Nanomaterials

Metal chalcogenides such as copper zinc tin sulfide (CZTS) have been intensively studied as potential photovoltaic cell materials, but their viability have been marred by crystal defects and low open circuit potential (V_oc) deficit, which affected their energy conversion efficiency. Strategies to improve on the properties of this material such as alloying with other elements have been explored and have yielded promising results. Here, we report the synthesis of CZTS and the partial substitution of S with Te via anion hot injection synthesis method to form a solid solution of a novel kesterite nanomaterial, namely, copper zinc tin sulfide telluride (CZTSTe). Particle-size analyzed via small angle X-ray scattering spectroscopy (SAXS) confirmed that CZTS and CZTSTe materials are nanostructured. Crystal planes values of 112, 200, 220 and 312 corresponding to the kesterite phase with tetragonal modification were revealed by the X-ray diffraction (XRD) spectroscopic analysis of CZTS and CZTSTe. The Raman spectroscopy confirmed the shifts at 281 cm⁻¹ and 347 cm⁻¹ for CZTS, and 124 cm⁻¹, 149 cm⁻¹ and 318 cm⁻¹ for CZTSTe. High degradation rate and the production of hot electrons are very detrimental to the lifespan of photovoltaic cell (PVC) devices, and thus it is important to have PVC absorber layer materials that are thermally stable. Thermogravimetric analysis (TGA) analysis indicated a 10% improvement in the thermal stability of CZTSTe compared to CZTS at 650 °C. With improved electrical conductivity, low charge transfer resistance (R_ct) and absorption in the visible region with a low bandgap energy (E_g) of 1.54 eV, the novel CZTSTe nanomaterials displayed favorable properties for photovoltaics application. Full article

Controlled deposition of metals is essential for the creation of bimetallic catalysts having predictable composition and character. Continuous co-electroless deposition (co-ED) permits the creation of bimetallic catalysts with predictive control over composition. This method was applied to create a suite of Cu–Pt mixed-metal shell catalysts for use in methanol electrooxidation in direct methanol fuel cell applications (DMFCs). Enhanced performance of Cu–Pt compositions over Pt alone was predicted by existing computational studies in the literature. Experimental evidence from this study supports the bifunctional catalyst explanation for enhanced activity and confirms the optimum Cu:Pt ratio as Cu₃Pt for this methanol electrooxidation. This ability to control the composition of a bimetallic shell can be extended to other systems where the ratio of two metals is critical for catalytic performance. Full article

In the last few decades, the combination between nanotechnology and nutraceutics has gained the attention of several research groups. Nutraceuticals are considered as active compounds, abundant in natural products, showing beneficial effects on human health. Unfortunately, the uses, and consequently the health benefits, of many nutraceutical products are limited by their unsuitable chemico-physical features. For example, many nutraceuticals are characterized by low water solubility, low stability and high susceptibility to light and oxygen, poor absorption and potential chemical modifications after their administration. Based on the potential efficacy of nutraceuticals and on their limiting features, nanotechnology could be considered a revolutionary innovation in empowering the beneficial properties of nutraceuticals on human health, thus enhancing their efficacy in several diseases. For this reason, nanotechnology could represent a new frontier in supplementary food. In this review, the most recent nanotechnological approaches are discussed, focusing on their ability to improve the bioavailability of the most common nutraceuticals, providing an overview regarding both the advantages and the possible limitations of the use of several nanodelivery systems. In fact, although the efficacy of smart nanocarriers in improving health benefits deriving from nutraceuticals has been widely demonstrated, the conflicting opinions on the mechanism of action of some nanosystems still reduce their applicability in the therapeutic field. Full article

The application of nanoparticles in consumer products and nanomedicines has increased dramatically in the last decade. Concerns for the nano-safety of susceptible populations are growing. Due to the small size, nanoparticles have the potential to cross the placental barrier and cause toxicity in the fetus. This review aims to identify factors associated with nanoparticle-induced fetotoxicity and the mechanisms involved, providing a better understanding of nanotoxicity at the maternal–fetal interface. The contribution of the physicochemical properties of nanoparticles (NPs), maternal physiological, and pathological conditions to the fetotoxicity is highlighted. The underlying molecular mechanisms, including oxidative stress, DNA damage, apoptosis, and autophagy are summarized. Finally, perspectives and challenges related to nanoparticle-induced fetotoxicity are also discussed. Full article

