Comparing PVP and Polymeric Micellar Formulations of a PEGylated Photosensitizing Phthalocyanine by NMR and Optical Techniques.

Phthalocyanines are ideal candidates as photosensitizers for photodynamic therapy (PDT) of cancer due to their favorable chemical and photophysical properties. However, their tendency to form aggregates in water reduces PDT efficacy and poses challenges in obtaining efficient forms of phthalocyanines for therapeutic applications. In the current work, polyvinylpyrrolidone (PVP) and micellar formulations were compared for encapsulating and monomerizing a water-soluble zinc phthalocyanine bearing four non-peripheral triethylene glycol chains (Pc1). 1H NMR spectroscopy combined with UV-vis absorption and fluorescence spectroscopy revealed that Pc1 exists as a mixture of regioisomers in monomeric form in dimethyl sulfoxide but forms dimers in an aqueous buffer. PVP, polyethylene glycol castor oil (Kolliphor RH40), and three different triblock copolymers with varying proportions of polyethylene and polypropylene glycol units (termed P188, P84, and F127) were tested as micellar carriers for Pc1. 1H NMR chemical shift analysis, diffusion-ordered spectroscopy, and 2D nuclear Overhauser enhancement spectroscopy was applied to monitor the encapsulation and localization of Pc1 at the polymer interface. Kolliphor RH40 and F127 micelles exhibited the highest affinity for encapsulating Pc1 in the micellar core and resulted in intense Pc1 fluorescence emission as well as efficient singlet oxygen formation along with PVP. Among the triblock copolymers, efficiency in binding and dimer dissolution decreased in the order F127 > P84 > P188. PVP was a strong binder for Pc1. However, Pc1 molecules are rather surface-attached and exist as monomer and dimer mixtures. The results demonstrate that NMR combined with optical spectroscopy offer powerful tools to assess parameters like drug binding, localization sites, and dynamic properties that play key roles in achieving high host-guest compatibility. With the corresponding adjustments, polymeric micelles can offer simple and easily accessible drug delivery systems optimizing phthalocyanines' properties as efficient photosensitizers

Comparing PVP and Polymeric Micellar Formulations of a PEGylated Photosensitizing Phthalocyanine by NMR and Optical Techniques

Phthalocyanines are ideal candidates as photosensitizers for photodynamic therapy (PDT) of cancer due to their favorable chemical and photophysical properties. However, their tendency to form aggregates in water reduces PDT efficacy and poses challenges in obtaining efficient forms of phthalocyanines for therapeutic applications. In the current work, polyvinylpyrrolidone (PVP) and micellar formulations were compared for encapsulating and monomerizing a water-soluble zinc phthalocyanine bearing four non-peripheral triethylene glycol chains (Pc1). 1H NMR spectroscopy combined with UV–vis absorption and fluorescence spectroscopy revealed that Pc1 exists as a mixture of regioisomers in monomeric form in dimethyl sulfoxide but forms dimers in an aqueous buffer. PVP, polyethylene glycol castor oil (Kolliphor RH40), and three different triblock copolymers with varying proportions of polyethylene and polypropylene glycol units (termed P188, P84, and F127) were tested as micellar carriers for Pc1. 1H NMR chemical shift analysis, diffusion-ordered spectroscopy, and 2D nuclear Overhauser enhancement spectroscopy was applied to monitor the encapsulation and localization of Pc1 at the polymer interface. Kolliphor RH40 and F127 micelles exhibited the highest affinity for encapsulating Pc1 in the micellar core and resulted in intense Pc1 fluorescence emission as well as efficient singlet oxygen formation along with PVP. Among the triblock copolymers, efficiency in binding and dimer dissolution decreased in the order F127 > P84 > P188. PVP was a strong binder for Pc1. However, Pc1 molecules are rather surface-attached and exist as monomer and dimer mixtures. The results demonstrate that NMR combined with optical spectroscopy offer powerful tools to assess parameters like drug binding, localization sites, and dynamic properties that play key roles in achieving high host–guest compatibility. With the corresponding adjustments, polymeric micelles can offer simple and easily accessible drug delivery systems optimizing phthalocyanines’ properties as efficient photosensitizers

