The mechanism of the sol-gel synthesis, a key step in the preparation of silica aerogels (SA) from alkoxysilanes, is studied on example of a BF3-catalyzed process. "Stop-flow" NMR without MAS is chosen for in situ monitoring of the reaction. Using this procedure, the reaction mixture is maintained at r.t. for a specified time before being frozen to -80°C, at which point all chemical transformations cease, and subsequently studied via NMR. It allows continuous structure studying of both soluble low-molecular-weight intermediates and the successively formed nanoparticles (NPs) within the sol and solid materials (wet gel and SA) under unchanged conditions. 1D, 2D, and 3D 29Si NMR are used as main method to determine the structure of the Si-intermediates. An extended H-bonded network between both low-molecular- and high-molecular-weight Si-intermediates allows detecting even short-living and difficult-to-detect intermediates. The use of 1D and 2D 1H, 11B, 19F, and 29Si NMR experiments provides detailed information on the evolution of the BF3-precatalyst into B-containing Lewis acids and F-containing Brønsted bases as catalytic species. Their interactions with Si─OEt- and Si─OH-containing intermediates are studied. Using rheology, dynamic light scattering (DLS) and DLS in an electric field, the observations obtained by NMR were confirmed independently.

Preeclampsia is a leading cause of maternal and fetal morbidity, with altered placental function being a key contributor to its pathogenesis. Extracellular vesicles (EVs) derived from the placenta have emerged as promising biomarkers for early diagnosis of preeclampsia. However, current EV isolation techniques face challenges related to specificity, yield, and preservation of vesicle integrity. In this proof-of-concept study, we develop a work scheme for the selective isolation of placental EVs and the detection of messenger RNA (mRNA) biomarkers. The coordination polymer is formed using terbium ions and guanosine monophosphate, with the incorporation of monoclonal antibodies targeting placental alkaline phosphatase (PLAP), a marker of trophoblast-derived EVs. Our results show that antibody-functionalized terbium coordination polymer particles efficiently captured PLAP-positive EVs, which could be gently released, preserving their integrity for downstream analysis. Transmission electron microscopy confirms the recovery of intact EVs, while Quantitative Reverse Transcription Polymerase Chain Reaction analysis is performed for the detection of KISS1 mRNA, a potential biomarker for preeclampsia. This method offers a gentle, efficient, and specific approach for EV isolation, providing a valuable tool for studying placental dysfunction and advancing biomarker analysis in preeclampsia.

Two-photon polymerization (TPP) is a powerful technique to create microscale structures with high precision, offering significant potential in tissue engineering and drug delivery.While conventional TPP-fabricated drug carriers rely on passive encapsulation, these systems often suffer from low payload capacity and diffusion-controlled release kinetics. To address these challenges, we present the first demonstration of TPP-printed polyprodrug microstructures, where the therapeutic agent is covalently integrated into the polymer network as the repeating unit itself. Estrogen-based diacrylate monomers derived from 17β-estradiol were synthesized via one-step esterification/transesterification to create a photocurable resin. Curing under flood UV irradiation yielded a rigid thermoset (E' ∼2.5GPa at 25°C) with a glass transition temperature of about 50°C. Using TPP, we fabricated various microscale needles (100 × 100 × 400 µm, 2 µm resolution) from this resin, enabling direct printing of intrinsically therapeutic microstructures without post-processing drug loading. The cured polymer acts as both a structural matrix and a hydrolytically degradable polyprodrug, releasing estradiol through cleavage of ester bonds. By combining covalent drug-polymer integration with high-resolution 3D printing, this work establishes a platform for personalized transdermal drug delivery devices with spatially controlled release profiles determined by microstructure design and polymer degradation kinetics.

Sustainable production of polylactide demands catalysts that are both recoverable and capable of delivering precise molar mass and stereocontrol. A series of heterobimetallic complexes [(THF)NaFe(OtBu)3]2, [(THF)2KFe(OtBu)3]2, [KZn(OtBu)3]2, [(THF)KCu(OtBu)3]∞ and [(THF)KCo(OtBu)3]2 was evaluated as precursors for heterogeneous catalysts by grafting onto dehydroxylated silica. All complexes demonstrated activity in the ring-opening polymerization of lactide. Notably, the silica-supported [(THF)KFe(OtBu)2]/SiO2-700 and [(THF)NaFe(OtBu)2]/SiO2-700 systems exhibited high efficiency, promising recyclability, and afforded predictable molar masses (Mn,exp close to Mn,th) with narrow dispersities. These findings highlight new opportunities for designing recyclable catalysts for sustainable PLA synthesis.

Time-dependent dynamic afterglow carbon dots (TDDA-CDs) demonstrate considerable application potential in the fields of anti-counterfeiting, information encryption, and light-emitting diodes (LEDs), owing to their excellent optical properties, low toxicity, and favorable biocompatibility. In recent years, many reports have been published on the TDDA phenomenon of CDs, and significant progress has been made. However, systematic summaries of CDs with TDDA are rare. This review provides a comprehensive summary of recent developments in TDDA-CDs, with particular emphasis on synthetic strategies, including matrix-assisted synthesis and matrix-free direct synthesis from raw materials. Furthermore, various proposed emission mechanisms are discussed in detail, such as dual room-temperature phosphorescence (RTP) centers, hybrid RTP/thermally activated delayed fluorescence (TADF) systems, and phosphorescence Förster resonance energy transfer (FRET)-mediated delayed fluorescence (DF) processes. Finally, the practical applicability of TDDA-CDs in anti-counterfeiting, information encryption, and LEDs is critically evaluated. This review aims to guide the rational design and development of multifunctional TDDA-CDs for advanced applications in secure information systems and intelligent optoelectronic devices.

