Biological Interaction and Imaging of Ultrasmall Gold Nanoparticles

Ultrasmall gold nanoparticles(AuNPs)typically includes atomically precise gold nanoclusters(AuNCs)and AuNPs with a core size below 3 nm.Serving as a bridge between small molecules and traditional inorganic nanoparticles,the ultrasmall AuNPs show the unique advantages of both small molecules(e.g.,rapid distribution,renal clearance,low non-specific organ accumulation)and nanoparticles(e.g.,long blood circulation and enhanced permeability and retention effect).The emergence of ultrasmall AuNPs creates significant opportunities to address many challenges in the health field including disease diagnosis,monitoring and treatment.Since the nano–bio interaction dictates the overall biological applications of the ultrasmall AuNPs,this review elucidates the recent advances in the biological interactions and imaging of ultrasmall AuNPs.We begin with the introduction of the factors that influence the cellular interactions of ultrasmall AuNPs.We then discuss the organ interactions,especially focus on the interactions of the liver and kidneys.We further present the recent advances in the tumor interactions of ultrasmall AuNPs.In addition,the imaging performance of the ultrasmall AuNPs is summarized and discussed.Finally,we summarize this review and provide some perspective on the future research direction of the ultrasmall AuNPs,aiming to accelerate their clinical translation.

In situ self-assembly of near-infrared-emitting gold nanoparticles into body-clearable ID nanostructures with rapid lysosome escape and fast cellular excretion

The integration of strong near-infrared(NIR)emission,rapid lysosome escape,fast cellular excretion,and efficient total body clearance is highly desired for nanoparticles(NPs)to achieve synergistic functions in both molecular imaging and delivery.Herein,using a well-designed cyclopeptide(CP)that can spontaneously assem ble into controllable nanofibers a s template,a facile strategy is reported for in situ self-assembly of NIR-emitting gold NPs(AuNPs)into ordered and well-controlled one-dimensional(1D)nanostructures(AuNPs@CP)with greatly enhanced NIR emission(〜6 fold).Comparing with the unassem bled AuNPs,the AuNPs@CP are observed to enter living cells through endocytosis,escap e from lysosome rapidly,and excrete the cell fast,which shows high gene transfection efficiencies in construction of cell line with-7.5-fold overexpression of p53 protein.Furthermore,the AuNPs@CP exhibit high in vivo diffusibility and total body clearance efficiency with minimized healthy organ retention,which are also demonstrated to be good nanovectors for plasmid complementary deoxyribonucleic acid 3.1(pcDNA3.1)(+)-internal ribosome entry site(IRES)-green fluorescent protein(GFP)-p53 plasmid with efficient p53 gene over-expression in tumor site.This facile in situ strategy in fabricating highly luminescent 1D nanostructures provides a promising approach toward future translatable multifunctional nanostructures for delivering,tracking,and therapy.

Growth regulation of luminescent gold nanoparticles directed from amphiphilic block copolymers:highly-controlled nanoassemblies toward tailored in-vivo transport

The understanding of amphiphilic block copolymers(ABC)in encapsulation and transport of inorganic nanomedicines is highly desired.Still,it remains limited due to the challenges in the fabrication of nanoassemblies(NAs)with highly-controlled shape and loading of nanoparticles.Herein,through growth regulation of luminescent gold nanoparticles(Au NPs)by different reductants with ABC pluronic F127 as a template,a straightforward strategy is reported for in-situ fabrication of three wellcontrolled gold NAs(Au NAs)that display tunable shapes from spherical to elongated nanostructures and controllable surface chemistry and loading of Au NPs with distinct emissions but identical individual Au NP size.The three Au NAs exhibit tailored invivo transport behaviours:those with spherical shape and more hydrophilic surface show longer blood retention with higher tumor-targeting efficiency(~25.3%injection dose/g)and excellent long-term near-infrared tumor imaging even after 96 h postinjection.These findings provide a useful guidance in designing specific nanostructures for future nanomedicine transport.