Photoacoustic (PA) imaging emerges as a promising technique for biomedical applications. The development of new strategies to boost PA conversion without depressing other properties (e.g., ...fluorescence) is highly desirable for multifunctional imaging but difficult to realize. Here, we report a new phenomenon that active intramolecular motions could promote PA signal by specifically increasing thermal‐to‐acoustic conversion efficiency. The compound with intense intramolecular motion exhibits amplified PA signal by elevating thermal‐to‐acoustic conversion, and the fluorescence also increases due to aggregation‐induced emission signature. The simultaneously high PA and fluorescence brightness of TPA‐TQ3 NPs enable precise image‐guided surgery. The preoperative fluorescence and PA imaging are capable of locating orthotopic breast tumor in a high‐contrast manner, and the intraoperative fluorescence imaging delineates tiny residual tumors. This study highlights a new design guideline of intramolecular motion amplifying PA effect.
A compound with intense intramolecular motions exhibits an amplified photoacoustic signal by specifically elevating the thermal‐to‐acoustic conversion efficiency, and the fluorescence brightness also increases due to the aggregation‐induced emission signature. Precise in vivo image‐guided cancer surgery in different stages is conducted, greatly boosting the surgery outcome.
Organic near-infrared (NIR) emitters with simultaneously high absorption coefficient and photoluminescence quantum yield (PLQY) are highly desirable for biomedical imaging yet seldom reported because ...these two aspects are usually contradictory. The conjugated planar structures exhibit strong absorption but the emission is seriously quenched in aggregate state, whereas the twisted unplanar molecules display opposite phenomena. Herein, we report a kind of dragonfly-shaped NIR aggregation-induced emission luminogen (AIEgen) with both high absorption coefficient (6.24 × 104 M−1 cm−1) and superior PLQY (51.2%) for precise image-guided cancer surgery. The compound possessing a conjugated structure with vibrational substitutes has been synthesized, in which the good conjugation enables strong absorption, and the molecular vibration affords AIE signature. Moreover, the nonfluorescent processes are significantly suppressed, making every effort to boost fluorescence. The highly bright and stable AIE nanoparticles warrant efficient in vitro cellular imaging and in vivo tumor imaging. Moreover, the fluorescence imaging-guided cancer surgery helps to precisely delineate tiny tumor nodules, significantly improving the cancer surgery outcome. This work will inspire more insights into the development of organic NIR emitters with high brightness for biomedical applications.
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Persistent luminescence without excitation light and tissue autofluorescence interference holds great promise for biological applications, but is limited by available materials with long‐wavelength ...emission and excellent clinical potential. Here, we report that porphyrin derivatives can emit near‐infrared persistent luminescence over 60 min after cessation of excitation light or on interaction with peroxynitrite. A plausible mechanism of the successive oxidation of vinylene bonds was demonstrated. A supramolecular probe with a β‐sheet structure was constructed to enhance the tumor targeting ability and the photoacoustic and persistent luminescence signals. Such probes featuring light‐triggered function transformation from photoacoustic imaging to persistent luminescence imaging permit advanced image‐guided cancer surgery. Furthermore, peroxynitrite‐activated persistent luminescence of the supramolecular probe also enables rapid and precise screening of immunogenic cell death drugs.
Porphyrin derivatives that can emit near‐infrared persistent luminescence (PL) over 60 min are reported and a mechanism for the phenomenon is proposed. The derivatives are used to synthesize supramolecular probes with peroxynitrite‐activated PL and light‐triggered imaging‐modality transformation characteristics that permit improved biological uses.
Conjugated polymers (CPs) that have both a high extinction coefficient (ε) and a high photothermal conversion efficiency (η) in the second near-infrared (NIR-II) region (1,000–1,700 nm) are highly ...desirable for photoacoustic imaging (PAI) and photothermal therapy (PTT). Here, we report that introducing polycyclic, auxochromic, and coplanar effects together into conjugated backbones affords isoindigo-based CPs with strong absorption and high η in the NIR-II region. Water-dispersed nanoparticles (NPs) of the typical polymer P4TTD-OT, with an ε in mass of 37.1 g−1 cm−1 and an η of 72.9% at 1,064 nm, show superior PAI properties. PAI of 40 mm depth at 1,064 nm is achieved at a lower laser fluence of 7.0 mJ cm−2 with chicken breast muscle as a model tissue, while a signal-to-background ratio of up to 42 dB is realized in the in vivo NIR-II PAI using the 4T1 tumor-bearing mouse model. The NPs can also serve as an effective NIR-II nanoagent for PAI-guided PTT.
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•A strategy for the synthesis of NIR-II-absorbing CPs is proposed•High η up to 72.9% at 1,064 nm is achieved•Tissue penetration depth of PAI signals up to 40 mm is achieved
Jiang et al. report that the combination of polycyclic, auxochromic, and coplanar effects can afford conjugated polymers with high NIR-II molar extinction coefficient and photothermal conversion efficiency.
