Serum-mediated recognition of liposomes by phagocytic cells of the reticuloendothelial system - The concept of tissue specificity

Elucidation of the Tissue Distribution and Host Immunostimulatory Activity of Exogenously Administered Probiotic-Derived Extracellular Vesicles for Immunoadjuvant

Extracellular vesicles (EVs) are cell-derived nanoparticles that can be used as novel biomaterials. In the development of EVs-based therapeutic systems, it is essential to understand the in vivo fate of exogenously administered EVs and subsequent biological responses mediated by EVs. Although probiotics and microorganisms that modulate the host immune system also secrete EVs, their tissue distribution and biological reactions after administration to the host have not been sufficiently elucidated. In this study, we characterized EVs released from the probiotics Bifidobacterium longum (B-EVs) and Lactobacillus plantarum WCFS1 (L-EVs) in terms of tissue distribution and immune-activating capacity after intravenous and subcutaneous administration in mice. B-EVs and L-EVs exhibited particle sizes of approximately 100-160 nm and negative zeta potentials. These EVs contained peptidoglycan, DNA, and RNA as their cargoes. Intravenously administered B-EVs and L-EVs mainly accumulated in the liver and spleen. Furthermore, liver F4/80 and splenic CD169 macrophages took up the intravenously administered EVs. Subcutaneously administered B-EVs and L-EVs accumulated in the lymph nodes and were mainly located in the B-lymphocyte zone, indicating that exogenously administered probiotic-derived EVs showed a similar biodistribution, irrespective of the EVs-secreting cell type. Evaluation of EVs-mediated immune reactions demonstrated that intravenously administered EVs showed little activation potency. In contrast, subcutaneously administered B-EVs strongly increased the expression of inflammatory cytokine (TNF-α) and co-stimulatory molecules (CD40 and CD80) than L-EVs. These findings indicate that the subcutaneous administration of B-EVs is a useful strategy for the development of novel EVs-based immunotherapies.

Supramolecular assemblies from antimony(V) complexes for the treatment of leishmaniasis

The pentavalent meglumine antimoniate (MA) is still a first-line drug in the treatment of leishmaniasis in several countries. As an attempt to elucidate its mechanism of action and develop new antimonial drugs with improved therapeutic profile, Sb(V) complexes with different ligands, including β-cyclodextrin (β-CD), nucleosides and non-ionic surfactants, have been studied. Interestingly, Sb(V) oxide, MA, its complex with β-CD, Sb(V)-guanosine complex and amphiphilic Sb(V) complexes with N-alkyl-N-methylglucamide, have shown marked tendency to self-assemble in aqueous solutions, forming nanoaggregates, hydrogel or micelle-like nanoparticles. Surprisingly, the resulting assemblies presented in most cases slow dissociation kinetics upon dilution and a strong influence of pH, which impacted on their pharmacokinetic and therapeutic properties against leishmaniasis. To explain this unique property, we raised the hypothesis that multiple pnictogen bonds could contribute to the formation of these assemblies and their kinetic of dissociation. The present article reviews our current knowledge on the structural organization and physicochemical characteristics of Sb-based supramolecular assemblies, as well as their pharmacological properties and potential for treatment of leishmaniasis. This review supports the feasibility of the rational design of new Sb(V) complexes with supramolecular assemblies for the safe and effective treatment of leishmaniasis.

The role of protein corona on nanodrugs for organ-targeting and its prospects of application

Nowadays, nanodrugs become a hotspot in the high-end medical field. They have the ability to deliver drugs to reach their destination more effectively due to their unique properties and flexible functionalization. However, the fate of nanodrugs in vivo is not the same as those presented in vitro, which indeed influenced their therapeutic efficacy in vivo. When entering the biological organism, nanodrugs will first come into contact with biological fluids and then be covered by some biomacromolecules, especially proteins. The proteins adsorbed on the surface of nanodrugs are known as protein corona (PC), which causes the loss of prospective organ-targeting abilities. Fortunately, the reasonable utilization of PC may determine the organ-targeting efficiency of systemically administered nanodrugs based on the diverse expression of receptors on cells in different organs. In addition, the nanodrugs for local administration targeting diverse lesion sites will also form unique PC, which plays an important role in the therapeutic effect of nanodrugs. This article introduced the formation of PC on the surface of nanodrugs and summarized the recent studies about the roles of diversified proteins adsorbed on nanodrugs and relevant protein for organ-targeting receptor through different administration pathways, which may deepen our understanding of the role that PC played on organ-targeting and improve the therapeutic efficacy of nanodrugs to promote their clinical translation.

Core polymer optimization of ternary siRNA nanoparticles enhances in vivo safety, pharmacokinetics, and tumor gene silencing

Gene silencing with siRNA nanoparticles (si-NPs) is promising but still clinically unrealized for inhibition of tumor driver genes. Ternary si-NPs containing siRNA, a single block NP core-forming polymer poly[(2-(dimethylamino)ethyl methacrylate)-co-(butyl methacrylate)] (DMAEMA-co-BMA, 50B), and an NP surface-forming diblock polymer 20 kDa poly(ethylene glycol)-block-50B (20kPEG-50B) have the potential to improve silencing activity in tumors due to the participation of both 50B and 20kPEG-50B in siRNA electrostatic loading and endosome disruptive activity. Functionally, single block 50B provides more potent endosomolytic activity, while 20kPEG-50B colloidally stabilizes the si-NPs. Here, we systematically explored the role of the molecular weight (MW) of the core polymer and of the core:surface polymer ratio on ternary si-NP performance. A library of ternary si-NPs was formulated with variation in the MW of the 50B polymer and in the ratio of the core and surface forming polymeric components. Increasing 50B core polymer MW and ratio improved si-NP in vitro gene silencing potency, endosome disruptive activity, and stability, but these features also correlated with cytotoxicity. Concomitant optimization of 50B size and ratio resulted in the identification of lead ternary si-NPs 50B4-DP100, 50B8-DP100, and 50B12-DP25, with potent activity and minimal toxicity. Following intravenous treatment in vivo, all lead si-NPs displayed negligible toxicological effects and enhanced pharmacokinetics and tumor gene silencing relative to more canonical binary si-NPs. Critically, a single 1 mg/kg intravenous injection of 50B8-DP100 si-NPs silenced the tumor driver gene Rictor at the protein level by 80% in an orthotopic breast tumor model. 50B8-DP100 si-NPs delivering siRictor were assessed for therapeutic efficacy in an orthotopic HCC70 mammary tumor model. This formulation significantly inhibited tumor growth compared to siControl-NP treatment. 50B8-DP100 si-NPs were also evaluated for safety and were well-tolerated following a multi-dose treatment scheme. This work provides new insight on ternary si-NP structure-function relationships and identifies core polymer optimization strategies that can yield safe si-NP formulations with potent oncogene silencing.

