The phase evolution of reactive radio frequency (RF) magnetron sputtered Cr0.28Zr0.10O0.61 coatings has been studied by in situ synchrotron X-ray diffraction during annealing under air atmosphere and vacuum. The annealing in vacuum shows t-ZrO2 formation starting at ∼750–800 °C, followed by decomposition of the α-Cr2O3 structure in conjunction with bcc-Cr formation, starting at ∼950 °C. The resulting coating after annealing to 1140 °C is a mixture of t-ZrO2, m-ZrO2, and bcc-Cr. The air-annealed sample shows t-ZrO2 formation starting at ∼750 °C. The resulting coating after annealing to 975 °C is a mixture of t-ZrO2 and α-Cr2O3 (with dissolved Zr). The microstructure coarsened slightly during annealing, but the mechanical properties are maintained, with no detectable bcc-Cr formation. A larger t-ZrO2 fraction compared with α-Cr2O3 is observed in the vacuum-annealed coating compared with the air-annealed coating at 975 °C. The results indicate that the studied pseudo-binary oxide is more stable in air atmosphere than in vacuum.

A nanoparticle-based drug delivery system is first established by mesoporous silica encapsulating amino acid–intercalated layered double hydroxide (LDH) to construct nanocomposites AA-LDH@MS. The amino acids including phenylalanine (Phe) and histidine (His) with aromatic groups are intercalated into LDH as the cores Phe-LDH and His-LDH. These nanocomposites AA-LDH@MS display multispaces of the interlayer spaces of LDH and porous channels of mesoporous silica to load drugs. Moreover, amino acid molecules provide the interaction sites to improve effectively loading amounts of drugs. 5-Fluorouracil (5-FU) is used as the cargo molecules to observe the delivery in vitro. The results indicate that the maximum loading amounts of drugs are up to 392 mg/g at 60 °C for 12 h in the nanocomposite Phe-LDH@MS. All the nanocomposites exhibit the sustained release of 5-FU at pH 4 and pH 7.4. The Korsmeyer–Peppas model is used to fit the kinetic plot of the drug release in vitro, which concludes that 5-FU release from AA-LDH@MS belongs to Fickian diffusion.

Scaffolds based on two different geometries were constructed by additive manufacturing: one based on a triply periodic minimal surface, the Schwarz D surface, and the other based on a rectangular geometry with orthogonal through-holes. For construction of the scaffolds, two different materials were used: polylactic acid (PLA) in filament form and alumina in printable paste form. The structure of the resulting scaffolds was characterized via X-ray diffraction and scanning electron microscopy, and cell proliferation was assessed for each geometry and material, using fluorescence microscopy and DNA quantification via NanoDrop. Additive manufacturing allowed us to obtain scaffolds with the assessed materials while guaranteeing the interconnectivity of the pores in each one. The curved surfaces constructed with PLA were more favorable for cell attachment and proliferation of the CHO-K1 cell line.

Magnesium (Mg) alloys have received considerable attention as favorable orthopedic implant materials. However, their uncontrolled degradation in the physiological environment has led to premature implant failure. Thus, to address this problem, the present study was focused on developing protective monolayer coatings of fluorine-doped hydroxyapatite (FHA) and a bilayer coating of FHA and poly(lactic acid) (FHA–PLA) on AZ31 Mg. The synthesis involved microwave irradiation which helped in rapid synthesis of FHA coatings and spin coating for developing the PLA layer. Results revealed the formation of dense and defect-free FHA–PLA hybrid coatings. Importantly, they helped in significant reduction of galvanic–corrosion reactions of AZ31 in a physiological medium. The corrosion current density of FHA/PLA–coated samples was about two orders of magnitude lower than uncoated samples. Their lower weight losses further confirmed the coatings’ corrosion resistance. Combined, the as-synthesized FHA–PLA coatings can provide favorable corrosion protection to AZ31 Mg.

Fabrication of simulated buccal mucosa could minimize sacrificing the animals (rabbits and pigs) to extract buccal mucosa for in vitro testing of buccal formulations. Novel artificial buccal mucosa was fabricated using eggshell membrane, extracted from poultry egg, and bovine submaxillary mucin. Chitosan oligosaccharide (COS)–based blended films were fabricated using solvent casting technique. Patches of equal dimensions were cut precisely from whole film. COS-based blended patches were analyzed for their physicochemical and mechanical properties. These patches, proposed to be used for buccal drug delivery, were tested for their mucoadhesion timing using the artificial mucosal membrane. The COS–PVA–blended patch displayed better mucoadhesion than chitosan oligosaccharide–alginate–blended film with the fabricated simulated buccal mucosa. Novel buccal mucosa mimetic–surface such as the one reported in this research article could prove to be a very useful tool in minimizing the use of excised animal buccal mucosa for mucoadhesion testing of buccal drug delivery formulations. Novel COS-blended films were fabricated as a proposed mucoadhesive buccal drug delivery vehicle.

