Scientific publications

We report the successful synthesis of nanocomposites between the MXene Ti3C2Tx and polyaniline (PAni), achieved via an innovative approach starting from the intercalation of anilinium ions into non-exfoliated Ti3C2Tx, and followed by a liquid/liquid interfacial polymerization. This approach produces transparent films with beneficial optical quality. The spectroscopic analysis confirmed the formation of PAni in its conductive form, emeraldine salt. The absence of TiO2 bands in the Raman spectra indicated that the organic polymer protected Ti3C2Tx from degradation, even in acidic media. Electrochemical characterization revealed that the nanocomposites exhibited promising performance as supercapacitors, with specific capacity dependent on the amount of polymer. The combination of the conductive Ti3C2Tx and the redox activity of PAni, as well as the specific nanoarchitecture in which the materials are organized, significantly improved the electrochemical response, facilitating ion diffusion. These transparent films demonstrated specific capacity values up to 89 mAh g-1 at 0.1 mAh g-1, with the potential for further enhancement through current collector optimization, positioning them as strong candidates for miniaturized energy storage applications and transparent devices.

Carbon allotropes are crucial to advanced interfaces to control friction and wear because of their unique range of mechanical properties: from diamond's hardness to graphite's lubricity. Friction force microscopy (FFM) is reported for diamond tips sliding on SiC(0001)-supported epitaxial graphene. A sharp friction increase is observed at a threshold normal force, linked to an intermittent graphene rehybridization. Comparing the FFM response of a diamond tip to that of a previously studied silicon tip with a comparable radius reveals a similar abrupt friction increase, though at roughly half the threshold force. Atomistic simulations of SiC(0001)-supported graphene sliding against hydroxylated amorphous carbon (a-C) and silicon oxide show low shear stress at low pressures for both systems. The shear stress increases at higher pressures due to bond formation between graphene and the counterbody. For a-C, the transition threshold shifts to higher pressures, consistent with FFM results. In simulations with high normal pressures, epitaxial graphene undergoes a structural transformation into single-layer diamond, contributing to the abrupt increase in friction. The graphene structure recovers after lifting the a-C counterbody, demonstrating structural robustness under tribological stress. These findings provide insights into the stability of low-friction interfaces between epitaxial graphene and key materials for current micro-electro-mechanical systems (MEMS)

Friction between fingertip and surface is a key contribution to tactile perception during active exploration of materials. We explore the role of skin factors such as stratum corneum thickness and hydration, deformability, elasticity, or density of sweat glands and of Meissner corpuscles in friction and tactile perception. The skin parameters were determined non-invasively for the glabrous skin at the index finger pad of 60 participants. Sets of randomly rough plastic surfaces and of micro-structured fibrillar rubber surfaces were explored as model materials with well-defined parameterized textures. Friction varies greatly between participants, and this variation can be explained to 70% by skin factors for the randomly rough plastic surfaces. The predictability of friction by skin factors is much lower for micro-structured rubber surfaces with bendable fibrils, where 50% of variance is explained for the stiffest fibrils but only 20% for the most bendable fibrils. The participants’ age is the key predictor for their tactile sensitivity to perceive the fibrils, where age is negatively correlated to the density of Meissner corpuscles. The results suggest that stratum corneum hydration, skin deformability, and age are important factors for friction and perception in active tactile exploration of materials.

Silver microflakes and -spheres are common fillers for electrically conductive screen-printing pastes. Here, we report on the effects of filler shapes and sizes on conductivity, sintering, and recyclability. We printed pastes based on flakes and spheres, treated them at 110 °C to 300 °C, and evaluated the electrical conductivity of the resulting layers. The electrical conductivity of the layers treated at 110 °C was dominated by particle–particle contact resistances; flakes yielded layers that were five times more conductive than sphere-based layers due to differences in the particle–particle contact area. Increasing temperature led to a reduction of the resistivity of all layers through sintering. At 300 °C, prints based on spheres were 4 times more conductive than those from flakes. Tomography of the sintered structures showed that the difference was caused by a lower tortuosity factor for spheres. In a final study, we showed that silver flakes and spheres could be recycled after sintering and reused for a new generation of prints without losing electrical performance. The more porous structure of sintered flakes allowed for higher recycling yields compared to spheres. At 140 °C, 91.6% of the flakes and 69.7% of the spheres were recovered as reusable dispersions.

