Intestinal Targeted Nanogel with Broad-Spectrum Autonomous ROS Scavenging Performance for Enhancing the Bioactivity of trans-Resveratrol.

Introduction: To improve the bioavailability of trans-resveratrol (trans-Res), it is commonly co-delivered with antioxidant bioactives using a complex synthetic intestinal targeted carrier, however, which makes practical application challenging. Methods: A nanogel (Ngel), as broad-spectrum autonomous ROS scavenger, was prepared using selenized thiolated sodium alginate (TSA-Se) and crosslinked with calcium lactate (CL) for loading trans-Res to obtain Ngel@Res, which maintained spherical morphology in the upper digestive tract but broke down in the lower digestive tract, resulting in trans-Res release. Results: Under protection of Ngel, trans-Res showed enhanced stability and broad-spectrum ROS scavenging activity. The synergistic mucoadhesion of Ngel prolonged the retention time of trans-Res in the intestine. Ngel and Ngel@Res increased the lifespan of Caenorhabditis elegans to 26.00 ± 2.17 and 26.00 ± 4.27 days by enhancing the activity of antioxidases, upregulating the expression of daf-16, sod-5 and skn-1, while downregulating the expression of daf-2 and age-1. Conclusion: This readily available, intestinal targeted selenized alginate-based nanogel effectively improves the bioactivity of trans-Res.

Controlled decoration of nanoceria on the surface of MoS2nanoflowers to improve the biodegradability and biocompatibility inDrosophila melanogastermodel.

In recent years, nanozymes based on two-dimensional (2D) nanomaterials have been receiving great interest for cancer photothermal therapy. 2D materials decorated with nanoparticles (NPs) on their surface are advantageous over conventional NPs and 2D material based systems because of their ability to synergistically improve the unique properties of both NPs and 2D materials. In this work, we report a nanozyme based on flower-like MoS2nanoflakes (NFs) by decorating their flower petals with NCeO2using polyethylenimine (PEI) as a linker molecule. A detailed investigation on toxicity, biocompatibility and degradation behavior of fabricated nanozymes in wild-typeDrosophila melanogastermodel revealed that there were no significant effects on the larval size, morphology, larval length, breadth and no time delay in changing larvae to the third instar stage at 7-10 d for MoS2NFs before and after NCeO2decoration. The muscle contraction and locomotion behavior of third instar larvae exhibited high distance coverage for NCeO2decorated MoS2NFs when compared to bare MoS2NFs and control groups. Notably, the MoS2and NCeO2-PEI-MoS2NFs treated groups at 100µg ml-1covered a distance of 38.2 mm (19.4% increase when compared with control) and 49.88 mm (no change when compared with control), respectively. High-resolution transmission electron microscopy investigations on the new born fly gut showed that the NCeO2decoration improved the degradation rate of MoS2NFs. Hence, nanozymes reported here have huge potential in various fields ranging from biosensing, cancer therapy and theranostics to tissue engineering and the treatment of Alzheimer's disease and retinal therapy.

Sequentially pH-Responsive Drug-Delivery Nanosystem for Tumor Immunogenic Cell Death and Cooperating with Immune Checkpoint Blockade for Efficient Cancer Chemoimmunotherapy.

