cRGD-Peptide Modified Covalent Organic Frameworks for Precision Chemotherapy in Triple-Negative Breast Cancer

This study presents the use of nanoscale covalent organic frameworks (nCOFs) conjugated with tumor-targeting peptides for the targeted therapy of triple-negative breast cancer (TNBC). While peptides have previously been used for targeted delivery, their conjugation with COFs represents an innovative approach in this field. In particular, we have developed alkyne-functionalized nCOFs chemically modified with cyclic RGD peptides (Alkyn-nCOF-cRGD). This configuration is designed to specifically target αvβ3 integrins that are overexpressed in TNBC cells. These nCOFs exhibit excellent biocompatibility and are engineered to selectively disintegrate under acidic conditions, allowing for precise and localized drug release in tumor environment. Doxorubicin, a chemotherapeutic agent, has been encapsulated in these nCOFs with high loading efficiency. The therapeutic potential of Alkyn-nCOF-cRGD has been demonstrated in vitro and in vivo models. It shows significantly improved drug uptake and targeted cell death in TNBC, highlighting the efficacy of receptor-mediated endocytosis and pH-controlled drug release. This strategy leverages the unique properties of nCOFs with targeted drug delivery to achieve significant advances in personalized cancer therapy and set a new standard for precision chemotherapeutic delivery.

A 1,8-Naphthalimide-based Tripodal Fluorescent Chemosensor to Selectively Detect Copper Ions

A 1,8-naphthalimide-based tripodal fluorescent ligand (L3) was synthesized through the copper (I) catalyzed Huisgen azide-alkyne cycloaddition reaction of 2-(2-azidoethyl)-6-morpholino-1 H-benzo[de]isoquinoline-1,3(2 H)-dione with triproparagylamine. Naphthalimide acts as the fluorophore while the triazole and amine nitrogens chelate the metal ion. L3 showed a selective fluorescence turn-off for Cu(II) over other metal ions in aqueous acetonitrile solution. A Job's plot, Benesi-Hildbrand plot and high-resolution mass spectrometry data confirm a 1:1 binding stoichiometry with a binding constant of 7.8 х105 M- 1 while addition of disodium EDTA demonstrates its reversibility. The structure and stability of the complex was supported by theoretical calculations. The limit of detection for Cu(II) was calculated to be 0.3 µM which is considerably lower than WHO recommended Cu(II) limit in drinking water.

Interface Engineering of "Clickable" Organic Electrochemical Transistors toward Biosensing Devices

"Clickable" organic electrochemical transistors (OECTs) allow the reliable and straightforward functionalization of electronic devices through the well-known click chemistry toolbox. In this work, we study various aspects of the click chemistry-based interface engineering of "clickable" OECTs. First, different channel architectures are investigated, showing that PEDOT-N₃ films can properly work as a channel of the transistors. Furthermore, the Cu(I)-catalyzed click reaction of ethynyl-ferrocene is studied under different reaction conditions, endowing the spatial control of the functionalization. The strain-promoted and catalyst-free cycloaddition of a dibenzocyclooctyne-derivatized poly-l-lysine (PLL-DBCO) is also performed on the OECTs and validated by a fiber optic (FO)-SPR setup. The further immobilization of an azido-modified HD22 aptamer yields OECT-based biosensors that are employed for the recognition of thrombin. Finally, their performance is evaluated against previously reported architectures, showing higher density of the immobilized HD22 aptamer, and originating similar K_D values and higher maximum signal change upon analyte recognition.

Maximizing Conversion of Surface Click Reactions for Versatile Molecular Modification on Metal Oxide Nanowires

Click reactions (e.g., Huisgen cycloaddition) on metal oxide nanostructures offer a versatile and robust surface molecular modification for various applications because they form strong covalent bonds in a wide range of molecular substrates. This study reports a rational strategy to maximize the conversion rate of surface click reactions on single-crystalline ZnO nanowires by monitoring the reaction progress. p-Polarized multiple-angle incidence resolution spectrometry (pMAIRS) and Fourier-transformed infrared (FT-IR) spectroscopy were employed to monitor the reaction progress of an azide-terminated self-assembled monolayer (SAM) on single-crystalline ZnO nanowires. Although various reaction parameters including the concentration of Cu(I) catalysts, triazolyl ligands, solvents, and target alkynes were systematically examined for the surface click reactions, 10-30% of terminal azide on the nanowire surface remained unreacted. Temperature-dependent FT-IR measurements revealed that such unreacted residual azides deteriorate the thermal stability of the nanowire molecular layer. To overcome this observed conversion limitation of click reactions on nanostructure surfaces, we considered the steric hindrance around the closely packed SAM reaction points, then experimented with dispersing the azide moiety into a methyl-terminated SAM. The mixed-SAM method significantly improved the azide conversion rate to almost 100%. This reaction method enables the construction of spatially patterned molecular surface modifications on metal oxide nanowire arrays without detrimental unreacted azide groups.

Strategy to synthesise nano-engineered polymer nanocomposite with a mechanically strong interface: a highly flexible ammonia gas sensor

The work reported herein describes a facile strategy for synthesize of a highly flexible and free standing novel polymethyl methacrylate/nanographite platelets nanocomposite (P-NC) film through click chemistry.

A biosynthetic model of cytochrome c oxidase as an electrocatalyst for oxygen reduction

Creating an artificial functional mimic of the mitochondrial enzyme cytochrome c oxidase (CcO) has been a long-term goal of the scientific community as such a mimic will not only add to our fundamental understanding of how CcO works but may also pave the way for efficient electrocatalysts for oxygen reduction in hydrogen/oxygen fuel cells. Here we develop an electrocatalyst for reducing oxygen to water under ambient conditions. We use site-directed mutants of myoglobin, where both the distal Cu and the redox-active tyrosine residue present in CcO are modelled. In situ Raman spectroscopy shows that this catalyst features very fast electron transfer rates, facile oxygen binding and O-O bond lysis. An electron transfer shunt from the electrode circumvents the slow dissociation of a ferric hydroxide species, which slows down native CcO (bovine 500 s(-1)), allowing electrocatalytic oxygen reduction rates of 5,000 s(-1) for these biosynthetic models.