Challenges in nanoscale characterization call for non-invasive, yet sensitive subsurface characterization of low-density materials such as polymers. In this work, we present new evidence that mode-synthesizing atomic ...Challenges in nanoscale characterization call for non-invasive, yet sensitive subsurface characterization of low-density materials such as polymers. In this work, we present new evidence that mode-synthesizing atomic force microscopy can be used to detect minute changes in low-density materials, such as those engendered in electro-sensitive polymers during electron beam lithography, surpassing all common nanoscale mechanical techniques. Moreover, we propose 3D reconstruction of the exposed polymer regions using successive high-resolution frames acquired at incremental depths inside the sample. In addition, the results clearly show the influence of increasing dwell time on the depth profile of the nano-sized exposed regions. Hence, the simple approach described here can be used for achieving sensitive nanoscale tomography of soft materials with promising applications in material sciences and biology.展开更多
Synaptic vesicles can undergo several modes of exocytosis,endocytosis,and trafficking within individual synapses,and their fates may be linked to different vesicular protein compositions.Here,we mapped the intrasynapt...Synaptic vesicles can undergo several modes of exocytosis,endocytosis,and trafficking within individual synapses,and their fates may be linked to different vesicular protein compositions.Here,we mapped the intrasynaptic distribution of the synaptic vesicle proteins SV2B and SV2A in glutamatergic synapses of the hippocampus using three-dimensional electron microscopy.SV2B was almost completely absent from docked vesicles and a distinct cluster of vesicles found near the active zone.In contrast,SV2A was found in all domains of the synapse and was slightly enriched near the active zone.SV2B and SV2A were found on the membrane in the peri-active zone,suggesting the recycling from both clusters of vesicles.SV2B knockout mice displayed an increased seizure induction threshold only in a model employing high-frequency stimulation.Our data show that glutamatergic synapses generate molecularly distinct populations of synaptic vesicles and are able to maintain them at steep spatial gradients.The almost complete absence of SV2B from vesicles at the active zone of wildtype mice may explain why SV2A has been found more important for vesicle release.展开更多
文摘Challenges in nanoscale characterization call for non-invasive, yet sensitive subsurface characterization of low-density materials such as polymers. In this work, we present new evidence that mode-synthesizing atomic force microscopy can be used to detect minute changes in low-density materials, such as those engendered in electro-sensitive polymers during electron beam lithography, surpassing all common nanoscale mechanical techniques. Moreover, we propose 3D reconstruction of the exposed polymer regions using successive high-resolution frames acquired at incremental depths inside the sample. In addition, the results clearly show the influence of increasing dwell time on the depth profile of the nano-sized exposed regions. Hence, the simple approach described here can be used for achieving sensitive nanoscale tomography of soft materials with promising applications in material sciences and biology.
基金supported by grants from Deutsche Forschungsgemeinschaft(DFG)(SFB1089,SCHO 820/4-1,SCHO 820/6-1,SCHO 820/7-1,SCHO 820/5-2,and SPP1757 to S.S.,SFB1089,SPP1757,INST117215,DI853/3-5&7,and INST 217/785-1 to D.D.),the BONFOR program of the University of Bonn Medical Center(S.S.and D.D.),and UCB Pharma.
文摘Synaptic vesicles can undergo several modes of exocytosis,endocytosis,and trafficking within individual synapses,and their fates may be linked to different vesicular protein compositions.Here,we mapped the intrasynaptic distribution of the synaptic vesicle proteins SV2B and SV2A in glutamatergic synapses of the hippocampus using three-dimensional electron microscopy.SV2B was almost completely absent from docked vesicles and a distinct cluster of vesicles found near the active zone.In contrast,SV2A was found in all domains of the synapse and was slightly enriched near the active zone.SV2B and SV2A were found on the membrane in the peri-active zone,suggesting the recycling from both clusters of vesicles.SV2B knockout mice displayed an increased seizure induction threshold only in a model employing high-frequency stimulation.Our data show that glutamatergic synapses generate molecularly distinct populations of synaptic vesicles and are able to maintain them at steep spatial gradients.The almost complete absence of SV2B from vesicles at the active zone of wildtype mice may explain why SV2A has been found more important for vesicle release.
