Surface charge mediated cell-surface interaction on piezoelectric materials

Cell–material interactions play an essential role in the development of scaffold-based tissue engineering strategies. Cell therapies are still limited in treating injuries when severe damage causes irreversible loss of muscle cells. Electroactive biomaterials and, in particular, piezoelectric materials offer new opportunities for skeletal muscle tissue engineering since these materials have demonstrated suitable electroactive microenvironments for tissue development. In this study, the influence of the surface charge of piezoelectric poly(vinylidene fluoride) (PVDF) on cell adhesion was investigated. The cytoskeletal organization of C2C12 myoblast cells grown on different PVDF samples was studied by immunofluorescence staining, and the interactions between single live cells and PVDF were analyzed using an atomic force microscopy (AFM) technique termed single-cell force spectroscopy. It was demonstrated that C2C12 myoblast cells seeded on samples with net surface charge present a more elongated morphology, this effect being dependent on the surface charge but independent of the poling direction (negative or positive surface charge). It was further shown that the cell deadhesion forces of individual C2C12 cells were higher on PVDF samples with an overall negative surface charge (8.92 ± 0.45 nN) compared to those on nonpoled substrates (zero overall surface charge) (4.06 ± 0.20 nN). These findings explicitly demonstrate that the polarization/surface charge is an important parameter to determine cell fate as it affects C2C12 cell adhesion, which in turn will influence cell behavior, namely, cell proliferation and differentiationPortuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2019, UID/BIA/04050/2013, UID/BIO/04469, project POCI-01-0145-FEDER-028237 and under BioTecNorte operation (NORTE-01-0145-FEDER-000004). The authors also thank the FCT for the SFRH/BD/111478/2015 (S.R.) and SFRH/BPD/90870/2012 (C.R.) grants. Funds provided by FCT in the framework of EuroNanoMed 2016 call, Project LungChek ENMed/0049/2016 are also gratefully acknowledged. The authors acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) and from the Basque Government Industry and Education Department under the ELKARTEK, HAZITEK and PIBA (PIBA-2018-06

Lipid-based Nanocarriers for siRNA Delivery: challenges, strategies and the lessons learned from the DODAX: MO Liposomal System

The possibility of using the RNA interference (RNAi) mechanisms in gene therapy was one of the scientific breakthroughs of the last century. Despite the extraordinary therapeutic potential of this approach, the need for an efficient gene carrier is hampering the translation of the RNAi technology to the clinical setting. Although a diversity of nanocarriers has been described, liposomes continue to be one of the most attractive siRNA vehicles due to their relatively low toxicity, facilitated siRNA complexation, high transfection efficiency and enhanced pharmacokinetic properties. This review focuses on RNAi as a therapeutic approach, the challenges to its application, namely the nucleic acids’ delivery process, and current strategies to improve therapeutic efficacy. Additionally, lipid-based nanocarriers are described, and lessons learned from the relation between biophysical properties and biological performance of the dioctadecyldimethylammonium:monoolein (DODAX: MO) system are explored. Liposomes show great potential as siRNA delivery systems, being safe nanocarriers to protect nucleic acids in circulation, extend their half-life time, target specific cells and reduce off-target effects. Nevertheless, several issues related to delivery must be overcome before RNAi therapies reach their full potential, namely target-cell specificity and endosomal escape. Understanding the relationship between biophysical properties and biological performance is an essential step in the gene therapy field.This work was further supported by FEDER through POFC-COMPETE and by national funds from Fundacao para a Ciencia e a Tecnologia (FCT), through the projects PEst-OE/BIA/UI4050/2014 (CBMA) and PEst-C/FIS/UI0607/2013 (CFUM). Ana Oliveira was the recipient of a FCT scholarship (SFRH/BD/68588/2010). The authors would also like to acknowledge Andre Seixas Pereira for all the assistance with figures and graphs.info:eu-repo/semantics/publishedVersio

Stimuli-sensitive self-assembled tubules based on lysine-derived surfactants as nanocarriers for proteins

