DNA nanotechnology plays an increasingly important role in the biomedical field; however, its application in the design of organic nanomaterials is underexplored. Herein, we report the use of DNA nanotechnology to transport a NIR-II-emitting nanofluorophore across the blood–brain barrier (BBB), facilitating non-invasive imaging of brain tumors. Specifically, the DNA block copolymer, PS-b-DNA, is synthesized through a solid-phase click reaction. We demonstrate that its self-assembled structure shows exceptional cluster effects, among which BBB-crossing is the most notable. Therefore, PS-b-DNA is utilized as an amphiphilic matrix to fabricate a NIR-II nanofluorephore, which is applied in in vivo bioimaging. Accordingly, the NIR-II fluorescence signal of the DNA-based nanofluorophore localized at a glioblastoma is 3.8-fold higher than the NIR-II fluorescence signal of the PEG-based counterpart. The notably increased imaging resolution will significantly benefit the further diagnosis and therapy of brain tumors. 相似文献
Fluorescence‐guided cytoreductive surgery is one of the most promising approaches for facile elimination of tumors in situ, thereby improving prognosis. Reported herein is a simple strategy to construct a novel chainlike NIR‐II nanoprobe (APP‐Ag2S‐RGD) by self‐assembly of an amphiphilic peptide (APP) into a nanochain with subsequent chemical crosslinking of NIR‐II Ag2S QDs and the tumor‐targeting RGD peptide. This probe exhibits higher capability for cancer cell detection compared with that of RGD‐functionalized Ag2S QDs (Ag2S‐RGD) at the same concentration. Upon intraperitoneal injection, superior tumor‐to‐normal tissue signal ratio is achieved and non‐vascularized tiny tumor metastatic foci as small as about 0.2 mm in diameter could be facilely eliminated under NIR‐II fluorescent imaging guidance. These results clearly indicate the potential of this probe for fluorescence‐guided tumor staging, preoperative diagnosis, and intraoperative navigation. 相似文献
Fluorescent probes in the second near‐infrared window (NIR‐II) allow high‐resolution bioimaging with deep‐tissue penetration. However, existing NIR‐II materials often have poor signal‐to‐background ratios because of the lack of target specificity. Herein, an activatable NIR‐II nanoprobe for visualizing colorectal cancers was devised. This designed probe displays H2S‐activated ratiometric fluorescence and light‐up NIR‐II emission at 900–1300 nm. By using this activatable and target specific probe for deep‐tissue imaging of H2S‐rich colon cancer cells, accurate identification of colorectal tumors in animal models were performed. It is anticipated that the development of activatable NIR‐II probes will find widespread applications in biological and clinical systems. 相似文献
An activatable nanoprobe for imaging breast cancer metastases through near infrared‐I (NIR‐I)/NIR‐II fluorescence imaging and multispectral optoacoustic tomography (MSOT) imaging was designed. With a dihydroxanthene moiety serving as the electron donor, quinolinium as the electron acceptor and nitrobenzyloxydiphenylamino as the recognition element, the probe can specifically respond to nitroreductase and transform into an activated D‐π‐A structure with a NIR emission band extending beyond 900 nm. The activated nanoprobe exhibits NIR emission enhanced by aggregation‐induced emission (AIE) and produces strong optoacoustic signal. The nanoprobe was used to detect and image metastases from the orthotopic breast tumors to lymph nodes and then to lung in two breast cancer mouse models. Moreover, the nanoprobe can monitor the treatment efficacy during chemotherapeutic course through fluorescence and MSOT imaging. 相似文献
In vivo fluorescence imaging in the second near‐infrared window (NIR‐II) affords deep‐tissue penetration and high spatial resolution. Herein, we present a new type of Tm3+‐sensitized lanthanide nanocrystals with both excitation (1208 nm) and emission (1525 nm) located in the NIR‐II window for in vivo optical information storage and decoding. Taking advantage of the tunable fluorescence lifetimes, the optical multiplexed encoding capacity is enhanced accordingly. Micro‐devices with QR codes featuring the NIR‐II fluorescence‐lifetime multiplexed encoding were implanted into mice and were successfully decoded through time‐gated fluorescence imaging technology. 相似文献
