How Microgels Can Improve the Impact of Organ-on-Chip and Microfluidic Devices for 3D Culture: Compartmentalization, Single Cell Encapsulation and Control on Cell Fate.

The Organ-on-chip (OOC) devices represent the new frontier in biomedical research to produce micro-organoids and tissues for drug testing and regenerative medicine. The development of such miniaturized models requires the 3D culture of multiple cell types in a highly controlled microenvironment, opening new challenges in reproducing the extracellular matrix (ECM) experienced by cells in vivo. In this regard, cell-laden microgels (CLMs) represent a promising tool for 3D cell culturing and on-chip generation of micro-organs.

Repeated oral administration of low doses of silver in mice: tissue distribution and effects on central nervous system.

Background: Widespread use of silver in its different forms raises concerns about potential adverse effects after ingestion, the main exposure route for humans. The aim of this study was to investigate in CD-1 (ICR) male mice the tissue distribution and in vivo effects of 4-week oral exposure to 0.25 and 1 mg Ag/kg bw 10 nm citrate coated silver nanoparticles (AgNPs) and 1 mg Ag/kg bw silver acetate (AgAc) at the end of treatment (EoT) and after 4 weeks of recovery.

Calcium Stearate as an Effective Alternative to Poly(vinyl alcohol) in Poly-Lactic-co-Glycolic Acid Nanoparticles Synthesis.

Poly(d,l-lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) are among the most studied systems for drug and gene targeting. So far, the synthesis of stable and uniform PLGA NPs has involved the use of a large excess of polyvinyl surfactants such as poly(vinyl alcohol) (PVA) and polyvinylpyrrolidone (PVP), whose removal requires multistep purification procedures of high ecological and economic impact. Hence the development of environment-friendly and cost-effective synthetic procedures for the synthesis of PLGA NPs would effectively boost their use in clinics.

Photocrosslinked poly(amidoamine) nanoparticles for central nervous system targeting.

This study presents an innovative method for the synthesis of polymeric nanoparticles (NPs) for central nervous system (CNS) targeting. The method is based on Ultraviolet light (UV)-induced crosslinking of diacrylamide-terminated oligomers of poly(amidoamine)s (PAAs), a widely used class of synthetic polymers in biomedical field research, especially in drug delivery thanks to their excellent biocompatibility and controlled biodegradability. Previous attempts aiming at preparing PAA-based NPs by self-assembly were challenged by lack of structural stability and consequently their early degradation and premature drug release.

Tissue distribution and acute toxicity of silver after single intravenous administration in mice: nano-specific and size-dependent effects.

Background: Silver nanoparticles (AgNPs) are an important class of nanomaterials used as antimicrobial agents for a wide range of medical and industrial applications. However toxicity of AgNPs and impact of their physicochemical characteristics in in vivo models still need to be comprehensively characterized. The aim of this study was to investigate the effect of size and coating on tissue distribution and toxicity of AgNPs after intravenous administration in mice, and compare the results with those obtained after silver acetate administration.

Versatile fabrication of vascularizable scaffolds for large tissue engineering in bioreactor.

Despite significant progresses were achieved in tissue engineering over the last 20 years, a number of unsolved problems still remain. One of the most relevant issues is the lack of a proper vascularization that is limiting the size of the engineered tissues to smaller than clinically relevant dimensions. Sacrificial molding holds great promise to engineered construct with perfusable vascular architectures, but there is still the need to develop more versatile approaches able to be independent of the nature and dimensions of the construct.

Enzyme-responsive multifunctional surfaces for controlled uptake/release of (bio)molecules.

The current trend in the development of biomaterials is towards bioactive and biodegradable systems. In particular, enzyme-responsive structures are useful tools to realize biodegradable surfaces for the controlled delivery of biomolecules/drugs through a triggered surface erosion process. Up to now, enzyme-responsive structures have been designed by covalent linkage between synthetic polymers and biodegradable functionalities that are responsive to chemical and biological cues (i.

Poly(amido-amine)-based hydrogels with tailored mechanical properties and degradation rates for tissue engineering.

Poly(amido-amine) (PAA) hydrogels containing the 2,2-bisacrylamidoacetic acid-4-amminobutyl guanidine monomeric unit have a known ability to enhance cellular adhesion by interacting with the arginin-glycin-aspartic acid (RGD)-binding αVβ3 integrin, expressed by a wide number of cell types. Scientific interest in this class of materials has traditionally been hampered by their poor mechanical properties and restricted range of degradation rate. Here we present the design of novel biocompatible, RGD-mimic PAA-based hydrogels with wide and tunable degradation rates as well as improved mechanical and biological properties for biomedical applications.

pH controlled staining of CD4(+) and CD19(+) cells within functionalized microfluidic channel.

Herein proposed is a simple system to realize hands-free labeling and simultaneous detection of two human cell lines within a microfluidic device. This system was realized by novel covalent immobilization of pH-responsive poly(methacrylic acid) microgels onto the inner glass surface of an assembled polydimethylsiloxane/glass microfluidic channel. Afterwards, selected thiophene labeled monoclonal antibodies, specific for recognition of CD4 antigens on T helper/inducer cells and CD19 antigens on B lymphocytes cell lines, were encapsulated in their active state by the immobilized microgels.

Multifunctional nanostructures based on inorganic nanoparticles and oligothiophenes and their exploitation for cellular studies.

The combination of materials that possess different properties (such as, for instance, fluorescence and magnetism) into one single object of nanoscale size represents an attractive challenge for biotechnology, especially for their potential relevance in biomedical applications. We report here the preparation of novel bifunctional conjugates based on the linkage of inorganic nanoparticles to organic oligothiophene fluorophores (OTFs). In comparison to the organic dyes commonly used in bioimaging and more similarly to colloidal quantum dots, OTFs have broad optical absorption spectra, and therefore OTF fluorophores emitting at different colors can be excited with a single excitation source, allowing for easier multiplexing analysis.