Passive Accumulation Research Articles

Indocyanine green–guided nephron-sparing surgery for pediatric renal tumors

BackgroundIndocyanine green (ICG), a water-soluble tricarbocyanine fluorophore, is being increasingly used for tumor localization based on its passive intra-tumoral accumulation due to enhanced permeability and retention in tumor tissue. Therefore, we hypothesized that ICG can provide contrast to facilitate accurate, real-time recognition of renal tumors at the time of nephron-sparing surgery in children. MethodsThis retrospective study examined the feasibility of ICG in guiding nephron-sparing surgery for pediatric renal tumors. ResultsWe reviewed the medical records of 8 pediatric patients with renal tumors in 12 kidneys. Intraoperative localization of tumor with near infrared guidance was successful in all 12 kidneys. However, we consistently found an inverse pattern of near infrared signal in which the normal kidney demonstrated increased fluorescent signal relative to the kidney tumor. ConclusionsFluorescence-guided renal tumor delineation is unique because it has an inverse pattern of near infrared signal in which the normal kidney demonstrates increased signal relative to the adjacent tumor. Nevertheless fluorescence-guided distinguishing of renal tumor from surrounding normal kidney is feasible.

Self‐Delivered Supramolecular Nanomedicine with Transformable Shape for Ferrocene‐Amplified Photodynamic Therapy of Breast Cancer and Bone Metastases

AbstractAlthough nanomedicines can passively target tumor through the enhanced permeability and retention (EPR) effect, their distribution and retention are limited by complex tumor microenvironment. Herein, a self‐delivery supramolecular nanoplatform with shape‐transforming capacity (Ce6‐CD/Fc‐pep‐PEG) is constructed by the host‐guest interaction between chlorin e6‐ conjugated β‐cyclodextrin (Ce6‐CD) and ferrocene‐modified FFVLG3C‐PEG conjugates (Fc‐pep‐PEG). Following passive accumulation mediated by the EPR effect, hydrophobic Fc is oxidized to water‐soluble Fc+ by endogenous ROS in tumor sites. The resulting Fc+‐pep‐PEG fragment dissociated from Ce6‐CD and recombined to nanofibers through the intermolecular hydrogen bonds among FFVLG3C peptide chains, thus enhancing the retention. Meanwhile, the Ce6‐CD fragment still maintained the form of spherical micelles with a relatively smaller size to penetrate into the deep tumor regions. Moreover, the cascade Fenton reaction catalyzed by Fc generated •OH and O2 to relieve hypoxia and amplify PDT efficiency. In turn, ROS generated by PDT promoted shape‐transformation and continuous occurrence of Fenton reaction. In vitro and in vivo evaluations verify that through the positive feedback loop, Ce6‐CD/Fc‐pep‐PEG can induce a potent antitumor immune response and achieve ROS‐potentiated elimination of primary tumor and bone metastasis.

Development of an Antibody-Targeted Nanoparticle for Early Detection of Minimal Residual Disease in Multiple Myeloma

