Latest ArticlesHighly branched poly(β-amino ester)s (HPAEs) have shown their great promise in gene delivery. However, their broad molecular weight distribution (MWD) poses an additional challenge to the mechanistic understanding of the influence of molecular weight (MW) on their gene transfection activity. Using a stepwise precipitation strategy, HPAEs were fractionated. It is shown that MW has a significant effect on the transfection activity and cytotoxicity of HPAEs. The intermediate MW mediates higher transfection efficiency while maintaining high cell viability. Mechanistic studies show that the intermediate MW confers stronger DNA binding affinity to HPAEs, leading to the formulation of polyplexes with a relatively smaller size and more positive zeta potential. This study not only suggests a simple strategy to fractionate HPAEs with narrow MWD but also provides new insights into understanding the structure-property relationship, which would facilitate the clinical translation of HPAEs in gene therapy.
The transdermal drug delivery (TDD) shows considerable advantages over other administration pathways. However, conventional enhancing permeation methods face a series of challenges owing to barrier function provided by the skin, of which enhancing abilities either are so strong that it results in toxicity and irritation, or too weak to achieve desirable therapeutical effects. To address these issues, it is an urgent need to develop a novel method to overcome the limitations of current measures. Fortunately, in the preceding decades, ionic liquids (ILs) have been extensively studied and increasingly applied in pharmaceutical drug delivery due to their unique physicochemical and biological properties. What is more, tunability of structure resolves the challenges in processing active pharmaceutical ingredient (API) formulation, such as polymorphism and poor solubility of drugs. Thus, the presence of ILs provides an ample design space for the transdermal drug delivery system (TDDS). This review discusses the shortcomings of conventional enhancing permeation methods and introduces the application of ILs in transdermal delivery from three aspects: ⅰ) ILs are applied as enhancers to weaken the barrier function of the stratum corneum (SC). ⅱ) As counterions, ILs are combined with API to modify the physicochemical properties of drugs. ⅲ) ILs assist in the design of transdermal preparation for perfecting formulation. This review comprehensively introduces the major breakthroughs made in the applications of ILs, which can serve as guidance to provide novel ideas for formulation scientists who hit the bottleneck in the development of TDD.
Here we use nor-seco-cucurbit[10]uril (ns-CB[10]) based ternary complexation to construct [5]rotaxane, linear supramolecular dynamic rotaxane polymers and cubic 3D supramolecular organic framework. A [5]rotaxane is constructed by ns-CB[10], TMeCB[6] and short linear derivatives of 4, 4′-bipyridinium (M2). ns-CB[10], CB[7] and long linear derivatives of 4, 4′-bipyridinium (M3) self-assemble into a linear supramolecular dynamic rotaxane polymer. ns-CB[10] and tetracationic tetrahedral monomer self-assemble and form a three-dimensional supramolecular organic framework. The above results demonstrate that ns-CB[10]-based ternary complexation is a versatile platform to build various supramolecular systems.
In this work, a liquid-gas heterogeneous microreactor was developed for investigating continuous crystallization of dolutegravir sodium (DTG), as well as revealing reaction kinetics and mixing mechanism with 3-min data acquisition. The reaction kinetics models were established by visually recording the concentration variation of reactants over time in the microchannel via adding pH-sensitive fluorescent dye. The mixing intensification mechanism of liquid-gas flow was quantified through the fluorescent signal to indicate mixing process, demonstrating an outstanding mixing performance with a mixing time less than 0.1 s. Compared with batch crystallization, continuous synthesis of dolutegravir sodium using liquid-gas heterogenous microreactor optimizes crystal distribution size, and successfully modifies the crystal morphology in needle-like habit instead of rod-like habit. The microreactor continuous crystallization can run for 5 h without crystal blockage and achieve D90 of DTG less than 30 µm. This work provides a feasible approach for continuously synthesizing dolutegravir sodium, and can optimize the existing pharmaceutical crystallization.
