pH-responsive metal nanoparticles as high contrast theranostic agents for selective imaging and synergistic cancer therapy

The low signal-to-noise ratio(S/N)and single functionality of fluorescence imaging agents have limited their practical applications.Bright two-photon excitation(2PE)imaging probes are highly desirable in vivo with larger imaging depth,minor autofluorescence background,and less photodamage.Herein,we developed responsive aggregated gold nanoparticles(Au NPs)as high contrast 2PE imaging agents,capable of emitting red fluorescence upon excitation of near-infrared(NIR)laser and possessing a high signal-to-noise ratio(S/N of 2,475).By forming aggregates in situ inside tumor tissue,doxorubicin hydrochloride(DOX)-loaded mix-charged gold nanoparticles(DOX-MC-Au NPs)were utilized to act as selective fluorescence imaging probes and precise therapy agents.These high-contrast theranostic agents offer a promising potential for precise cancer imaging and therapy,which might open a new venue to multifunctional and noninvasive theranostics.

Dual microenvironmental parameter-responsive lysosome-targeting carbon dots for the high contrast discrimination of a broad spectrum of cancer cells

The development of new carbon dots(CDs)for fluorescence-based cancer diagnosis has recently attracted extensive attention.Diagnosis methods based on ligand-receptor fluorescence suffer from the heterogeneity of receptor expression.Changes in the microenvironments of cancer cells provide opportunities for accurate and broad-spectrum cancer diagnosis.The lysosomes in cancer cells have lower polarity and higher viscosity than normal cells.Based on these two key microenvironmental parameters,dual-responsive CDs with inherent lysosome-targeting ability were synthesized via one-step hydrothermal treatment.The CDs exhibit many advantageous properties including facile synthesis,good water solubility,pH-independent emission,excellent photostability,good biocompatibility,and wash-free imaging ability.The CDs were successfully employed in the fluorescence-based discrimination of a broad spectrum of cancer cells from normal cells with high contrast.The CDs are promising candidates for use in the field of cancer diagnosis.