Room‐Temperature Phosphorescence Resonance Energy Transfer for Construction of Near‐Infrared Afterglow Imaging Agents

Abstract

Afterglow imaging that detects photons after cessation of optical excitation avoids tissue autofluorescence and thus possesses higher sensitivity than traditional fluorescence imaging. Purely organic molecules with room‐temperature phosphorescence (RTP) have emerged as a new library of benign afterglow agents. However, most RTP luminogens only emit visible light with shallow tissue penetration, constraining their in vivo applications. This study presents an organic RTP nanoprobe (mTPA‐N) with emission in the NIR range for in vivo afterglow imaging. Such a probe is composed of RTP molecule (mTPA) as the phosphorescent generator and an NIR‐fluorescent dye as the energy acceptor to enable room‐temperature phosphorescence resonance energy transfer (RT‐PRET), ultimately resulting in redshifted phosphorescent emission at 780 nm. Because of the elimination of background noise and redshifted afterglow luminescence in a biologically transparent window, mTPA‐N permits imaging of lymph nodes in living mice with a high signal‐to‐noise ratio. This study thus opens up a universal approach to develop organic RTP luminogens into NIR afterglow imaging agents via construction of RT‐PRET.

One-axis Two-wing Guest-Host Strategy for Constructing Ultralong-lifetime Near-infrared Organic Phosphorescence Materials for Bioimaging

“…To ensure our DMAPy/BPO NPs were accessible in vivo with good RTP performance, a top-down method was employed to produce the NPs. [48,49] To verify the advantages of long-wavelength RTP materials, a short-wavelength (λ Phos . = 520 nm) but strong intensity (Ф Phos .…”

“…[1][2][3][4][5][6][7][8][9][10] Therefore, constructing organic RTP materials would bene t tissue imaging, tumor diagnosis, and drug tracking. [10][11][12][13][14][15] To date, most phosphorescent materials have poor biological tissue permeability because the wavelengths of their emission spectra are short (less than 580 nm). [16][17][18][19][20][21][22][23][24][25][26][27] This only means phosphors provide good imaging in shallow regions of an organism.…”

Activating Room-Temperature Phosphorescence of Organic Luminophores via External Heavy-Atom Effect and Rigidity of Ionic Polymer Matrix

“…Compared with fluorescent materials, materials with room-temperature phosphorescence (RTP) have received special attention for their larger Stokes shift and longer lifetime (6)(7)(8)(9)(10)(11)(12)(13). These advantages promote their applications in the fields such as molecular switches (14)(15)(16)(17)(18), organic light-emitting diodes (OLEDs) (19)(20)(21)(22)(23), anticounterfeiting (24) and bioimaging (25). As pure organic molecules typically emit phosphorescence only at low temperature (e.g., 77 K) and under inert conditions (26,27), traditional phosphorescent materials focus on inorganic and organometallic systems (28,29), which normally rely on noble metals like iridium and platinum to promote the intersystem crossing (ISC) process.…”

Activating Room-Temperature Phosphorescence of Organic Luminophores via External Heavy-Atom Effect and Rigidity of Ionic Polymer Matrix

“…Compared with fluorescent materials, materials with room-temperature phosphorescence (RTP) have received special attention for their larger Stokes shift and longer lifetime (6)(7)(8)(9)(10)(11)(12)(13). These advantages promote their applications in the fields such as molecular switches (14)(15)(16)(17)(18), organic light-emitting diodes (OLEDs) (19)(20)(21)(22)(23), anticounterfeiting (24) and bioimaging (25). As pure organic molecules typically emit phosphorescence only at low temperature (e.g., 77 K) and under inert conditions (26,27), traditional phosphorescent materials focus on inorganic and organometallic systems (28,29), which normally rely on noble metals like iridium and platinum to promote the intersystem crossing (ISC) process.…”