Development of methods for the early detection of minimal residual disease (MRD) is a central challenge to the effective treatment of patients with multiple myeloma (MM). The presence of MRD is directly linked to both the durations of treatment response as well as to long-term survival outcomes. Current diagnostic methods utilize serologic biomarkers and/or repeated bone marrow samplings that do not take into account the spatial heterogeneity of the tumor microenvironment; as such, they often lead to false negative results. Available diagnostic imaging agents are not designed to detect plasma-cell populations; they rely on passive tumor accumulation that hinders both their detection specificity and sensitivity.Here, we utilize ultra-small gadolinium-based nanoparticles (Gd-NPs) that are conjugated to monoclonal antibodies to enable magnetic resonance imaging of plasma cells in a murine model of MM. We demonstrate the first example of utilizing a non-invasive imaging agent to improve early detection of MRD after therapeutic administration.To develop a plasma-cell targeted MRI contrast agent that would improve early detection of MRD, we fabricated ultra-small, sub-5 nm Gd-NPs that were conjugated to monoclonal antibodies directed against different receptors on the surfaces of MM cells. We postulated that these ultra-small Gd-NPs would minimally affect antibody targeting upon conjugation and could achieve improved in vivo imaging of plasma cell populations. For targeting of MM cells, we selected antibodies against the signaling lymphocytic activation molecule-F7 (SLAMF7) and the B-cell maturation antigen (BCMA). Both antigens are almost exclusively present on the surfaces of malignant B-cells. To generate our MM-targeted imaging construct, the surfaces of our Gd-NPs were decorated with free N-hydroxysuccinimide (NHS) groups and were conjugated to NHS groups on the surface of anti-SLAMF7 and BCMA antibodies via a bissulfosuccinimidyl suberate crosslinker.An MRI study was undertaken to compare the efficiencies of the various nanoparticle constructs (Gd-NP, NP-SLAMF7, and NP-BCMA) to identify identical plasma cell burdens and as compared to the FDA-approved contrast agent MagnevistTM. Gd uptake in the spine and femurs of animals were visualized using a 7T MRI machine with a T1-GRE sequence. The specificity of each of the administered contrast agents to target MM cells was confirmed by animal sacrifice immediately after MRI; the femurs and vertebral tissues of each animal were harvested for histologic assessment after staining by H&E and by Prussian blue, which showed sheets of marrow-infiltrating plasma cells and which labeled Gd deposits, respectively. This quantification demonstrated the enhanced sensitivity of NP-SLAMF7 and NP-BCMA, as compared to the passive targeting agents Gd-NP and MagnevistTM, to detect plasma cell populations. As soon as 30 min after the intravenous injection of the nanoparticle-antibody complexes, animals that had been administered NP-SLAMF7 demonstrated an ~3.8-fold increase in the SNR for plasmacytomas in the spine while those that had received NP-BCMA exhibited a ~12-fold enhancement. Note that the NP-BCMA conjugate demonstrated better tumor uptake than NP-SLAMF7 (p= 0.0045, one-sided paired t-test), which was attributed to the greater numbers of surface BCMA antigens on MM cells as assessed on a per cellular basis.We subsequently evaluated their targeting efficiencies both in vitro and in vivo prior to performing a comparative study to determine their detection capabilities when compared to other clinically-available diagnosis, such as computed tomography scans and methods levels of serum lambda light-chains. Comparisons of AUC for the SNR detected by each modality and over the entire duration of the experiment further supported the superiority of the NP-BCMA for both early diagnostic of MM and MRD diagnostic.Selection of alternative cell surface targets may also enable detection of MRD in patients diagnosed with leukemia or other hematological malignancies. Ultra-small nanoparticle-antibody complexes are, thus, poised to impact both the diagnosis and treatment of MM. Their successful application may further afford insights into the fabrication of other targeted constructs that may help translate the full potential of nanomedicines to improve the care and survival of cancer patients. DisclosuresNo relevant conflicts of interest to declare.

Differences in Specific Mass Density Between Dinoflagellate Life Stages and Relevance to Accumulation by Hydrodynamic Processes.

One previously unstudied aspect of differences between sexual and asexual life stages in large‐scale transport and accumulation is density (mass per unit volume) of cells in each life stage. The specific density was determined for Scrippsiella lachrymosa cells in medium with and without nitrogen (N) enrichment through density‐gradient centrifugation. Growth medium without N addition is often called “encystment medium” when used for the purpose of resting cyst formation in cyst‐forming dinoflagellates; mating gametes are usually seen after 2–3 days. Significant differences in specific density were found after 2 days in encystment medium simultaneously with the observation of typical gamete swimming behavior and mating. The specific density of cells in encystment medium was 1.06 g · cm−3; whereas, the specific density of cells in growth medium was 1.11 g · cm−3. Cells in encystment medium were found to have significantly increased lipid content, reduced chlorophyll content, and reduced internal complexity. The findings may explain differential transport of less dense and chemotactically aggregating gametes into surface blooms in contrast to denser vegetative cells that perform daily vertical migration and do not aggregate. Passive accumulation of non‐migrating gametes into layers in stagnant water also can be explained, as well as sinking of zygotes when the storage of highly dense starch increases. Resting cysts had a density of over 1.14 g · cm−3 and would sink to become part of the silt fraction of the sediment. We suggest that differences in behavior and buoyancy between sexual and asexual life stages cause differences in cell accumulation, and therefore large‐scale, environmental transport could be directly dependent upon life‐cycle transitions.

