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1.
Theranostics ; 10(6): 2791-2802, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32194835

RESUMO

Development of unique theranostic nanoplatforms for tumor imaging and therapy remains an active topic in current nanomedicine. Here, we designed a novel targeted theranostic nanoplatform for enhanced T1 -weighted magnetic resonance (MR) imaging-guided chemotherapy by constructing layered double hydroxide (LDH)-stabilized ultrasmall iron oxide (Fe3O4) nanoparticles with hyaluronic acid (HA) modified as targeting agents, and anticancer drug doxorubicin (DOX) loaded with a high loading efficiency. Methods: The structure and release property of LDH-Fe3O4-HA/DOX nanoplatforms were characterized systematically. B16 melanoma cells with CD44 receptors overexpressed were used as model cells to determine the biocompatibility, targeting capability, and therapeutic efficiency of nanoplatforms. For in vivo experiment, hyaluronidase (HAase) pretreatment was combined with nanoplatform administration to investigate the MR imaging and chemotherapeutic effect. Results: The LDH-Fe3O4-HA nanohybrids possess good colloidal stability and cytocompatibility, display an r1 relaxivity 10-fold higher than the pristine ultrasmall Fe3O4 (4.38 mM-1 s-1 vs 0.42 mM-1 s-1), and could release drug in a pH-responsive manner. In vitro experiments demonstrate that LDH-Fe3O4-HA/DOX nanohybrids are able to specifically target B16 cells overexpressing CD44 receptors and effectively release DOX to nucleus. In vivo results show that with the pretreatment of tumor tissue by HAase to degrade the overexpressed HA in extra-cellular matrix, the designed nanoplatforms have a better tumor penetration for significantly enhanced MR imaging of tumors and tumor chemotherapy with low side effects. Conclusion: The designed LDH-Fe3O4-HA/DOX nanohybrids may be developed as a novel targeted theranostic nanoplatform for enhanced T1 -weighted MR imaging-guided chemotherapy of CD44 receptor-overexpressing tumors.

2.
Bioconjug Chem ; 31(3): 907-915, 2020 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-32096990

RESUMO

Development of versatile nanoplatforms for cancer theranostics remains a hot topic in the area of nanomedicine. We report here a general approach to create polyethylenimine (PEI)-based hybrid nanogels (NGs) incorporated with ultrasmall iron oxide (Fe3O4) nanoparticles (NPs) and doxorubicin for T1-weighted MR imaging-guided chemotherapy of tumors. In this study, PEI NGs were first prepared using an inverse emulsion approach along with Michael addition reaction to cross-link the NGs, modified with citric acid-stabilized ultrasmall Fe3O4 NPs through 1-ethyl-3-(3-(dimethylamino)propyl) carbodiimide hydrochloride (EDC) coupling, and physically loaded with anticancer drug doxorubicin (DOX). The formed hybrid NGs possess good water dispersibility and colloidal stability, excellent DOX loading efficiency (51.4%), pH-dependent release profile of DOX with an accelerated release rate under acidic pH, and much higher r1 relaxivity (2.29 mM-1 s-1) than free ultrasmall Fe3O4 NPs (1.15 mM-1 s-1). In addition, in contrast to the drug-free NGs that possess good cytocompatibility, the DOX-loaded hybrid NGs display appreciable therapeutic activity and can be taken up by cancer cells in vitro. With these properties, the developed hybrid NGs enabled effective inhibition of tumor growth under the guidance of T1-weighted MR imaging. The developed hybrid NGs may be applied as a versatile nanoplatform for MR imaging-guided chemotherapy of tumors.

3.
Macromol Biosci ; 20(2): e1900282, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31829523

RESUMO

Nuclear medicine, involving nuclear medicine imaging and radiotherapy (RT), has become a mainstay of theranostics in the field of nanomedicine and several examples have been successfully translated into clinical practice. The combination of radionuclides with dendrimers has long been investigated in nuclear imaging, such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT), providing functional information for whole body quantitative analysis with high sensitivity due to the unique structural advantages of the dendrimer platform. Besides, radioisotopes with both therapeutic and imaging functionalities can also be combined with dendrimer platforms for theranostic applications. In this review, the recent advances in the development of radionuclide-labeled poly(amidoamine) dendrimer-based nanodevices for targeted PET, SPECT, SPECT/computed tomography, SPECT/magnetic resonance imaging of tumors, RT, as well as for SPECT-imaging-guided RT of cancer are summarized. Current restrictions hindering the clinical translation of dendrimer-based nuclear nanodevices and future prospects are also discussed.