Chemoimmunotherapy has anchored a new blueprint for cancer management. As a burgeoning approach, immunotherapy has shifted the paradigm of traditional chemotherapy and opened up new prospects for cancer treatment. Here, a sequentially pH-responsive doxorubicin (DOX) delivery nanosystem is designed for simultaneous chemotherapy and tumor immunogenic cell death (ICD). DOX is modified into pH-sensitive cis-aconityl-doxorubicin (CAD) for being easily adsorbed by polycationic polyethylenimine (PEI), and the PEI/CAD complexes are in situ-shielded by aldehyde-modified polyethylene glycol (PEG). The PEG/PEI/CAD nanoparticles (NPs) can keep stable in neutral physiological pH during systemic circulation but will detach PEG shielding once in slightly acidic tumor extracellular pH. The exposed positive PEI/CAD complexes are endocytosed effortlessly, and CAD is then converted back to DOX by endosomal-acidity-triggered cis-aconityl cleavage. The released DOX further elicits ICD, and the moribund tumor cells will release antigens and damage-associated molecular patterns to recruit dendritic cells and activate antitumor immunity. An excellent therapeutic effect is achieved when the immune checkpoint PD-1 antibody (aPD-1) is utilized to cooperate with the PEG/PEI/CAD NPs for blocking tumor immune escape and maintaining antitumor activity of the ICD-instigated T cells. The sequentially pH-responsive DOX delivery nanosystem cooperating with immune checkpoint blockade will provide a potential strategy for cancer chemoimmunotherapy.

99mTc radiolabeling of polyethylenimine capped carbon dots for tumor targeting: synthesis, characterization and biodistribution.

PURPOSE: Due to the favorable physicochemical properties and the biocompatibility, carbon dots (CDs) have gained a great attention as a tumor targeting agent. This study investigates polyethylenimine capped CDs (PEI capped CDs) as a prospective nanocarrier of technetium-99m (99mTc) for tumor targeting. Technetium-labeled CDs could be introduced as a promising candidate for single photon emission tomography (SPECT) imaging. MATERIALS AND METHODS: Polyethylenimine capped CDs were prepared by hydrothermal method using hyperbranched PEI and citric acid. For a purpose of comparison, citrate capped CDs were also prepared by microwave irradiation. Both types of CDs were characterized and radiolabeled with 99mTc using sodium borohydride (NaBH4) as a reducing agent. Biodistribution and tumor targeting efficiency of the produced radiolabeled CDs have been studied in Earlich ascites tumor mice model. RESULTS: Citrate capped CDs and PEI capped CDs have been synthesized successfully and characterized. High radiochemical yield of 99mTc-citrate capped CDs 99mTc-PEI capped CDs was obtained (97 ± 0.7 and 90 ± 0.2, respectively). Biodistribution studies of 99mTc-labeled PEI capped CDs have shown a potential tumor uptake (10 ± 0.5% Radioactivity/gram tumor) with high target to non-target ratio (T/NT) around 7 at 1-h post injection. 99mTc-citrate capped CDs have achieved a lower tumor uptake level (3.8 ± 0.3% Radioactivity/gram tumor 1 h post injection). CONCLUSION: This study introduces PEI capped CDs as a promising nanocarrier of 99mTc for efficient tumor targeting. Technetium-labeled PEI capped CDs could be utilized as a potential SPECT tumor imaging agent.

A Radiolabeled Self-assembled Nanoparticle Probe for Diagnosis of Lung-Metastatic Melanoma.

Melanoma is a highly malignant skin cancer that frequently metastasizes to the lung, bone, and brain at an early phase. Therefore, noninvasive detection of metastasized melanoma could be beneficial to determine suitable therapeutic strategies. We previously reported a biocompatible ternary anionic complex composed of plasmid DNA (pDNA), polyethyleneimine (PEI), and γ-polyglutamic acid (γ-PGA) based on an electrostatic interaction, which was highly taken up by melanoma cells (B16-F10), even if it was negatively charged. Here, we developed a radiolabeled γ-PGA complex by using indium-111 (111In)-labeled polyamidoamine dendrimer (4th generation; G4) instead of pDNA and iodine-125 (125I)-labeled PEI instead of native PEI, and evaluated its effectiveness as a melanoma-targeted imaging probe. This ternary complex was synthesized at a theoretical charge ratio; carboxyl groups of 111In-diethylenetriaminepentaacetic acid (DTPA)-G4 : amino groups of 125I-PEI : carboxyl groups of γ-PGA was 1 : 8 : 16, and the size and zeta potential were approximately 29 nm and -33 mV, respectively. This complex was taken up by B16-F10 cells with time. Furthermore, a biodistribution study, using normal mice, demonstrated its accumulation in the liver, spleen, and lung, where macrophage cells are abundant. Almost the same level of radioactivity derived from both 111In and 125I was observed in these organs at an early phase after probe injection. Compared with the normal mice, significantly higher lung-to-blood ratios of radioactivity were observed in the B16-F10-lung metastatic cancer model. In conclusion, the radiolabeled γ-PGA complex would hold potentialities for nuclear medical imaging of lung metastatic melanoma.

