Direct Electrochemistry of Glucose Dehydrogenase-Functionalized Polymers on a Modified Glassy Carbon Electrode and Its Molecular Recognition of Glucose.

A glucose biosensor was layer-by-layer assembled on a modified glassy carbon electrode (GCE) from a nanocomposite of NAD(P)+-dependent glucose dehydrogenase, aminated polyethylene glycol (mPEG), carboxylic acid-functionalized multi-wall carbon nanotubes (fMWCNTs), and ionic liquid (IL) composite functional polymers. The electrochemical electrode was denoted as NF/IL/GDH/mPEG-fMWCNTs/GCE. The composite polymer membranes were characterized by cyclic voltammetry, ultraviolet-visible spectrophotometry, electrochemical impedance spectroscopy, scanning electron microscopy, and transmission electron microscopy. The cyclic voltammogram of the modified electrode had a pair of well-defined quasi-reversible redox peaks with a formal potential of -61 mV (vs. Ag/AgCl) at a scan rate of 0.05 V s-1. The heterogeneous electron transfer constant (ks) of GDH on the composite functional polymer-modified GCE was 6.5 s-1. The biosensor could sensitively recognize and detect glucose linearly from 0.8 to 100 µM with a detection limit down to 0.46 µM (S/N = 3) and a sensitivity of 29.1 nA µM-1. The apparent Michaelis-Menten constant (Kmapp) of the modified electrode was 0.21 mM. The constructed electrochemical sensor was compared with the high-performance liquid chromatography method for the determination of glucose in commercially available glucose injections. The results demonstrated that the sensor was highly accurate and could be used for the rapid and quantitative determination of glucose concentration.

Construction and Biological Evaluation of Multiple Modification Hollow Mesoporous Silicone Doxorubicin Nanodrug Delivery System.

The combination of functionalized nanoparticles and chemotherapy drugs can effectively target tumor tissue, which can improve efficacy and reduce toxicity. In this article, pPeptide-PDA@HMONs-DOX nanoparticles (phosphopeptide-modified polydopamine encapsulates doxorubicin-loaded hollow mesoporous organosilica nanoparticles) were constructed that based on multiple modification hollow mesoporous organosilica nanoparticles (HMONs). The pPeptide-PDA@HMONs-DOX nanoparticles retain the biological functions of phosphorylated peptide while exhibiting biological safety that are suitable for effective drug delivery and stimulus responsive release. The degradation behaviors showed that pPeptide-PDA@HMONs-DOX has dual-responsive to drug release characteristics of pH and glutathione (GSH). In addition, the prepared pPeptide-PDA@HMONs-DOX nanoparticles have good biological safety, and their anti-tumor efficacy was significantly better than doxorubicin (DOX). This provided new research ideas for the construction of targeted nanodrug delivery systems based on mesoporous silicon. Scheme 1 The preparation of pPeptide-PDA@HMONs-DOX and the process of drug release under multiple responses. (A) Schematic diagram of the synthesis process of pPeptide-PDA@HMONs-DOX. (B) The process in which nanoparticles enter the cell and decompose and release DOX in response to pH and GSH.