The development of out-of-equilibrium self-assembly systems using light as input fuel is highly desirable and promising for the fabrication of smart supramolecular materials. Herein, we report the construction of new artificial light-fueled dissipative molecular and macroscopic self-assembly systems based on a visible-light-responsive transient quadruple H-bonding array, which consists of an azobenzene-modified ureidopyrimidinone (UPy) module (Azo-O-UPy) and a nonphotoactive diamidonaphthyridine (DAN) derived competitive binder (Napy-1). The visible light (410 nm) irradiation can induce the E to Z isomerization of the azobenzene unit of E-Azo-O-UPy to produce Z-Azo-O-UPy with an opened UPy binding site, which can complex with Napy-1 to form a quadruply H-bonded heterodimer. The heterodimer is metastable and can be quickly disassembled in dark, owing to the fast thermal relaxation of Z-Azo-O-UPy to E-Azo-O-UPy. While introducing such transient quadruple H-bonding interaction into a linear polymer system or a polymeric gel system, light-fueled out-of-equilibrium polymeric assembly both at molecular and macro-scale can be achieved.
Three novel dithienylethenes modified by bifluoroboron β-diketonate fragments have been successfully developed. Upon blue light irradiation, they reached photostationary state within 2–5 s, as well as 100% conversion ratio and photocyclization quantum yield of > 0.70. Such fascinating photochromism were endowed by collaborative role of electron-withdrawing effect of BF2bdk group to reduce HOMO-LUMO electronic gap for the open isomer, together with intramolecular hydrogen bonds and CH-π interactions favoring antiparallel conformation fixation. Moreover, they displayed specific discrimination and photoswitchable bacterial imaging for S. aureus.
Catalytic asymmetric dearomatization of indoles and alkynes has received much attention in the past decade because this strategy offers an attractive and alternative way for the efficient synthesis of valuable chiral polycyclic indolines. However, these reactions have been mostly limited to transition-metal catalysts, and the related chiral Brønsted acid catalysis has been scarcely reported. Herein, we disclose a chiral phosphoric acid-catalyzed asymmetric dearomatization of indolyl ynamides by direct activation of alkynes. This metal-free method enables the practical and atom-economical construction of an array of valuable chiral polycyclic indolines in moderate to good yields with high enantioselectivities
Corneal neovascularization (CNV) is one of the major factors for vision impairment and blindness worldwide. The current treatment for CNV focuses primarily on topical eyedrops of glucocorticoids, non-steroidal anti-inflammatory drugs, electro-coagulation and laser photo-coagulation. Unfortunately, coagulation-based treatment is restricted by corneal hemorrhage and iris atrophy. And drug treatments have limited therapeutic effects and a short duration of action. Nanoparticle-based drug delivery systems are widely applied due to their improved pharmacokinetics, optimized drug targeting and enhanced biocompatibility. In this article, we provide a comprehensive and systematic overview of the CNV nanodrug system, highlighting some of the recent advances in nanodrug design, preparation, and functional modification. Moreover, we discuss the challenges in the clinical translation and potential risks in CNV treatment. A greater effort is needed for the potential applications of nanotechnology in the field of ophthalmology.
It is of great significance to construct organic circularly polarized luminescence systems (CPL) with large luminescence dissymmetry factors (glum) for practical applications. Here we report organic CPL systems constructed by merging triplet-triplet annihilation upconversion chromophores in cellulose matrices. The chirality of the matrix is transferred to the achiral chromophores of photon upconversion and then the multistep energy transfer processes of upconversion amplify glum. The glum value of upconversion CPL in the left-handed ethyl cellulose and the right-handed (acetyl) ethyl cellulose are up to +0.1 and −0.15, respectively. The study provides a straightforward approach for constructing solid organic upconversion CPL materials with large glum, which may expand the application potentials of organic chiroptical materials.
In recent years, nanozymes have received more and more attention, but the low activity limits the development of nanozymes. Therefore, the design and development of efficient nanozymes is still a major challenge for researchers. Herein, the Fe,N co-doped ultrathin hollow carbon framework (Fe,N-UHCF) exhibit ultra-high peroxidase-like activity. The specific activity of Fe,N-UHCF nanozyme is as high as 36.6 U/mg, which is much higher than almost all of other reported nanozymes. In practical applications, the Fe,N-UHCF show good antibacterial effects.
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