Significant effect of size on the in vivo biodistribution of gold composite nanodevices in mouse tumor models

Metal-based nanoparticle in cancer treatment: lessons learned and challenges

Cancer, being one of the deadliest diseases, poses significant challenges despite the existence of traditional treatment approaches. This has led to a growing demand for innovative pharmaceutical agents that specifically target cancer cells for effective treatment. In recent years, the use of metal nanoparticles (NPs) as a promising alternative to conventional therapies has gained prominence in cancer research. Metal NPs exhibit unique properties that hold tremendous potential for various applications in cancer treatment. Studies have demonstrated that certain metals possess inherent or acquired anticancer capabilities through their surfaces. These properties make metal NPs an attractive focus for therapeutic development. In this review, we will investigate the applicability of several distinct classes of metal NPs for tumor targeting in cancer treatment. These classes may include gold, silver, iron oxide, and other metals with unique properties that can be exploited for therapeutic purposes. Additionally, we will provide a comprehensive summary of the risk factors associated with the therapeutic application of metal NPs. Understanding and addressing these factors will be crucial for successful clinical translation and to mitigate any potential challenges or failures in the translation of metal NP-based therapies. By exploring the therapeutic potential of metal NPs and identifying the associated risk factors, this review aims to contribute to the advancement of cancer treatment strategies. The anticipated outcome of this review is to provide valuable insights and pave the way for the advancement of effective and targeted therapies utilizing metal NPs specifically for cancer patients.

Surface ligand-regulated renal clearance of MRI/SPECT dual-modality nanoprobes for tumor imaging

BACKGROUND

The general sluggish clearance kinetics of functional inorganic nanoparticles tend to raise potential biosafety concerns for in vivo applications. Renal clearance is a possible elimination pathway for functional inorganic nanoparticles delivered through intravenous injection, but largely depending on the surface physical chemical properties of a given particle apart from its size and shape.

RESULTS

In this study, three small-molecule ligands that bear a diphosphonate (DP) group, but different terminal groups on the other side, i.e., anionic, cationic, and zwitterionic groups, were synthesized and used to modify ultrasmall Fe3O4 nanoparticles for evaluating the surface structure-dependent renal clearance behaviors. Systematic studies suggested that the variation of the surface ligands did not significantly increase the hydrodynamic diameter of ultrasmall Fe3O4 nanoparticles, nor influence their magnetic resonance imaging (MRI) contrast enhancement effects. Among the three particle samples, Fe3O4 nanoparticle coated with zwitterionic ligands, i.e., Fe3O4@DMSA, exhibited optimal renal clearance efficiency and reduced reticuloendothelial uptake. Therefore, this sample was further labeled with 99mTc through the DP moieties to achieve a renal-clearable MRI/single-photon emission computed tomography (SPECT) dual-modality imaging nanoprobe. The resulting nanoprobe showed satisfactory imaging capacities in a 4T1 xenograft tumor mouse model. Furthermore, the biocompatibility of Fe3O4@DMSA was evaluated both in vitro and in vivo through safety assessment experiments.

CONCLUSIONS

We believe that the current investigations offer a simple and effective strategy for constructing renal-clearable nanoparticles for precise disease diagnosis.

Chemical characterization and effect of Ziziphora clinopodioides green-synthesized silver nanoparticles on cytotoxicity, antioxidant, and antidiabetic activities in streptozotocin-induced hepatotoxicity in Wistar diabetic male rats

The present research studied the cytotoxicity, antioxidant, and antidiabetic activities of biogenically synthesized silver nanoparticles (AgNPs) using Ziziphora clinopodioides (Z. clinopodioides) as a green mediator. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and ultraviolet-visible spectroscopy (UV-Vis) were employed to determine AgNPs. In the in vivo experiment, the model rats were categorized into different groups receiving 50, 100, 200, and 400 μg/kg of AgNPs and diabetic, positive, and normal groups (n = 10) using a random division. A single dose of streptozotocin (STZ) at 60 mg/kg was administered to induce diabetes and hepatotoxicity in rats. The administration of AgNPs was performed via intragastric administration for 25 days. On the final day, the levels of glucose and biochemical enzymes, namely aspartate aminotransferase (AST), alkaline phosphatase (ALP), alanine transaminase (ALT), and gamma-glutamyltransferase (GGT), were assessed in the serum. Following tissue processing, liver sections with a thickness of 5 μm were prepared. Later, the total volume of different liver components, such as hepatocytes, sinusoids, portal vein, central vein, hepatic arteries, and bile ducts, was measured. The portal vein and bile duct volumes did not vary significantly in groups treated by AgNPs. However, the volume of the central vein and hepatic arteries exhibited noticeable variations in groups treated by AgNPs. After administration of streptozotocin, the volume of hepatocytes and sinusoids increased significantly. However, treatment with a high dose of AgNPs significantly decreased the volume of hepatocytes and sinusoids. In diabetic rats, administering AgNPs reduced the fasting blood glucose levels compared to the model group. In addition, AgNPs decreased the elevated levels of AST and ALP enzymes in a manner that depended on the dosage of AgNPs used. This research demonstrates the hepatoprotective and antidiabetic properties of AgNPs, suggesting their potential implications as hepatoprotective and antidiabetic supplements to prevent diabetes.

Renal clearable magnetic nanoparticles for magnetic resonance imaging and guided therapy

Magnetic resonance imaging (MRI) is a non-invasive, radiation-free imaging technique widely used for disease detection and therapeutic evaluation due to its infinite penetration depth. Magnetic nanoparticles (MNPs) have unique magnetic and physicochemical properties, making them ideal as contrast agents for MRI. However, the in vivo toxicity of MNPs, resulting from metal ion leakage and long-term accumulation in the reticuloendothelial system (RES), limits their clinical application. To overcome these challenges, there is considerable interest in the development of renal-clearable MNPs that can be completely cleared through the kidney, reducing retention time and potential toxic risks. In this review, we provide an overview of recent advancements in the development of renal-clearable MNPs for disease imaging and treatment. We discuss the factors influencing renal clearance, summarize the types of renal-clearable MNPs, their synthesis methods, and biomedical applications. This review aims to offer comprehensive information for the design and clinical translation of renal-clearable MNPs. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Diagnostic Tools > Biosensing.

