A dual-functional membrane for bisphenol A enrichment and resonance amplification by surface-enhanced Raman scattering

Bisphenol A （BPA） was one of the environmental hormones that would cause endocrine and metabolic disorders in human or wildlife. This paper proposed a method to detect the trace amounts of BPA in water samples by fully utilizing the enrichment and resonance amplification functions of a new dual-functional membrane. In this work, gold nanoparticles （AuNPs） modified by 3-amino-5-mercapto-1,2,4-triazole （AMT） were embedded in nylon66 membrane to produce a dual-functional membrane which could carry out sample enrichment by capturing BPA molecules from water and achieve resonance amplification by connecting BPA to the surfaces of AuNPs. By designing an automatic sampler for large-volume enrichment, the SERS enhancement factor （EF） of the method was further improved to 1.2 × 105. The present method had been successfully applied to detect BPA in drinking water and environmental water by SERS with the detection limit of 0.012 μg/L. It had the potential for on-site detecting of BPA in various water samples.

Enrichment of Cd^(2＋) from water with a calcium alginate hydrogel filtration membrane

A new method was developed for effective enrichment of Cd2+ ions from water with a calcium alginate(CaAlg) hydrogel filtration membrane. First, the CaAlg hydrogel filtration membrane was prepared without a pore-forming agent. This membrane was used to remove Cd^(2+) via ion exchange with Ca^(2+), and the Cd^(2+) was preserved in the CaAlg hydrogel. Then, the CaAlg hydrogel containing Cd^(2+) was soaked in a sodium citrate solution, and the hydrogel was fully dissolved. The removal rate of the CaAlg filtration membrane reached almost 100% within 120 min when the Cd^(2+) concentration was under 1 mg/L. Factors affecting the removal rate were investigated, such as NaAlg concentration, operating pressure, operating time and the initial concentration of Cd^(2+). The effects of initial Cd^(2+) concentration, pressure and filtration time on the enrichment factor were also investigated. The results show that the enrichment factor reached 87.3 when the pressure was 0.18 MPa and the filtration time was 240 min. Different enrichment factors could be achieved by adjusting the operating pressure and filtration time.

Progress in DNA Aptamers as Recognition Components for Protein Functional Regulation

Proteins play a central role in all domains of life,and precise regulation of their activity is essential for understanding the related biological processes and therapeutic functions.Nucleic acid aptamers,the molecular recognition components derived from systematic evolution of ligands by exponential enrichment(SELEX),can specifically identify proteins with antibody-like recognition characteristics and help to regulate their activity.This minireview covers the SELEX-based selection of protein-binding aptamers,membrane protein analytical techniques based on aptamer-mediated target recognition,aptamer-mediated functional regulation of proteins,including membrane receptors and non-membrane proteins(thrombin as a model),as well as the potential challenges and prospects regarding aptamer-mediated protein manipulation,aiming to supply some useful information for researchers in this field.