A transport system based on a quantum dot-modified nanotracer is genetically and developmentally stable in pregnant mice.

The use of nanoscale materials (NMs) could cause problems such as cytotoxicity, genomic aberration, and effects on human health, but the impacts of NM exposure during pregnancy remain uncharacterized in the context of clinical applications. It was sought to determine whether nanomaterials pass through the maternal-fetal junction at any stage of pregnancy. Quantum dots (QDs) coated with heparinized Pluronic 127 nanogels and polyethyleneimine (PEI) were administered to pregnant mice. The biodistribution of QDs, as well as their biological impacts on maternal and fetal health, was evaluated. Encapsulation of QDs with a nanogel coating produces a petal-like nanotracer (PNt), which could serve as a nano-carrier of genes or drugs. PNts were injected through the tail vein and accumulated in the liver, kidneys, and lungs. QD accumulation in reproductive organs (uterus, placenta, and fetus) differed among phases of pregnancy. In phase I (7 days of pregnancy), the QDs did not accumulate in the placenta or fetus, but by phase III (19 days) they had accumulated at high levels in both tissues. Karyotype analysis revealed that the PNt-treated pups did not have genetic abnormalities when dams were treated at any phase of pregnancy. PNts have the potential to serve as carriers of therapeutic agents for the treatment of the mother or fetus and these results have a significant impact on the development and application of QD-based NPs in pregnancy.

COMPARATIVE RENAL DISPOSITION OF CREATINE, AND TECHNETIUM DIAGNOSTIC CONTRAST AGENTS IN THE PIGEON (COLUMBA LIVIA).

Clinical assessment of renal function in avian species often involves the measurement of plasma uric acid and blood urea nitrogen, relatively insensitive markers of renal dysfunction and dehydration. In mammals, endogenous creatinine is widely used as an indicator of renal glomerular dysfunction. However, avian species produce primarily creatine. Here, renal creatine, 99mTc99-DTPA (diethylenepentaacetic acid, DTPA) and 99mTc-MAG3 (mercaptoacetyl triglycine, MAG3) renal clearances are characterized in the pigeon avian model by infusing DTPA with inulin and creatine with each tracer and examining the slope of their blood disappearance curves. Clearance curves for inulin and DTPA were parallel, suggesting DTPA is cleared by renal filtration. MAG3 clearance (slope: -2.74 × 105, r2 = 0.97) had a slope almost 10-fold steeper than for DTPA (slope: -6.29 × 104, r2 = 0.90), and orders of magnitude steeper than for creatine (slope: -1.4, r2 = 1.0). These results suggest that DTPA is cleared by glomerular filtration like inulin, while MAG3 is filtered and actively excreted in a manner similar to mammals. In contrast, creatine is filtered and resorbed, has a larger volume of distribution (Vd), or exhibits a greater blood protein binding, making it more complex as a renal marker, when compared with creatinine handling in mammals. The two radiotracers can be readily adapted for use in birds, inviting both qualitative and semiquantitative functional evaluation of avian renal function for research and clinical purposes. The elimination of creatine appears to be more complex requiring further study.

AS1411 aptamer modified carbon dots via polyethylenimine-assisted strategy for efficient targeted cancer cell imaging.