Poly (beta-amino ester) as an in vivo nanocarrier for therapeutic nucleic acids

Therapeutic nucleic acids are an emerging class of therapy for treating various diseases through immunomodulation, protein replacement, gene editing, and genetic engineering. However, they need a vector to effectively and safely reach the target cells. Most gene and cell therapies rely on ex vivo gene delivery, which is laborious, time-consuming, and costly; therefore, devising a systematic vector for effective and safe in vivo delivery of therapeutic nucleic acids is required to target the cells of interest in an efficient manner. Synthetic nanoparticle vector poly beta amino ester (PBAE), a class of degradable polymer, is a promising candidate for in vivo gene delivery. PBAE is considered the most potent in vivo vector due to its excellent transfection performance and biodegradability. PBAE nanoparticles showed tunable charge density, diverse structural characteristics, excellent encapsulation capacity, high stability, stimuli-responsive release, site-specific delivery, potent binding to nucleic acids, flexible binding ability to various conjugates, and effective endosomal escape. These unique properties of PBAE are an essential contribution to in vivo gene delivery. The current review discusses each of the components used for PBAE synthesis and the impact of various environmental and physicochemical factors of the body on PBAE nanocarrier.

Study of FA12 peptide-modified PEGylated liposomal doxorubicin (PLD) as an effective ligand to target Muc1 in mice bearing C26 colon carcinoma: in silico, in vitro, and in vivo study

OBJECTIVES

This study tried to achieve active targeting of Muc1 in cancer; the surface of PEGylated liposomal doxorubicin (PLD/Doxil®) was decorated with FA12 peptide.

METHODS

According to docking results, FA12 was selected for this study, among four different peptides. MD simulation was also conducted as an additional confirmation of the binding interaction between FA12 and Muc1. Liposomal formulations were prepared; ¹HNMR and HPLC techniques were used to verify peptide conjugation to DSPE-PEG2000-COOH. Afterward, DSPE-PEG2000-FA12 was post-inserted into the PLD at 50, 100, 200, and 400 peptides per liposome. The size, zeta potential, release profile, cytotoxicity (IC₅₀), and cell uptake (using fluorescence microscopy and flow cytometry) were evaluated. In vivo biodistribution and antitumor activities were studied on mice bearing C-26 colon carcinoma.

RESULTS

Cell uptake and cytotoxicity results revealed that PLD-100 (targeted PLD with 100 FA12 per liposome) could significantly enhance cellular binding. Furthermore, PLD-100 demonstrated higher antitumor efficacy, indicating more remarkable survival compared to PLD and other targeted PLDs. PLD-100 exhibited higher doxorubicin tumor accumulation compared to PLD.

CONCLUSIONS

FA12 peptide is a promising targeting ligand for PLD to treat cancers with a high level of Muc1 expression and merits further investigations.

Nanoassemblies from Amphiphilic Sb Complexes Target Infection Sites in Models of Visceral and Cutaneous Leishmaniases

This work aims to evaluate whether nanoassemblies (NanoSb) made from antimony(V) complexes with octanoyl-N-methylglucamide (SbL8) or decanoyl-N-methylglucamide (SbL10) would effectively target the infection sites in visceral and cutaneous leishmaniases (VL and CL). NanoSb were investigated regarding stability at different pHs, accumulation of Sb in the macrophage host cell and liver, and in vitro and in vivo activities in models of leishmaniasis. The kinetic stability assay showed that NanoSb are stable at neutral pH, but release incorporated lipophilic substance after conformational change in media that mimic the gastric fluid and the parasitophorous vacuole. NanoSb promoted greater accumulation of Sb in macrophages and in the liver of mice after parenteral administration, when compared to conventional antimonial Glucantime^®. SbL10 was much more active than Glucantime^® against intramacrophage Leishmania amastigotes and less cytotoxic than SbL8 against macrophages. The in vitro SbL10 activity was further enhanced with co-incorporated miltefosine. NanoSb showed high antileishmanial activity in the L. donovani murine VL after parenteral administration and moderate activity in the L. amazonensis murine CL after topical treatment. This study supports the ability of NanoSb to effectively deliver a combination of Sb and co-incorporated drug to host cell and infected tissues, in a better way than Glucantime^® does.

Why nanoparticles prefer liver macrophage cell uptake in vivo

Effective delivery of therapeutic and diagnostic nanoparticles is dependent on their ability to accumulate in diseased tissues. However, most nanoparticles end up in liver macrophages regardless of nanoparticle design after administration. In this review, we describe the interactions of liver macrophages with nanoparticles. Liver macrophages have significant advantages in interacting with circulating nanoparticles over most target cells and tissues in the body. We describe these advantages in this article. Understanding these advantages will enable the development of strategies to overcome liver macrophages and deliver nanoparticles to targeted diseased tissues effectively. Ultimately, these approaches will increase the therapeutic efficacy and diagnostic signal of nanoparticles.

Radiolabeled nanomaterials for biomedical applications: radiopharmacy in the era of nanotechnology

BACKGROUND

Recent advances in nanotechnology have offered new hope for cancer detection, prevention, and treatment. Nanomedicine, a term for the application of nanotechnology in medical and health fields, uses nanoparticles for several applications such as imaging, diagnostic, targeted cancer therapy, drug and gene delivery, tissue engineering, and theranostics.

RESULTS

Here, we overview the current state-of-the-art of radiolabeled nanoparticles for molecular imaging and radionuclide therapy. Nanostructured radiopharmaceuticals of technetium-99m, copper-64, lutetium-177, and radium-223 are discussed within the scope of this review article.

CONCLUSION

Nanoradiopharmaceuticals may lead to better development of theranostics inspired by ingenious delivery and imaging systems. Cancer nano-theranostics have the potential to lead the way to more specific and individualized cancer treatment.

Targeted co-delivery biomimetic nanoparticles reverse macrophage polarization for enhanced rheumatoid arthritis therapy

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease, which is characterized by synovial inflammation and autoimmunity. The main cause of the disease is the imbalance of the proportion of pro-inflammatory macrophages (M1-type) and anti-inflammatory macrophages (M2-type) in the synovial tissues of the joint. To restore this balance, in our study, the interleukin-10 encoding anti-inflammatory cytokines (IL-10 pDNA) and chemotherapeutic drug dexamethasone sodium phosphate (DSP) were co-loaded into human serum albumin (HSA) preparing pDNA/DSP-NPs to actively target macrophages in synovium tissue to promote M1-M2 polarization. Confocal laser scanning microscope and western blot were used to demonstrate the targeting ability of co-delivery nanoparticles. In vivo, the real-time fluorescence imaging system and HPLC were used to study the tissue distribution and pharmacokinetics of nanoparticles, and the results showed that the accumulation of nanoparticles in the inflammatory joint site was higher. Its pharmacodynamics were evaluated in collagen-induced arthritis (CIA) rat model, and it demonstrated that the pDNA/DSP-NPs significantly reduced the expression of serum inflammatory factors and alleviated joint swelling and bone erosion, suggesting the favorable therapeutic effect. The synergistic treatment effect of IL-10 pDNA and DSP in this system was achieved by reducing the secretion of pro-inflammatory factors (TNF-α, IL-1β) and increasing the expression of anti-inflammatory factors (IL-10) to promote the M1-M2 polarization of macrophages. Our strategy is promising for co-delivery of gene drugs and chemical drugs by biomimetic natural materials to promote macrophages polarization so that to achieve synergically treatment of inflammatory disease.