TMTP1-Modified, Tumor Microenvironment Responsive Nanoparticles Co-Deliver Cisplatin and Paclitaxel Prodrugs for Effective Cervical Cancer Therapy.

Background and PurposeCisplatin–paclitaxel (TP) combination chemotherapy as the first-line therapy for numerous cancers is hindered by its inadequate accumulation in tumors and severe side effects resulting from non-specific distribution. The aim of this study is to explore whether TMTP1-modified, cisplatin and paclitaxel prodrugs co-loaded nanodrug could improve cervical cancer chemotherapy and relieve its side effects through active and passive tumor targeting accumulation and controlled drug release.MethodsTDNP, with capacities of active targeting for tumors and controlled drug release, was prepared to co-deliver cisplatin and paclitaxel prodrugs. The characteristics were investigated, including the diameter, surface zeta potential, stability and tumor microenvironment (TME) dependent drug release profiles. Cellular uptake, cytotoxicity, drug accumulation in tumors, antitumor effects and safety analysis were evaluated in vitro and in vivo.ResultsThe oxidized cisplatin and the paclitaxel linked to the polymer achieved a high loading effciency of over 80% and TME-dependent sustained drug release. Moreover, TMTP1 modification enhanced cellular uptake of TDNP and further improved the cytotoxicity of TDNP in vitro. In vivo, TDNP showed an extended blood circulation and increased accumulation in SiHa xenograft models with the aid of TMTP1. More importantly, TDNP controlled tumor growth without life-threatening side effects.ConclusionOur study provided a novel TP co-delivery platform for targeted chemotherapy of cervical cancer, which was promising to improve the therapeutic effcacy of TP and may also have application in other tumors.

Microfluidic design of tumor vasculature and nanoparticle uptake by cancer cells

The most challenging phase in the clinical translation of drugs is the complex process of screening various drugs and evaluating their therapeutic effects in vitro and in vivo. Microfluidic models have been recognized as an interesting alternative to animal models for drug screening. Enhanced permeation and retention (EPR) effect is one of the most widely used standard for drug delivery in solid tumors with high vascular density and active angiogenesis. The nascent blood vessels in the tumor vicinity have large gaps between the endothelial junctions which allow nanoparticles to pass through them, resulting in selective extravasation and passive accumulation in the tumor regions. In this study, an attempt has been made to mimic some of the physiological characteristics in solid tumors such as endothelial gap junctions, obstructed blood vessels and EPR using a microfluidic platform for drug screening under dynamic culture conditions. The microfluidic chip was fabricated using soft lithography technique. Numerical simulations were performed to analyze the flow patterns inside the chip. Fluorescent gold nanoclusters (Au NCs) were synthesized and their accumulation in the tumor cells cultured inside the microfluidic chip was studied. The experimental results showed an increased uptake of Au NCs in the cells near the endothelial gap junctions in comparison to the cells away from the junctions. The observations in the study correlated with the leaky nature of the tumor vasculature, owing to the enhancement of vascularization and thereby EPR effect. Hence, the fabricated microfluidic device has the potential of minimizing the number of pre-clinical trials using animal models, allowing easier drug screening.