OBJECTIVES: Carbon dots (CDs), as a fascinating class of fluorescent carbon nanomaterials, have been proven to be powerful tools in the field of bioimaging and biosensing due to their small size, suitable photostability and favourable biocompatibility. However, the cellular uptake of free CDs lacks selectivity and the same negative charges as cell membranes may cause inefficient cell internalization. In this study, an efficient detecting and targeting nanosystem was developed based on the DNA aptamer AS1411 modified CDs with polyethyleneimine (PEI) as connecting bridge. MATERIALS AND METHODS: Hydrothermally prepared CDs were assembled with positive-charged PEI, followed by conjugation with AS1411 through electrostatic interaction to form CDs-PEI-AS1411 nanocomplexes. The CDs, CDs-PEI and CDs-PEI-AS1411 were characterized by transmission electron microscopy (TEM), fourier transform infrared (FTIR) spectra, UV-vis spectra, zeta potential measurements and capillary electrophoresis characterizations. The cytotoxicity investigation of the CDs-PEI-AS1411 and CDs-PEI in both MCF-7 and L929 cells was carried out by the CCK-8 assay. The cellular uptake of the CDs-PEI-AS1411 was studied with confocal microscopy and flow cytometry. RESULTS: The as-prepared nanosystem possessed good photostability and no obvious cytotoxicity. On the basis of the confocal laser scanning microscope observation and the flow cytometry studies, the cellular uptake of CDs-PEI-AS1411 nanosystem in MCF-7 cells was significantly higher than that of L929 cells, which revealed the highly selective detection ability of nucleolin-positive cells. CONCLUSIONS: The results of this study indicated that the CDs-PEI-AS1411 nanosystem had a potential value in cancer cell targeted imaging.

Gradient Redox-Responsive and Two-Stage Rocket-Mimetic Drug Delivery System for Improved Tumor Accumulation and Safe Chemotherapy.

Recent drug delivery nanosystems for cancer treatment still suffer from the poor tumor accumulation and low therapeutic efficacy due to the complex in vivo biological barriers. To resolve these problems, in this work, a novel gradient redox-responsive and two-stage rocket-mimetic drug nanocarrier is designed and constructed for improved tumor accumulation and safe chemotherapy. The nanocarrier is constructed on the basis of the disulfide-doped organosilica-micellar hybrid nanoparticles and the following dual-functional modification with disulfide-bonded polyethylene glycol (PEG) and amido-bonded polyethylenimine (PEI). First, prolonged circulation duration in the bloodstream is guaranteed due to the shielding of the outer PEG chains. Once the nanocarrier accumulates at the tumoral extracellular microenvironment with low glutathione (GSH) concentrations, the first-stage redox-responsive behavior with the separation of PEG and the exposure of PEI is triggered, leading to the improved tumor accumulation and cellular internalization. Furthermore, with their endocytosis by tumor cells, a high concentration of GSH induces the second-stage redox-responsiveness with the degradation of silsesquioxane framework and the release of the encapsulated drugs. As a result, the rocket-mimetic drug carrier displays longer circulation duration in the bloodstream, higher tumor accumulation capability, and improved antitumor efficacy (which is 2.5 times higher than that with inseparable PEG). It is envisioned that the rocket-mimetic strategy can provide new solutions for improving tumor accumulation and safety of nanocarriers in further cancer chemotherapy.

Fluorination effect to intermediate molecular weight polyethylenimine for gene delivery systems.

Fluorinated intermediate molecular weight polyethylenimine (FP2ks) with various fluorination degrees was synthesized by conjugation with heptafluorobutyric anhydride and the fluorination effect for gene delivery systems was examined. FP2ks could condense pDNA, forming compact, positively charged, and nano-sized spherical particles. It was thought that their decreased electrostatic interaction with pDNA would be compensated by hydrophobic interaction. The cytotoxicity of FP2ks was increased with the increase of fluorination degree, probably due to the cellular membrane disruption via hydrophobic interaction with FP2ks. The transfection efficiency of highly fluorinated FP2ks was not severely affected in serum condition, assuming their good serum-compatibility. Discrepancy between their higher cellular uptake efficiency and lower transfection efficiency than PEI25k was thought to arise from the formation of compact polyplexes followed by the decreased dissociation of pDNA. It was also suggested that multiple energy-dependent cellular uptake mechanisms and endosome buffering would mediate the transfection of FP2ks.

