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- Gene delivery into mesenchymal stem cells: a biomimetic approach using RGD nanoclusters based on poly(amidoamine) dendrimersPublication . Pandita, Deepti; Santos, José L.; Rodrigues, João; Pêgo, Ana P.; Granja, Pedro L.; Tomás, HelenaPoly(amidoamine) dendrimers (generations 5 and 6) with amine termini were conjugated with peptides containing the arginine-glycine-aspartic acid (RGD) sequence having in view their application as gene delivery vectors. The idea behind the work was to take advantage of the cationic nature of dendrimers and of the integrin targeting capabilities of the RGD motif to improve gene delivery. Dendrimers were used as scaffolds for RGD clustering and, by controlling the number of peptides (4, 8, and 16) linked to each dendrimer, it was possible to evaluate the effect of RGD density on the gene delivery process. The new vectors were characterized in respect to their ability to neutralize and compact plasmid DNA (pDNA). The complexes formed by the vectors and pDNA were studied concerning their size, zeta potential, capacity of being internalized by cells and ability of transferring genes. Transfection efficiency was analyzed, first, by using a pDNA encoding for Enhanced Green Fluorescent Protein and Firefly Luciferase and, second, by using a pDNA encoding for Bone Morphogenetic Protein-2. Gene expression in mesenchymal stem cells was enhanced using the new vectors in comparison to native dendrimers and was shown to be dependent on the electrostatic interaction established between the dendrimer moiety and the cell surface, as well as on the RGD density of nanoclusters. The use of dendrimer scaffolds for RGD cluster formation is a new approach that can be extended beyond gene delivery applications, whenever RGD clustering is important for modulating cellular responses.
- Amphiphilic polymer-mediated formation of laponite-based nanohybrids with robust stability and pH sensitivity for anticancer drug deliveryPublication . Wang, Guoying; Maciel, Dina; Wu, Yilun; Rodrigues, João; Shi, Xiangyang; Yuan, Yuan; Liu, Changsheng; Tomás, Helena; Li, YulinThe development of pH-sensitive drug delivery nanosystems that present a low drug release at the physiological pH and are able to increase the extent of the release at a lower pH value (like those existent in the interstitial space of solid tumors (pH 6.5) and in the intracellular endolysosomal compartments (pH 5.0)) is very important for an efficient and safe cancer therapy. Laponite (LP) is a synthetic silicate nanoparticle with a nanodisk structure (25 nm in diameter and 0.92 nm in thickness) and negative-charged surface, which can be used for the encapsulation of doxorubicin (DOX, a cationic drug) through electrostatic interactions and exhibit good pH sensitivity in drug delivery. However, the colloidal instability of LP still limits its potential clinical applications. In this study, we demonstrate an elegant strategy to develop stable Laponite-based nanohybrids through the functionalization of its surface with an amphiphile PEG-PLA copolymer by a self-assembly process. The hydrophobic block of PEG-PLA acts as an anchor that binds to the surface of drug-loaded LP nanodisks, maintaining the core structure, whereas the hydrophilic PEG part serves as a protective stealth shell that improves the whole stability of the nanohybrids under physiological conditions. The resulting nanocarriers can effectively load the DOX drug (the encapsulation efficiency is 85%), and display a pH-enhanced drug release behavior in a sustained way. In vitro biological evaluation indicated that the DOX-loaded nanocarriers can be effectively internalized by CAL-72 cells (an osteosarcoma cell line), and exhibit a remarkable higher anticancer cytotoxicity than free DOX. The merits of Laponite/PEG-PLA nanohybrids, such as good cytocompatibility, excellent physiological stability, sustained pH-responsive release properties, and improved anticancer activity, make them a promising platform for the delivery of other therapeutic agents beyond DOX.
- Gene delivery using dendrimer/pDNA complexes immobilized in electrospun fibers using the Layer-by-Layer techniquePublication . Ramalingam, Kirthiga; Castro, Rita; Pires, Pedro; Shi, Xiangyang; Rodrigues, João; Xiao, Shili; Tomás, HelenaA gene delivery platform for potential use in tissue engineering applications was developed by surface functionalization of biodegradable electrospun poly(lactic-co-glycolic acid) (PLGA) fibers with nanolayers of chitosan (cationic polymer) and alginate (anionic polymer) using the Layer-by-Layer (LbL) technique. The developed system not only supported the attachment and growth of human Mesenchymal Stem Cells (hMSCs), but also was capable of delivering pDNA/dendrimer complexes and inducing cell differentiation towards the osteogenic lineage when a pDNA codifying for human Bone Morphogenetic Protein-2 (BMP-2) was used. Beyond providing a means for pDNA/dendrimer complex immobilization, the polyelectrolyte coating conferred sustained release properties to the scaffold that resulted in pDNA protection from degradation. The polyelectrolyte coating, by itself, also contributed to enhance cell differentiation.
