Cost Effective Silver Nanowire-Decorated Graphene Paper for Drop-on SERS Biodetection

The use of SERS for real-world bioanalytical applications represents a concrete opportunity, which, however, is being largely delayed by the inadequacy of existing substrates used to collect SERS spectra. In particular, the main bottleneck is their poor usability, as in the case of unsupported noble metal colloidal nanoparticles or because of the need for complex or highly specialized fabrication procedures, especially in view of a large-scale commercial diffusion. In this work, we introduce a graphene paper-supported plasmonic substrate for biodetection as obtained by a simple and rapid aerosol deposition patterning of silver nanowires. This substrate is compatible with the analysis of small (2 μL) analyte drops, providing stable SERS signals at sub-millimolar concentration and a detection limit down to the nanogram level in the case of hemoglobin. The presence of a graphene underlayer assures an even surface distribution of SERS hotspots with improved stability of the SERS signal, the collection of well-resolved and intense SERS spectra, and an ultra-flat and photostable SERS background in comparison with other popular disposable supports.

Development of High Performance Thin Layer Chromatography Method for Quantitation of Gallic Acid in Normacid Syrup: A Poly Herbal Formulation

Normacid syrup consisiting of 17 ingredients, used in the treatment of hyperacidity and gastritis. Gallic acid is one of the phytoconstituent present in Normacid syrup- a poly herbal formulation. In the present study an attempt has been made to develop a HPTLC method for quantitative estimation of gallic acid in dried fruits used in formulations. This HPTLC method was found to be reproducible, accurate, precise and detect gallic acid at nanogram level. The developed HPTLC method would be an important tool in the quality control method of poly herbal formulation. Keywords: HPTLC, Polyherbal, Gallic acid, Gastritis

DEVELOPMENT OF HIGH PERFORMANCE THIN LAYER CHROMATOGRAPHY METHOD FOR QUANTITATION OF ?-SITOSTEROL IN NORMACID SYRUP: A POLY HERBAL FORMULATION

Normacid syrup consisiting of 17 ingredients, used in the treatment of hyperacidity and gastritis. ?- Sitosterol is one of the phytoconstituent present in Normacid syrup- a poly herbal formulation. In the present study an attempt has been made to develop a HPTLC method for quantitative estimation of ?- Sitosterol in dried plant parts used in formulations. This HPTLC method was found to be reproducible, accurate, precise and detect ?- Sitosterol at nanogram level. The developed HPTLC method would be an important tool in the quality control method of poly herbal formulation. Keywords: HPTLC, Polyherbal, ?- Sitosterol, Gastritis

Quartz Enhanced Conductance Spectroscopy for Polymer Nano-Mechanical Thermal Analysis

A fast and highly sensitive polymer nano-mechanical thermal analysis method for determining the melting temperature (Tm) of polymer microwires was proposed. In this method, a small-size, low-cost quartz tuning fork was used as a piezoelectric transducer to analyze the thermodynamics of polymer microwires at the nanogram level without changing its own properties. Due to the thin wire sample, which has a length of 1.2 mm and a diameter of ~5 µm, which is bridged across the prongs of the tuning fork, the nanogram-level sample greatly reduces the thermal equilibrium time for the measurement, resulting in a fast analysis for the melting temperature of the polymer sample. Compared with the traditional method, the analysis method based on the quartz enhanced conductivity spectrum (QECS) does not require annealing before measurement, which is an essential process for conventional thermal analysis to reduce the hardness, refine the grain, and eliminate the residual stress. In this work, the melting temperatures of three of the most commonly used polymers, namely polymers polymethyl methacrylate, high-density polyethylene, and disproportionated rosin, were obtained under the temperature from room temperature to >180 °C, proving the QECS method to be a useful tool for nano-mechanical thermal analysis.