Drug delivery vectors based on amphiphilic molecules present considerable advantages, namely versatility in physicochemical properties and sensitivity to stimuli. Amino acid-based surfactants, in particular, are rather promising amphiphiles for this purpose1 because of their enhanced biocompatibility compared to conventional surfactants. In addition to forming micelles and vesicles, they can self-organize into other complex supramolecular structures, such as fibers, twisted ribbons, helical tapes and nanotubes.2,3 Herein, we have studied a family of novel anionic double-chained lysine-based surfactants, with variable degree of chain length mismatch. Because of their peculiar structure, these compounds are able to form in water tubular structures with assorted morphologies, as evidenced by video-enhanced light microscopy (VELM), scanning electron microscopy (SEM and cryo-SEM), cryogenic transmission electron microscopy (cryo-TEM) and atomic force microscopy (AFM).3 The loading ability of the tubules towards lysozyme, under varying experimental conditions, has been investigated inter alia by differential scanning microcalorimetry, gel electrophoresis and UV/VIS spectroscopy, with the goal of assessing the efficiency of these aggregates as pH- and temperature-sensitive nanocarriers for a model biomolecule. Results on the stability of the native and loaded tubules when in contact with different fluids (serum, artificial saliva, artificial sweat, blood), and on their toxicity in human cells, are also presented and discussed.FCT is gratefully acknowledged for financial support through Ph.D. grant SFRH/BD/108629/2015. CIQUP acknowledges financial support from FEDER/COMPETE and FCT through grants UID/QUI/00081/2013, POCI-01-0145-FEDER- 006980 and NORTE-01-0145-FEDER-000028

DODAB:MO versus novel liposomes for protein delivery: comparing toxicity and encapsulation efficiency

UID/BIA/04050/2019, funded by national funds through the FCT IP, and project FUN2CYT: Harnessing the potential for biomedical applications of pleiotropic cytokines LIF and oncostatin M (PTDC/BTM-MAT/30568/2017, POCI-01-0145-FEDER-030568) supported by POCI through FEDER and FCT IPinfo:eu-repo/semantics/publishedVersio

PVA-Based Hydrogels Loaded with Diclofenac for Cartilage Replacement

Polyvinyl alcohol (PVA) hydrogels have been widely studied for cartilage replacement due to their biocompatibility, chemical stability, and ability to be modified such that they approximate natural tissue behavior. Additionally, they may also be used with advantages as local drug delivery systems. However, their properties are not yet the most adequate for such applications. This work aimed to develop new PVA-based hydrogels for this purpose, displaying improved tribomechani- cal properties with the ability to control the release of diclofenac (DFN). Four types of PVA-based hydrogels were prepared via freeze-thawing: PVA, PVA/PAA (by polyacrylic acid (PAA) addition), PVA/PAA+PEG (by polyethylene glycol (PEG) immersion), and PVA/PAA+PEG+A (by annealing). Their morphology, water uptake, mechanical and rheological properties, wettability, friction coef- ficient, and drug release behavior were accessed. The irritability of the best-performing material was investigated. The results showed that the PAA addition increased the swelling and drug release amount. PEG immersion led to a more compact structure and significantly improved the material’s tribomechanical performance. The annealing treatment led to the material with the most suitable properties: besides presenting a low friction coefficient, it further enhanced the mechanical properties and ensured a controlled DFN release for at least 3 days. Moreover, it did not reveal irritability potential for biological tissues.info:eu-repo/semantics/publishedVersio

Fluorescence studies of benzothienoquinolines in lipid membranes

This work was funded by FCT-Portugal through CFUM, CQ-UM, research project PTDC/QUI/81238/2006 (cofinanced by FEDER/COMPETE, FCOMP-01-0124-FEDER-007467) and National NMR Network (Bruker 400). FCT is also acknowledged for Ph.D. grant of R. C. Calhelha (SFRH/BD/29274/2006)

Effective cytocompatible nanovectors based on serine-derived gemini surfactants and monoolein for small interfering RNA delivery

