Ingestible sensors are potentially a powerful tool for monitoring human health. Sensors have been developed that can, for example, provide pH and pressure readings or monitor medication, but capsules that can provide key information about the chemical composition of the gut are still not available. Here we report a human pilot trial of an ingestible electronic capsule that can sense oxygen, hydrogen, and carbon dioxide. The capsule uses a combination of thermal conductivity and semiconducting sensors, and their selectivity and sensitivity to different gases is controlled by adjusting the heating elements of the sensors. Gas profiles of the subjects were obtained while modulating gut microbial fermentative activities by altering their intake of dietary fibre. Ultrasound imaging confirmed that the oxygen-equivalent concentration profile could be used as an accurate marker for the location of the capsule. In a crossover study, variations of fibre intake were found to be associated with differing small intestinal and colonic transit times, and gut fermentation. Regional fermentation patterns could be defined via hydrogen gas profiles. Our gas capsule offers an accurate and safe tool for monitoring the effects of diet of individuals, and has the potential to be used as a diagnostic tool for the gut. NATuRE ELECTRONiCS

It is known that the unique layered structure of orthorhombic MoO3 (α-MoO3) facilitates the interaction with H2 gas molecules and that the surface-to-volume ratios of the crystallites play an important role in the process. MoO3 was deposited on a wide variety of transparent substrates using thermal evaporation in order to alter the surface-to-volume ratios of the crystallites. In situ Raman spectroscopy was employed to investigate the interaction between MoO3 and 1% H2 in both N2 and synthetic air environments, while incorporating Pd as a catalyst at room temperature. This study confirmed that the layered MoO3 with a high surface-to-volume ratio facilitated the H2 gas interaction. The Raman spectroscopy studies revealed that the H+ ions mainly interacted with the doubly coordinated oxygen atoms and caused the crystal transformation from the original α-MoO3 into the mixed structure of hydrogen molybdenum bronze and substoichiometric MoO3, eventually forming oxygen vacancies and water. It was also found that the presence of O2 during the H2 gas exposure caused the recombination of a number of oxygen vacancies and reduced the available surface catalytic sites for H2.

Increasing cell survival in stem cell therapy is an important challenge for the field of regenerative medicine. Here, we report theranostic mesoporous silica nanoparticles that can increase cell survival through both diagnostic and therapeutic approaches. First, the nanoparticle offers ultrasound and MRI signal to guide implantation into the peri-infarct zone and away from the most necrotic tissue. Second, the nanoparticle serves as a slow release reservoir of insulin-like growth factor (IGF)—a protein shown to increase cell survival. Mesenchymal stem cells labeled with these nanoparticles had detection limits near 9000 cells with no cytotoxicity at the 250 µg/mL concentration required for labeling. We also studied the degradation of the nanoparticles and showed that they clear from cells in approximately 3 weeks. The presence of IGF increased cell survival up to 40% (p<0.05) versus unlabeled cells under in vitro serum-free culture conditions.

Nanoparticles are a new class of imaging agent used for both anatomic and molecular imaging. Nanoparticle-based imaging exploits the signal intensity, stability, and biodistribution behavior of submicron-diameter molecular imaging agents. This review focuses on nanoparticles used in human medical imaging, with an emphasis on radionuclide imaging and MRI. Newer nanoparticle platforms are also discussed in relation to theranostic and multimodal uses.Key Words: nanoparticles; medical imaging; molecular imaging; nanoparticle; imaging and diagnostics Nucl Med 2016; 57:1833 57: -1837 57: DOI: 10.2967 Medical imaging offers rapid, longitudinal, and noninvasive visualization of the interior of living subjects. There are two main approaches to medical imaging, the first being anatomic imaging, which provides information on gross structure, and the second being molecular or functional imaging, which provides information on physiology and cellular processes such as metabolism, protein expression, and DNA synthesis (1). Although exogenous imaging agents are optional for anatomic imaging (e.g., MRI or CT contrast medium agents, which help improve tissue contrast), they are virtually a requirement for molecular imaging, especially within the realm of nuclear medicine, for which radioisotopes are required for single-photon emission CT (SPECT) or PET. JThe 3 main classes of imaging agents include small molecules, proteins, and nanoparticles. Most scans use small molecules, which are agents below 2,000 kDa and measure approximately 1 nm (e.g., 18 F-FDG for PET, iodinated small molecules for CT, and chelated gadolinium for MRI). Protein imaging agents, such as radiolabeled monoclonal antibodies, are less common but offer precise molecular information and are a growing area of research. Nanoparticles are a new and exciting class of imaging agent that can be used for both anatomic and molecular imaging.Their small size and unique properties (high ratio of surface area to volume) offer, first, intense and longitudinally stable imaging signals (quantum and C dots); second, different targeting strategies (passive targeting via the mononuclear phagocyte system or active targeting to specific molecular targets as a result of functionalization with ligands); third, high avidity (a large association constant brought about by the presence of multiple ligands per particle); fourth, theranostic capabilities (use for both diagnostic purposes, by generating an imaging signal, and therapeutic purposes, by delivering a drug payload); fifth, multimodal signal capabilities (detection of one nanoparticle by more than one imaging modality, making it suitable for deep tissue imaging, screening with MRI, and intraoperative guidance using superficial imaging with optical imaging); and sixth, multiplexing (detection of multiple different molecular targets simultaneously).Although many of these features have been demonstrated only in animal models, there are several nanoparticle formulations that have been transitioned into clinical practice. This revi...

