Research Topics

Self-Assembly on Surfaces & surface functionalization

Utilizing self-assembly emerges as the most promising avenue for constructing organic nanostructures on surfaces, resulting in the creation of hybrid organic-inorganic materials. This strategy capitalizes on the thermodynamic control and reversibility of self-assembly to achieve the precise formation of 3D architectures, such as coordination cages, directly on surfaces. This precision is crucial for advancing nanotechnology and molecular electronics. By extending the self-assembly process to technologically relevant surfaces like silicon, we can craft hybrid inorganic-organic structures with selective inclusion and other valuable properties. The ability to generate intricate organic architectures on silicon holds immense significance for the development of integrated devices with distinctive optical, magnetic, and sensing characteristics.

Environmental Sensing

Ensuring fast, widespread, and reliable monitoring of carcinogenic compounds at minimal concentrations in the air is a critical goal for environmental and health organizations. The chemical community faces a significant challenge in benzene detection, requiring innovative, multidisciplinary solutions. The supramolecular approach to analytical sampling materials stands out as a noteworthy advancement, providing selectivity to analytical techniques and tailoring material adsorption selectivity for targeted analytes. This enables remarkable analytical outcomes. Molecular recognition, crucial for sensor performance, has seen popularity in chemical sensing due to advancements in mastering weak interactions. However, the gap between synthetic receptors and real-world sensor applications persists. This research aims to bridge this gap, focusing on the environmental monitoring of toxic aromatic VOCs. Selective monitoring of airborne aromatic VOCs, particularly BTEX (benzene, toluene, ethyl benzene, and xylenes), is both socially relevant and technologically challenging. Real-time air monitoring often relies on bulky laboratory equipment, and existing low-cost sensor systems lack sufficient selectivity for reliable quantification. Molecular receptors, such as tetraquinoxaline cavitands (QxCav), offer a promising solution. Our group has utilized QxCav molecules to fabricate low-cost systems with sub-ppbv detection limits for toxic VOCs, demonstrating selective trapping of aromatic vapors at the gas-solid interface. The rational design of QxCav molecular structures provides avenues for further improving sensitivity and selectivity. This research has led to the commercial device PyxisGC in collaboration with Pollution, where our cavitands serve as preconcentrators, showcasing practical applications of our findings in urban monitoring.

Advanced materials and supramolecular polymers

The design and preparation of supramolecular polymers represent a cutting-edge area in contemporary chemistry, holding significant potential for scientific breakthroughs and technological applications. These polymers are characterized by the reversibility of interactions among constituent monomers, granting them two crucial properties: responsiveness to external stimuli and self-healing capabilities, both highly sought-after in materials science. Our research has introduced a bimodal self-assembly protocol for creating a dual-coded supramolecular polymer. By combining solvophobic aggregation and metal-coordination, two orthogonal and reversible interactions, we achieve precise control over the self-assembly process, resulting in the formation of rod-like supramolecular architectures. Additionally, we've developed a new class of supramolecular polymers driven by the exceptional complexing properties of tetraphosphonate cavitands with methylpyridinium guests. These cavitand monomers, featuring host functionality at the upper rim and guest units at the lower rim, self-assemble to form homopolymers with remarkable supramolecular plasticity. Competitive guest-triggered reversibility and template-driven conversion from linear to star-branched polymers showcase the system's flexibility. The same host-guest association mode has been employed for copolymer formation, featuring intriguing temperature-driven cyclic to linear polymer interconversion.

Supramolecular Sensors

Chemical sensors are essential in daily life, used for environmental monitoring, industrial control, food quality assurance, and more. However, a common challenge is their tendency to produce false responses, often due to a lack of selectivity towards target molecules. Advances in supramolecular chemistry provide opportunities to design molecules with superior recognition properties for use in chemical sensors. In our recent review, we focus on designing synthetic molecular receptors for gas sensors, using cavitands as a case study. These organic compounds with molecular-sized cavities exemplify the necessary steps to create effective supramolecular sensors for organic vapors. Overcoming challenges, such as non-specific dispersion interactions, is crucial for achieving sensor selectivity. Reversibility of responses is essential, requiring the use of weak interactions to prevent irreversible saturation of the chemical layer. The design involves selecting appropriate weak interactions based on the analytes to be detected. Molecular recognition in the liquid phase does not directly apply to vapor and gas sensing, necessitating a careful receptor design and a comprehensive study of complexation phenomena. To minimize non-specific interactions, reducing the thickness of the receptor layer, especially with surface plasmon resonance (SPR) transducers, has proven effective. SPR, an optical phenomenon, provides a safe and selective means of sensing. Our review demonstrates the effectiveness of supramolecular SPR sensing using cavitands as receptors for volatile organic vapors and nerve gas simulants, highlighting its potential for selective chemical warfare agent detection.

