Cell-penetrating peptides: 20 years later, where do we stand?
Keywords: CPP, cell-penetrating peptide; MALDI, matrix-assisted laser desorption; TOF, time of flight; MS, mass spectrometry; ON, oligonucleotide; EGFP, enhanced green fluorescent protein; CHO, Chinese hamster ovary; FITC, fluorescein isothiocyanate; CS, chondroiti