Chiral Fluorescent Uranyl-Salen Oligomer for Enantiomeric Supramolecular Recognition of Tryptophan Andrea Pappalardo, Angelo Nicosia, Aurore Fraix, Rossella Santonocito, Placido Mineo, et al. Current Organic Chemistry, 2026 introduction: The development of enantioselective fluorescent sensors is of great interest for the detection of biologically relevant molecules such as amino acids. Tryptophan (Trp), in particular, plays a critical role in biochemical processes, and its selective recognition remains a challenging task. In this study, we report the synthesis and characterization of a new chiral oligomer based on an oligo-(p‑phenyleneethynylene) backbone functionalized with multiple Lewis acidic metal centers—specifically uranyl ions. This system represents the first example of a uranyl-salen oligomer exhibiting strong fluorescence and high selectivity toward Trp. materials and methods: The chiral oligomer was synthesized via a stepwise coupling of p‑phenyleneethynylene units, followed by complexation with uranyl ions to introduce Lewis acidic centers. The resulting oligomer was characterized using NMR, UV-Vis, fluorescence spectroscopy, and mass spectrometry. Enantioselective binding studies were conducted by fluorescence titration using L- and D-tryptophan. The formation of supramolecular assemblies upon Trp recognition was investigated by dynamic light scattering (DLS) to assess changes in particle size. results: The resulting uranyl-functionalized oligomer displayed significant fluorescence, making it the first example of a fluorescent uranyl-oligomer of this kind. The sensor demonstrated a high affinity for L-tryptophan, with an enantiodiscrimination ratio exceeding 40:1 over the D-enantiomer. The limit of detection was found to be in the sub-ppm range. DLS analysis confirmed the formation of micrometer-sized aggregates upon interaction with Trp, indicating non-covalent host–guest interactions and supramolecular organization. discussion: The unique conjugated structure of the oligomer, combined with the Lewis acidity of uranyl centers, provides a synergistic effect for selective and sensitive detection of L-tryptophan. The significant enantioselectivity observed suggests a specific chiral environment within the oligomeric scaffold, which is not replicated for the D-isomer. The fluorescence response and aggregation behavior further support the role of Trp in driving the formation of higher-order structures through molecular recognition. conclusion: This study presents the first fluorescent uranyl-salen oligomer capable of selectively recognizing L-tryptophan with high sensitivity and enantioselectivity. The system offers new insights into the design of supramolecular sensors based on metal-organic oligomers and opens new avenues for the development of chiral sensing platforms targeting biologically important molecules.
Amphiphilic cyclodextrin-based nanocarriers for magnetic delivery of a morphogen in microfluidic environments Alessandro Surpi, Roberto Zagami, Marianna Barbalinardo, Nina Burduja, Giuseppe Nocito, et al. Materials Advances, 2025 A supramolecular assembly based on a cyclodextrin-based nanocarrier hosting superparamagnetic nanoparticles and retinoic acid can be magnetically guided through microfluidic environments to induce differentiation of SH-SY5Y cells therein cultured.
Covalently Functionalized Halloysite-Calixarene Nanotubes for Injectable Hydrogels: A Multicavity Platform for Hydrophobic Drug Delivery Giuseppe Cinà, Marina Massaro, Andrea Pappalardo, Carmela Bonaccorso, Cosimo G. Fortuna, et al. Pharmaceuticals, 2025 Background: Poor water solubility is a major limitation for the therapeutic use of many anticancer drugs. In this study, we report the design and development of two halloysite-based hybrid nanomaterials for the encapsulation and delivery of hydrophobic and positively charged drugs. Methods: A novel multicavity platform was obtained by covalently grafting calix[5]arene macrocycles onto the external surface of halloysite nanotubes (HNTs), combining lumen encapsulation with supramolecular host–guest recognition. PB4, a planar and hydrophobic pyridinium salt with significant antiproliferative activity, was selected as a model compound. Both PB4-loaded HNTs (HNTs/PB4) and calixarene-functionalized HNTs (HNTs-Calix/PB4) were incorporated into Laponite®-based thixotropic hydrogels to obtain injectable and biocompatible systems. Results: The nanomaterials were thoroughly characterized, and their loading efficiency, release behavior, and aqueous dispersibility were evaluated. Antiproliferative tests on MCF-7 cells demonstrated that both hydrogels retained PB4 activity, with distinct release profiles: the pristine HNTs allowed faster drug availability, while calix[5]arene-functionalized systems promoted sustained release. Conclusions: This work introduces the first example of covalently calixarene-functionalized halloysite and presents a versatile drug delivery platform adaptable to different therapeutic contexts and combination strategies.
