Click Chemistry for Drug Delivery Nanosystems

This is a post-peer-review, pre-copyedit version of an article published in Pharmaceutical Research. The final authenticated version is available online at: https://doi.org/10.1007/s11095-011-0568-5The purpose of this Expert Review is to discuss the impact of click chemistry in nanosized drug delivery systems. Since the introduction of the click concept by Sharpless and coworkers in 2001, numerous examples of click reactions have been reported for the preparation and functionalization of polymeric micelles and nanoparticles, liposomes and polymersomes, capsules, microspheres, metal and silica nanoparticles, carbon nanotubes and fullerenes, or bionanoparticles. Among these click processes, Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) has attracted most attention based on its high orthogonality, reliability, and experimental simplicity for non-specialists. A renewed interest in the use of efficient classical transformations has been also observed (e.g., thiol-ene coupling, Michael addition, Diels-Alder). Special emphasis is also devoted to critically discuss the click concept, as well as practical aspects of application of CuAAC to ensure efficient and harmless bioconjugationThis work was financially supported by the Spanish Ministry of Science and Innovation (CTQ2009-10963 and CTQ2009-14146-C02-02) and the Xunta de Galicia (10CSA209021PR)S

Medida óptica de pulsos generados mediante encadenado de modos.

Las dos técnicas más habituales utilizadas para generar pulsos de luz láser son el Q-switching y el Mode-Locking. El Q-switching permite obtener pulsos en torno al nanosegundo, mientras que con el método Mode-Locking (también conocido como encadenado de modos o bloqueo de fase) se pueden alcanzar duraciones del orden del picosegundo o, incluso, de algunos femtosegundos. Las propiedades más relevantes de los pulsos generados son: la energía emitida por pulso, su duración, su forma y la cadencia de los mismos (frecuencia de repetición de los pulsos). Además, conocidas la duración y energía del pulso, podemos determinar su potencia y, con determinadas técnicas, ajustarla para una finalidad concreta. La necesidad de medir la duración real de estos pulsos supone todo un reto ya que, en la actualidad, los dispositivos electrónicos solo permiten medir eventos de duraciones por encima de los 50 ps, resultando, en todo caso, complicado y costoso llegar a estos valores [3][4]. Por ello, es necesaria una alternativa. Ésta, se presenta como un procedimiento de carácter esencialmente óptico en el cual se realiza la comparación del pulso que queremos caracterizar con un patrón de la misma magnitud. Así pues, la finalidad de este trabajo es el estudio y caracterización de una técnica de medida de pulsos muy cortos. Concretamente, las autocorrelaciones de primer y segundo orden, utilizando un interferómetro tipo Michelson y un cristal BBO doblador de frecuencia. Vamos a realizar la medida de pulsos para varias configuraciones distintas introduciendo tramos de fibra de dispersión positiva y de dispersión negativa en diferentes etapas del montaje [4]. Esencialmente, se puede introducir fibra en tres etapas del montaje de medida: Etapa 1: en el interior de la cavidad de anillo. Etapa 2: entre el láser de anillo y el EDFA L. Etapa 3: entre el interferómetro Michelson y el sistema BBO. Esto se realiza con la intención de compensar parcial o totalmente la dispersión producida en cada una de ellas, incluida la cavidad de anillo cuya dispersión es no nula. Aunque inicialmente parecía que el montaje para la medida de pulsos generados mediante Mode-Locking no presentaría mayores complicaciones, hemos visto que requiere de mucha práctica y que es necesario un conocimiento sólido de los distintos dispositivos, así como de los principios físicos en los que se basa. A pesar de ello, se ha conseguido finalizar el sistema medidor de pulsos y realizar numerosas pruebas que confirman su correcto funcionamiento para la obtención de los interferogramas que nos permiten inferir la duración de los pulsos. De hecho, hemos conseguido determinar la duración que tendrían los pulsos, generados por Mode-Locking, si no tuvieran dispersión. Este dato es importante, ya que nos da una idea de cuál es la duración mínima que pueden tener los pulsos generados con esta técnica

Crossbow injuries: a case of suicide

6 p.We are reporting the case of a 65 year-old man who suffered a severe depression and committed suicide using a crossbow. The death happened at his home. The suicide victim was on his knees, with of a crossbow leveled at his thorax and located facing him on the sofa. He shot it by pulling the trigger with the bended end of a ramrod. The arrow entered between the third and the fourth rib on the left side, with a downwards and slightly outwards direction. It went through the lung and the tip of the arrow came out the back. The arrow was removed when the body was lifted, and the wounds had a three-pointed star shape which corresponded to the head of the arrow crossbow. Police enquiry and forensic investigation confirmed a suicidal manner of death. This paper presents different issues of the case, such as the attestation of tears in clothing, the morphology of the wounds or the arrow track. The case is compared with other cases in the medical forensic literature involving the use of crossbows. Finally, it is highlighted how easy it is to purchase these weapons despite their obvious power and accuracy, factors that seriously recommend legislative regulation to be increased and its use more restricted

