Target-Triggered Nanoprobes: Fabrication, Cell Imaging And Tumor Therapy

Cancer is a serious threat to human health,which caused by cell malignant division and proliferation regulation.Nowadays,the main therapies against cancer are chemical drug therapy,radiation therapy and surgery.However,some of these methods are harm to the human body with side effects.Make the matter worse,some methods are not effective for specific cancer types.In order to solve these problems,a variety of merging technologies including the analysis and early diagnosis of cancer biomarkers,optical therapy,immune therapy and gene therapy have been developed for tumor theranostics.Specifically,optical therapy against tumors possesses good tolerability,slight side effects to human body and displays the great potential in biology and clinical.Here,we developed several fluorescent strategies for cancer diagnosis and target-triggered enhanced optical therapy via constructing novel multifunctional nanoprobe by taking advantage of the diversity and property of nanomaterials.It includes the following sections:1.MicroRNA-responsive cancer cell imaging and therapy with functionalized gold nanoprobeIntegration of cancer cell imaging and therapy is critical to enhance the theranostic efficacy and prevent the under-or over-treatment.Here,a multifunctional gold nanoprobe is designed for simultaneous miRNA-responsive fluorescence imaging and therapeutic monitoring of cancer.By assembling with folic acid as the targeted moiety and a dye-labelled molecular beacon(MB)as the recognition element and signal switch,the gold nanoprobe is folate receptor-targeted delivered into the cancer cells and the fluorescence is lighted with the unfolding of MB by intracellular microRNA(miRNA),resulting in an efficient method for imaging and detection of nucleic acid.The average quantity of miRNA-21 is measured to be 1.68 pg in a single HeLa cell.Upon the near-infrared irradiation at 808 nm,the real-time monitoring and assessing of photothermal therapeutic efficacy is achieved from the further enhanced fluorescence of the dye labeled to MB,caused by the high photothermal transformation efficiency of the gold nanocarrier to unwind the remaining folded MB and depart the dye from the nanocarrier.The fluorescence monitoring is also feasible for applications in vivo.This work provides a simple but powerful protocol with great potential in cancer imaging,therapy and therapeutic monitoring.2.Sensitive detection of intracellular microRNA based on a flowerlike vector with catalytic hairpin assemblyTracking the intracellular microRNAs(miRNAs)in quite low abundance is a critical challenge for the understanding of early diagnosis and gene drug selection.Here,a flowerlike nanovector is developed for fluorescence imaging and detection of miRNA in live cells with catalytic hairpin assembly.The nanovector was prepared by in-situ polymerization of an ultrathin polyldopamine on gold nanoflower,and following by noncovalent assembly with folic acid as the targeted moiety and dye labelled hairpin DNA 1(HI)and hairpin DNA 2(H2)as the recognition and amplification elements.The loading efficiency of the vector toward hairpin DNA improves 1.6 fold than that of gold nanoparticles owing to the unique horn structure.Once the nanovector delivered into cells via folate receptor-targeted endocytosis,miRNA-21 as the initiator could unfold the H1 loaded on the horn to obtain H1-target duplex,and the latter with exposing sticky end is dissociated by H2 via strand-displacement to release the target for the next cycle,leading to a catalytic hairpin assembly amplification approach for fluorescence imaging and sensitive detection of microRNAs.The quantity of miRNA-21 is measured to be 1.65 pg in an average single HeLa cell.This horned vector provides a powerful platform for multiple signal outputs and has the potential applications in trace detection of intracellular biomolecules.3.Multifunctional metal-organic framework nanoprobe for cathepsin B-activated cancer cell imaging and chemo-photodynamic therapyIntegration of a photodynamic therapy platform with a drug-delivery system in a porous structure is an urgent challenge for enhanced anticancer therapy.Here,an amino-functionalized metal-organic framework(MOF),which is useful as efficient delivery vehicle for drugs and provides the-NH2 group for postsynthetic modification,is chosen and well designed for cell imaging and chemo-photodynamic therapy.The multifunctional MOF nanoprobe was firstly assembled with camptothecine drug via noncovalent encapsulation,and then bound with folic acid as the targeted element and chlorine e6(Ce6)-labelled CaB substrate peptide as the recognition moiety and signal switch.The designed MOF probe can realize cathepsin B-activated cancer cell imaging and chemo-photodynamic dual-therapy combining Ce6 as the photosensitizer and the camptothecine drug.Compared with the individual treatment,the dual-functional nanoprobe presents an enhanced treatment efficiency in terms of the time of chemotherapy,laser power and irradiation