Zhongde Mu

Hybrid mesoporous colloid photonic crystal array for high performance vapor sensing

A hybrid mesoporous photonic crystal vapor sensing chip was developed by introducing fluorescent dyes into mesoporous colloidal crystals. The sensing chip was capable of discriminating various kinds of vapors, as well as their concentrations, according to their fluorescence and reflective responses to vapor analytes.

Gold nanoparticle incorporated inverse opal photonic crystal capillaries for optofluidic surface enhanced Raman spectroscopy

Novel transducers are needed for point of care testing (POCT) devices which aim at facile, sensitive and quick acquisition of health related information. Recent advances in optofluidics offer tremendous opportunities for biological/chemical analysis using extremely small sample volumes. This paper demonstrates nanostructured capillary tubes for surface enhanced Raman spectroscopy (SERS) analysis in a flow-through fashion. The capillary tube integrates the SERS sensor and the nanofluidic structure to synergistically offer sample delivery and analysis functions. Inside the capillary tube, inverse opal photonic crystal (IO PhC) was fabricated using the co-assembly approach to form nanoscale liquid pathways. In the nano-voids of the IO PhC, gold nanoparticles were in situ synthesized and functioned as the SERS hotspots. The advantages of the flow-through SERS sensor are multifold. The capillary effect facilities the sample delivery process, the nanofluidic channels boosts the interaction of analyte and gold nanoparticles, and the PhC structure strengthens the optical field near the SERS hotspots and results in enhanced SERS signals from analytes. As an exemplary demonstration, the sensor was used to measure creatinein spiked in artificial urine samples with detection limit of 0.9 mg/dL.

Rapid identification of electricigens via silver-plated photonic crystal filters

Short acquisition time and small volumes of incubated bacterial cultures are ideal for the routine and rapid identification or screening of electricigens in research and applications of microbial fuel cells. In this study, a functional substrate based on colloidal photonic crystals (PCs) was developed both for the filtration and identification of electricigens by surface-enhanced Raman scattering (SERS). The fabrication of the substrate was simplified by electroless plating of silver on filtration-based self-assembled PCs on a filter membrane. The silver-plated ordered PC structure provided a 107-fold enhancement of Raman intensity compared to that obtained with a bare PC substrate. The substrate allowed for a “drop and measure” method of bacterial identification within 5 min with a 5 μL sample volume only. The results showed that not only the electricigens Geobacter sp. and Shewanella sp. could be discriminated with species and strain specificity, but also Geobacter sp. and pilus-mutated Geobacter sp. strains. The developed silver-plated PC filter offers tremendous opportunities in energetic, environmental, and clinical applications.

Chitin-Based Anisotropic Nanostructures of Butterfly Wings for Regulating Cells Orientation

In recent years, multiple types of substrates have been applied for regulating cell orientation. Among them, surface topography patterns with grooves or ridges have been widely utilizing for cell culturing. However, this construction is still complicated, low cost-effective and exhibits some technological limitations with either “top-down” or “bottom-up” approaches. Here, a simple and green method was developed by utilizing butterfly wings (Morpho menelaus, Papilio ulysses telegonus and Ornithoptera croesus lydius) with natural anisotropic nanostructures to generate cell alignment. A two-step chemical treatment was proposed to achieve more hydrophilic butterfly wings preceding cell culturing. Furthermore, calcein acetoxymethyl ester (Calcein-AM) staining and Methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay results demonstrated the appropriate viability of NIH-3T3 fibroblast cells on those butterfly wings. Moreover, the cells displayed a high degree of alignment in each specimen of these wings. We anticipate that those originating from natural butterfly wings will pose important applications for tissue engineering.

Multiplex and Label-free SERS Protein Assay Based on Colloidal Photonic Crystal Beads

AgNPs coupled photonic crystal beads for protein detection were demonstrated. Three proteins were successfully identified. This approach shows great potential applications for SERS-based protein identification and multiplex biomolecule diagnostics.