The effect of pH transition points of ultra-pH sensitive fluorescent nanoprobes on tumor imaging efficiency / 药学学报

During fluorescence-guided cancer surgery, ultra-pH sensitive (UPS) fluorescent nanoprobes has multiple advantages such as real-time imaging procedures, ultra-high imaging sensitivity as well as broad tumor detection specificity. UPS nanoprobes stay at "OFF" state at higher pH and turn into "ON" state at lower pH with emission of strong fluorescence. Moreover, the transition pH points (transition pH point, pHt) can be precisely controlled by structural-based strategy. One of the previously-reported UPS nanoprobes showed good imaging effect. However, it is still not clear about the effect of pHt on cancer imaging efficiency of UPS nanoprobes and to further identify the optimal UPS. In this study, we synthesized a series of UPS nanoprobes with pHt at 4.5, 6.2, 6.6, 7.8 by adjusting the hydrophobic blocks of UPS polymers. Each nanoprobe showed excellent stability in "OFF" state by dynamic light scattering and uniform morphology observed by transmission electron microscopy. In vitro imaging characterized the ultra-pH sensitive fluorescence transition of each probe. In vivo imaging results identified two UPS nanoprobes (NP-6.2 and NP-6.6) with superior tumor imaging effect. All animal experiments in this study were approved by the Animal Ethics Committee of Peking University Health Science Center and were strictly followed by the welfare regulations of laboratory animals of Peking University Health Science Center. Therefore, this study has explored the effect of pHt on the cancer imaging efficiency of UPS nanoprobes and provides a new idea for design of the other cancer microenvironment-responsive polymers.

Super-sensitive bifunctional nanoprobe: Self-assembly of peptide-driven nanoparticles demonstrating tumor fluorescence imaging and therapy

The development of nanomedicine has recently achieved several breakthroughs in the field of cancer treatment; however, biocompatibility and targeted penetration of these nanomaterials remain as limitations, which lead to serious side effects and significantly narrow the scope of their application. The self-assembly of intermediate filaments with arginine-glycine-aspartate (RGD) peptide (RGD-IFP) was triggered by the hydrophobic cationic molecule 7-amino actinomycin D (7-AAD) to synthesize a bifunctional nanoparticle that could serve as a fluorescent imaging probe to visualize tumor treatment. The designed RGD-IFP peptide possessed the ability to encapsulate 7-AAD molecules through the formation of hydrogen bonds and hydrophobic interactions by a one-step method. This fluorescent nanoprobe with RGD peptide could be targeted for delivery into tumor cells and released in acidic environments such as endosomes/lysosomes, ultimately inducing cytotoxicity by arresting tumor cell cycling with inserted DNA. It is noteworthy that the RGD-IFP/7-AAD nanoprobe tail-vein injection approach demonstrated not only high tumor-targeted imaging potential, but also potent antitumor therapeutic effects in vivo. The proposed strategy may be used in peptide-driven bifunctional nanoparticles for precise imaging and cancer therapy.

Research progress of MR nanoprobers in targeting oral squamous cell carcinoma / 中国介入影像与治疗学

For analyzing the migration ability of oral squamous cell carcinoma (OSCC) cells in vivo, invasive methods were often used in the past. The experimental animals would be executed within a certain period of time after cell transplantation, and the oral and maxillofacial tissues should be analyzed with pathological section. These method can not be used to observe the migration and proliferation of OSCC cells dynamically in the same experimental animal in vivo. With the development of non-invasive methods in recent years, the highly specific protein expressed in OSCC cells can be labeled with MR technology using nanoparticles as contrast agent, thus to target and trace the metastasis in vivo, and to speculate the specific stages of OSCC. The advancements of targeting and tracing OSCC with MR nanomolecular probes were reviewed in this article.

Recent developments in multimodality fluorescence imaging probes

Multimodality optical imaging probes have emerged as powerful tools that improve detection sensitivity and accuracy, important in disease diagnosis and treatment. In this review, we focus on recent developments of optical fluorescence imaging (OFI) probe integration with other imaging modalities such as X-ray computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), single-photon emission computed tomography (SPECT), and photoacoustic imaging (PAI). The imaging technologies are briefly described in order to introduce the strengths and limitations of each techniques and the need for further multimodality optical imaging probe development. The emphasis of this account is placed on how design strategies are currently implemented to afford physicochemically and biologically compatible multimodality optical fluorescence imaging probes. We also present studies that overcame intrinsic disadvantages of each imaging technique by multimodality approach with improved detection sensitivity and accuracy.

