Room to swing a cat: A chiral disulfonimide has been designed as a powerful new motif for asymmetric catalysis. As a first illustration, a highly efficient and enantioselective Mukaiyama aldol ...reaction has been developed (see scheme). The actual catalyst is proposed to be an N-silyl imide which is generated in situ.
Diagnostics have proven to be crucial to the COVID-19 pandemic response. There are three major methods for the detection of SARS-CoV-2 infection and their role has evolved during the course of the ...pandemic. Molecular tests such as PCR are highly sensitive and specific at detecting viral RNA, and are recommended by WHO for confirming diagnosis in individuals who are symptomatic and for activating public health measures. Antigen rapid detection tests detect viral proteins and, although they are less sensitive than molecular tests, have the advantages of being easier to do, giving a faster time to result, of being lower cost, and able to detect infection in those who are most likely to be at risk of transmitting the virus to others. Antigen rapid detection tests can be used as a public health tool for screening individuals at enhanced risk of infection, to protect people who are clinically vulnerable, to ensure safe travel and the resumption of schooling and social activities, and to enable economic recovery. With vaccine roll-out, antibody tests (which detect the host's response to infection or vaccination) can be useful surveillance tools to inform public policy, but should not be used to provide proof of immunity, as the correlates of protection remain unclear. All three types of COVID-19 test continue to have a crucial role in the transition from pandemic response to pandemic control.
Readily available o′-alkenyl-o-alkynylbiaryls, a particular type of 1,7-enynes, undergo a selective cycloisomerization reaction in the presence of a gold(I) catalyst to give interesting phenanthrene ...and dihydrophenanthrene derivatives in high yields. The solvent used provokes a switch in the evolution of the gold intermediate and plays a key role in the reaction outcome.
Acetaldehyde, now a big contender: A silyl prolinol derivative was found to catalyze the first Michael addition of acetaldehyde with both aromatic and aliphatic nitroolefins in excellent ...enantioselectivities (see scheme, TMS=trimethylsilyl). The utility of the reaction is illustrated in the synthesis of three current pharmaceuticals and in the synthesis of an enantiopure 3‐monosubstituted pyrrolidine.
Osteoclasts are the cells responsible for the bone resorption process during bone remodeling. In a healthy situation, this process results from an equilibrium between new matrix formation by ...osteoblast and matrix resorption by osteoclast. Osteoporosis (OP) is a systemic bone disease characterized by a decreased bone mass density and alterations in bone microarchitecture, increasing fracture predisposition. Despite the variety of available therapies for OP management there is a growing gap in its treatment associated to the low patients' adherence owing to concerns related with long‐term efficacy or safety. This makes the development of new and safe treatments necessary. Among the newly developed strategies, the use of synthetic and natural nanoparticles to modulate osteoclasts differentiation, activity, apoptosis or crosstalk with osteoblasts have arisen. Synthetic nanoparticles exert their therapeutic effect either by loading antiresorptive drugs or including molecules for osteoclasts gene regulation. Moreover, this control over osteoclasts can be improved by their targeting to bone extracellular matrix or osteoclast membranes. Furthermore, natural nanoparticles, also known as extracellular vesicles, have been identified to play a key role in bone homeostasis. Consequently, these systems have been widely studied to control osteoblasts and osteoclasts under variable environments. Additionally, the ability to bioengineer extracellular vesicles has allowed to obtain biomimetic systems with desirable characteristics as drug carriers for osteoclasts. The analyzed information reveals the possibility of modulating osteoclasts by different mechanisms through nanoparticles decreasing bone resorption. These findings suggest that controlling osteoclast activity using nanoparticles has the potential to improve osteoporosis management.