Meta-Analysis of Nanoparticle Distribution in Tumors and Major Organs in Tumor-Bearing Mice

Low tumor delivery efficiency is a critical barrier in cancer nanomedicine. This study reports an updated version of "Nano-Tumor Database", which increases the number of time-dependent concentration data sets for different nanoparticles (NPs) in tumors from the previous version of 376 data sets with 1732 data points from 200 studies to the current version of 534 data sets with 2345 data points from 297 studies published from 2005 to 2021. Additionally, the current database includes 1972 data sets for five major organs (i.e., liver, spleen, lung, heart, and kidney) with a total of 8461 concentration data points. Tumor delivery and organ distribution are calculated using three pharmacokinetic parameters, including delivery efficiency, maximum concentration, and distribution coefficient. The median tumor delivery efficiency is 0.67% injected dose (ID), which is low but is consistent with previous studies. Employing the best regression model for tumor delivery efficiency, we generate hypothetical scenarios with different combinations of NP factors that may lead to a higher delivery efficiency of >3%ID, which requires further experimentation to confirm. In healthy organs, the highest NP accumulation is in the liver (10.69%ID/g), followed by the spleen 6.93%ID/g and the kidney 3.22%ID/g. Our perspective on how to facilitate NP design and clinical translation is presented. This study reports a substantially expanded "Nano-Tumor Database" and several statistical models that may help nanomedicine design in the future.

Methods for Radiolabeling Nanoparticles (Part 3): Therapeutic Use

Following previously published systematic reviews on the diagnostic use of nanoparticles (NPs), in this manuscript, we report published methods for radiolabeling nanoparticles with therapeutic alpha-emitting, beta-emitting, or Auger's electron-emitting isotopes. After analyzing 234 papers, we found that different methods were used with the same isotope and the same type of nanoparticle. The most common type of nanoparticles used are the PLGA and PAMAM nanoparticles, and the most commonly used therapeutic isotope is 177Lu. Regarding labeling methods, the direct encapsulation of the isotope resulted in the most reliable and reproducible technique. Radiolabeled nanoparticles show promising results in metastatic breast and lung cancer, although this field of research needs more clinical studies, mainly on the comparison of nanoparticles with chemotherapy.

A 90-day oral exposure to food-grade gold at relevant human doses impacts the gut microbiota and the local immune system in a sex-dependent manner in mice

BACKGROUND

Edible gold (Au) is commonly used as a food additive (E175 in EU) for confectionery and cake decorations, coatings and in beverages. Food-grade gold is most often composed of thin Au sheets or flakes exhibiting micro- and nanometric dimensions in their thickness. Concerns about the impact of mineral particles used as food additives on human health are increasing with respect to the particular physico-chemical properties of nanosized particles, which enable them to cross biological barriers and interact with various body cell compartments. In this study, male and female mice were exposed daily to E175 or an Au nanomaterial (Ref-Au) incorporated into food at relevant human dose for 90 days in order to determine the potential toxicity of edible gold.

RESULTS

E175 or Ref-Au exposure in mice did not induce any histomorphological damage of the liver, spleen or intestine, nor any genotoxic effects in the colon and liver despite an apparent higher intestinal absorption level of Au particles in mice exposed to Ref-Au compared to the E175 food additive. No changes in the intestinal microbiota were reported after treatment with Ref-Au, regardless of sex. In contrast, after E175 exposure, an increase in the Firmicutes/Bacteroidetes ratio and in the abundance of Proteobacteria were observed in females, while a decrease in the production of short-chain fatty acids occurred in both sexes. Moreover, increased production of IL-6, TNFα and IL-1β was observed in the colon of female mice at the end of the 90-day exposure to E175, whereas, decreased IL-6, IL-1β, IL-17 and TGFβ levels were found in the male colon.

CONCLUSIONS

These results revealed that a 90-day exposure to E175 added to the diet alters the gut microbiota and intestinal immune response in a sex-dependent manner in mice. Within the dose range of human exposure to E175, these alterations remained low in both sexes and mostly appeared to be nontoxic. However, at the higher dose, the observed gut dysbiosis and the intestinal low-grade inflammation in female mice could favour the occurrence of metabolic disorders supporting the establishment of toxic reference values for the safe use of gold as food additive.

Radiosensitising effect of iron oxide-gold nanocomplex for electron beam therapy of melanoma in vivo by magnetic targeting

Melanoma is a dangerous type of skin cancer sometimes treated with radiotherapy. However, it induces damage to the surrounding healthy tissue and possibly further away areas. Therefore, it is necessary to give a lower dose to the patient with targeted therapy. In this study, the radio-sensitising effect of gold-coated iron oxide nanoparticles on electron beam radiotherapy of a melanoma tumour with magnetic targeting in a mouse model was investigated. Gold-coated iron oxide nanoparticles were prepared in a steady procedure. The melanoma tumour model was induced in mice. Animals were divided into five groups: (1) normal; (2) melanoma; (3) gold-coated iron oxide nanoparticles alone; (4) electron beam radiotherapy; (5) electron beam radiotherapy plus gold-coated iron oxide nanoparticles. The magnet was placed on the tumour site for 2 h. The tumours were then exposed to 6 MeV electron beam radiotherapy for a dose of 8 Gy. Inductively coupled plasma optical emission spectrometry test, hematoxylin and eosin staining, and enzyme-linked immunosorbent assay blood test were also performed. Gold-coated iron oxide nanoparticles with magnetic targeting before electron beam radiotherapy reduced the growth of the tumour compared to the control group. Blood tests did not show any significant toxicity. Deposition of nanoparticles was more in the tumour and spleen tissue and to a lesser extent in the liver, kidney, and lung tissues. The synergistic effect of nanoparticles administered by the intraperitoneal route and then concentrated into the tumour area by application of an external permanent magnet, before delivery of the electron beam radiotherapy improved the overall cancer treatment outcome and prevented metal distribution side effects.

Nanoparticle biodistribution coefficients: A quantitative approach for understanding the tissue distribution of nanoparticles

The objective of this manuscript is to provide quantitative insights into the tissue distribution of nanoparticles. Published pharmacokinetics of nanoparticles in plasma, tumor and 13 different tissues of mice were collected from literature. A total of 2018 datasets were analyzed and biodistribution of graphene oxide, lipid, polymeric, silica, iron oxide and gold nanoparticles in different tissues was quantitatively characterized using Nanoparticle Biodistribution Coefficients (NBC). It was observed that typically after intravenous administration most of the nanoparticles are accumulated in the liver (NBC = 17.56 %ID/g) and spleen (NBC = 12.1 %ID/g), while other tissues received less than 5 %ID/g. NBC values for kidney, lungs, heart, bones, brain, stomach, intestine, pancreas, skin, muscle and tumor were found to be 3.1 %ID/g, 2.8 %ID/g, 1.8 %ID/g, 0.9 %ID/g, 0.3 %ID/g, 1.2 %ID/g, 1.8 %ID/g, 1.2 %ID/g, 1.0 %ID/g, 0.6 %ID/g and 3.4 %ID/g, respectively. Significant variability in nanoparticle distribution was observed in certain organs such as liver, spleen and lungs. A large fraction of this variability could be explained by accounting for the differences in nanoparticle physicochemical properties such as size and material. A critical overview of published nanoparticle physiologically-based pharmacokinetic (PBPK) models is provided, and limitations in our current knowledge about in vitro and in vivo pharmacokinetics of nanoparticles that restrict the development of robust PBPK models is also discussed. It is hypothesized that robust quantitative assessment of whole-body pharmacokinetics of nanoparticles and development of mathematical models that can predict their disposition can improve the probability of successful clinical translation of these modalities.

