Frequency Doubling Nanocrystals for Cancer Theranostics

A novel bio-photonics approach based on the nonlinear optical process of second harmonic generation by non-centrosymmetric nanoparticles is presented and demonstrated on malignant human cell lines. The proposed method allows to directly interact with DNA in absence of photosensitizing molecules, to enable independent imaging and therapeutic modalities switching between the two modes of operation by simply tuning the excitation laser wavelength, and to avoid any risk of spontaneous activation by any natural or artificial light source.Comment: 16 pages, 7 figure

Contribution of polymeric materials to progress in xenotransplantation of microencapsulated cells - A review

Cell microencapsulation and subsequent transplantation of the microencapsulated cells require multidisciplinary approaches. Physical, chemical, biological, engineering, and medical expertise has to be combined. Several natural and synthetic polymeric materials and different technologies have been reported for the preparation of hydrogels, which are suitable to protect cells by microencapsulation. However, owing to the frequent lack of adequate characterization of the hydrogels and their components as well as incomplete description of the technology, many results of in vitro and in vivo studies appear contradictory or cannot reliably be reproduced. This review addresses the state of the art in cell microencapsulation with special focus on microencapsulated cells intended for xenotransplantation cell therapies. The choice of materials, the design and fabrication of the microspheres, as well as the conditions to be met during the cell microencapsulation process, are summarized and discussed prior to presenting research results of in vitro and in vivo studies. Overall, this review will serve to sensitize medically educated specialists for materials and technological aspects of cell microencapsulation

Synthesis strategies to extend the variety of alginate-based hybrid hydrogels for cell microencapsulation

The production of hydrogel microspheres (MS) for cell immobilization, maintaining the favorable properties of alginate gels but presenting enhanced performance in terms of in vivo durability and physical properties, is desirable to extend the therapeutic potential of cell transplantation. A novel type of hydrogel MS was produced by straightforward functionalization of sodium alginate (Na-alg) with heterotelechelic poly(ethylene glycol) (PEG) derivatives equipped with either end thiol or 1,2-dithiolane moieties. Activation of the hydroxyl moieties of the alginate backbone in the form of imidazolide intermediate allowed for fast conjugation to PEG oligomers through a covalent carbamate linkage. Evaluation of the modified alginates for the preparation of MS combining fast ionic gelation ability of the alginate carboxylate groups and slow covalentcross-linking provided by the PEG-end functionalities highlighted the influence of the chemical composition of the PEG-grafting units on the physical characteristics of the MS. The mechanical properties of the MS (resistance and shape recovery) and durability of PEG-grafted alginates in physiological environment can be adjusted by varying the nature of the end functionalities and the length of the PEG chains. In vitro cell microencapsulation studies and preliminary in vivo assessment suggested the potential of these hydrogels for cell transplantation applications

Simultaneous Multi-Harmonic Imaging of Nanoparticles in Tissues for Increased Selectivity

We investigate the use of Bismuth Ferrite (BFO) nanoparticles for tumor tissue labelling in combination with infrared multi-photon excitation at 1250 nm. We report the efficient and simultaneous generation of second and third harmonic by the nanoparticles. On this basis, we set up a novel imaging protocol based on the co-localization of the two harmonic signals and demonstrate its benefits in terms of increased selectivity against endogenous background sources in tissue samples. Finally, we discuss the use of BFO nanoparticles as mapping reference structures for correlative light-electron microscopy.Comment: 19 pages, 6 figure

Drug Screening Boosted by Hyperpolarized Long-Lived States in NMR

Transverse and longitudinal relaxation times (T1ρ and T1) have been widely exploited in NMR to probe the binding of ligands and putative drugs to target proteins. We have shown recently that long-lived states (LLS) can be more sensitive to ligand binding. LLS can be excited if the ligand comprises at least two coupled spins. Herein we broaden the scope of ligand screening by LLS to arbitrary ligands by covalent attachment of a functional group, which comprises a pair of coupled protons that are isolated from neighboring magnetic nuclei. The resulting functionalized ligands have longitudinal relaxation times T1(1H) that are sufficiently long to allow the powerful combination of LLS with dissolution dynamic nuclear polarization (D-DNP). Hyperpolarized weak “spy ligands” can be displaced by high-affinity competitors. Hyperpolarized LLS allow one to decrease both protein and ligand concentrations to micromolar levels and to significantly increase sample throughput

Hierarchical Quatsome-RGD Nanoarchitectonic Surfaces for Enhanced Integrin-Mediated Cell Adhesion