4.
J Insect Sci ; 19(6)2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31830272

RESUMO

The sycamore lace bug, Corythucha ciliata (Say) is an invasive pest infesting trees of the genus Platanus. Both adults and nymphs damage the foliage of sycamore trees. Nymphs cannot survive in low temperatures; however, the sycamore lace bug overwinters as adults. In this study, we analyzed the metabolite profiles of this pest to determine significantly regulated metabolites during paurometabolous development from nymphs to adults. The identification of metabolites is essential to convert analytical data into meaningful biological knowledge. A total of 62 metabolites were identified using GC-MS. Among them, 29 different metabolites showed differences in content among nymphs, adult females (AF), and adult males (AM). Five of the 29 metabolites, including caffeic acid, D-glucose, D-mannose, glycerol and aminooxyacetic acid, were significantly increased and nine of them were significantly decreased during the developmental stages from nymph to adult. In addition, we identified three novel aldo-keto reductase (AKR) genes that may play a significant role in the control of glycerol biosynthesis. Moreover, the characteristics and expression levels of these genes were analyzed. This study will provide us with the necessary information to improve our understanding of the changes in metabolites in C. ciliata during paurometabolous development.


Assuntos
Aldo-Ceto Redutases/metabolismo , Hemípteros/metabolismo , Metamorfose Biológica , Animais , Feminino , Hemípteros/genética , Hemípteros/crescimento & desenvolvimento , Masculino , Filogenia
5.
Sci Rep ; 9(1): 17143, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31748535

RESUMO

The development of machine vision-based technologies to replace human labor for rapid and exact detection of agricultural product quality has received extensive attention. In this study, we describe a low-rank representation of jointly multi-modal bag-of-feature (JMBoF) classification framework for inspecting the appearance quality of postharvest dry soybean seeds. Two categories of speeded-up robust features and spatial layout of L*a*b* color features are extracted to characterize the dry soybean seed kernel. The bag-of-feature model is used to generate a visual dictionary descriptor from the above two features, respectively. In order to exactly represent the image characteristics, we introduce the low-rank representation (LRR) method to eliminate the redundant information from the long joint two kinds of modal dictionary descriptors. The multiclass support vector machine algorithm is used to classify the encoding LRR of the jointly multi-modal bag of features. We validate our JMBoF classification algorithm on the soybean seed image dataset. The proposed method significantly outperforms the state-of-the-art single-modal bag of features methods in the literature, which could contribute in the future as a significant and valuable technology in postharvest dry soybean seed classification procedure.

6.
Nanoscale ; 11(46): 22343-22350, 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31728477

RESUMO

The design of pH-sensitive supramolecular drug delivery systems for efficient antineoplastic drug delivery remains a huge challenge. Herein, we describe the development of pH-responsive core-shell tecto dendrimers (CSTDs) formed using benzimidazole (BM)-modified generation 3 (G3) poly(amidoamine) (PAMAM) dendrimers (G3.NHAc-BM) as a shell and ß-cyclodextrin (CD)-modified G5 PAMAM dendrimers (G5.NHAc-CD) as a core. By virtue of the host-guest recognition and pH-responsiveness of BM/ß-CD assembly, the pH-sensitive supramolecular CSTDs of G5.NHAc-CD/BM-G3.NHAc were formed and adopted to encapsulate the anticancer drug doxorubicin (DOX) via hydrophobic interactions for pH-responsive drug delivery applications. The synthesis of dendrimer derivatives and the loading of the DOX were well characterized via different methods. We show that the encapsulated DOX can be released in a sustained manner with a rapid release speed under a slightly acidic pH condition (pH < 6), which is similar to acidic tumor microenvironment. The enhanced intracellular release of DOX and improved anticancer activity of the drug-loaded pH-responsive CSTDs were demonstrated and compared with the control CSTDs formed without pH-responsiveness through flow cytometry and viability assays of cancer cells. Furthermore, the pH-sensitive CSTDs also showed efficient drug penetration and growth inhibition of three-dimensional tumor spheroids owing to the faster DOX release in an acidic pH environment. The pH-sensitive G5.NHAc-CD/BM-G3.NHAc CSTDs may be employed as a valuable intelligent delivery system for various anticancer drugs.

