Biology subjects

Pujals, S.

Publications and source records attributed to Pujals, S..

3 recordsLinked to original sources

bioRxiv2023

Reaching the tumor: mobility of polymeric micelles inside an in vitro tumor-on-a-chip model with dual ECM

Degradable polymeric micelles are promising drug delivery systems due to their hydrophobic core and responsive design. When applying micellar nanocarriers for tumor delivery, one of the bottlenecks encountered in vivo is the tumor tissue barrier - crossing the dense mesh of cells and extracellular matrix (ECM). Sometimes overlooked, the extracellular matrix can trap nanoformulations based on charge, size and hydrophobicity. Here we used a simple design of a microfluidic chip with two types of ECM and MCF7 spheroids to allow "high throughput" screening of the interactions between biological interfaces and polymeric micelles. To demostrarte the applicapility of the chip, a small library of fluorescently labelled polymeric micelles varying in their hydrophilic shell and hydrophobic core forming blocks was studied. Three widely used hydrophilic shells were tested and compared, poly(ethylene glycol), poly(2-ethyl-2-oxazoline), and poly(acrylic acid), along with two enzyamticaly degradable dendritic hydrophobic cores (based on Hexyl or Nonyl end-gorups). Using ratiometric imaging of unimer:micelle fluorescence and FRAP inside the chip model, we obtained the local assembly state and dynamics inside the chip. Notably, we observed different micelle behaviors in the basal lamina ECM, from avoidance of ECM structure to binding of the poly(acrylic acid) formulations. Binding to basal lamina correlated with higher uptake into MCF7 spheroids. Overall, we proposed a simple microfluidic chip containing dual ECM and spheroids for the assessment of the interactions of polymeric nanocarrires with biological interfaces and evaluating nanoformulations capacity to cross the tumor tissue barrier.

bioengineering↗

bioRxiv2020

The ESCRT-III machinery participates in the production of extracellular vesicles and protein export during Plasmodium falciparum infection

Infection with Plasmodium falciparum enhances extracellular vesicles (EVs) production in parasitized red blood cells (pRBC), an important mechanism for parasite-to-parasite communication during the asexual intraerythrocytic life cycle. The endosomal sorting complex required for transport (ESCRT), and in particular the ESCRT-III sub-complex, participates in the formation of EVs in higher eukaryotes. However, RBCs have lost the majority of their organelles through the maturation process, including an important reduction in their vesicular network. Therefore, the mechanism of EV production in P. falciparum-infected RBCs remains to be elucidated. Here we demonstrate that P. falciparum possesses a functional ESCRT-III machinery that is activated by an alternative recruitment pathway involving the action of PfBro1 and PfVps32/PfVps60 proteins. Additionally, multivesicular bodies formation and membrane shedding, both reported mechanisms of EVs production, were reconstituted in the membrane model of giant unilamellar vesicles using the purified recombinant proteins. Moreover, the presence of PfVps32, PfVps60 and PfBro1 in EVs purified from a pRBC culture was confirmed by super-resolution microscopy. In accordance, disruption of the Pfvps60 gene led to a reduction in the number of the produced EVs in the KO strain when compared with the parental 3D7 strain. Overall, our results increase the knowledge on the underlying molecular mechanisms during malaria pathogenesis and demonstrate that ESCRT-III P. falciparum proteins participate in EVs production.

microbiology↗

bioRxiv2020

Real-time Ratiometric Imaging of Micelles Assembly State in a Microfluidic Cancer-on-a-chip

The performance of supramolecular nanocarriers as drug delivery systems depends on their stability in the complex and dynamic biological media. After administration, nanocarriers are challenged by confronting different barriers such as shear stress and proteins present in blood, endothelial wall, extracellular matrix and eventually cancer cell membranes. While early disassembly will result in a premature drug release, extreme stability of the nanocarriers can lead to poor drug release and low efficiency. Therefore, comprehensive understanding of the stability and assembly state of supramolecular carriers in each stage of delivery is a key factor for the rational design of these systems. One of the key challenges is that current 2D in vitro models do not provide exhaustive information, as they do not fully recapitulate the 3D tumor microenvironment. This deficiency of the 2D models complexity is the main reason for the differences observed in vivo when testing the performance of supramolecular nanocarriers. Herein, we present a real-time monitoring study of self-assembled micelles stability and extravasation, combining spectral confocal microscopy and a microfluidic tumor-on-a-chip. The combination of advanced imaging and a reliable organ-on-a-chip model allow us to track micelle disassembly by following the spectral properties of the amphiphiles in space and time during the crucial steps of drug delivery. The spectrally active micelles were introduced under flow and their position and conformation followed during the crossing of barriers by spectral imaging, revealing the interplay between carrier structure, micellar stability and extravasation. Integrating the ability of the micelles to change their fluorescent properties when disassembled, spectral confocal imaging and 3D microfluidic tumor blood vessel-on-a-chip, resulted in the establishment of a robust testing platform, suitable for real-time imaging and evaluation of supramolecular drug delivery carriers stability.

bioengineering↗