Recent advances of semiconducting polymer nanoparticles in in vivo molecular imaging

Abstract

Semiconducting polymer nanoparticles (SPNs) emerge as attractive molecular imaging nanoagents in living animals because of their excellent optical properties including large absorption coefficients, tunable optical properties and controllable dimensions, high photostability, and the use of organic and biologically inert components without toxic metals. This review summarizes the recent advances of these new organic nanoparticles in in vivo molecular imaging. The in vivo biocompatibility of SPNs is discussed first in details, followed by examples of their applications ranging from sentinel lymph node mapping and tumor imaging to long-term cell tracking, to drug toxicity and bacterial infection imaging for fluorescence, bioluminescence, chemiluminescence and photoacoustic imaging in living animals. The utility of SPNs for designing smart activatable probes for real-time in vivo imaging is also discussed.

Light‐Induced PEGylation and Functionalization of Semiconductor Polymer Dots

“…Polyfluorene-based p-conjugated polymer nanoparticles with ultrabright fluorescenceh ave been successfully applied for cell labeling and tracking, [18,19] bioorthogonal tagging, [20] and in vivo tumort argeting. [21,22] Accordingly,w echoose polyfluorene polymers to modify their side chains with oxetane groups.M oreover,P EG has been approved by the U.S. Food and Drug Administration for clinicala pplicationsi nv arious biomedicala reas owing to its non-toxicity and non-immunogenicity.P EGylated nanoparticles exhibited important characteristics for in vivo applications such as the increased blood circulation lifetimea sw ell as the decreased clearance by the body's reticuloendothelial system.…”

Silica passivated conjugated polymer nanoparticles for biological imaging applications

“…They have bright fluorescence, excellent photo-stability and narrow emission 11 . However, as they are normally composed of heavy metals, such as cadmium and selenium, there is a serious concern about the toxicity of the nanoparticles to cells 12,13,14. There is another set of fluorescent particles that have been studied, composed of conjugated polymers (CPs) which have gained growing attention due to their attractive optical properties such as bright photoluminescence and photo-stability [15][16][17][18][19] . CPs are organic semiconductors with backbone of alternating multiple and single bonds which exhibit efficient coupling between optoelectronic segments; electrons can delocalise allowing for excitons to diffuse efficiently throughout the polymer chain 20,21 .…”

“…CPs are organic semiconductors with backbone of alternating multiple and single bonds which exhibit efficient coupling between optoelectronic segments; electrons can delocalise allowing for excitons to diffuse efficiently throughout the polymer chain 20,21 . There are a number of advantages of conjugated polymer nanoparticles (CPNs) over QDs, including their ease of processing, large absorption coefficients, tuneable optical properties, controllable dimensions and biologically inert components circumventing the issue of heavy metal toxicity of QDs 19,22 . It is also possible to obtain conjugated polymers commercially in a range of colours that allows the potential for tuneable emission.…”

Editor’s choice: recent research highlights from the International Journal of Nanomedicine

“…26 It is therefore pathophysiologically challenging to identify functionally relevant target genes and pathways on the basis of dysregulated gene expression profiles in tumor cell types. Common approaches to study target genes and function in cancer involve experimental complexities of clinically important gene expression evaluation in cell lines and mouse models.…”