Biodistribution/biostability assessment of siRNA after intravenous and intratracheal administration to mice, based on comprehensive analysis of in vivo/ex vivo/polyacrylamide gel electrophoresis fluorescence imaging.

We performed in vivo/ex vivo/polyacrylamide gel electrophoresis (PAGE) fluorescence imaging of near-infrared fluorescence (NIRF)-labeled siRNA (Cy5.5-siGL3) in mice to investigate the validity of each fluorescence imaging result as the biodistribution/biostability assessment of siRNA. Statistically significant correlations could be obtained between the in vivo and ex vivo fluorescence intensities of Cy5.5 in the relevant regions/tissues, except the lung region/tissue after intravenous administration. On PAGE fluorescence images with the naked formulation, there was no band corresponding to intact Cy5.5-siGL3 from all the tissues evaluated after intravenous administration, indicating that the fluorescence detected by in vivo and ex vivo fluorescence imaging was derived from degraded Cy5.5-siGL3 or free Cy5.5 cleaved from Cy5.5-siGL3. However, the band was detected from the lungs after intratracheal administration of the naked formulation, confirming higher stability of siRNA on the respiratory epithelium than in the blood. Regarding the polyethyleneimine formulation, the band was detected from all the tissues evaluated after intravenous administration and from the lungs after intratracheal administration, verifying the enhanced stability of siRNA in the body. These results clearly indicated the necessity of comprehensive analysis from in vivo/ex vivo/PAGE fluorescence imaging to precisely assess the distribution and stability of NIRF-labeled oligonucleotides including siRNA in the body.

Effects of carbon dots surface functionalities on cellular behaviors - Mechanistic exploration for opportunities in manipulating uptake and translocation.

Carbon dots (CDots) for their excellent optical and other properties have been widely pursued for potential biomedical applications, in which a more comprehensive understanding on the cellular behaviors and mechanisms of CDots is required. For such a purpose, two kinds of CDots with surface passivation by 3-ethoxypropylamine (EPA-CDots) and oligomeric polyethylenimine (PEI-CDots) were selected for evaluations on their uptakes by human cervical carcinoma HeLa cells at three cell cycle phases (G0/G1, S and G2/M), and on their different internalization pathways and translocations in cells. The results show that HeLa cells could internalize both CDots by different pathways, with an overall slightly higher internalization efficiency for PEI-CDots. The presence of serum in culture media could have major effects, significantly enhancing the cellular uptake of EPA-CDots, yet markedly inhibiting that of PEI-CDots. The HeLa cells at different cell cycle phases have different behaviors in taking up the CDots, which are also affected by the different dot surface moieties and serum in culture media. Mechanistic implications of the results and the opportunities associated with an improved understanding on the cellular behaviors of CDots for potentially the manipulation and control of their cellular uptakes and translocations are discussed.

Exhausting tumor associated macrophages with sialic acid-polyethyleneimine-cholesterol modified liposomal doxorubicin for enhancing sarcoma chemotherapy.