7.
Chin J Nat Med ; 17(10): 792-800, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31703760

RESUMO

Polysaccharide from traditional Chinese herb, Saposhnikovia divaricata (Turcz.) Schischk. (SD) was extracted, fractionated and characterized in this work. Four fractions were prepared. Their molecular weight, monosaccharide compositions, linkage modes and structural properties were characterized with SEC-MALS-RI, HPAEC-PAD, GC-MS and NMR. SDP1 was assigned as a 1, 4-α-glucan with small amount of O-6 linked branches. SDP2 contained a big amount of the 1, 4-α-glucan and a small amount of arabinogalactan, while SDP3 possessed relatively lower amount of the 1, 4-α-glucan and a big amount of the arabinogalactan. SDP4 was defined as a pectic arabinogalactan. Four fractions showed antioxidant activities in both molecular and cellular levels and their activity was ranked as SDP4 ≈ SDP3>SDP2>SDP1. The 1, 4-α-glucan in SDP1 had the weakest, while SDP3 and SDP4 showed similar and the highest antioxidant activity. The arabinogalactan was the major component of both SDP3 and SDP4, which significantly contributed to the antioxidant activity of SDP.

8.
Biomolecules ; 9(10)2019 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-31623354

RESUMO

: The whitefly, Bemisia tabaci, is an important invasive economic pest of agricultural crops worldwide. ß-ionone has a significant oviposition repellent effect against B. tabaci, but the olfactory molecular mechanism of this insect for recognizing ß-ionone is unclear. To clarify the binding properties of odorant-binding proteins (OBPs) with ß-ionone, we performed gene cloning, evolution analysis, bacterial expression, fluorescence competitive binding assay, and molecular docking to study the binding function of OBP1 and OBP4 on ß-ionone. The results showed that after the OBP1 and OBP4 proteins were recombined, the compound ß-ionone exhibited a reduction in the fluorescence binding affinity to <50%, with a dissociation constant of 5.15 and 3.62 µM for OBP1 and OBP4, respectively. Our data indicate that ß-ionone has high affinity for OBP1 and OBP4, which play a crucial role in the identification of oviposition sites in B. tabaci. The findings of this study suggest that whiteflies employ ß-ionone compound in the selection of the suitable egg-laying sites on host plants during the oviposition behavior.

9.
Macromol Biosci ; 19(11): e1900272, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31531955

RESUMO

Nanogels (NGs) are 3-dimensional (3D) networks composed of hydrophilic or amphiphilic polymer chains, allowing for effective and homogeneous encapsulation of drugs, genes, or imaging agents for biomedical applications. Polyethylenimine (PEI), possessing abundant positively charged amine groups, is an ideal platform for the development of NGs. A variety of effective PEI-based NGs have been designed and much effort has been devoted to study the relationship between the structure and function of the NGs. In particular, PEI-based NGs can be prepared either using PEI as the major NG component or using PEI as a crosslinker. This review reports the recent progresses in the design of PEI-based NGs for gene and drug delivery and for bioimaging applications with a target focus to tackle the diagnosis and therapy of cancer.

