Signal Intensity Enhancement Research Articles

Tunable upconversion emission in Er3+/Yb3+ co-doped oxyfluoride glass ceramics containing NaYF4 nanocrystals by the incorporation of Li+ ions

Rare earth doped glass materials with efficient tunable upconversion emission are a challenging field of research in the development of advanced optical devices. In this paper, tunable upconversion emission was realized by incorporating Li+ ions in Er3+/Yb3+ co-doped oxyfluoride glass ceramics containing NaYF4 nanocrystals. The prepared glass ceramics samples experience significant enhancement of luminescence intensity (up to 15 times) under 980 nm excitation. Meanwhile, a composite yellow emission with adjustable CIE chromaticity coordinates was achievable by altering the doping concentration of Li+ ions. The XRD analysis, absorption spectra and Judd-Ofelt theoretical calculations consistently revealed that these phenomena were associated with the Li+ caused shrinkage/expansion of NaYF4 crystal cells, which offers the possibility of emission tuning. The relevant luminescence mechanism was discussed in detail. Furthermore, it may pave new avenue for optimizing novel oxyfluoride glass ceramics applied in various optoelectronic fields.

A dual responsive colorimetric/fluorescent turn-on sensor for highly selective, sensitive and fast detection of Fe3+ ions and its applications

A new dual responsive colorimetric and fluorescent turn-on sensor DN for Fe3+ based on Schiff base derivative was designed and synthesized by one-step reaction. The sensor DN exhibited highly selective, sensitive and fast recognition toward Fe3+ with distinct color change by naked eyes in DMSO/H2O (1:1, v/v) solution over other competitive metal ions. The interaction of DN with Fe3+ caused a significant enhancement in emission intensity due to the restricted C = N isomerization and the suppression of highly efficient photoinduced electron transfer (PET) process. The sensing complex DN-Fe3+ was well-characterized to be 1:2 by the Job’s plot, 1H NMR titration, FTIR, HR ESI-MS analysis and DFT studies. The detection limit of DN for Fe3+ was as low as 0.178 μM, which displayed high sensitivity towards Fe3+. The sensor DN-based filter paper strips can be used to conveniently and effectively detect Fe3+ ions by the naked eyes. Importantly, the sensor DN was further used for detecting Fe3+ in real water and food samples with acceptable results and good recoveries.

Correlation of 3-T MRI and CT findings with patient symptoms and treatment outcome in radiofrequency ablation of osteoid osteoma

ObjectiveThe aim of this prospective study was to evaluate pre- and post-treatment MRI and CT findings of osteoid osteoma (OO) patients treated with radiofrequency thermo-ablation (RFTA) and to compare these findings with visual analog scale (VAS) scores. MethodsSixteen patients (4 females and 12 males; mean age of 18.87 ± 8.75 years (range: 8–37)) with OO were examined with CT and MRI, at baseline and at an average of 3 months following the procedure. On pre- and post-procedural CT and MRIs, OO-related findings were recorded. Treatment success was evaluated with VAS scores. ResultsBaseline VAS scores were 8 or 9 and follow-up scores were 0 or 1, indicating no early recurrences.Nidus diameters decreased significantly after the procedure (p = 0.027, p = 0.002, and p = 0.002; and p = 0.001, p = 0.001, p = 0.001 for AP, ML and CC nidus diameters for CT and MRI, respectively).The mean nidus volume were significantly decreased after the procedure (p = 0.001, for CT and MRI).On post-procedural images, cortical thickening, the signal intensity and contrast enhancement of the nidus and the extent of periostitis were significantly decreased (p = 0.019, p = 0.001, p = 0.001 and p = 0.034, respectively). There was no significant change in nidus calcification, perinidal cortical and intramedullary sclerosis, periosteal reaction, bone deformity, bone marrow and soft tissue edema, joint effusion and synovitis after the procedure (p = 0.253, p = 0.062, p = 0.245, p = 1, p = 1, p = 0.429, p = 0.371, p = 0.625, p = 1). ConclusionAlthough the changes in imaging findings may be helpful in early follow-up of OO patients treated with RFTA, these changes alone cannot be used with accuracy in predicting treatment response. Level of EvidenceLevel IV, Therapeutic Study.