Bispecific T cell engagers (TcEs) link T cell receptors to tumor-associated antigens on cancer cells, forming cytotoxic immunological synapses (IS). Close membrane-to-membrane contact (≤13 nm) has been proposed as a key mechanism of TcE function. To investigate this and identify potential additional mechanisms, we compared four immunoglobulin G1-based (IgG1) TcE Formats (A–D) targeting CD3ε and Her2, designed to create varying intermembrane distances (A < B < C < D). Small-angle X-ray scattering (SAXS) and modeling of the conformational states of isolated TcEs and TcE–antigen complexes predicted close contacts (≤13 nm) for Formats A and B and far contacts (≥18 nm) for Formats C and D. In supported lipid bilayer (SLB) model interfaces, Formats A and B recruited, whereas Formats C and D repelled, CD2–CD58 interactions. Formats A and B also excluded bulky Quantum dots more effectively. SAXS also revealed that TcE–antigen complexes formed by Formats A and C were less flexible than complexes formed by Formats B and D. Functional data with Her2-expressing tumor cells showed cytotoxicity, surface marker expression, and cytokine release following the order A > B = C > D. In a minimal system for IS formation on SLBs, TcE performance followed the trend A = B = C > D. Addition of close contact requiring CD58 costimulation revealed phospholipase C-γ activation matching cytotoxicity with A > B = C > D. Our findings suggest that when adhesion is equivalent, TcE potency is determined by two parameters: contact distance and flexibility. Both the close/far-contact formation axis and the low/ high flexibility axis significantly impact TcE potency, explaining the similar potency of Format B (close contact/high flexibility) and C (far contact/low flexibility). Copyright © 2025 the Author(s).

The development is proposed of a specific non-enzymatic amperometric sensor based on electrodeposited copper nanoparticles (Cu-NPs) for the determination of uric acid (UA) in fermentation samples. Through optimization of the Cu-NPs-containing sensing layer, it was demonstrated that copper(II)-induced oxidation (catalytic effect) in the presence of molecular oxygen is more effective for determining UA than the adsorption of UA on Cu and Cu-oxide surfaces. More importantly, simply changing the sensing layer’s surface chemistry by increasing the defect CuxOy on the surface of Cu-NPs after heating at 70 °C for only 20 min significantly improved the specificity of UA determination in both model and real fermentation samples (viz. supernatants of S. cerevisiae and E. coli). This study can be used as a guideline for the future assembly of functional electrodeposited sensing layers for the specific determination of target electroactive bioanalyte(s).

The synthesis of an amphiphilic three-arm block copolymer (AB)3-BCP, which consists of poly(methyl methacrylate) (PMMA) and poly(butyl methacrylate) (PBMA) in the hydrophobic inner block, is reported. The hydrophilic block segment is based on poly(2-hydroxyethyl methacrylate) (PHEMA) originating from 2-(trimethylsiloxyl)ethyl methacrylate (HEMA-TMS). The preparation is carried out in two steps using a core-first approach. Using atom transfer radical polymerization (ATRP) as a controlled polymerization technique, three (AB)3-BPCs with HEMA contents of 15 to 38 mol−1 % are prepared, applying different reaction conditions. Porous structures are generated from these BCPs by applying a self-assembly and nonsolvent-induced phase separation (SNIPS) protocol. Complex surface structures are observed using scanning electron microscopy (SEM). Bulk morphologies are investigated for a better understanding of the underlying self-assembly. For PHEMA-rich (AB)3-BCPs, non-regular lamellar microphases are observed in transmission electron microscopy (TEM) and confirmed by small-angle X-ray scattering (SAXS). The porous structures and their expected swelling characteristics are analyzed using atomic force microscopy (AFM) in air and water. Time-resolved measurements in water indicate a rapid swelling after immersion into the water bath. The present study paves the way for exciting porous materials based on the herein synthesized amphiphilic three-arm block copolymers useful for applications as absorber materials and coatings.