10.
Int J Mol Sci ; 20(14)2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31311085

RESUMO

The sycamore lace bug, Corythucha ciliata (Say) is a highly invasive pest insect that feeds on sycamore trees (Platanus spp.) worldwide. The interaction between Platanus species and this insect pest has not yet been studied at the molecular level. Therefore, a recent study was conducted to compare the gene expression and metabolite profiles of Platanus acerifolia leaves in response to C. ciliata feeding damage after 24 and 48 h. We employed high throughput RNA sequencing (RNA- seq) to identify a total of 2,828 significantly differentially expressed genes (DEGs) after C. ciliata feeding. In addition, 303 unigenes were found to be up-regulated at both time points. Moreover, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that monoterpenoid biosynthesis, the linoleic acid metabolism pathway, and alpha- linolenic acid metabolism were the most prominent pathways among the DEGs. Further analysis of the metabolite profiles showed that nine metabolites were significantly different before and after C. ciliata damage. In addition, we analyzed DEGs detected in the P. acerifolia and C. ciliata interaction using Mapman. The terpene synthase gene family was also identified. We suggest that the results obtained from DEGs and metabolite analysis can provide important information for the identification of genes involved in the P. acerifolia-C. ciliata interaction, which might be necessary for controlling C. ciliata efficiently.


Assuntos
Hemípteros/patogenicidade , Magnoliopsida/genética , Metaboloma , Transcriptoma , Alquil e Aril Transferases/genética , Alquil e Aril Transferases/metabolismo , Animais , Regulação da Expressão Gênica de Plantas , Ácidos Linoleicos/metabolismo , Magnoliopsida/metabolismo , Magnoliopsida/parasitologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Estresse Fisiológico , Terpenos/metabolismo
11.
Plant Methods ; 14: 64, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30065777

RESUMO

Background: The images of different flower species had small inter-class variations across different classes as well as large intra-class variations within a class. Flower classification techniques are mainly based on the features of color, shape and texture, however, the procedure always involves too many heuristics as well as manual labor to tweak parameters, which often leads to datasets with poor qualitative and quantitative measures. The current study proposed a deep architecture of convolutional neural network (CNN) for the purposes of improving the accuracy of identifying the white flowers of Fragaria × ananassa from other three wild flower species of Androsace umbellata (Lour.) Merr., Bidens pilosa L. and Trifolium repens L. in fields. Results: The explored CNN architecture consisted of eightfolds of learnable weights including 5 convolutional layers and 3 fully connected layers, which received a true color 227 × 227 pixels flower image as its input. The developed CNN detector was able to classify the instances of flowers at overall average accuracies of 99.2 and 95.0% in the training and test procedure, respectively. The state-of-the-art CNN model was compared with the classical models of the scale-invariant feature transform (SIFT) features and the pyramid histogram of orientated gradient (PHOG) features combined with the multi-class support vector machine (SVM) algorithm. The proposed model turned out to be much more accurate than the traditional models of SIFT + SVM at overall average accuracies of 82.9 and 55.6% in the training and test procedure and PHOG + SVM at overall average accuracies of 78.3 and 63.1%, respectively. Conclusions: The proposed state-of-the-art CNN method demonstrates that artificial intelligence is capable of precise classification of the white flower images, whose accuracy is comparable to traditional algorithms. The presented algorithm can be further used for the discrimination of white wild flowers in fields.

12.
Nat Commun ; 9(1): 3290, 2018 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-30120242

RESUMO

Multiphoton fluorescence microscopy (MPM), using near infrared excitation light, provides increased penetration depth, decreased detection background, and reduced phototoxicity. Using stimulated emission depletion (STED) approach, MPM can bypass the diffraction limitation, but it requires both spatial alignment and temporal synchronization of high power (femtosecond) lasers, which is limited by the inefficiency of the probes. Here, we report that upconversion nanoparticles (UCNPs) can unlock a new mode of near-infrared emission saturation (NIRES) nanoscopy for deep tissue super-resolution imaging with excitation intensity several orders of magnitude lower than that required by conventional MPM dyes. Using a doughnut beam excitation from a 980 nm diode laser and detecting at 800 nm, we achieve a resolution of sub 50 nm, 1/20th of the excitation wavelength, in imaging of single UCNP through 93 µm thick liver tissue. This method offers a simple solution for deep tissue super resolution imaging and single molecule tracking.