Until recently, mesoporous silica (MPS) particles have been successfully used in various biomedical applications including drug delivery. In the past decades, the research on MPS shifted sharply to gene delivery owing to its biocompatible, mesoporous structure that allows for loading oligonucleotides, shielding in the bloodstream, and delivering them to patient cells’ cytoplasm to stop cells’ genetic transcription. Until now, researchers faced several unique challenges and MPS, as oligonucleotide vectors, could not reach the clinical stage. In this study, material-related challenges were endeavored to overcome by a combined particle synthesis/oligo-loading strategy. DNA-encapsulated silica/polyethylene glycol (PEG) hybrid xerogels were synthesized at one step, via sol–gel technique. The xerogels were grinded into particles and characterized by X-ray diffraction, scanning electron microscopy, ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, and gas adsorption analysis. The results demonstrated that uniform oligo-loaded silica/PEG hybrid xerogels could be synthesized without surface modification. Oligonucleotides were encapsulated inside the whole porous network, rather than attached only to particle surfaces as such in the conventional route. The results showed that PEG incorporation led to formation of monolithic xerogels, which could be grinded into spherical particles (557 ± 110 nm) with well-defined edges. Due to grinding, PEG chains were present both in the interior and on the surface of the particles. 10% PEG incorporation into silica precursor (tetraethyl orthosilicate) increased the resistance of DNA-encapsulated silica against protein degradation. In the overall sol–gel-derived silica/PEG hybrid materials were revealed as potential candidates for gene delivery applications such as RNA interference therapies.

Bioactive glass–ceramic powder reinforced alginate scaffold has been successfully prepared and characterized for bone tissue engineering application. Glass-ceramic (GC) particles were synthesized through a sol–gel process. Alginate scaffolds containing different weight percentages of GC were fabricated through a freeze-drying technique. The composite scaffolds were characterized for phase analysis through X-ray powder diffraction and microstructure analysis through field emission scanning electron microscopy. The swelling behavior, degradation behavior, bioactivity, cell adhesion, and osteogenic potential of the fabricated scaffolds were evaluated. Microstructural analysis showed a highly porous behavior of the scaffold having a macroporous pore size. The composite scaffolds showed good bioactivity where GC induces apatite formation. The compressive strength of the scaffold was enhanced with GC addition due to the reinforcement of the alginate matrix. In vitro cell studies revealed that the composite scaffolds promoted cell adhesion, proliferation, and osteogenesis. Fabricated scaffolds are a promising biomaterial candidate for bone substitution because of their attractive properties.

Sputtered thin films of Ag2ZnSnS4 (AZTS) have shown promising semiconducting properties in spite of the films containing SnS2, SnSx, or ZnS as impurity phases. In this study, reaction pathways were identified to produce single-phase AZTS nanoparticles as precursors for forming dense, single-phase films. The morphology, composition, and phase evolution during nanoparticle formation in an oleylamine-based solvothermal reaction process were determined using surface-enhanced Raman spectroscopy (SERS) and transmission and scanning transmission electron microscope (TEM/STEM). The reaction pathways for AZTS nanoparticles were found to be different from Cu2ZnSnS4 nanoparticles in oleylamine, which may explain the difficulty in creating (Ag, Cu)2ZnSnS4 solid solutions in the nanoparticle synthesis. The single-phase AZTS nanoparticle films have a band gap (2.16 eV) slightly higher than sputtered films, and photoelectrochemical (PEC) measurements demonstrated a current of 0.1 mA/cm2 in K2SO4 solution even as porous nanoparticle films, suggesting the potential of this material in solar energy conversion when converted into a dense film.

