Jing Du

Prostate stem cell antigen antibody-conjugated multiwalled carbon nanotubes for targeted ultrasound imaging and drug delivery

Multiwalled carbon nanotubes (MWCNTs) are cut short and grafted with polyethylenimine (PEI) for further covalent conjugation to fluorescein isothiocyanate (FITC) and prostate stem cell antigen (PSCA) monoclonal antibody (mAb). The inxa0vitro and inxa0vivo toxicity data reveal that the as-prepared CNT-PEI(FITC)-mAb has good biocompatibility. Combined flow cytometry and confocal luminescence imaging experiments confirm that the CNT-PEI(FITC)-mAb can specifically target the cancer cells which overexpress PSCA. The results of inxa0vitro and inxa0vivo ultrasound (US) imaging indicate that CNT-PEI(FITC)-mAb has great potential to be used as a targeted US contrast agent. The inxa0vivo anti-cancer efficacy testing using PC-3 tumor-bearing mice as animal models demonstrates that CNT-PEI(FITC)-mAb can targetedly deliver drug to the tumors and suppress tumor growth. Findings from this study suggest that the CNT-PEI(FITC)-mAb could be used as a multifunctional platform for simultaneous US imaging and drug delivery applications.

Paramagnetic hollow silica nanospheres for in vivo targeted ultrasound and magnetic resonance imaging

A series of hollow silica nanospheres (HSNSs) with sizes ranging from 100 to 400 nm were synthesized and used for primary ultrasound imaging (US) efficiency assessment. The 400 nm HSNSs were chosen as platform for conjugation with Gd-DTPA and cyclo-arginine-glycine-aspartic acid c(RGD) peptide to construct US and magnetic resonance imaging (MRI) dual-modal contrast agents (CAs): [HSNSs@(DTPA-Gd)-RGD]. The obtained CAs displayed good physiological stability, low cytotoxicity and negligible hemolytic activity in vitro. Furthermore, the passive accumulation and active-targeting of the HSNSs in the tumor site of mice was demonstrated by US and MR imaging, respectively. The qualitative and quantitative biodistribution of the HSNSs showed that they mainly accumulated in the tissues of liver, lung, tumor after intravenous administration and then be excreted from feces. In addition, histological, hematological, blood and biochemical analysis were used to further study toxicity of the HSNSs, and all results indicated that there were no covert toxicity of HSNSs in mice after long exposure times. Findings from this study indicated that the silica-based paramagnetic HSNSs can be used as a platform for long-term targeted imaging and therapy studies safely in vivo.

Biocompatiable hollow silica microspheres as novel ultrasound contrast agents for in vivo imaging

Surface PEGylated hollow silica microspheres (PEG–HSS) of ∼1250 nm in diameter were prepared by coating a thin layer of amino functionalized silica on the template of positive charged polystyrene, removing the template in THF solution, and further coupling the HSS with methoxy polyethylene glycol propionic acid (mPEG–COOH). Cytotoxicity tests, hemolysis assays, and confocal fluorescent imaging proved that the PEG–HSS have low cytotoxicity, good blood compatibility and cell permeability. Further in vitro ultrasound imaging of the as-prepared PEG–HSS in both physiological saline solution and human blood was investigated under different imaging conditions, including different ultrasound frequencies, mechanical indexes (MIs), and different PEG–HSS concentrations, which demonstrated obvious signal enhancement. In vivo ultrasound imaging was conducted on male rats after intra-testicle injection of the PEG–HSS. These results indicate that the PEG–HSS have great potential in application as a novel ultrasound contrast agent.

The Value of Sonoelastography Scores and the Strain Ratio in Differential Diagnosis of Azoospermia

PURPOSEnWe evaluated the diagnostic performance of real-time elastography for differentiating nonobstructive from obstructive azoospermia.nnnMATERIALS AND METHODSnWe evaluated 1,192 testes, including 584 with nonobstructive azoospermia, 408 with obstructive azoospermia and 200 controls, from men with a mean ± SD age of 30 ± 5 years. Two radiologists evaluated the testes using a 5-degree elastography score system. The strain ratio was calculated on line. Of 156 azoospermic testes 78 were diagnosed by bilateral testicular biopsy for diagnostic purposes or sperm harvesting.nnnRESULTSnIn our software system a score of 3 indicated average strain, and scores 4 and 5 indicated low strain. Average or low strain (score 3 to 5) was seen in 477 of 584 testes with nonobstructive azoospermia (81.7%). This rate was significantly higher than the rate in obstructive azoospermic and control testes (68 of 408 or 16.3% and 30 of 200 or 15.0%, p <0.001). The strain ratio significantly differed for nonobstructive and obstructive azoospermia (median 0.490 and 0.340, Z = -20.560, p <0.001).nnnCONCLUSIONSnReal-time elastography is a promising imaging method with great potential for the differential diagnosis of azoospermia.