Both ionic and nanoparticle iron have been proposed as materials to control multidrug-resistant (MDR) bacteria. However, the potential bacteria to evolve resistance to nanoparticle bacteria remains unexplored. To this end, experimental evolution was utilized to produce five magnetite nanoparticle-resistant (FeNP_1–5) populations of Escherichia coli. The control populations were not exposed to magnetite nanoparticles. The 24-h growth of these replicates was evaluated in the presence of increasing concentrations magnetite NPs as well as other ionic metals (gallium III, iron II, iron III, and silver I) and antibiotics (ampicillin, chloramphenicol, rifampicin, sulfanilamide, and tetracycline). Scanning electron microscopy was utilized to determine cell size and shape in response to magnetite nanoparticle selection. Whole genome sequencing was carried out to determine if any genomic changes resulted from magnetite nanoparticle resistance. After 25 days of selection, magnetite resistance was evident in the FeNP treatment. The FeNP populations also showed a highly significantly (p < 0.0001) greater 24-h growth as measured by optical density in metals (Fe (II), Fe (III), Ga (III), Ag, and Cu II) as well as antibiotics (ampicillin, chloramphenicol, rifampicin, sulfanilamide, and tetracycline). The FeNP-resistant populations also showed a significantly greater cell length compared to controls (p < 0.001). Genomic analysis of FeNP identified both polymorphisms and hard selective sweeps in the RNA polymerase genes rpoA, rpoB, and rpoC. Collectively, our results show that E. coli can rapidly evolve resistance to magnetite nanoparticles and that this result is correlated resistances to other metals and antibiotics. There were also changes in cell morphology resulting from adaptation to magnetite NPs. Thus, the various applications of magnetite nanoparticles could result in unanticipated changes in resistance to both metal and antibiotics. Full article

Extensive bone defect repair remains a clinical challenge, since ideal implantable scaffolds require the integration of excellent biocompatibility, sufficient mechanical strength and high biological activity to support bone regeneration. The inorganic nanomaterial-based therapy is of great significance due to their excellent mechanical properties, adjustable biological interface and diversified functions. Calcium–phosphorus compounds, silica and metal-based materials are the most common categories of inorganic nanomaterials for bone defect repairing. Nano hydroxyapatites, similar to natural bone apatite minerals in terms of physiochemical and biological activities, are the most widely studied in the field of biomineralization. Nano silica could realize the bone-like hierarchical structure through biosilica mineralization process, and biomimetic silicifications could stimulate osteoblast activity for bone formation and also inhibit osteoclast differentiation. Novel metallic nanomaterials, including Ti, Mg, Zn and alloys, possess remarkable strength and stress absorption capacity, which could overcome the drawbacks of low mechanical properties of polymer-based materials and the brittleness of bioceramics. Moreover, the biodegradability, antibacterial activity and stem cell inducibility of metal nanomaterials can promote bone regeneration. In this review, the advantages of the novel inorganic nanomaterial-based therapy are summarized, laying the foundation for the development of novel bone regeneration strategies in future. Full article

Controllable growth of wafer-scale in-plane nanowires (NWs) is a prerequisite for achieving addressable and scalable NW-based quantum devices. Here, by introducing molecular beam epitaxy on patterned Si structures, we demonstrate the wafer-scale epitaxial growth of site-controlled in-plane Si, SiGe, and Ge/Si core/shell NW arrays on Si (001) substrate. The epitaxially grown Si, SiGe, and Ge/Si core/shell NW are highly homogeneous with well-defined facets. Suspended Si NWs with four {111} facets and a side width of about 25 nm are observed. Characterizations including high resolution transmission electron microscopy (HRTEM) confirm the high quality of these epitaxial NWs. Full article