To overstep the dilemma of chemical drug degradation within powerful lysosomes of tumor associated macrophages (TAMs), a sialic acid-polyethylenimine-cholesterol (SA-PEI-CH) modified liposomal doxorubicin (DOX-SPCL) was designed with both TAMs targeting and smart lysosomal trafficking. The modified liposome DOX-SPCL performed particle size as 103.2 ±â€¯3.1 nm and zeta potential as -4.5 ±â€¯0.9 mV with encapsulation efficiency as 95.8 ±â€¯0.5%. In in vitro cell experiments, compared with conventional liposomal doxorubicin (DOX-CL) and PEGylated liposomal doxorubicin (DOX-PL), DOX-SPCL showed a selective binding on TAMs and a mere lysosomal concentration. In pharmacokinetic study, DOX-SPCL effectively impeded/delayed the disposition of mononuclear phagocyte system (MPS) with a value of AUC0-t as 796.03 ±â€¯66.93 mg L-1 h. In S180 sarcomas bearing mice, DOX-SPCL showed the greatest tumor inhibition rate (92.7% ±â€¯3.6%) compared with DOX-CL (46.4% ±â€¯2.0%) or DOX-PL (58.8% ±â€¯7.6%). The <0.5% positive region of TAMs in tumor section indicated a super TAMs exhaustion for DOX-SPCL treatment. Conclusively, DOX-SPCL was supposed as a safe and effective liposomal preparation for clinical sarcoma treatment via TAMs targeting/deletion delivery strategy.

Tunable Properties of Poly-DL-Lactide-Monomethoxypolyethylene Glycol Porous Microparticles for Sustained Release of Polyethylenimine-DNA Polyplexes.

Direct pulmonary delivery is a promising step in developing effective gene therapies for respiratory disease. Gene therapies can be used to treat the root cause of diseases, rather than just the symptoms. However, developing effective therapies that do not cause toxicity and that successfully reach the target site at therapeutic levels is challenging. We have developed a polymer-DNA complex utilizing polyethylene imine (PEI) and DNA, which was then encapsulated into poly(lactic acid)-co-monomethoxy poly(ethylene glycol) (PLA-mPEG) microparticles via double emulsion, solvent evaporation. Then, the resultant particle size, porosity, and encapsulation efficiency were measured as a function of altering preparation parameters. Microsphere formation was confirmed from scanning electron micrographs and the aerodynamic particle diameter was measured using an aerodynamic particle sizer. Several formulations produced particles with aerodynamic diameters in the 0-5 µm range despite having larger particle diameters which is indicative of porous particles. Furthermore, these aerodynamic diameters correspond to high deposition within the airways when inhaled and the measured DNA content indicated high encapsulation efficiency. Thus, this formulation provides promise for developing inhalable gene therapies.

Surface assembly of poly(I:C) on polyethyleneimine-modified gelatin nanoparticles as immunostimulatory carriers for mucosal antigen delivery.

The mucosal immune system is the host's first line of defense against invasion by foreign pathogens. Gelatin nanoparticles (GNPs) are suitable carriers for the delivery of antigens via various routes of administration. In the present study, GNPs were modified with polyethyleneimine (PEI), a positively charged polymer. Then, ovalbumin (OVA) and polyinosinic:polycytidylic acid (poly(I:C)), an immunostimulant, were adsorbed onto the surface of the positively charged GNPs. We assessed whether GNPs could act as an effective mucosal vaccine that is capable of inducing both mucosal and systemic immune responses. The results showed that GNPs effectively adsorbed OVA/poly(I:C), facilitated cellular uptake by RAW 264.7 macrophage cells and murine bone marrow-derived dendritic cells (BMDCs) in vitro, and led to increased expression of the maturation markers CD80 and CD86 on BMDCs. Furthermore, GNPs induced increased secretion of proinflammatory cytokines in both RAW 264.7 and BMDCs. C57BL/6 mice that were intranasally twice-immunized with OVA/poly(I:C)-loaded GNPs produced high levels of serum OVA-specific IgG antibodies and secretory IgA in nasal and lung lavage. Spleen cells from immunized mice were collected and re-stimulated with OVA, and results showed significantly augmented production of IFN-γ, IL-4, IL-5, and IL-6 in mice that received OVA/poly(I:C)-loaded GNPs. Moreover, intranasal immunization with OVA/poly(I:C)-loaded GNPs resulted in the inhibition of EG7 tumor growth in C57BL/6 mice. Taken together, these results indicate that nasal administration of OVA/poly(I:C)-loaded GNPs elicited effective mucosal and systemic immune responses, which might be useful for further applications of antigen delivery. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1228-1237, 2019.

