Supercritical CO2-assisted spray drying of strawberry-like gold-coated magnetite nanocomposites in chitosan powders for inhalation

Associate Laboratory Research Unit for Green Chemistry Clean Processes and Technologies-LAQV - (UID/QUI/50006/2013) ; UCIBIO from FCT/MEC - UID/Multi/04378/2013 ; ERDF - POCI-01-0145-FEDER-007265; FCT/MEC - SFRH/BD/51584/2011; SFRH/BPD/93982/2013 ; FCT-Lisbon - IF/00915/2014Lung cancer is one of the leading causes of death worldwide. Therefore, it is of extreme importance to develop new systems that can deliver anticancer drugs into the site of action when initiating a treatment. Recently, the use of nanotechnology and particle engineering has enabled the development of new drug delivery platforms for pulmonary delivery. In this work, POXylated strawberry-like gold-coated magnetite nanocomposites and ibuprofen (IBP) were encapsulated into a chitosan matrix using Supercritical Assisted Spray Drying (SASD). The dry powder formulations showed adequate morphology and aerodynamic performances (fine particle fraction 48%-55% and aerodynamic diameter of 2.6-2.8 μm) for deep lung deposition through the pulmonary route. Moreover, the release kinetics of IBP was also investigated showing a faster release of the drug at pH 6.8, the pH of lung cancer. POXylated strawberry-like gold-coated magnetite nanocomposites proved to have suitable sizes for cellular internalization and their fluorescent capabilities enable their future use in in vitro cell based assays. As a proof-of-concept, the reported results show that these nano-in-micro formulations could be potential drug vehicles for pulmonary administration. © 2017 by the authors.publishersversionpublishe

Enhancing the teaching-research nexus in the undergraduate curriculum through assessment

Successful linkages between teaching and research in the undergraduate curriculum are strongly dependent on academics’ ability to encourage and facilitate an inquiry based approach to learning. An assessment strategy in which students become active participants in the assessment process is crucial to facilitate the development of this inquiry based approach. Developing this so-called research-mindedness is central to helping students' to become independent learners and to be more effective professionals in their future careers. This paper describes a distributed systems approach to assessment implemented in the undergraduate module Molecular Biology. The assessment comprised a series of sequence identification, database use and analysis steps, with each student being given a different starting gene. In combination, the students analysed an entire genetic pathway. This approach allows the assignments generated to be combined and used to address a single larger question, which can be either teaching or research based. This is then fed back into the teaching. This direct link between the assessment outcomes and the learning process increases student engagement with the subject and sense of ownership of the work carried out. This approach to assessment, in which students undertake a small part of a larger task, is ideal for various technical, skills-based, assignments, such as those central to the many types of bioinformatics analyses. However, it can be adapted to various types of meta-review. The paper discusses the details for the implementation, as well as the benefits and potential pitfalls of the approach

Intramolecular excimer formation and sensing behavior of new fluorimetric probes and their interactions with metal cations and barbituric acids

A new family of compounds able to promote host-guest interactions with specific molecules (e.g., cyanuric and parabanic acids) and to coordinate metal ions, namely Zn(II) and Cu(II), has been synthesized and fully characterized. The new probes derive from the attachment of two methylaminopyrene units to the carbonyl precursor 2,6-bis(2-formylphenoxymethyl)pyridine.http://www.sciencedirect.com/science/article/B6THH-4HF5KD3-1/1/ef66847d1e019d05e2068bef93cfbd9

Long Range Electron Transfer Quenching in Polyamine Chains Bearing a Terminal Naphthalene Unit

The fluorescence emission of a naphthalene unit attached to a polyamine chain is quenched by intramolecular electron transfer from the deprotonated amines to the excited fluorophore. Measurements of the respective quenching rate constants as a function of the distance, reveal an exponential dependence with β = 0.45 Å-1. Identical measurements carried out in deuterated water have shown a similar dependence with the distance β = 0.49 Å-1 but an average reduction of the absolute values of the rate constants of ca. 1.2. The polyamine chains seem to constitute a bridge through which the electron can find a route to its movement, more efficiently than through space

Atomic scale model and electronic structure of Cu2_2O/CH3_3NH3_3PbI3_3 interfaces in perovskite solar cells

Cuprous oxide has been conceived as a potential alternative to traditional organic hole transport layers in hybrid halide perovskite-based solar cells. Device simulations predict record efficiencies using this semiconductor, but experimental results do not yet show this trend. More detailed knowledge about the Cu$_2$O/perovskite interface is mandatory to improve the photoconversion efficiency. Using density functional theory calculations, here we study the interfaces of CH$_3$NH$_3$PbI$_3$ with Cu$_2$O to assess their influence on device performance. Several atomistic models of these interfaces are provided for the first time, considering different compositions of the interface atomic planes. The interface electronic properties are discussed on the basis of the optimal theoretical situation, but in connection with the experimental realizations and device simulations. It is shown that the formation of vacancies in the Cu$_2$O terminating planes is essential to eliminate dangling bonds and trap states. The four interface models that fulfill this condition present a band alignment favorable for photovoltaic conversion. Energy of adhesion, and charge transfer across the interfaces are also studied. The termination of CH$_3$NH$_3$PbI$_3$ in PbI$_2$ atomic planes seems optimal to maximize the photoconversion efficiency.Comment: 16 pages; 8 figures. Submitted to ACS Applied Materials & Interfaces. Published after changes not included her

Synthesis and H+, Cu2+, and Zn2+ Coordination Behavior of a Bis(fluorophoric) Bibrachial Lariat Aza-Crown

The synthesis, protonation behavior, and Cu2+ and Zn2+ coordination chemistry of the novel bibrachial aza lariat ether (naphthalen-1-ylmethyl)[2-(20-{2-[(naphthalen-1-ylmethyl)amino]ethyl}-3,6,9,17,20,23,29,30-octaazatricyclo[23.3.1.1*11,15*]triaconta-1(29),11(30),12,14,25,27-hexaen-6-yl)ethyl]amine (L) are discussed. The macrocycle, which has two aminoethyl naphthyl moieties symmetrically appended to a 2:2 azapyridinophane structure, displays, in the pH range 2−11, six protonation steps that correspond to the protonation of the secondary amino groups. Steady-state fluorescence measurements show emissions due to the monomer and to the excimer formed between the two naphthalene fragments of the macrocycle. The time-resolved fluorescence data, obtained by the time-correlated single photon counting technique, show that a significant percentage of excimer is preformed as ground-state dimers. The ligand L forms with the metal ions Cu2+ and Zn2+ mono- and dinuclear complexes in aqueous solution. The influence of metal coordination in the fluorescence emission of L is analyzed. The acid−base, coordination capabilities, and emissive behavior of L are compared with those presented by its synthetic precursor L1, which has a tripodal tris(2-aminoethyl)amine structure functionalized at one of its terminal amino groups with a naphthyl moiet