, and the matrix is inserted through a previously placed canula and modeled into the defect with the probe. When the defect is well contained, no other fixation material is necessary. Otherwise, the matrix can be additionally fixed using fibrin clue. Cell application (dependent on regulatory issues) can be performed. Before closure, the joint should be moved to ensure safe fixation of the matrix. Results: Currently, there are only insufficient data to exactly define the defect size for microfracture or matrix-assisted bone marrow stimulation. Some studies show an advantage of using biomaterials compared with microfracture alone, but further studies are necessary. Discussion/Conclusion: The presented arthroscopic matrix-assisted bone marrow stimulation is a technically simple, inexpensive way of treating cartilage defects and should therefore be considered when treating affected patients. It can be used in a variety of joints. An additional combination with bone marrow–derived mesenchymal stem cells might be promising but is subject to country-specific regulatory issues.

Simultaneous and quantitative monitoring transcription factors in human embryonic stem cell differentiation using mass spectrometry-based targeted proteomics.

Human embryonic stem cells (hESCs) can be self-propagated indefinitely in culture while holding the capacity to generate almost all cell types. Although this powerful differentiation ability of hESCs has become a potential source of cell replacement therapies, application of stem cells in clinical practice relies heavily on the exquisite control of their developmental fate. In general, an essential first step in differentiation is to exit the pluripotent state, which is precariously balanced and depends on a variety of factors, mainly centering on the core transcriptional mechanism. To date, much evidence has indicated that transcription factors such as Sox2, Oct4, and Nanog control the self-renewal and pluripotency of hESCs. Their expression displays a restricted spatial-temporal pattern and their small changes in level can significantly affect directed differentiation and the cell type derived. So far, few assays have been developed to monitor this process. Herein, we provided a mass spectrometry (MS)-based approach for simultaneous and quantitative monitoring of these transcription factors, in an attempt to provide insight into their contributions in hESC differentiation.

Application of Cell, Tissue, and Biomaterial Delivery in Cardiac Regenerative Therapy.

Cardiovascular diseases (CVD) are the leading cause of death around the world, being responsible for 31.8% of all deaths in 2017 (Roth, G. A. et al. The Lancet 2018, 392, 1736-1788). The leading cause of CVD is ischemic heart disease (IHD), which caused 8.1 million deaths in 2013 (Benjamin, E. J. et al. Circulation 2017, 135, e146-e603). IHD occurs when coronary arteries in the heart are narrowed or blocked, preventing the flow of oxygen and blood into the cardiac muscle, which could provoke acute myocardial infarction (AMI) and ultimately lead to heart failure and death. Cardiac regenerative therapy aims to repair and refunctionalize damaged heart tissue through the application of (1) intramyocardial cell delivery, (2) epicardial cardiac patch, and (3) acellular biomaterials. In this review, we aim to examine these current approaches and challenges in the cardiac regenerative therapy field.

Electronic and optical properties of Y-doped $$\hbox {BaBiO}_{3}$$

We investigate the nature of bond disproportionation in $$\hbox {BaBi}_{0.9}\hbox {Y}_{0.1}\hbox {O}_{3}$$ (BYBO) and its manifestation in the valence band and the optical absorption spectra. Our room-temperature (RT) structural results show that both the parent and the doped (BYBO) compounds stabilise in monoclinic structure but with a change in space group from I2/m to P21/n on Y doping. The Raman scattering studies suggest decrement in the breathing mode distortion of $$\hbox {BiO}_{6}$$ octahedra. The valence band spectra show an increase in the gap and close to the Fermi edge, we observe significant modifications in the fine structures on Y doping. These were studied using band structure calculations under TB-mBJ. The results show that the electronic states of the Y ions play significant role in driving the electronic structure. We also observe the importance of O 2p holes and also transfer of electrons from O 2p to Bi1 6s, Bi2 6s, and Y states to bring about bond disproportionation in the doped compound. The intensity variations and the features in the optical absorption spectra were understood based on the E vs k point calculations performed in the irreducible part of the Brillouin zone. The behaviour of the gap on doping is also in line with the calculations and optical absorption studies. The behaviour of the optical absorption spectra suggests possible use in solar cell and optical sensor applications. A composite of the doped compound with $$\hbox {BaTiO}_{3}$$ may find applications in the field of high-energy density capacitor. We believe that our results will be helpful in understanding the role of the electronic states of the dopants in superconductivity, especially in comparison with the monoclinic phase exhibited in the superconducting phase of $$\hbox {BaPb}_{0.75}\hbox {Bi}_{0.25}\hbox {O}_{3}$$ .

Guest-Host Interactions in Symmetrical Carboxy Heptamethine Cyanine Dyes-Titanium Dioxide Systems: Synthesis, Theoretical Calculations, Aggregation Properties, and Application in Dye-Sensitized Solar Cells

In this work, the role of deoxycholic acid (DCA) as a coadsorbent was investigated in the sensitization of mesoporous TiO2 layers (host) with symmetrical carboxy heptamethine cyanine dyes (guest). Different approaches have been tested, aimed at reducing the H-aggregation and minimizing the competition between cyanine molecules and DCA for active sites of the host, thus improving solar cell efficiency. Heptamethine cyanines containing carboxylic anchoring groups were obtained with good yields. The cyanines present UV-Vis absorption in methanol and dimethylformamide solutions ascribed to fully allowed electronic transitions ( 1 π π ∗ ), as well as fluorescence emission in the NIR region, with any evidence of aggregations in both ground and excited states. TD-DFT calculations were also performed in order to study the geometry and charge distribution of these compounds in their ground and excited electronic states. Solid-state photophysics indicates that the cyanines showed excellent adsorption on TiO2, which can be justified by the presence of the -COOH moieties in the structure. Photophysical measurements have revealed the best concentrations of dye and DCA, which resulted in efficient inhibition of cyanine H-aggregates on the TiO2 surface in addition to allow large dye loading. HOMO and LUMO energy levels of the dyes were identified by cyclic voltammetry, showing oxidation and reduction potentials within acceptable limits for application as a photosensitizer in dye-sensitized solar cells (DSSCs) based on a TiO2 mesoporous photoanode. Assembled DSSCs have shown a large improvement of the electrical parameters and efficiency when a balance between dye aggregation and the competition to the host active sites was reached.

Cucurbit[10]uril-Encapsulated Cationic Porphyrins with Enhanced Fluorescence Emission and Photostability for Cell Imaging.

Porphyrins are widely applied for imaging, diagnosis, and treatment of diseases because of their excellent photophysical properties. However, porphyrins easily tend to aggregate driven by hydrophobic interaction and π-π stacking in an aqueous medium, which causes fluorescence quenching of the porphyrins as well as limitation of cell uptake and intracellular accumulation. Herein, cucurbit[10]uril (CB[10]) was used to fully encapsulate cationic porphyrin (CPor) in the large cavity with strong binding affinity in aqueous solutions, and the CPor aggregates were efficient disassembled, companying remarkable enhancing its fluorescence intensity. The CB[10]-based host-guest complex provided excellent protection to CPor, resulting in less susceptibility to oxidation and imparting higher photostability to CPor for cell imaging. In addition, by complexation with CB[10], it was found that the fluorescence signals and photostability of CPor were also effectively improved in cells with different reactive oxygen species levels. It is highly anticipated that the large macrocyclic host cavity-triggered large-guest encapsulation strategy in this work will provide a convenient and efficient method for designing supramolecular porphyrin dyes, thus broadening the diagnosis and imaging application in cells and microorganisms.