Tumor progressions such as metastasis are complicated events that involve abnormal expression of different miRNAs and enzymes. Monitoring these biomolecules in live cells with computational DNA nanotechnology may enable discrimination of tumor progression via digital outputs. Herein, we report intracellular entropy‐driven multivalent DNA circuits to implement multi‐bit computing for simultaneous analysis of intracellular telomerase and microRNAs including miR‐21 and miR‐31. These three biomolecules can trigger respective DNA strand displacement recycling reactions for signal amplification. They are visualized by fluorescence imaging, and their signal outputs are encoded as multi‐bit binary codes for different cell types. The results can discriminate non‐tumorigenic, malignant and metastatic breast cells as well as respective tumors. This DNA computing circuit is further performed in a microfluidic chip to differentiate rare co‐cultured cells, which holds a potential for the analysis of clinical samples. 相似文献
Fluorescence imaging in the near‐infrared (NIR) region (650–900 nm) is useful for bioimaging because background autofluorescence is low and tissue penetration is high in this range. In addition, NIR fluorescence is useful as a complementary color window to green and red for multicolor imaging. Here, we compared the photoinduced electron transfer (PeT)‐mediated fluorescence quenching of silicon‐ and phosphorus‐substituted rhodamines (SiRs and PRs) in order to guide the development of improved far‐red to NIR fluorescent dyes. The results of density functional theory calculations and photophysical evaluation of a series of newly synthesized PRs confirmed that the fluorescence of PRs was more susceptible than that of SiRs to quenching via PeT. Based on this, we designed and synthesized a NIR fluorescence probe for Ca2+, CaPR‐1 , and its membrane‐permeable acetoxymethyl derivative, CaPR‐1 AM , which is distributed to the cytosol, in marked contrast to our previously reported Ca2+ far‐red to NIR fluorescence probe based on the SiR scaffold, CaSiR‐1 AM , which is mainly localized in lysosomes as well as cytosol in living cells. CaPR‐1 showed longer‐wavelength absorption and emission (up to 712 nm) than CaSiR‐1 . The new probe was able to image Ca2+ at dendrites and spines in brain slices, and should be a useful tool in neuroscience research. 相似文献
Silver nanoparticles (Ag NPs) of improved thermal stability against long‐term aggregation were prepared using the polystyrene‐b‐poly(4‐vinylpyridine)‐b‐polystyrene (PS‐b‐P4VP‐b‐PS) triblock copolymer as a multidentate ligand. First, PS‐b‐P4VP‐b‐PS was synthesized by sequential reversible addition–fragmentation transfer (RAFT) polymerization of styrene and 4‐vinylpydine using a trithiocarbonate chain transfer agent (CTA). Then Ag NPs were obtained by in situ reduction of silver nitrate using PS‐b‐P4VP‐b‐PS as a multidentate ligand. The obtained Ag NPs were stable in solution for at least 24 h while being heated at 110°C. The effect of the molar ratio of N atoms of the P4VP chain segment and AgNO3 on the stability of Ag NPs was studied, and the results suggested that Ag NPs were very stable even if the molar ratio of N atoms of the P4VP chain segment and AgNO3 was very low. This method is promising to scale up the preparation of metal NPs with good dispersibility and thermal stability, which still remains challenging. To further improve its thermal stability, 1,4‐dibromobutane was used to chemically crosslink the P4VP chain segment in solution. However, the results proved that the crosslink method is infeasible to further improve the thermal stability of Ag NPs in this system. 相似文献
Fluorescence anisotropy in the near‐infrared (NIR) spectral range is challenging because of the lack of appropriate NIR fluorescent labels. We have evaluated polymethine fluorescent dyes to identify a leading candidate for NIR anisotropy applications. The NIR dye LS601 demonstrated low fluorescence anisotropy values (r) as a result of its relatively long fluorescent lifetime 1.3 ns. The r value of LS601 unbound and coupled to biological macromolecules was found to have a sufficient dynamic range from 0.24 to 0.37, demonstrating the feasibility of fluorescence anisotropy in the NIR. The viability of fluorescence anisotropy using a NIR label was demonstrated by characterization of dye–protein conjugates. These results open the door to a number of applications in drug discovery, fluorescence anisotropy imaging and contrast agent development. 相似文献