The monitoring of Na⁺ ions distributed in the body has been indirectly calculated by the detection of Na⁺ ions in urine. We fabricated a two–dimensional (2D) Na⁺ ion sensor using a graphene ion–sensitive field–effect transistor (G–ISFET) and used fluorinated graphene as a reference electrode (FG–RE). We integrated G–ISFET and FG on a printed circuit board (PCB) designed in the form of a secure digital (SD) card to fabricate a disposable Na⁺ ion sensor. The sensitivity of the PCB tip to Na⁺ ions was determined to be −55.4 mV/dec. The sensor exhibited good linearity despite the presence of interfering ions in the buffer solution. We expanded the evaluation of the PCB tip to real human patient urine samples. The PCB tip exhibited a sensitivity of −0.36 mV/mM and linearly detected Na⁺ ions in human patient urine without any dilution process. We expect that G–ISFET with FG–RE can be used to realize a disposable Na⁺ ion sensor by serving as an alternative to Ag/AgCl reference electrodes. Full article

This experimental study aims to examine the partial discharge (PD) properties of palm oil and coconut oil (CO) based aluminum oxide (Al₂O₃) nanofluids with and without surfactants. The type of surfactant used in this study was sodium dodecyl sulfate (SDS). The volume concentrations range of Al₂O₃ dispersed in oil samples was varied from 0.001% to 0.05%. The ratio of surfactants to nanoparticles was set to 1:2. In total, two different types of refined, bleached and deodorized palm oil (RBDPO) and one type of CO were measured for PD. Mineral oil (MO) was also examined for comparison purpose. PDIV measurements for all samples were carried out based on rising voltage method whereby a needle-sphere electrode configuration with a gap distance of 50 mm was chosen in this study. Al₂O₃ improves the PDIVs of RBDPO, CO and MO whereby the highest improvements of PDIVs are 34%, 39.3% and 27%. The PD amplitude and repetition rate of RBDPO improve by 38% and 81% while for CO, it can increase up to 65% and 80% respectively. The improvement of PD amplitude and repetition rate for MO are 18% and 95%, regardless with and without SDS. Without SDS, the presence of Al₂O₃ could cause 26%, 75% and 65% reductions of the average emission of light signals for RBDPOA, RBDPOB and CO with the improvement of PD characteristics but both events do not correlate at the same volume concentration of Al₂O₃. On the other hand, the average emission of light signal levels of the oils increases with the introduction of SDS. The emission of light signal in MO does not correlate with the PD characteristics improvement either with or without SDS. Full article

Rational design and development of the electrodes with high-mass loading yet maintaining the excellent electrochemical properties are significant for a variety of electrochemical energy storage applications. In comparison with the slurry-casted electrode, herein, a hierarchically porous activated carbon (HPAC) electrode with higher mass loading (8.3 ± 0.2 mg/cm²) is successfully prepared. The pouch-type symmetric device (1 cell) with the propylene carbonate-based electrolyte shows the rate capability (7.1 F at 1 mA/cm² and 4.8 F at 10 mA/cm²) and the cycling stability (83% at 12,000 cycles). On the other hand, an initial discharge capacitance of 32.4 F and the capacitance retention of 96% after 30,000 cycles are delivered from a pouch-type symmetric supercapacitor (five cells). The corresponding electrochemical performances are attributed to the fascinating properties of the HPAC and the synergistic features of the resulting electrode. Full article

Cyclic adenosine monophosphate (cAMP) is an important research target because it activates protein kinases, and its signaling pathway regulates the passage of ions and molecules inside a cell. To detect the chemical reactions related to the cAMP intracellular signaling pathway, cAMP, adenosine triphosphate (ATP), adenosine monophosphate (AMP), and adenosine diphosphate (ADP) should be selectively detected. This study utilized single-molecule quantum measurements of these adenosine family molecules to detect their individual electrical conductance using nanogap devices. As a result, cAMP was electrically detected at the single molecular level, and its signal was successfully discriminated from those of ATP, AMP, and ADP using the developed machine learning method. The discrimination accuracies of a single cAMP signal from AMP, ADP, and ATP were found to be 0.82, 0.70, and 0.72, respectively. These values indicated a 99.9% accuracy when detecting more than ten signals. Based on an analysis of the feature values used for the machine learning analysis, it is suggested that this discrimination was due to the structural difference between the ribose of the phosphate site of cAMP and those of ATP, ADP, and AMP. This method will be of assistance in detecting and understanding the intercellular signaling pathways for small molecular second messengers. Full article