Lysosome‐relevant cell death induced by lysosomal membrane permeabilization (LMP) has recently attracted increasing attention. However, nearly no studies show that currently available LMP inducers ...can evoke immunogenic cell death (ICD) or convert immunologically cold tumors to hot. Herein, we report a LMP inducer named TPE‐Py‐pYK(TPP)pY, which can respond to alkaline phosphatase (ALP), leading to formation of nanoassembies along with fluorescence and singlet oxygen turn‐on. TPE‐Py‐pYK(TPP)pY tends to accumulate in ALP‐overexpressed cancer cell lysosomes as well as induce LMP and rupture of lysosomal membranes to massively evoke ICD. Such LMP‐induced ICD effectively converts immunologically cold tumors to hot as evidenced by abundant CD8+ and CD4+ T cells infiltration into the cold tumors. Exposure of ALP‐catalyzed nanoassemblies in cancer cell lysosomes to light further intensifies the processes of LMP, ICD and cold‐to‐hot tumor conversion. This work thus builds a new bridge between lysosome‐relevant cell death and cancer immunotherapy.
We report an alkaline phosphatase (ALP)‐responsive lysosomal membrane permeabilization (LMP) inducer, which can specifically accumulate in cancer cell lysosomes for evoking immunogenic cell death (ICD) and converting immunologically cold tumors into hot tumors.
Persistent luminescence without excitation light and tissue autofluorescence interference holds great promise for biological applications, but is limited by available materials with long‐wavelength ...emission and excellent clinical potential. Here, we report that porphyrin derivatives can emit near‐infrared persistent luminescence over 60 min after cessation of excitation light or on interaction with peroxynitrite. A plausible mechanism of the successive oxidation of vinylene bonds was demonstrated. A supramolecular probe with a β‐sheet structure was constructed to enhance the tumor targeting ability and the photoacoustic and persistent luminescence signals. Such probes featuring light‐triggered function transformation from photoacoustic imaging to persistent luminescence imaging permit advanced image‐guided cancer surgery. Furthermore, peroxynitrite‐activated persistent luminescence of the supramolecular probe also enables rapid and precise screening of immunogenic cell death drugs.
Porphyrin derivatives that can emit near‐infrared persistent luminescence (PL) over 60 min are reported and a mechanism for the phenomenon is proposed. The derivatives are used to synthesize supramolecular probes with peroxynitrite‐activated PL and light‐triggered imaging‐modality transformation characteristics that permit improved biological uses.
Photoacoustic (PA) imaging emerges as a promising technique for biomedical applications. The development of new strategies to boost PA conversion without depressing other properties (e.g., ...fluorescence) is highly desirable for multifunctional imaging but difficult to realize. Here, we report a new phenomenon that active intramolecular motions could promote PA signal by specifically increasing thermal‐to‐acoustic conversion efficiency. The compound with intense intramolecular motion exhibits amplified PA signal by elevating thermal‐to‐acoustic conversion, and the fluorescence also increases due to aggregation‐induced emission signature. The simultaneously high PA and fluorescence brightness of TPA‐TQ3 NPs enable precise image‐guided surgery. The preoperative fluorescence and PA imaging are capable of locating orthotopic breast tumor in a high‐contrast manner, and the intraoperative fluorescence imaging delineates tiny residual tumors. This study highlights a new design guideline of intramolecular motion amplifying PA effect.
A compound with intense intramolecular motions exhibits an amplified photoacoustic signal by specifically elevating the thermal‐to‐acoustic conversion efficiency, and the fluorescence brightness also increases due to the aggregation‐induced emission signature. Precise in vivo image‐guided cancer surgery in different stages is conducted, greatly boosting the surgery outcome.
We herein report the preparation of solid and salt‐stabilized silylzinc pivalates from the corresponding silyllithium reagents via transmetalation with Zn(OPiv)2. These resulting organosilylzinc ...pivalates show enhanced air and moisture stability and unique reactivity in the silylative difunctionalization of alkenes. Thus, a practical chelation‐assisted nickel‐catalyzed regioselective alkyl and benzylsilylation of alkenes has been developed, which provides an easy method to access alkyl silanes with broad substrate scope and wide functional group compatibility. Kinetic experiments highlight that the OPiv‐coordination is crucial to improve the reactivity of silylzinc pivalates. Furthermore, late‐stage functionalizations of druglike molecules and versatile modifications of the products illustrate the synthetical utility of this protocol.
A new type of salt‐stabilized solid silylzinc pivalate prepared from the silyllithium reagents via transmetalation with Zn(OPiv)2 is reported. These silylzinc pivalates showed enhanced air and moisture stability and unique reactivity in the nickel‐catalyzed regioselective alkyl and benzylsilylation of alkenes. Kinetic experiments highlighted the crucial involvement of OPiv‐coordination in improving the reactivity of silylzinc pivalates.