- Visible-light photolytic synthesis of multinuclear and dendritic iron-nitrile cationic complexesPublication . Ornelas, Cátia; Ruiz, Jaime; Rodrigues, João; Astruc, DidierMultinuclear and dendritic iron-nitrile piano-stool cationic complexes were synthesized in quantitative yield by a single-step synthesis involving visible-light photolysis of the complex [CpFe(eta(6)-toluene)][PF6]. This synthetic strategy was applied to mono-, bis- and tris-nitrile ligands and to new nitrile-terminated dendrimers containing 9, 27, and 81 tethers. All the synthesized products are deep red solids or red waxy products, highly stable to air and moisture. They were characterized by (1)H, (13)C, and (31)P NMR, elemental analysis, UV-vis spectroscopy, and cyclic voltammetry (single reversible oxidation wave to Fe(III)). Only the para-disubstituted arene dinitrile diiron complex shows two separated reversible waves indicating some electronic communication between the iron centers through the nitrile ligands.
- Self-assembled peptide nanoarchitectures: applications and future aspectsPublication . Sharma, Prem; Rathi, Brijesh; Rodrigues, João; Gorobets, NikolayAmong the diversity of natural and synthetic compounds being studied and applied for human welfare, peptides able to develop nanostructures are currently under special attention of scientists. In this review, we focus on such properties of peptides and various kinds of intramolecular interactions allowing their ability to form different shapes of nanoassemblies. We have also discussed the applications of self-assembled peptides in various biomedical fields where they can be employed as cargo to target delivery of drugs, genes, in tissue engineering, regenerative medicines, and biosensors.
- Superstructured poly(amidoamine) dendrimer-based nanoconstructs as platforms for cancer nanomedicine: a concise reviewPublication . Song, Cong; Shen, Mingwu; Rodrigues, João; Mignani, Serge; Majoral, Jean-Pierre; Shi, XiangyangPoly(amidoamine) (PAMAM) dendrimers, as a family of synthetic macromolecules with highly branched interiors, abundant surface functional groups, and well-controlled architecture, have received immense scientific and technological interests for a range of biomedical applications, in particular cancer nanome dicine. However, due to the drawbacks of single-generation dendrimers with a quite small size (e.g., gen eration 5 (G5) PAMAM dendrimer has a size of 5.4 nm) such as limited drug loading capacity, restricted tumor passive targeting based on enhanced permeability and retention effect, and lack of versatility to render them with stimuli-responsiveness, superstructured dendrimeric nanoconstructs (SDNs) have been designed to break through these obstacles in their applications in cancer nanomedicine. Here, we review the recent advances related to the creation of SDNs such as dendrimer dumbbells, core–shell tecto den drimers, dendrimer nanoclusters (NCs), dendrimer nanogels and dendrimer-templated hybrid NCs, and how these SDNs have been designed as nanoplatforms for different biomedical applications related to cancer nanomedicine including MR imaging, drug/gene delivery, combination therapy and theranostics. This review concisely describes the latest key developments in the field and also discusses the possible challenges and perspectives for translation applications.