13.
Front Physiol ; 9: 354, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29681864

RESUMO

The spread of the exotic insect pest sycamore lace bug Corythucha ciliata (Say) is increasing worldwide. The identification of behaviorally active compounds is crucial for reducing the current distribution of this pest. In this study, we identified and documented the expression profiles of genes encoding chemosensory proteins (CSPs) in the sycamore lace bug to identify CSPs that bind to the alarm pheromone geraniol. One CSP (CcilCSP2) that was highly expressed in nymph antennae was found to bind geraniol with high affinity. This finding was confirmed by fluorescence competitive binding assays. We further discovered one candidate chemical, phenyl benzoate, that bound to CcilCSP2 with even higher affinity than geraniol. Behavioral assays revealed that phenyl benzoate, similar to geraniol, significantly repelled sycamore lace bug nymphs but had no activity toward adults. This study has revealed a novel repellent compound involved in behavioral regulation. And, our findings will be beneficial for understanding the olfactory recognition mechanism of sycamore lace bug and developing a push-pull system to manage this pest in the future.

14.
Artif Cells Nanomed Biotechnol ; 46(sup1): 488-498, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29374979

RESUMO

In this study, we report the synthesis, characterization and utilization of 99mTc-labelled polyethylenimine-entrapped gold nanoparticles (99mTc-Au-PENPs) for dual mode single-photon emission computed tomography/computed tomography (SPECT/CT) imaging applications. Polyethylenimine (PEI) was selected as a platform to conjugate with diethylene triamine pentacetate acid (DTPA) and polyethylene glycol monomethyl ether to synthesize Au PENPs, followed by acetylation or hydroxylation modification of the remaining PEI surface amine groups and radiolabelling of 99mTc. The generated multifunctional 99mTc-Au-PENPs with different surface groups (acetyl or hydroxyl) were characterized via different methods. The Au PENPs before 99mTc labelling are colloidally stable, haemocompatibility and noncytotoxic at an Au concentration up to 100 µM. The 99mTc-labelled Au PENPs exhibit high radiochemical purity, good stability and SPECT/CT imaging performance of different organs and lymph node. The designed strategy to use the radionuclide labelling technique and PEI-facilitated versatile nanoplatform may be extended to develop various novel nanoprobes for precision imaging applications.


Assuntos
Ouro/química , Nanopartículas Metálicas/química , Polietilenoimina/química , Tomografia Computadorizada com Tomografia Computadorizada de Emissão de Fóton Único/métodos , Tecnécio/química , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Humanos , Marcação por Isótopo , Teste de Materiais , Camundongos , Polietilenoimina/farmacocinética , Polietilenoimina/toxicidade , Coelhos , Linfonodo Sentinela/diagnóstico por imagem , Distribuição Tecidual
15.
Pathol Res Pract ; 213(4): 394-399, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28283209

RESUMO

AIM: The use of saliva as a diagnostic fluid enables non-invasive sampling and thus is a prospective sample for disease tests. This study fully utilized the information from the salivary transcriptome to characterize pancreatic cancer related genes and predict novel salivary biomarkers. METHODS: We calculated the enrichment scores of gene ontology (GO) and pathways annotated in Kyoto Encyclopedia of Genes and Genomes database (KEGG) for pancreatic cancer-related genes. Annotation of GO and KEGG pathway characterize the molecular features of genes. We employed Random Forest classification and incremental feature selection to identify the optimal features among them and predicted novel pancreatic cancer-related genes. RESULTS: A total of 2175 gene ontology and 79 KEGG pathway terms were identified as the optimal features to identify pancreatic cancer-related genes. A total of 516 novel genes were predicted using these features. We discovered 29 novel biomarkers based on the expression of these 516 genes in saliva. Using our new biomarkers, we achieved a higher accuracy (92%) for the detection of pancreatic cancer. Another independent expression dataset confirmed that these novel biomarkers performed better than the previously described markers alone. CONCLUSION: By analyzing the information of the salivary transcriptome, we predict pancreatic cancer-related genes and novel salivary gene markers for detection.


