Biodegradable nanoparticles for cytosolic delivery of therapeutics

Nanoparticle-Mediated Simultaneous Targeting of Mitochondrial Injury and Inflammation Attenuates Myocardial Ischemia-Reperfusion Injury

Background The opening of mitochondrial permeability transition pore and inflammation cooperatively progress myocardial ischemia-reperfusion (IR) injury, which hampers therapeutic effects of primary reperfusion therapy for acute myocardial infarction. We examined the therapeutic effects of nanoparticle-mediated medicine that simultaneously targets mitochondrial permeability transition pore and inflammation during IR injury. Methods and Results We used mice lacking cyclophilin D (CypD, a key molecule for mitochondrial permeability transition pore opening) and C-C chemokine receptor 2 and found that CypD contributes to the progression of myocardial IR injury at early time point (30-45 minutes) after reperfusion, whereas C-C chemokine receptor 2 contributes to IR injury at later time point (45-60 minutes) after reperfusion. Double deficiency of CypD and C-C chemokine receptor 2 enhanced cardioprotection compared with single deficiency regardless of the durations of ischemia. Deletion of C-C chemokine receptor 2, but not deletion of CypD, decreased the recruitment of Ly-6Chigh monocytes after myocardial IR injury. In CypD-knockout mice, administration of interleukin-1β blocking antibody reduced the recruitment of these monocytes. Combined administration of polymeric nanoparticles composed of poly-lactic/glycolic acid and encapsulating nanoparticles containing cyclosporine A or pitavastatin, which inhibit mitochondrial permeability transition pore opening and monocyte-mediated inflammation, respectively, augmented the cardioprotection as compared with single administration of nanoparticles containing cyclosporine A or pitavastatin after myocardial IR injury. Conclusions Nanoparticle-mediated simultaneous targeting of mitochondrial injury and inflammation could be a novel therapeutic strategy for the treatment of myocardial IR injury.

Hypoxia Engineered Bone Marrow Mesenchymal Stem Cells Targeting System with Tumor Microenvironment Regulation for Enhanced Chemotherapy of Breast Cancer

Improving the tumor targeting of docetaxel (DTX) would not only be favored for the chemotherapeutic efficacy, but also reduce its side effects. However, the regulation of the tumor microenvironment could further inhibit the growth of tumors. In this study, we introduced a system consisting of hypoxia-engineered bone marrow mesenchymal stem cells (H-bMSCs) and DTX micelles (DTX-M) for breast cancer treatment. First, the stem cell chemotherapy complex system (DTX@H-bMSCs) with tumor-targeting ability was constructed according to the uptake of DTX-M by hypoxia-induced bMSCs (H-bMSCs). DTX micellization improved the uptake efficiency of DTX by H-bMSCs, which equipped DTX@H-bMSCs with satisfactory drug loading and stability. Furthermore, the migration of DTX@H-bMSCs revealed that it could effectively target the tumor site and facilitate the drug transport between cells. Moreover, in vitro and in vivo pharmacodynamics of DTX@H-bMSCs exhibited a superior antitumor effect, which could promote the apoptosis of 4T1 cells and upregulate the expression of inflammatory factors at the tumor site. In brief, DTX@H-bMSCs enhanced the chemotherapeutic effect in breast cancer treatment.

PLGA-particle vaccine carrying TLR3/RIG-I ligand Riboxxim synergizes with immune checkpoint blockade for effective anti-cancer immunotherapy

With emerging supremacy, cancer immunotherapy has evolved as a promising therapeutic modality compared to conventional antitumor therapies. Cancer immunotherapy composed of biodegradable poly(lactic-co-glycolic acid) (PLGA) particles containing antigens and toll-like receptor ligands induces vigorous antitumor immune responses in vivo. Here, we demonstrate the supreme adjuvant effect of the recently developed and pharmaceutically defined double-stranded (ds)RNA adjuvant Riboxxim especially when incorporated into PLGA particles. Encapsulation of Riboxxim together with antigens potently activates murine and human dendritic cells, and elevated tumor-specific CD8+ T cell responses are superior to those obtained using classical dsRNA analogues. This PLGA particle vaccine affords primary tumor growth retardation, prevention of metastases, and prolonged survival in preclinical tumor models. Its advantageous therapeutic potency was further enhanced by immune checkpoint blockade that resulted in reinvigoration of cytotoxic T lymphocyte responses and tumor ablation. Thus, combining immune checkpoint blockade with immunotherapy based on Riboxxim-bearing PLGA particles strongly increases its efficacy.