Synthesis, characterization, and in vitro evaluation of targeted gold nanoshelled poly(d,l-lactide-co-glycolide) nanoparticles carrying anti p53 antibody as a theranostic agent for ultrasound contrast imaging and photothermal therapy

Abstract Breast cancer is the leading cause of cancer-related deaths in women and earlier detection can substantially reduce deaths from breast cancer. Polymers with targeted ligands are widely used in the field of molecular ultrasound imaging and targeted tumor therapy. In our study, the nanotheranostic agent was fabricated through filling perfluoropropane (C3F8) into poly(d,l-lactic-co-glycolic acid) nanoparticles (PLGA NPs), followed by the formation of gold nanoshell on the surface, then conjugated with anti p53 antibody which has high specificity with the p53 protein overexpressing in breast cancer. The average diameter of the gold nanoshelled PLGA NPs carrying anti p53 antibody (p53-PLGA@Au NPs) was 247 ± 108.2 nm. The p53-PLGA@Au NPs had well-defined spherical morphology and hollow interiors observed by electron microscope, and had a good photothermal effect under the irradiation of an 808 nm laser. The results of laser scanning confocal microscope (LSCM) and flow cytometer (FCM) indicated the specific targeting of p53-PLGA@Au NPs conjugating with breast cancer MCF-7 cells overexpressing p53 protein in vitro. Also the ultrasound imaging experiments in vitro showed that p53-PLGA@Au NPs were suitable for ultrasound contrast imaging. In conclusion, the p53-PLGA@Au NPs are demonstrated to be novel targeted UCAs and may have potential applications in the early diagnosis and targeted near-infrared (NIR) photothermal therapy of breast cancer in the future.

Synthesis, characterization and in vitro and in vivo investigation of C3F8-filled poly(lactic-co-glycolic acid) nanoparticles as an ultrasound contrast agent

The present study aimed to prepare perfluoropropane (C3F8)-filled poly(lactic-co-glycolic acid) (PLGA) nanoparticles and investigate the feasibility of using PLGA nanoparticles as an ultrasound contrast agent. The PLGA nanoscale ultrasound contrast agent was prepared using a modified double-emulsion solvent evaporation method. Camphor in the form of a sublimable porogen was added to render the nanoparticles hollow and enable C3F8 gas introduction. Various physicochemical properties of PLGA nanoparticles, including morphology, size and dispersion, were analyzed by electron microscopy and dynamic laser scattering. In vitro ultrasound imaging of C3F8-filled PLGA nanoparticles was also investigated under various imaging conditions. Further in vivo ultrasound imaging was conducted on male rats following intratesticular injection of PLGA nanoparticles. C3F8-filled PLGA nanoparticles with a mean diameter of 152.0±58.08 nm were obtained. Electron microscopy revealed spherical-shaped nanoparticles with smooth surfaces, a capsular morphology and a large hollow within. In vitro ultrasound imaging of hollow PLGA nanoparticles indicated marked signal enhancement. Local intensity of the acoustical signal continued to increase during PLGA-nanoparticle injection into the testicle and the ability of hollow PLGA nanoparticles to enhance ultrasound imaging in vivo was demonstrated. The enhancement image of testicular tissue following injection with C3F8-filled PLGA nanoparticles was sustained for a minimum of five minutes. In conclusion, the hollow C3F8-filled PLGA nanoparticles were demonstrated to have potential for applications as a novel ultrasound contrast agent.

Preparation of pH-responsive hollow poly(MAA-co-EGDMA) nanocapsules for drug delivery and ultrasound imaging

pH-Responsive hollow poly(MAA-co-EGDMA) (abbreviated as HPMAA) copolymer nanocapsules with uniform core size of ∼250 nm and flexible shell thickness of ∼17 nm were synthesized by a hard-template protocol that combined a sol–gel process and surface-initialized polymerization. The silica template was then removed in a 10% HF solution. After further partial surface modification the HPMAA with biocompatible methoxypolyethylene glycol amine (mPEG2000-NH2) and the HPMAA–mPEG nanocapsules displayed negligible hemolytic activity and low cytotoxicity that could be used for pH-responsive delivery of drug (doxorubicin: DOX) and ultrasound imaging. The HPMAA–mPEG nanocapsules have high DOX-loading content (52.4 wt%). The DOX-loaded nanocapsules can be efficiently internalized by cells and controlled release within 20 h under high pH (7.4) condition, resulting substantial inhibition of HeLa cells. Then, the real-time in vivo ultrasound imaging of mice demonstrated that the HPMAA–mPEG nanocapsules can also be used as a novel ultrasound imaging contrast agent.