time of the photodynamic therapy,which has been confirmed in cancer cells and in vivo assays.This work presents a significant example of the MOF nanoprobe as an intracellular switch,and shows great potential in cancer-cells targeted imaging and multiple therapies.4.Dual-triggered oxygen self-supply black phosphorus nanosystem for enhanced photodynamic therapyNonspecific distribution of photosensitizer and the intrinsic hypoxic condition in the tumor microenvironment are two key factors limiting the efficacy of O2-dependent photodynamic therapy(PDT).Herein,a dual-triggered oxygen self-supported nanosystem using black phosphorus nanosheet(BPNS)as both photosensitizer and nanocarrier was developed to enhance PDT for tumors within hypoxic microenvironment.The BPNS platform was functionalized with folate and a blocker DNA duplex of 5'-Cy5-aptamer-heme/3'-heme labeled oligonucleotides.The resulting heme dimer could passivate its peroxidase activity.After specific recognition of aptamer-target,the quenched fluorescence is "turned" on by cellular adenosine triphosphate.The passivated nanosystem then activates the catalytic function towards excessive intracellular H2O2 to generate O2 essential to sustain BPNS-mediated PDT,leading to an 8.7-fold and 7.5-fold increase of PDT efficacy in treating the hypoxic cells and tumor,respectively.Therefore,the dual-triggered oxygen self-supply nanosystem not only exerts tumor microenvironment-associated stimulus for enhanced PDT but also surmounts hypoxia-associated therapy resistance.5.A black phosphorus/manganese dioxide nanoplatform:oxygen self-supply monitoring,photodynamic therapy enhancement and feedbackOvercoming the hypoxic condition in tumor issues is an important task for improving O2-dependent photodynamic therapy(PDT)efficiency.To date,few researches have been reported on selecting the timing of laser treatment by monitoring the oxygen self-supply process.Here,a black phosphorus-based strategy was developed for dual-mode monitoring oxygen self-supply,enhancing photodynamic therapy against hypoxic tumors,and feeding back therapeutic effect.The hybridized nanoplatform(R-MnO2-FBP)was prepared by assembly of Rhodamine B(RhB)-encapsulated manganese dioxide(R-MnO2)as the O2 supplier and indicator,and fluorescein isothiocyanate(FITC)-labelled peptide-functionalized black phosphorus as the theranostic agent.The time-dependent assays suggested that the O2 release was proportional to the liberation of Mn2+ and RhB in the R-MnO2-FBP system.After specific delivery into cancer cells,R-MnO2-FBP not only dissociated in the acidic and H2O2-rich environment and generated oxygen to overcome hypoxia-associated PDT resistance,but also released Mn2+and RhB dye simultaneously,leading to dual-mode(magnetic resonance imaging/fluorescence imaging)monitoring of the oxygen self-supply process.More significantly,the imaging-guided oxygen-evolving PDT in hypoxic cells displayed 51.6%cell apoptosis in PDT efficacy than that without optimizing,which could also be confirmed by the FITC fluorescence recovery induced by the activated caspase-3 in the apoptotic cells.In vivo photonic therapy by R-MnO2-FBP further demonstrated the ability of R-MnO2-FBP to choose the timing of laser application with dual-mode self-feedback.Therefore,the designed oxygen self-supply nanocomplex not only exerts tumor microenvironment-associated stimulus for enhanced PDT but also provides a new idea about monitoring the enhanced PDT process including oxygen supply and therapeutic effect.6.Black phosphorus/metal organic framework for enhanced photodynamic therapy and caspase-responsive theranostics.The photooxidation and instability of black phosphorus limited the application of black phosphorus as photothermal therapy(PTT)and photodynamic therapy agent.In this work,the black phosphorous quantum dot(BPQD)and catalase were in-situ capsuled by metal-organic framework with-NH2 group for postsynthetic modification to form BQC-MOF.Then,the complex was functionalized by Cy3-labelled caspase substrate peptide as signal switch for self-monitoring the efficacy of oxygen evolving PDT/PTT to form BQC-fMOF.The resulted nanoprobe significantly increased the singlet oxygen quantum yield of BPQD due to the outer MOF sensitization.In addition,the catalase encapsulated in the MOF could maintain a high catalytic activity towards H2O2 to produce oxygen that can supply PDT in the cell microenvironment owing to the protection of the outer MOF.Meanwhile,the probe showed a high photothermal transtreatment effect and realized the oxygen self-supply PDT/PTT synergistic therapy.Under 660/808 nm laser radiation,the resulted probe(BQC-fMOF)induced cell apoptosis and the caspase was activated,leading the cleavage of its corresponding substrate peptide and the fluorescence recovery of the quenched Cy3 for the real-time monitoring of curative effect.Therefore,the designed BQC-fMOF can effectively induce apoptosis by the PDT/PTT synergistic therapy,and provides a new idea about the applications of black phosphorous materials in theranostics.