Chemerin causes lipid metabolic imbalance and induces passive lipid accumulation in human hepatoma cell line via the receptor GPR1

AimsChemerin is abundant in patients with high body mass index and metabolic syndrome possibly due to its activation in adipogenesis and glucose intolerance. It has reported that sera chemerin is positively associated with fatty liver with little known underlying mechanisms. Our aim is to study the role of chemerin in hepatic lipid metabolism. Main methodsOil Red O staining and TG quantitative assay were used to detect intracellular lipid accumulation. PCR, QPCR and western blot were applied to measure lipid metabolism-related genes, CMKLR1, GPR1 and inflammation marker genes. Luciferase reporter assay was employed to uncover the down-regulation of proximate promoter activities of CMKLR1 and GPR1 by SREBP1c. Antibody neutralization assay was used to address the effects of chemerin on hepatic lipid synthesis. Key findingsOver-expression of chemerin led to passive lipid accumulation, in human hepatoma cell line HepG2. The disable form of chemerin (chemerin 21–158) and active chemerin (chemerin 21–157) performed strongly effects on lipid metabolism in HepG2 cells. Heterologous expression of CMKLR1 or G-protein coupled receptor1 (GPR1) played similar roles in hepatocyte lipid metabolism as chemerin. Chemerin exerted its effects on lipid metabolism via GPR1 in HepG2 cells. Furthermore, free fatty acids and high concentration insulin inhibited chemerin expression. Consistently, the key lipogenic transcription factor Sterol regulatory element binding protein 1c suppressed chemerin mRNA expression and proximate promoter activities of CMKLR1 and GPR1. SignificanceIt implied the existence of negative feed-back regulation and further confirmed the involvement of chemerin in hepatic lipid metabolism.

A comparative study on natural gas hydrate accumulation models at active and passive continental margins

The comparative study on natural gas hydrate accumulation models between active and passive continental margins as well as their controlling factors is of great significance to the guidance of natural gas hydrate exploration. Based on the data and research results of international typical active continental margin hydrate accumulation areas such as the Cascadia margin of the Northeast Pacific, the Nankai trough, etc. and passive continental margin areas like the Blake Ridge, the models of the gas hydrate accumulation system are summarized and numerically simulated, and a preliminary comparison of active and passive continental margin reservoir accumulation models was also carried out. The following results were obtained. (1) The active continental margin provides a driving force and channel for vertical gas migration, which induces deep free gas and in-situ biogas to migrate along the fault. The migration channels are mainly faults, fractures and slumps produced by subduction–accretion. (2) Coarse-grained turbidity sediments such as silt and sandy silt have good porosity and permeability. Moreover, the sediment thickness on the accretionary wedge is large, which provides a good storage space for hydrate accumulation. (3) Numerical simulations of the Blake Ridge, and Niger Delta hydrate accumulation show that the passive continental margin lacks the lateral stress caused by the subduction zone compared with the active continental margin. However, due to the plastic materials in the thick sedimentary layer, high-pressure fluids and volcanic activities outside the continental margin, vertical accretion and tensile stress are generated and the accumulation rate of diffusion-type hydrates mainly depends on the methane supply rate. (4) Organic matter content, gas production rate, geothermal gradient and sedimentation rate at the passive continental margin have different effects on the spatial distribution of hydrate content. Mud volcanoes or diapir structures provide an ideal place for the formation and occurrence of hydrates.

Treatment of Hepatic Fibrosis in Mice Based on Targeted Plasmonic Hyperthermia.