Layer-by-layer assembled PEI-based vector with the upconversion luminescence marker for gene delivery.

The upconversion luminescence (UCL) marker based on upconversion nanoparticles (UCNPs) shows unique advantages over traditional fluorescence markers, such as enhanced tissue penetration, better photostability, and less autofluorescence. Herein, we constructed a new UCL gene-delivery nonviral vector via layer-by-layer self-assembly of poly(ethylene imine) (PEI) with UCNPs. To reduce the cytotoxicity of PEI, citric acid (CA) was introduced for aqueous modification, and PEI assembly was introduced on the UCNP surface. Our data show that the nonviral vector for UCL gene-delivery demonstrates excellent photostability, low toxicity, and good stability under physiological or serum conditions and can strongly bind to DNA. Moreover, this UCL PEI-based vector could serve as a promising fluorescent gene-delivery carrier for theranostic applications.

Polyethyleneimine-Coated Manganese Oxide Nanoparticles for Targeted Tumor PET/MR Imaging.

A Mn3O4 nanoparticle (NP)-based dual-modality probe has been developed for tumor positron emission tomography (PET)/magnetic resonance (MR) imaging. The dual-modality imaging probe was constructed by modifying multifunctional polyethyleneimine (PEI)-coated Mn3O4 NPs with folic acid (FA), followed with the radiolabeling with 64Cu. The formed imaging probe was utilized for PET/MR imaging of human cervical cancer mouse xenografts, which overexpress folate receptor (FR). The PEI-coated Mn3O4 NPs were synthesized using a solvothermal approach via decomposition of acetylacetone manganese. Multifunctional groups, including fluorescein isothiocyanate (FI), PEGylated FA, and NOTA chelator, were then sequentially loaded onto the surface of the amine groups of the Mn3O4 NPs. The remaining PEI amines were neutralized by the acetylation reaction. The resulting NOTA-FA-FI-PEG-PEI-Ac-Mn3O4 NPs were fully characterized and evaluated in vitro and successfully radiolabeled with 64Cu for tumor PET/MR imaging in small animals. In vivo blocking experiments were performed to determine the FR binding specificity of NPs. PET imaging results demonstrated that 64Cu-labeled Mn3O4 NPs display good tracer uptake in the FR-expressing HeLa tumors (tumor-to-muscle (T/M) ratio: 5.35 ± 0.31 at 18 h postinjection (pi)) and substantially reduced tracer uptake in the FR-blocked HeLa tumors (T/M ratio: 2.78 ± 0.68 at 18 h pi). The ex vivo data, including PET imaging and biodistribution, further confirmed the tumor binding specificity of the 64Cu-labeled Mn3O4 NPs. Moreover, the FR-targeted Mn3O4 NPs exhibited efficient T1-weighted MR imaging (MRI), leading to the precise tumor MRI at 18 h pi. PET/MR imaging with the 64Cu-NOTA-FA-FI-PEG-PEI-Ac-Mn3O4 NPs may offer a new quantitative approach to precisely measure the FR in tumors. The strategy of incorporating PEI nanotechnology into the construction of new biomaterials may be applied for the construction of novel nanoplatforms for cancer diagnosis and therapy.

Ultrafast synthesis of ultrasmall polyethylenimine-protected AgBiS2 nanodots by "rookie method" for in vivo dual-modal CT/PA imaging and simultaneous photothermal therapy.

