Jinjoo Kim

Effects of gold nanoparticle-based vaccine size on lymph node delivery and cytotoxic T-lymphocyte responses

Abstract Although it has been shown that the size of nanoparticle‐based vaccines is a key determining factor for the induction of immune responses, few studies have provided detailed analyses of thresholds or critical sizes of nanoparticle vaccines. Here we report effects of the size of gold nanoparticle (GNP)‐based vaccines on their efficiency of delivery to lymph nodes (LNs) and induction of CD8+ T‐cell responses. We further propose a threshold size of GNPs for use as an effective vaccine. To examine the effects of GNP size, we synthesized GNPs with diameters of 7, 14 and 28 nm, and then conjugated them with recombinant ovalbumin (OVA) as a model antigen. The resulting OVA‐GNPs had hydrodynamic diameter (HD) of ˜ 10, 22, and 33 nm for 7, 14 and 28 nm GNPs, respectively and exhibited a size‐dependent increase in cellular uptake by dendritic cells (DCs) and subsequent T‐cell cross‐priming and activation. Upon injection into a mouse footpad, both 22‐ and 33‐nm OVA‐GNPs showed much higher delivery efficiency to draining LNs than did 10‐nm OVA‐GNPs. An ex vivo restimulation assay using OVA as an antigen revealed that frequencies of OVA‐specific CD8+ T cells were higher in mice immunized with 22‐ and 33‐nm OVA‐GNPs than in those immunized with 10‐nm OVA‐GNPs; moreover, these cells were shown to be poly‐functional. In a tumor‐prevention study, 22‐nm OVA‐GNPs showed greater antitumor efficacy, and higher infiltration of CD8+ T‐cells and greater tumor cell apoptosis and cell death than 10‐nm OVA‐GNPs. Taken together, our results suggest that the size threshold for induction of potent cellular responses and T‐cell poly‐functionality by GNPs lies between 10 nm and 22 nm, and highlight the importance of nanoparticle size as a critical parameter in designing and developing nanoparticle‐based vaccines. Graphical abstract Figure. No Caption available.

Photo-decomposable Organic Nanoparticles for Combined Tumor Optical Imaging and Multiple Phototherapies

Combination of photodynamic therapy (PDT) with photothermal therapy (PTT) has achieved significantly improved therapeutic efficacy compared to a single phototherapy modality. However, most nanomaterials used for combined PDT/PTT are made of non-biodegradable materials (e.g., gold nanorods, carbon nanotubes, and graphenes) and may remain intact in the body for long time, raising concerns over their potential long-term toxicity. Here we report a new combined PDT/PTT nanomedicine, designated SP3NPs, that exhibit photo-decomposable, photodynamic and photothermal properties. SP3NPs were prepared by self-assembly of PEGylated cypate, comprising FDA-approved PEG and an ICG derivative. We confirmed the ability of SP3NPs to generate both singlet oxygen for a photodynamic effect and heat for photothermal therapy in response to NIR laser irradiation in vitro. Also, the unique ability of SP3NPs to undergo irreversible decomposition upon NIR laser irradiation was demonstrated. Further our experimental results demonstrated that SP3NPs strongly accumulated in tumor tissue owing to their highly PEGylated surface and relatively small size (~60 nm), offering subsequent imaging-guided combined PDT/PTT treatment that resulted in tumor eradication and prolonged survival of mice. Taken together, our SP3NPs described here may represent a novel and facile approach for next-generation theranostics with great promise for translation into clinical practice in the future.

Bioengineered yeast-derived vacuoles with enhanced tissue-penetrating ability for targeted cancer therapy

