Biology subjects

Meinel, L.

Publications and source records attributed to Meinel, L..

3 recordsLinked to original sources

bioRxiv2026

Exploring lipid nanoparticle design spaces using self-regulating microfluidic machines and multiplexed in vivo biodistribution

Delivering therapeutic mRNA relies on lipid nanoparticles (LNPs). Finding optimal process parameters for new lipid combinations in LNP formulations remains a challenge. In our work, we used an automated, self-regulating microfluidic platform that actively changes process parameters to tune LNP formulations for preset, desired quality standards. We tested new LNPs by swapping poly(ethylene glycol) (PEG) lipopolymers for alternatives based on poly(2-methyl-2-oxazoline) (PMeOx) and poly(2-ethyl-2-oxazoline) (PEtOx). For each lipopolymer variant, the platform independently identified optimal production conditions in four or fewer iterative cycles, yielding particles of the preset size and high mRNA encapsulation. Small-angle X-ray scattering revealed that smaller LNPs modified with PEtOx had more structural surface variety and higher mRNA loading efficiency. When multiplexing these formulations in mice, the PEtOx-containing LNPs accumulated more in bone marrow compared to those with PEG, indicating trends that the chemistry of the lipopolymer affects the biodistribution of the resulting LNPs. By combining automated formulation and in vivo multiplexed testing, our approach provides a practical way to rapidly plan, formulate, and evaluate large pharmaceutical design spaces, to select excipients and process parameters yielding optimal biological performance of LNPs. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=76 SRC="FIGDIR/small/729611v1_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@1a08b68org.highwire.dtl.DTLVardef@120724corg.highwire.dtl.DTLVardef@12fed98org.highwire.dtl.DTLVardef@197aa41_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2024

Beyond comparison: Brillouin microscopy and AFM-based indentation reveal divergent insights into the mechanical profile of the murine retina

Mechanical tissue properties increasingly serve as pivotal phenotypic characteristics that are subject to change during development or pathological progression. The quantification of such material properties often relies on physical contact between a load-applying probe and an exposed sample surface. For most tissues, these requirements necessitate animal sacrifice, tissue dissection and sectioning. These invasive procedures bear the risk of yielding mechanical properties that do not portray the physiological mechanical state of a tissue within a functioning organism. Brillouin microscopy has emerged as a non-invasive, optical technique that allows to assess mechanical cell and tissue properties with high spatio-temporal resolution. In optically transparent specimens, this technique does not require animal sacrifice, tissue dissection or sectioning. However, the extent to which results obtained from Brillouin microscopy allow to infer conclusions about potential results obtained with a contact-based technique, and vice versa, is unclear. Potential sources for discrepancies include the varying characteristic temporal and spatial scales, the directionality of measurement, environmental factors, and mechanical moduli probed. In this work, we addressed those aspects by quantifying the mechanical properties of acutely dissected murine retinal tissues using Brillouin microscopy and atomic force microscopy (AFM)-based indentation measurements. Our results show a distinct mechanical profile of the retinal layers with respect to the Brillouin frequency shift, the Brillouin linewidth and the apparent Youngs modulus. Contrary to previous reports, our findings do not support a simple correlative relationship between Brillouin frequency shift and apparent Youngs modulus. Additionally, the divergent sensitivity of Brillouin microscopy and AFM-indentation measurements to cross-linking or changes post mortem underscores the dangers of assuming both methods can be generally used interchangeably. In conclusion, our study advocates for viewing Brillouin microscopy and AFM-based indentation measurements as complementary tools, discouraging direct comparisons a priori and suggesting their combined use for a more comprehensive understanding of tissue mechanical properties.

biophysics↗

bioRxiv2023

Deprivation of arginine and lysine interferes with growth of patient-derived tumor xenografts

In recent years, a novel treatment method for cancer emerged, which is based on the starvation of tumors of amino acids like arginine. The deprivation of arginine in serum is based on enzymatic degradation and can be realized by arginine deaminases like the L-amino acid oxidase found in the ink toxin of the sea hare Aplysia punctata. Previously isolated from the ink, the L-amino acids oxidase was described to oxidate the essential amino acid L-lysine and L-arginine to their corresponding deaminated alpha-keto acids. Here, we present the recombinant production and functionalization of amino acid oxidase Aplysia Punctata ink toxin (APIT). PEGylated APIT (APIT-PEG) increased the blood circulation time. APIT-PEG treatment of patient-derived xenografted mice shows a significant dose dependent reduction of tumor growth over time mediated by amino acid starvation of the tumor. Treatment of mice with APIT-PEG which lead to deprivation of arginine was well tolerated.

cancer biology↗