A double-antibody sandwich ELISA based on the porcine circovirus type 2 (PCV2) propagated in cell culture for antibody detection

Development of a Gold Nanoparticle-Based ELISA for Detection of PCV2

In this new methodology, plasmonic ELISA (pELISA) was used to detect Circovirus porcine2 (PCV2) in serum samples without the need for plate reading equipment. This process occurs by adapting the conventional ELISA test with gold nanoparticles (AuNPs) to promote a color change on the plate and quickly identify this difference with the naked eye, generating a dark purple-gray hue when the samples are positive and red when the samples are negative. The technique demonstrated high efficiency in detecting samples with a viral load ≥ 5 log10 copies/mL. Plasmonic ELISA offers user-friendly, cost-effective, and reliable characteristics, making it a valuable tool for PCV2 diagnosis and potentially adaptable for other pathogen detection applications.

Colorimetric Kit for Rapid Porcine Circovirus 2 (PCV-2) Diagnosis

The aim of the current study is to present a low-cost and easy-to-interpret colorimetric kit used to diagnose porcine circovirus 2 (PCV-2) to the naked eye, without any specific equipment. The aforementioned kit used as base hybrid nanoparticles resulting from the merge of surface active maghemite nanoparticles and gold nanoparticles, based on the deposition of specific PCV-2 antibodies on their surface through covalent bonds. In total, 10 negative and 40 positive samples (≥102 DNA copies/µL of serum) confirmed by qPCR technique were tested. PCV-1 virus, adenovirus, and parvovirus samples were tested as interferents to rule out likely false-positive results. Positive samples showed purple color when they were added to the complex, whereas negative samples showed red color; they were visible to the naked eye. The entire color-change process took place approximately 1 min after the analyzed samples were added to the complex. They were tested at different dilutions, namely pure, 1:10, 1:100, 1:1000, and 1:10,000. Localized surface plasmon resonance (LSPR) and transmission electron microscopy (TEM) images were generated to validate the experiment. This new real-time PCV-2 diagnostic methodology emerged as simple and economic alternative to traditional tests since the final price of the kit is USD 4.00.

A Methodology for Porcine Circovirus 2 (PCV-2) Quantification Based on Gold Nanoparticles

The aim of the current study is to introduce a methodology aimed at producing a biosensor that uses gold nanoparticles (AuNPs) to detect porcine circovirus 2 (PCV-2). This biosensor was based on AuNPs, which were modified with self-assembled monolayers (SAMs) and antibodies. The AuNPs’ surface and virus modification process applied to enable antibody binding was accompanied by localized surface plasmon resonance (LSPR), surface plasmon resonance (SPR), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). Virus quantification was possible by the light absorption difference in the spectrum at concentrations of 10⁵, 10⁶, 10⁷, 10⁸, and 10⁹ DNA copies/mL PCV-2 in relation to quantitative PCR (qPCR), with an R² value >0.98. The visualization of colorimetric changes in the different PCV-2 concentrations was possible without the use of equipment. The biosensor production methodology presented reproducibility and specificity, as well as easy synthesis and low cost. An enhanced version of it may be used in the future to replace traditional tests such as PCR.

Improvement of memory deficits in the rat model of Alzheimer's disease by erythropoietin-loaded solid lipid nanoparticles

Erythropoietin (EPO), a hematopoietic factor, is one of the promising neuroprotective candidates in neurodegenerative disorders such as Alzheimer's disease (AD). Due to the high molecular weight, hydrophilicity and rapid clearance from circulation, EPO could not completely pass the blood-brain barrier in the case of systemic administration. To overcome this limitation, EPO-loaded Solid Lipid Nanoparticle (EPO-SLN) was developed in this study using a double emulsion solvent evaporation method (W₁/O/W₂). Glycerin monostearate (GMS), span®80/span®60, Dichloromethane (DCM) and tween®80 were chosen as lipid, internal phase surfactants, solvent, and external aqueous phase surfactant, respectively. After physicochemical evaluations, the effect of EPO-SLN on the beta-amyloid-induced AD-like animal model was investigated. In vivo evaluations, it was demonstrated that the memory was significantly restored in cognitive deficit rats treated with EPO-SLN compared to the rats treated with native drug using the Morris water maze test. In addition, EPO-SLN reduced the oxidative stress, ADP/ATP ratio, and beta-amyloid plaque deposition in the hippocampus more effectively than the free EPO. Hence, the designed SLN can be regarded as a promising system for safe and effective delivery of EPO in the AD.

Insulin: a review of analytical methods

Insulin is an important polypeptide hormone that regulates carbohydrate metabolism.