Dansylamide

Molecularly Imprinted Nanogels Possessing Dansylamide Interaction Sites for Controlling Protein Corona In Situ by Cloaking Intrinsic Human Serum Albumin

Nanomaterials have become increasingly promising for biomedical applications owing to their specific biological characteristics. As drug delivery vehicles, nanomaterials have to circulate in the bloodstream to deliver the encapsulated components to the target tissues. Protein corona regulation is one of the promising approaches that gives stealth capability to avoid immune response. The aim of this study was to develop molecularly imprinted polymer nanogels (MIP-NGs) capable of protein corona regulation, using intrinsic human serum albumin (HSA) and with a functional monomer, dansylamide ethyl acrylamide (DAEAm), the dansylamide group serving as a ligand for HSA. The recognition capability of HSA for MIP-NGs was investigated by isothermal titration calorimetry (ITC). The affinity of the MIP-NGs prepared with DAEAm was then compared to that of the reference MIP-NGs prepared with pyrrolidyl acrylate developed in our previous study. Furthermore, we demonstrated that the concurrent use of these two different functional monomers for molecular imprinting was further effective to construct high-affinity recognition nanocavities for HSA and to form HSA-rich protein corona in the human plasma owing to the different interaction modes of the monomers. We believe that the molecular imprinting strategy developed through the use of ligand-based functional monomer is an effective strategy to create artificial molecular recognition materials.

Interaction of aromatic compounds and anions with naphthylimide-dansylamide fluorescent dyad: Experimental evidence of aryl C-H…π and aryl C-H…anion contacts and DFT calculations

In this work the interaction of halide anions and simple aromatic compounds with a bichromophoric fluorescent dyad derived from 1,8-naphthalimide (NAPIM) and 5-(dimethylamino)naphthalene-1-sulfonyl (DANS) was studied using electronic spectroscopy, ¹H, and ¹⁹F NMR spectroscopy and quantum chemistry modeling (b3lyp/def2-TZVP). The NAPIM-DANS dyad interacts with electron-rich guests with binding constants in the range of 6×10³ to 8×10³M^-1 in CHCl₃. The formed complexes are stabilized through aryl C-H … anion and aryl C-H … π interactions.

A Fluorescence Study on Binding Interaction of N-acetylated Dansylamide Conjugates with β-cyclodextrin, Tween-20 and DPPC Lipid Bilayer Membrane

The present work describes the photophysical behavior of a saturated fatty acid (palmitic acid) containing N-acetylated dansylamide derivative (DAN-PA) into biologically important organized assembly such as β-cyclodextrin (β-CD), Tween-20 (T-20) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid bilayer membrane. The results were compared by using another N-acetylated dansylamide conjugate having a short hydrophobic tail, DAN-ACYL. Long hydrophobic tail (saturated fatty acid) containing dansylamide conjugate (DAN-PA) shows more efficient binding interactions with the β-CD as compared to the short tail containing dansylamide derivative (DAN-ACYL). The calculated binding constants values of DAN-PA and DAN-ACYL probes are 1.35 × 10² M ^-1 and 0.31 × 10² M ^-1 respectively. The DAP-PA is a sensitive fluorophore for understanding the micellization process in T-20, as compared to the DAN-ACYL because it shows a significant change in fluorescent properties (steady-state and time-resolved both) with changing in T-20 concentrations. The calculated CMC value for T-20 surfactant is 0.07 mM. While the DAN-ACYL does not show any change in the fluorescent properties while changing the T-20 concentrations. Fluorescent parameters like steady-state and time-resolved of DAN-PA are quite sensitive towards the thermo-tropic phase transitional changes into lipid bilayer membrane properties. And the calculated thermo-tropic phase transition temperature by using DAN-PA fluorophore is 42 °C.

Fluorescence of N-acylated dansylamide with a long hydrophobic tail: sensitive response to premicellar aggregation of sodium deoxycholate

The present work describes the synthesis and photophysical studies of two fluorescent dansylamide derivatives, in which the amine group is acylated by a long hydrophobic chain (a part of a biologically relevant palmitic acid) and by a short hydrophobic tail (a part of acetic acid). The long chain tethered dansyl analogue is successfully utilized in estimating critical micellar concentration (CMC) of bile salts (NaDC, NaC) as well as anionic and cationic surfactants (SDS, CTAB) with the help of enhanced fluorescence intensity facilitated by better solubilization of the molecule in microheterogeneous media. The long chain tethered dansylamide derivative shows significant fluorescence solvatochromism with a red shift (ca. 4000 cm(-1)) from hexane to water. In contrast, the solvatochromism exhibited by the parent/short acyl chain analogue is much less (ca. 2230 cm(-1) from hexane to water) and the fluorescence is not sensitive to micellization. Interestingly, the long chain tethered fluorescent probe shows high sensitivity towards premicellar aggregation of sodium deoxycholate (NaDC) bile salt, through a clear blue shift of emission maxima and concomitant enhancement of fluorescent intensity. Such an observation of fluorescence sensing of premicellar aggregation is unusual.

N-(3-Imidazolyl)propyl dansylamide as a selective Hg(2+) sensor in aqueous media through electron transfer

N-Imidazolylpropyl dansylamide 1 was synthesized for the sensing of metal ions and found to be selective and sensitive toward Hg(2+) ions in a PBS-EtOH (1:4, pH=7.4) solution. The sensing ability of probe 1 was examined by UV-Vis, fluorescence, and (1)H NMR spectroscopy. The sensing of Hg(2+) exhibited a quenching of emission band at λmax=515 nm of probe 1, which was associated with quenching of green fluorescence emission under 365 nm illumination. Probe 1 showed a good association constant with Hg(2+) (Ka=6.48×10(4) M(-1)) with a stoichiometry of 1:1 in PBS-EtOH (1:4, pH=7.4) having the lowest detection limit of 1 μM for Hg(2+); on the other hand, probe 2, which has no imidazole moiety, was not able to detect any metal ion. In the case of probe 1, electrons on the imidazole nitrogen are available for electron transfer (ET), which was responsible for its green emission band that was quenched on addition of Hg(2+); this clearly indicates that these electrons were used for the formation of a coordinate bond with Hg(2+) and that ET was switched off.