Unveiling the underpinnings of various non-conventional ELISA variants: a review article

ABSTRACT

Introduction

Enzyme-linked immunosorbent assay (ELISA) is a key bio-analytical technique used for the detection of a large array of antigenic substances of scientific, clinical, food safety, and environmental importance. The assay primarily involves capturing and detecting target analytes using specific antigen-antibody interactions. The wide usage of ELISA results from its high specificity and reproducibility. Notwithstanding, the conventional microwell plate-based format of ELISA has some major drawbacks, such as long assay time (4–18 h), large sample volumes requirement (100–200 μL), lack of multiplicity, and burdensome procedures that limit its utility in rapid and affordable diagnostics.

Areas covered

Here, we reviewed microfluidic-ELISA, paper-ELISA, aptamer-ELISA, and those based on novel incubation such as heat-ELISA, pressure-ELISA, microwave-ELISA, and sound-ELISA. Further, the current trends and future prospects of these ELISA protocols in clinical diagnostics are discussed.

Expert opinion

The reviewed non-conventional ELISA formats are relatively rapid, require low reagent volumes, are multiplexable, and could be performed in a low-cost setup. In our opinion, these non-conventional variants of ELISA are on a par with the conventional format for clinical diagnostics and fundamental biological research and hold added clinical translational potential for quick, inexpensive, and convenient measurements.

KEYWORDS:

• Microfluidic-ELISA
• paper-ELISA
• aptamer-ELISA
• heat-ELISA
• pressure-ELISA
• microwave-ELISA
• sound-ELISA

Article highlights

• An overview of various non-conventional formats of ELISA is provided.

• Microfluidic, paper, aptamer, and novel incubation-based ELISA are detailed.

• Strengths and limitations of these ELISA formats are discussed.

• Comparison of assay time of various ELISA formats is provided.

Acknowledgments

The authors would like to thank Science and Engineering Research Board (SERB)for assisting in the study. Authors are immensely grateful to Prof. Pradip Nahar for his contribution to the field. They would also like to thank Mrs. Kamini Arya for her help in data collection.

Declaration of interests

The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewers disclosure

Peer reviewers on this manuscript have no relevant financial relationships or otherwise to disclose.

Additional information

Funding

This article was funded by Science and Engineering Research Board, India (Grant no ECR/2017/003179).