Self-assembled hyaluronic acid-coated nanocomplexes for targeted delivery of curcumin alleviate acute kidney injury

Acute kidney injury (AKI) is a pathological process with high morbidity, and drug resistance is easy to occur due to untargeted drug therapy. Curcumin can repair acute kidney injury. The expression of the CD44 receptor in renal tubular epithelial cells is abnormally elevated during AKI, and hyaluronic acid (HA) has the ability to bind specifically to the CD44 receptor. In this study, we developed a hyaluronic acid-coated liposome (HALP) nanocomplexes that targeted renal epithelial cells and its effect of relieving AKI was investigated. HALP was formed by self-assembly through the electrostatic interaction of curcumin-loaded cationic liposomes (LP) with hyaluronic acid and responds to the release of curcumin in the acidic microenvironment of lesions to treat AKI. HALP had good stability and biocompatibility. The in vitro results showed that compared to LP, HALP exhibited higher antioxidant, anti-inflammatory, and anti-apoptotic capacities. The AKI model suggested that HALP could not only target and accumulate in the injured kidney but also had an excellent ability to reduce the inflammatory response, which decreased tubular necrosis and restored kidney function.

Role of Surface Charge of Nanoscale Ultrasound Contrast Agents in Complement Activation and Phagocytosis

Purpose

To prepare nanoscale ultrasound contrast agents (Nano-UCAs) and examine the role of their surface charge in complement activation and phagocytosis.

Materials and Methods

We analyzed serum proteins present in the corona formed on Nano-UCAs and evaluated two important protein markers of complement activation (C3 and SC5b-9). The effect of surface charge on phagocytosis was further assessed using THP-1 macrophages.

Results

When Nano-UCAs were incubated with human serum, they were opsonized by various blood proteins, especially C3. Highly charged Nano-UCAs, whether positive or negative, were favorably opsonized by complement proteins and phagocytized by macrophages.

Conclusion

Charged Nano-UCAs show a higher tendency to activated complement system, and are efficiently engulfed by macrophages. The present results provide meaningful insights into the role of the surface charge of nanoparticles in the activation of the innate immune system, which is important not only for the design of targeted Nano-UCAs, but also for the effectiveness and safety of other theranostic agents.

In vitro and in vivo acute toxicity of a novel citrate-coated magnetite nanoparticle

Magnetic nanoparticles (MNps) have become powerful tools for multiple biomedical applications such as hyperthermia drivers, magnetic resonance imaging (MRI) vectors, as well as drug-delivery systems. However, their toxic effects on human health have not yet been fully elucidated, especially in view of their great diversity of surface modifications and functionalizations. Citrate-coating of MNps often results in increased hydrophilicity, which may positively impact their performance as drug-delivery systems. Nonetheless, the consequences on the intrinsic toxicity of such MNps are unpredictable. Herein, novel magnetite (Fe3O4) nanoparticles covered with citrate were synthesized and their potential intrinsic acute toxic effects were investigated using in vitro and in vivo models. The proposed synthetic pathway turned out to be simple, quick, inexpensive, and reproducible. Concerning toxicity risk assessment, these citrate-coated iron oxide nanoparticles (IONps) did not affect the in vitro viability of different cell lines (HaCaT and HepG2). Moreover, the in vivo acute dose assay (OECD test guideline #425) showed no alterations in clinical parameters, relevant biochemical variables, or morphological aspects of vital organs (such as brain, liver, lung and kidney). Iron concentrations were slightly increased in the liver, as shown by Graphite Furnace Atomic Absorption Spectrometry and Perls Prussian Blue Staining assays, but this finding was considered non-adverse, given the absence of accompanying functional/clinical repercussions. In conclusion, this study reports on the development of a simple, fast and reproducible method to obtain citrate-coated IONps with promising safety features, which may be used as a drug nanodelivery system in the short run. (263 words).

Gold Nanoparticles Disrupt the IGFBP2/mTOR/PTEN Axis to Inhibit Ovarian Cancer Growth

By exploiting the self-therapeutic properties of gold nanoparticles (GNPs) a molecular axis that promotes the growth of high-grade serous ovarian cancer (HGSOC), one of the deadliest gynecologic malignancies with poorly understood underlying molecular mechanisms, has been identified. The biodistribution and toxicity of GNPs administered by intravenous or intraperitoneal injection, both as a single dose or by repeated dosing over two weeks are first assessed; no biochemical or histological toxicity to vital organs is found. Using an orthotopic patient-derived xenograft (PDX) model of HGSOC, the authors then show that GNP treatment robustly inhibits tumor growth. Investigating the molecular mechanisms underlying the GNP efficacy reveals that GNPs downregulate insulin growth factor binding protein 2 (IGFBP2) by disrupting its autoregulation via the IGFBP2/mTOR/PTEN axis. This mechanism is validated by treating a cell line-based human xenograft tumor with GNPs and an mTOR dual-kinase inhibitor (PI-103), either individually or in combination with GNPs; GNP and PI-103 combination therapy inhibit ovarian tumor growth similarly to GNPs alone. This report illustrates how the self-therapeutic properties of GNPs can be exploited as a discovery tool to identify a critical signaling axis responsible for poor prognosis in ovarian cancer and provides an opportunity to interrogate the axis to improve patient outcomes.

Ultrasmall-in-Nano: Why Size Matters

Gold nanoparticles (AuNPs) are continuing to gain popularity in the field of nanotechnology. New methods are continuously being developed to tune the particles' physicochemical properties, resulting in control over their biological fate and applicability to in vivo diagnostics and therapy. This review focuses on the effects of varying particle size on optical properties, opsonization, cellular internalization, renal clearance, biodistribution, tumor accumulation, and toxicity. We review the common methods of synthesizing ultrasmall AuNPs, as well as the emerging constructs termed ultrasmall-in-nano-an approach which promises to provide the desirable properties from both ends of the AuNP size range. We review the various applications and outcomes of ultrasmall-in-nano constructs in vitro and in vivo.