Novel sample-substrates for the determination of new psychoactive substances in oral fluid by desorption electrospray ionization-high resolution mass spectrometry

A reliable screening and non invasive method based on the use of microextraction by packed sorbent coupled with desorption electrospray ionization-high resolution mass spectrometry was developed and validated for the detection of new psychoactive substances in oral fluid. The role of different sample substrates in enhancing signal intensity and stability was evaluated by testing the performances of two polylactide-based materials, i.e. non-functionalized and functionalized with carbon nanoparticles, and a silica-based material compared to commercially available polytetrafluorethylene supports. The best results were achieved by using the non-functionalized polylactide substrates to efficiently ionize compounds in positive ionization mode, whereas the silica coating proved to be the best choice for operating in negative ionization mode. LLOQs in the low μg/L, a good precision with CV% always lower than 16% and RR% in the 83(±4)-120(±2)% range, proved the suitability of the developed method for the determination of the analytes in oral fluid. Finally, the method was applied for screening oral fluid samples for the presence of psychoactive substances during private parties, revealing mephedrone in only one sample out of 40 submitted to analysis.

Electrochemical and chemiluminescence properties of polyaniline/pectin hybrid nanocomposites based on graphene and CdS nanoparticles

Incorporation of CdS nanoparticles is a suitable strategy to improve interfacial features, electrical and optical properties in polyaniline/graphene composites. In the other hand, use of biopolymers in addition to the improvement of processability of polyaniline composites leads to the creation of a developed functional surface owing to the affinity of biopolymers with the surfaces of inorganic nanomaterials. For this purpose in this work, we synthesized a hydrolyzed pectin-polyaniline copolymer (HP-PA) and its nanocomposites with graphene (GR) and CdS nanoparticles via a heterogeneous emulsion polymerization method. The samples were identified by FTIR, XRD, SEM, TEM, EDX, DSC and TGA analyses and investigated via electrical, electrochemical and chemiluminescence properties. Electrical conductivity showed a large increase about three orders of magnitude in conductivity of the nanocomposites compared to the copolymer sample. Electrochemical analyses (CV and EIS) demonstrated higher charge transfer ability for the nanocomposites than the HP-PA copolymer and a substantial improvement in electrochemical performance of GR/CdS@HP-PA due to the reinforcing effect of the CdS nanoparticles in electron transfer process. The optical properties of the samples exhibited a significant enhancement of chemiluminescence intensity for GR/CdS@HP-PA nanocomposite owing to the supporting effect of CdS nanoparticles in electron transfers and light emission.

Enhanced in vivo Optical Imaging of the Inflammatory Response to Acute Liver Injury in C57BL/6 Mice Using a Highly Bright Near-Infrared BODIPY Dye.

Delving deeper is possible in whole-body in vivo imaging using a super-bright membrane-targeting BODIPY dye (BD). The dye was used to monitor homing of ex vivo fluorescently labelled neutrophils to an injured liver of dark-pigmented C57BL/6 mice. In vivo imaging system (IVIS) data conclusively showed an enhanced signal intensity and a higher signal-to-noise ratio in mice receiving neutrophils labelled with the BD dye relative to those labelled with a gold standard dye at 2 h post in vivo administration of fluorescently labelled cells. Fluorescence-activated cell sorting (FACS) confirmed that BD is nontoxic, and an exceptional cell labelling dye that opens up precision deep-organ in vivo imaging of inflammation in mice routinely used for biomedical research. The origin of enhanced performance is identified with the molecular structure and the distinct localisation of the dye within cells that enable remarkable changes in its optical parameters.

Synthesis, characterization and properties of hierarchically assembled antimony oxyhalides nanonetworks

The novel synthesis route has been developed for hierarchically structured; nanorods and nanosheets of Sb4O5Cl2 from a single precursor, with dimension range between 57–90 nm. X-ray powder diffraction analysis confirmed the monoclinic crystal symmetry in P21/c (14) with structure type Sb4O5Cl2 for both forms; the nanorods and nanosheets. Rietveld refinements and crystallite size investigations of the powder patterns revealed significant enhancement in intensity with subtle variation in the lattice parameters and crystallite size decrease in case of nanosheets in comparison to the nanorods assembly. Through scanning electron microscopy, a composition commensurate to Sb4O5Cl2 at% with averaged dimensions; dia. ∼90 nm, l ∼ 2 μm for nanorods and dia. ∼50–150 nm for nanosheets got corroborated. Owing to the quantum confinement a band gap widening was observed while moving from bulk to nano regime, i.e. 3.25, 3.31 and 3.34 eV, for bulk, nanosheets, and nanorods, respectively. In the case of nanosheets, the highest value of dielectric constant was observed, i.e. 87, as compared to nanorods and the bulk, i.e. 40 and 35.5, respectively. The nanosheets also showed the highest value of dielectric and tangent loss with an increase in frequency due to the least crystallite size of these nanonetworks. Nanosheets depicted the higher AC conductivity at low frequency due to the alignment of the charges but its value decreases at the higher frequency due to lack of time for charge reorientation. The hopping phenomenon was observed in all three cases with the most prominent one in bulk case at higher frequencies.

