Engineering Osmo-DESs through computational screening and thermophysical validation for pharmaceutical technologies

Osmolyte-based Deep Eutectic Solvents (Osmo-DESs) inspired by biological systems are emerging as sustainable, biocompatible alternatives to conventional solvents for biomedical and pharmaceutical applications. In this study, we systematically investigate the thermophysical properties of multi-component Osmo-DESs based on naturally occurring metabolites, including amino-acids, sugars, sugar alcohols, and urea and trimethylamine N-oxide to mimic the complex intracellular environments found in nature. Using combinations of osmolytes, COSMO-RS computational screening and experimental validation employing polarized optical microscopy, Differential Scanning Calorimetry (DSC), and pH measurements we explore how increasing compositional complexity, from binary to multicomponent mixtures, including three-, four-, and six-component mixtures, influences thermophysical properties such as melting temperature (T m ), glass transition temperature (T g ), latent enthalpy of melting (ΔH m ), and pH. Our results demonstrate that multi-component Osmo-DESs exhibit highly tunable thermal behaviour governed by intricate hydrogen-bond networks, with water fraction playing a pivotal role in modulating phase transitions and stability. Amino-acid based Osmo-DESs, such as Proline:Betaine and Proline:Sarcosine, show significant depression of melting temperatures of −30.09°C and −28.93°C respectively at low water mole fractions, are consistent with strong eutectic interactions. The addition of further components, including sugar alcohols and sugars, enables fine-tuning of both thermal and pH properties, with certain combinations maintaining alkaline pH even at high hydration levels. Among the binary TMAO-based Osmo-DESs, TMAO: Gua exhibited the lowest peak melting temperature of −46.13 °C at a water mole fraction of 0.71, whereas the multicomponent bio-inspired T-Osmo-DESs containing TMAO, betaine, taurine, and urea reached a minimum peak melting temperature of −43.78 °C at a water mole fraction of 0.61, closely mimicking the protective environments of living cells. By bridging computational predictions with experimental insights, this work advances the rational design of sustainable, green Osmo-DESs tailored for a variety of applications including biomolecular stabilization. Our findings highlight the versatility and promise of Osmo-DESs as next-generation solvents, offering new opportunities for environmentally friendly and application-specific solutions in biotechnology and medicine.