1,721,048 research outputs found
Advances in Drug Delivery and Biomaterials: Facts and Vision
Full text linkDrug delivery and biomaterials are different fields of science but, at the same time, are tightly related and intertwined. The 2018 CRS Italy Chapter Annual Workshop aims to explore recent advances in design and development in these areas. Many colleagues from Europe participated to the Workshop, stimulating the discussion. To foster the discussion on recent research and networking opportunities, especially among younger attendees, all poster-presenting authors were asked to provide a short talk. The very friendly and stimulating atmosphere allowed the attendees to explore new frontiers and tackle new horizons
Cyclodextrin/PEG based hydrogels for multi-drug delivery
No full textCyclodextrin–PEG hydrogels were prepared by reaction of hexamethlyene isocyanate-activated -cyclodextrins with 1.9 kDa NH2 PEG NH2. The reaction was carried out in anhydrous dimethylsulfoxide by using 0.25:1, 0.33:1, 0.5:1, 0.67:1, 1:1, and 2:1 CD/PEG molar ratios. The addition of acetic acid to the reaction mixture was found to slow the cross-linking reaction, yielding homogeneous matrices. The mechanical characterization indicated that the elasticity of the matrices increased as the CD content in the hydrogel increased while the elongation was irrespective of the hydrogel composition. By incubation in water and ethanol, the hydrogels underwent complete swelling in 5–10 min. The water up-take increased logarithmically as the CD/PEG ratio decreased to reach a swelling degree of 800% (swollen hydrogel/dry hydrogel, w/w%). The ethanol uptake increased with a power correlation as the CD/PEG ratio decreased to reach a swelling degree of about 1000% with 0.25:1 CD/PEG hydrogel. Lysozyme, -estradiol, and quinine were loaded by swell embedding. The lysozyme loading increased as the CD/PEG ratio decreased while the incorporation of -estradiol and quinine displayed inverse correlation with respect to the CD/PEG ratio. The maximal incorporation (loaded drug/dry hydrogel, w/w%) for lysozyme, -estradiol and quinine was 2, 0.6, and 2.4%, respectively. Lysozyme was quickly released from the matrices, and the release was faster as the CD/PEG ratio decreased. Also, -estradiol and quinine release rates were inversely proportional to the CD/PEG ratio, but in these cases, the release profiles were strongly affected by the drug interaction with the hexamethylated -cyclodextrins in the matrices
Recent Advances in Understanding the Protein Corona of Nanoparticles and in the Formulation of “Stealthy” Nanomaterials
Full text linkIn the last decades, the staggering progress in nanotechnology brought around a wide and heterogeneous range of nanoparticle-based platforms for the diagnosis and treatment of many diseases. Most of these systems are designed to be administered intravenously. This administration route allows the nanoparticles (NPs) to widely distribute in the body and reach deep organs without invasive techniques. When these nanovectors encounter the biological environment of systemic circulation, a dynamic interplay occurs between the circulating proteins and the NPs, themselves. The set of proteins that bind to the NP surface is referred to as the protein corona (PC). PC has a critical role in making the particles easily recognized by the innate immune system, causing their quick clearance by phagocytic cells located in organs such as the lungs, liver, and spleen. For the same reason, PC defines the immunogenicity of NPs by priming the immune response to them and, ultimately, their immunological toxicity. Furthermore, the protein corona can cause the physical destabilization and agglomeration of particles. These problems induced to consider the PC only as a biological barrier to overcome in order to achieve efficient NP-based targeting. This review will discuss the latest advances in the characterization of PC, development of stealthy NP formulations, as well as the manipulation and employment of PC as an alternative resource for prolonging NP half-life, as well as its use in diagnostic applications
Enzyme modification by MPEG with an amino acid or peptide as spacer arms
No full textA method for the modification of enzymes by MPEG carrying an amino acid or peptide as a spacer arm is described and tested with aliphatic or aromatic side chains amino acids. The procedure involves MPEG activation by p-nitrophenylchloroformate for the amino acid or peptide coupling that is in turn activated for the protein binding. The advantage of the method resides in the possibility to introduce proper reporter groups between the polymer and the protein as norleucine for a direct evaluation of the bound polymer chains, tryptophan for structural studies of the polymer-protein adduct, and radioactive amino acid for pharmacokinetic investigations. The method was positively tested with arginase, ribonuclease, and superoxide dismutase as enzymes of therapeutic value. © 1991 Humana Press Inc
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Latest Advances in Biomimetic Cell Membrane-Coated and Membrane-Derived Nanovectors for Biomedical Applications
Full text linkIn the last decades, many nanovectors were developed for different diagnostic or therapeutic purposes. However, most nanosystems have been designed using a “bottom-up” approach, in which the basic components of the nanovector become assembled to achieve complex and specific behaviors. Despite the fine control of formulative conditions, the complexity of these systems often results cumbersome and difficult to scale-up. Recently, biomimetic materials emerged as a complementary or alternative design approach through a “top-down strategy”, using cell-derived materials as building blocks to formulate innovative nanovectors. The use of cell membranes as nanoparticle coatings endows nanomaterials with the biological identity and some of the functions of the cells they are derived from. In this review, we discuss some of the latest examples of membrane coated and membrane-derived biomimetic nanomaterials and underline the common general functions offered by the biomaterials used. From these examples, we suggest a systematic classification of these biomimetic materials based on their biological sources and formulation techniques, with their respective advantages and disadvantages, and summarize the current technologies used for membranes isolation and integration on nanovectors. We also discuss some current technical limitations and hint to future direction of the improvement for biomimetics
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