Appl. Nano, Volume 6, Issue 2 (June 2025) – 5 articles

Placing printed conductive patterns onto nonplanar substrates is a challenging task. In this work, we tested a simple method for depositing inkjet-printed conductive patterns onto 3D-printed pieces with cavities and sharp edges. First, a silver nanoparticle ink was used to print conductive patterns onto a flexible and porous substrate made of electrospun polycaprolactone (PCL). Then, the printed patterns were transferred to 3D-printed pieces made of polylactic acid (PLA) by temperature-promoted adhesion. Finally, the printed patterns were cured to render them conductive. The influence of the number of printed layers on their electrical and mechanical properties was evaluated. The printed patterns were also transferred to flexible substrates, such as thermoplastic polyurethane (TPU) and polyethylene terephthalate (PET) sheets, achieving conductivity after curing. Moreover, the printed patterns were effective for modular interconnection among successive transferred patterns, since it was possible to achieve electrical contact between them during the transfer process. Full article

Protein-bound nano-injectable solutions represent a cutting-edge advancement in nanomedicine, offering a versatile platform for precise and controlled drug delivery. By leveraging the biocompatibility and functional versatility of proteins such as albumin, gelatin, and casein, these nano systems enhance drug solubility, prolong circulation time, and improve site-specific targeting, which are particularly beneficial in cancer and inflammatory diseases. This review provides a comprehensive overview of their formulation strategies, physicochemical characteristics, and biological behavior. Emphasis is placed on therapeutic applications, regulatory considerations, fabrication techniques, and the underlying mechanisms of drug–protein interactions. This review also highlights improved pharmacokinetics and reduced systemic toxicity, while also critically addressing challenges like immunogenicity, protein instability, and production scalability. Recent FDA-approved formulations and emerging innovations in precision medicine and theranostics underscore the transformative potential of protein-based nanosuspensions in next-generation drug delivery systems. Full article

The synthesis of calcium carbonate (CaCO₃) nanoparticles has gained an increasing interest due to their improved properties and diverse industrial applications. Among various synthesis techniques, the mechanochemical synthesis process has emerged as a promising route for nano-CaCO₃ synthesis. A high-energy ball mill is required for synthesizing nano-CaCO₃, whereas post-milling heat treatment facilitates completing the reaction that remains incomplete during milling. Post-milling heat treatment may also influence the properties of synthesized CaCO₃, which has not yet been thoroughly investigated. This study investigated the influence of post-milling heat treatment on the polymorphs, micromorphology, and particle size distribution of CaCO₃. The results indicated that the heat treatment of the as-milled powder enhanced the homogeneity of crystal polymorphs while maintaining the particle sizes within the nano-range (<100 nm). X-ray diffraction (XRD) analysis identified two polymorphs (vaterite and calcite) in samples obtained from different milling intensities. However, after heat treatment, all vaterite transformed into calcite. A bimodal particle size distribution was observed in CaCO₃ nanoparticles and was influenced by both the milling and heating intensities. It was observed that 60 min heat applied to 30 min as-milled powder was enough to produce nano-CaCO₃ (<50 nm) where the percentage of larger particles (<250 nm) became negligible (~1%). Micromorphology images confirmed the transformation of crystal polymorphs and the reduction in particle size. Full article

Nanostructured hybrid materials based on the combination of semiconductor QDs and GO are promising candidates for different optoelectronic and catalytic applications and being able to produce such hybrid materials in solution will expand their possible range of applications. In the current work, capping ligand-exchange procedures have been developed to replace the lead oleate normally found on the surface of PbS QDs synthesized by the popular hot-injection method. After the capping ligand-exchange process, the QDs are water soluble, which makes them soluble in most GO solutions. Solution-processed nanostructured hybrid materials based on GO flakes decorated with ligand-exchanged (EDT, TBAI and L-Cysteine) PbS QDs were synthesized by combining PbS QDs and GO solutions. Afterward, the resulting hybrid materials were thoroughly characterized by means of FTIR, XPS, Raman, UV-Vis-NIR and photoluminescence spectroscopy, as well as SEM and TEM techniques. The results indicate a clear surface chemistry variation in the capping ligand-exchanged PbS QDs, showing the presence of the exchanged ligand molecules. Thin films from the solution-processed nanostructured hybrid materials were deposited by the spin coating technique, and their optoelectronic properties were studied. Depending on the capping ligand molecule, the photoresponse and resistance of the thin films varied; the sample with the EDT ligand exchange showed the highest photoresponse and the lowest resistance. This surface chemistry had a direct effect on the charge carrier transfer and transport behavior of the nanostructured hybrid materials synthesized. These results show a novel and accessible route for synthesizing solution-processed and affordable nanostructured hybrid materials based on semiconductor QDs and GO. Additionally, the importance of the surface chemistry displayed by the PbS QDs and GO was clearly seen in determining the final optoelectronic properties displayed by their hybrid materials. Full article

Rice is a staple food for nearly half the world population. Rice cultivation relies heavily on urea fertilization. However, the use of urea is prone to significant losses and contributes to environmental pollution. This study was aimed at fabricating nitrogen-rich chitin nanomaterials and assessing their effects on the growth and yield of rice. Chitin nanofibers (ChNF), with widths ranging from 10 to 30 nm, were successfully isolated from shrimp shells by chemical pretreatment and mechanical fibrillation. Pot-grown rice plants were treated with various concentrations of ChNF and urea in a completely randomized design with five replicates. ChNF treatment resulted in plant height (97.33 ± 1.53 cm), tiller number (17.67 ± 1.15 hill⁻¹), straw yield (30.40 ± 1.93 g hill⁻¹), and harvest indexes comparable to those achieved with urea treatment at harvest (97.33 ± 1.53 cm, 17.00 ± 1.73 hill⁻¹, 26.47 ± 2.39 g hill⁻¹ and 44.12%, respectively). The grain yield using urea (22.70 g hill⁻¹) was almost identical to that achieved with 0.01% ChNF (22.22 g hill⁻¹), which may be attributable to the increased nitrate-nitrogen (N) and ammonium-N availability, reduced nitrogen loss, and enhanced microbial activity associated with 0.01% ChNF. The study findings indicate that shrimp-derived ChNF is a promising functional nanomaterial for rice cultivation, with potential as a partial or full replacement for urea in sustainable rice production. Full article