Review: Development of SARS-CoV-2 immuno-enhanced COVID-19 vaccines with nano-platform

Vaccination is the most effective way to prevent coronavirus disease 2019 (COVID-19). Vaccine development approaches consist of viral vector vaccines, DNA vaccine, RNA vaccine, live attenuated virus, and recombinant proteins, which elicit a specific immune response. The use of nanoparticles displaying antigen is one of the alternative approaches to conventional vaccines. This is due to the fact that nano-based vaccines are stable, able to target, form images, and offer an opportunity to enhance the immune responses. The diameters of ultrafine nanoparticles are in the range of 1-100 nm. The application of nanotechnology on vaccine design provides precise fabrication of nanomaterials with desirable properties and ability to eliminate undesirable features. To be successful, nanomaterials must be uptaken into the cell, especially into the target and able to modulate cellular functions at the subcellular levels. The advantages of nano-based vaccines are the ability to protect a cargo such as RNA, DNA, protein, or synthesis substance and have enhanced stability in a broad range of pH, ambient temperatures, and humidity for long-term storage. Moreover, nano-based vaccines can be engineered to overcome biological barriers such as nonspecific distribution in order to elicit functions in antigen presenting cells. In this review, we will summarize on the developing COVID-19 vaccine strategies and how the nanotechnology can enhance antigen presentation and strong immunogenicity using advanced technology in nanocarrier to deliver antigens. The discussion about their safe, effective, and affordable vaccines to immunize against COVID-19 will be highlighted.

Design and construction of IR780- and EGCG-based and mitochondrial targeting nanoparticles and their application in tumor chemo-phototherapy

An integration combination of phototherapy and chemotherapy to treat carcinoma, solving the inner limitation of individual-modal chemical agent-based therapy or phototherapy, emerges to be a strategy with high prospects for achieving synergistic curative effects. The dye IR780-iodide (IR780) close to infrared radiation is a phototherapy agent with high prospects. However, it is limited in its clinical applications due to poor solubility in water. While epigallocatechin-3-gallate (EGCG), naturally resourced green tea polyphenol, has been extensively proven with intrinsic antitumor activity, but it is largely restricted by its low bioavailability in vivo. Hence, novel multiple-function nanoparticles comprising hyaluronic acid (HA) and IR780 were proposed to deliver EGCG, defined as EGCG@THSI nano-scale particles (EGCG@THSI NPs), thereby rapidly solving limitations of EGCG and IR780. Amphiphilic nano-scale carrier was prepared by triphenylphosphine (TPP), hyaluronic acid (HA), cystamine, and IR780, termed as TPP-HA-SS-IR780, and EGCG was loaded into the amphiphilic copolymer by self-assembly. TPP-HA-SS-IR780 endowed the as-synthesized EGCG@THSI NPs with excellent TPP-mediated mitochondrial-targeted and glutathione-triggered rapid drug release properties. As impacted by the integration of phototherapy and chemotherapy, the EGCG@THSI NPs under NIR laser irradiation showed a prominent anti-tumor effect. Taken together, this study presented a multiple-function nano-scale carrier platform with high prospects in improving the therapeutic efficacy of anti-carcinoma drugs.

Targeted Delivery of Chloroquine to Antigen-Presenting Cells Enhances Inhibition of the Type I Interferon Response

Systemic lupus erythematosus (SLE) causes damaging inflammation in multiple organs via the accumulation of immune complexes. These complexes activate plasmacytoid dendritic cells (pDCs) via toll-like receptors (TLRs), contributing to disease pathogenesis by driving the secretion of inflammatory type I interferons (IFNs). Antimalarial drugs, such as chloroquine (CQ), are TLR antagonists used to alleviate inflammation in SLE. However, they require ∼3 months of continuous use before achieving therapeutic efficacy and can accumulate in the retinal pigment epithelium with chronic use, resulting in retinopathy. We hypothesized that poly(ethylene glycol)-b-poly(propylene sulfide) filamentous nanocarriers, filomicelles (FMs), could directly deliver CQ to pDCs via passive, morphology-based targeting to concentrate drug delivery to specific immune cells, improve drug activity by increased inhibition of type I IFN, and enhance efficacy per dose. Healthy human peripheral blood mononuclear cells were treated with soluble CQ or CQ-loaded FMs, stimulated with TLR agonists or SLE patient sera, and type I IFN secretion was quantified via multi-subtype IFN-α ELISA and MX1 gene expression using real-time reverse transcription-quantitative polymerase chain reaction. Our results showed that 50 μg CQ/mg FM decreased MX1 expression and IFN-α production after TLR activation with either synthetic nucleic acid agonists or immune complex-rich sera from SLE patients. Cellular uptake and biodistribution studies showed that FMs preferentially accumulate in human pDCs and monocytes in vitro and in tissues frequently damaged in SLE patients (i.e., kidneys), while sparing the eye in vivo. These results showed that nanocarrier morphology enables drug delivery, and CQ-FMs may be equally effective and more targeted than soluble CQ at inhibiting SLE-relevant pathways.

A NO-Responsive Ratiometric Fluorescent Nanoprobe for Monitoring Drug-Induced Liver Injury in the Second Near-Infrared Window

Currently, drug-induced liver injury (DILI) has become a huge concern for the majority of modern medicine, whereas the diagnosis of DILI is still in its infancy due to the lack of appropriate methods. Herein, based on the fact that nitric oxide (NO) has been recognized as an early unifying, direct, and vital biomarker for DILI, we rationally designed and developed a NO-responsive ratiometric fluorescent nanoprobe DCNP@MPS@IR NO to quantitatively detect NO and monitor DILI in the second near-infrared (NIR-II) window. In the presence of NO, due to the conversion of IR NO into IR RA and excellent stability of the downconversion nanoparticle (DCNP), DCNP@MPS@IR NO could present a "Turn-On" fluorescence signal at 1050 nm under 808 nm excitation (F_{1050 Em, 808 Ex}) and an "Always-On" fluorescence signal at 1550 nm under 980 nm excitation (F_{1550 Em, 980 Ex}), which led to a "Turn-On" ratiometric fluorescence signal F_{1050 Em, 808 Ex}/F_{1550 Em, 980 Ex}. DCNP@MPS@IR NO was then successfully applied in vitro to selectively detect NO, at a linear concentration range of 0-100 μM with a limit of detection of 0.61 μM. In vivo results revealed that DCNP@MPS@IR was available to quantify NO in acetaminophen (APAP)-induced liver injury, monitor DILI, and screen an antidote for APAP through NIR-II ratiometric fluorescence imaging. We envision that our nanoprobe DCNP@MPS@IR NO might become a really useful biotechnology tool for visualizing and early diagnosis of drug-induced liver injury and revealing the mechanism of drug hepatotoxicity in the clinic in the near future.

Polymer nano-systems for the encapsulation and delivery of active biomacromolecular therapeutic agents

Biomacromolecular therapeutic agents, particularly proteins, antigens, enzymes, and nucleic acids are emerging as powerful candidates for the treatment of various diseases and the development of the recent vaccine based on mRNA highlights the enormous potential of this class of drugs for future medical applications. However, biomacromolecular therapeutic agents present an enormous delivery challenge compared to traditional small molecules due to both a high molecular weight and a sensitive structure. Hence, the translation of their inherent pharmaceutical capacity into functional therapies is often hindered by the limited performance of conventional delivery vehicles. Polymer drug delivery systems are a modular solution able to address those issues. In this review, we discuss recent developments in the design of polymer delivery systems specifically tailored to the delivery challenges of biomacromolecular therapeutic agents. In the future, only in combination with a multifaceted and highly tunable delivery system, biomacromolecular therapeutic agents will realize their promising potential for the treatment of diseases and for the future of human health.