Recent progress in the applications of gold-based nanoparticles towards tumor-targeted imaging and therapy

Cancer death rate remains high all over the world, scientists are paying increasing attention to meet the requirements for precise diagnosis and therapy. Therefore, early diagnosis and active treatment can effectively improve the five-year survival rate of patients. In recent years, gold-based nanomaterials have received increasing attention in medical fields due to their excellent biocompatibility, low toxicity and unique properties. In addition, because of the inherent nature of gold nanomaterials including for computed tomography (CT), fluorescence/optical imaging (FI/OI), surface enhanced Raman spectroscopy imaging (SERS), photoacoustic imaging (PAI) and photothermal therapy (PTT), various gold nanomaterials were developed as theranostic nanoplatforms. In this review, we summarized the latest developments of nanomaterials in imaging and combined therapy, and the prospects for the future application of gold-based theranostic nanoplatforms were also proposed.

Renal Nano-drug delivery for acute kidney Injury: Current status and future perspectives

Acute kidney injury (AKI) causes considerable morbidity and mortality, particularly in the case of post-cardiac infarction or kidney transplantation; however, the site-specific accumulation of small molecule reno-protective agents for AKI has often proved ineffective due to dynamic fluid and solute excretion and non-selectivity, which impedes therapeutic efficacy. This article reviews the current status and future trajectories of renal nanomedicine research for AKI management from pharmacological and clinical perspectives, with a particular focus on appraising nanosized drug carrier (NDC) use for the delivery of reno-protective agents of different pharmacological classes and the effectiveness of NDCs in improving renal tissue targeting selectivity and efficacy of said agents. This review reveals the critical shift in the role of the small molecule reno-protective agents in AKI pharmacotherapy - from prophylaxis to treatment - when using NDCs for delivery to the kidney. We also highlight the need to identify the accumulation sites of NDCs carrying reno-protective agents in renal tissues during in vivo assessments and detail the less-explored pharmacological classes of reno-protective agents whose efficacies may be improved via NDC-based delivery. We conclude the paper by outlining the challenges and future perspectives of NDC-based reno-protective agent delivery for better clinical management of AKI.

Gold Nanoparticles; Potential Nanotheranostic Agent in Breast Cancer: A Comprehensive Review with Systematic Search Strategy

BACKGROUND

Breast cancer is a heterogeneous disease typically prevalent among women and is the second-largest cause of death worldwide. Early diagnosis is the key to minimize the cancer-induced complication, however, the conventional diagnostic strategies have been sluggish, complex, and, to some extent, non-specific. Therapeutic tools are not so convenient and side effects of current therapies offer the development of novel theranostic tool to combat this deadly disease.

OBJECTIVE

This article aims to summarize the advances in the diagnosis and treatment of breast cancer with gold nanoparticles (GNP or AuNP).

METHODS

A systematic search was conducted in the three popular electronic online databases including PubMed, Google Scholar, and Web of Science, regarding GNP as breast cancer theranostics.

RESULTS

Published literature demonstrated that GNPs tuned with photosensitive moieties, nanomaterials, drugs, peptides, nucleotide, peptides, antibodies, aptamer, and other biomolecules improve the conventional diagnostic and therapeutic strategies of breast cancer management with minimum cytotoxic effect. GNP derived diagnosis system assures reproducibility, reliability, and accuracy cost-effectively. Additionally, surface-modified GNP displayed theranostic potential even in the metastatic stage of breast cancer.

CONCLUSION

Divergent strategies have shown the theranostic potential of surface tuned GNPs against breast cancer even in the metastatic stage with minimum cytotoxic effects both in vitro and in vivo.

In vivo Bio-Distribution and Toxicity Evaluation of Polymeric and Lipid-Based Nanoparticles: A Potential Approach for Chronic Diseases Treatment

INTRODUCTION

Nanoparticles (NPs), as drug delivery systems, appear to be a promising tool for prolonged therapeutic strategies as they allow a controlled drug release over time. However, most of the studies found in the literature simply contemplate the use of a single or low number of dosages with low NPs concentrations. In the context of chronic diseases, like Alzheimer's disease, cancer or human immunodeficiency virus (HIV), where the therapeutic scheme is also chronic, studies with numerous repeated dosages are often neglected.

METHODS

We screened different NPs, polymeric and lipid-based, in a repeated-dose toxicity study, to evaluate the safety and tissue distribution of promising nanocarriers to be used in the treatment of long-lasting diseases.

RESULTS

After administrating 24 high concentrated doses of the selected NPs intraperitoneally (i.p.) (3 times a week for 2 months), animals have presented NPs accumulation in different tissues. However, neither toxicity, bodyweight changes nor clinical signs of disease were observed.

DISCUSSION

This work demonstrates no general adverse effects upon the studied NPs repeated-dose exposure, indicating the most promising NPs to be used in the different therapeutic circumstances, which may be useful in chronic diseases treatment.

A framework for designing delivery systems

The delivery of medical agents to a specific diseased tissue or cell is critical for diagnosing and treating patients. Nanomaterials are promising vehicles to transport agents that include drugs, contrast agents, immunotherapies and gene editors. They can be engineered to have different physical and chemical properties that influence their interactions with their biological environments and delivery destinations. In this Review Article, we discuss nanoparticle delivery systems and how the biology of disease should inform their design. We propose developing a framework for building optimal delivery systems that uses nanoparticle-biological interaction data and computational analyses to guide future nanomaterial designs and delivery strategies.

The effect of size, charge, and peptide ligand length on kidney targeting by small, organic nanoparticles

Chronic kidney disease (CKD) affects 15% of the US adult population. However, most clinically available drugs for CKD show low bioavailability to the kidneys and non-specific uptake by other organs which results in adverse side effects. Hence, a targeted, drug delivery strategy to enhance kidney drug delivery is highly desired. Recently, our group developed small, organic nanoparticles called peptide amphiphile micelles (PAM) functionalized with the zwitterionic peptide ligand, (KKEEE)3K, that passage through the glomerular filtration barrier for kidney accumulation. Despite high bioavailability to the kidneys, these micelles also accumulated in the liver to a similar extent. To further optimize the physicochemical properties and develop design rules for kidney-targeting micelles, we synthesized a library of PAMs of varying size, charge, and peptide repeats. Specifically, variations of the original (KKEEE)3K peptide including (KKEEE)2K, (KKEEE)K, (EEKKK)3E, (EEKKK)2E, (EEKKK)E, KKKKK, and EEEEE were functionalized onto nanoparticles, and peptide surface density and PEG linker molecular weight were altered. After characterization with transmission electron microscopy (TEM) and dynamic light scattering (DLS), nanoparticles were intravenously administered into wildtype mice, and biodistribution was assessed through ex vivo imaging. All micelles localized to the kidneys, but nanoparticles that are positively-charged, close to the renal filtration size cut-off, and consisted of additional zwitterionic peptide sequences generally showed higher renal accumulation. Upon immunohistochemistry, micelles were confirmed to bind to the multiligand receptor, megalin, and histological analyses showed no tissue damage. Our study provides insight into the design of micelle carriers for kidney targeting and their potential for future therapeutic application.