Application progresses of optical molecular imaging techniques in cancer / 中国医学影像技术

The molecular imaging technology is a kind of imaging technology which displays the microstructure of tissue,cell and sub cellular level in vivo.It has the characteristics of real time,noninvasive,accurate and sensitive,and can be used for early screening and diagnosis of tumor at the cellular and molecular level.Following the development of bioluminescence and fluorescence imaging,optical molecular imaging technology is making rapidly progression.The application of optical molecular imaging technology in cancer was reviewed in the paper.

Detection of nucleic acid sequence-based amplification products by gold nanoprobe-based solution hybridization for the diagnosis of invasive aspergillosis / 临床检验杂志

Objective To establish a method of gold nanoprobe-based solution hybridization (GNBSH) to detect nucleic acid sequence-based amplification (NASBA) products for the rapid diagnosis of invasive aspergillosis (IA).Methods The Aspergillus specific 18S rRNA was amplified by NASBA and then the amplified products were hybridized with the gold nanoprobes which were modified with thiol compounds at the 5'end.Serum samples from 106 patients,including 14 with a definite IA,32 with suspected IA and 60 without IA,were detected by the established method,and the obtained results were compared with that of galactomannan (GM) test to evaluate its accuracy.Results The gold nanoprobes only hybridized with Aspergillus NASBA products but not other non-Aspergillus strains.The sensitivity,specificity and the area under the ROC curve (AUCROC) of the established GNBSH method for detecting 106 clinical samples were 82.61％ (38/46),81.67％ (49/60) and 0.890,respectively.The sensitivity,specificity and AUCROC of GM test were 56.52％ (26/46),83.33％ (50/60) and 0.723,respectively.Conclusion The established GNBSH method to detect Aspergillus NASBA products has high sensitivity and specificity and simple operation,which may be used to detect the infection of Aspergillus by clinical laboratories.

Preparation of a new bio-navigation nanoprobe used for prostate cancer cell detection in vitro / 第二军医大学学报

Objective To prepare a granulocyte targeting-mediated magnetic-fluorescent nanoprobe for detecting prostate cancer PC3 cells in vitro. Methods The nanometer materials with magnetic and red fluorescence, which were prepared using Fe3O4 as the core, and SiO2 and rhodamine isothiocyanate as the shell, were mixed with normal human peripheral blood granulocytes in different proportions, and co incubated for different periods to examine the toxicity of nanometer materials to granulocytes. The best proportion was selected to combine the nanometer materials and granulocytes in vitro. Finally we obtained the granulocyte targeting-mediated magnetic-fluorescent nanoprobes. We mixed PC3 cells and normal human whole blood cells in different proportions, added the nanoprobes, and then observed the targeting situation of the nanoprobes under a fluorescence microscope. Results The nanoprobe had no obvious influence on the survival rate of granulocytes at different concentrations and action times set in this study. The nanoprobes were enriched around the PC3 cells with a “petal-like” structure, but the peripheral blood cells were not enriched by probes. Conclusion The magnetic-fluorescent nanometer materials prepared in this study have no toxicity to granulocytes, and it can effectively detect tumor cells by the biological targeting effect of granulocytes on tumor cells.

In vitro study on mesothelin antibody-tagged nanoprobe targeting human pancreatic cell line BxPC3 / 中华胰腺病杂志