Biochemical sensing

Over the past few decades the detection of biochemical markers has been mainly based on immunological techniques, because antibodies offer unrivalled specificity, particularly when the analytes are large molecules like proteins. Strictly speaking, immunoassays are dosimeters not sensors, since they lack reversibility. Therefore, they are not amenable for continuous monitoring. Moreover, they are often expensive, unstable, and cannot be prepared for some types of analytes. Typical problems encountered with antibodies are poor batch-to-batch reproducibility and reduced selectivity between similar analytes, like the misidentification of epitopes. In the cases where these drawbacks are crucial, alternative solutions must be considered. In this context, supramolecular chemistry offers a wide choice of synthetic receptors tuned for binding a large number of analytes, ranging from simple ions to complex organic molecules. Macrocycles like cyclodextrins, calixarenes, cucurbiturils and cavitands are the workhorses of synthetic receptors, featuring excellent molecular recognition properties for a large and diverse pool of guests. Our group uses tetraphosphonate cavitands for the selective to selectively complex biologically relevant markers via synergistic host-guest interactions. Our research demonstrated the ability of tetraphosphonate cavitands in selectively complexing sarcosine, a potential marker of prostate cancer in urine, via electrochemiluminescence as well as its capability and specificity in complexing mono-methylated lysines in water. This ability was successfully applied to the detection of the mono-methylation state of lysines present in human histone H3 tails

Articles

Patents

VIT Project

The VIT project, approved and funded by the European Commission under the last call of the Horizon 2020 MSCA-RISE, is coordinated by our research group. The international consortium, consisting of 10 academic research groups spanning three continents (Europe, America, Asia), along with two innovative companies (Bormioli Pharma and Portuguese Plux Wireless Biosignals), focuses on Polymer engineering via molecular design, specifically dealing with vitrimers. Vitrimers are novel polymers possessing thermoset-like mechanical properties at operating temperatures, yet they exhibit thermoplastic flow at elevated temperatures. This unique characteristic addresses challenges associated with the use of composites in structural applications, as traditional composites cannot be easily recycled due to their inability to flow at high temperatures. The VIT project aims to enhance vitrimers with optical and electrical properties, making them suitable for use in sustainable mobility, particularly in electric cars (E-cars). The goal is to ensure that these properties persist even after recycling, aligning with the principles of the circular economy, specifically the "use-reuse-repair-recycling" paradigm. The project involves the secondment of 97 PhD/postdoc students across Europe and globally to capitalize on the consortium's expertise in chemistry and functional materials processing. The overarching objective is to develop an advanced generation of vitrimers capable of meeting the requirements of both sustainable mobility and the circular economy. Additionally, the project seeks to foster the careers of young researchers and enhance international and intersectoral scientific collaborations.

ENRICH Project

Scientific studies indicate that inefficient epigenetic control is associated with a wide variety of non-communicable diseases (NCDs) like cancer, schizophrenia, and diabetes. Indeed, histone post translational modifications (PTMs) are crucial for many cellular processes including transcription and DNA repair. Thus, the ability to readily and reliably detect PTMs is crucial to better understand epigenetic processes and the complex functions of histone PTMs in human diseases. Mass spectrometry (MS) is the technique of choice to identify such modifications across the proteome. MS requires an enrichment step generally performed using antibodies, but these have several limitations such as high costs, batch-to-batch variability and data reproducibility. In a multidisciplinary effort ENRICH aims at developing new cost-effective, fast and efficient tools for the enrichment of post translationally modified proteins overcoming the current limitation. ENRICH will functionalize nanoparticles (NPs) with molecular receptors able to enrich PTMcontaining peptides, derived from proteolytic digestion, for subsequent MS analysis. Concurrently, the ability and selectivity of the synthesized receptors and functionalized NPs will be evaluated via spectroscopic analyses. The ENRICH network gathers the expertise required to tackle this challenge. The consortium is composed of 9 high-level academic research groups from 2 different continents (Europe and America) and 2 highly innovative companies. By the seconding of 87 ERs/ERSs across Europe and worldwide, the aim is to capitalize on the consortium expertise in complementary fields such as chemical synthesis, spectroscopy, and proteomics. The network promotes an effective integrate training of researchers, boosting their career development, and promotes collaborations between the partners. The direct involvement of industries guarantees the timely exploitation of the results from research laboratories to innovative products.