Gold nanospheres and nanorods for anti-cancer therapy: comparative studies of fabrication, surface-decoration, and anti-cancer treatments

Various gold nanoparticles have been explored as cancer therapeutics because they can be widely engineered for use as efficient drug carriers and diagnostic agents, and in photo-irradiation therapy. In the current review, we focused on shape-dependent biomedical applications of gold nanoparticles including gold nanospheres and nanorods. Fabrication and functionalization strategies of two different gold nanoparticles for anti-cancer therapy are introduced and the distinguishing performance depending on the shape is discussed to suggest the best carrier shape for specific applications. Moreover, recent advances in anti-cancer immunotherapy using gold nano-carriers are discussed. Thus, this comparative review can be helpful in deciding on suitable shapes and surface-modification strategies for preparing various gold nanoparticle-based therapeutics in anti-cancer therapy.

Meta-Analysis of Nanoparticle Delivery to Tumors Using a Physiologically Based Pharmacokinetic Modeling and Simulation Approach

Numerous studies have engineered nanoparticles with different physicochemical properties to enhance the delivery efficiency to solid tumors, yet the mean and median delivery efficiencies are only 1.48% and 0.70% of the injected dose (%ID), respectively, according to a study using a nonphysiologically based modeling approach based on published data from 2005 to 2015. In this study, we used physiologically based pharmacokinetic (PBPK) models to analyze 376 data sets covering a wide range of nanomedicines published from 2005 to 2018 and found mean and median delivery efficiencies at the last sampling time point of 2.23% and 0.76%ID, respectively. Also, the mean and median delivery efficiencies were 2.24% and 0.76%ID at 24 h and were decreased to 1.23% and 0.35%ID at 168 h, respectively, after intravenous administration. While these delivery efficiencies appear to be higher than previous findings, they are still quite low and represent a critical barrier in the clinical translation of nanomedicines. We explored the potential causes of this poor delivery efficiency using the more mechanistic PBPK perspective applied to a subset of gold nanoparticles and found that low delivery efficiency was associated with low distribution and permeability coefficients at the tumor site (P < 0.01). We also demonstrate how PBPK modeling and simulation can be used as an effective tool to investigate tumor delivery efficiency of nanomedicines.

Endocytosis mechanism in physiologically-based pharmacokinetic modeling of nanoparticles

BACKGROUND

The physiologically based pharmacokinetic (PBPK) model is a useful tool to predict the pharmacokinetics of various types of nanoparticles (NPs). The endocytosis mechanism plays a key role in pharmacokinetics of NPs. However, the effect of endocytosis mechanism both in the blood and tissue are seldom considered in PBPK model.

OBJECTIVES

To investigate the biodistribution of intravenously injected pegylated AuNPs in mice and human using PBPK model considering the endocytosis mechanism both in the blood and tissue.

METHODS

Taking polyethylene glycol-coated gold nanoparticles (AuNPs) as an example, we developed a PBPK model to explore biodistribution of different size AuNPs. In the model, we considered the role of endocytosis mechanism both in the blood and tissue. In addition, the size-dependent permeability coefficient, excretion rate constant, phagocytic capacity, uptake rate, and release rate were derived from literatures. The mice PBPK model was extrapolated to the human by changing physiology parameters and the number of phagocytic cell (PCs).

RESULTS

AuNPs were primarily distributed in the blood, liver, and spleen regardless of particle size, and almost all captured by the PCs in the liver and spleen, while few was captured in the blood. There are more organ distribution and longer circulation for smaller NPs. The 24-h accumulation of AuNPs decreased with increasing size in the most organ, while the accumulation of AuNPs showed an inverted U-shaped curve in the liver and slight U-shaped curve in the blood. The human results of model-predicted displayed a similar tendency with those in mice. Size, partition coefficients, and body weight were the key factors influencing the organ distribution of AuNPs.

CONCLUSIONS

The size played an important role on the distribution and accumulation of AuNPs in various tissues. Our PBPK model was well predicted the NPs distribution in mice and human. A better understanding of these mechanisms could provide effective guides for nanomedine delivery.

Recent Advances in Nanomaterials-Based Chemo-Photothermal Combination Therapy for Improving Cancer Treatment

Conventional chemotherapy for cancer treatment is usually compromised by shortcomings such as insufficient therapeutic outcome and undesired side effects. The past decade has witnessed the rapid development of combination therapy by integrating chemotherapy with hyperthermia for enhanced therapeutic efficacy. Near-infrared (NIR) light-mediated photothermal therapy, which has advantages such as great capacity of heat ablation and minimally invasive manner, has emerged as a powerful approach for cancer treatment. A variety of nanomaterials absorbing NIR light to generate heat have been developed to simultaneously act as carriers for chemotherapeutic drugs, contributing as heat trigger for drug release and/or inducing hyperthermia for synergistic effects. This review aims to summarize the recent development of advanced nanomaterials in chemo-photothermal combination therapy, including metal-, carbon-based nanomaterials and particularly organic nanomaterials. The potential challenges and perspectives for the future development of nanomaterials-based chemo-photothermal therapy were also discussed.

Environmental Nanoparticle-Induced Toughening and Pinning of a Growing Crack in a Biopolymer Hydrogel

We study the interplay between a crack tip slowly propagating through a hydrogel and nanoparticles suspended in its liquid environment. Using a proteinic gel enables us to tune the electrostatic interaction between the network and silica colloids. Thereby, we unveil two distinct, local toughening mechanisms. The primary one is charge independent and involves the convective building of a thin particulate clog, hindering polymer hydration in the crack process zone. When particles and network bear opposite charges, transient adhesive bonding superimposes, permitting the remarkable pinning of a crack by a liquid drop.

Toward Smaller Aqueous-Phase Plasmonic Gold Nanoparticles: High-Stability Thiolate-Protected ∼4.5 nm Cores

Most applications of aqueous plasmonic gold nanoparticles benefit from control of the core size and shape, control of the nature of the ligand shell, and a simple and widely applicable preparation method. Surface functionalization of such nanoparticles is readily achievable but is restricted to water-soluble ligands. Here we have obtained highly monodisperse and stable smaller aqueous gold nanoparticles (core diameter ∼4.5 nm), prepared from citrate-tannate precursors via ligand exchange with each of three distinct thiolates: 11-mercaptoundecanoic acid, α-R-lipoic acid, and para-mercaptobenzoic acid. These are characterized by UV-vis spectroscopy for plasmonic properties; Fourier transform infrared (FTIR) spectroscopy for ligand-exchange confirmation; X-ray diffractometry for structural analysis; and high-resolution transmission electron microscopy for structure and size determination. Chemical reduction induces a blueshift, maximally +0.02 eV, in the localized surface plasmon resonance band; this is interpreted as an electronic (-) charging of the monolayer-protected cluster (MPC) gold core, corresponding to a -0.5 V change in electrochemical potential.

