All-photonic molecular half-adder

One molecule acts as both an AND and an XOR Boolean logic gate that share the same two photonic inputs. The molecule comprises a half-adder, adding two binary digits with only light as inputs and outputs, and consists of three covalently linked photochromic moieties, a spiropyran and two quinoline-derived dihydroindolizines. The AND function is based on the absorption properties of the molecule, whereas the XOR function is based on an off-on-off response of the fluorescence to the inputs that results from interchromophore excited-state quenching interactions. The half-adder is simple to operate and can be cycled many times.     

Aminoanthraquinone-based chemosensors: colorimetric molecular logic mimicking molecular trafficking and a set-reset memorized device

The synthesis, photophysical properties, protonation and metal-ion coordination features of a family of four (3-6) anthraquinone-based schiff base derivatives are reported. The outstanding UV-vis absorption properties of the 1-aminoanthraquinone chromophore allowed the efficient visual detection and quantification of Cu(2+) and/or Ni(2+) in buffered aqueous solution. Analysis of spectrophotometric data with SPECFIT yielded the macroscopic and microscopic stability constants of the complexes. Furthermore, the different optical output signals (i.e. absorbance) observed with addition of various metal ions to a solution of 6 can be used for mimicking the operation of a traffic signal and "Set-Reset" molecular level information processing device.     

分子逻辑的研究进展

简要介绍了分子逻辑的研究现状和近年来的研究进展,展望了该领域的发展前景。     

A parallel electromagnetic molecular logic gate

A theoretical study of transport through a three-terminal molecular ring in the presence of a magnetic field is presented. The physical principles necessary to achieve logic operations based on the Aharonov-Bohm effect are discussed. We show that a proper combination of a gate potential and a realistic magnetic field can be used to obtain parallel logic operations such as AND and AND+NOT.     

Orthogonal addressable monolayers for integrating molecular logic

Plug and play: The mimicking of integrated circuits by using two individual monolayers (molecular chips) is shown. These monolayers can be individually addressed using identical inputs. Upon combination of their optical outputs, the input/output characteristics of a molecular encoder is obtained. Since the encoder functionality is only displayed when both chips are active, the device behaves according to a plug-and-play principle (In=input; see picture).     

DNA-based logic gates operating as a biomolecular security device

The first example of a nucleic acid-based molecular keypad lock has been constructed by taking advantage of the sequence-specific recognition ability of DNA and solid-phase substrates.     

Multiple molecular logic functions and molecular calculations facilitated by surfactant's versatility

Two isomeric compounds and , combining intramolecular charge transfer (ICT) and photoinduced electron transfer (PET) mechanisms together, were designed and used as logic gates with configurable multiple outputs; ten different logic functions (AND, NAND, OR, NOR, XNOR, INHIBIT, YES, NO, PASS 1 and PASS 0) were achieved by varying the inputs threshold or by altering the inputs; furthermore, half addition and half subtraction were performed within (or ); the concept demonstrated here may provide a strategy for constructing more integrated molecular level devices with multiple functions.     

Consolidating molecular AND logic with two chemical inputs

A novel molecular AND logic gate 1 is demonstrated based on the competition between fluorescence and photoinduced electron transfer (PET). It is constructed according to a 'receptor2-spacer-fluorophore-spacer-receptor1-spacer-fluorophore-spacer-receptor2' format where receptor1 is a tertiary amine, receptor2 is a benzo-15-crown-5 ether and the fluorophore is an anthracene moiety, which are separated from each other by methylene spacers. The fluorescence response in methanol is significantly enhanced only when both H+ and Na+ are the inputs at high enough concentrations in accordance with AND logic. Cs+ behaves similarly to Na+, but with a lower fluorescence enhancement, whereas the other alkali metal cations are not effective. Electrospray ionization mass spectrometry provides evidence for formation of 1:1 and 1:2 (1:metal) complexes with alkali cations, and formation of a 1:2:1 (1:metal:proton) complex in the additional presence of acid.     

A potential and ion switched molecular photonic logic gate

A molecular photonic logic gate is demonstrated by integrating electrical (potential) and chemical (ionic) switching functions into molecules attached at an externally addressable semiconductor substrate.     

Boolean and fuzzy logic implemented at the molecular level

In this work, it is shown how to implement both hard and soft computing by means of two structurally related heterocyclic compounds: flindersine (FL) and 6(5H)-phenanthridinone (PH). Since FL and PH have a carbonyl group in their molecular skeletons, they exhibit Proximity Effects in their photophysics. In other words, they have an emission power that can be modulated through external inputs such as temperature (T) and hydrogen-bonding donation (HBD) ability of solvents. This phenomenology can be exploited to implement both crisp and fuzzy logic. Fuzzy Logic Systems (FLSs) wherein the antecedents of the rules are connected through the AND operator, are built by both the Mamdani’s and Sugeno’s models. Finally, they are adopted as approximators of the proximity effect phenomenon and tested for their prediction capabilities. Moreover, FL as photochromic compound is also a multiply configurable crisp logic molecular element.     

A fluorescent molecular logic gate with multiply-configurable dual outputs

A simple molecule, L, diethylenetriamine bearing anthracene fragments at both ends, behaves as a fluorescent molecular logic gate with "multiply-configurable dual outputs", capable of demonstrating five different logic functions operated by proton (H+) and transition metal cations (Mn+) as inputs.     