A metallic nano-trench is a unique optical structure capable of ultrasensitive detection of molecules, active modulation as well as potential electrochemical applications. Recently, wet-etching the dielectrics of metal–insulator–metal structures has emerged as a reliable method of creating optically active metallic nano-trenches with a gap width of 10 nm or less, opening a new venue for studying the dynamics of nanoconfined molecules. Yet, the high surface tension of water in the process of drying leaves the nano-trenches vulnerable to collapsing, limiting the achievable width to no less than 5 nm. In this work, we overcome the technical limit and realize metallic nano-trenches with widths as small as 1.5 nm. The critical point drying technique significantly alleviates the stress applied to the gap in the drying process, keeping the ultra-narrow gap from collapsing. Terahertz spectroscopy of the trenches clearly reveals the signature of successful wet etching of the dielectrics without apparent damage to the gap. We expect that our work will enable various optical and electrochemical studies at a few-molecules-thick level. Full article

Over the past decades, there has been a growing interest in using natural molecules with therapeutic potential for biomedical applications. In this context, our aim is focused on anthocyanins (AN) as molecules with anticancer properties that could be used in melanoma local therapies. Due to their susceptibility to environmental changes, current study is based on the design and development of a fluorescent system for carrying and trafficking AN inside melanoma cells. The architectural structure of the proposed system CaCO₃(PAH)@[email protected] reflects a spherical shape, 1080 nm diameter and a solid groundwork CaCO₃(PAH), on which rhodamine B isothiocyanate (RBITC) fluorophore was firstly added; then, poly(acrylic acid) (PAA) polyelectrolytes and poly(allylamine hydrochloride) (PAH) were successfully deposited. Purified AN from chokeberries were entrapped between PAA layers (rate of 94.6%). In vitro tests confirmed that CaCO₃(PAH)@[email protected] does not affect the proliferation of melanoma B16-F10 cells and proved that their internalization and trafficking can be followed after 24 h of treatment. Data presented here could contribute not only to the existing knowledge about the encapsulation technology of AN but also might bring relevant information for a novel formula to deliver therapeutic molecules or other bio-imaging agents directly into melanoma cells, a strategy that could positively improve tumor therapies. Full article

We present a detailed study about the substrate-induced strain and thickness effects on the structure and magnetic properties of La_0.5Sr_0.5CoO₃ films. The in-plane tensile or compressive strain imposed by four different substrates configures an in-plane or out-of-plane easy axis, respectively. The presence of a soft magnetic phase at the interface is also conditioned by the type of strain. The obtained results are discussed in terms of the different anisotropies that participate and control the final magnetic behavior. The relevance of these results lies in the feasibility of La_0.5Sr_0.5CoO₃ in memory applications and spintronic devices. Full article

Nanoparticles (NPs) are promising platforms for the development of diagnostic and therapeutic tools. One of the main hurdle to their medical application and translation into the clinic is the fact that they accumulate in the spleen and liver due to opsonization and scavenging by the mononuclear phagocyte system. The “protein corona” controls the fate of NPs in vivo and becomes the interface with cells, influencing their physiological response like cellular uptake and targeting efficiency. For these reasons, the surface properties play a pivotal role in fouling and antifouling behavior of particles. Therefore, surface engineering of the nanocarriers is an extremely important issue for the design of useful diagnostic and therapeutic systems. In recent decades, a huge number of studies have proposed and developed different strategies to improve antifouling features and produce NPs as safe and performing as possible. However, it is not always easy to compare the various approaches and understand their advantages and disadvantages in terms of interaction with biological systems. Here, we propose a systematic study of literature with the aim of summarizing current knowledge on promising antifouling coatings to render NPs more biocompatible and performing for diagnostic and therapeutic purposes. Thirty-nine studies from 2009 were included and investigated. Our findings have shown that two main classes of non-fouling materials (i.e., pegylated and zwitterionic) are associated with NPs and their applications are discussed here highlighting pitfalls and challenges to develop biocompatible tools for diagnostic and therapeutic uses. In conclusion, although the complexity of biofouling strategies and the field is still young, the collective data selected in this review indicate that a careful tuning of surface moieties is a pivotal step to lead NPs through their future clinical applications. Full article