Probing the biological obstacles of nanomedicine with gold nanoparticles

Despite massive growth in nanomedicine research to date, the field still lacks fundamental understanding of how certain physical and chemical features of a nanoparticle affect its ability to overcome biological obstacles in vivo and reach its intended target. To gain fundamental understanding of how physical and chemical parameters affect the biological outcomes of administered nanoparticles, model systems that can systematically manipulate a single parameter with minimal influence on others are needed. Gold nanoparticles are particularly good model systems in this case as one can synthetically control the physical dimensions and surface chemistry of the particles independently and with great precision. Additionally, the chemical and physical properties of gold allow particles to be detected and quantified in tissues and cells with high sensitivity. Through systematic biological studies using gold nanoparticles, insights toward rationally designed nanomedicine for in vivo imaging and therapy can be obtained. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

Gold Nanoparticles for Photothermal Cancer Therapy

Gold is a multifunctional material that has been utilized in medicinal applications for centuries because it has been recognized for its bacteriostatic, anticorrosive, and antioxidative properties. Modern medicine makes routine, conventional use of gold and has even developed more advanced applications by taking advantage of its ability to be manufactured at the nanoscale and functionalized because of the presence of thiol and amine groups, allowing for the conjugation of various functional groups such as targeted antibodies or drug products. It has been shown that colloidal gold exhibits localized plasmon surface resonance (LPSR), meaning that gold nanoparticles can absorb light at specific wavelengths, resulting in photoacoustic and photothermal properties, making them potentially useful for hyperthermic cancer treatments and medical imaging applications. Modifying gold nanoparticle shape and size can change their LPSR photochemical activities, thereby also altering their photothermal and photoacoustic properties, allowing for the utilization of different wavelengths of light, such as light in the near-infrared spectrum. By manufacturing gold in a nanoscale format, it is possible to passively distribute the material through the body, where it can localize in tumors (which are characterized by leaky blood vessels) and be safely excreted through the urinary system. In this paper, we give a quick review of the structure, applications, recent advancements, and potential future directions for the utilization of gold nanoparticles in cancer therapeutics.

Pharmacokinetics, Tissue Distribution and Excretion of Ag2S Quantum Dots in Mice and Rats: the Effects of Injection Dose, Particle Size and Surface Charge

PURPOSE

We systematically investigated the effects of injection dose, particle size and surface charge on the pharmacokinetics, tissue distribution and excretion of Ag₂S quantum dots (Qds) in rats and mice.

METHODS

Three different doses of Ag₂S Qds with similar size and composition were administrated to rats and mice. The effect of size and surface charge was investigated with the injection of three sizes (5, 15 and 25 nm) of Ag₂S Qds possessing similar surface charge, as well as 5 nm Qds with a positive surface charge.

RESULTS

Results indicated that pharmacokinetics and biodistribution of Ag₂S Qds were strongly dose, particle size and surface charge dependent. By increasing the dose from 0.5 to 4.0 mg/kg, mean residence time (MRT) and apparent volume of distribution at steady state (V_ss) were increased while clearance (CL) was decreased. Qds with a negative surface charge had significantly larger MRT and V_ss values than positively charged particles, but their CL was about 50% lower than that of positively charged ones. By increasing Qds size from 5 to 25 nm, CL was increased while MRT and AUC were decreased.

CONCLUSIONS

This study establishes comprehensive principles for the rational design and tailoring of Ag₂S Qds for biomedical applications. Graphical Abstract The effects of injection dose, particle size and surface charge on pharmacokinetics and tissue distribution of Ag₂S Qds after intravenous injection into rats and mice were investigated.

Laparoscopic fluorescence image-guided photothermal therapy enhances cancer diagnosis and treatment

Endoscopy is the gold standard investigation in the diagnosis of gastrointestinal cancers and the management of early and pre-malignant lesions either by resection or ablation. Recently gold nanoparticles have shown promise in cancer diagnosis and therapeutics (theranostics). The combination of multifunctional gold nanoparticles with near infrared fluorescence endoscopy for accurate mapping of early or pre-malignant lesions can potentially enhance diagnostic efficiency while precisely directing endoscopic near infrared photothermal therapy for established cancers. The integration of endoscopy with near infrared fluorescence imaging and photothermal therapy was aided by the accumulation of our multifunctionalized PEG-GNR-Cy5.5-anti-EGFR-antibody gold nanorods within gastrointestinal tumor xenografts in BALB/c mice. Control mice (with tumors) received either gold nanorods or photothermal therapy, while study mice received both treatment modalities. Local (tumor-centric) and systemic effects were examined for 30 days. Clear endoscopic near infrared fluorescence signals were observed emanating specifically from tumor sites and these corresponded precisely to the tumor margins. Endoscopic fluorescence-guided near infrared photothermal therapy successfully induced tumor ablations in all 20 mice studied, with complete histological clearance and minimal collateral damage. Multi-source analysis from histology, electron microscopy, mass spectrometry, blood, clinical evaluation, psychosocial and weight monitoring demonstrated the inherent safety of this technology. The combination of this innovative nanotechnology with gold standard clinical practice will be of value in enhancing the early optical detection of gastrointestinal cancers and a useful adjunct for its therapy.

Molecular-Level "Observations" of the Behavior of Gold Nanoparticles in Aqueous Solution and Interacting with a Lipid Bilayer Membrane

We use coarse-grained molecular dynamics simulations to "observe" details of interactions between ligand-covered gold nanoparticles and a lipid bilayer model membrane. In molecular dynamics simulations, one puts the individual atoms and groups of atoms of the physical system to be "observed" into a simulation box, specifies the forms of the potential energies of interactions between them (ultimately quantum based), and lets them individually move classically according to Newton's equations of motion, based on the forces arising from the assumed potential energy forms. The atoms that are chemically bonded to each other stay chemically bonded, following known potentials (force fields) that permit internal degrees of freedom (internal rotation, torsion, vibrations), and the interactions between nonbonded atoms are simplified to Lennard-Jones forms (in our case) and coulombic (where electrical charges are present) in which the parameters are previously optimized to reproduce thermodynamic properties or are based on quantum electronic calculations. The system is started out at a reasonable set of coordinates for all atoms or groups of atoms, and then permitted to develop according to the equations of motion, one small step (usually 10 fs time step) at a time, for millions of steps until the system is at a quasi-equilibrium (usually reached after hundreds of nanoseconds). We then let the system play out its motions further for many nanoseconds to observe the behavior, periodically taking snapshots (saving all positions and energies), and post-processing the snapshots to obtain various average descriptions of the system. Alkanethiols of various lengths serve as examples of hydrophobic ligands and methyl-terminated PEG with various numbers of monomer units serve as examples of hydrophilic ligands. Spherical gold particles of various diameters as well as gold nanorods form the core to which ligands are attached. The nanoparticles are characterized at the molecular level, especially the distributions of ligand configurations and their dependence on ligand length, and surface coverage. Self-assembly of the bilayer from an isotropic solution and observation of membrane properties that correspond well to experimental values validate the simulations. The mechanism of permeation of a gold NP coated with either a hydrophobic or a hydrophilic ligand, and its dependence on surface coverage, ligand length, core diameter, and core shape, is investigated. Lipid response such as lipid flip-flops, lipid extraction, and changes in order parameter of the lipid tails are examined in detail. The mechanism of permeation of a PEGylated nanorod is shown to occur by tilting, lying down, rotating, and straightening up. The nature of the information provided by molecular dynamics simulations permits understanding of the detailed behavior of gold nanoparticles interacting with lipid membranes which in turn helps to understand why some known systems work better than others and aids the design of new particles and improvement of methods for preparing existing ones.

