title: Single-domain antibody based thermally stable electrochemical immunosensor.
abstract: Conventional monoclonal and polyclonal antibodies are sensitive to changes in environmental factors such as temperature, pH, humidity, etc. This limits the current cost-effective and portable electrochemical immunosensors in harsh environments. Using Ricin Chain-A, a naturally occurring toxin, as a model analyte we report fabrication of a thermally stable electrochemical immunosensor. Single-domain antibodies (sdAb) or nanobodies have been employed as recognition elements for direct detection of Ricin at temperatures great than 4°C. Immunosensor fabricated using the conventional Ricin monoclonal and polyclonal antibodies have also been demonstrated for comparison. In the case of sdAb immunosensor, Ricin was detected in a linear range of 1log(fg/mL)-1log(μg/mL) with a sensitivity of 0.07μA/log(g/mL)/cm(2) using cyclic voltammetry. The fabricated miniaturized sensors have demonstrated higher shelf life and stability at temperatures up to 40°C. Therefore these electrochemical sensors can be integrated as a part of a portable device for point-of-care immunosensing.
authors.affiliation: BioMEMS and Microsystems Laboratory, Department of Electrical and Computer Engineering, Florida International University, Miami, FL 33174, United States.
authors.forename: Aparajita
authors.initials: A
authors.lastname: Singh
authors.affiliation: BioMEMS and Microsystems Laboratory, Department of Electrical and Computer Engineering, Florida International University, Miami, FL 33174, United States.
authors.forename: Syed Khalid
authors.initials: SK
authors.lastname: Pasha
authors.affiliation: BioMEMS and Microsystems Laboratory, Department of Electrical and Computer Engineering, Florida International University, Miami, FL 33174, United States.
authors.forename: Pandiaraj
authors.initials: P
authors.lastname: Manickam
authors.affiliation: BioMEMS and Microsystems Laboratory, Department of Electrical and Computer Engineering, Florida International University, Miami, FL 33174, United States. Electronic address: sbhansa@fiu.edu.
authors.forename: Shekhar
authors.initials: S
authors.lastname: Bhansali
mesh_terms: D055910:Antibodies, Immobilized / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation; D002619:Chemical Warfare Agents / Q000032:analysis*; D055664:Electrochemical Techniques / Q000295:instrumentation*; D004867:Equipment Design; D007118:Immunoassay / Q000295:instrumentation*; D019095:Point-of-Care Systems; D055550:Protein Stability; D012276:Ricin / Q000032:analysis*; D061905:Single-Domain Antibodies / Q000737:chemistry*; D013696:Temperature
chemical_list: D055910:Antibodies, Immobilized; D002619:Chemical Warfare Agents; D061905:Single-Domain Antibodies; D012276:Ricin
keywords: Electrochemical sensor; Immunosensor; Ricin; Single-domain antibody; Thermal-stability