Signal Intensity Enhancement by Cavity Confinement of Laser-Produced Plasma

The effect of hemispherical cavity confinement on the laser-generated plasma plume has been studied and revealing a fivefold signal intensity enhancement in the spectra of copper. The plasma temperature ( $T$ ) and electron density ( $N_{e}$ ) with and without cavity confinements have been determined. The plasma parameters ( $T$ and $N_{e}$ ) in the cavity confinement configuration remain the same for the first few microseconds and thereafter decay exponentially. The trend of constant plasma parameters for the first few microseconds is attributed to the competition of two processes; compression of the plasma plume by the reflected shock waves and cooling of the plasma plume by losing its kinetic energy due to the collision of the ambient gases. The signal intensity enhancement can be attributed to the reheating or compression of plasma plume by the reflected shock waves.

Synthesis and Rational design of Europium and Lithium Doped Sodium Zinc Molybdate with Red Emission for Optical Imaging

Highly efficient fluorescent and biocompatible europium doped sodium zinc molybdate (NZMOE) nanoprobes were successfully synthesized via Polyol method. Non-radiative defect centres get reduced with Li+ co-doping in NZMOE nanoprobes. XRD spectra and Rietveld refinement confirmed successful incorporation of lithium ion and crystallinity was also improved with Li+ co-doping. The shape of phosphor is rod shaped, as determined by TEM. Significant enhancement in photoluminescence intensity was observed with 266, 395 and 465 nm excitations. Profound red emission was recorded for 5 at% Li+ co-doped NZMOE nanoprobes with 266 nm excitation. It shows high asymmetry ratio (~15), color purity (94.90%) and good quantum efficiency (~70%). Judd Ofelt parameters have been calculated to measure intensity parameters and radiative transition rates. In order to measure biocompatibility of the nanoprobes, cytotoxicity assays were performed with HePG2 cells. The fluorescence emitted from phosphor material treated HePG2 cells was also measured by Laser Scanning Confocal Microscopy. The bright red fluorescence in HePG2 cells treated with very low concentration (20 μg/ml) of phosphor material indicates that it could be a promising phosphor for biological detection or bio-imaging.

Building blocks for thoracic MRI: Challenges, sequences, and protocol design.

Thoracic MRI presents important and unique challenges. Decreased proton density in the lung in combination with respiratory and cardiac motion can degrade image quality and render poorly executed sequences uninterpretable. Despite these challenges, thoracic MRI has an important clinical role, both as a problem-solving tool and in an increasing array of clinical indications. Advances in scanner and sequence design have also helped to drive this development, presenting the radiologist with improved techniques for thoracic MRI. Given this evolving landscape, radiologists must be familiar with what thoracic MR has to offer. The first step in developing an effective thoracic MRI practice requires the creation of efficient and malleable protocols that can answer clinical questions. To do this, radiologists must have a working knowledge of the MR sequences that are used in the thorax, many of which have been adapted from use elsewhere in the body. These sequences can be broadly divided into three categories: traditional/anatomic, functional, and cine based. Traditional/anatomic sequences allow for the depiction of anatomy and pathologic processes with the ability for characterization of signal intensity and contrast enhancement. Functional sequences, including diffusion-weighted imaging, and high temporal resolution dynamic contrast enhancement, allow for the noninvasive measurement of tissue-specific parameters. Cine-based sequences can depict the motion of structures in the thorax, either with retrospective ECG gating or in real time. The purpose of this article is to review these categories, the building block sequences that comprise them, and identify basic questions that should be considered in thoracic MRI protocol design. Level of Evidence: 5 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2019;50:682-701.

Peptide-based building blocks as structural elements for supramolecular Gd-containing MRI contrast agents.