Binding and Internalization in Receptor‐Targeted Carriers: The Complex Role of CD44 in the Uptake of Hyaluronic Acid‐Based Nanoparticles (siRNA Delivery)

This paper is about the actual role of CD44 in the perspective of a hyaluronic acid (HA)-based, targeted therapy. CD44 is the main HA receptor: it is present both in healthy and cancerous cells, but is overexpressed in many carcinomas, with important roles in their initiation and malignancy. This, and its endocytic capacities, have encouraged the use of HA to design CD44-targeting carriers. Here, we have used HA-decorated nanoparticles to deliver a siRNA payload to a panel of human cells comprising both tumoral (AsPC-1, PANC-1, HT-29, HCT-116) and non-tumoral (fibroblasts, differently polarized THP-1 macrophages, HUVEC) lines; we have evaluated in a comparative and quantitative fashion the initial binding of the nanoparticles, their internalization rate and the eventual silencing efficiency (cyclophilin B (PPIB) gene).A first result of our study is that, in general, tumoral cells internalized faster and experienced higher silencing than non-tumoral cells. This result is promising as it suggests that, when in a tumor environment, HA nanocarriers may have limited off-target effects.A more far-reaching result comes from the quantitative analysis of the inter-relation between the four parameters of our study (i.e. total CD44 expression, extent of HA cell surface binding, internalization rate and silencing efficiency). Our experiments showed no correlation between extent of binding (an early event) and any of the other parameters. On the contrary, silencing correlated well both with the speed of the internalization process and also with CD44 expression. This study, therefore, confirms on one hand that HA-based carriers can perform a targeted therapeutic action, but on the other it suggests that this may not be due to the selective binding of a cell surface marker, but possibly to a later recognition event leading to selective internalization

Fiber-Optic Pyrometer with Optically Powered Switch for Temperature Mesurements

We report the experimental results on a new infrared fiber-optic pyrometer for very localized and high-speed temperature measurements ranging from 170 to 530 degrees C using low-noise photodetectors and high-gain transimpedance amplifiers with a single gain mode in the whole temperature range. We also report a shutter based on an optical fiber switch which is optically powered to provide a reference signal in an optical fiber pyrometer measuring from 200 to 550 degrees C. The tests show the potential of remotely powering via optical means a 300 mW power-hungry optical switch at a distance of 100 m, avoiding any electromagnetic interference close to the measuring point.This work was supported by the Spanish Ministry of Economy and Competitiveness and FEDER program under grants TEC2015-63826-C3-2-R and by Comunidad de Madrid under grant S2013/MIT-2790

Chemical specificity in REDOX-responsive materials:the diverse effects of different Reactive Oxygen Species (ROS) on polysulfide nanoparticles

REDOX responsive (nano)materials typically exhibit chemical changes in response to the presence and concentration of oxidants/reductants. Due to the complexity of biological environments, it is critical to ascertain whether the chemical response may depend on the chemical details of the stimulus, in addition to its REDOX potential, and whether chemically different responses can determine a different overall performance of the material. Here, we have used oxidation-sensitive materials, although these considerations can be extended also to reducible ones. In particular, we have used poly(propylene sulfide) (PPS) nanoparticles coated with a PEGylated emulsifier (Pluronic F127); inter alia, we here present also an improved preparative method. The nanoparticles were exposed to two Reactive Oxygen Species (ROS) typically encountered in inflammatory reactions, hydrogen peroxide (H2O2) and hypochlorite (ClO−); their response was evaluated with a variety of techniques, including diffusion NMR spectroscopy that allowed to separately characterize the chemically different colloidal species produced. The two oxidants triggered a different chemical response: H2O2 converted sulfides to sulfoxides, while ClO− partially oxidized them further to sulfones. The different chemistry correlated to a different material response: H2O2 increased the polarity of the nanoparticles, causing them to swell in water and to release the surface PEGylated emulsifier; the uncoated oxidized particles still exhibited very low toxicity. On the contrary, ClO− rapidly converted the nanoparticles into water-soluble, depolymerized fragments with a significantly higher toxicity. The take-home message is that it is more correct to discuss ‘smart’ materials in terms of an environmentally specific response to (REDOX) stimuli. Far from being a problem, this could open the way to more sophisticated and precisely targeted applications

Microfluidic-assisted preparation of RGD-decorated nanoparticles: exploring integrin-facilitated uptake in cancer cell lines