The spontaneous transformation in isotactic poly(butene) (iPB) of kinetically favored form II into the thermodynamically stable form I at room temperature leads to dimensional instability due to changes of density and strength and has prevented industrial development of iPB. This transformation is accelerated by tensile deformation. This study investigates the correlation between the form II-form I transition occurring during tensile deformation and orientation of relative crystallites in 1-butene/ethylene (C4C2) isotactic copolymers. During stretching, form II transforms into form I in all samples. Both the critical strain at which the form II-to-form I transition begins (εc) and the strain at which 50% of the initial form II is transformed into form I (ε0.5) increase with increasing ethylene (C2) content. For samples with C2 content ≤ 7.6 mol%, form II crystals adopt an off-axis orientation at ε0.5. In contrast, for higher C2 content, form II crystallites remain isotropic at ε0.5. Form I crystals adopt an off-axis orientation at ε0.5 only in the two samples with lowest C2 content (1.7 and 4.3 mol%). Crystals of form II and form I begin to orient in the standard fiber orientation at progressively earlier stages of the form II-to-form I transition as the ethylene content increases.

Polyesterurethanes are versatile polymers widely utilized in applications such as foams and adhesives, yet their industrial production relies on toxic and carcinogenic diisocyanates. To address this, isocyanate- and phosgene-free synthetic methods have been explored, with ring-opening polymerization of cyclic carbamates emerging as a promising alternative. This study presents the coordinative ring-opening copolymerization of limonene-based cyclic carbamates with ε-caprolactone to synthesize AB-block polyesterurethanes. Using the presented method, tunable block copolymer compositions were achieved, verified by NMR, GPC, and FT-IR analyses. Thermal and optical characterizations by DSC and UV-vis revealed an adjustable glass transition temperature between -9°C and -59°C and transmittance up to 84% for PLU-b-PCL (49:51), while tensile testing demonstrated customizable mechanical properties. Notably, PLU-b-PCL (5:95) exhibited an elongation at break of 582%. These findings provide a basis for sustainable polyesterurethane synthesis by ring-opening copolymerization and demonstrate the versatility of this method.

Pseudomonas aeruginosa forms biofilms that complicate treatment of infections, with lectins LecA and LecB playing crucial roles in this process. This study investigates the inhibitory effect of glycosylated nanogels on lectin binding and biofilm formation. Nanogels presenting melibiose (α-galactose) and fucose (β-fucose) effectively reduce LecA and LecB binding, respectively, in competitive inhibition assays against immobilized glycoproteins. Melibiose nanogels are more potent inhibitors than fucose nanogels, as α-galactose is more strongly bound by LecA than β-fucose by LecB. Both types of glycogels have a high impact on P. aeruginosa biofilm formation. Notably, the timing of glycogel application significantly influences biofilm dynamics; pre-treatment leads to a 75% reduction in biofilm formation, whereas treatment after biofilm initiation results in a 60% increase in biofilm growth, suggesting that these glycogels can act as both inhibitors and enhancers of biofilm development. The findings highlight the complexity of carbohydrate-based interactions in biofilm modulation and underscore the necessity for precise dosing and structural optimization in developing effective strategies against infections caused by biofilm-forming bacteria.

Deformation of glassy polymers induces plastic flow as a result of mechanical instability, ultimately leading to cavitation and fracture of the liquid. Thus, understanding the origin of such mechanical instability is crucial. Here, we demonstrate that strain deformation of polymeric glass is accompanied by marked shear-thinning behavior and leads to enhanced density fluctuations. These results are consistent with Furukawa and Tanaka's theory, which predicts that strain induces the self-amplification of the density fluctuations. Thus, we conclude that the enhancement results from the coupling between the velocity field and density fluctuations, stemming from the Furukawa and Tanaka theory, glassy polymer, small-angle X-ray scatteringstrong density dependence of viscosity.

The interfacial assembly and rearrangement of nanomaterials are critical for stabilizing air-water/oil-water interfaces. Cellulose nanofibers (CNFs) are promising renewable bio-based solid surfactants that form stable interfacial layers separating the fluid interface. However, the correlations between microstructural features (e.g., defects, orientation, buckling) and physicochemical properties of the interfacial layer remain unclear. This study attempted to understand the interfacial behaviors of CNFs with different hydrophobicity through a common mechanism. First, nanofiber monolayers were fabricated on the water surface of a Langmuir trough. Three different regions corresponding to gaseous, liquid expanded, and liquid condensed films were determined from the characteristic points of surface pressure isotherms. The film structures and their surface dilatational storage/loss moduli exhibited significant changes across these three regions. Overall, we propose that the interfacial behaviors of nanofiber monolayers can be organized by macroscopic wettability of nanofibers which is readily measurable. These results provide insights into the interfacial stabilization mechanism of fibrous nanomaterials and pave the way for applications in functional Pickering emulsions/foams.