Robot-Embodied Neuronal Networks as an Interactive Model of Learning.

Background And Objective: The reductionist approach of neuronal cell culture has been useful for analyses of synaptic signaling. Murine cortical neurons in culture spontaneously form an network capable of transmitting complex signals, and have been useful for analyses of several fundamental aspects of neuronal development hitherto difficult to clarify . However, these networks lack the ability to receive and respond to sensory input from the environment as do neurons .

Synaptic signal streams generated by ex vivo neuronal networks contain non-random, complex patterns.

Cultured embryonic neurons develop functional networks that transmit synaptic signals over multiple sequentially connected neurons as revealed by multi-electrode arrays (MEAs) embedded within the culture dish. Signal streams of ex vivo networks contain spikes and bursts of varying amplitude and duration. Despite the random interactions inherent in dissociated cultures, neurons are capable of establishing functional ex vivo networks that transmit signals among synaptically connected neurons, undergo developmental maturation, and respond to exogenous stimulation by alterations in signal patterns.

Transient epileptiform signaling during neuronal network development: regulation by external stimulation and bimodal GABAergic activity.

A predominance of excitatory activity, with protracted appearance of inhibitory activity, accompanies cortical neuronal development. It is unclear whether or not inhibitory neuronal activity is solicited exclusively by excitatory neurons or whether the transient excitatory activity displayed by developing GABAergic neurons contributes to an excitatory threshold that fosters their conversion to inhibitory activity. We addressed this possibility by culturing murine embryonic neurons on multi-electrode arrays.

Post-synthesis modification of a metal-organic framework to form metallosalen-containing MOF materials.

A series of metallosalen-based metal-organic frameworks (MOFs) have been prepared by the post-synthesis modification of Mn(III)SO-MOF, a Mn(3+)(salen)-based MOF. Treatment of Mn(III)SO-MOF with H(2)O(2) effects the removal of the Mn(3+) ions from the salen struts, which can then be remetalated with a variety of metal precursors to form isostructural MSO-MOF materials. The presence of the new metallosalen struts in MSO-MOF was fully confirmed by ICP-OES, MALDI-TOF MS, PXRD, and TGA.

Active-site-accessible, porphyrinic metal-organic framework materials.

On account of their structural similarity to cofactors found in many metallo-enzymes, metalloporphyrins are obvious potential building blocks for catalytically active, metal-organic framework (MOF) materials. While numerous porphyrin-based MOFs have already been described, versions featuring highly accessible active sites and permanent microporosity are remarkably scarce. Indeed, of the more than 70 previously reported porphyrinic MOFs, only one has been shown to be both permanently microporous and contain internally accessible active sites for chemical catalysis.

Selective surface and near-surface modification of a noncatenated, catalytically active metal-organic framework material based on Mn(salen) struts.

From a combination of chiral Mn(salen) struts and the tetratopic ligand tetrakis(4-carboxyphenyl)benzene, a large-pore, noncatenated metal-organic framework (MOF) material, MnSO-MOF, has been synthesized. Following solvent exchange with hydrophobic CHCl(3), treatment of MnSO-MOF with aqueous H(2)O(2) allowed for the selective demetalation of Mn(salen) struts at and near the surface of the crystals. The resulting crystals displayed greatly enhanced size-selective catalysis compared to the as-synthesized material.

A catalytically active, permanently microporous MOF with metalloporphyrin struts.

Through the use of the tetratopic ligand 1,2,4,5-tetrakis(4-carboxyphenyl)benzene as a key building block, a permanently microporous metal-organic framework with Lewis acidic (porphyrin)Zn struts, ZnPO-MOF, can be made in high yields. ZnPO-MOF can efficiently catalyze acyl-transfer reactions primarily by preconcentrating the substrates within its pores, in stark contrast to analogous supramolecular systems.