Visual detection of serum asialohaptoglobin by plasmonic sandwich ELLSA--a new platform for cirrhosis diagnosis

130 years of Plant Lectin Research

Lectins are proteins with diverse molecular structures that share the ability to recognize and bind specifically and reversibly to carbohydrate structures without changing the carbohydrate moiety. The history of lectins started with the discovery of ricin about 130 years ago but since then our understanding of lectins has dramatically changed. Over the years the research focus was shifted from 'the characterization of carbohydrate-binding proteins' to 'understanding the biological function of lectins'. Nowadays plant lectins attract a lot of attention especially because of their potential for crop improvement and biomedical research, as well as their application as tools in glycobiology. The present review aims to give an overview of plant lectins and their applications, and how the field evolved in the last decades.

DNA-Programmed plasmonic ELISA for the ultrasensitive detection of protein biomarkers

We report a novel DNA-programmed plasmonic enzyme-linked immunosorbent assay (ELISA) for the ultrasensitive detection of protein biomarkers with the naked eye.

Visual assessment of parasitic burden in infected macrophage by plasmonic detection of leishmania specific marker RNA

Visceral leishmaniasis is a neglected tropical disease and may prove fatal if not diagnosed and treated early. The amastigotes of Leishmania donovani nest in the macrophage of human host and thus, determination of parasitic burden in the infected macrophages has been the most crucial step in diagnosis, dose determination and medical management of relapse cases of this fatal disease. Microscopic count following Giemsa staining and other morphological analysis are the classical ways vastly used in the resource stringent endemic areas. The current method introduced a high throughput, rapid, cheap, non-gel, non-PCR and nonculture based visual detection platform employing salt triggered aggregation of gold nanoparticle in presence of extracted total RNA from infected macrophages and leishmania specific oligo-nucleotide probe to determine the parasite burden in macrophages. Amastigote's small subunit ribosomal RNA (SSU rRNA, PMID 1565128) was used as the leishmania specific marker and its abundance in the total RNA extracts of infected macrophages were determined by this visual colorimetric assay.

Altered glycosylation, expression of serum haptoglobin and alpha-1-antitrypsin in chronic hepatitis C, hepatitis C induced liver cirrhosis and hepatocellular carcinoma patients

Liver cirrhosis with hepatitis C viral infection (HCV-LC) causes high risk to develop hepatocellular carcinoma (HCC). Besides diagnosis of liver cirrhosis by biochemical test, imaging techniques, assessment of structural liver damage by biopsy shows several disadvantages. Our aim was to monitor the changes in the expression level of serum proteins and their glycosylation pattern among chronic hepatitis C (HCV-CH), HCV-LC and HCC patients with respect to controls. 2D gel electrophoresis of HCV-CH, HCV-LC and HCC patients' sera showed several protein spots, which were identified by LC-MS. The change in the expression of two prominent protein spots, haptoglobin (Hp) and alpha 1-antitrypsin (AAT) was evaluated by western blot and ELISA. The changes in glycosylation pattern of these serum proteins were assayed using different lectins. Increased level of Hp and AAT was observed in HCV-LC and HCC patients' group whereas those were found to be present less in HCV-CH patient groups with respect to control as determined by ELISA using monoclonal antibodies. Decreased level of sialylation in both Hp and AAT was observed in HCV-LC and HCV-CH patients' group whereas increased level of sialylation was observed in HCC patient groups by ELISA using Sambucus nigra agglutinin. On the other hand increased level of fucosylation in two serum glycoproteins was observed in HCV-LC and HCC patients' group using Lens culinarris agglutinin. High glycan branching was found in HCV-LC and HCC patient groups in Hp but not in HCV-CH as determined by Datura stramonium agglutinin. However, there was no such change observed in glycan branching in AAT of HCV-CH and HCV-LC patients' groups, to the contrary high glycan branching was observed in HCC patients' group. Increased level of exposed galactose in both serum proteins was observed in both HCC patients' group as determined by Ricinus communis agglutinin. The present glycoproteomics study could predict the progression of HCV-CH, HCV-LC and HCC without the need of liver biopsy.

Plasmonic-ELISA: expanding horizons

Convergence of localized surface plasmon resonance of metal nanoparticles with classical ELISA has emerged as a new class of immunoassays, i.e. plasmonic ELISA, enabling biocatalysis mediated ultrasensitive naked-eye detection of disease biomarkers.