Photoinduced electron transfer (PeT) based fluorescent probes for cellular imaging and disease therapy

Abstract

Typical PeT-based fluorescent probes are multi-component systems where a fluorophore is connected to a recognition/activating group by an unconjugated linker.

Synthesis of 3,4-dihydroxy-1,8-naphthalimides with inbuilt catechol and crown ether functionalities

“…The filtrate was transferred to a round bottom flask and the solvent was removed in vacuo to afford Nap-Cat (214 mg, 77%) as a yellow powder. 1 [1,4,7,10,13]pentaoxacyclopentadecino[2,3-g]isoquinoline-4,6(5H)-dione (Nap-Crown). To a stirring solution of tetraethylene glycol di( p-toluenesulfonate) (2.25 g, 4.47 mmol, 2.0 equiv.)…”

“…The inherent properties of the 1,8-naphthalimide scaffold-high quantum yields, large Stokes shifts and photostability-have led to them being widely employed as fluorescent sensors and imaging agents. [1][2][3][4][5] A number of researchers have developed mono-substituted 1,8-naphthalimides for a variety of uses, including the recognition of anions 1,6 and cations, [7][8][9] the monitoring of enzyme function, 10 as fluorescent sensors, 11,12 as cellular stains and dyes, [13][14][15] and as selective histone deacetylase inhibitors. [16][17][18][19][20] 4-Amino-1,8-naphthalimides have traditionally been the focus of fluorophore development due to well-established syntheses by nucleophilic aromatic substitution chemistry.…”

Recent Advances in the Development of Near-Infrared Fluorescent Probes for the in Vivo Brain Imaging of Amyloid-β Species in Alzheimer’s Disease

“…The structure–property relationship that governs this phenomenon is explained by two processes, acceptor-excited PeT (a-PeT) and donor-excited PeT (d-PeT) depending on the electron transfer direction. The transfer of electrons occurs between the recognition group to the fluorophore in a-PeT and fluorophore to the recognition group for d-PeT, e.g., Rho1-Cu–Rho4-Cu . Recently emerged RET-based probes exhibit nonradiative transfer of energy between the donor group and the recipient in appropriate proximity, such as Förster resonance energy transfer (FRET) and chemiluminescence resonance .…”

Enhanced β-Amyloid Aggregation in Living Cells Imaged with Quinolinium-Based Spontaneous Blinking Fluorophores

“…29,30 The forbidden emission of the zero vibrational energy level of TICT states can greatly reduce the fluorescence quantum yield, which facilitates the design of "turn-on" fluorescent probes. 31,32 In this regard, a rotatable single bond is further introduced to design a "turn-on" probe responsive to Aβ aggregates (Figure 1). As aryl rings may interact with Aβ 1−40 aggregates via hydrophobic interactions, the steric hindrance of the aromatic side chain is important for controlling the binding affinity between the probes and Aβ 1−40 aggregates.…”