Liver fibrosis is a major health problem with multiple associated complications, which, to date, has no effective treatment. Hepatic stellate cells are the main responsible cells for fibrosis formation; upon their activation, excess accumulation of extracellular matrix and collagen deposits occurs. The mitogen platelet-derived growth factor (PDGF) and its receptor β (PDGFRβ) play a major role in hepatic stellate cells activation and are, therefore, promising targets for antifibrotic therapies. Gold nanorods hold great potential for diseased liver treatments, since their passive hepatic accumulation enhances active targeting strategies, hence increasing therapeutic efficiency. In addition, gold nanorods have photothermal properties that, combined with specific cell delivery, can be exploited to induce localized near-infrared light-mediated thermal ablation. Here, we demonstrate that gold nanorods coated with anti-PDGFRβ specifically target activated hepatic stellate cells in vivo. Additionally, gold nanorods-PDGFRβ-mediated photothermal therapy decreases fibrosis, hepatic inflammation, and hepatocyte injury in the experimental model of CCl4-induced liver fibrosis in mice.

Micellar Drug Delivery Systems Based on Natural Biopolymers.

The broad diversity of structures and the presence of numerous functional groups available for chemical modifications represent an enormous advantage for the development of safe, non-toxic, and cost-effective micellar drug delivery systems (DDS) based on natural biopolymers, such as polysaccharides, proteins, and peptides. Different drug-loading methods are used for the preparation of these micellar systems, but it appeared that dialysis is generally recommended, as it avoids the formation of large micellar aggregates. Moreover, the preparation method has an important influence on micellar size, morphology, and drug loading efficiency. The small size allows the passive accumulation of these micellar systems via the permeability and retention effect. Natural biopolymer-based micellar DDS are high-value biomaterials characterized by good compatibility, biodegradability, long blood circulation time, non-toxicity, non-immunogenicity, and high drug loading, and they are biodegraded to non-toxic products that are easily assimilated by the human body. Even if some recent studies reported better antitumoral effects for the micellar DDS based on polysaccharides than for commercial formulations, their clinical use is not yet generalized. This review is focused on the studies from the last decade concerning the preparation as well as the colloidal and biological characterization of micellar DDS based on natural biopolymers.

In Vivo Fluorescence Imaging of Passive Inflammation Site Accumulation of Liposomes via Intravenous Administration Focused on Their Surface Charge and PEG Modification.

Nanocarriers such as liposomes have been attracting attention as novel therapeutic methods for inflammatory autoimmune diseases such as rheumatoid arthritis and ulcerative colitis. The physicochemical properties of intravenously administered nanomedicines enable them to target inflamed tissues passively. However, few studies have attempted to determine the influences of nanoparticle surface characteristics on inflammation site accumulation. Here, we aimed to study the effects of polyethylene glycol (PEG) modification and surface charge on liposome ability to accumulate in inflammatory sites and be uptake by macrophages. Four different liposome samples with different PEG modification and surface charge were prepared. Liposome accumulation in the inflammation sites of arthritis and ulcerative colitis model mice was evaluated by using in vivo imaging. There was greater PEG-modified than unmodified liposome accumulation at all inflammation sites. There was greater anionic than cationic liposome accumulation at all inflammation sites. The order in which inflammation site accumulation was confirmed was PEG-anionic > PEG-cationic > anionic > cationic. PEG-anionic liposomes had ~2.5× higher fluorescence intensity than PEG-cationic liposomes, and the PEG-liposomes had ~2× higher fluorescence intensity than non-PEG liposomes. All liposomes have not accumulated at the inflammation sites in healthy mice. Furthermore, cationic liposomes were taken up to ~10× greater extent by RAW264.7 murine macrophages. Thus, PEG-cationic liposomes that have the ability to accumulate in inflammatory sites via intravenous administration and to be taken up by macrophages could be useful.

Influence of various water quality parameters on passive sampler accumulation kinetics of different metal valencies in freshwater.