Corona protein impacts on alternating current biosusceptometry signal and circulation times of differently coated MnFe2O4 nanoparticles

Background: We evaluated the impacts of corona protein (CP) formation on the alternating current biosusceptometry (ACB) signal intensity and in vivo circulation times of three differently coated magnetic nanoparticles (MNP): bare, citrate-coated and bovine serum albumin-coated MNPs. Methods: We employed the ACB system, gel electrophoresis and mass spectrometry analysis. Results: Higher CP formation led to a greater reduction in the in vitro ACB signal intensity and circulation time. We found fewer proteins forming the CP for the bovine serum albumin-coated MNPs, which presented the highest circulation time in vivo among the MNPs studied. Conclusion: These data showed better biocompatibility, stability and magnetic signal uniformity in biological media for bovine serum albumin-coated MNPs than for citrate-coated MNPs and bare MNPs.

Comprehensively enhanced delivery cascade by transformable beaded nanofibrils for pancreatic cancer therapy

Facing the barriers in each step of the in vivo delivery cascade, the low drug delivery efficiency remains problematic in tumor therapy. Although recently the nanofibril drug delivery systems have shown improved circulation and accumulation compared with nanoparticles, the poor deep penetration and cellular internalization hinder their application, especially for pancreatic cancer with dense stroma. To comprehensively address the hurdles in the delivery cascade, a matrix metalloproteinase 2 (MMP-2) responsive transformable beaded nanofibril, which integrates the merits of nanofibril and small-sized nanoparticles, is established. The beaded nanofibril (GD@PPF) is prepared by conjugating gemcitabine-loaded small-sized nanoparticles (GD) with fibrous PEG-PCL (PPF) via GPLGVRG, a substrate peptide of MMP-2. GD@PPF escapes the clearance of the reticuloendothelial system (RES), prolongs the circulation time, and increases the selective accumulation in the tumor as fibrous micelles. Once accumulated in the tumor, small positively-charged GD is released from the beaded nanofibrils in response to MMP-2 overexpression in the stroma of pancreatic cancer, enabling permeation in the dense tumor matrix and cellular internalization, which makes up for the shortcomings of fibrous micelles. Furthermore, the remaining fibrous PPF surround the tumor tightly to impede the efflux of drugs, leading to improved retention. GD@PPF is biocompatible and exhibits excellent antitumor effect in Pan 02 subcutaneous tumor models. Therefore, the MMP-2 responsive transformable beaded nanofibril, which enhances the delivery efficiency in multiple stage of the delivery cascade, presents a promising strategy for pancreatic cancer therapy.

Nonspecific Binding-Fundamental Concepts and Consequences for Biosensing Applications

Nature achieves differentiation of specific and nonspecific binding in molecular interactions through precise control of biomolecules in space and time. Artificial systems such as biosensors that rely on distinguishing specific molecular binding events in a sea of nonspecific interactions have struggled to overcome this issue. Despite the numerous technological advancements in biosensor technologies, nonspecific binding has remained a critical bottleneck due to the lack of a fundamental understanding of the phenomenon. To date, the identity, cause, and influence of nonspecific binding remain topics of debate within the scientific community. In this review, we discuss the evolution of the concept of nonspecific binding over the past five decades based upon the thermodynamic, intermolecular, and structural perspectives to provide classification frameworks for biomolecular interactions. Further, we introduce various theoretical models that predict the expected behavior of biosensors in physiologically relevant environments to calculate the theoretical detection limit and to optimize sensor performance. We conclude by discussing existing practical approaches to tackle the nonspecific binding challenge in vitro for biosensing platforms and how we can both address and harness nonspecific interactions for in vivo systems.

A Novel Formulation of Cisplatin with γ-Polyglutamic Acid and Chitosan Reduces Its Adverse Renal Effects: An In Vitro and In Vivo Animal Study

Cisplatin (cis-diamminedichloroplatinum (II); CDDP) is a key chemotherapeutic agent but causes renal damage and other off-target effects. Here, we describe the pharmacological and biochemical characteristics of a novel formulation of CDDP complexed with γ-polyglutamic acid (γ-PGA) and chitosan (CS), γ-PGA/CDDP-CS, developed by complexing CDDP with γ-PGA, then adding CS (15 kDa; 10 mol%/γ-PGA). We analyzed tumor cytotoxicity in vitro, as well as blood kinetics, acute toxicity, and antitumor efficacy in vivo in BALB/cAJcl mice. γ-PGA/CDDP-CS showed pH-dependent release in vitro over 12 days (9.1% CDDP released at pH 7.4; 49.9% at pH 5.5). It showed in vitro cytotoxicity in a dose-dependent manner similar to that of uncomplexed CDDP. In a mesothelioma-bearing mouse model, a 15 mg/kg dose of CDDP inhibited tumor growth regardless of the type of formulation, complexed or uncomplexed; however, all mice in the uncomplexed CDDP group died within 13 days. γ-PGA/CDDP-CS was as effective as free CDDP in vivo but much less toxic.

Controlled Formation of a Protein Corona Composed of Denatured BSA on Upconversion Nanoparticles Improves Their Colloidal Stability

In the natural fluidic environment of a biological system, nanoparticles swiftly adsorb plasma proteins on their surface forming a “protein corona”, which profoundly and often adversely affects their residence in the systemic circulation in vivo and their interaction with cells in vitro. It has been recognized that preformation of a protein corona under controlled conditions ameliorates the protein corona effects, including colloidal stability in serum solutions. We report on the investigation of the stabilizing effects of a denatured bovine serum albumin (dBSA) protein corona formed on the surface of upconversion nanoparticles (UCNPs). UCNPs were chosen as a nanoparticle model due to their unique photoluminescent properties suitable for background-free biological imaging and sensing. UCNP surface was modified with nitrosonium tetrafluoroborate (NOBF₄) to render it hydrophilic. UCNP-NOBF₄ nanoparticles were incubated in dBSA solution to form a dBSA corona followed up by lyophilization. As produced dBSA-UCNP-NOBF₄ demonstrated high photoluminescence brightness, sustained colloidal stability after long-term storage and the reduced level of serum protein surface adsorption. These results show promise of dBSA-based nanoparticle pretreatment to improve the amiability to biological environments towards theranostic applications.

Complex Factors and Challenges that Affect the Pharmacology, Safety and Efficacy of Nanocarrier Drug Delivery Systems

Major developments in nanomedicines, such as nanoparticles (NPs), nanosomes, and conjugates, have revolutionized drug delivery capabilities over the past four decades. Although nanocarrier agents provide numerous advantages (e.g., greater solubility and duration of systemic exposure) compared to their small-molecule counterparts, there is considerable inter-patient variability seen in the systemic disposition, tumor delivery and overall pharmacological effects (i.e., anti-tumor efficacy and unwanted toxicity) of NP agents. This review aims to provide a summary of fundamental factors that affect the disposition of NPs in the treatment of cancer and why they should be evaluated during preclinical and clinical development. Furthermore, this chapter will highlight some of the translational challenges associated with elements of NPs and how these issues can only be addressed by detailed and novel pharmacology studies.