From Springer Nature via Jisc Publications RouterHistory: received 2020-02-23, accepted 2020-08-06, registration 2020-08-17, pub-electronic 2020-09-02, online 2020-09-02, collection 2020-12Publication status: PublishedFunder: AstraZeneca; doi: http://dx.doi.org/10.13039/100004325Funder: University of Manchester; doi: http://dx.doi.org/10.13039/501100000770Abstract: This study is about fine tuning the targeting capacity of peptide-decorated nanoparticles to discriminate between cells that express different integrin make-ups. Using microfluidic-assisted nanoprecipitation, we have prepared poly(lactic acid-co-glycolic acid) (PLGA) nanoparticles with a PEGylated surface decorated with two different arginine-glycine-aspartic acid (RGD) peptides: one is cyclic (RGDFC) and has specific affinity towards αvβ3 integrin heterodimers; the other is linear (RGDSP) and is reported to bind equally αvβ3 and α5β1. We have then evaluated the nanoparticle internalization in two cell lines with a markedly different integrin fingerprint: ovarian carcinoma A2780 (almost no αvβ3, moderate in α5β1) and glioma U87MG (very high in αvβ3, moderate/high in α5β1). As expected, particles with cyclic RGD were heavily internalized by U87MG (proportional to the peptide content and abrogated by anti-αvβ3) but not by A2780 (same as PEGylated particles). The linear peptide, on the other hand, did not differentiate between the cell lines, and the uptake increase vs. control particles was never higher than 50%, indicating a possible low and unselective affinity for various integrins. The strong preference of U87MG for cyclic (vs. linear) peptide-decorated nanoparticles was shown in 2D culture and further demonstrated in spheroids. Our results demonstrate that targeting specific integrin make-ups is possible and may open the way to more precise treatment, but more efforts need to be devoted to a better understanding of the relation between RGD structure and their integrin-binding capacity

Microfluidic-assisted preparation of RGD-decorated nanoparticles: exploring integrin-facilitated uptake in cancer cell lines.

Funder: AstraZeneca; doi: http://dx.doi.org/10.13039/100004325Funder: University of Manchester; doi: http://dx.doi.org/10.13039/501100000770This study is about fine tuning the targeting capacity of peptide-decorated nanoparticles to discriminate between cells that express different integrin make-ups. Using microfluidic-assisted nanoprecipitation, we have prepared poly(lactic acid-co-glycolic acid) (PLGA) nanoparticles with a PEGylated surface decorated with two different arginine-glycine-aspartic acid (RGD) peptides: one is cyclic (RGDFC) and has specific affinity towards αvβ3 integrin heterodimers; the other is linear (RGDSP) and is reported to bind equally αvβ3 and α5β1. We have then evaluated the nanoparticle internalization in two cell lines with a markedly different integrin fingerprint: ovarian carcinoma A2780 (almost no αvβ3, moderate in α5β1) and glioma U87MG (very high in αvβ3, moderate/high in α5β1). As expected, particles with cyclic RGD were heavily internalized by U87MG (proportional to the peptide content and abrogated by anti-αvβ3) but not by A2780 (same as PEGylated particles). The linear peptide, on the other hand, did not differentiate between the cell lines, and the uptake increase vs. control particles was never higher than 50%, indicating a possible low and unselective affinity for various integrins. The strong preference of U87MG for cyclic (vs. linear) peptide-decorated nanoparticles was shown in 2D culture and further demonstrated in spheroids. Our results demonstrate that targeting specific integrin make-ups is possible and may open the way to more precise treatment, but more efforts need to be devoted to a better understanding of the relation between RGD structure and their integrin-binding capacity

Rapid and sustained B-cell depletion with subcutaneous ofatumumab in relapsing multiple sclerosis : APLIOS, a randomized phase-2 study

Background: Ofatumumab, the first fully human anti-CD20 monoclonal antibody, is approved in several countries for relapsing multiple sclerosis (RMS). Objective: To demonstrate the bioequivalence of ofatumumab administered by an autoinjector versus a pre-filled syringe (PFS) and to explore the effect of ofatumumab on B-cell depletion. Methods: APLIOS (NCT03560739) is a 12-week, open-label, parallel-group, phase-2 study in patients with RMS receiving subcutaneous ofatumumab 20 mg every 4 weeks (q4w) (from Week 4, after initial doses on Days 1, 7, and 14). Patients were randomized 10:10:1:1 to autoinjector or PFS in the abdomen, or autoinjector or PFS in the thigh, respectively. Bioequivalence was determined by area under the curve (AUCτ) and maximum plasma concentration (Cmax) for Weeks 8-12. B-cell depletion and safety/tolerability were assessed. Results: A total of 256 patients contributed to the bioequivalence analyses (autoinjector-abdomen, n = 128; PFS-abdomen, n = 128). Abdominal ofatumumab pharmacokinetic exposure was bioequivalent for autoinjector and PFS (geometric mean AUCτ, 487.7 vs 474.1 h × µg/mL (ratio 1.03); Cmax, 1.409 vs 1.409 µg/mL (ratio 1.00)). B-cell counts (median cells/µL) depleted rapidly in all groups from 214.0 (baseline) to 2.0 (Day 14). Ofatumumab was well tolerated. Conclusion: Ofatumumab 20 mg q4w self-administered subcutaneously via autoinjector is bioequivalent to PFS administration and provides rapid B-cell depletion