Stabilized liquid membrane devices (SLMDs) have been used for passive integrative sampling of metals in freshwater systems. Field measurements of metal accumulation on SLMDs can provide a time-weighted average mass of labile metals over the deployment period. We exposed SLMDs in the laboratory to 0.5μM solutions of silver, zinc, or aluminum as nitrate salts at three levels of water hardness, measuring metal accumulation every 4days for 32days. We saw linear accumulation in all experimental treatments, except for silver in high hardness (345.9mg/L as CaCO3). The time-accumulation relationships indicated that metal sorption rates vary across valency with the lower valency metals generally accumulating at greater rates. Water hardness also affected accumulation rates and accumulated mass with greater rates as hardness increased for zinc and aluminum. The accumulated zinc mass at 32days in soft water was 78% of the mass in hard water for zinc, and accumulated aluminum mass was 29% of the mass in hard water. Factors such as oleate formation on the SLMD surface and solution chemistry, including pH and chemical speciation, were evaluated in explaining our results. Our work supports that SLMDs have utility for sampling metals in freshwater over extended time periods, which may be beneficial when there is limited access to sites; it also provide important interpretive guidance for the use of SLMDs.

Kissing loop-mediated fabrication of RNA nanoparticles and their potential as cellular and in vivo siRNA delivery platforms.

We describe an efficient method to condense RNAs into tightly packed RNA nanoparticles (RNPs) for biomedical applications without hydrophobic or cationic agents. We embedded kissing loops and siRNA in the RNAs to constrain the size of RNPs to ca. 100 nm, making them suitable not only for cellular uptake but also for passive tumor accumulation. The resulting RNPs were efficiently internalized into cells and downregulated the target gene of siRNAs. When intravenously injected into tumor-bearing mice, RNPs could also accumulate in the tumor. The reported fabrication method could be readily adopted as a platform to prepare RNPs for in vitro and in vivo delivery of bioactive RNAs.

От детской одаренности к реальному таланту: проблема «перехода»

The main problem of gifted children is the "transition" of their increased intellectual capabilities into talent, as the basis of creative activity, or, in another formulation, the transformation of children's giftedness into an actual talent. Analysis of available materials shows that the cognitive need of a significant part of these children takes the character of passive accumulation of a large amount of knowledge and therefore becomes an obstacle to such a transition. The search need is considered to be a basic factor, which is the "engine" of the creative realization of a gifted person, which ensures the search for new solutions and ways of action in contradictory and uncertain situations for the subject, and, thus, becomes the basis of his talent, future creative achievements. It is shown that in a number of gifted children and, above all, in the so-called "prodigies" the need for search is early and very significantly deformed, which in most cases is directly related to social influences. The article deals with the causes and consequences of a significant deformation of the search need in gifted children.

Characterization of the biological, physical, and chemical properties of a toxic thin layer in a temperate marine system

The distribution of plankton in the ocean is patchy across a wide range of spatial and temporal scales. One type of oceanographic feature that exemplifies this patchiness is a ‘thin layer’. Thin layers are subsurface aggregations of plankton that range in vertical thickness from centimeters to a few meters, which may extend horizontally for kilometers and persist for days. We undertook a field campaign to characterize the biological, physical, and chemical properties of thin layers in Monterey Bay, California (USA), an area where these features can be persistent. The particle aggregates (marine snow) sampled in the study had several quantifiable properties indicating how the layer was formed and how its structure was maintained. Particles were more elongated above the layer, and then changed orientation angle and increased in size within the layer, suggesting passive accumulation of particles along a physical gradient. The shift in particle aggregate orientation angle near the pycnocline suggests that shear may also have played a role in generating the thin layer. Pseudo-nitzschia spp. were the most abundant phytoplankton within the thin layer. Further, both dissolved and particulate domoic acid were highest within the thin layer. We suggest that phosphate stress is responsible for the formation of Pseudo-nitzschia spp. aggregates. This stress together with increased nitrogen in the layer may lead to increased bloom toxicity in the subsurface blooms of Pseudo-nitzschia spp. Several zooplankton groups were observed to aggregate above and below the layer. With the knowledge that harmful algal bloom events can occur in subsurface thin layers, modified sampling methods to monitor for these hidden incubators could greatly improve the efficacy of early-warning systems designed to detect harmful algal blooms in coastal waters.