Preparation, Characterization, and In Vitro Pharmacodynamics and Pharmacokinetics Evaluation of PEGylated Urolithin A Liposomes

Urolithin A (Uro-A), a metabolite of ellagitannins in mammals' intestinal tract, displays broad biological properties in preclinical models, including anti-oxidant, anti-inflammatory, and anti-tumor effects. However, the clinical application of Uro-A is restricted because of its low aqueous solubility and short elimination half-life. Our purpose was to develop a delivery system to improve the bioavailability and anti-tumor efficacy of Uro-A. To achieve this goal, urolithin A-loaded PEGylated liposomes (Uro-A-PEG-LPs) were prepared for the first time and its physicochemical properties and anti-tumor efficacy in vitro were evaluated. The morphology of Uro-A-PEG-LPs displayed a uniform sphere under transmission electron microscope. The particle size, polydispersity index, zeta potential, and encapsulation efficiency of Uro-A-PEG-LPs were 122.8 ± 7.4 nm, 0.25 ± 0.16, - 25.5 ± 2.3 mV, and 94.6 ± 1.6%, respectively. Moreover, Uro-A-PEG-LPs possessed higher stability and could be stably stored at 4°C for a long time. In vitro release characteristics indicated that Uro-A-PEG-LPs possessed superior sustained release properties. The results of confocal laser scanning microscopy experiment showed that the coumarin 6-loaded PEGylated liposomes (C6-PEG-LPs) have superior cellular uptake than that of conventional liposomes. In addition, in vitro tests demonstrated that Uro-A-PEG-LPs elevated cytotoxicity and pro-apoptotic effect in human hepatoma cells comparing with free Uro-A. Furthermore, the results of pharmacokinetic experiments showed that the t_1/2, AUC_0-t, and MRT_0-t of Uro-A-PEG-LPs increased to 4.58-fold, 2.33-fold, and 2.43-fold than those of free Uro-A solution, respectively. Collectively, these manifested that PEGylated liposomes might be a potential delivery system for Uro-A to prolonging in vivo circulation time, promoting cellular uptake, and enhancing its anti-tumor efficacy.

Supramolecular self-assembled drug delivery system (SADDs) of vancomycin and tocopherol succinate as an antibacterial agent: in vitro, in silico and in vivo evaluations

In this study self-assembled drug delivery system (SADDs) composed of a hydrophobic d-α-tocopherol succinate (TS) and a hydrophilic vancomycin (VCM) were formulated, and its potential for enhancing the antibacterial activity of VCM against Staphylococcus aureus (SA) and Methicillin-resistant Staphylococcus aureus (MRSA) were explored. The SADDs were synthesized via supramolecular complexation, then characterized for in silico, in vitro and in vivo studies. In silico studies confirmed the self-assembly of VCM/TS into NPs. The size, surface charge and drug loading of the SADDs was ˂100 nm, -27 mV and 68%, respectively. The SADDs were non-hemolytic and biosafe. A sustained release of VCM from SADDs was noted, with 52.2% release after 48 hr. The in vitro antibacterial test showed a twofold decrease in Minimum inhibitory concentration (MIC) against SA and MRSA, and a significantly higher reduction in MRSA biofilms compared to bare VCM. Further, in silico studies confirmed strong and stable binding of TS to MRSA efflux pumps. The in vivo study using mice skin infection models showed a 9.5-fold reduction in bacterial load after treatment with SADDs, in comparison with bare VCM. These findings affirmed that VCM/TS NPs as a promising novel nano-delivery for treating bacterial infections.

Synthesis and in vivo evaluation of PEG-BP-BaYbF5 nanoparticles for computed tomography imaging and their toxicity

Computed tomography (CT) is one of the most widespread imaging techniques in clinical use worldwide. CT contrast agents are administered to improve soft tissue contrast and highlight blood vessels. However, the range of CT contrast agents available in the clinic is limited and they suffer from short-circulation times and low k-edge values that result in the need for high doses for in vivo applications. Nanomaterials containing a mixture of electron-dense elements, such as BaYbF₅ nanoparticles, have shown promise as more efficient CT contrast agents, but they require biocompatible coatings for biomedical applications. Here, we explore the use of a bifunctional PEG polymer (5 kDa) containing a terminal bisphosphonate (BP) anchor for efficient binding to the surface of BaYbF₅ nanomaterials. The resulting PEG(5)-BP-BaYbF₅ nanoparticles were synthesized and characterized using TEM, DLS, TGA, XRD and Z-potential measurements. Their in vitro stability was verified and their ability to produce CT contrast in a wide range of X-ray energies, covering preclinical and clinical scanners, was demonstrated. In vitro toxicity studies with PEG(5)-BP-BaYbF₅ in the phagocytic pro-monocytic human cell line U937 did not identify toxic effects, even at high concentrations (30 mM). In vivo, PEG(5)-BP-BaYbF₅ exhibited efficient CT contrast for angiography imaging, highlighting blood vessels and vascular organs, and long circulation times as expected from the PEG coating. However, at late time points (48 h), in vivo toxicity was observed. While the causes could not be completely elucidated, in vitro studies suggest that decomposition and release of Yb³⁺ and/or Ba²⁺ metal ions after decomposition of PEG(5)-BP-BaYbF₅ may play a role. Overall, despite the promising CT contrast properties, our results suggest that BaYbF₅ nanomaterials may suffer from significant long-term toxicities.

A Microfluidic Platform to design Multimodal PEG - crosslinked Hyaluronic Acid Nanoparticles (PEG-cHANPs) for diagnostic applications

The combination of different imaging modalities can allow obtaining simultaneously morphological and functional information providing a more accurate diagnosis. This advancement can be reached through the use of multimodal tracers, and nanotechnology-based solutions allow the simultaneous delivery of different diagnostic compounds moving a step towards their safe administration for multimodal imaging acquisition. Among different processes, nanoprecipitation is a consolidate method for the production of nanoparticles and its implementation in microfluidics can further improve the control over final product features accelerating its potential clinical translation. A Hydrodynamic Flow Focusing (HFF) approach is proposed to produce through a ONE-STEP process Multimodal Pegylated crosslinked Hyaluronic Acid NanoParticles (PEG-cHANPs). A monodisperse population of NPs with an average size of 140 nm is produced and Gd-DTPA and ATTO488 compounds are co-encapsulated, simultaneously. The results showed that the obtained multimodal nanoparticle could work as MRI/Optical imaging probe. Furthermore, under the Hydrodenticity effect, a boosting of the T1 values with respect to free Gd-DTPA is preserved.

Advances of Nano-Structured Extended-Release Local Anesthetics

Extended-release local anesthetics (LAs) have drawn increasing attention with their promising role in improving analgesia and reducing adverse events of LAs. Nano-structured carriers such as liposomes and polymersomes optimally meet the demands of/for extended-release, and have been utilized in drug delivery over decades and showed satisfactory results with extended-release. Based on mature technology of liposomes, EXPAREL, the first approved liposomal LA loaded with bupivacaine, has seen its success in an extended-release form. At the same time, polymersomes has advances over liposomes with complementary profiles, which inspires the emergence of hybrid carriers. This article summarized the recent research successes on nano-structured extended-release LAs, of which liposomal and polymeric are mainstream systems. Furthermore, with continual optimization, drug delivery systems carry properties beyond simple transportation, such as specificity and responsiveness. In the near future, we may achieve targeted delivery and controlled-release properties to satisfy various analgesic requirements.