This paper reports the electrowetting properties of ZnO nanorods. These nanorods were grown on indium tin oxide (ITO) substrates using different liquid-phase deposition techniques and hydrophobized with sputtered Teflon. The surfaces display superhydrophobic properties. When the applied voltages are less than 35 V, the contact angle change is small and exhibits instant reversibility. For higher voltages, larger contact angle changes were observed. However, the surface was not reversible after removing the applied voltage and required mechanical agitation to return to its initial superhydrophobic state.

It is well known that WO(3) interacts efficiently with H(2) gas in the presence of noble metals (such as Pd, Pt and Au) at elevated temperatures, changing its optical behaviors; and that its crystallinity plays an important role in these interactions. For the first time, we investigated the in situ Raman spectra changes of WO(3) films of different crystal phases, while incorporating Pd catalysts, at elevated temperatures in the presence of H(2). The Pd/WO(3) films were prepared using RF sputtering and subsequently annealed at 300, 400 and 500 °C in air in order to alter the dominant crystal phase. The films were then characterized using SEM, XRD, XPS, and both UV-VIS and Raman spectroscopy. In order to fundamentally study the process, the measurements were conducted when films were interacting with 1% H(2) in synthetic air at elevated sample temperatures (20, 60, 100 and 140 °C). We suggest that the changes of Raman spectra under such conditions to be mainly a function of the crystal phase, transforming from monoclinic to a mix phase of monoclinic and orthorhombic achieved via increasing the annealing temperature. The as-deposited sample consistently shows similar Raman spectra responses at different operating conditions upon H(2) exposure. However, increasing the annealing temperature to 500 °C tunes the optimum H(2) response operating temperature to 60 °C.

Raman spectroscopic imaging has shown great promise for improved cancer detection and localization with the use of tumor targeting surface enhanced Raman scattering (SERS) nanoparticles. With the ultrasensitive detection and multiplexing capabilities that SERS imaging has to offer, scientists have been investigating several clinical applications that could benefit from this unique imaging strategy. Recently, there has been a push to develop new image-guidance tools for surgical resection to help surgeons sensitively and specifically identify tumor margins in real time. We hypothesized that SERS nanoparticles (NPs) topically applied to breast cancer resection margins have the potential to provide real-time feedback on the presence of residual cancer in the resection margins during lumpectomy. Here, we explore the ability of SERS nanoparticles conjugated with a cluster of differentiation-47 (CD47) antibody to target breast cancer. CD47 is a cell surface receptor that has recently been shown to be overexpressed on several solid tumor types. The binding potential of our CD47-labeled SERS nanoparticles was assessed using fluorescence assisted cell sorting (FACS) on seven different human breast cancer cell lines, some of which were triple negative (negative expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2)). Xenograft mouse models were also used to assess the ability of our Raman imaging system to identify tumor from normal tissue. A ratiometric imaging strategy was used to quantify specific vs. nonspecific probe binding, resulting in improved tumor-to-background ratios. FACS analysis showed that CD47-labeled SERS nanoparticles bound to seven different breast cancer cell lines at levels 12-fold to 70-fold higher than isotype control-labeled nanoparticles (p < 0.01), suggesting that our CD47-targeted nanoparticles actively bind to CD47 on breast cancer cells. In a mouse xenograft model of human breast cancer, topical application of CD47-targeted nanoparticles to excised normal and cancer tissue revealed increased binding of CD47-targeted nanoparticles on tumor relative to normal adjacent tissue. The findings of this study support further investigation and suggest that SERS nanoparticles topically applied to breast cancer could guide more complete surgical resection during lumpectomy.

The intricate, hierarchical, highly reproducible, and exquisite biosilica structures formed by diatoms have generated great interest to understand biosilicification processes in nature. This curiosity is driven by the quest of researchers to understand nature's complexity, which might enable reproducing these elegant natural diatomaceous structures in our laboratories via biomimetics, which is currently beyond the capabilities of material scientists. To this end, significant understanding of the biomolecules involved in biosilicification has been gained, wherein cationic peptides and proteins are found to play a key role in the formation of these exquisite structures. Although biochemical factors responsible for silica formation in diatoms have been studied for decades, the challenge to mimic biosilica structures similar to those synthesized by diatoms in their natural habitats has not hitherto been successful. This has led to an increasingly interesting debate that physico-chemical environment surrounding diatoms might play an additional critical role towards the control of diatom morphologies. The current study demonstrates this proof of concept by using cationic amino acids as catalyst/template/scaffold towards attaining diatom-like silica morphologies under biomimetic conditions in ionic liquids.