The combination of nanotechnology and chemotherapy has resulted in more effective drug design via the development of nanomaterial-based drug delivery systems (DDSs) for tumor targeting. Stimulus-responsive DDSs in response to internal or external signals can offer precisely controlled delivery of preloaded therapeutics. Among the various DDSs, the photo-triggered system improves the efficacy and safety of treatment through spatiotemporal manipulation of light. Additionally, pH-induced delivery is one of the most widely studied strategies for targeting the acidic micro-environment of solid tumors. Accordingly, in this review, we discuss representative strategies for designing DDSs using light as an exogenous signal or pH as an endogenous trigger.

The use of photo-based nanomedicine in imaging and therapy has grown rapidly. The property of light in converting its energy into different forms has been exploited in the fields of optical imaging (OI) and phototherapy (PT) for diagnostic and therapeutic applications. The development of nanotechnology offers numerous advantages to overcome the challenges of OI and PT. Accordingly, in this review, we shed light on common photosensitive agents (PSAs) used in OI and PT; these include fluorescent and bioluminescent PSAs for OI or PT agents for photodynamic therapy (PDT) and photothermal therapy (PTT). We also describe photo-based nanotechnology systems that can be used in photo-based diagnostics and therapies by using various polymeric systems.

Purpose An AE147 peptide-conjugated nanocarrier based on PEGylated liposomes was developed in order to target the metastatic tumors overexpressing urokinase-type plasminogen activator receptor (uPAR), which cancer progression via uPA signaling. Therefore, the AE147 peptide-conjugated nanocarrier system may hold the potential for active targeting of metastatic tumors. Methods The AE147 peptide, an antagonist of uPAR, was conjugated to the PEGylated liposomes for targeting metastatic tumors overexpressing uPAR. Docetaxel (DTX), an anticancer drug, was incorporated into the nanocarriers. The structure of the AE147-conjugated nanocarrier, its physicochemical properties, and in vivo biodistribution were evaluated. Results The DTX-loaded nanocarrier showed a spherical structure, a high drug-loading capacity, and a high colloidal stability. Drug carrying AE147 conjugates were actively taken up by the uPAR-overexpressing MDA-MB-231 cancer cells. In vivo animal imaging confirmed that the AE147-conjugated nanoparticles effectively accumulated at the sites of tumor metastasis. Conclusion The AE147-nanocarrier showed potential for targeting metastatic tumor cells overexpressing uPAR and as a nanomedicine platform for theragnosis applications. These results suggest that this novel nano-platform will facilitate further advancements in cancer therapy.

Lutein has been used as a dietary supplement for the treatment of eye diseases, especially age-related macular degeneration. For oral formulations, we investigated lutein stability in artificial set-ups mimicking different physiological conditions and found that lutein was degraded over time under acidic conditions. To enhance the stability of lutein upon oral intake, we developed enteric-coated lutein solid dispersions (SD) by applying a polymer, hydroxypropyl methylcellulose acetate succinate (HPMCAS-LF), through a solventcontrolled precipitation method. The SD were characterized in crystallinity, morphology, and drug entrapment. In the dissolution profile of lutein SD, a F80 formulation showed resistance toward the acidic environment under simulated gastric conditions while exhibiting a bursting drug release under simulated intestinal conditions. Our results highlight the potential use of HPMCAS-LF as an effective matrix to enhance lutein bioavailability during oral delivery and to provide novel insights into the eye-care supplement industry, with direct benefits for the health of patients.

Introduction Ligand-conjugated liposomes are promising for the treatment of specific receptor-overexpressing cancers. However, previous studies have shown inconsistent results because of the varying properties of the ligand, presence of a polyethylene glycol (PEG) coating on the liposome, length of the linker, and density of the ligand. Methods Here, we prepared PEGylated liposomes using PEG-linkers of various lengths conjugated with folate and evaluated the effect of the PEG-linker length on the nanoparticle distribution and pharmacological efficacy of the encapsulated drug both in vitro and in vivo. Results When folate was conjugated to the liposome surface, the cellular uptake efficiency in folate receptor overexpressed KB cells dramatically increased compared to that of the normal liposome. However, when comparing the effect of the PEG-linker length in vitro, no significant difference between the formulations was observed. In contrast, the level of tumor accumulation of particles in vivo significantly increased when the length of the PEG-linker was increased. The tumor size was reduced by >40% in the Dox/FL-10K-treated group compared to that in the Dox/FL-2K- or 5K-treated groups. Discussion Our study suggests that as the length of PEG-linker increases, the tumor-targeting ability can be enhanced under in vivo conditions, which can lead to an increase in the antitumor activity of the encapsulated drug.