A multifunctional low-generation dendrimer-based nanoprobe for the targeted dual mode MR/CT imaging of orthotopic brain gliomas

An RGD peptide-targeted low-generation dendrimer nanoprobe can cross the blood-brain barrier for dual-modal MR/CT imaging of an orthotopic brain glioma.

Lifetime-Encoded Infrared-Emitting Nanoparticles for in Vivo Multiplexed Imaging

Advanced diagnostic procedures are required to satisfy the continuously increasing demands of modern biomedicine while also addressing the need for cost reduction in public health systems. The development of infrared luminescence-based techniques for in vivo imaging as reliable alternatives to traditional imaging enables applications with simpler and more cost-effective apparatus. To further improve the information provided by in vivo luminescence images, the design and fabrication of enhanced infrared-luminescent contrast agents is required. In this work, we demonstrate how simple dopant engineering can lead to infrared-emitting rare-earth-doped nanoparticles with tunable (0.1-1.5 ms) and medium-independent luminescence lifetimes. The combination of these tunable nanostructures with time-gated infrared imaging and time domain analysis is employed to obtain multiplexed in vivo images that are used for complex biodistribution studies.

Investigation of Effective Parameters on Size of Paclitaxel Loaded PLGA Nanoparticles

Purpose: The size of polymeric nanoparticles is considered as an effective factor in cancer therapy due to enterance into tumor tissue via the EPR effect. The purpose of this work was to investigate the effective parameters on poly(lactic-co-glycolic acid)-paclitaxel (PLGA –PTX) nanoparticles size.

Methods: We prepared PLGA-PTX nanoparticles via single emulsion and precipitation methods with variable paremeters including drug concentration, aqueous to organic phase volume ratio, polymer concentration, sonication time and PVA concentration.

Results: PLGA-PTX nanoparticles were characterized by dynamic light scattering (DLS) and scanning electron microscopy (SEM). The results exhibited that the diameter of nanoparticles enhanced with increasing drug, polymer and PVA concentrations whereas organic to aqueous phase volume ratio and sonication time required to the optimization for a given size.

Conclusion: The precipitation method provides smaller nanoparticles compared to emulsion one. Variable parameters including drug concentration, aqueous to organic phase volume ratio, polymer concentration, sonication time and PVA concentration affect diameter of nanoparticles.

Short-wave near-infrared emissive GdPO4:Nd3+theranostic probe forin vivobioimaging beyond 1300 nm

The optical probes working in the second near-infrared (NIR-II) window have attracted increasing research interest for their advantages of high tissue penetration depth, low autofluorescence, and unprecedentedly improved imaging sensitivity and spatial resolution. Therefore, it is of great significance to design a new nanoplatform by integration of NIR-II optical imaging and drug delivery functions. Herein, a multifunctional nanoplatform based on GdPO₄:Nd³⁺ yolk–shell sphere was developed for dual-modal in vivo NIR-II/X-ray bioimaging and pH-responsive drug delivery. The in vivo NIR-II bioimaging and real-time tracking presented that these probes were mainly accumulated in liver and spleen. Moreover, owing to the large X-ray absorption coefficient of Gd³⁺, these probes are successfully used as superior X-ray imaging agents than iobitridol. The in vivo toxicity assessments demonstrate the low biotoxicity of the GdPO₄:Nd³⁺ spheres in living animals. More importantly, apart from the excellent dual-modal bioimaging, these yolk–shell-structured probes were also used as ideal nanotransducer for pH-responsive drug delivery of doxorubicin (DOX). These findings open up the opportunity of designing theranostic nanoplatform with integration of imaging-based diagnosis and therapy.

A multifunctional theranostic nanoplatform based on GdPO₄:Nd³⁺ yolk–shell sphere was developed for dual-modal in vivo NIR-II/X-ray bioimaging and pH-responsive drug delivery.

Toxicity Assessment in the Nanoparticle Era

The wide use of engineered nanomaterials in many fields, ranging from biomedical, agriculture, environment, cosmetic, urged the scientific community to understand the processes behind their potential toxicity, in order to develop new strategies for human safety. As a matter of fact, there is a big discrepancy between the increased classes of nanoparticles and the consequent applications versus their toxicity assessment. Nanotoxicology is defined as the science that studies the effects of engineered nanodevices and nanostructures in living organisms. This chapter analyzes the physico-chemical properties of the most used nanoparticles, the way they enter the living organism and their cytoxicity mechanisms at cellular exposure level. Moreover, the current state of nanoparticles risk assessment is reported and analyzed.

Biological safety and tissue distribution of (16-mercaptohexadecyl)trimethylammonium bromide-modified cationic gold nanorods

The exceptionally high cellular uptake of gold nanorods (GNRs) bearing cationic surfactants makes them a promising tool for biomedical applications. Given the known specific toxic and stress effects of some preparations of cationic nanoparticles, the purpose of this study was to evaluate, in an in vitro and in vivo in mouse, the potential harmful effects of GNRs coated with (16-mercaptohexadecyl)trimethylammonium bromide (^MTABGNRs). Interestingly, even after cellular accumulation of high amounts of ^MTABGNRs sufficient for induction of photothermal effect, no genotoxicity (even after longer-term accumulation), induction of autophagy, destabilization of lysosomes (dominant organelles of their cellular destination), alterations of actin cytoskeleton, or in cell migration could be detected in vitro. In vivo, after intravenous administration, the majority of GNRs accumulated in mouse spleen followed by lungs and liver. Microscopic examination of the blood and spleen showed that GNRs interacted with white blood cells (mononuclear and polymorphonuclear leukocytes) and thrombocytes, and were delivered to the spleen red pulp mainly as GNR-thrombocyte complexes. Importantly, no acute toxic effects of ^MTABGNRs administered as 10 or 50 μg of gold per mice, as well as no pathological changes after their high accumulation in the spleen were observed, indicating good tolerance of ^MTABGNRs by living systems.