Anti-EGFR liquid crystalline nanodispersions for docetaxel delivery: Formulation, characterization and cytotoxicity in cancer cells

Prostate cancer is one of the most frequent neoplasms, associated with high mortality. Some factors may intensify its aggressiveness, for example, the overexpression of the epidermal growth factor receptor (EGFR) in some subtypes of prostate tumors. In this context, the inhibition of EGFR helps to fight neoplasia, with the use of the chimeric anti-EGFR monoclonal antibody, cetuximab (CTX). For cancer treatment in the metastatic stage, chemotherapy using docetaxel (DTX) is widely employed, however the drug is very liposoluble, hampering its bioavailability. In this sense, liquid crystalline systems have great potential for the delivery of DTX. Particularly, liquid crystalline nanodispersions can be used in parenteral routes, with many advantages, including the possibility of prolonged drug release, improved pharmacokinetics, allowing passive tumor accumulation by the EPR effect. Thus, the objective of this work was to develop a liquid crystalline nanodispersion (LCN) based on ethoxylated cetyl alcohol 20 and propoxylated 5 as surfactant (Procetyl®), oleic acid, DSPE-PEG-MAL (anchor for CTX binding) and soy phosphatidylcholine as oily phase and 1.5 % poloxamer dispersion in PBS buffer as an aqueous phase. The formulation was loaded with DTX and covalently functionalized with CTX to evaluate its cytotoxic potential against prostate cancer cells. The results suggested that the obtained system has a predominantly hexagonal crystalline phase, was able to be nanodispersed with low polydispersity, and presented negative zeta potential. CTX did not have its structure compromised after thiolation and was successfully covalently linked to LCN. In a prostate cancer cells, PC3, LCNs functionalized with CTX underwent greater cell uptake, resulting in greater cytotoxicity, compared to free DTX and non-functionalized DTX-loaded LCNs. Therefore, the present study reports for the first time an EGFR-targeted liquid crystal nanodispersion for selective to deliver DTX to prostate cells

Laser-synthesized TiN nanoparticles for biomedical applications: Evaluation of safety, biodistribution and pharmacokinetics

Having plasmonic absorption within the biological transparency window, titanium nitride (TiN) nanoparticles (NPs) can potentially outperform gold counterparts in phototheranostic applications, but characteristics of available TiN NPs are still far from required parameters. Recently emerged laser-ablative synthesis opens up opportunities to match these parameters as it makes possible the production of ultrapure low size-dispersed spherical TiN NPs, capable of generating a strong phototherapy effect under 750–800 nm excitation. This study presents the first assessment of toxicity, biodistribution and pharmacokinetics of laser-synthesized TiN NPs. Tests in vitro using 8 cell lines from different tissues evidenced safety of both as-synthesized and PEG-coated NPs (TiN-PEG NPs). After systemic administration in mice, they mainly accumulated in liver and spleen, but did not cause any sign of toxicity or organ damage up to concentration of 6 mg kg−1, which was confirmed by the invariability of blood biochemical parameters, weight and hemotoxicity examination. The NPs demonstrated efficient passive accumulation in EMT6/P mammary tumor, while concentration of TiN-PEG NPs was 2.2-fold higher due to “stealth” effect yielding 7-times longer circulation in blood. The obtained results evidence high safety of laser-synthesized TiN NPs for biological systems, which promises a major advancement of phototheranostic modalities on their basis.

Influence of Riboflavin Targeting on Tumor Accumulation and Internalization of Peptostar Based Drug Delivery Systems.

