Ding Longjiang's work has been accepted on JACS, Congratulations!
READ MOREIn this work, we have observed that OSPs-doped solid silica nanoparticles show good response to molecular oxygen. They not only show good sensitivity and fast response to oxygen but also exhibit excellent size and morphology control and good biocompatibility. Interestingly, oxygen-sensing performance can be tuned by changing the types of OSPs and silica morphologies. Because of their “clean” outer surface, these nanosensors can be further functionalized with arbitrary units for intracellular active-targeting and multiple purposes of applications. We have demonstrated the ease of functionalization by modifying the surface of nanosensors with organelle-targeting groups and used them for sensing oxygen concentration at subcellular level. Owing to the long luminescent lifetime of the nanosensors, we are able to image intracellular oxygen concentration using our custom-built microscopic rapid lifetime imaging system. The combination of rapid lifetime imaging technique with solid-silica based nanosensors shows superior accuracy and reproducibility, which provides important tools for intracellular oxygen studies, and allows us quantitatively imaging and tracing intracellular oxygen concentration over time and in situ with millisecond time resolution.
READ MOREIn this work, we report quadruple-fluorophore-labeled serum albumins as triple nanosensors for simultaneously imaging intracellular pH, oxygen and temperature. The nanosensors exhibit good biocompatibility and are biodegradable, which endows them suitable for intracellular studies without severely interrupting normal cellular activities. The triple nanosensors are constructed using serum albumins as building blocks. Native bovine serum albumins were modified with amino groups to increase the number of amino groups on protein surface. The reactive amino groups on protein surface were then covalently labeled with four fluorophores, which forms he triple nanosensors. Fluorophores were carefully selected to prevent self-quenching, and signal cross-talking. All three parameters were measured in referenced mode, which greatly enhances the precision and accuracy of intracellular measurements. The influences of cellular autofluorescence and system alignment have been greatly suppressed. Results show the nanosensors have good responses to dissolved oxygen, pH and temperature in the physiological range, which is beneficial for intracellular studies. These nanosensors have been proved to be biodegradable, and can be easily taken up by cells via endocytosis. The triple nanosensors can be directly used for sensing and imaging intracellular oxygen, pH and temperature values.
In this work, we have developed a highly-sensitive dissolved oxygen sensor with excellent mechanical stability and self-cleaning capability. The sensor composes of a micro/nano hierarchical structured superhydrophobic coating that is doped with oxygen-sensitive probe. The hierarchical structure was then solidified using silicone resin to endow the sensor film with good mechanical stability. After tape-peeling, intensive scratching and sandpaper abrasion, the sensor film still maintains good superhydrophobic nature with contact angle larger than 150 o. Owing to the porous structure and high gas permeability of silicone resin, the sensor showed excellent quenchability, toward oxygen quenching with I0/I100 over 77. Because of its superhydrophobic property, algae, biofilm and clams are difficult to adhere on the surface of the sensing film. This feature keeps the sensor surface clean over long-term usage, and there is no need to install cleaning brush, which will make sensor design much simple, more energy-saving and with largely-extended service life. Moreover, the fabrication of the sensor film is very simple, and there is no sophisticated synthesis and fabrication technique involved, which could be applied for massive production.
READ MOREIn this work, a lysosome-targeting nanosensor has been designed for simultaneous imaging of pH values and temperature in HeLa cells. The dual nanosensor responds to pH values in the range from 3.0 to 9.0, and to temperature in the range from 20 to 60 °C. Owing to its good biocompatibility and good sensitivity, the dual nanosensor was used to monitor changes in local pH values and temperature in the lysosome of HeLa cells. The nanosensors could be easily prepared and the surface functionalization technology is already well established. The remaining surface functional groups on nanosensors can be further explored for cellular active-targeting, carrying drugs, imaging, and tracking purposes.
In this work, we are introducing a new background-subtraction strategy, which has been proved to be a powerful tool to standardize the sensor response. By subtracting the scattered background light at a long wavelength, every oxygen sensor film exhibits an identical calibration curve and sensitivity, regardless of the physiochemical properties of the sensor film and instrumental setups. This strategy allows us to develop simple oxygen sensor devices with much lower cost, and the sensor can be calibrated after production. During their application, there is no need to recalibrate them, which is beneficial for their applications in industry, especially for long-term monitoring of oxygen concentration.
READ MOREIntracellular pH is a vital parameter that precisely controls cell functionalities, activities and cellular events. Abnormal intracellular pH is always closely related to the healthy status of cells, which is further translated into pathological changes in a macro perspective. In this chapter, we will start from illustrating the importance of measuring intracellular pH, and further discuss how to design optical nanosensors for sensing and imaging intracellular pH. The state of the art technology in intracellular pH sensing and imaging will be reviewed, nanomaterials that are used for constructing intracellular pH sensors will be summarized and the perspective of nanomaterials for intracellular pH sensing and imaging will be given at the end.
READ MOREIn this work, we have developed a highly sensitive, fully reversible, and reliable optical sensor for H2O2, with fast response and excellent stability. Highly sensitive oxygen sensor film was integrated with an ultrastable and highly efficient catalytical layer to form a sensor film, which can rapidly convert H2O2 into oxygen. The concentration of decomposed oxygen was sensitively measured by a luminescence-quenching-based oxygen sensor. Owing to our in situ growth strategy and the rational-designed nanostructure, the sensor exhibits extremely high stability over long time without observed loss of performance. The specially designed fibrous nanostructure also largely enriched catalyst concentration in the sensor film, which ensures the sensor having fast response (<1 min), good stability, and full reversibility. Because of the simplicity of the sensor design, the new H2O2 sensor is fully compatible with all commercial-available optical oxygen sensor devices, which makes the application of such sensors much easier and more economically friendly.
Lian Ying is a Ph.D student in her first year study, and has published one paper in just half of a year research. Congratulations!
In this work, we have described the synthesis of Cyanine dye doped silica nanoparticles. Cyanine dyes has been widely used in biological imaging since its attractive features of long emission wavelength. However, the dye is not very stable and tends to degrade in harsh conditions. We have supperisedly observed that most of cyanine dyes cannot be encapsulated via water-in-oil emulsion approach to form dye-doped silica nanoparticles, which is out of expectation. However, Cy-doped silica particle can be easily synthesized via Stober apporach which has good morphology, size distribution and Brightness.