Brome mosaic virus-like particles as siRNA nanocarriers for biomedical purposes

There is an increasing interest in the use of plant viruses as vehicles for anti-cancer therapy. In particular, the plant virus brome mosaic virus (BMV) and cowpea chlorotic mottle virus (CCMV) are novel potential nanocarriers for different therapies in nanomedicine. In this work, BMV and CCMV were loaded with a fluorophore and assayed on breast tumor cells. The viruses BMV and CCMV were internalized into breast tumor cells. Both viruses, BMV and CCMV, did not show cytotoxic effects on tumor cells in vitro. However, only BMV did not activate macrophages in vitro. This suggests that BMV is less immunogenic and may be a potential carrier for therapy delivery in tumor cells. Furthermore, BMV virus-like particles (VLPs) were efficiently loaded with small interfering RNA (siRNA) without packaging signal. The gene silencing was demonstrated by VLPs loaded with siGFP and tested on breast tumor cells that constitutively express the green fluorescent protein (GPF). After VLP-siGFP treatment, GFP expression was efficiently inhibited corroborating the cargo release inside tumor cells and the gene silencing. In addition, BMV VLP carring siAkt1 inhibited the tumor growth in mice. These results show the attractive potential of plant virus VLPs to deliver molecular therapy to tumor cells with low immunogenic response.

Immunomodulatory Nanosystems

Immunotherapy has emerged as an effective strategy for the prevention and treatment of a variety of diseases, including cancer, infectious diseases, inflammatory diseases, and autoimmune diseases. Immunomodulatory nanosystems can readily improve the therapeutic effects and simultaneously overcome many obstacles facing the treatment method, such as inadequate immune stimulation, off-target side effects, and bioactivity loss of immune agents during circulation. In recent years, researchers have continuously developed nanomaterials with new structures, properties, and functions. This Review provides the most recent advances of nanotechnology for immunostimulation and immunosuppression. In cancer immunotherapy, nanosystems play an essential role in immune cell activation and tumor microenvironment modulation, as well as combination with other antitumor approaches. In infectious diseases, many encouraging outcomes from using nanomaterial vaccines against viral and bacterial infections have been reported. In addition, nanoparticles also potentiate the effects of immunosuppressive immune cells for the treatment of inflammatory and autoimmune diseases. Finally, the challenges and prospects of applying nanotechnology to modulate immunotherapy are discussed.

Delivery of Local Anesthesia: Current Strategies, Safety, and Future Prospects

BACKGROUND

The systemic administration of anesthesia is associated with severe and undesirable side effects such as sedation, vomiting, nausea, allergies, respiratory problems, and neutrophil dysfunction. With the increase in the procedures of limb surgery, cosmetics, facial, skin, and cancer reconstruction, the demand for local anesthesia has increased multifold during the last one decade. Therefore, novel, safe, and cost-effective methods are being developed to deliver local anesthetics by the surgeons.

METHOD

To prepare a comprehensive research report on anesthesia, we performed a structured literature search of bibliographic databases for peer-reviewed articles published recently. The studies of different articles were summarized and a deductive qualitative and quantitative data analysis was applied. Subsequently, a comprehensive summary of the analysis was used to frame this review article with ample examples.

RESULTS

A thorough analysis of the reports suggested that there have been tremendous developments of synthesizing nanoparticle-based local anesthesia drugs. The active targeting ability of nanoparticle-based drug delivery strategy can further help to deliver the desired anesthetic drug locally. It was also found that different local anesthetic drugs are developed into liposome form and show better efficacy in patients receiving anesthesia.

CONCLUSION

The findings of this review article endorse that safe delivery of anesthesia drugs are essential for the safety of patients. Further, nanotechnology-based strategies are extremely useful for targeted delivery of anesthetic drugs at the required dose without affecting the neighboring tissues.

Role of Liposome Size, Surface Charge, and PEGylation on Rheumatoid Arthritis Targeting Therapy

Rheumatoid arthritis (RA) is a chronic, systemic, progressive autoimmune disease. The vascular permeability of inflamed joints in RA makes it a natural candidate for passive targeting, similar to the enhanced permeability and retention (EPR) effect in solid tumors. Thus, various therapeutic drugs have been encapsulated in nanocarriers to achieve longer in vivo circulation times and improve RA targeting. Although liposomes are the most widely used nanocarriers for RA treatment, the effects of physical and chemical characteristics of liposomes, such as particle sizes, surface charge, polyethylene glycol (PEG) chain length, and PEG concentration, on their passive RA targeting effect have not been fully elucidated. Here, we systematically investigated the effects of physical and chemical properties of liposomes on circulation time and conducted preliminary studies on their passive targeting mechanisms. A series of liposomes with different particle sizes (70, 100, 200, and 350 nm), surface charges (positive, negative, slight positive, and slight negative), PEG chain lengths (1, 2, and 5 kDa), and concentrations (5, 10, and 20% w/w of total lipid) were prepared by lipid film dispersion and extrusion. The pharmacokinetics of liposomes with different formulas were evaluated with a fluorescence microplate reader. A collagen-induced arthritis (CIA) mouse model was utilized to mimic RA pathological conditions and to evaluate the targeting and efficacy of liposomes with different properties using a near-infrared fluorescence imaging system. Uptake of fluorescent liposomes by various synovial cells was measured by flow cytometry. The results indicated that liposomes with 100 nm diameter, a slight negative charge, and 10% incorporation of 5 kDa PEG had better in vivo circulation time and inflamed joint targeting than did other liposomes. Dexamethasone (Dex) was encapsulated into optimized liposomes as an active ingredient for RA treatment. Pharmacodynamic studies demonstrated that Dex liposomes could significantly improve the antiarthritic efficacy of Dex in a CIA mouse model of RA. This study also found that the retention mechanism of RA was mainly increased because of the uptake of liposomes by fibroblasts and macrophages in inflamed joints. This study provides a persuasive explanation for passive RA targeting by liposomes and advances our ability to treat RA with nanomedicine.

Novel Gold Nanorod-Based HR1 Peptide Inhibitor for Middle East Respiratory Syndrome Coronavirus

Middle East respiratory syndrome coronavirus (MERS-CoV) causes a severe acute respiratory syndrome-like illness with high pathogenicity and mortality due to the lack of effective therapeutics. Currently, only few antiviral agents are available for the treatment of MERS, but their effects have been greatly impaired by low antiviral activity, poor metabolic stability, and serious adverse effects. Therefore, the development of effective treatment for MERS is urgently needed. In this study, a series of heptad repeat 1 (HR1) peptide inhibitors have been developed to inhibit HR1/HR2-mediated membrane fusion between MERS-CoV and host cells, which is the major pathway of MERS-CoV-induced host infections. Particularly, peptide pregnancy-induced hypertension (PIH) exhibits potent inhibitory activity with IC₅₀ of 1.171 μM, and its inhibitory effects can be further increased to 10-fold by forming a gold nanorod complex (PIH-AuNRs). In addition, PIH-AuNRs display enhanced metabolic stability and biocompatibility in vitro and in vivo and, therefore, effectively prevent MERS-CoV-associated membrane fusion. In summary, PIH-AuNRs represent a novel class of antiviral agents and have a great potential in treating MERS in the clinic.

Nanoparticle systems for cancer vaccine

As effective tools for public health, vaccines prevent disease by priming the body's adaptive and innate immune responses against an infection. Due to advances in understanding cancers and their relationship with the immune system, there is a growing interest in priming host immune defenses for a targeted and complete antitumor response. Nanoparticle systems have shown to be promising tools for effective antigen delivery as vaccines and/or for potentiating immune response as adjuvants. Here, we highlight relevant physiological processes involved in vaccine delivery, review recent advances in the use of nanoparticle systems for vaccines and discuss pertinent challenges to viably translate nanoparticle-based vaccines and adjuvants for public use.

