Energy efficiency and balancing is one of the primary challenges for wireless sensor networks (WSNs) since the tiny sensor nodes cannot be easily recharged once they are deployed. Up to now, many energy efficient routing algorithms or protocols have been proposed with techniques like clustering, data aggregation and location tracking etc. However, many of them aim to minimize parameters like total energy consumption, latency etc., which cause hotspot nodes and partitioned network due to the overuse of certain nodes. In this paper, a Distance-based Energy Aware Routing (DEAR) algorithm is proposed to ensure energy efficiency and energy balancing based on theoretical analysis of different energy and traffic models. During the routing process, we consider individual distance as the primary parameter in order to adjust and equalize the energy consumption among involved sensors. The residual energy is also considered as a secondary factor. In this way, all the intermediate nodes will consume their energy at similar rate, which maximizes network lifetime. Simulation results show that the DEAR algorithm can reduce and balance the energy consumption for all sensor nodes so network lifetime is greatly prolonged compared to other routing algorithms.

Carbon disulfide (CS 2 ) can spontaneously react with amine groups to form dithiocarbamates on gold surface, providing the possibility to immobilize some compounds with primary or secondary amine groups in one step. Using this principle, an immunosensor interface prepared for immunoglobulin G (IgG) sensing surface toward anti-IgG has been fabricated for the first time by simply immersing gold slides into a mixed aqueous solution of CS 2 and protein A, followed by incubation in immunoglobulin G solution. The reaction between CS 2 and protein A has been followed by UV−vis spectroscopy, whereas cyclic voltammetry has been employed in the characterization of the modified gold surface with CS 2 and protein A, both methods indicating that protein A immobilization is implemented by CS 2 . Conventional ellipsometry, atomic force microscopy (AFM), as well as surface plasmon resonance (SPR) have been used to evaluate the specific binding of protein A with IgG and IgG with anti-IgG, revealing that IgG is specifically captured to form the biosensing interface, maintaining its bioactivity. Compared to direct adsorption of IgG on the gold surface, the IgG sensing surface constructed of CS 2 and protein A is far more sensitive to capture anti-IgG as its target molecule. In addition, the modified surface is proven to have good capability to inhibit nonspecific adsorption, as supported by control experiments using lysozyme and BSA. To conclude, antibody immobilization using this one-step method has potential as a simple and convenient surface modification approach for immunosensor development.

A biosensor based on imaging ellipsometry (BIE) has been developed and validated in 169 patients for detecting five markers of hepatitis B virus (HBV) infection. The methodology has been established to pave the way for clinical diagnosis, including ligand screening, determination of the sensitivity, set-up of cut-off values (CoVs) and comparison with other clinical methods. A matrix assay method was established for ligand screening. The CoVs of HBV markers were derived with the help of receiver operating characteristic curves. Enzyme-linked immunosorbent assay (ELISA) was the reference method. Ligands with high bioactivity were selected and sensitivities of 1 ng/mL and 1 IU/mL for hepatitis B surface antigen (HBsAg) and surface antibody (anti-HBs) were obtained respectively. The CoVs of HBsAg, anti-HBs, hepatitis B e antigen, hepatitis B e antibody and core antibody were as follows: 15%, 18%, 15%, 20% and 15%, respectively, which were the percentages over the values of corresponding ligand controls. BIE can simultaneously detect up to five markers within 1 h with results in acceptable agreement with ELISA, and thus shows a potential for diagnosing hepatitis B with high throughput.