Magnetic resonance imaging (MRI) is one of the most important clinic diagnostic tool used to obtain high-quality body images. The administration of low-molecular-weight Gd complex-based MRI contrast agents (CAs) permits to increase the 1 H relaxation rate of nearby water molecules, thus modulating signal intensity and contrast enhancement. Even if highly accurate, MRI modality suffers from its low sensitivity. Moreover, low-molecular-weight CAs rapidly equilibrate between the intravascular and extravascular spaces after their administration. In order to improve their sensitivity and limit the extravasation phenomenon, several macromolecular and supramolecular multimeric gadolinium complexes (dendrimers, polymers, carbon nanostructures, micelles, and liposomes) have been designed until now. Because of their biocompatibility, low immunogenicity, low cost, and easy synthetic modification, peptides are attractive building blocks for the fabbrication of novel materials for biomedical applications. We report on the state of the art of supramolecular CAs obtained by self-assembly of three different classes of building blocks containing a peptide sequence, a gadolinium complex, and, if necessary, a third functional portion achieving the organization process.

Magnetic resonance imaging spectrum of spinal meningioma

PurposeTo evaluate magnetic resonance (MR) imaging findings of spinal meningioma and to determine the radiological subtypes based on the MR imaging findings and their respective clinical features. Material and methodsData for 105 patients with surgically treated and histopathologically diagnosed spinal meningiomas at our hospital between May 1, 2003 and May 1, 2017 were evaluated in this study. Two radiologists reviewed the characteristics of spinal meningiomas on MR images and categorized the spinal meningiomas into subtypes based on MR imaging findings. ResultsMost spinal meningiomas showed higher signal intensity than that of the spinal cord but lower than that of the subcutaneous fat on T2-weighted images (WI). 56 cases (54%) showed adjacent spinal cord signal changes. Meningiomas could be categorized according to MR imaging findings into type A: dural-based tumors with a homogeneous signal intensity and intense contrast enhancement (81 cases, 77%); type B: round or oval-shaped tumors with an internal hypointense portion on T2-weighted images (18 cases, 17%); type C: en plaque tumors (three cases, 3%); and type D: tumors with unusual findings and a heterogeneous appearance (three cases, 3%). All type C patients showed spinal cord signal changes. ConclusionsSpinal meningioma showed slightly high signal intensity rather than high signal intensity on T2-weighted images. Spinal cord signal changes were present in more than half of the cases. Clinical differences were observed among the different MR imaging types.

Thermal annealing induced strong photoluminescence enhancement in Ag-TiO2 plasmonic nanocomposite thin films

Thin films of Ag-TiO2 plasmonic nanocomposites were fabricated on silica glass substrates by a combined approach using thermal evaporation and RF magnetron sputtering. The optical and plasmonic response of Ag-TiO2 nanocomposites were tuned with the help of thermal annealing by varying the annealing temperature from 400 °C to 600 °C. The optical absorption spectra revealed the transformation of Ag nanolayer into Ag nanoparticles upon annealing. The band gap of Ag-TiO2 nanocomposite thin films varied from 3.09 eV to 2.53 eV due to annealing. AFM studies revealed growth of nanostructures in the Ag-TiO2 nanocomposites with increase in annealing temperature. The average nanoparticle size varied from 27 nm to 230 nm upon annealing. XRD results confirmed the appearance of Ag nanoparticles along with nanostructured anatase TiO2. The photoluminescence spectra of Ag-TiO2 nanocomposites revealed significant enhancement in intensity of UV and defect emissions upon annealing at 600 °C. The observed enhancement originated from the changes in the plasmonic properties of Ag nanostructures in the nanocomposite upon annealing. The observed significant enhancement in the UV emission arises due to the resonant coupling of surface plasmons of Ag nanoparticles with the band edge emission from TiO2 which significantly improved the number of electrons in the conduction band of TiO2. The PL enhancement in the visible region is ascribed to increased creation of shallow traps in TiO2 due to the presence of Ag nanoparticles. This work provides a simple route to strong enhancement in PL intensity of nanostructured TiO2 thin film which is very promising for applications in nanophotonics.

Colorimetric method for glucose detection with enhanced signal intensity using ZnFe2O4-carbon nanotube-glucose oxidase composite material.