Stable polymeric microballoons as multifunctional device for biomedical uses: synthesis and characterization

Gas filled hollow microparticles, i.e., microbubbles and microballoons, are soft matter devices used in a number of diverse applications ranging from protein separation and purification in food science to drilling technology and ultrasound imaging. Aqueous dispersions of these mesoscopic systems are characterized by the stabilization of the air/water interface by a thin shell of phospholipid bilayer or multilayers or by a denatured and cross-linked proteic matrix. We present a study of a type of microballoons based on modified poly(vinyl alcohol), PVA, a synthetic biocompatible polymer, with new structural features. A cross-linking reaction carried out at the air/water interface provides polymeric air-filled microbubbles with average dimensions depending on the reaction temperature. Characterization of diameters and shell thicknesses for microbubbles obtained at different temperatures has been carried out. Conversion to solvent-filled hollow microcapsules is possible by soaking microbubbles in dimethyl sulfoxide. Microcapsules permeability to fluorescent labeled dextran molecular weight standards was correlated to the mesh size of the polymer network of the shell. Microbubbles were covalently grafted under very mild conditions with beta-cyclodextrin and poly-l-lysine with a view to assay the capability of the device for delivery of hydrophobic drugs or DNA. PVA based microballoons show a remarkable shelf life of several months, their external surface can be decorated with many biologically relevant molecules. These features, together with a tested biocompatibility, make them attractive candidates for use as multifunctional device for diagnosis and therapeutic purposes, i.e., as ultrasound reflectors in ecographic investigation and as drug platforms for in situ sonoporation.     

Approaches to polymer superlattice and molecular device

Approaches to polymer superlattice and molecular devices are shown, demonstrating with functional molecule material by incorporation of a functional molecule into the conducting polymer, conjugating copolymer superlattice by a novel potential programmed electro polymerization, ultrahigh anisotropic conductive LB heterolayers, and porphyrin arrays connected with conducting molecular wire and insulating molecular wire. These results show a practical method to fabricate ultimate functional materials such as molecular device which is the smallest functional material, and quantum functional material which creates a novel nature.     

Chemical approaches to molecular logic elements for addition and subtraction

Molecular and supramolecular logic gates are candidates for computation at the nanoscale level. Nowadays all common logic operations can be mimicked with molecular devices based on chemical approaches. One step further towards molecular systems with increased logic capabilities is the addition or subtraction of binary digits. This Minireview describes recent developments to attain this goal, including bioinspired systems based on DNA and enzymes. Furthermore, chemical molecular logic gates are discussed and compared critically with regard to alternative concepts.     

Input-dependent induction of oligonucleotide structural motifs for performing molecular logic

The K(+)-H(+)-triggered structural conversion of multiple nucleic acid helices involving duplexes, triplexes, G-quadruplexes, and i-motifs is studied by gel electrophoresis, circular dichroism, and thermal denaturation. We employ the structural interconversions for perfoming molecular logic operations, as verified by fluorimetry and colorimetry. Short G-rich and C-rich cDNA and RNA single strands are hybridized to produce four A-form and B-form duplexes. Addition of K(+) triggers the unwinding of the duplexes by inducing the folding of G-rich strands into DNA- or RNA G-quadruplex mono- and multimers, respectively. We found a decrease in pH to have different consequences on the resulting structural output, depending on whether the C-rich strand is DNA or RNA: while the protonated C-rich DNA strand folds into at least two isomers of a stable i-motif structure, the protonated C-rich RNA strand binds a DNA/RNA hybrid duplex to form a Y·RY parallel triplex. When using K(+) and H(+) as external stimuli, or inputs, and the induced G-quadruplexes as reporters, these structural interconversions of nucleic acid helices can be employed for performing logic-gate operations. The signaling mode for detecting these conversions relies on complex formation between DNA or RNA G-quadruplexes (G4) and the cofactor hemin. The G4/hemin complexes catalyze the H(2)O(2)-mediated oxidation of peroxidase substrates, resulting in a fluorescence or color change. Depending on the nature of the respective peroxidase substrate, distinct output signals can be generated, allowing one to operate multiple logic gates such as NOR, INH, or AND.     

Dependence of the cyclization behavior of multifunctional network molecules on molecular size

The tendency for cyclization of nonlinear network molecules is quantitatively expressed by the cyclization probability, defined as the ratio of cyclization to total reaction rate. In contrast to branching, the rate of cyclization depends on the configurational statistical mechanics of segments joining functional groups. Direct integration of the joint configurational probability density in the subspace of encounters yields the distribution of the number of configurationally formed intramolecular functional group encounters (nearest neighbors). Statistically independent network segments are assumed to obey the Gaussian statistics. A recursive relationship for the distribution of chain lengths is developed, and it is shown that for large molecular sizes this relationship tends to a limiting distribution. Corresponding average and standard deviation follow power law dependence on degree of polymerization (DP). With these results, cyclization probabilities are explicitly expressed as functions of DP. When segmental diffusion is the rate controlling factor, cyclization is similar to short range (or primary) cyclization. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 861–870, 2005