MDGAs are fast-diffusing molecules that delay excitatory synapse development by altering neuroligin behavior

MDGAs are molecules that can bind neuroligins in cis and interfere with trans-synaptic neurexin-neuroligin interactions, thereby impairing synapse development. However, the sub-cellular localization and dynamics of MDGAs, as well as their specific mode of action in neurons are still unclear. Here, using both surface immunostaining of endogenous MDGAs and single molecule tracking of recombinant MDGAs in dissociated hippocampal neurons, we show that MDGA1 and MDGA2 molecules are homogeneously distributed and exhibit fast membrane diffusion, with a small reduction in mobility across neuronal maturation in culture Using shRNAs and CRISPR/Cas9 strategies to knock-down/out MDGA1 or MDGA2, we demonstrate an increase in the density of excitatory synapses accompanied by enhanced membrane immobilization and an increase in the phosphotyrosine level of neuroligins associated with excitatory post-synaptic differentiation. Finally, we show that decreasing MDGA expression level reduces the mobility of AMPA receptors and increases the frequency of AMPA receptor mediated mEPSCs. Overall, our results support a mechanism by which interactions between MDGAs and neuroligin-1 delays the assembly of functional excitatory synapses containing AMPA receptors.

Silver Nanomaterials for Wound Dressing Applications

Silver nanoparticles (AgNPs) have recently become very attractive for the scientific community due to their broad spectrum of applications in the biomedical field. The main advantages of AgNPs include a simple method of synthesis, a simple way to change their morphology and high surface area to volume ratio. Much research has been carried out over the years to evaluate their possible effectivity against microbial organisms. The most important factors which influence the effectivity of AgNPs against microorganisms are the method of their preparation and the type of application. When incorporated into fabric wound dressings and other textiles, AgNPs have shown significant antibacterial activity against both Gram-positive and Gram-negative bacteria and inhibited biofilm formation. In this review, the different routes of synthesizing AgNPs with controlled size and geometry including chemical, green, irradiation and thermal synthesis, as well as the different types of application of AgNPs for wound dressings such as membrane immobilization, topical application, preparation of nanofibers and hydrogels, and the mechanism behind their antimicrobial activity, have been discussed elaborately.

An insertion/self-fusion mechanism for cell membrane immobilization on porous silica beads to fabricate biomimic carriers

An insertion/self-fusion mechanism for cell membrane immobilization on porous silica beads has been proposed to fabricate biomimic carriers.