Significance Tumor tissues have formidable physiological barriers, such as a high interstitial pressure and a densely entangled ECM. Most synthetic nanomaterials used for drug delivery fail to penetrate tumor tissues deeply and localize only in perivascular areas, thereby limiting their therapeutic efficacy. This report describes bioengineered yeast-derived natural nanocarriers for cancer-specific targeting and drug delivery. Budding yeast was genetically engineered to produce large numbers of nanosized compartments—vacuoles that display cancer—targeting ligands on their surface. The nanosized vacuoles significantly enhanced drug penetration in tumor xenografts, and consequently prevented tumor growth without eliciting immune responses. This result shows that the biological nanocarriers overcome the limitations associated with synthetic cancer-targeting nanomaterials, and thus can be used to treat various cancers. Despite the appreciable success of synthetic nanomaterials for targeted cancer therapy in preclinical studies, technical challenges involving their large-scale, cost-effective production and intrinsic toxicity associated with the materials, as well as their inability to penetrate tumor tissues deeply, limit their clinical translation. Here, we describe biologically derived nanocarriers developed from a bioengineered yeast strain that may overcome such impediments. The budding yeast Saccharomyces cerevisiae was genetically engineered to produce nanosized vacuoles displaying human epidermal growth factor receptor 2 (HER2)-specific affibody for active targeting. These nanosized vacuoles efficiently loaded the anticancer drug doxorubicin (Dox) and were effectively endocytosed by cultured cancer cells. Their cancer-targeting ability, along with their unique endomembrane compositions, significantly enhanced drug penetration in multicellular cultures and improved drug distribution in a tumor xenograft. Furthermore, Dox-loaded vacuoles successfully prevented tumor growth without eliciting any prolonged immune responses. The current study provides a platform technology for generating cancer-specific, tissue-penetrating, safe, and scalable biological nanoparticles for targeted cancer therapy.

Substituent Effects in BODIPY in Live Cell Imaging

Small-molecule organoselenium-based fluorescent probes possess great capacity in understanding biological processes through the detection of various analytes such as reactive oxygen/nitrogen species (ROS/RNS), biothiols (cysteine, homocysteine and glutathione), lipid droplets, etc. Herein, we present how substituents on the BODIPY system play a significant part in the detection of biologically important analytes for in vitro conditions and live cell imaging studies. The fluorescence of the probe was quenched by 2-chloro and 6-phenyl selenium groups; the probe shows high selectivity with NaOCl among other ROS/RNS, and gives a turn-on response. The maximum fluorescence intensity is attained within ≈1-2 min with a low detection limit (19.6 nm), and shows a ≈110-fold fluorescence enhancement compared to signals generated for other ROS/RNS. Surprisingly, in live cell experiments, the probe specifically located and accumulated in lipid droplets, and showed a fluorescence turn-on response. We believe this turn-on response occurred because of aggregation-induced emission (AIE), which surprisingly occurred only by introducing one lipophilic mesityl group at the meso position of the BODIPY.

Preparation and therapeutic evaluation of paclitaxel-conjugated low-molecular-weight chitosan nanoparticles

Synthetic and natural polymers have been widely utilized as raw materials for manufacturing drug-delivery vehicles to treat diseases. This widespread use reflects several favorable features of these polymers, including facile chemical modification, ease of creating nano-sized particles through a self-assembly process, the ability to solubilize or encapsulate hydrophobic drugs within the core, and enhanced accumulation in tumors by the so-called enhance permeability and retention (EPR) effect. Among such polymeric materials, natural polymers such as dextran, chitosan, and hyaluronic acid may have advantages over synthetic polymers in the preparation of nanoparticle (NP)-based drug delivery systems in terms of biocompatibility. Because such natural polysaccharide components are water-soluble, their polymers require modification with hydrophobic components before NP formation via a self-assembly process. It has been shown that hydrophobically modified dextran, hyaluronic acid, and high-molecular-weight chitosan self-assemble into NPs that exhibit effective anticancer efficacy through EPR effectmediated, passive tumor targeting. In fact, chitosan has been widely used in the pharmaceutical field because it is known to be biocompatible and biodegradable, and increases the solubility of hydrophobic drugs. Very recently, we utilized water-soluble, low-molecular-weight chitosan (LMWC) as a carrier to achieve oral delivery of anticancer drugs, such as paclitaxel (PTX) and docetaxel, and anti-diabetic peptide drugs, such as insulin and exendin-4. All conjugates between LMWC and drugs of interest in our previous studies showed high oral bioavailability with little toxicity, suggesting the potential of LMWC as a biocompatible carrier for drug-delivery applications. In the present study, we prepared conjugates between LMWC and PTX with different drug content and evaluated the therapeutic efficacy of self-assembled NPs formed from these conjugates (Figure 1(a)).

