New Strategy for Creating TiO2 Thin Films with Embedded Au Nanoparticles

This paper proposes a new strategy for producing thin films of TiO2 with embedded gold nanoparticles (TiO2/AuNP). One of the main tasks was the synthesis of a stable dispersion of TiO2 and gold nanoparticles in an aqueous solution of ethylene glycol, suitable for inkjet printing—ink with complex gold nanoparticles (AuCNP ink). The AuCNP were synthesized by a reduction from tetrachloroauric acid in the presence of TiO2 nanoparticles and ethylene glycol (EG). The final formation of TiO2/AuNP films occurred during the annealing of AuCNP layers, inkjet printed on a glass substrate. The TiO2/AuNP films demonstrate absorbance in the yellow-green range due to the localized surface plasmon resonance (LSPR) and are promising for solar cell application.

Properties and Colorimetric Performance of Screen-Printed Thermochromic/UV-Visible Fluorescent Hybrid Ink Systems

In the present research, properties and performance of special effect printing inks were observed with the aim of obtaining a printed product with dual functional properties. Thermochromic liquid crystal-based printing ink (TLC) and UV-visible (daylight invisible) fluorescent inks (UVF), pure and as hybrid ink systems, were printed using a screen-printing technique on two types of uncoated paper substrates. Characterization of the paper substrates was performed, as well as detailed analysis of printed layers. Thickness, surface roughness, surface free energy, and adhesion parameters of printed layers were analysed. Spectral reflectance of pure UVF and TLC printing inks, as well as the spectral reflectance of the proposed hybrid ink systems were measured. The thermochromic effect of the TLC ink and hybrid systems was analysed. Microscopy was used to display the visual colour play effect and the effect of the fluorescence. Results of the measurements showed high compatibility of used materials in the proposed hybrid ink systems. Since the effect of luminescence and the colour play effect in the hybrid systems were preserved, it can be concluded that TLC/UVF hybrid ink systems can find their application in the development of functional packaging and in all other applications with special requirements for temperature monitoring and hidden information for different products.

3D printed bone-like biopolymer composites inspired by nacre

<p>Bone tissue engineering and synthetic biomineralization are two widely researched areas, the principles of which have been combined from time to time in efforts to develop replacement materials for natural bone grafts. Nacre has been studied as a prospective bone graft material owing to its mechanical strength being comparable to that of natural bone. The extraordinary mechanical strength of nacre is attributed to its nanostructure. The McGrath research group developed a synthetic biomineralization method, herein called the McGrath method, that can be used to effectively replicate the elements of nacre’s nanostructure in 2D biopolymer systems in laboratory conditions. Here, the applicability of the McGrath method in translating the calcium carbonate-based mineralization achieved in 2D films onto 3D printed chitosan hydrogel-based scaffolds is investigated. Thereby, enabling the fabrication of 3D chitosan-calcium carbonate composites with properties sought in the context of prospective load-bearing bone grafts. In this work, considering the importance of interconnected porosity in an in vivo environment, nozzle extrusion-based 3D printing was employed to develop 3D structures with interconnected macropores, essentially imitating the porous structure of bone. The applicability of chitosan hydrogels as the printing ink in a custom-designed 3D printer was evaluated and quantified through rheological studies. The printing parameters and an appropriate experimental protocol were devised to fabricate stable 3D chitosan hydrogel-based scaffolds featuring physically crosslinked-layered structure with interconnected macropores. The effect of various drying techniques on retaining this porous structure in dried scaffolds and their swelling behaviour when soaked in a physiologically relevant solvent were explored using various techniques including cryo-scanning electron microscopy. The