This article is categorized under:
Implantable Materials and Surgical Technologies > Nanomaterials and Implants
Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement
Nanotechnology Approaches to Biology > Nanoscale Systems in Biology
Natural and synthetic nanoparticles showed efficiency in modulating osteoclasts differentiation, activity, apoptosis and crosstalk with osteoblasts, thus leading to an attenuation in bone resorption, improved bone density and increased bone formation in osteoporosis. Therefore, nanoparticles for osteoclasts control are suitable systems in OP management.
A general method for the functionalization of 4a‐aza‐8a‐boranaphthalene in the position β to the nitrogen atom has been developed. This method is based on a regioselective iridium‐catalyzed C−H ...activation process for the introduction of a boronate group, which can subsequently be transformed into a variety of aryl or alkynyl groups via cross‐coupling reactions. Selective mono‐ or difunctionalization can be achieved by controlling the reaction conditions during the borylation step. The photophysical properties of the obtained 3‐ or 3,6‐substituted BN‐naphthalenes have been evaluated, and some of them have been found to be significantly fluorescent, with fluorescence quantum yields up to 0.85.
The total synthesis of Laetevirenol A, a natural product with antioxidant activity, has been achieved. A gold‐catalyzed cycloisomerization of an o‐alkenyl‐o’‐alkynylbiphenyl has been used as the key ...step for the construction of the phenanthrene moiety present in Laetevirenol A. Several studies in model substrates have been carried out to unveil the effect of substituents in different locations in the outcome of this cyclization, which allowed the design of an appropriate precursor for the fundamental gold‐catalyzed cycloisomerization. The suitably functionalized phenanthrene intermediate obtained in this key step could be further transformed into Laetevirenol A via a Friedel‐Crafts cyclization, which also turned out to be dependent on the nature of the substituents. Finally, Laetevirenol A was obtained in 10 steps from commercially available substrates, with a 20% global yield.
Previously unknown 1,2-dihydro-1-aza-2-boraphenanthrene has been synthesized in only three steps from 2-bromo-1-vinylnaphthalene. The reactivity of this new BN-phenanthrene, and of several ...substituted derivatives, has been tested against bromine and organolithium compounds. Bromination proceeded with complete regioselectivity, affording bromo-substituted compounds suitable for further functionalization via cross-coupling reactions. This new family of BN-phenanthrenes exhibits a substantial increase in the quantum yield (up to ϕF = 0.93) with respect to phenanthrene.
Display omitted
•LPHNPs exhibiting suitable properties were obtained by both bulk and microfluidics.•LPHNPs were surface-tuned with an aptamer/antibody using an optimized protocol.•Microfluidics ...enables a more precise control over critical formulation parameters.
Lipid-polymer hybrid nanoparticles are promising platforms in the field of targeted drug delivery, integrating the positive features of polymeric and lipid nanocarriers. However, the use of bulk procedures in lipid-polymer hybrid nanoparticles formulation is hindering their large-scale manufacturing. Therefore, the aim of this study is to explore the suitability of alternative formulation methods, such as microfluidics, to obtain surface-tunable nanoparticles displaying suitable characteristics. Formulations were prepared by single-step nanoprecipitation or using a micromixer chip. The nanocarriers were then surface-modified with an aptamer and an antibody, two common nanoparticle vectorization strategies, developing an optimized functionalization protocol. Both naked and surface-modified nanoparticles were characterized in terms of size, polydispersity, zeta potential and morphology. Moreover, the aptamer/antibody association efficiency was also determined. Nano-sized monodisperse nanoparticles, exhibiting a spherical core–shell structure, were obtained through both procedures. Furthermore, all the nanocarriers were successfully functionalized, showing association efficiency values above 70%. Interestingly, microfluidic-based nanoparticles displayed a smaller size and a more positive zeta potential than those prepared by single-step nanoprecipitation. Outcomes suggest both techniques led to lipid-polymer hybrid nanoparticles displaying a similar functionalization efficiency. Conversely, the microfluidic approach provided an improved control over critical parameters, as particle size or charge, constituting an interesting alternative to traditional formulation procedures.
PDF
