Technische Universität Darmstadt

Materials with magnetic anisotropy can serve as a model object for exploring the multicaloric effect because their thermodynamic state alterations can be achieved either through the application of a magnetic field H or/and by mechanically rotating the sample in the magnetic field using torque τ. In such materials, the total entropy change __-mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"-__Δ S T arises from two distinct contributions: (1) the conventional magnetocaloric effect (MCE) or paraprocess __-mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"-__Δ S m and (2) the rotational MCE __-mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"-__Δ S φ . In this manuscript, using molecular field model which enables a separation of contributions to the total entropy change __-mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"-__Δ S T from conventional __-mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"-__Δ S m and rotational __-mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"-__Δ S φ , we have determined cross-coupling multicaloric coefficients __-mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"-__ χ τ , H = ∂τ ∂H T , θ and __-mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"-__ χ H , τ = - ∂m ∂θ T , H for anisotropic magnetic materials and show that they satisfy the basic thermodynamic identities. We also confirmed that the total multicaloric effect in the material with magnetic anisotropy can be accurately expressed as the sum of the individual magnetocaloric effects induced by separate application of the H and τ, minus the magnetic entropy change arising from thermodynamic cross-coupling between the subsystems of the solid: __-mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"-__   Δ S T = Δ S T , τ H + Δ S T , H θ -   Δ S coupling .

The discovery and development of multispecific antibodies present unique challenges in optimizing their physicochemical properties to enhance developability and manufacturability. Common developability challenges include increased risk of aggregation, high viscosity, poor solubility, low expression yields, complex purification requirements, greater propensity for fragmentation, immunogenicity, or pharmacokinetics. In this study, we systematically investigate the solution behavior of engineered bispecific IgG1-VHH constructs derived from a parental NKp30 ×EGFR natural killer cell engager (NKCE) molecule, focusing on colloidal stability, hydrophobicity, thermal stability, pH sensitivity, and viscosity. By combining in silico predictions and experimental evaluations, we engineered variants with altered isoelectric points (pIs) of the Fab and VHH domains and characterized them across a broad, formulation-relevant pH range (pH 4.5-8.0). Our findings indicate that aligning slightly basic pI profiles (approximately 7.5-9.0) across variable domains within bispecific antibodies can effectively mitigate charge asymmetries in standard acidic formulations that may lead to unfavorable solution behavior. Importantly, rational design and early-stage experimental validation yielded optimized variants exhibiting significantly improved colloidal stability and viscosity compared to the starting molecule. This systematic study, the first of its kind for bispecific antibodies, highlights the value of integrating domain-level in silico assessments early in antibody design, facilitating efficient optimization toward improved solution behavior of multispecific biotherapeutics.

Several studies observed that biological removal of organic substances in biofilters during advanced wastewater treatment depends on the type of filter bed material. Even after long operation, granular activated carbon (GAC) filters showed superior removal of organic substances compared to biofilters with non-adsorbing filter bed materials, suggesting that enhanced biological activity may be the main driver for this observation. In this study, a one-dimensional (1D) continuum multispecies biofilm model coupled with multisolute adsorption of dissolved organic carbon (DOC) was developed to simulate a single biologically active GAC grain. Simulations with an impermeable, non-adsorbing grain were carried out for comparison. The results of this conceptual study demonstrated that adsorptive removal of biodegradable DOC did not influence biofilm development or its final microbial community composition (differences in volume fractions of active biofilm components were < 1.5 % with a total particulate volume fraction of 25 % in the biofilm). Even desorption of previously adsorbed biodegradable DOC, triggered by corresponding concentration gradients between the grain and the biofilm, had no significant effect, although up to 20 % of it was released in the simulated scenarios. This desorption was driven either by increasing biological activity during biofilm development or by sudden concentration changes in the bulk and was also influenced by the biofilm thickness. Overall, the biofilm thickness proved to be a decisive influencing factor. With increasing biofilm thickness, the models predicted increased biological activity and a more diverse microbial community composition, independent of adsorption or desorption processes. The simulation results therefore suggest that the increased biological activity observed in GAC systems does not result from adsorptive interactions between the GAC and biodegradable DOC. Other influencing factors such as protection against detachment, which leads to thicker biofilms, might play a more important role.