In this paper, a composite material comprised of ZnFe2O4 nanomaterial, carbon nanotubes (CNT) and glucose oxidase (GOD) was synthesized and used for glucose detection. ZnFe2O4-CNT was formed by a one-step solvothermal approach using acid-treated CNT as precursor, then GOD was linked to it by coupling reaction between -NH2 and -COOH. After addition of glucose, which is oxidized by GOD, the intermediate product (H2O2) further oxidizes the 3,3',5,5'-tetramethylbenzidine (TMB) substrate and forms a blue product. This process was accelerated in the presence of peroxidase-mimic ZnFe2O4 nanomaterial and the detected signal intensity was correspondingly enhanced. The linear detection range of glucose was 0.8 to 250 μM, with a limit of detection of 0.58 μM. This may originate from (1) the limited diffusion of intermediate species, which resulted in enhanced local concentrations of reaction compounds; (2) enhanced electron transmission among CNT, GOD and ZnFe2O4; (3) the synergistic enhancement of catalytic activity of ZnFe2O4 compared with other metal oxides; (4) the high loading capacity of ZnFe2O4-CNT for GOD molecules, because of its high surface-to-volume ratio. Meanwhile, this method has reasonable selectivity, stability and reusability and can be used for real serum detection, which may be useful for the development of sensitive biosensors.

Dramatic enhancement in pH sensitivity and signal intensity through ligand modification of a dicobalt PARACEST probe.

The employment of an ancillary amine-substituted bisphosphonate ligand affords a dicobalt complex able to quantitate pH with a remarkably high sensitivity of 8.8(5) pH unit-1 at 37 °C through a ratiometric paramagnetic chemical exchange saturation transfer (PARACEST) approach, where the different pH dependences of amine and amide CEST peak intensities are utilized.

Heterodimeric Plasmonic Nanogaps for Biosensing.

We report the study of heterodimeric plasmonic nanogaps created between gold nanostar (AuNS) tips and gold nanospheres. The selective binding is realized by properly functionalizing the two nanostructures; in particular, the hot electrons injected at the nanostar tips trigger a regio-specific chemical link with the functionalized nanospheres. AuNSs were synthesized in a simple, one-step, surfactant-free, high-yield wet-chemistry method. The high aspect ratio of the sharp nanostar tip collects and concentrates intense electromagnetic fields in ultrasmall surfaces with small curvature radius. The extremities of these surface tips become plasmonic hot spots, allowing significant intensity enhancement of local fields and hot-electron injection. Electron energy-loss spectroscopy (EELS) was performed to spatially map local plasmonic modes of the nanostar. The presence of different kinds of modes at different position of these nanostars makes them one of the most efficient, unique, and smart plasmonic antennas. These modes are harnessed to mediate the formation of heterodimers (nanostar-nanosphere) through hot-electron-induced chemical modification of the tip. For an AuNS-nanosphere heterodimeric gap, the intensity enhancement factor in the hot-spot region was determined to be 106, which is an order of magnitude greater than the single nanostar tip. The intense local electric field within the nanogap results in ultra-high sensitivity for the presence of bioanalytes captured in that region. In case of a single BSA molecule (66.5 KDa), the sensitivity was evaluated to be about 1940 nm/RIU for a single AuNS, but was 5800 nm/RIU for the AuNS-nanosphere heterodimer. This indicates that this heterodimeric nanostructure can be used as an ultrasensitive plasmonic biosensor to detect single protein molecules or nucleic acid fragments of lower molecular weight with high specificity.

Photoluminescence Flickering and Blinking of Single CsPbBr3 Perovskite Nanocrystals: Revealing Explicit Carrier Recombination Dynamics.

To obtain an in-depth understanding of the dynamics and mechanism of carrier recombination in CsPbBr3 nanocrystals (NCs), we have investigated the photoluminescence (PL) of this material at the single-particle level using the time-tagged-time-resolved method. The study reveals two distinct types of PL fluctuations of the NCs, which are assigned to flickering and blinking. The flickering is found to be due to excess surface trap on the NCs, and the flickering single particles are transformed into blinking ones with significant enhancement of PL intensity and stability on postsynthetic surface treatment. Intensity-correlated lifetime analysis of the PL time trace reveals both trap-mediated nonradiative band-edge carrier recombination and positive trion recombination in single NCs. Dynamical and statistical analysis suggests a diffusive nature of the trap states to be responsible for the PL intermittency of the system. These findings throw light on the nature of the trap states, reveal the manifestation of these trap states in PL fluctuation, and provide an effective way to control the dynamics of CsPbBr3 NCs.

Neural Plastic Changes in the Subcortical Auditory Neural Pathway after Single-Sided Deafness in Adult Mice: A MEMRI Study.