Logical design and application of prodrug platforms

This review summarizes the current state of prodrugs and elaborates the logical design and future development of the prodrug platform.

Effective systemic siRNA delivery using dual-layer protected long-circulating nanohydrogel containing an inorganic core

PEG-dex-dopa nanohydrogel containing a CaP/siRNA core could achieve extended circulation with reduced RES accumulation, resulting in increased tumor accumulation.

Anti-EGFR lipid micellar nanoparticles co-encapsulating quantum dots and paclitaxel for tumor-targeted theranosis

Cancer theranosis is an emerging field of personalized medicine which enables individual anti-cancer treatment by monitoring the therapeutic responses of cancer patients. Based on a consideration of the nano-bio interactions related to the blood circulation of systemically administered nanoparticles in humans, as well as extravasation and active targeting, lipid micellar nanoparticles were co-loaded with paclitaxel (PTX) and quantum dots (QDs) to generate a theranostic delivery vehicle. To provide with a tumor-targeting capability, either an antibody or an aptamer against the epidermal growth factor receptor (EGFR) was conjugated to the micelle surface. The QD-containing micelles (QDMs), antibody-coupled QDMs (immuno-QDMs), and aptamer-coupled QDMs (aptamo-QDMs) were able to effectively circulate in blood for at least 8 h when administered intravenously into mice bearing EGFR-positive LS174T tumor xenografts. In vivo fluorescence imaging and a bio-distribution study showed that both the immuno-QDMs and aptamo-QDMs were largely localized in the tumor tissue. The tumor targeting capability enhanced the therapeutic efficacy of PTX for the target cancer cells. Both the immuno-PTX-QDMs and the aptamo-PTX-QDMs caused a stronger inhibition of LS174T tumor growth in mice, compared to the non-targeted PTX-QDMs. These results suggest that the anti-EGFR immuno-PTX-QDMs and anti-EGFR aptamo-PTX-QDMs could be utilized as a tumor-targeted theranostic delivery system for cancer treatment in the clinic.

Bioresorbable pressure sensors protected with thermally grown silicon dioxide for the monitoring of chronic diseases and healing processes

Pressures in the intracranial, intraocular and intravascular spaces are clinically useful for the diagnosis and management of traumatic brain injury, glaucoma and hypertension, respectively. Conventional devices for measuring these pressures require surgical extraction after a relevant operational time frame. Bioresorbable sensors, by contrast, eliminate this requirement, thereby minimizing the risk of infection, decreasing the costs of care and reducing distress and pain for the patient. However, the operational lifetimes of bioresorbable pressure sensors available at present fall short of many clinical needs. Here, we present materials, device structures and fabrication procedures for bioresorbable pressure sensors with lifetimes exceeding those of previous reports by at least tenfold. We demonstrate measurement accuracies that compare favourably to those of the most sophisticated clinical standards for non-resorbable devices by monitoring intracranial pressures in rats for 25 days. Assessments of the biodistribution of the constituent materials, complete blood counts, blood chemistry and magnetic resonance imaging compatibility confirm the biodegradability and clinical utility of the device. Our findings establish routes for the design and fabrication of bioresorbable pressure monitors that meet requirements for clinical use.

Carrier-Free, Pure Nanodrug Formed by the Self-Assembly of an Anticancer Drug for Cancer Immune Therapy

Ursolic acid (UA) is a food-plant-derived natural product which has good anticancer activities and low toxicity. However, the poor water solubility of UA limits its application in clinic. To address this issue, we developed a carrier-free nanodrug by self-assembly of UA. Here, we showed that UA nanoparticles (NPs) have a near-spherical shape with a diameter of ∼150 nm. UA NPs exhibited higher antiproliferative activity; significantly caused apoptosis; decreased the expression of COX-2/VEGFR2/VEGFA; and increased the immunostimulatory activity of TNF-α, IL-6, and IFN-β and decreased the activity of STAT-3 in A549 cells in vitro. Furthermore, UA NPs could inhibit tumor growth and have the ability of liver protection in vivo. More importantly, UA NPs could significantly improve the activation of CD4+ T-cells, which indicated that UA NPs have the potential for immunotherapy. Overall, a carrier-free UA nanodrug may be a promising drug to further enhance their anticancer efficacy and immune function.

Analysis of nanoparticle biomolecule complexes

Nanoparticles exposed to biological fluids adsorb biomolecules on their surface forming a biomolecular corona. This corona determines, on a molecular level, the interactions and impact the newly formed complex has on cells and organisms. The corona formation as well as the physiological and toxicological relevance are commonly investigated. However, an acknowledged but rarely addressed problem in many fields of nanobiotechnology is aggregation and broadened size distribution of nanoparticles following their interactions with the molecules of biological fluids. In blood serum, TiO₂ nanoparticles form complexes with a size distribution from 30 nm to more than 500 nm. In this study we have separated these complexes, with good resolution, using preparative centrifugation in a sucrose gradient. Two main apparent size populations were obtained, a fast sedimenting population of complexes that formed a pellet in the preparative centrifugation tube, and a slow sedimenting complex population still suspended in the gradient after centrifugation. Concentration and surface area dependent differences are found in the biomolecular corona between the slow and fast sedimenting fractions. There are more immunoglobulins, lipid binding proteins, and lipid-rich complexes at higher serum concentrations. Sedimentation rate and the biomolecular corona are important factors for evaluating any experiment including nanoparticle exposure. Our results show that traditional description of nanoparticles in biological fluids is an oversimplification and that more thorough characterisations are needed.

Magnetic resonance imaging quantification and biodistribution of magnetic nanoparticles using T1-enhanced contrast

Magnetic iron oxide nanoparticles have been used for various applications such as in the treatment of iron deficiency, as theranostic agents, and as drug carriers. The effective delivery of magnetic iron oxide nanoparticles into the lesion and iron quantification are vital for in vivo theranostic application. To determine the feasibility of using T₁ contrast to non-invasively quantify and monitor the IONPs in vivo, monodispersed Gd-doped iron oxide nanoparticles (GdIONPs) with 4 nm core size were fabricated and were used as T₁-weighted contrast agents to quantify iron contents based on MRI longitudinal relaxation times (T₁). Signal enhancement in positive T₁ contrast caused by GdIONPs was observed in this work. The in vivo T₁ relaxivity of GdIONPs in a tumor matched well with both in vitro T₁ relaxivity and ICP-MS results, demonstrating that the concentration of iron at the tumor site can be directly read from real-time in vivo MRI T₁ relaxivity. Hence, by using this strategy, the Fe content in the lesion can be accurately monitored based on MRI longitudinal relaxation times, and this may shed light on effective magnetic hyperthermia cancer therapy in future.

