Dendrimer-based Nanoparticle for Dye Sensitized Solar Cells with Improved Efficiency

Recent progress in nanomedicines for imaging and therapy of brain tumors

Nowadays, a malignant brain tumor is one of the most life-threatening diseases with poor prognosis, high risk of recurrence, and low survival rate for patients because of the existence of the blood-brain barrier (BBB) and the lack of efficient diagnostic and therapeutic paradigms. So far, many researchers have devoted their efforts to innovating advanced drugs to efficiently cross the BBB and selectively target brain tumors for optimal imaging and therapy outcomes. Herein, we update the most recent developments in nanomedicines for the diagnosis and treatment of brain tumors in preclinical mouse models. The special focus is on burgeoning drug delivery carriers to improve the specificity of visualization and to enhance the efficacy of brain tumor treatment. Also, we highlight the challenges and perspectives for the future development of brain tumor theranostics. This review is expected to receive wide attention from researchers, professors, and students in various fields to participate in future advancements in preclinical research and clinical translation of brain tumor nanomedicines.

Properties and Bioapplications of Amphiphilic Janus Dendrimers: A Review

Amphiphilic Janus dendrimers are arrangements containing both hydrophilic and hydrophobic units, capable of forming ordered aggregates by intermolecular noncovalent interactions between the dendrimer units. Compared to conventional dendrimers, these molecular self-assemblies possess particular and effective attributes i.e., the presence of different terminal groups, essential to design new elaborated materials. The present review will focus on the pharmaceutical and biomedical application of amphiphilic Janus dendrimers. Important information for the development of novel optimized pharmaceutical formulations, such as structural classification, synthetic pathways, properties and applications, will offer the complete characterization of this type of Janus dendrimers. This work will constitute an up-to-date background for dendrimer specialists involved in designing amphiphilic Janus dendrimer-based nanomaterials for future innovations in this promising field.

Preparation of New Glycerol-Based Dendrimers and Studies on Their Behavior toward Essential Oil Encapsulation

Two new families of glycerol-based dendrimers (glyceroladendrimers (GADs) and glyceroclickdendrimers (GCDs)) have been synthesized. Three generations have been isolated for each family with good yields and were fully analyzed. The encapsulation of essential oils (citronella and cinnamon) in GADs, GCDs, and also in previously described glycerodendrimers GD-PAMAMs and GD-PPIs has been studied by dynamic-headspace gas chromatography coupled to mass spectrometry. The retention rates obtained were from -35.8 to 26.65% for citronella essential oil and from 2.14 to 38.84% for the cinnamon essential oil. In addition, the best results were obtained with GD-PAMAMs and GD-PPIs of higher generation. The interaction study between essential oils or more precisely their major components have been performed through NMR spectroscopy (¹H NMR and DOSY NMR). No direct interactions between dendrimers and essential oils have been observed, but a surprising behavior of compression of the dendrimer in stable emulsions was observed. Indeed, the hydrodynamic radius of GD-PPI-3 has been reduced in the presence of cinnamon essential oil.

Photophysical Studies of Ruthenium-Based Complexes and the Performance of Nanostructured TiO2 Based Dye Sensitized Solar Cells

Dye-sensitized solar cells (DSSCs) have attracted enormous attention in the last couple of decades due to their relatively small size, low cost and minimal environmental impact. DSSCs convert solar energy to electrical energy with the aid of a sensitizing dye. In this work, two ruthenium-based dyes, tris(bipyridine)ruthenium(II) chloride (Rubpy) and ruthenium(II)2,2'-bis(benzimidazol-2-yl)-4,4'-bipyridine (RubbbpyH2), were synthesized, characterized, and investigated for use as dye sensitizers in the fabrication of DSSCs. The photovoltaic performance of the ruthenium-based DSSCs was assessed. The solar-to-electric power efficiency of the RubbbpyH2 DSSC was 0.2% and that of the Rubpy was 0.03%. The RubbbpyH2 was also deprotonated and analyzed to study the effect of deprotonation on the efficiency of the solar cell. The deprotonated species, Rubbbpy, recorded an average efficiency of 0.12%. Thus, a change in pH did not enhance the efficiency of the solar cell. The cells were further characterized by impedance measurements. The photocurrent-photovoltage results were not consistent with the absorption spectra since Rubbbpy showed a more prominent band than RubbbpyH2 but had a lower efficiency.