Stimuli-responsive polypeptide nanogels loaded with α1-antitrypsin for inhibition of inflammatory mediator trypsin

A new type of hydrophilic, biocompatible, and biodegradable polypeptide nanogel depots loaded with natural serine protease inhibitor α1-antitrypsin (AAT) was applied for inhibition of inflammatory mediator trypsin. Further, poly[N5-(2-hydroxyethyl)-L-glutamine-ran-N5-propargyl-L-glutamine-ran-N5-(6-aminohexyl)-L-glutamine]-ran-N5-[2-(4-hydroxyphenyl)ethyl)-L-glutamine] (PHEG-Tyr) and Nα-L-Lysine-grafted α,β-poly[(2-propyne)-D,L-aspartamide-ran-(2-hydroxyethyl)-DL-aspartamide-ran-(2-(4-hydroxyphenyl)ethyl)-DL-aspartamide] (Nα-Lys-NG) nanogels were prepared by HRP/H2O2-mediated crosslinking in inverse miniemulsions with pH and temperature-stimuli responsive behavior confirmed by dynamic light scattering and zeta potential measurements. The loading capacity of PHEG-Tyr and Nα-Lys-NG nanogels and their release profiles were firstly optimized with bovine serum albumin (BSA) and then used for loading and release of AAT. PHEG-Tyr and Nα-Lys-NG nanogels showed different loading capacities for AAT with the maximum (20 %) achieved with Nα-Lys-NG nanogel. In both cases, the nanogels depots demonstrated a burst release of AAT during 6 h, which could be favorable for quick inhibition of trypsin. A consequent pilot in vitro inhibition study revealed that both PHEG-Tyr and Nα-Lys-NG nanogels loaded with AAT successfully inhibited the enzymatic activity of trypsin. Furthermore, the inhibitory efficiency of the AAT-loaded nanogels was higher than that of AAT itself, indicating that the negatively charged polypeptide nanogels enhance the inhibitory function of AAT loaded in the nanogel depots.

Effect of 1-Acetyl-1H-Benzotriazole on Corrosion of Mild Steel in 1M HCl

The corrosion inhibition study of 1-acetyl-1H-benzotriazole (ABTZ) on mild steel in 1M HCl solution has been investigated using different techniques like weight loss, open circuit potential (OCP), and potentiodynamic polarization. Results showed that ABTZ inhibited mild steel corrosion in acid solution and indicated that the inhibition efficiencies increased with the increase in inhibitor concentration. The polarization curves revealed that the studied compound behaved as a mixed-type of inhibitor. The adsorption of the inhibitor on the surface of mild steel in the corrosive environment followed the Langmuir isotherm. The presence of thin film formed due to adsorption of ABTZ on mild steel surface is further confirmed by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX).

A Laboratory Corrosion Inhibition Study of Carbon Steel Using 2-Mercaptobenzothiazole (MBT) under Post-combustion CO2 Capture Conditions

Corrosion mitigation is an important aspect of amine-based post-combustion carbon dioxide (CO2) capture operations due to the desire to use less expensive but corrosion-vulnerable materials such as low carbon steels in the construction of a capture system. In this study, the corrosion behavior of A106 (grade B) carbon steel with an in-house proprietary amine-based solvent was investigated in a laboratory environment at 80 °C using an organic corrosion inhibitor, 2 Mercaptobenzothiazole (MBT). The corrosion inhibition mechanism was interpreted by electrochemical methods and surface analyses. The results revealed that the corrosion rates of carbon steel were significantly retarded using MBT. The critical inhibitor concentration was determined to be lie between 10 to 50 ppm under the tested conditions.