Abstract
Efficient intracellular delivery is crucial for biotherapeutics, such as proteins, oligonucleotides, and CRISPR/Cas9 gene-editing systems, to achieve their efficacy. Despite the great efforts of developing new intracellular delivery carriers, the lack of straightforward methods for intracellular delivery quantification limits further development in this area. Herein, we designed a simple and versatile bioorthogonal luminescent reaction (BioLure assay) to analyze intracellular delivery. Our results suggest that BioLure can be used to estimate the amount of intracellularly delivered molecules after electroporation, and the estimation by BioLure is in good correlation with the results from complementary methods. Furthermore, we used BioLure assay to correlate the intracellularly-delivered RNase A amount with its tumoricidal activity. Overall, BioLure is a versatile tool for understanding the intracellular delivery process on live cells, and establishing the link between the cytosolic concentration of intracellularly-delivered biotherapeutics and their therapeutic efficacy.