Smart molecules at work-mimicking advanced logic operations

Molecular logic is an interdisciplinary research field, which has captured worldwide interest. This tutorial review gives a brief introduction into molecular logic and Boolean algebra. This serves as the basis for a discussion of the state-of-the-art and future challenges in the field. Representative examples from the most recent literature including adders/subtractors, multiplexers/demultiplexers, encoders/decoders, and sequential logic devices (keypad locks) are highlighted. Other horizons, such as the utility of molecular logic in bio-related applications, are discussed as well

Molecules for security measures: From keypad locks to advanced communication protocols

The idea of using molecules in the context of information security has sparked the interest of researchers from many scientific disciplines. This is clearly manifested in the diversity of the molecular platforms and the analytical techniques used for this purpose, some of which we highlight in this Tutorial Review. Moreover, those molecular systems can be used to emulate a broad spectrum of security measures. For a long time, molecular keypad locks enjoyed a clear preference and the review starts off with a description of how these devices developed. In the last few years, however, the field has evolved into something larger. Examples include more complex authentication protocols (multi-factor authentication and one-time passwords), the recognition of erroneous procedures in data transmission (parity devices), as well as steganographic and cryptographic protection

An acido- and photochromic molecular device that mimics triode action

© The Royal Society of Chemistry 2016. The photo-controlled shift of pH titration curves, describing the acidochromic behaviour of a spiropyran switch network, was harnessed for the realisation of a molecular triode. The intricate network can be correctly interpreted with respect to the pH dependence of the main involved species

Molecular Logic: From Single Logic Gates to Sophisticated Logic Circuits, from Fundamental Science to Practical Applications

[No abstract available

Site-selective installation of BASHY fluorescent dyes to Annexin V for targeted detection of apoptotic cells

Fluorophores are indispensable for imaging biological processes. We report the design and synthesis of azide-tagged boronic acid salicylidenehydrazone (BASHY) dyes and their use for site-selective labelling of Annexin V. The Annexin V-BASHY conjugate maintained function and fluorescence as demonstrated by the targeted detection of apoptotic cells.We thank FCT Portugal (Doctoral Fellowship, SFRH/BD/94779/2013 to F. M. F. S., Postdoctoral Fellowship, SFRH/BPD/103172/2014 to P. M. S. D. C.; projects PTDC/QUI-QUI/118315/2010 and PTDC/BBB BQB/0506/2012; PTDC/QEQ-QOR/1434/2014: PTDC/SAUFAR/119389/2010; FCT Investigator to G. J. L. B. and P. M. P. G.; iMed.ULisboa grant UID/DTP/04138/2013), EU (Marie-Curie CIG to G. J. L. B.; Marie-Sklodowska Curie ITN ProteinConjugates to G. J. L. B. and P. M. P. G.), DFG (SI 2117/1-1 to F. S.), CNPq Brazil (fellowship 200456/2015-6 to J. B. B.); Ministerio de Economía y Competitividad, Madrid, Spain (grant CTQ2014-54729-C2-1-P), Junta de Andalucía (grant P12-FQM-2140) and the EPSRC (G. J. L. B.) for financial support. G. J. L. B. is a Royal Society University Research Fellow and the recipient of a European Research Council Starting Grant (TagIt)

Engineering the BASHY Dye Platform toward Architectures with Responsive Fluorescence