The biomedical translational applications of functionalized nanoparticles require comprehensive studies on their effect on human stem cells. Here, we have tested neat star-shaped mesoporous silica nanoparticles (s-MSN) and their chemically functionalized derivates; we examined nanoparticles (NPs) with similar dimensions but different surface chemistry, due to the amino groups grafted on silica nanoparticles (s-MSN-NH₂), and gold nanoseeds chemically adsorbed on silica nanoparticles (s-MSN-Au). The different samples were dropped on glass coverslips to obtain a homogeneous deposition differing only for NPs’ chemical functionalization and suitable for long-term culture of human Bone Marrow–Mesenchymal stem cells (hBM-MSCs) and Adipose stem cells (hASCs). Our model allowed us to demonstrate that hBM-MSCs and hASCs have comparable growth curves, viability, and canonical Vinculin Focal adhesion spots on functionalized s-MSN-NH₂ and s-MSN-Au as on neat s-MSN and control systems, but also to show morphological changes on all NP types compared to the control counterparts. The new shape was stem-cell-specific and was maintained on all types of NPs. Compared to the other NPs, s-MSN-Au exerted a small genotoxic effect on both stem cell types, which, however, did not affect the stem cell behavior, likely due to a peculiar stem cell metabolic restoration response. Full article

Gallium telluride (GaTe) one-dimensional (1D) and two-dimensional (2D) materials have drawn much attention for high-performance optoelectronic applications because it possesses a direct bandgap for all thickness. We report the morphology-controlled vapor phase growth of 1D GaTe nanowires and 2D GaTe nanosheets by a simple physical vapor transport (PVT) approach. The surface morphology, crystal structure, phonon vibration modes, and optical property of samples were characterized and studied. The growth temperature is a key synthetic factor to control sample morphology. The 1D GaTe single crystal monoclinic nanowires were synthesized at 550 °C. The strong interlayer interaction and high surface migration of adatoms on c-sapphire enable the assembly of 1D nanowires into 2D nanosheet under 600 °C. Based on the characterization results demonstrated, we propose the van der Waals growth mechanism of 1D nanowires and 2D nanosheets. Moreover, the visible-light photocatalytic activity of 1D nanowires and 2D nanosheets was examined. Both 1D and 2D GaTe nanostructures exhibit visible-light active photocatalytic activity, suggesting that the GaTe nanostructures may be promising materials for visible light photocatalytic applications. Full article

Nanocomposites comprising high-density polyethylene (HDPE) and boehmite (BA) nanoparticles were prepared by melt blending and subsequently irradiated with electrons. Electron irradiation of HDPE causes crosslinking and, in the presence of BA, generates ketone functional groups. The functional groups can then form hydrogen bonds with the hydroxyl groups on the surface of the BA. Additionally, if the BA is surface modified by vinyltrimethoxysilane (vBA), it can covalently bond with the HDPE by irradiation-induced radical grafting. The strong covalent bonds generated by electron beam irradiation allow the desirable properties of the nanofiller to be transferred to the rest of the nanocomposite. Since EB irradiation produces a great number of strong covalent bonds between vBA nanoparticles and HDPE, the modulus of elasticity, yield strength, and resistance to thermal shrinkage are enhanced by electron irradiation. Full article

Good stability and reproducibility are important factors in determining the place of any material in their respective field and these two factors also enable them to use in various applications. At present, transition metal carbides (TMCs) have high demand either in the two-dimensional (2D) form (MXene) or as nanocomposites, nanoparticles, carbide films, carbide nano-powder, and carbide nanofibers. They have shown good stability at high temperatures in different environments and also have the ability to show adequate reproducibility. Metal carbides have shown a broad spectrum of properties enabling them to engage the modern approach of multifacet material. Several ways have been routed to synthesize metal carbides in their various forms but few of those gain more attention due to their easy approach and better properties. TMCs find applications in various fields, such as catalysts, absorbents, bio-sensors, pesticides, electrogenerated chemiluminescence (ECL), anti-pollution and anti-bacterial agents, and in tumor detection. This article highlights some recent developments in the synthesis methods and applications of TMCs in various fields. Full article