Bright AIE Nanoparticles with F127 Encapsulation for Deep‐Tissue Three‐Photon Intravital Brain Angiography

Abstract

Deep-tissue imaging is of great significance to biological applications. In this paper, a deep-red emissive luminogen 2,3-bis(4'-(diphenylamino)-[1,1'-biphenyl]-4-yl) fumaronitrile (TPATCN) with aggregation-induced emission (AIE) feature is prepared. TPATCN molecules were then encapsulated within a polymeric matrix of Pluronic F-127 to form nanoparticles (NPs). TPATCN NPs exhibit bright three-photon fluorescence (3PF) in deep-red region, together with high chemical stability, good photostability, and biocompatibility. They are further utilized for in vivo 3PF imaging of the brain vasculature of mice, under the excitation of a 1550 nm femtosecond laser. A vivid 3D reconstruction of the brain vasculature is then built with a penetration depth of 875 µm, which is the largest in ever reported 3PF imaging based on AIE NPs. After that, by collecting both of the 3PF and third-harmonic generation signals, multichannel nonlinear optical imaging of the brain blood vessels is further realized. These results will be helpful to study the structures and functions of the brain in the future.

Utilizing a Pyrazine‐Containing Aggregation‐Induced Emission Luminogen as an Efficient Photosensitizer for Imaging‐Guided Two‐Photon Photodynamic Therapy

“…Herein, we chose to study DCDPP‐2TPA because the dicyanopyrazine and triphenylamine units separately act as electron‐acceptor and electron‐donor moieties and provide the molecule with a D‐π‐A‐π‐D structure. Moreover, in comparison to the reported AIEgen, 2,3‐bis(4′‐(diphenylamino)‐[1,1′‐biphenyl]‐4‐yl)fumaronitrile (TPATCN), substitution of the double bond with a pyrazine ring dramatically improves the stability of the resultant molecule . DCDPP‐2TPA was prepared according to our previous study .…”

“…Moreover,i nc omparison to the reported AIEgen, 2,3-bis(4'-(diphenylamino)-[1,1'-biphenyl]-4-yl)fumaronitrile (TPATCN), substitution of the double bond with ap yraziner ing dramatically improves the stability of the resultantm olecule. [14] DCDPP-2TPAw as prepared according to our previous study. [15] By utilizing ad ifferent fabrication method,n ovel DCDPP-2TPA-encapsulated silica nanoparticles (NPs) were synthesized (Scheme 1).…”

Aggregation-induced emission luminogen for in vivo three-photon fluorescence lifetime microscopic imaging

“…According to our previous study, the 3PA cross-section ( 3 ) of DCDPP-2TPA molecule was 2:95 Â 10 À79 cm 6 s 2 at 1550 nm, much larger than most commonly used three-photon°uorescent probes (Rh6G, 3 ¼ 6 Â 10 À81 cm 6 s 2 (at 1300 nm); Fluorescein, 3 ¼ 1:63 Â 10 À83 cm 6 s 2 (at 1300 nm); wtGFP, 3 ¼ 1:59 Â 10 À81 cm 6 s 2 (at 1300 nm)). 8,[29][30][31][32] Besides, TPATCN molecule has no nonaromatic double bonds, and nanoparticles composed of substantial TPATCN molecules showed higher stability than most existing AIE NPs under highpower laser excitation. 8,33 One-photon and three-photon°uorescence spectra of DCDPP-2TPA nanoparticles in water (1 mg/mL) excited with a CW laser centered at 450 nm and a fs laser centered at 1550 nm, respectively, were recorded ( Fig.…”

Self-assembled nanostructured photosensitizer with aggregation-induced emission for enhanced photodynamic anticancer therapy

“…The AIE nanorods showed more efficient cellular uptake, higher accumulation, and deeper penetration compared with AIE nanodots. Recently, Dong et al [25,[71][72][73] also prepared several nanostructures with different morphologies based on diketopyrrolopyrrole derivatives using simple reprecipitation methods for photoacoustic imaging-guided photothermal therapy. Xie and Xu et al [74] obtained stable AIE nanoparticles (NPs) with different rod-like or spherical morphologies by assembling poly(ethylene glycol)-block-poly(L-lactic acid) (PEG 5k -PLA 10k ) or poly (ethylene glycol)-block-poly(caprolactone) (PEG 5k -PCL 10k ) with 9,10-distyrylanthracene (DSA) for noninvasive long-term imaging.…”