Thiophene and diaminobenzo- (1,2,5-thiadiazol)- based DAD-type near-infrared fluorescent probe for nitric oxide: A theoretical research

Abstract

A near-infrared fluorescent probe (LS-NO) for the real-time detection of nitric oxide (NO) in inflammatory bowel disease (IBD) was developed recently. The probe used oligoglycol morpholine-functionalized thiophene as strong electron donors and diaminobenzene (1,2,5-thiadiazole) as a weak electron acceptor and NO trapping group. It could detect exogenous and endogenous NO in the lysosomes of living cells with high sensitivity and specificity. To further understand the fluorescent mechanism and character of the probes LS-NO and LS-TZ (after the reaction of the probe LS-NO with NO), the electron transfer in the excitation and emitting process within the model molecules DAD-NO and DAD-TZ was analyzed in detail under the density functional theory. The calculation results indicated the transformation from diaminobenzene (1,2,5-thiadiazole) as a weak electron acceptor to triazolo-benzo-(1,2,5-thiadiazole) as a strong electron acceptor made LS-NO an effective “off–on” near-infrared NO fluorescent probe.

Recent progress of organic fluorescent molecules for bioimaging applications: cancer-relevant biomarkers

“…NO is an important signaling transduction and effector small molecule generally produced in anoxic reactions, which is beneficial for improving oxygen supply and blood flow. 30 The NO appearing in tumor cells is known to promote tumor progression by inducing tumor proliferation and the expression of angiogenic factors. 31 So designing fluorescent probes with the ability to image NO in a tumor environment is of great interest for applications.…”

Theoretical Insights into a Near-Infrared Fluorescent Probe NI-VIS Based on the Organic Molecule for Monitoring Intracellular Viscosity

“…The processes of the conformation search for probe NI-VIS were as follows: Using Confab [ 36 ] to obtain initial conformations of probe NI-VIS; The batch structural optimization was conducted using Crest to invoke xtb program under the GFN2-xTB method [ 37 ]; Invoke isostat in Molclus [ 38 ] program to screen out the several stable probe conformations with the local lowest free energy; The corresponding ground and excited state of different probe conformation’s structure optimization and vibrational frequency analysis on the stable probe conformations’ structure obtained from step (3) were conducted by using the ORCA program [ 39 ] under CAM-B3LYP/def2-TZVPD, a functional which was testified to be suitable for the excited state optimization with charge transfer character, with D3 dispersion correction and GCP correction to remove artificial overbinding effects from BSSE [ 40 , 41 , 42 , 43 , 44 , 45 ]. The functional and basis set combination wB2GP-PLYP/def2-TZVPD was used in a single point energy calculation to obtain the free energy with high precision [ 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 ]. Most of the figures in this work were rendered by means of VMD 1.9.3 software [ 55 ] and the analyses were finished by using the Multiwfn 3.8(dev) code [ 56 ].…”

A Single Organic Fluorescent Probe for the Discrimination of Dual Spontaneous ROS in Living Organisms: Theoretical Approach

“…F. Goppelsroder built a fluorescent sensor that was used for the detection of Al 3+ through fluorescence enhanced after chelate formation from mulberry pigment dye with the Al 3+ ligand. Afterwards, a large number of fluorescent probes for the detection of different kinds of targets were developed [4][5][6][7][8][9][10][11][12][13]. Nowadays, fluorescent probes based on small organic molecules have been widely expanded in food detection, environmental monitoring, clinical examination, and many other fields.…”