Scientific publications

Cobaltocenium-containing polymers, an emerging class of materials, have historically been challenging to prepare due to their chemical robustness. In this work, we introduce a novel and highly efficient method for their preparation based on methacrylate-containing block copolymers (BCPs), allowing segment-selective introduction of functional moieties. The catalyst-free and quantitative hydroamination reaction we introduce has proven successful for the post-modification of amine-containing polymers with cobaltocenium. To demonstrate the versatility of this method, we successfully synthesized a series of BCPs consisting of polystyrene and a 5 to 20 wt% poly(tert-butyl aminoethyl methacrylate) (PtBAEMA) segment by living anionic polymerization. The selective functionalization with ethynyl-cobaltocenium hexafluorophosphate results in adjustable 5 to 40 wt% cobaltocenium units in the polymer as part of the PtBAEMA block segment. The success was monitored by IR spectroscopy, and the quantitative incorporation of the cobaltocenium moiety was verified by 1H NMR, UV-Vis spectroscopy, and TGA. DSC proved the block-selective cobaltocenium introduction by an additional glass transition temperature at 154 °C, and the strong microphase separation character of the amphiphilic BCPs leads to lamellar structures in the bulk state, as proven by TEM investigations. Finally, the water contact angle on polymer films is compared, showing polarity inversion and tunability upon conversion of hydrophilic amine to hydrophobic cobaltocenium hexafluorophosphate moieties. This successful synthesis and characterization of cobaltocenium-containing BCPs not only paves the way for a new class of metallopolymers but also offers functionalization possibilities for a variety of other responsive moieties, providing access to functional BCPs.

Histone deacetylases (HDACs) are enzymes that play crucial roles in cellular processes by hydrolyzing acetyl-L-lysine side chains in core histones, thereby regulating gene expression and maintaining homeostasis. Histone deacetylase inhibitors (HDACi) have emerged as promising agents, particularly in cancer treatment, due to their ability to induce cytotoxic and pro-apoptotic effects. Selective HDAC6 inhibitors, such as ITF3756, have shown low off-target toxicity and promising pharmacological activities, but their poor water solubility limits their application in nanoparticulate drug delivery systems. Here, we optimized a nanostructured lipid carrier (NLC) formulation for delivering ITF3756 using the design of experiments (DOE) and response surface methodology (RSM). An interaction between the factor surfactant and formulation volume was observed, thus demonstrating that the surfactant concentration impacts the NLC size. It can be speculated that the higher the amount of the drug in the formulation, the lower the polydispersion index (PDI), thus resulting in more stable nanostructures. The optimized ITF3756-NLC demonstrated a size of 51.1 ± 0.3 nm, 8.85 ± 4.71 mV charge, and high entrapment efficiency (EE%), maintaining stability for 60 days. Moreover, ITF3756-NLC enhanced α-tubulin acetylation in melanoma, lung, and brain cancer cell lines, indicating retained or improved bioactivity. The ITF3756-NLC formulation offers a viable approach for enhancing the bioavailability and therapeutic efficacy of HDAC6 inhibitors, demonstrating potential for clinical applications in cancer immunotherapy.

Carbon-based materials are cost-effective and eco-friendly but have limited sensitivity for detecting heavy metals. Density Functional Theory (DFT) is employed to design materials suitable for sensing, based on their interaction with analytes. Oxidized carbon black embedded with silver nanoparticles (OCB-Ag) is designed and studied via DFT, showing promising conductivity and arsenic interaction. Experimental validation confirmed its efficacy. The OCB-Ag nanocomposite was synthesized via in-situ preparation and used as an electrode material for arsenic detection. Characterization via UV–Visible spectroscopy and X-ray diffraction confirmed successful synthesis. Electrochemical interaction with arsenite was studied using square wave anodic stripping voltammetry. The OCB-Ag platform exhibited a linear current response up to 600 ppm of As3+, with a low limit of detection (0.01 ppm) and good sensitivity (5.9 µA ppm−1). The detection limit of electrode material for As3+ lies within the threshold value set by world health organization for drinking water. The experimental results validated the concept of designing electrochemical sensing platform through DFT, and its potential for detection of As3+.

Flexible and stretchable electronics require both sensing elements and stretching-insensitive electrical connections. Conductive polymer composites and liquid metals are highly deformable but change their conductivity upon elongation and/or contain rare metals. Solid conductive composites are limited in mechanoelectrical properties and are often combined with macroscopic Kirigami structures, but their use is limited by geometrical restraints. Here, we introduce “Electrofluids”, concentrated conductive particle suspensions with transient particle contacts that flow under shear that bridge the gap between classic solid composites and liquid metals. We show how Carbon Black (CB) forms large agglomerates when using incompatible solvents that reduce the electrical percolation threshold by 1 order of magnitude compared to more compatible solvents, where CB is well-dispersed. We analyze the correlation between stiffness and electrical conductivity to create a figure of merit of first electrofluids. Sealed elastomeric tubes containing different types of electrofluids were characterized under uniaxial tensile strain, and their electrical resistance was monitored. We found a dependency of the piezoresistivity with the solvent compatibility. Electrofluids enable the rational design of sustainable soft electronics components by simple solvent choice and can be used both as sensor and electrode materials, as we demonstrate.