Development and characterization of gel-in-water nanoemulsion as a novel drug delivery system

The effective delivery of anti-cancer drugs with minimal side effects and better therapeutic efficacy has remained an active area of research for many decades. Organogels have gained attention in recent years as potential drug delivery systems due to their high bioavailability, no first-pass metabolism and rapid action. Considering this, in the current study an organogel based nanoemulsion was developed aiming to effectively deliver hydrophobic drugs via encapsulation within in situ gellable organogel droplets, termed as gel-in-water (G/W) nanoemulsion. G/W nanoemulsion was prepared using a combination of lipiodol and organogelator 12-hydroxystearic acid (12-HSA) as inner gel phase; dispersed in water by ultrasonication and stabilized with polyoxyethylene hydrogenated castor oil (HCO-60) as a surfactant. The prepared nanoemulsion showed high drug loading efficiency (≈97%) with a mean diameter of 206 nm. Lower polydispersity index (PdI) value (≈0.1) suggests monodispersed nature of G/W nanoemulsion in the continuous phase. G/W nanoemulsion was found stable over six months in terms of particle size, zeta potential and pH at different storage temperatures. There was no cytotoxic effect of prepared G/W nanoemulsion on primary hepatocytes in vitro. In contrast, paclitaxel-loaded G/W showed a significant decrease in melanoma cell growth (*p < 0.05) both in vitro and in vivo. Our results support the hypothesis that organogel based nanoemulsions can be a promising drug delivery system.

Ultrasmall gold and silver/gold nanoparticles (2 nm) as autofluorescent labels for poly(D,L-lactide-co-glycolide) nanoparticles (140 nm)

Ultrasmall metallic nanoparticles show an efficient autofluorescence after excitation in the UV region, combined with a low degree of fluorescent bleaching. Thus, they can be used as fluorescent labels for polymer nanoparticles which are frequently used for drug delivery. A versatile water-in-oil-in-water emulsion-evaporation method was developed to load poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles with autofluorescent ultrasmall gold and silver/gold nanoparticles (diameter 2 nm). The metallic nanoparticles were prepared by reduction of tetrachloroauric acid with sodium borohydride and colloidally stabilised with 11-mercaptoundecanoic acid. They were characterised by UV-Vis and fluorescence spectroscopy, showing a large Stokes shift of about 370 nm with excitation maxima at 250/270 nm and emission maxima at 620/640 nm for gold and silver/gold nanoparticles, respectively. The labelled PLGA nanoparticles (140 nm) were characterised by dynamic light scattering (DLS), scanning electron microscopy (SEM), and UV-Vis and fluorescence spectroscopy. Their uptake by HeLa cells was followed by confocal laser scanning microscopy. The metallic nanoparticles remained inside the PLGA particle after cellular uptake, demonstrating the efficient encapsulation and the applicability to label the polymer nanoparticle. In terms of fluorescence, the metallic nanoparticles were comparable to fluorescein isothiocyanate (FITC).

Integrated System for Purification and Assembly of PCV Cap Nano Vaccine Based on Targeting Peptide Ligand

Purpose

The vaccine design has shifted from attenuated or inactivated whole pathogen vaccines to more pure and defined subunit vaccines. The purification of antigen proteins, especially the precise display of antigen regions, has become a key step affecting the effectiveness of subunit vaccines.

Materials and Methods

This work presents the application of molecular docking for a peptide ligand designed for PCV2 Cap purification and assembly in one step. Based on the PCV2 Cap protein affinity peptide (L11-DYWWQSWE), the amino terminal of PCV2 Cap was covalently coupled with the polylactic acid–glycolic acid copolymer (PLGA) carboxyl terminal through the EDC/NHS method.

Results

The PLGA had an average diameter of 106 nm. The average diameter increased to 122 nm after the PCV2 Cap protein conjugation, and the Zeta potential shifted from −13.7 mV to −9.6 mV, indicating that the PCV2 Cap protein stably binds to the PLGA. Compared with the free PCV2 Cap protein group, the neutralizing antibody titer was significantly increased on the 14th day after the PLGA-Cap immunization (P < 0.05). The neutralizing antibody level was extremely significant on the 28th day (P < 0.001). The CCK-8 analysis showed that PLGA-Cap had an obvious cytotoxic effect on RAW264.7 cells at the PLGA nanoparticle concentration up to 200 μg/mL but had no obvious cytotoxic effect on DC2.4 cells. Compared with the Cap protein group, the antigen-presenting cells had a stronger antigen uptake capacity and a higher fluorescence in the PLGA-Cap group. The immune effect showed that the level of the neutralizing antibody produced by this structure is much better than that of purified protein and helps improve the immune system response.

Conclusion

This technology provides a potential new perspective for the rapid enrichment of the antigen protein with the affinity peptide ligand.