Riboflavin carrier protein (RCP) and riboflavin transporters (RFVTs) have been reported to be highly overexpressed in various cancer cells. Hence, targeting RCP and RFVTs using riboflavin may enhance tumor accumulation and internalization of drug delivery systems. To test this hypothesis, butyl-based 3-arm peptostar polymers were synthesized consisting of a lysine core (10 units per arm) and a sarcosine shell (100 units per arm). The end groups of the arms and the core were successfully modified with riboflavin and the Cy5.5 fluorescent dye, respectively. While in phosphate buffered saline the functionalized peptostars showed a bimodal behavior and formed supramolecular structures over time, they were stable in the serum maintaining their hydrodynamic diameter of 12 nm. Moreover, the polymers were biocompatible and the uptake of riboflavin targeted peptostars in A431 and PC3 cells was higher than in nontargeted controls and could be blocked competitively. In vivo, the polymers showed a moderate passive tumor accumulation, which was not significantly different between targeted and nontargeted peptostars. Nonetheless, at the histological level, internalization into tumor cells was strongly enhanced for the riboflavin-targeted peptostars. Based on these results, we conclude that passive accumulation is dominating the accumulation of peptostars, while tumor cell internalization is strongly promoted by riboflavin targeting.

Say no to drugs: Bioactive macromolecular therapeutics without conventional drugs

The vast majority of nanomedicines (NM) investigated today consists of a macromolecular carrier and a drug payload (conjugated or encapsulated), with a purpose of preferential delivery of the drug to the desired site of action, either through passive accumulation, or by active targeting via ligand-receptor interaction. Several drug delivery systems (DDS) have already been approved for clinical use. However, recent reports are corroborating the notion that NM do not necessarily need to include a drug payload, but can exert biological effects through specific binding/blocking of important target proteins at the site of action. The seminal work of Kopeček et al. on N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers containing biorecognition motifs (peptides or oligonucleotides) for crosslinking cell surface non-internalizing receptors of malignant cells and inducing their apoptosis, without containing any low molecular weight drug, led to the definition of a special group of NM, termed Drug-Free Macromolecular Therapeutics (DFMT). Systems utilizing this approach are typically designed to employ pendant targeting-ligands on the same macromolecule to facilitate multivalent interactions with receptors. The lack of conventional small molecule drugs reduces toxicity and adverse effects at off-target sites.In this review, we describe different types of DFMT that possess biological activity without attached low molecular weight drugs. We classified the relevant research into several groups by their mechanisms of action, and compare the advantages and disadvantages of these different approaches. We show that identification of target sites, specificity of attached targeting ligands, binding affinity and the synthesis of carriers of defined size and ligand spacing are crucial aspects of DFMT development. We further discuss how knowledge in the field of NM accumulated in the past few decades can help in the design of a successful DFMT to speed up the translation into clinical practice.

Evaluation of VCAM-1 Targeted Naringenin/Indocyanine Green-Loaded Lipid Nanoemulsions as Theranostic Nanoplatforms in Inflammation.

Naringenin, an anti-inflammatory citrus flavonoid, is restrained from large-scale use by its reduced water solubility and bioavailability. To overcome these limitations, naringenin was loaded into lipid nanoemulsions directed towards vascular cell adhesion molecule (VCAM)-1, exposed by activated endothelium, and delivered intravenously in a murine model of lipopolysaccharide (LPS)-induced inflammation. To follow the in vivo bio-distribution, naringenin-loaded nanoemulsions were labeled with near-infrared probe Indocyanine Green (ICG). Based on ICG fluorescence, a VCAM-1-dependent retention of nanoemulsions was detected in the heart and aorta, while ultra-high-performance liquid chromatography (UHPLC) measurements showed a target-selective accumulation of naringenin in the heart and lungs. Correlated, fluorescence and UHPLC data indicated a mixed behavior of the VCAM-1 directed nanoparticles, which were driven not only by the targeting moiety but also by passive retention. The treatment with naringenin-loaded nanoemulsions reduced the mRNA levels of some inflammatory mediators in organs harvested from mice with acute inflammation, indicative of their anti-inflammatory potential. The data support a novel theranostic nanoplatform for inflammation, the naringenin/ICG-loaded nanoparticles that either by passive accumulation or effective targeting of the activated endothelium can be employed for imaging inflamed vascular areas and efficient delivery of the encapsulated therapeutic agent.