Search

Current therapeutics for glioblastoma multiforme (GBM) treatment are unsatisfactory due to their limited ability to control the progression from tumour margins. In this work, organic nanoparticles (NPs) are synthesized by co-encapsulating a fluorogen with aggregation-induced emission to generate a bright red emission for imaging and a semiconducting polymer to offer NIR absorption for photothermal therapy. The NPs are further modified with different ratios of two targeting ligands, folate and cRGD peptide. The best ratio that performs specific and efficient GBM targeting is screened out through in vitro and ex vivo fluorescence imaging analysis. The NPs with an FA to cRGD ratio of 25 : 75 exhibit superior ability to target GBM cells in vitro and also show efficient accumulation at the GBM margin and in the tumour interior after in vivo administration. The progression of GBM can be greatly suppressed through photothermal therapy, which provides a simple but promising strategy for GBM treatment.

Stem-cell based therapy is an emerging therapeutic approach for ischemic stroke treatment. Bone marrow stromal cells (BMSCs) are in common use as a cell source for stem cell therapy and show promising therapeutic outcomes for stroke treatment. One challenge is to develop a reliable tracking strategy to monitor the fate of BMSCs and assess their therapeutic effects in order to improve the success rate of such treatment. Herein, TPEEP, a fluorogen with aggregation-induced emission characteristics and near-infrared emission are designed and synthesized and further fabricated into organic nanoparticles (NPs). The obtained NPs show high fluorescence quantum yield, low cytotoxicity with good physical and photostability, which display excellent tracking performance of BMSCs in vitro and in vivo. Using a rat photothrombotic ischemia model as an example, the NP-labeled BMSCs are able to migrate to the stroke lesion site to yield bright red fluorescence. Immunofluorescence staining shows that the NP labeling does not affect the normal function of BMSCs, proving their good biocompatibility in vivo. These merits make TPEEP NP a potential cell tracker to evaluate the fate of BMSCs in cell therapy.

As conjugated polymer nanoparticles (CPNs) have attracted growing interest as photoacoustic (PA) imaging contrast agents, revelation of the relationship between the molecular structure of conjugated polymers and PA property is highly in demand. Here, three donor-acceptor-structured conjugated polymer analogs are designed, where only a single heteroatom of acceptor units changes from oxygen to sulfur to selenium, allowing for systematic investigation of the molecular structure-PA property relationship. The absorption and PA spectra of these CPNs can be facilely tuned by changing the heteroatoms of the acceptor units. Moreover, the absorption coefficient, and in turn the PA signal intensity, decreases when the heteroatom changes from oxygen to sulfur to selenium. As these CPNs exhibit weak fluorescence and similar photothermal conversion efficiency (≈70%), their PA intensities are approximately proportional to their absorption coefficients. The in vivo brain vasculature imaging in this study also demonstrates this trend. This study provides a simple but efficient strategy to manipulate the PA properties of CPNs through changing the heteroatom at key positions.