Assuntos
Biomarcadores Tumorais/genética , Perfilação da Expressão Gênica/métodos , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/genética , Saliva/química , Ontologia Genética , Humanos , Reação em Cadeia da Polimerase
16.
Am J Transl Res ; 9(1): 103-114, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28123637

RESUMO

miR-34a is an important molecule that can inhibit the tumor growth. This study aimed to investigate the functional role of miR-34a in hepatocellular carcinoma (HCC) and explore the interaction between miR-34a and histone deacetylase 1 (HDAC1). RT-qPCR was employed to detect the mRNA expression of miR-34a and HDAC1 in 60 HCC tissues. Results showed miR-34a expression in HCC tissues was significantly lower than in normal tissues (P<0.05), but HDAC1 expression in HCC tissues was markedly higher than in normal tissues (P<0.05). In addition, miR-34a expression was negatively related to HDAC1 expression. miR-34a mimic was transfected into HCC cell lines (HepB3 and HepG2). CCK8 assay, colony formation assay and flow cytometry showed miR-34a over-expression could inhibit the proliferation of HCC cells and induce their apoptosis. Western blotting indicated miR-34a over-expression down-regulated the expression of Bcl-2, procaspase-3, procaspase-9 and c-Myc, but up-regulate p21 expression. Bioinformatics analysis indicated HDAC1 was a target gene of miR-34a. Dual Luciferase Reporter Gene Assay and retrieval assay showed miR-34a could act at the 3'UTR of HDAC1 gene to regulate its expression. Thus, miR-34a may inhibit the proliferation of HCC cells and induce their apoptosis via regulating HDAC1 expression. Our findings provide evidence for the diagnosis and therapeutic target of HCC.

17.
Zhonghua Nan Ke Xue ; 23(10): 908-911, 2017 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-29727541

RESUMO

Objective: To investigate the clinical effect of modified Snodgrass surgical technique in the treatment of hypospadias. METHODS: We retrospectively analyzed the clinical data about 212 cases of hypospadias treated by urethroplasty from January 2008 to October 2016, 94 with the modified Snodgrass technique, namely with a silk line in addition to the urethral suture to make easier postoperative removal of the suture (group A), and the other 118 with the conventional Snodgrass technique (group B). The urethral suture was removed at 10 days after surgery for the patients in group A. We compared the success rate of surgery and incidence of postoperative complications between the two groups. RESULTS: Compared with group B, group A showed a significantly higher success rate of surgery (81.36% vs 91.49%, P <0.05) but lower incidence rates of postoperative incisional infection (12.71% vs 4.26%, P <0.05) and urinary fistula (16.10% vs 6.38%, P <0.05). No statistically significant difference was found in the incidence of urethral stenosis between the two groups (2.54% vs 2.13%, P >0.05). CONCLUSIONS: The modified Snodgrass technique can improve the success rate of surgery and reduce the incidence rates of incisional infection and urinary fistula, which deserves wide clinical application.


Assuntos
Hipospadia/cirurgia , Uretra/cirurgia , Criança , Humanos , Incidência , Lactente , Masculino , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/prevenção & controle , Estudos Retrospectivos , Infecção da Ferida Cirúrgica/epidemiologia , Técnicas de Sutura , Estreitamento Uretral/epidemiologia , Fístula Urinária/prevenção & controle
18.
Biomed Opt Express ; 7(5): 1797-814, 2016 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-27231622

RESUMO

In near infrared fluorescence-guided surgical oncology, it is challenging to distinguish healthy from cancerous tissue. One promising research avenue consists in the analysis of the exogenous fluorophores' lifetime, which are however in the (sub-)nanosecond range. We have integrated a single-photon pixel array, based on standard CMOS SPADs (single-photon avalanche diodes), in a compact, time-gated measurement system, named FluoCam. In vivo measurements were carried out with indocyanine green (ICG)-modified derivatives targeting the αvß 3 integrin, initially on a genetically engineered mouse model of melanoma injected with ICG conjugated with tetrameric cyclic pentapeptide (ICG-E[c(RGD f K)4]), then on mice carrying tumour xenografts of U87-MG (a human primary glioblastoma cell line) injected with monomeric ICG-c(RGD f K). Measurements on tumor, muscle and tail locations allowed us to demonstrate the feasibility of in vivo lifetime measurements with the FluoCam, to determine the characteristic lifetimes (around 500 ps) and subtle lifetime differences between bound and unbound ICG-modified fluorophores (10% level), as well as to estimate the available photon fluxes under realistic conditions.