The synthesis and study of the tripeptide Arg-Gly-Asp (RGD), the binding site of different extracellular matrix proteins, e.g., fibronectin and vitronectin, has allowed the production of a wide range of cell adhesive surfaces. Although the surface density and spacing of the RGD peptide at the nanoscale have already shown a significant influence on cell adhesion, the impact of its hierarchical nanostructure is still rather unexplored. Accordingly, a versatile colloidal system named quatsomes, based on fluid nanovesicles formed by the self-assembling of cholesterol and surfactant molecules, has been devised as a novel template to achieve hierarchical nanostructures of the RGD peptide. To this end, RGD was anchored on the vesicle's fluid membrane of quatsomes, and the RGD-functionalized nanovesicles were covalently anchored to planar gold surfaces, forming a state of quasi-suspension, through a long poly(ethylene glycol) (PEG) chain with a thiol termination. An underlying self-assembled monolayer (SAM) of a shorter PEG was introduced for vesicle stabilization and to avoid unspecific cell adhesion. In comparison with substrates featuring a homogeneous distribution of RGD peptides, the resulting hierarchical nanoarchitectonic dramatically enhanced cell adhesion, despite lower overall RGD molecules on the surface. The new versatile platform was thoroughly characterized using a multitechnique approach, proving its enhanced performance. These findings open new methods for the hierarchical immobilization of biomolecules on surfaces using quatsomes as a robust and novel tissue engineering strategy.This work was supported by MICINN (PID2019-105622RBI00, MAT2016-80826-R, PID2019-111682RB-I00, PID2020-115296RA-I00, CTQ2015-66194-R; SAF2014-60138-R, RTI2018-093831-B-I00, and PDC2021-121481-I00); Instituto de Salud Carlos III (ISCIII) through the Networking Research Center on Bioengineering, Biomaterials and Nanomedicine, CIBER-BBN (FlexQS-skin, FlexCAB, BBN18PI01, BBN20PIV02, and CB/06/0074); Generalitat de Catalunya (grants 2017-SGR-918, 2017-SGR-229, 2017-SGR-1442, 2017-SGR-1439); the Fundació Marató de TV3 (Nr. 201812); the COST Action CA15126 Between Atom and Cell, and “ERDF A way of making Europe”. J.G. acknowledges financial support from the Ramón y Cajal Program (RYC-2017-22614) from MICINN and the Max Planck Society through the Max Planck Partner Group “Dynamic Biomimetics for Cancer Immunotherapy” in collaboration with the Max Planck Institute for Medical Research (Heidelberg, Germany). This work has received funding from the European Union’s Horizon 2020 research and innovation program through grant agreements 953110 (PHOENIX), 720942 (Smart4Fabry), 101007804 (MICRO4NANO), and 801342 (granted to the Agency for Business Competitiveness ACCIÓ through a Tecniospring Industry fellowship (TECSPR19-1-0065)). ICMAB acknowledges support from MICINN through the “‘Severo Ochoa”’ Programme for Centres of Excellence in R&D (CEX2019-000917-S). J.M. acknowledges a “Juan de la Cierva” fellowship from MICINN. J.T-M. acknowledges an FI-AGAUR grant (2020FI_B2 00137) from Generalitat de Catalunya and the European Social Fund. We also acknowledge the ICTS “NANBIOSIS for the support of the Synthesis of Peptides Unit (U3) at IQAC–CSIC (https://www.nanbiosis.es/portfolio/u3-synthesis-of-peptides-unit/) and the Biomaterial Processing and Nanostructuring Unit (U6) at ICMAB-CSIC (https://www.nanbiosis.es/portfolio/u6-biomaterial-processing-and-nanostructuring-unit/). We are grateful to the SMP unit of the Scientific and Technological Centers of University of Barcelona (CCiTUB). This work has been developed under the “Biochemistry, Molecular Biology and Biomedicine” and “Materials Science” Ph.D. programs of Universitat Autònoma de Barcelona (UAB).With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).Peer reviewe

Functionalization of Nanoparticles for Targeted Cancer Imaging and Diagnosis

At present time, cancer is the leading cause of death in developed countries. The medical imaging tools currently used in clinics such as radiology, nuclear magnetic resonance imaging, microscopy and endoscopy are not able to reach the sensitivity necessary to detect cancers in their earliest stages. The detection and identification of rare circulating individual cells and early cancer metastasis is of the utmost importance to reduce cancer mortality. The development of nanotechnology-based medical diagnostic tools could provide a qualitatively new level of sensitivity and accuracy for the detection of malignant diseases. In this project, the synthesis of functionalized nanoparticles with small targeting molecules that can capture cell entities for the detection of breast, lung and prostate cancers was thus investigated. The research project focused on the chemical development of coated and functionalized second harmonic nanoparticles, displaying unique optical properties. First, the synthesis of hetero-bifunctional poly(ethylene glycol) (PEG) able to covalently coat the nanomaterial and bind to the targeting molecules was performed. The coating of nanoparticles with α-triethoxysilyl-ω-azido and -ω-amino PEG was evaluated on iron oxide nanoparticles (IO NPs) as proof of concept. Coated NPs demonstrated to be non-cytotoxic and stable overtime in biological medium. Similar results were obtained with bismuth iron oxide NPs (BFO NPs) expressing second harmonic generation property. The functionalization of coated NPs was then established with drugs and ligands to specifically target cancer cells biomarkers. Preliminary modification of the selected ligands (e.g. c(RGDfK), Erlotinib, Lapatinib, and an inhibitor of prolyl-endopeptidases) with spacers and a biotin label was undertaken in order to assess their binding specificity to tumor cells. The two best candidates, c(RGDfK) and the inhibitor of prolyl-endopeptidases were modified to contain a simple or strain-cyclic alkyne for the conjugation to the NP's surface through bioorthogonal click reactions. Biological evaluations demonstrated that the ligand-functionalized IO and BFO NPs bind to human cancer cells through target-specific interactions. In summary, chemical modifications of nanoparticles were implemented using two different materials and several targeting ligands, demonstrating the flexibility of this methodology. Functionalized NPs were demonstrated to be biocompatible, stable over-time and suitable for the labelling of cancer cells through specific interactions with extracellular biomarkers overexpressed in tumors

Hydrogels based on functionalized polysaccharides

The present invention relates to functionalized hydrogel networks grafted with at least one moiety for use in numerous fields, from cosmetics to surgery and medicine

Hydrogels based on functionalized polysaccharides

The present invention relates to a functionalized hydrogel network grafted with at least one moiety for use in numerous fields, from cosmetics to surgery and medicine