- Recent therapeutic applications of the theranostic principle with dendrimers in oncologyPublication . Mignani, Serge; Rodrigues, João; Tomás, Helena; Caminade, Anne-marie; Laurent, Régis; Shi, Xiangyang; Majoral, Jean-PierreAt the intersection between treatment and diagnosis,nanoparticlestechnologiesarestronglyimpactingthe development of both therapeutic and diagnostic agents. Consequently, the development of novel modalities for concomitant noninvasive therapy and diagnostics known as theranostics as a single platform has gained significant interests. These multifunctional theranostic platforms include carbon-based nanomaterials (e.g., carbon nanotubes), drug conjugates, aliphatic polymers, micelles, vesicles, core-shell nanoparticles,microbubblesanddendrimersbearingdifferent contrastagentsanddrugs,suchascytotoxiccompoundsinthe oncology domain. Dendrimers emerged as a new class of highly tunable hyperbranched polymers, and have been developed as useful theranostic platforms. Magnetic resonance imaging, gamma scintigraphy, computed tomography and optical imaging are the main techniques developed with dendrimers in the theranostic domain in oncology. Different imaging agents have been used such as Gd(III), 19F, Fe2O3 (MRI), 76Br (PET), 111In, 88Y, 153Gd, 188Re, 131I (SPECT), 177Lu, gold (CT) and boronated groups, siliconnaphthalocyanines, dialkylcarbocyanines and QDs (optical imaging dyes).
- A fast responsive chromogenic and near-infrared fluorescence lighting-up probe for visual detection of toxic thiophenol in environmental water and living cellsPublication . Wu, Juanjuan; Su, Dongdong; Qin, Caiqin; Li, Wei; Rodrigues, João; Sheng, Ruilong; Zeng, LintaoThiophenols as high toxic environmental pollutants are poisonous for animals and aquatic organisms. Therefore, it is indispensable to monitor thiophenols in the environment. Herein, a novel near-infrared fluorescent probe was developed for the detection of thiophenols, which was easily prepared by one-step coupling of 2,4-dini trobenzenesulfonyl chloride with Nile blue. The probe showed a significant near infrared (∼675 nm) fluores cence “turn-on” response to thiophenols with some good features including chromogenic reaction, high sensi tivity and selectivity, fast response, near-infrared emission along with low detection limit (1.8 nM). The probe was employed to rapidly and visually determine thiophenols in several industrial wastewaters with good re coveries (90–110%). Moreover, this probe has been demonstrated good capability for imaging thiophenol in HeLa cells
- Antitumor efficacy of doxorubicin-loaded laponite/alginate hybrid hydrogelsPublication . Gonçalves, Mara; Figueira, Priscilla; Maciel, Dina; Rodrigues, João; Shi, Xiangyang; Tomás, Helena; Li, YulinDegradable hybrid hydrogels with improved stability are prepared by incorporating nanodisks of biocompatible laponite (LP) in alginate (AG) hydrogels using Ca2+ as a crosslinker. The Dox‐loaded hybrid hydrogels give a controlled Dox release at physiological environment in a sustained manner. Under conditions that mimic the tumor environment, both the sustainability in the Dox release (up to 17 d) and the release efficiency from LP/AG‐Dox hydrogels are improved. The in situ degradation of these hybrid hydrogels gives rise to nanohybrids that might serve as vehicles for carrying Dox through the cell membrane and diminish the effect of Dox ion‐trapping in the acidic extracellular environment of the tumor and/or in the endo‐lysosomal cell compartments.
- Engineered non-invasive functionalized dendrimer/dendron-entrapped/complexed gold nanoparticles as a novel class of theranostic (radio)pharmaceuticals in cancer therapyPublication . Mignani, Serge; Shi, Xiangyang; Ceña, Valentin; Rodrigues, João; Tomás, Helena; Majoral, Jean-PierreNanomedicine represents a very significant contribution in current cancer treatment; in addition to surgical intervention, radiation and chemotherapeutic agents that unfortunately also kill healthy cells, inducing highly deleterious and often life-threatening side effects in the patient. Of the numerous nanoparticles used against cancer, gold nanoparticles had been developed for therapeutic applications. Inter alia, a large variety of den drimers, i.e. soft artificial macromolecules, have turned up as non-viral functional nanocarriers for entrapping drugs, imaging agents, and targeting molecules. This review will provide insights into the design, synthesis, functionalization, and development in biomedicine of engineered functionalized hybrid dendrimer-tangled gold nanoparticles in the domain of cancer theranostic. Several aspects are highlighted and discussed such as 1) dendrimer-entrapped gold(0) hybrid nanoparticles for the targeted imaging and treatment of cancer cells, 2) dendrimer encapsulating gold(0) nanoparticles (Au DENPs) for the delivery of genes, 3) Au DENPs for drug delivery applications, 4) dendrimer encapsulating gold radioactive nanoparticles for radiotherapy, and 5) dendrimer/dendron-complexed gold(III) nanoparticles as technologies to take down cancer cells.