A set of nine boronic-acid-derived salicylidenehydrazone (BASHY) complexes has been synthesized in good to very good chemical yields in a versatile three-component reaction. In an extension to previous reports on this dye platform, the focus was put on the electronic modification of the “vertical” positions of the salicylidenehydrazone backbone. This enabled the observation of fluorescence quenching by photoinduced electron transfer (PeT), which can be reverted by the addition of acid in organic solvent (OFF-ON fluorescence switching). The resulting emission is observed in the green-to-orange spectral region (maxima at 520–590 nm). In contrast, under physiological pH conditions in water, the PeT process is inherently decativated, thereby enabling the observation of fluorescence in the red-to-NIR region (maxima at 650–680 nm) with appreciable quantum yields and lifetimes. The latter characteristic supported the application of the dyes in fluorescence lifetime imaging (FLIM) of live A549 cells.This work was generously supported by the Portuguese Fundação para a Ciência e Tecnologia [grants PTDC/QUI-OUT/3989/2021 (P.G.); institutional grants UIDB/04138/2020 and UIDP/04138/2020 (iMed)], the Spanish Ministerio de Ciencia e Innovación [grants CTQ2017-89832-P, PID2020-119992GB-I00 (both to U.P.), and PID2019-104293GB-I00 (F.N.)], the Consejería de Universidad, Investigación e Innovación/Junta de Andalucía [grant P18-FR-4080 (U.P.)], and the Universidad de Huelva/Junta de Andalucía [UHU202070 (U.P.)]. The NMR spectrometers are part of the Portuguese National NMR Network (PT NMR) and are partially supported by Infrastructure Project No. 022161 (co-financed by FEDER through COMPETE 2020, POCI, PORL, and FCT through PIDDAC). We also acknowledge the Supercomputing and Bioinformatics Centre (SCBI) of the University of Málaga for providing the computer resources used for the theoretical calculations

All-Photonic Multifunctional Molecular Logic Device

Photochromes are photoswitchable, bistable chromophores which, like transistors, can implement binary logic operations. When several photochromes are combined in one molecule, interactions between them such as energy and electron transfer allow design of simple Boolean logic gates and more complex logic devices with all-photonic inputs and outputs. Selective isomerization of individual photochromes can be achieved using light of different wavelengths, and logic outputs can employ absorption and emission properties at different wavelengths, thus allowing a single molecular species to perform several different functions, even simultaneously. Here, we report a molecule consisting of three linked photochromes that can be configured as AND, XOR, INH, half-adder, half-subtractor, multiplexer, demultiplexer, encoder, decoder, keypad lock, and logically reversible transfer gate logic devices, all with a common initial state. The system demonstrates the advantages of light-responsive molecules as multifunctional, reconfigurable nanoscale logic devices that represent an approach to true molecular information processing units

OFF-ON-OFF Fluorescence Switch with T-Latch Function

A novel molecular system with characteristics of an OFF-ON-OFF fluorescence switch was designed to integrate the function of a T-latch. In detail, a receptor(1)-fluorophore-receptor(2) architecture was adopted to achieve fluorescence switching upon addition of protons

An All-Photonic Molecule-Based D Flip-Flop

The photochromic fluorescence switching of a fulgimide derivative was used to implement the first molecule-based D (delay) flip-flop device, which works based on the principles of sequential logic. The device operates exclusively with photonic signals and can be conveniently switched in repeated cycles. \ua9 2011 American Chemical Society

BASHY Dyes Are Highly Efficient Lipid Droplet-Targeting Photosensitizers that Induce Ferroptosis through Lipid Peroxidation

Ferroptosis is an iron-dependent lipid-peroxidation-driven mechanism of cell death and a promising therapeutic target to eradicate cancer cells. In this study, we discovered that boronic acid-derived salicylidenehydrazone (BASHY) dyes are highly efficient singlet-oxygen photosensitizers (PSs; Φ up to 0.8) that induce ferroptosis triggered by photodynamic therapy. The best-performing BASHY dye displayed a high phototoxicity against the human glioblastoma multiform U87 cell line, with an IC value in the low nanomolar range (4.40 nM) and a remarkable phototoxicity index (PI > 22,700). Importantly, BASHY dyes were shown to accumulate in lipid droplets (LDs) and this intracellular partition was found to be essential for the enhanced phototoxicity and the induction of ferroptosis through lipid peroxidation. The safety and phototoxicity of this platform were validated using an in vivo zebrafish model (Danio rerio