Perovskite chalcogenides are gaining substantial interest as an emerging class of semiconductors for optoelectronic applications. High-quality samples are of vital importance to examine their inherent physical properties. We report the successful crystal growth of the model system, BaZrS3 and its Ruddlesden–Popper phase Ba3Zr2S7 by a flux method. X-ray diffraction analyses showed the space group of Pnma with lattice constants of a = 7.056(3) Å, b = 9.962(4) Å, and c = 6.996(3) Å for BaZrS3 and P42/mnm with a = 7.071(2) Å, b = 7.071(2) Å, and c = 25.418(5) Å for Ba3Zr2S7. Rocking curves with full width at half maximum of 0.011° for BaZrS3 and 0.027° for Ba3Zr2S7 were observed. Pole figure analysis, scanning transmission electron microscopy images, and electron diffraction patterns also establish the high quality of the grown crystals. The octahedral tilting in the corner-sharing octahedral network is analyzed by extracting the torsion angles.

Multifunctional antifogging (AF) coatings consisting of alternating layers of positively charged ZrO2 nanoparticles (NPs) and negatively charged SiO2 NPs were rapidly fabricated via spray-spin-blow layer-by-layer electrostatic assembly followed by calcination. The resultant coatings of only three bilayers exhibited excellent AF, superhydrophilic, antireflective (AR), and self-cleaning (SC) properties, as well as high mechanical stability. These were demonstrated by various methods, e.g., transmission and scanning electron microscopy, X-ray diffraction, UV-Vis spectrometry, a contact angle test, a boiling test (constant 100 °C), a low-temperature test, and mechanical stability tests. ZrO2 and SiO2 NPs were synthesized and utilized as building blocks for fabricating the coatings. The resultant coatings exhibited excellent AF and SC properties due to the superhydrophilicity of the coating, showed excellent AR properties due to the quarter-wave coating with a low refractive index, and exhibited excellent superhydrophilic properties due to a rough microtextured surface. The simplicity of the fabrication process, easy availability of the nanomaterials, and excellent adhesion to substrates for the coating preparation might make the low-cost, nontoxic, and eco-friendly multifunctional coatings potentially useful in optical and display devices.

In this study, cast tungsten carbide particle/steel matrix surface composites were fabricated using a vacuum evaporative pattern casting (V-EPC) infiltration process. Through thermal shock tests at 500 °C, the initiation and propagation of cracks at the interface of the composites were investigated. Owing to the mismatch in the coefficients of thermal expansion (CTE), cracks tended to appear at the interface reaction zone (IRZ) between the particles and the matrix. Because there was also a difference in the CTE between the composite and the substrate, the cracks propagated rapidly along the transition layer (TL) between the composite and the substrate, and finally connected to form macro-cracks. Based on the stress analysis and calculation, the maximum thermal stress at the TL was 63.4 MPa, while the maximum thermal stress at the IRZ was 38 MPa. It could thus be inferred that the TL is the weak link under thermal fatigue. In addition, the experimental results were verified and found to be in good agreement with the calculations.

Composites of 0–20 vol% Ti-coated cBN (cBN@Ti) particles dispersed in WC–Ni were densified by spark plasma sintering under 50 MPa at 1300 °C. The cBN particles were distributed homogeneously with a Ti-rich interfacial layer between the cBN particles and WC–Ni matrix. Increasing cBN@Ti to 20 vol% decreased the sample densification, but all the composites were still >97.5% dense. The Vickers hardness and flexural strength initially increased and then decreased, reaching the maximum values of 1820 HV10 with 15 vol% cBN@Ti and 1500 MPa with 5 vol% cBN@Ti, respectively, whereas the fracture toughness KIC gradually increased from 8 to 13 MPa m1/2. For cutting rocks, the wear significantly decreased with 5–15 vol% cBN@Ti but increased with 20 vol% cBN@Ti because of cBN particles pull-out.

Mo, Zr, and Y with low diffusion coefficients in Al matrix were used to improve the high-temperature properties of the Al–5.8Cu–0.3Mn–0.2Mg alloy. The effects of these microalloying elements on the microstructures of the Al–5.8Cu–0.3Mn–0.2Mg alloy were investigated with the aid of optical microscopy and high-resolution transmission electron microscope (HRTEM). The HRTEM images and selected area electron diffraction patterns indicated that L12-Al3(Zr, Y), Al3Zr, Al3Y, and Al12Mo could precipitate in the process of solid solution treatment after adding Mo, Zr, and Y. These Mo-, Zr-, and Y-containing precipitates were stable at high temperatures and could slow the coarsening rate of θ′ precipitates at high temperatures. The tensile strength of the Al–5.8Cu–0.3Mn–0.2Mg alloy modified by Mo, Zr, and Y microalloying elements was improved significantly at both room and high temperatures. The strengthening mechanisms were discussed in detail.