Open Access

A lateral flow immunoassay (LFIA) using latex particles labeled with antibody to BSAclarithromycin (CLA) was developed for the rapid simultaneous group determination of six macrolide antibiotics. Optimization of antigen spotting on the membrane and latex probe loading allowed improving visual detectability (vLOD) 100 times, which was 1, 1, 10, 10, 50, and 1000 ng/mL for CLA, roxithromycin, erythromycin, dirithromycin, azithromycin, and oleandomycin in buffer, respectively. The calculated limits of instrumental detection (cLOD) were respectively 0.12, 0.15, 1.4, 2.1, 2.4, and 3.3 ng/mL. To avoid a strong influence of breast milk of a very diverse and variable composition, a sample pretreatment is proposed. The six macrolides mentioned can be visually detected in breast milk after 20 minutes pretreatment at concentrations of 10-1000 ng / ml or instrumentally with cLOD of 4.0, 2.5, 30, 42, 42 and 180 ng/mL. The recovery rate from the spiked samples carried out using a strip scanner device ranged from 71% to 110%, and precision expressed as relative standard deviation was between 3-14%. The described rapid on-site diagnostic assay format can be useful for monitoring the content of antibiotics in breast milk during macrolide treatment to ensure safe breastfeeding of infants.

We report a novel and innovative electrochemical paper-based immunocapture assay (EPIA) to address the need for ultrasensitive detection of emerging pollutants without regulatory status and whose effects on environment and human health are not completely yet understood. In particular, we present the application of this system toward highly sensitive detection of the emerging pollutant ethinyl estradiol (EE2). The EPIA approach is based on the use of paper microzones modified with silica nanoparticles (SNs) and anti-EE2 specific antibodies for capture and preconcentration of EE2 from river water samples. After the preconcentration procedure, the paper microzones are placed onto a screen-printed carbon electrode modified with electrochemically reduced graphene (RG). The bound EE2 is subsequently desorbed adding a diluted solution of sulfuric acid on the paper microzones. Finally, recovered EE2 is electrochemically detected by OSWV. The proposed novel methodology showed an appropriate LOD and linear range for the quantification of EE2 for water samples with different origins. The nonsophisticated equipment required, the adequate recovery values obtained (from 97% to 104%, with a RSD less than 4.9%), and the appropriate LOD and linear range value (0.1 ng L−1 and 0.5−120 ng L−1, respectively) achieved by our immunocapture sensor present significant analytical figures of merit, particularly when the routine quantification of EE2 is considered. In addition, our System was based on electrochemical paper-based technology, which allows obtainment of portable, easy-to-use, inexpensive, and disposable devices. The EPIA can also serve as a general-purpose immunoassay platform applicable to quantitation of other drugs and emerging pollutants in environmental samples.

In this work, we report an electrochemical immunosensor to detect ethinylestradiol in water samples, using electrochemical impedance spectroscopy (EIS) as a detection technique. For the development of this immunosensor, the direct modification of the working electrode of a screen-printed carbon electrode was carried out. First, to reduce the resistance of the electrode, electroreduced graphene was incorporated on the surface. Second, a porous gold structure was electrodeposited on reduced graphene by electrodeposition and the dynamic hydrogen bubble template assisted method. Thus, a marked increase in surface area was obtained for anti-EE2 antibodies immobilization. Subsequently, the specific anti-EE2 antibodies were covalently immobilized using α-lipoic acid for attaching them to the gold surface. The electrode modified with the antibodies was incubated for 30 min in the samples containing EE2, producing the specific Antigen antibody binding. As the charge transfer resistance of a redox probe in the electrode surface is governed by the surface blocking effects, the charge transfer resistance was related to the amount of EE2 captured to realize a quantitative determination. For this, the EIS measurements were performed in a 4 mM [Fe(CN)6]4−/3− solution in 0.1 M KCl. The obtained Nyquist diagrams were adjusted using the Randles circuit as an equivalent circuit to obtain the corresponding resistances. The developed methodology showed good selectivity, precision, and sensitivity; although the LOD obtained was higher than those presented in other published articles, it turned out to be an alternative that allows the determination of ethinylestradiol using a simple disposable electrode.

The toxicity induced in non-target organisms by pharmaceutical drugs has been the focus of several studies. In the aquatic environment, most of the studies have been devoted to fish and bivalves, while little is known on the impacts induced in polychaetes. The present study evaluated the impacts of carbamazepine and caffeine on the regenerative capacity of Diopatra neapolitana, a polychaete species with high ecological and economic relevance. Under laboratory controlled conditions polychaetes were exposed, during 28 days, to carbamazepine (Ctl-0.0; 0.3; 3.0; 6.0; 9.0 mg/L) and caffeine (Ctl-0.0; 0.5; 3.0; 18.0 mg/L). During the experiment, at days 11, 18, 25, 32, 39 and 46 after amputation, for each specimen, the percentage of the body width regenerated was determined and the number of new segments was counted. The regenerative capacity was assessed considering the number of days needed to achieve full regeneration and the total number of new segments. The obtained results revealed that with the increase of drugs concentrations organisms regenerated less new segments and took longer to completely regenerate.

In the last decade studies have reported the presence of several pharmaceutical drugs in aquatic environments worldwide and an increasing effort has been done to understand the impacts induced on wildlife. Among the most abundant drugs in the environment is caffeine, which has been reported as an effective chemical anthropogenic marker. However, as for the majority of pharmaceuticals, scarce information is available on the adverse effects of caffeine on marine benthic organisms, namely polychaetes which are the most abundant group of organisms in several aquatic ecossystems. Thus, the present study aimed to evaluate the biochemical alterations induced by environmentally relevant concentrations of caffeine on the polychaete species Diopatra neapolitana and Arenicola marina. The results obtained demonstrated that after 28 days exposure oxidative stress was induced in both species, especially noticed in A. marina, resulting from the incapacity of antioxidant and biotransformation enzymes to prevent cells from lipid peroxidation. The present study further revealed that D. neapolitana used glycogen and proteins as energy to develop defense mechanisms while in A. marina these reserves were maintained independently on the exposure concentration, reinforcing the low capacity of this species to fight against oxidative stress.