strategies required to mineralize the as-fabricated 3D chitosan hydrogel-based scaffolds via the McGrath method, such that the mineralization achieved within the 3D scaffolds is similar to that obtained within 2D films, were elucidated. This included the use of polyacrylic acid (PAA), a crystal growth modifier. PAA has previously been shown to be important in achieving a pancake-like calcium carbonate formation, comprised of laterally growing nanoparticle aggregates which form in association with the organic matrix, in 2D films; such structures are observed in the early stages of nacre formation. By modulating the period of exposure of the 3D scaffolds to the mineralization solutions and the concentrations of these solutions, it was found that 3D composites with up to 40% calcium carbonate content and varying crystal morphology could be fabricated using this mineralization method. Importantly, it was observed that the calcium carbonate crystallites were intricately associated with the organic hydrogel matrix. This is another essential element observed in biomineral systems. Various techniques such as scanning electron microscopy (SEM), thermogravimetric analysis (TGA), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) were employed for structural and compositional characterisation of the final composites. The prospect of fabricating 3D chitosan-calcium carbonate composites via a single-step method using chitosan hydrogel preloaded with calcium carbonate crystallites as the printing ink in our custom-designed 3D printer was also investigated. This method was studied as a faster and less labour-intensive alternative to developing composites via the two-step method devised in this research whereby 3D hydrogel-based scaffolds are printed first and then mineralized via the McGrath method. The advantages and disadvantages of the two fabrication techniques are compared. The two-step fabrication method was found to be superior in terms of the properties explored and desired in the composite. The behaviour of the chitosan hydrogel-based scaffolds and composites fabricated using the McGrath method, under different stress and strain regimes were also investigated. Mechanical tests performed on air-dried chitosan hydrogel-based scaffolds and composites showed that the compressive modulus, strength and indentation hardness values obtained were within the same order of magnitude as that of trabecular bone. Data from uniaxial compression tests showed that the yield, ultimate strength and compressive modulus of the 3D scaffolds vary with the total mineral content, morphology and size of the resultant crystallites in the composite. Composites with very low mineral content (~7% CaCO₃ content) showed the best mechanical properties under uniaxial compressive stress (approximately 0.37 GPa compressive modulus, 26 MPa yield strength, and 31 MPa ultimate strength). Nanoindentation tests showed that the nanoscale hardness and indentation modulus increased upon mineralization of the scaffolds but did not vary significantly as a function of the extent of mineralization. Dynamic mechanical analysis showed that the scaffolds (both mineralized and non-mineralized) can effectively dissipate stress without complete fracture when subjected to dynamic compressions within physiologically relevant loading frequencies (1 - 15 Hz) irrespective of the mineral content. The individual responses vary with loading frequency. Having ascertained the structural and mechanical attributes of the fabricated materials, their capacity to enable osteoblast cell attachment and proliferation was explored. Alamar Blue assay and confocal microscopy performed at various time points for samples exposed to in vitro cultured osteoblasts showed that chitosan hydrogel-based scaffolds and composites are biologically non-toxic and facilitate cell adhesion and proliferation. Furthermore, when osteoblasts were incubated with composites with low CaCO₃ content, the number of cells increased significantly within 14 days. The results of this research confirm that 3D printed chitosan hydrogel-based composites fabricated using the McGrath mineralization method featuring various structural and compositional imitations of bone and nacre shows considerable potential as future bone grafts materials.</p>

