Ultrasound wave-mediated enzyme-linked immunosorbent assay technique

Abstract

With the increasing burden of infectious diseases, it has become important to develop a rapid ELISA that could facilitate early diagnosis. Herein, we have shown that ultrasound waves can dramatically reduce the ELISA timing without losing its specificity or sensitivity. Ultrasound-mediated ELISA was best achieved on an activated microtiter plate which was able to covalently bind antigen or antibody in 10 min when subjected to ultrasound waves in a sonicator bath having a temperature of 37 °C, operating at a frequency of 40 KHz and an output power of 120 W. Blocking, antibody binding and secondary antibody–enzyme conjugate binding were also accomplished in 10 min each in the sonicator bath under similar conditions. The validation of SELISA method was demonstrated by detecting IgE in allergic patient's sera. Total IgE detection by 40 min-SELISA method gives similar absorbance value to that obtained by 20 h conventional or 3 h-HELISA procedure. As SELISA method can detect IgE even at the serum dilution of 1/50 (v/v) on photoactivated surface it could be significantly useful to confirm false negative cases. The inhibition assay ruled out the possibility of any cross reactivity or non-specific binding. As SELISA procedure is sensitive, specific and reproducible (intra- and inter-assay CVs were 9.65% and 8.47%) it could be an excellent alternative to conventional ELISA or HELISA procedures.