19.
Nanoscale ; 8(10): 5567-77, 2016 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-26890691

RESUMO

Development of new long-circulating contrast agents for computed tomography (CT) imaging of different biological systems still remains a great challenge. Here, we report the design and synthesis of branched polyethyleneimine (PEI)-stabilized gold nanoparticles (Au PSNPs) modified with polyethylene glycol (PEG) for blood pool, lymph node, and tumor CT imaging. In this study, thiolated PEI was first synthesized and used as a stabilizing agent to form AuNPs. The formed Au PSNPs were then grafted with PEG monomethyl ether via PEI amine-enabled conjugation chemistry, followed by acetylation of the remaining PEI surface amines. The formed PEGylated Au PSNPs were characterized via different methods. We show that the PEGylated Au PSNPs with an Au core size of 5.1 nm have a relatively long half-decay time (7.8 h), and display a better X-ray attenuation property than conventionally used iodine-based CT contrast agents (e.g., Omnipaque), and are hemocompatible and cytocompatible in a given concentration range. These properties of the Au PSNPs afford their uses as a contrast agent for effective CT imaging of the blood pool and major organs of rats, lymph node of rabbits, and the xenografted tumor model of mice. Importantly, the PEGylated Au PSNPs could be excreted out of the body with time and also showed excellent in vivo stability. These findings suggest that the formed PEGylated Au PSNPs may be used as a promising contrast agent for CT imaging of different biological systems.


Assuntos
Meios de Contraste/química , Linfonodos/diagnóstico por imagem , Nanopartículas Metálicas/química , Neoplasias/diagnóstico por imagem , Polietilenoglicóis/química , Polietilenoimina/química , Tomografia Computadorizada por Raios X , Animais , Materiais Biocompatíveis/química , Linhagem Celular , Sobrevivência Celular , Coloides/química , Ouro/química , Hemólise , Humanos , Iodo/química , Linfonodos/patologia , Espectroscopia de Ressonância Magnética , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Nanotecnologia , Transplante de Neoplasias , Coelhos , Ratos , Ratos Sprague-Dawley , Compostos de Sulfidrila/química , Raios X
20.
Anal Chim Acta ; 891: 43-61, 2015 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-26388363

RESUMO

Although the coupling of GC/MS with atmospheric pressure ionization (API) has been reported in 1970s, the interest in coupling GC with atmospheric pressure ion source was expanded in the last decade. The demand of a "soft" ion source for preserving highly diagnostic molecular ion is desirable, as compared to the "hard" ionization technique such as electron ionization (EI) in traditional GC/MS, which fragments the molecule in an extensive way. These API sources include atmospheric pressure chemical ionization (APCI), atmospheric pressure photoionization (APPI), atmospheric pressure laser ionization (APLI), electrospray ionization (ESI) and low temperature plasma (LTP). This review discusses the advantages and drawbacks of this analytical platform. After an introduction in atmospheric pressure ionization the review gives an overview about the history and explains the mechanisms of various atmospheric pressure ionization techniques used in combination with GC such as APCI, APPI, APLI, ESI and LTP. Also new developments made in ion source geometry, ion source miniaturization and multipurpose ion source constructions are discussed and a comparison between GC-FID, GC-EI-MS and GC-API-MS shows the advantages and drawbacks of these techniques. The review ends with an overview of applications realized with GC-API-MS.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Espectrometria de Massas por Ionização por Electrospray/métodos , Animais , Pressão Atmosférica , Desenho de Equipamento , Cromatografia Gasosa-Espectrometria de Massas/instrumentação , Humanos , Metabolômica/instrumentação , Metabolômica/métodos , Espectrometria de Massas por Ionização por Electrospray/instrumentação
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