Tissue functions rely on complex structural, biochemical, and biomechanical cues that guide cellular behavior and organization. Synthetic cells, a promising new class of biomaterials, hold significant potential for mimicking these tissue properties using simplified, nonliving building blocks. Advanced synthetic cell models have already shown utility in biotechnology and immunology, including applications in cancer targeting and antigen presentation. Recent bottom-up approaches have also enabled synthetic cells to assemble into 3D structures with controlled intercellular interactions, creating tissue-like architectures. Despite these advancements, challenges remain in replicating multicellular behaviors and dynamic mechanical environments. Here, we review recent advancements in synthetic cell-based tissue formation and introduce a three-pillar framework to streamline the development of synthetic tissues. This approach, focusing on synthetic extracellular matrix integration, synthetic cell self-organization, and adaptive biomechanics, could enable scalable synthetic tissues engineering for regenerative medicine and drug development.

Lanthanide-doped upconversion microparticles (UCMP) enable composites for luminescence thermometry with long luminescence lifetime and narrowband absorption and emission spectra. Being non-toxic, easily synthesizable, and having a bright, stable emission makes them an attractive candidate for in-vivo monitoring of key environmental parameters such as temperature. We use them to create soft, biodegradable, miniaturized seed-like robots endowed with fluorescence tags for the sustainable environmental monitoring of topsoil and air above soil environments. Our aim is an airborne platform with a sufficient signal-to-noise ratio to identify the concentration of targeted soil parameters. Here, we study the photoluminescence of Er, Yb: NaYF4 UCMPs embedded in polylactic acid (PLA) polymeric matrix to assess their suitability for remote read-out. We assessed the signal-to-noise ratio in terms of excitation intensity, UCMP concentration, working distance, and sample orientation. We evaluated the signal stability over long exposure time as well as for amplitude-modulated excitation. Finally, we carried out ratiometric and lifetime measurements of luminescence emission in order to demonstrate the feasibility of such sensors in measuring the variation of temperature. Overall, the rare-earth doped UCMPs embedded in biodegradable polymer can be used for remote thermometry, displaying a significant signal-to-noise ratio for luminescence emission detection and subsequent derivation of temperature.

Long-lasting polypore fungi are significant producers of terpene cyclases of high interest for medicinal or biotechnological applications. Following the 1000 Fungal Genomes initiative launched by the Joint Genome Institute, the genome of Cubamyces (C.) menziesii and identified 18 genes encoding sesquiterpene cyclases (STCs) is explored. In a search for robust catalysts suitable for practical applications, the 18 codon-optimized open reading frames are cloned and overproduced the C. menziesii STCs in Escherichia coli. In ten cases, the catalytically active enzyme is purified and tested with three chemically synthesized linear diphosphates: geranyl diphosphate, farnesyl diphosphate (FDP), and geranylgeranyl diphosphate. Only FDP proved to be a substrate for these 10 enzymes. The product specificity of all these enzymes is determined by (GC-MS) gas chromatography mass spectrometry and (NMR) nuclear magnetic resonance analysis. Among the 10 enzymes, four produced a predominant compound, four yielded two main compounds, and the remaining two acted as a multiproduct catalysts. This work sheds light on the potential sesquiterpenes involved in the chemical ecology of the polypore C. menziesii and provides evidence for the potential of Polyporales fungi in the identification of new sesquiterpene cyclase activities.