Developing a biocompatible nanotheranostic platform integrating diagnostic and therapeutic functions is a great prospect for cancer treatment. However, it is still a great challenge to synthesize nanotheranostic agents using an ultra-facile method. In the research reported here, ultrasmall polyethylenimine-protected silver bismuth sulfide (PEI-AgBiS2) nanodots were successfully synthesized using an ultra-facile and environmentally friendly strategy (1 min only at room temperature), which could be described as a "rookie method". PEI-AgBiS2 nanodots show good monodispersity and biocompatibility. For the first time, PEI-AgBiS2 nanodots were reported as a powerful and safe nanotheranostic agent for cancer treatment. PEI-AgBiS2 nanodots exhibit excellent computed tomography (CT) and photoacoustic (PA) dual-modal imaging ability, which could effectively guide photothermal cancer therapy. Furthermore, PEI-AgBiS2 nanodots exhibit a high photothermal conversion efficiency (η = 35.2%). The photothermal therapy (PTT) results demonstrated a highly efficient tumor ablation ability. More importantly, the blood biochemistry and histology analyses verify that the PEI-AgBiS2 nanodots have negligible long-term toxicity. This work highlights that PEI-AgBiS2 nanodots produced using this extremely effective method are a high-performance and safe PTT agent. These findings open a new gateway for synthesizing nanotheranostic agents by using this ultra-facile method in the future.

Reactive Self-Assembly and Specific Cellular Delivery of NCO-sP(EO-stat-PO)-Derived Nanogels.

This study presents the reactive self-assembly of isocyanate functional and amphiphilic six-arm, star-shaped polyether prepolymers in water into nanogels. Intrinsic molecular amphiphilicity, mainly driven by the isophorone moiety at the distal endings of the star-shaped molecules, allows for the preparation of spherical particles with an adjustable size of 100-200 nm by self-assembly and subsequent covalent cross-linking without the need for organic solvents or surfactants. Covalent attachment of a fluorescence dye and either the cell-penetrating TAT peptide or a random control peptide sequence shows that only TAT-labeled nanogels are internalized by HeLa cells. The nanogels thus specifically enter the cells and accumulate in the perinuclear area in a time- and concentration-dependent manner.

Investigation on vascular cytotoxicity and extravascular transport of cationic polymer nanoparticles using perfusable 3D microvessel model.

Vascular networks are the first sites exposed to cationic polymer nanoparticles (NPs) administered intravenously, and thus function as a barrier for NPs reaching the target organ. While cationic polymer NPs have been intensively studied as non-viral delivery systems, their biological effects in human microvessels have been poorly investigated due to a lack of appropriate in vitro systems. Here, we employed a three-dimensional microvessel on a chip, which accurately models in vivo conditions. An open and perfused microvessel surrounded by pericytes was shown to reproduce the important features of living vasculature, including barrier function and biomarkers. Using this microvessel chip, we observed contraction of the microvascular lumen induced by perfused polyethylenimine (PEI)/DNA NPs. We demonstrated that the oxidative stress present when microvessels were exposed to PEI NPs led to rearrangement of microtubules resulting in microvessel contraction. Furthermore, the transcytotic behavior of PEI NPs was analyzed in the microvessel by monitoring the escape of PEI NPs from the microvascular lumen into the perivascular region, which was not possible in two-dimensional culture systems. With our new understanding of the different behaviors of cationic polymer NPs depending on their transcytotic route, we suggest that caveolae-mediated transcytosis is a powerful route for efficient extravascular transport. STATEMENT OF SIGNIFICANCE: Microvascular networks are not only biological system constituting largest surface area in the body and but also first site exposed to nanoparticle in vivo. While cationic polymer NPs have been intensively studied as non-viral delivery systems, its biological effects in human microvessel have been poorly investigated due to lack of appropriate in vitro systems. Here, we microengineered an open and perfused 3D pericyte incorporated microvessel model which possesses same morphological characteristic of in vivo. Using the microengineered model, this study represents the first report of transcytotic behavior of NPs in 3D microvessel, and its effect on extravasation efficiency. Our study lays the groundwork for the integration of innovative technologies to examine blood vessel-nanoparticle interaction, which a critical but ill-defined phenomenon.