Single-sided deafness (SSD) induces cortical neural plastic changes according to duration of deafness. However, it is still unclear how the auditory cortical changes accompany the subcortical neural changes. The present study aimed to find the neural plastic changes in the cortical and subcortical auditory system following adult-onset single-sided deafness (SSD) using Mn-enhanced magnetic resonance imaging (MEMRI). B57BL/6 mice (postnatal 8-week-old) were divided into three groups: the SSD-4-week group (postnatal 12-week-old, n = 11), the SSD-8-week group (postnatal 16-week-old, n = 11), and a normal-hearing control group (postnatal 8-week-old, n = 9). The left cochlea was ablated in the SSD groups. White Gaussian noise was delivered for 24 h before MEMRI acquisition. T1-weighted MRI data were analyzed from the cochlear nucleus (CN), superior olivary complex (SOC), lateral lemniscus (LL), inferior colliculus (IC), medial geniculate body (MG), and auditory cortex (AC). The differences in relative Mn2+-enhanced signal intensities (Mn2+SI) and laterality were analyzed between the groups. Four weeks after the SSD procedure, the ipsilateral side of the SSD showed significantly lower Mn2+SI in the CN than the control group. On the other hand, the contralateral side of the SSD demonstrated significantly lower Mn2+SI in the SOC, LL, and IC. These decreased Mn2+SI values were partially recovered at 8 weeks after the SSD procedure. The interaural Mn2+SI differences representing the interaural dominance were highest in CN and then became less prominently higher in the auditory neural system. The SSD-8-week group still showed interaural differences in the CN, LL, and IC. In contrast, the MG and AC did not show any significant intergroup or interaural differences in Mn2+SI. In conclusion, subcortical auditory neural activities were decreased after SSD, and the interaural differences were diluted in the higher auditory nervous system. These findings were attenuated with time. Subcortical auditory neural changes after SSD may contribute to the change in tinnitus severity and the outcomes of cochlear implantation in SSD patients.

A new “turn-on” fluorescent chemosensor for Zn2+ based on a diarylethene derivative and its practical applications

A new photochromic fluorescent chemosensor 1o based on a diarylethene derivative was designed and successfully synthesized. In this work, 1o acted as a “turn-on” fluorescence sensor for detecting Zn2+ in methanol solution with the characteristics of fast response, good sensitivity and high selectivity over other metal ions. Compared with the initial fluorescence emission peak of 1o, upon the addition of Zn2+, a new strong fluorescence emission peak centered at 582 nm appeared with a significant intensity enhancement (105-fold), and the fluorescent color of the 1o solution changed from darkness to bright yellow. The results of Job’s plot and HRMS determined the binding stoichiometry of 1:1 between 1o and Zn2+. Besides, the limit of detection (LOD) of 1o towards Zn2+ was calculated at very low concentration up to 13.4 nM. Moreover, the fluorescence signals of 1o were used to design a logic gate. Furthermore, 1o could also detect trace amounts of Zn2+ in real water samples, suggesting the practical application in environmental systems.

Stearic Acid-Grafted Chitooligosaccharide Nanomicelle System with Biocleavable Gadolinium Chelates as a Multifunctional Agent for Tumor Imaging and Drug Delivery.

Theranostic nanoplatforms are promising approaches for diagnosis and treatment. Here, we report a drug-loaded nanomicelle system with biocleavable gadolinium (Gd) chelates as a multifunctional biodegradable agent for simultaneous magnetic resonance imaging (MRI) and drug delivery. Self-assembled nanomicelles based on stearic acid-grafted chitooligosaccharide were utilized as vehicles. Gd chelates, DTPA-Gds, were linked to the nanomicelles via redox-responsive disulfide bonds, and hydrophobic drugs were encapsulated in the micelle cores. MRI and cargo delivery were investigated in orthotopic pancreatic tumor-bearing mice. In vivo MRI demonstrated that the biodegradable agent was cleaved by endogenous thiols after intravenous injection, and the released DTPA-Gds were eliminated rapidly. At the same time, the agent resulted in a greater contrast enhancement of T1-weighted MR signal intensity at the tumor region than Magnevist®, and the tumor boundaries were clearly defined for at least 2h. In addition, the agent possessed high drug-loading and tumor-targeting capacities. Loading content and encapsulation efficiency of docetaxel were 3.2% and 99.4%, respectively. Compared with Taxotere®, the commercially available docetaxel injection, the docetaxel-loaded agent significantly increased the drug concentration in tumor tissue in vivo. The fabricated multifunctional agent may serve as a biodegradable nanoscale MRI contrast agent and as a drug delivery system for tumor diagnosis and treatment.