[Show abstract][Hide abstract] ABSTRACT: Multiple logic functions including dual-input dual-output NOR and AND gates, dual-input dual-output NOT and AND gates, and a three-input NOR gate are fabricated with fluorene-based small molecule/DNA probes (named FSM/DNA probes), which sequences are well-designed. The FSM/DNA probes can be quenched by dsDNA, aptamer-target complex and free dyes (SG I and EB) without the attachment of additional quencher moiety. The quencher-free FSM/DNA probe also presents a way for detection of ATP. In addition, the feasibility of a pH-induced “ON–OFF” fluorescence switching system is demonstrated through the carboxylic acid-terminated fluorene derivatives (F(COOH)2 and FSM/DNA probe) by taking advantage of protonation/deprotonation process occurring at the carboxylic acid functional groups. The formation of deprotonated F(COO–)2 emits fluorescent (“ON” state) at neutral and alkaline pH ranges, whereas the F(COOH)2 with the protonated carboxylic acid groups quenches the emission of fluorene (“OFF” state) at acidic pH ranges. Switching function based on the FSM/DNA probe can be performed in totally aqueous solution. Interestingly, the FSM/DNA probe exhibits high fluorescence brightness, biocompatibility, cell membrane penetrability, and thus it has been applied in live cell imaging investigation.
The Journal of Physical Chemistry C. 04/2014; 118(18):9368–9376.
[Show abstract][Hide abstract] ABSTRACT: A new easily-accessible solution-processed oligomer, with an isoindigo group as an electron acceptor and a thieno[3,2-b]thiophene ﬂanked by thiophenes as electron donors, has been synthesized by a Stille coupling reaction. Through introducing the extended π-conjugated groups into isoindigo, the electro-optical properties of the material can be fine-tuned. The isoindigo oligomer has a broad absorption in the region from 300 to 800 nm with a narrow bandgap (1.54 eV), which is believed to be an ideal bandgap as donor materials. The oligomer possesses low HOMO energy level (−5.39 eV). The potential of optical and electronic properties encouraged us to explore the photovoltaic performance using the oligomer as the donor material in bulk heterojunction organic solar cell along with 6,6-phenyl-C61-butyric acid methyl ester as the acceptor. The solar cell based on the oligomer with an inverted device configuration provided a power conversion efficiency of 1.41% under the AM 1.5G illumination with an intensity of 100 mW cm−2 from a solar simulator.
Dyes and Pigments 07/2013; 98(1):11–16. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Fluorene-based small molecules (FSMs) have optical properties and can interact with DNA. In this paper, the integrated "INH" and "AND" gates operating in parallel are developed with the fluorene-based small molecule (FSM)/DNA probe. They are activated by taking advantage of the two-step fluorescence resonance energy transfer (FRET) process and the sequence-recognition mechanism of DNA. Then, a "NOT" gate is obtained with a molecular beacon-like probe (FSM-MB) by using the FSM as the fluorophore. Moreover, the "NOT" gate based on the FSM-MB probe can be used as a biosensor and has potential applications in label-free detection of target molecules.
[Show abstract][Hide abstract] ABSTRACT: Design of elementary molecular logic gates is the key and the fundamental of performing complicated Boolean calculations. Herein, we report a strategy for constructing a DNA-based OR gate by using the mechanism of sequence recognition and the principle of fluorescence resonance energy transfer (FRET). In this system, the gate is entirely composed of a single strand of DNA (A, B and C) and the inputs are the molecular beacon probes (MB1 and MB2). Changes in fluorescence intensity confirm the realization of the OR logic operation and electrophoresis experiments verify these results. Our successful application of DNA to perform the binary operation represents that DNA can serve as an efficient biomaterial for designing molecular logic gates and devices.