The Effects of Biological Fluids on Colloidal Stability and siRNA Delivery of a pH-Responsive Micellar Nanoparticle Delivery System

Nanoparticles (NPs) interact with complex protein milieus in biological fluids, and these interactions have profound effects on NP physicochemical properties and function. Surprisingly, most studies neglect the impact of these interactions, especially with respect to NP-mediated siRNA delivery. Here, the effects of serum on colloidal stability and siRNA delivery of a pH-responsive micellar NP delivery system were characterized. Results show cationic NP-siRNA complexes aggregate in ≥2% serum in buffer, but are stable in serum-free media. Furthermore, nonaggregated NP-siRNA delivered in serum-free media result in 4-fold greater siRNA uptake in vitro, compared to aggregated NP-siRNA. Interestingly, pH-responsive membrane lysis behavior, which is required for endosomal escape, and NP-siRNA dissociation, necessary for gene knockdown, are significantly reduced in serum. Consistent with these data, nonaggregated NP-siRNA in serum-free conditions result in highly efficient gene silencing, even at doses as low as 5 nM siRNA. NP-siRNA diameter was measured at albumin and IgG levels mimicking biological fluids. Neither albumin nor IgG alone induces NP-siRNA aggregation, implicating other serum proteins in NP colloidal instability. Finally, as a proof-of-principle that stability is maintained in established in vivo models, transmission electron microscopy reveals NP-siRNA are taken up by ductal epithelial cells in a nonaggregated state when injected retroductally into mouse salivary glands in vivo. Overall, this study shows serum-induced NP-siRNA aggregation significantly diminishes efficiency of siRNA delivery by reducing uptake, pH-responsive membrane lysis activity, and NP-siRNA dissociation. Moreover, these results highlight the importance of local NP-mediated drug delivery and are broadly applicable to other drug delivery systems.

Liposomal Irinotecan Accumulates in Metastatic Lesions, Crosses the Blood-Tumor Barrier (BTB), and Prolongs Survival in an Experimental Model of Brain Metastases of Triple Negative Breast Cancer

PURPOSE

The blood-tumor barrier (BTB) limits irinotecan distribution in tumors of the central nervous system. However, given that the BTB has increased passive permeability we hypothesize that liposomal irinotecan would improve local exposure of irinotecan and its active metabolite SN-38 in brain metastases relative to conventional irinotecan due to enhanced-permeation and retention (EPR) effect.

METHODS

Female nude mice were intracardially or intracranially implanted with human brain seeking breast cancer cells (brain metastases of breast cancer model). Mice were administered vehicle, non-liposomal irinotecan (50 mg/kg), liposomal irinotecan (10 mg/kg and 50 mg/kg) intravenously starting on day 21. Drug accumulation, tumor burden, and survival were evaluated.

RESULTS

Liposomal irinotecan showed prolonged plasma drug exposure with mean residence time (MRT) of 17.7 ± 3.8 h for SN-38, whereas MRT was 3.67 ± 1.2 for non-liposomal irinotecan. Further, liposomal irinotecan accumulated in metastatic lesions and demonstrated prolonged exposure of SN-38 compared to non-liposomal irinotecan. Liposomal irinotecan achieved AUC values of 6883 ± 4149 ng-h/g for SN-38, whereas non-liposomal irinotecan showed significantly lower AUC values of 982 ± 256 ng-h/g for SN-38. Median survival for liposomal irinotecan was 50 days, increased from 37 days (p<0.05) for vehicle.

CONCLUSIONS

Liposomal irinotecan accumulates in brain metastases, acts as depot for sustained release of irinotecan and SN-38, which results in prolonged survival in preclinical model of breast cancer brain metastasis.

Strategies for improving drug delivery: nanocarriers and microenvironmental priming

INTRODUCTION

The ultimate goal in the field of drug delivery is to exclusively direct therapeutic agents to pathological tissues in order to increase therapeutic efficacy and eliminate side effects. This goal is challenging due to multiple transport obstacles in the body. Strategies that improve drug transport exploit differences in the characteristics of normal and pathological tissues. Within the field of oncology, these concepts have laid the groundwork for a new discipline termed transport oncophysics. Areas covered: Efforts to improve drug biodistribution have mainly focused on nanocarriers that enable preferential accumulation of drugs in diseased tissues. A less common approach to enhance drug transport involves priming strategies that modulate the biological environment in ways that favor localized drug delivery. This review discusses a variety of priming and nanoparticle design strategies that have been used for drug delivery. Expert opinion: Combinations of priming agents and nanocarriers are likely to yield optimal drug distribution profiles. Although priming strategies have yet to be widely implemented, they represent promising solutions for overcoming biological transport barriers. In fact, such strategies are not restricted to priming the tumor microenvironment but can also be directed toward healthy tissue in order to reduce nanoparticle uptake.

Towards clinically translatable in vivo nanodiagnostics

Nanodiagnostics as a field makes use of fundamental advances in nanobiotechnology to diagnose, characterize and manage disease at the molecular scale. As these strategies move closer to routine clinical use, a proper understanding of different imaging modalities, relevant biological systems and physical properties governing nanoscale interactions is necessary to rationally engineer next-generation bionanomaterials. In this Review, we analyse the background physics of several clinically relevant imaging modalities and their associated sensitivity and specificity, provide an overview of the materials currently used for in vivo nanodiagnostics, and assess the progress made towards clinical translation. This work provides a framework for understanding both the impressive progress made thus far in the nanodiagnostics field as well as presenting challenges that must be overcome to obtain widespread clinical adoption.

The Impact of Protein Corona Formation on the Macrophage Cellular Uptake and Biodistribution of Spherical Nucleic Acids

The effect of serum protein adsorption on the biological fate of Spherical Nucleic Acids (SNAs) is investigated. Through a proteomic analysis, it is shown that G-quadruplexes templated on the surface of a gold nanoparticle in the form of SNAs mediate the formation of a protein corona that is rich in complement proteins relative to SNAs composed of poly-thymine (poly-T) DNA. Cellular uptake studies show that complement receptors on macrophage cells recognize the SNA protein corona, facilitating their internalization, and causing G-rich SNAs to accumulate in the liver and spleen more than poly-T SNAs in vivo. These results support the conclusion that nucleic acid sequence and architecture can mediate nanoparticle-biomolecule interactions and alter their cellular uptake and biodistribution properties and illustrate that nucleic acid sequence is an important parameter in the design of SNA therapeutics.

Human CD64-targeted non-viral siRNA delivery system for blood monocyte gene modulation

A subset of phagocytes including inflammatory monocytes in blood migrate and give rise to macrophages in inflammatory tissues which generated the idea that blood monocytes are the therapeutic targets for drug delivery. Fc gamma receptor I (CD64) is a membrane receptor for the Fc region of immunoglobulin G, primarily expressed on monocyte-lineage, and H22 a monoclonal antibody for human CD64 had shown rapid blood monocyte binding and occupation in clinical studies. Small interfering RNA-mediated gene silencing as a therapeutic has been proposed and is a promising strategy in terms of its "knock-down" ability on the target gene prior to translation. However, its instability and off-targeting effect must be overcome for success in clinical studies. In this study, we developed a non-viral delivery system composed of oligo-nona-arginine (9R) and anti-human CD64 single chain antibodies (H22) for human monocyte-specific siRNA delivery. A targeted and efficient siRNA delivery mediated by anti-CD64 scFv-9R was observed in CD64 positive human leukemia cells, THP-1. With primary human blood cells, anti-CD64 scFv-9R mediated gene silencing was quantitatively confirmed representing blood monocyte selective gene delivery. These results demonstrate the potential of anti-CD64 scFv-9R mediated siRNA delivery for the treatment of human inflammatory diseases via blood monocytes gene delivery.