Au-poly(lactic-co-glycolic) acid complex nanoparticles as ultrasound contrast agents: Preparation, characterization and in vitro study

The present study aimed to prepare and characterize an Au-poly(lactic-co-glycolic) acid (PLGA) complex, surfaced with gold nanoparticles (GNPs), and to assess its use as an ultrasound contrast agent for inxa0vitro imaging. PLGA nanoparticles (NPs) were prepared by a modified double‑emulsion solvent evaporation method. GNPs were prepared via reduction with sodium citrate. Au‑PLGA complexes were created through the binding of polyethylene glycosylated GNPs to the surface of PLGA NPs. Various physical characteristics of PLGA NPs, GNPs and Au‑PLGA complexes, including morphology, size, dispersion, ζ potential and stability were observed and measured. The study of the inxa0vitro imaging capability of the Au‑PLGA complex was conducted by setting multi‑parameter imaging conditions. The average sizes of PLGA NPs, GNPs and the Au‑PLGA complex were 144.5±30.28, 21.42±1.56 and 359.4±67.94xa0nm, respectively. Transmission electron microscopy (TEM) revealed that PLGA NPs and GNPs were spherically shaped, but GNPs had smooth surface while PLGA NPs had a capsular morphology with a wrinkled surface and large voids. The maximum absorption peak of 20xa0nm GNPs was 508xa0nm while that of the Au‑PLGA complex was 515xa0nm on an ultraviolet‑visible absorption spectrum curve. The results of TEM and the redshift spectrum demonstrated that GNPs successfully bound to the surface of the PLGA NPs. The complex demonstrated good stability and its size changed little over time. Inxa0vitro imaging experiments revealed that the Au‑PLGA complex had a good imaging ability. The present study demonstrated that the Au‑PLGA complex is a promising novel ultrasound contrast agent.

Preparation and Imaging Investigation of Dual-targeted C 3 F 8 -filled PLGA Nanobubbles as a Novel Ultrasound Contrast Agent for Breast Cancer

Molecularly-targeted contrast enhanced ultrasound (US) imaging is a promising imaging strategy with large potential for improving diagnostic accuracy of conventional US imaging in breast cancer detection. Therefore, we constructed a novel dual-targeted nanosized US contrast agent (UCA) directed at both vascular endothelial growth factor receptor 2 (VEGFR2) and human epidermal growth factor receptor 2 (HER2) based on perfluoropropane (C3F8)-filled poly(lactic-co-glycolic acid) (PLGA) (NBs) for breast cancer detection. In vitro, single- or dual-targeted PLGA NBs showed high target specificities and better effects of target enhancement in VEGFR2 or HER2-positive cells. In vivo, US imaging signal in the murine breast cancer model was significantly higher (Pu2009<u20090.01) for dual-targeted NBs than single-targeted and non-targeted NBs. Small animal fluorescence imaging further confirmed the special affinity of the dual-targeted nanosized contrast agent to both VEGFR2 and HER2. Immunofluorescence and immunohistochemistry staining confirmed the expressions of VEGFR2 and HER2 on tumor neovasculature and tumor cells of breast cancer. In conclusions, the feasibility of using dual-targeted PLGA NBs to enhance ultrasonic images is demonstrated in vitro and in vivo. This may be a promising approach to target biomarkers of breast cancer for two site-specific US molecular imaging.

The in vitro study of Her-2 targeted gold nanoshell liquid fluorocarbon poly lactic-co-glycolic acid ultrasound microcapsule for ultrasound imaging and breast tumor photothermal therapy

Abstract Antibody-mediated targeting therapy has been successful in treating patients with breast cancer by improving the specificity and clinical efficacy. In this study, we constructed the human epidermal growth factor receptor-2 (Her2) antibody-conjugated ultrasound contrast agent with lactic-co-glycolic acid (PLGA) as film forming and perfluorocty bromide (PFOB) as internal material, which was coated by gold nanoshell (Her2-PFOB@PLGA@Au), to realize the integration of diagnosis and treatment. The contrast agent was spherical, with the diameter was 256.8 ± 53.4 nm, and had a good dispersion; Ultrasound imaging experiments in vitro showed that the gold nanoshell polylactic acid microcapsule was suitable for ultrasound contrast imaging with the exquisite and uniform dot intensive high echo. The agent had a great photothermal effect under the near-infrared (NIR) with no obvious biological toxicity for both Her2-positive and negative tumor cells; Moreover, both the results of laser scanning confocal microscope (LSCM) and flow cytometer (FCM) demonstrated the great specificity of Her2-PFOB@PLGA@Au conjugating with Her2 positive breast cancer cells (SKBR3). In conclusion, the successful synthesis of the Her2-PFOB@PLGA@Au microcapsule, offered a new therapeutic strategy of combining diagnosis with therapy for fighting against the breast cancer.