Science objective and status of the EnVision Mission to Venus

International audienceEnVision was selected in 2021 as ESA's fifth Medium-class mission to Venus, in partnership NASA, where NASA provides the Synthetic Aperture Radar instrument. The ESA mission adoption is scheduled for January 2024, and the launch for 2031. EnVision's scientific goal is to provide a holistic view of the planet, from its inner core to its upper atmosphere, studying the planet's history, activity, and climate. EnVision aims to establish the nature and current state of Venus' geological evolution and its relationship with the atmosphere. EnVision's overall science objectives are to: (i) characterize the sequence of events that formed the regional and global surface features of Venus, as well as the geodynamic framework that has controlled the release of internal heat over Venus history; (ii) determine how geologically active the planet is today; (iii) establish the interactions between the planet and its atmosphere at present and through time. Furthermore, EnVision will look for evidence of past liquid water on its surface. The nominal EnVision science phase of the mission will last about four Earth years. The science objectives will be addressed by its five instruments and one experiment, provided by European and US research institutes and space agencies. The VenSAR S-band radar will perform targeted surface imaging as well as polarimetric and stereo imaging, radiometry, and altimetry. The high-frequency Subsurface Radar Sounder (SRS) will sound the upper crust in search of material boundaries. Three spectrometers, VenSpec-U, VenSpec-H and VenSpec-M, operating in the UV and Near- and Short Wave-IR, respectively, will map trace gases, search for volcanic gas plumes above and below the clouds, and map surface emissivity and composition. A Radio Science Experiment (RSE) investigation will exploit the spacecraft Telemetry Tracking and Command (TT&C in Ka-/X bands) system to determine the planet's gravity field and to sound the structure and composition of the middle atmosphere and the cloud layer in radio occultation. All instruments have substantial heritage and robust requirement margins, with designs suitable for operation in the Venus environment. The EnVision science teams will adopt an open data policy, with public release of the scientific data after validation and verification. In this presentation, the scientific objectives and status of the EnVision Phase B1 activities will be presented, including an overview of ongoing work by the EnVision science team on the mission consolidation

Science objective and status of the EnVision Mission to Venus

International audienceEnVision was selected in 2021 as ESA's fifth Medium-class mission to Venus, in partnership NASA, where NASA provides the Synthetic Aperture Radar instrument. The ESA mission adoption is scheduled for January 2024, and the launch for 2031. EnVision's scientific goal is to provide a holistic view of the planet, from its inner core to its upper atmosphere, studying the planet's history, activity, and climate. EnVision aims to establish the nature and current state of Venus' geological evolution and its relationship with the atmosphere. EnVision's overall science objectives are to: (i) characterize the sequence of events that formed the regional and global surface features of Venus, as well as the geodynamic framework that has controlled the release of internal heat over Venus history; (ii) determine how geologically active the planet is today; (iii) establish the interactions between the planet and its atmosphere at present and through time. Furthermore, EnVision will look for evidence of past liquid water on its surface. The nominal EnVision science phase of the mission will last about four Earth years. The science objectives will be addressed by its five instruments and one experiment, provided by European and US research institutes and space agencies. The VenSAR S-band radar will perform targeted surface imaging as well as polarimetric and stereo imaging, radiometry, and altimetry. The high-frequency Subsurface Radar Sounder (SRS) will sound the upper crust in search of material boundaries. Three spectrometers, VenSpec-U, VenSpec-H and VenSpec-M, operating in the UV and Near- and Short Wave-IR, respectively, will map trace gases, search for volcanic gas plumes above and below the clouds, and map surface emissivity and composition. A Radio Science Experiment (RSE) investigation will exploit the spacecraft Telemetry Tracking and Command (TT&C in Ka-/X bands) system to determine the planet's gravity field and to sound the structure and composition of the middle atmosphere and the cloud layer in radio occultation. All instruments have substantial heritage and robust requirement margins, with designs suitable for operation in the Venus environment. The EnVision science teams will adopt an open data policy, with public release of the scientific data after validation and verification. In this presentation, the scientific objectives and status of the EnVision Phase B1 activities will be presented, including an overview of ongoing work by the EnVision science team on the mission consolidation