Supplementary data to this article can be found online athttps://doi.org/10.1016/j.jcis.2020.09.077.Non-viral gene therapy based on gene silencing with small interfering RNA (siRNA) has attracted great interest over recent years. Among various types of cationic complexation agents, amino acid-based surfactants have been recently explored for nucleic acid delivery due to their low toxicity and high biocompatibility. Monoolein (MO), in turn, has been used as helper lipid in liposomal systems due to its ability to form inverted nonbilayer structures that enhance fusogenicity, thus contributing to higher transfection efficiency. In this work, we focused on the development of nanovectors for siRNA delivery based on three gemini amino acid-based surfactants derived from serine (12Ser)2N12, amine derivative; (12Ser)2COO12, ester derivative; and (12Ser)2CON12, amide derivative individually combined with MO as helper lipid. The inclusion of MO in the cationic surfactant system influences the morphology and size of the mixed aggregates. Furthermore, the gemini surfactant:MO systems showed the ability to efficiently complex siRNA, forming stable lipoplexes, in some cases clearly depending on the MO content, without inducing significant levels of cytotoxicity. High levels of gene silencing were achieved in comparison with a commercially available standard indicating that these gemini:MO systems are promising candidates as lipofection vectors for RNA interference (RNAi)-based therapies.The authors acknowledge Fundação para a Ciência e a Tecnolo-gia (FCT) for financial support through projects UIDB/00081/2020 and UIDB/50006/2020. This work was supported by the‘‘Contrato-Programa” UIDB/04050/2020 funded by national fundsthrough the FCT I.P. Dr. Marisa Passos is gratefully acknowledged for help with the statistical analysis of cytotoxicity data. Fundingby the CCDR-N/NORTE2020/Portugal2020 through project DESign-BIOtechHealth (ref. Norte-01-0145-FEDER-000024) is also acknowledged. I. S. Oliveira and S.G. Silva also acknowledge finan-cial support from FCT through PhD grant SFRH/BD/108629/2015 and Individual Call to Scientific Employment Stimulus - CEEC Indi-vidual grant CEECIND/01932/2017, respectivelyinfo:eu-repo/semantics/publishedVersio

Interaction of benzothienoquinolines with DNA and lipid membranes monitored by fluorescence

RICI4 - Book of AbstractsThis work was funded by FCT-Portugal through CFUM, CQ-UM, research project PTDC/QUI/81238/2006 (cofinanced by FEDER/COMPETE, FCOMP-01-0124-FEDER-007467). R.C.C. acknowledges FCT the post-doctoral grant (SFRH/BPD/68344/2010

Fluorescence studies of potential antitumoral 6-heteroarylthieno[3,2-b]pyridines in solution and in nanoliposomes

Fluorescence properties of new potential antitumoral 6-heteroarylthieno[3,2-b]pyridines, recently synthesized, were studied in solution and in nanoliposomes of different compositions. The results indicate that these compounds can be transported in the hydrophobic region of the lipid bilayer. The liposomal formulation Egg-PC:Ch:DPPG (7:3:1) is the one with smaller size and lowest polydispersity.CFUM - PEst-C/FIS/UI0607/2011 (F-COMP-01-0124-FEDER-022711)Fundação para a Ciência e a Tecnologia - SFRH/BD/47052/2008)CQ/UM - PEst-C/QUI/UI0686/2011 (FCOMP-01-0124-FEDER-022716), PTDC/QUI/81238/2006 (FCOMP-01-0124-FEDER-007467)FEDE

Higher number of Helicobacter pylori CagA EPIYA C phosphorylation sites increases the risk of gastric cancer, but not duodenal ulcer

<p>Abstract</p> <p>Background</p> <p><it>Helicobacter pylori </it>infection is one of the most common infections worldwide and is associated with gastric cancer and peptic ulcer. Bacterial virulence factors such as CagA have been shown to increase the risk of both diseases. Studies have suggested a causal role for CagA EPIYA polymorphisms in gastric carcinogenesis, and it has been shown to be geographically diverse. We studied associations between <it>H. pylori </it>CagA EPIYA patterns and gastric cancer and duodenal ulcer, in an ethnically admixed Western population from Brazil. CagA EPIYA was determined by PCR and confirmed by sequencing. A total of 436 patients were included, being 188 with gastric cancer, 112 with duodenal ulcer and 136 with gastritis.</p> <p>Results</p> <p>The number of EPIYA C segments was significantly associated with the increased risk of gastric carcinoma (OR = 3.08, 95% CI = 1.74 to 5.45, p < 10^-3) even after adjustment for age and gender. Higher number of EPIYA C segments was also associated with gastric atrophy (p = 0.04) and intestinal metaplasia (p = 0.007). Furthermore, patients infected by <it>cag</it>A strains possessing more than one EPIYA C segment showed decreased serum levels of pepsinogen I in comparison with those infected by strains containing one or less EPIYA C repeat. Otherwise, the number of EPIYA C segments did not associate with duodenal ulcer.</p> <p>Conclusions</p> <p>Our results demonstrate that infection with <it>H. pylori </it>strains harbouring more than one CagA EPIYA C motif was clearly associated with gastric cancer, but not with duodenal ulcer.</p> <p>Higher number of EPIYA C segments was also associated with gastric precancerous lesions as demonstrated by histological gastric atrophic and metaplastic changes and decreased serum levels of pepsinogen I.</p