An Intein-mediated Stimuli-responsive Nanocarrier

Stimuli-responsive drug delivery system that is sensitive to specific environment triggers and delivers drugs in dosage-, temporal- and spatial- controlled fashions has recently received tremendous attention, particularly in the field of nanomedicine. Such stimuli-responsive delivery(also termed “switch on/off”) can prevent premature release, minimize undesirable or toxic side effects, and enhance therapeutic efficacy.In order to develop new strategies for controllable drug release, here we report our attempt to establish a novel protein/peptide delivery platform mediated by intein, a biological intelligent element that can self-cleavaged in response to relatively high temperature, with AuNPs as the heater via photothermal conversion upon laser irritation. Through gene fusion and rational design, green fluorescent protein and intein were expressed as a recombinant protein with an additional gold binding tag, which can conjugate to AuNPs via high-affinity gold-sulfur bonding. As demonstrated by SDS-PAGE, native agarose gel electrophoresis and fluorescence spectrometry, the fused protein has been efficiently loaded onto the AuNPs surface and the cargo can be released responsively by temperature stimulation. In addition, after cargo release, the intein can still stay on the AuNPs surface, preserving the good biocompatibility of the designed nanocarrier.Based on the intein platform, this study went further to provide a method to investigate the orientation of proteins loaded on nanoparticles, a fundamental question in fabricating protein-nanoparticle complexs. Protein surface properties have been found to play an important role in determining orientations of proteins on AuNPs surface.In summary, this study have constructed a novel temperature-responsive nanocarrier characterized by controllable release through photo-thermal conversion and put forward a idea for analyzing the orientation of proteins on nanoparticle surface.