Analyses in zebrafish embryos reveal that nanotoxicity profiles are dependent on surface-functionalization controlled penetrance of biological membranes

Mesoporous silica nanoparticles (MSNs) are extensively explored as drug delivery systems, but in depth understanding of design-toxicity relationships is still scarce. We used zebrafish (Danio rerio) embryos to study toxicity profiles of differently surface functionalized MSNs. Embryos with the chorion membrane intact, or dechoroniated embryos, were incubated or microinjected with amino (NH₂-MSNs), polyethyleneimine (PEI-MSNs), succinic acid (SUCC-MSNs) or polyethyleneglycol (PEG-MSNs) functionalized MSNs. Toxicity was assessed by viability and cardiovascular function. NH₂-MSNs, SUCC-MSNs and PEG-MSNs were well tolerated, 50 µg/ml PEI-MSNs induced 100% lethality 48 hours post fertilization (hpf). Dechoroniated embryos were more sensitive and 10 µg/ml PEI-MSNs reduced viability to 5% at 96hpf. Sensitivity to PEG- and SUCC-, but not NH₂-MSNs, was also enhanced. Typically cardiovascular toxicity was evident prior to lethality. Confocal microscopy revealed that PEI-MSNs penetrated into the embryos whereas PEG-, NH2- and SUCC-MSNs remained aggregated on the skin surface. Direct exposure of inner organs by microinjecting NH₂-MSNs and PEI-MSNs demonstrated that the particles displayed similar toxicity indicating that functionalization affects the toxicity profile by influencing penetrance through biological barriers. The data emphasize the need for careful analyses of toxicity mechanisms in relevant models and constitute an important knowledge step towards the development of safer and sustainable nanotherapies

Nanoparticle design considerations for molecular imaging of apoptosis: Diagnostic, prognostic, and therapeutic value

The present review analyzes various approaches for the design and synthesis of different nanoparticles for imaging and therapy. Nanoparticles for computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET) and optical imaging are discussed. The influence of nanoparticle size, shape, surface charge, composition, surface functionalization, active targeting and other factors on imaging and therapeutic efficacy is analyzed. Cyto- and genotoxicity of nanoparticles are also discussed. Special attention in the review is paid to the imaging of apoptotic tissues and cells in different diseases.

Bioapplications of renal-clearable luminescent metal nanoparticles

This review summarizes the recent synthetic strategies of the renal-clearable luminescent metal nanoparticles, and discusses the biological behaviors and current disease-related applications of this type of biomaterials in tumor targeting, kidney disease and antimicrobial investigations.

A physiologically based pharmacokinetic model to predict the superparamagnetic iron oxide nanoparticles (SPIONs) accumulation in vivo

Superparamagnetic iron oxide nanoparticles (SPIONs) have been identified as a promising material for biomedical applications. These include as contrast agents for medical imaging, drug delivery and/or cancer cell treatment. The nanotoxicological profile of SPIONs has been investigated in different studies and the distribution of SPIONs in the human body has not been fully characterized. The aim of this study was to develop a physiologically-based pharmacokinetic (PBPK) model to predict the pharmacokinetics of SPIONs. The distribution and accumulation of SPIONs in organs were simulated taking into consideration their penetration through capillary walls and their active uptake by specialized macrophages in the liver, spleen and lungs. To estimate the kinetics of SPION uptake, a novel experimental approach using primary macrophages was developed. The murine PBPK model was validated against in vivo pharmacokinetic data, and accurately described accumulation in liver, spleen and lungs. After validation of the murine model, a similar PBPK approach was developed to simulate the distribution of SPIONs in humans. These data demonstrate the utility of PBPK modeling for estimating biodistribution of inorganic nanoparticles and represents an initial platform to provide computational prediction of nanoparticle pharmacokinetics.

In Vitro Evaluation of the Biological Responses of Canine Macrophages Challenged with PLGA Nanoparticles Containing Monophosphoryl Lipid A

Poly (lactic-co-glycolic acid) nanoparticles (PLGA NPs) have been considerably studied as a promising biodegradable delivery system to induce effective immune responses and to improve stability, safety, and cost effectiveness of vaccines. The study aimed at evaluating early inflammatory effects and cellular safety of PLGA NPs, co-encapsulating ovalbumin (PLGA/OVA NPs), as a model antigen and the adjuvant monophosphoryl lipid A (PLGA/MPLA NPs) as an adjuvant, on primary canine macrophages. The PLGA NPs constructs were prepared following the emulsion-solvent evaporation technique and further physic-chemically characterized. Peripheral blood mononuclear cells were isolated from canine whole blood by magnetic sorting and further cultured to generate macrophages. The uptake of PLGA NP constructs by macrophages was demonstrated by flow cytometry, transmission electron microscopy and confocal microscopy. Macrophage viability and morphology were evaluated by trypan blue exclusion and light microscopy. Macrophages were immunophenotyped for the expression of MHC-I and MHC-II and gene expression of Interleukin-10 (IL-10), Interleukin-12 (IL-12p40), and tumor necrosis factor alpha (TNF-α) were measured. The results showed that incubation of PLGA NP constructs with macrophages revealed effective early uptake of the PLGA NPs without altering the viability of macrophages. PLGA/OVA/MPLA NPs strongly induced TNF-α and IL-12p40 expression by macrophages as well as increase relative expression of MHC-I but not MHC-II molecules. Taken together, these results indicated that PLGA NPs with addition of MPLA represent a good model, when used as antigen carrier, for further, in vivo, work aiming to evaluate their potential to induce strong, specific, immune responses in dogs.

Effects of surface charges of gold nanoclusters on long-term in vivo biodistribution, toxicity, and cancer radiation therapy

Gold nanoclusters (Au NCs) have exhibited great advantages in medical diagnostics and therapies due to their efficient renal clearance and high tumor uptake. The in vivo effects of the surface chemistry of Au NCs are important for the development of both nanobiological interfaces and potential clinical contrast reagents, but these properties are yet to be fully investigated. In this study, we prepared glutathione-protected Au NCs of a similar hydrodynamic size but with three different surface charges: positive, negative, and neutral. Their in vivo biodistribution, excretion, and toxicity were investigated over a 90-day period, and tumor uptake and potential application to radiation therapy were also evaluated. The results showed that the surface charge greatly influenced pharmacokinetics, particularly renal excretion and accumulation in kidney, liver, spleen, and testis. Negatively charged Au NCs displayed lower excretion and increased tumor uptake, indicating a potential for NC-based therapeutics, whereas positively charged clusters caused transient side effects on the peripheral blood system.