Gold Nanorod-based Photo-PCR System for One-Step, Rapid Detection of Bacteria

The polymerase chain reaction (PCR) has been an essential tool for diagnosis of infectious diseases, but conventional PCR still has some limitations with respect to applications to point-of-care (POC) diagnostic systems that require rapid detection and miniaturization. Here we report a light-based PCR method, termed as photo-PCR, which enables rapid detection of bacteria in a single step. In the photo-PCR system, poly(enthylene glycol)-modified gold nanorods (PEG-GNRs), used as a heat generator, are added into the PCR mixture, which is subsequently periodically irradiated with a 808-nm laser to create thermal cycling. Photo-PCR was able to significantly reduce overall thermal cycling time by integrating bacterial cell lysis and DNA amplification into a single step. Furthermore, when combined with KAPA2G fast polymerase and cooling system, the entire process of bacterial genomic DNA extraction and amplification was further shortened, highlighting the potential of photo-PCR for use in a portable, POC diagnostic system.

Prevention of Bacterial Colonization on Catheters by a One-Step Coating Process Involving an Antibiofouling Polymer in Water

As reports of multidrug resistant pathogens have increased, patients with implanted medical catheters increasingly need alternative solutions to antibiotic treatments. As most catheter-related infections are directly associated with biofilm formation on the catheter surface, which, once formed, is difficult to eliminate, a promising approach to biofilm prevention involves inhibiting the initial adhesion of bacteria to the surface. In this study, we report an amphiphilic, antifouling polymer, poly(DMA-mPEGMA-AA) that can facilely coat the surfaces of commercially available catheter materials in water and prevent bacterial adhesion to and subsequent colonization of the surface, giving rise to an antibiofilm surface. The antifouling coating layer was formed simply by dipping a model substrate (polystyrene, PET, PDMS, or silicon-based urinary catheter) in water containing poly(DMA-mPEGMA-AA), followed by characterization by X-ray photoelectron spectroscopy (XPS). The antibacterial adhesion properties of the polymer-coated surface were assessed for Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) growth under static (incubation in the presence of a bacterial suspension) and dynamic (bacteria suspended in a solution under flow) conditions. Regardless of the conditions, the polymer-coated surface displayed significantly reduced attachment of the bacteria (antiadhesion effect > ∼8-fold) compared to the bare noncoated substrates. Treatment of the implanted catheters with S. aureus in vivo further confirmed that the polymer-coated silicon urinary catheters could significantly reduce bacterial adhesion and biofilm formation in a bacterial infection animal model. Furthermore, the polymer-coated catheters did not induce hemolysis and were resistant to the adhesion of blood-circulating cells, indicative of high biocompatibility. Collectively, the present amphiphilic antifouling polymer is potentially useful as a coating platform that renders existing medical devices resistant to biofilm formation.

Nanoparticle-Assisted Transcutaneous Delivery of a Signal Transducer and Activator of Transcription 3-Inhibiting Peptide Ameliorates Psoriasis-like Skin Inflammation

Signal transducer and activator of transcription 3 (STAT3) is constitutively activated in psoriatic skin inflammation and acts as a key player in the pathogenesis and progression of this autoimmune disease. Although numerous inhibitors that intervene in STAT3-associated pathways have been tested, an effective, highly specific inhibitor of STAT3 has yet to be identified. Here, we evaluated the in vitro and in vivo biological activity and therapeutic efficacy of a high-affinity peptide specific for STAT3 (APTstat3) after topical treatment via intradermal and transcutaneous delivery. Using a preclinical model of psoriasis, we show that intradermal injection of APTstat3 tagged with a 9-arginine cell-penetrating peptide (APTstat3-9R) reduced disease progression and modulated psoriasis-related cytokine signaling through inhibition of STAT3 phosphorylation. Furthermore, by complexing APTstat3-9R with specific lipid formulations led to formation of discoidal lipid nanoparticles (DLNPs), we were able to achieve efficient skin penetration of the STAT3-inhibiting peptide after transcutaneous administration, thereby effectively inhibiting psoriatic skin inflammation. Collectively, these findings suggest that DLNP-assisted transcutaneous delivery of a STAT3-inhibiting peptide could be a promising strategy for treating psoriatic skin inflammation without causing adverse systemic events. Moreover, the DLNP system could be used for transdermal delivery of other therapeutic peptides.