We have rationally designed a new theranostic agent by coating near‐infrared (NIR) light‐absorbing polypyrrole (PPY) with poly(acrylic acid) (PAA), in which PAA acts as a nanoreactor and template, followed by growing small fluorescent silica nanoparticles (fSiO2 NPs) inside the PAA networks, resulting in the formation of polypyrrole@polyacrylic acid/fluorescent mesoporous silica (PPY@PAA/fmSiO2) core–shell NPs. Meanwhile, DOX‐loaded PPY@PAA/fmSiO2 NPs as pH and NIR dual‐sensitive drug delivery vehicles were employed for fluorescence imaging and chemo‐photothermal synergetic therapy in vitro and in vivo. The results demonstrate that the PPY@PAA/fmSiO2 NPs show high in vivo tumor uptake by the enhanced permeability and retention (EPR) effect after intravenous injection as revealed by in vivo fluorescence imaging, which is very helpful for visualizing the location of the tumor. Moreover, the obtained NPs inhibit tumor growth (95.6 % of tumors were eliminated) because of the combination of chemo‐photothermal therapy, which offers a synergistically improved therapeutic outcome compared with the use of either therapy alone. Therefore, the present study provides new insights into developing NIR and pH‐stimuli responsive PPY‐based multifunctional platform for cancer theranostics. 相似文献
Fluorescence probes in the NIR‐IIa region show drastically improved imaging owing to the reduced photon scattering and autofluorescence in biological tissues. Now, NIR‐IIa polymer dots (Pdots) are developed with a dual fluorescence enhancement mechanism. First, the aggregation induced emission of phenothiazine was used to reduce the nonradiative decay pathways of the polymers in condensed states. Second, fluorescence quenching was minimized by different levels of steric hindrance to further boost the fluorescence. The resulting Pdots displayed a fluorescence QY of ca. 1.7 % in aqueous solution, suggesting an enhancement of ca. 21 times in comparison with the original polymer in tetrahydrofuran (THF) solution. Small‐animal imaging by using the NIR‐IIa Pdots exhibited a remarkable improvement in penetration depth and signal to background ratio, as confirmed by through‐skull and through‐scalp fluorescent imaging of the cerebral vasculature of live mice. 相似文献
NIR light responsive nanoplatforms hold great promise for on‐demand drug release in precision cancer medicine. However, currently available systems utilize “always‐on” photothermal transducers that lack target specificity, and thus inaccurately differentiate tumors from normal tissues. Developed here is a theranostic nanoplatform featuring H2S‐mediated in situ production of NIR photothermal agents for imaging‐guided and photocontrolled drug release. The system targets H2S‐rich cancers. This nanoplatform shows H2S‐activatable NIR‐II emission and NIR light controllable release of the drug Camptothecin‐11. Upon administering the system to HCT116 tumor‐bearing mice, the tumor is greatly suppressed with minimal side effects, arising from the synergy of the cancer‐specific and NIR light activated therapy. This theranostic nanoplatform thus sheds light on precision medicine with guidance through NIR‐II imaging. 相似文献
Summary: The complexation between polystyrene‐block‐poly(acrylic acid) (PS‐b‐PAA) micelles and poly(ethylene glycol)‐block‐poly(4‐vinyl pyridine) (PEG‐b‐P4VP) is studied, and a facile strategy is proposed to prepare core‐shell‐corona micellar complexes. Micellization of PS‐b‐PAA in ethanol forms spherical core‐shell micelles with PS block as core and PAA block as shell. When PEG‐b‐P4VP is added into the core‐shell micellar solution, the P4VP block is absorbed into the core‐shell micelles to form spherical core‐shell‐corona micellar complexes with the PS block as core, the combined PAA/P4VP blocks as shell and the PEG block as corona. A model is suggested to characterize the core‐shell‐corona micellar complexes.
Schematic formation of core‐shell‐corona (CSC) micellar complexes by adsorption of PEG‐b‐P4VP into core‐shell PS‐b‐PAA micelles. 相似文献
Various fluorescence microscopy techniques require bright NIR‐emitting fluorophores with high chemical and photostability. Now, the significant performance improvement of phosphorus‐substituted rhodamine dyes (PORs) upon substitution at the 9‐position with a 2,6‐dimethoxyphenyl group is reported. The thus obtained dye PREX 710 was used to stain mitochondria in living cells, which allowed long‐term and three‐color imaging in the vis‐NIR range. Moreover, the high fluorescence longevity of PREX 710 allows tracking a dye‐labeled biomolecule by single‐molecule microscopy under physiological conditions. Deep imaging of blood vessels in mice brain has also been achieved using the bright NIR‐emitting PREX 710‐dextran conjugate. 相似文献