Secondary Structure Analysis of Single Silk Nanofibril through Infrared Nanospectroscopy.

Infrared nanospectroscopy (NanoIR) is a new experimental technique to research the secondary structure of protein-based nanoarchitectures in recent years. Compared with the conventional IR, NanoIR reveals to be an exquisite, sensitive, and accurate tool to analyze and image the single molecule secondary structure, which can reach up to high spatial resolution (10 nm). Here we present a detailed protocol to introduce how to study single silk nanofibril (SNF) and process the results by this routine. This protocol provides a useful method to demonstrate the microstructure of nanomaterials by NanoIR, displaying the potential application in analytical chemistry, biomaterials, and nanotechnologies.

Method of Using Raman Spectroscopy to Understand the Conformation of Fibrous Proteins.

Raman spectroscopy has been widely used in the research of fibrous proteins because of the insensitivity to moisture, less amount of sample, and better signal-to-noise ratio. In recent years, Raman spectroscopy is adopted to investigate the secondary structures of solid or aqueous protein, the conformation transition under different conditions (concentration, temperature, pressure, pH, chemical modification, external force, etc.), the orientation of the molecular chains, and some important chemical bonds. Here, we will introduce the methods for using Raman spectroscopy to analyze the conformation and orientation of samples, which would be an efficient method to get the "structure-property" relationship.

Dendritic organosilica nanospheres with large mesopores as multi-guests vehicle for photoacoustic/ultrasound imaging-guided photodynamic therapy.

Photodynamic therapy (PDT) is a minimally invasive treatment strategy that uses photosensitizers and light in combination with oxygen to generate cytotoxic singlet oxygen (1O2) to kill cancer cells by necrosis or apoptosis. However, the treatment effects are still not satisfactory because of the tumor hypoxia and the PDT-induced oxygen consumption. Here, we have successfully synthesized dendritic mesoporous organosilica nanoparticles (MONs) with large center-radial pore structure that can be used to simultaneously encapsulate indocyanine green (ICG, <1 nm) and macromolecule catalase (CAT, 2.0 nm × 6.0 nm × 9.0 nm) to overcome the tumor hypoxia. Upon 808 nm laser irradiation, ICG as the organic NIR dye can generate highly cytotoxic singlet oxygen (1O2) and other reactive oxygen species (ROS) to kill cancer cells and realize photoacoustic (PA) imaging. The catalase can decompose the endogenous H2O2 in malignant cancerous cells into O2 bubble to simultaneously intensify the ultrasound (US) imaging signal and enhance PDT efficacy. These results indicate that the ICG-CAT@MONs holds great promise in multimodal photoacoustic / ultrasound image-guided tumor PDT therapy.

Full-color tunable photoluminescent carbon dots based on oil/water interfacial synthesis and their applications.

Herein, we developed a facile method to produce high yield, full-color tunable photoluminescent (PL) carbon dots (CDs) at the oil/water interface. This unique synthesis method for CDs involved the use of the oil-soluble small molecule styrene as both the reactant and oil phase medium at low temperature (60 °C) through a catalytic-oxidation reaction in an aqueous system, which resulted in a high product yield (about 50 wt%). Interestingly, the hydroxy-rich CDs at the oil/water interface self-assembled into nanospheres (N-CDs) spontaneously via hydrogen-bond interactions in the presence of styrene droplets. Without any surface passivation, the N-CDs exhibited self-quenching-resistant and full-color tunable PL properties, which are highly desirable in the optoelectronic field. The mechanism of the formation of N-CDs and their emission is proposed for the first time, which provides insight into the possible chemical processes occurring during the preparation. These distinctive CDs have potential novel applications in PL coatings, smart wearable optoelectronic devices, light emitting diodes, full-color displays, and solar cells.

Protein-Induced Synthesis of Chiral Conducting Polyaniline Nanospheres.

A green and novel method for the synthesis of chiral conducting polyaniline was developed. Chiral polyaniline induced by protein was obtained by using the template-assisted polymerization route. The experimental results demonstrated that proteins such as bovine hemoglobin and bovine serum albumin had the capacity to direct enantio specificity of PANI which may be ascribed to the α-helix structure within the proteins. The achieved chiral conducting polyaniline exhibited nanometered, spherical shape according to scanning electron microscopy and transmission electron microscopy images. Moreover, the high degree of crystallinity and conductivity of chiral polyaniline induced by protein was acquired.