Site-Directed Electrochemical Grafting for Amplified Detection of Antibody Pharmaceuticals.

Antibody pharmaceuticals have become the most popular immunotherapeutic drugs and are often administered with low serum drug dosages. Hence, the development of a highly sensitive method for the quantitative assay of antibody levels is of great importance to individualized therapy. On the basis of the dual signal amplification by the glycan-initiated site-directed electrochemical grafting of polymer chains (glyGPC), we report herein a novel strategy for the amplified electrochemical detection of antibody pharmaceuticals. The target of interest was affinity captured by a DNA aptamer ligand, and then the glycans of antibody pharmaceuticals were decorated with the alkyl halide initiators (AHIs) via boronate cross-linking, followed by the electrochemical grafting of the ferrocenyl polymer chains from the glycans of antibody pharmaceuticals through the electrochemically controlled atom transfer radical polymerization (eATRP). As the glycans can be decorated with multiple AHIs and the grafted polymer chains are composed of tens to hundreds of electroactive tags, the glyGPC-based strategy permits the dually amplified electrochemical detection of antibody pharmaceuticals. In the presence of trastuzumab (Herceptin) as the target, the glyGPC-based strategy achieved a detection limit of 71.5 pg/mL. Moreover, the developed method is highly selective, and the results of the quantitative assay of trastuzumab levels in human serum are satisfactory. Owing to its uncomplicated operation and cost-effectiveness, the glyGPC-based strategy shows great promise in the amplified electrochemical detection of antibody pharmaceuticals.

Prediction of Thermo-Mechanical Properties of 8-Harness Satin-Woven C/C Composites by Asymptotic Homogenization.

The elasticity matrix and the coefficients of thermal expansion (CTEs) of 8-harness satin-woven (8HS) carbon-fiber-reinforced carbon matrix (C/C) composites at high temperatures were obtained by the asymptotic homogenization method (AHM) and finite element method (FEM). By analyzing the microstructure of the 8HS C/C composites, a representative volume element (RVE) model considering a braided structure was established. The effects of the temperature and component volume fraction on the elasticity matrix and CTEs of the composites were investigated. The sensitivity of model parameters, including the size of RVE model and mesh sensitivity, were studied. The optimal calculation model was employed. In addition, the effects of the 4HS methods and 8HS methods on the elastic constants of the composites were compared. The temperature and variation in the carbon fiber volume fraction were found to have a significant impact on the elasticity matrix and CTEs of composite materials. At the same volume fraction of carbon fibers, some elastic coefficients of the 4HS composite material were slightly lower than those of 8HS composite material. This research affords a computational strategy for the accurate prediction of the themo-mechanical properties of satin-woven C/C composites.

Target-mediated silver deposition-based electrochemical biosensor for highly sensitive detection of human chorionic gonadotropin.

As a glycoprotein hormone, human chorionic gonadotropin (hCG) is an established marker for pregnancy test. On the basis of the target-mediated silver deposition (TSD), in this work, we report the development of an amplification-free electrochemical biosensor for the highly sensitive detection of hCG. The detection of hCG involves the use of the affinity peptide-modified electrode for hCG capture (the CGGSSPPLRINRHILTR peptide containing the hCG-binding domain of the PPLRINRHILTR sequence is used as the affinity peptide), the oxidation of the diol sites of the glycan chains on hCG hormones into aldehyde groups by NaIO4, and the deposition of silver nanoparticles (AgNPs) for the solid-state voltammetric stripping analysis. Due to the deposition of multiple AgNPs while the solid-state Ag/AgCl voltammetric process has a high signal-to-noise ratio, the TSD-based electrochemical biosensor can be applied to the highly sensitive detection of hCG without the need for signal amplification. Under optimal conditions, the stripping current increased linearly with an increasing hCG concentration over the range from 1.0 to 25 mIU/mL, with a detection limit of 0.45 mIU/mL. Owing to the high specificity of the hCG-binding peptide PPLRINRHILTR, this electrochemical hCG biosensor exhibits high selectivity. The results of the quantitative assay of hCG in urine samples at the concentrations of 25, 10, and 1.0 mIU/mL are desirable, indicating the good anti-interference capability. As the TSD-based electrochemical biosensor allows the amplification-free detection of low-abundance hCG, it is easy to use and cost-effective, showing great promise in point-of-care assay of hCG for pregnancy test.