The cobalt sulfide (CoS2) and nickel cobaltite (NiCo2O4) nanostructures are individually prepared and layered one over the other in reverse order to explore their effects on energy storage applications. The physicochemical characterization is conducted using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and transmission electron microscopy. The water contact angle of these nanostructures is also measured to assess their affinity toward aqueous electrolytes. The electrochemical performance and the contribution from surface-limited to diffusion-limited charge storage are measured. Among all the prepared nanostructures, cobalt sulfide grown over nickel cobaltite (CS/NCO) exhibited the highest specific capacity of 508.6 mAh⸳g−1 at a specific current of 1 A⸳g−1 using three electrode system. The same electrode demonstrated the highest specific power of 115.1 W⸳kg−1 in combination with a specific energy of 226.4 Wh⸳kg−1. Moreover, asymmetric device was also fabricated that exhibited maximum specific capacity of 49.8 mAh⸳g−1 at the specific current of 1 A⸳g−1, and specific energy of 93.0 Wh⸳kg−1 at specific power of 774.8 W⸳kg−1. The specific capacity of the full cell is retained up to 78.9 % after 5000 cycles. The post-electrochemical evaluation of CS/NCO is performed and the outcomes suggested that fabricated CS/NCO‖AC has promising future in the energy storage applications. Additionally, It is proposed that reversing the growth order of nanostructures in a hybrid electrode material is a potential pathway to optimize its electrochemical performance for energy storage applications.

Circumventing the limitations of current bioassays, we introduce a light-controlled assay, OptoAssay, toward wash- and pump-free point-of-care diagnostics. Extending the capabilities of standard bioassays with light-dependent and reversible interaction of optogenetic switches, OptoAssays enable a bidirectional movement of assay components, only by changing the wavelength of light. Demonstrating exceptional versatility, the OptoAssay showcases its efficacy on various substrates, delivering a dynamic bioassay format. The applicability of the OptoAssay is successfully demonstrated by the calibration of a competitive model assay, resulting in a superior limit of detection of 8 pg ml−1, which is beyond those of conventional ELISA tests. In the future, combined with smartphones, OptoAssays could obviate the need for external flow control systems such as pumps or valves and signal readout devices, enabling on-site analysis in resource-limited settings.

Skin equivalents (SE) that recapitulate biological and mechanical characteristics of the native tissue are promising platforms for assessing cosmetics and studying fundamental biological processes. Methods to achieve SEs with well-organized structure, and ideal biological and mechanical properties are limited. Here, the combination of melt electrowritten PCL scaffolds and cell-laden Matrigel to fabricate SE is described. The PCL scaffold provides ideal structural and mechanical properties, preventing deformation of the model. The model consists of a top layer for seeding keratinocytes to mimic the epidermis, and a bottom layer of Matrigel-based dermal compartment with fibroblasts. The compressive modulus and the biological properties after 3-day coculture indicate a close resemblance with the native skin. Using the SE, a testing system to study the damage caused by UVA irradiation and evaluate antioxidant efficacy is established. The effectiveness of Tea polyphenols (TPs) and L-ascorbic acid (Laa) is compared based on free radical generation. TPs are demonstrated to be more effective in downregulating free radical generation. Further, T1 relaxometry is used to detect the generation of free radicals at a single-cell level, which allows tracking of the same cell before and after UVA treatment.

Recent advances in engineered bacterial therapeutics underscore their potential in treating diseases via targeted, live interventions. Despite their promising performance in early clinical phases, no engineered therapeutic bacteria have yet received approval, primarily due to challenges in proving efficacy while ensuring biosafety. Material science innovations, particularly the encapsulation of bacteria within hydrogels, present a promising avenue to enhance bacterial survival, efficacy, and safety in therapeutic applications. This review discusses this interdisciplinary approach to develop living therapeutic materials. Hydrogels not only safeguard the bacteria from harsh physiological conditions but also enable controlled therapeutic release and prevent unintended bacterial dissemination. The strategic use of encapsulation materials could redefine the delivery and functionality of engineered bacterial therapeutics, facilitating their clinical translation.

Efficient separation of specific ions from aqueous media is crucial for advanced water treatment and resource recovery. Flow electrode capacitive deionization (FCDI) offers potential for selective ion removal through continuous operation. This study evaluates the performance of selective cation separation using a commercial activated carbon slurry in a multi-ion solution of monovalent (Li+, Na+, K+) and bivalent (Ca2+, Mg2+) cations. We assess ion removal and cation selectivity under different operational parameters, such as applied potential, slurry flow rate, and feed water flow rate. Our data show that bivalent cations, namely Ca2+ and Mg2+, are preferentially removal due to their higher charge-to-size ratio, aligning with hydrated ion sizes. The highest separation rate was observed for Ca2+ (5.7 μg cm−2 min−1), and the lowest for Li+ (0.2 μg cm−2 min−1). At the highest applied voltage (1.2 V), charge efficiencies reached 70 %, with an energy consumption of 41 Wh mol−1 for nearly complete cation removal. Optimal conditions were identified with a slurry flow rate of 6 mL min−1, feed water flow rate of 2 mL min−1, activated carbon content of 10 mass%, 1 mass% carbon black, and a cell voltage of 1.2 V. These findings highlight the importance of optimizing operational parameters to enhance ion removal.