Objective To observe the targeted function of a mesothelin antibody modified nanoprobe in human pancreatic cancer BxPC3 cell.Methods The Fe3O4@SiO2 nanoprobe was prepared by St(o)ber method,and then quantum dots (CdTe) and mesothelin antibody was crosslinked to obtain the properties of targeting and fluorescent.Fluorescent nano Fe3O4@SiO2 probes and BxPC3 cells were incubated in vitro for 30 min.Its targeting performance was tested by the CCD imaging system and magnetic separation technology.HepG-2 and K562 cells with low expression of mesothelin were selected as reference cells.Results This preparation method of nanoprobe could produce a uniform and narrow distribution particle with particle size mainly ranging from 120 to 140 nm.The cell adsorption experiments showed that the adsorption efficiency of BxPC3,HepG-2 and K562 by nanoprobe without crosslinking antibody were less than 20％,as a non-specific adsorption; and the adsorption efficiency of BxPC3,HepG-2 and K562 by crosslinking mesothelin antibody nanoprobe were (53.9 ± 1.8) ％,(8.0 ± 2.1) ％ and (8.9 ± 2.3) ％ respectively,and the adsorption capacity with BxPC3 was significantly increased.Conclusions The nanoprobe modified by mesothelin antibody can effectively recognize BxPC3 cells which highly expressing mesothelin.

Synthesis of the PLA-PEG-PLL gadolinium loaded nanoprobe targeted to vascular endothelial growth factor used for the molecular imaging of micro-hepatic carcinoma / 中华肝胆外科杂志

Objective This study aims to synthesize a novel gadolinium loaded nanoprobe targeted to vascular endothelial growth factor (VEGF) and assess its clinical value for imaging micro hepatic carcinoma.Methods A carrier was made by the biocompatible polymer material polylactic acid-polyethylene glycol-poly-L-lysinenanoparticles (PLA-PEG-PLLs).The targeted nanoprobe was obtained with anti-VEGF antibody and gadolinium (Gd) bonding to the surface of the carrier.MRI in vitro determined the T1 relaxivity of the nanoprobe.A live cancer model enhanced MR scan was performed by injecting targeted nanoprobes into the tail vein of grafted H22 tumor mice.The enhanced characteristics of the subcutaneous tumors and micro-heatic carcinoma were then reviewed.Results The particle size of the VEGF-targeted PLA-PEG-PLL gadolinium loaded nanoprobe was 85.8±7.2 nm with a zeta potential of 21.63±2.4 mV.The R1 relaxivity of the targeted nanoprobe was 18.394 mmol/s at 3.0 T when its gadolinium concentration was 8.0 μmol/ml.The enhanced MR scan using targeted probes showed that the big and micro-subcutaneous cancer exhibited a specifically delayed enhancement with an enhanced peak value at 2 or 3 hours,rather than the enhancement of the tumor using the nontargeted nanoparticles.Conclusion In conclusion,the VEGF targeted PLA-PEG-PLL gadolinium loaded nanoprobe was synthesized successfully,showed a high relaxivity,achieved targeted imaging of the micro-hepatic carcinoma,and exhibits a promising potential in the detection of this liver cancer.

Preparation of human malignant melanoma ganglioside ScFv antibody-conjugated quantum dot nanoprobe and its specific binding with human malignant melanoma cells / 中国肿瘤生物治疗杂志

Objective: To prepare a nanoprobe, anti-human melanoma ganglioside single chain variable fragment (GD/ScFvMEL) antibody conjugated with CdTe quantum dot, and to observe its ability to specifically bind human malignant melanoma cells. Methods: The GD/ScFvMEL gene was cloned into pET32a (+), and the plasmid was then transformed into E. coli BL21 (DE3) for GD/ScFvMEL protein antibody expression. The expressed GD/ScFvMEL antibody was purified by denaturing method and further refolded by modified dialysis method. The purified GD/ScFvMEL antibody was analyzed by SDS-PAGE. The GD/ScFvMEL-QDs nanoprobe was prepared by conjugating GD/ScFvMEL antibody with CdTe quantum dot, and its specificity was observed by incubating with MGC-803 cells and melanoma A375 cells. Results: The recombinant pET32a-GD/ScFvMEL was constructed and confirmed by PCR, restriction endonuclease analysis and DNA sequencing. The proportion of expressed GD/ScFvMEL antibody in total bacteria proteins was about 40% as detected by SDS-PAGE. The purified- and refolded-GD/ScFvMEL antibody was effectively conjugated with CdTe quantum dot, and the resulting GD/ScFvMEL-QDs nanoprobe was successfully prepared. The GD/ScFvMEL-QDs nanoprobe could specifically bind melanoma A375 cells, but could not bind stomach cancer MGC-803 cells. Conclusion: We have successfully prepared an anti-human melanoma ganglioside single-chain antibody-CdTe quantum dot nanoprobe, which can specifically bind melanoma cells.