3D printed bone-like biopolymer composites inspired by nacre

<p>Bone tissue engineering and synthetic biomineralization are two widely researched areas, the principles of which have been combined from time to time in efforts to develop replacement materials for natural bone grafts. Nacre has been studied as a prospective bone graft material owing to its mechanical strength being comparable to that of natural bone. The extraordinary mechanical strength of nacre is attributed to its nanostructure. The McGrath research group developed a synthetic biomineralization method, herein called the McGrath method, that can be used to effectively replicate the elements of nacre’s nanostructure in 2D biopolymer systems in laboratory conditions. Here, the applicability of the McGrath method in translating the calcium carbonate-based mineralization achieved in 2D films onto 3D printed chitosan hydrogel-based scaffolds is investigated. Thereby, enabling the fabrication of 3D chitosan-calcium carbonate composites with properties sought in the context of prospective load-bearing bone grafts. In this work, considering the importance of interconnected porosity in an in vivo environment, nozzle extrusion-based 3D printing was employed to develop 3D structures with interconnected macropores, essentially imitating the porous structure of bone. The applicability of chitosan hydrogels as the printing ink in a custom-designed 3D printer was evaluated and quantified through rheological studies. The printing parameters and an appropriate experimental protocol were devised to fabricate stable 3D chitosan hydrogel-based scaffolds featuring physically crosslinked-layered structure with interconnected macropores. The effect of various drying techniques on retaining this porous structure in dried scaffolds and their swelling behaviour when soaked in a physiologically relevant solvent were explored using various techniques including cryo-scanning electron microscopy. The strategies required to mineralize the as-fabricated 3D chitosan hydrogel-based scaffolds via the McGrath method, such that the mineralization achieved within the 3D scaffolds is similar to that obtained within 2D films, were elucidated. This included the use of polyacrylic acid (PAA), a crystal growth modifier. PAA has previously been shown to be important in achieving a pancake-like calcium carbonate formation, comprised of laterally growing nanoparticle aggregates which form in association with the organic matrix, in 2D films; such structures are observed in the early stages of nacre formation. By modulating the period of exposure of the 3D scaffolds to the mineralization solutions and the concentrations of these solutions, it was found that 3D composites with up to 40% calcium carbonate content and varying crystal morphology could be fabricated using this mineralization method. Importantly, it was observed that the calcium carbonate crystallites were intricately associated with the organic hydrogel matrix. This is another essential element observed in biomineral systems. Various techniques such as scanning electron microscopy (SEM), thermogravimetric analysis (TGA), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) were employed for structural and compositional characterisation of the final composites. The prospect of fabricating 3D chitosan-calcium carbonate composites via a single-step method using chitosan hydrogel preloaded with calcium carbonate crystallites as the printing ink in our custom-designed 3D printer was also investigated. This method was studied as a faster and less labour-intensive alternative to developing composites via the two-step method devised in this research whereby 3D hydrogel-based scaffolds are printed first and then mineralized via the McGrath method. The advantages and disadvantages of the two fabrication techniques are compared. The two-step fabrication method was found to be superior in terms of the properties explored and desired in the composite. The behaviour of the chitosan hydrogel-based scaffolds and composites fabricated using the McGrath method, under different stress and strain regimes were also investigated. Mechanical tests performed on air-dried chitosan hydrogel-based scaffolds and composites showed that the compressive modulus, strength and indentation hardness values obtained were within the same order of magnitude as that of trabecular bone. Data from uniaxial compression tests showed that the yield, ultimate strength and compressive modulus of the 3D scaffolds vary with the total mineral content, morphology and size of the resultant crystallites in the composite. Composites with very low mineral content (~7% CaCO₃ content) showed the best mechanical properties under uniaxial compressive stress (approximately 0.37 GPa compressive modulus, 26 MPa yield strength, and 31 MPa ultimate strength). Nanoindentation tests showed that the nanoscale hardness and indentation modulus increased upon mineralization of the scaffolds but did not vary significantly as a function of the extent of mineralization. Dynamic mechanical analysis showed that the scaffolds (both mineralized and non-mineralized) can effectively dissipate stress without complete fracture when subjected to dynamic compressions within physiologically relevant loading frequencies (1 - 15 Hz) irrespective of the mineral content. The individual responses vary with loading frequency. Having ascertained the structural and mechanical attributes of the fabricated materials, their capacity to enable osteoblast cell attachment and proliferation was explored. Alamar Blue assay and confocal microscopy performed at various time points for samples exposed to in vitro cultured osteoblasts showed that chitosan hydrogel-based scaffolds and composites are biologically non-toxic and facilitate cell adhesion and proliferation. Furthermore, when osteoblasts were incubated with composites with low CaCO₃ content, the number of cells increased significantly within 14 days. The results of this research confirm that 3D printed chitosan hydrogel-based composites fabricated using the McGrath mineralization method featuring various structural and compositional imitations of bone and nacre shows considerable potential as future bone grafts materials.</p>

Eco-friendly packaging design made from teak leaf as the outer packaging layer for brownies

This study aimed to seeks a packaging design concept using environmentally friendly material. There are lots of dried teak leaves that pollute the yard. Without proper management, these leaves become garbage or rot and pollute the environment. This research applied qualitative descriptive method which is supported by quantitative analysis to determine the effectiveness of the environmentally friendly packaging design and market interest strategy for brownies. The creative design of environmentally friendly packaging from teak leaves was created to cover plain cardboard. The goal is to avoid the use of chemicals, namely kerosene, thinner, or printing ink. Instead of printing the cardboard, it is coated with dried teak leaves. This practice is environmentally friendly has aesthetic values. It is expected to attract potential consumers who care for the environmental preservation.

Binder Jet 3D Printing of Compound LEV-PN Dispersible Tablets: An Innovative Approach for Fabricating Drug Systems with Multicompartmental Structures

Three-dimensional (3D) printing is an emerging technology that has high application potential for individualized medicines and complex solid dosage forms. This study is designed to explore binder jet 3D printing (BJ-3DP) for the development of high-precision and repeatable compound levetiracetam-pyridoxine hydrochloride (LEV-PN) multicompartmental structure dispersible tablets. PN was dissolved in printing ink directly and accurately jetted into the middle, nested layer of the tablet, and precise control of the drug dose was achieved through the design of printing layers. With modification of the drying method, the “coffee ring” effect caused by drug migration during the curing and molding of the tablets was overcome. Furthermore, 3D topography showed that the tablets have a promising surface morphology. Scanning electron microscopy and porosity results indicated that the tablets have a loose interior and tight exterior, which would ensure good mechanical properties while enabling the tablet to disintegrate quickly in the mouth and achieve rapid release of the two drugs. This study used BJ-3DP technology to prepare personalized multicompartmental structures of drug systems and provides a basis for the development of complex preparations.