Biology subjects

Voutyritsa, E.

Publications and source records attributed to Voutyritsa, E..

3 recordsLinked to original sources

bioRxiv2025

Polymer functionalized liposomes as universal nanocarriers for drug delivery: Single particle insights on size-dependent performance and intracellular behavior

Nanomedicine requires smart delivery systems that are precise, robust, and universal. While liposomes are established vehicles in drug delivery, their full potential is challenged by limited stability, leakage, insufficient response and limited insight into particle size dependent performance. Here, we provide polymer-modified liposomes (PMLs), engineered for high structural integrity, broad cargo compatibility, and stimuli-responsive cargo release. We thoroughly characterize PMLs at the single particle level shedding light on key structure-function relationships within polydisperse formulations revealing that small vesicles (<100 nm) displayed significantly higher cargo packing densities, while release was independent of vesicle size. PMLs display high versatility effectively encapsulating cargo types ranging from positively or negatively charged small molecules, to oligonucleotides, and proteins. Studies on PMLs interaction with cell membrane show that PMLs maintain high internalization rate in HeLa and hCMEC/D3 brain cells and achieve [~]50% reduction in cell viability within 24 hours when loaded with the anticancer drug 5-fluorouracil. Finaly, PMLs successfully deliver siRNA targeting eGFP in HEK293-d2eGFP cells, achieving a 10-12% knockdown of eGFP expression, as resolved by machine learning-driven single-cell analysis. This work establishes a framework for PMLs high-resolution functional profiling and opens the way for the next generation rational design of tunable PMLs for drug delivery.

biophysics↗

bioRxiv2024

Direct observation of assembly and function of trigger responsive lipase biohybrids

Protein-polymer biohybrids mark a cutting edge in the creation of advanced materials designed for high performance under diverse conditions by combining the intrinsic stability and adaptability of synthetic polymers with the remarkable functionality and specificity of proteins. Despite the existence of stimuli responsive polymers, their potential for achieving precise, trigger responsive control over both the function and the assembly of protein-polymer biohybrids has yet to be fully attained. Here, we report the synthesis and thorough characterization of pH and temperature responsive lipase-polymer conjugates at both the supramolecular and the single molecule level. In contrast to conventional ensemble measurements performed in solution, we extensively characterized the stimuli triggered reversibility of the self-assembly of these lipase-based biohybrids and recorded the enzymatic activity at the fundamental level of individual nanoparticles. Our findings unexpectedly demonstrated that the stimuli responsive biohybrids exhibited not only a twofold increased enzymatic activity as compared to native lipases in certain cases but also maintained the trigger responsive control over enzymatic activity by temperature. Direct single particle recordings of biohybrid activity showed a correlation of the biohybrid size to catalytic activity, revealing individual enzymes to display higher activity in smaller nanoparticles. The biohybrids exhibit impressive long-term stability, in some cases almost 95% of the enzymatic activity as compared to [~]40-60% for native lipases after 1 year of storage. The improved stability and activity as compared to native enzymes accompanied with their triggered responsiveness highlight their significant potential for tightly controlled biocatalysis and sustainable industrial applications.

biophysics↗

bioRxiv2024

Proteolytic Performance is Dependent on Binding Efficiency, Processivity and Turnover: Single Protease Insights

Proteases are essential enzymes for a plethora of biological processes and biotechnological applications, e.g., within the dairy, pharmaceutical, and detergent industries. Decoding the molecular level mechanisms that drive protease performance is key to designing improved biosolutions. However, direct dynamic assessment of the fundamental partial reactions of substrate binding and activity has proven a challenge with conventional ensemble approaches. We developed a single-molecule (SM) assay for the direct and parallel recording of the stochastic binding interaction of Savinase, a serine-type protease broadly employed in biotechnology, with casein synchronously with monitoring proteolytic degradation of the substrate. SM recordings enabled us to determine how the overall activity of Savinase and two mutants relies on binding efficiency, enzymatic turnover and activity per binding event. Analysis of residence times revealed three characteristic binding states. Mutations were found to dominantly alter the likelihood of sampling the long lived state, with lifetimes longer than 30 seconds, indicating this state contributes to overall activity and supporting a level of processivity for Savinase. This observation challenges conventional expectations, as the protease has no characterized substrate binding site, or binding domain, aside from the active site. These insights, inaccessible through conventional assays, offer new perspectives for engineering proteases with improved hydrolytic performance.

biophysics↗