Designed Synthesis of Dual Emitting Silicon Quantum Dot for Cell Imaging: Direct Labeling of Alpha 2-HS-Glycoprotein.

The innocent silicon quantum dots (SQDs) having dual emissive property (blue in VIS and red in NIR), high photostability, and freedom from auto fluorescence are designed and synthesized for the first time using ethylene glycol. A new attempt has been made for direct labeling of Alpha 2-HS-Glycoprotein (Fetuin A) through functionalization of the synthesized dots by EDC coupling. The SQDs were characterized by FTIR, TEM, AFM, XRD, EDX, DLS, and TGA. The chemistry involved in the synthesis and functionalization of dots is elucidated in detail. The synthesized SQDs are suitable for live cell imaging as well as direct labeling of the Fetuin A in the NIR region. The direct labeling technique developed for Fetuin A imaging is robust, more specific, and simple, and reduces the number of incubation and washing steps and produces better quality data compared to the conventional method using Rhodamine B.

Silicon Quantum Dot-Based Fluorescent Probe: Synthesis Characterization and Recognition of Thiocyanate in Human Blood.

Allylamine-functionalized silicon quantum dots (ASQDs) of high photostability are synthesized by a robust inverse micelle method to use the material as a fluorescent probe for selective recognition of thiocyanate (a biomarker of a smoker and a nonsmoker). The synthesized ASQDs were characterized by absorption, emission, and Fourier transform infrared spectroscopy. Surface morphology is studied by transmission electron microscopy and dynamic light scattering. The synthesized material exhibits desirable fluorescence behavior with a high quantum yield. A selective and accurate (up to 10-10 M) method of sensing of thiocyanate anion is developed based on fluorescence amplification and quenching of ASQDs. The sensing mechanism is investigated and interpreted with a crystal clear mechanistic approach through the modified Stern-Volmer plot. The developed material and the method is applied to recognize the anion in the human blood sample for identification of the degree of smoking. The material deserves high potentiality in the field of bio-medical science.

Design and synthesis of reduced graphene oxide based supramolecular scaffold: A benign microbial resistant network for enzyme immobilization and cell growth.

The present study describes the synthesis, characterization and biological application of reduced graphene oxide - chitosan (GC) based benign supramolecular scaffold (SMS). Various spectroscopic and microscopic analyses established the supramolecular interaction in between rGO and chitosan. The active performance of the developed material towards microbial resistivity, in vitro cell growth and as a scaffold for enzyme immobilizing matrix illustrates its unique implementation. Immobilization of polyphenol oxidase (PPO) onto GC lowers the Michaelis- Menten constant (Km) value and facilitates to achieve maximum velocity at low substrate concentration. Importantly GC shows no noteworthy cytotoxicity towards Wistar rat macrophage cells. Moreover, incorporation of gold nanoparticle further strengthens the microbial resistance properties of GC as well as improves its biocompatibility by reducing cytotoxicity. Therefore these unique features may inspire it to appear in large scale for industrial utilization.