Synthesis and Biological Application of Polylactic Acid

Over the past few decades, with the development of science and technology, the field of biomedicine has rapidly developed, especially with respect to biomedical materials. Low toxicity and good biocompatibility have always been key targets in the development and application of biomedical materials. As a degradable and environmentally friendly polymer, polylactic acid, also known as polylactide, is favored by researchers and has been used as a commercial material in various studies. Lactic acid, as a synthetic raw material of polylactic acid, can only be obtained by sugar fermentation. Good biocompatibility and biodegradability have led it to be approved by the U.S. Food and Drug Administration (FDA) as a biomedical material. Polylactic acid has good physical properties, and its modification can optimize its properties to a certain extent. Polylactic acid blocks and blends play significant roles in drug delivery, implants, and tissue engineering to great effect. This article describes the synthesis of polylactic acid (PLA) and its raw materials, physical properties, degradation, modification, and applications in the field of biomedicine. It aims to contribute to the important knowledge and development of PLA in biomedical applications.

Dithiolane-Crosslinked Poly(ε-caprolactone)-Based Micelles: Impact of Monomer Sequence, Nature of Monomer, and Reducing Agent on the Dynamic Crosslinking Properties

Dithiolanes are used to obtain dynamic and reversible crosslinks between polymer chains. Copolymers of two different dithiolane-containing cyclic carbonate monomers and ε-caprolactone (CL) were synthesized by ring-opening polymerization using a methoxy-poly(ethylene glycol) (mPEG) initiator and different catalysts (diphenyl phosphate (DPP), methanesulfonic acid (MSA), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), or Sn(Oct)2). Each catalyst required a different temperature, which had a pronounced influence on the reactivity ratio of the monomers and occurrence of transesterification reactions and, therefore, the monomer sequence. Self-crosslinkable copolymers were obtained when the dithiolane units were connected closely to the polymer backbone, whereas the presence of a linker unit between the dithiolane and the backbone prevented self-crosslinking. The former amphiphilic PEGylated block copolymers formed micelles by nanoprecipitation in the aqueous environment and crosslinked spontaneously by disulfide exchange during subsequent dialysis. These dithiolane-crosslinked micelles showed reduction-responsive dissociation in the presence of 10 mM glutathione, making them promising drug delivery systems for the intracellularly triggered cargo release.

Modulating chitosan-PLGA nanoparticle properties to design a co-delivery platform for glioblastoma therapy intended for nose-to-brain route

Nose-to-brain delivery is a promising approach to target drugs into the brain, avoiding the blood-brain barrier and other drawbacks related to systemic absorption, and enabling an effective and safer treatment of diseases such as glioblastoma (GBM). Innovative materials and technologies that improve residence time in the nasal cavity and modulate biological interactions represent a great advance in this field. Mucoadhesive nanoparticles (NPs) based on poly(lactic-co-glycolic acid) (PLGA) and oligomeric chitosan (OCS) were designed as a rational strategy and potential platform to co-deliver alpha-cyano-4-hydroxycinnamic acid (CHC) and the monoclonal antibody cetuximab (CTX) into the brain, by nasal administration. The influence of formulation and process variables (O/Aq volume ratio, Pluronic concentration, PLGA concentration, and sonication time) on the properties of CHC-loaded NPs (size, zeta potential, PDI and entrapment efficiency) was investigated by a two-level full factorial design (2⁴). Round, stable nano-sized particles (213-875 nm) with high positive surface charge (+ 33.2 to + 58.9 mV) and entrapment efficiency (75.69 to 93.23%) were produced by the emulsification/evaporation technique. Optimal process conditions were rationally selected based on a set of critical NP attributes (258 nm, + 37 mV, and 88% EE) for further conjugation with CTX. The high cytotoxicity of CHC-loaded NPs and conjugated NPs was evidenced for different glioma cell lines (U251 and SW1088). A chicken chorioallantoic membrane assay highlighted the expressive antiangiogenic activity of CHC-loaded NPs, which was enhanced for conjugated NPs. The findings of this work demonstrated the potential of this nanostructured polymeric platform to become a novel therapeutic alternative for GBM treatment. Graphical abstract.

Optimized Polyethylene Glycolylated Polymer-Lipid Hybrid Nanoparticles as a Potential Breast Cancer Treatment

Purpose: The aim of this work is to optimize a polyethylene glycolated (PEGylated) polymer–lipid hybrid nanoparticulate system for the delivery of anastrozole (ANS) to enhance its biopharmaceutical attributes and overall efficacy. Methods: ANS loaded PEGylated polymer–lipid hybrid nanoparticles (PLNPs) were prepared by a direct emulsification solvent evaporation method. The physical incorporation of PEG was optimized using variable ratios. The produced particles were evaluated to discern their particle size and shape, zeta-potential, entrapment efficiency, and physical stability. The drug-release profiles were studied, and the kinetic model was analyzed. The anticancer activity of the ANS PLNPs on estrogen-positive breast cancer cell lines was determined using flow cytometry. Results: The prepared ANS-PLNPs showed particle sizes in the range of 193.6 ± 2.9 to 218.2 ± 1.9 nm, with good particle size uniformity (i.e., poly-dispersity index of around 0.1). Furthermore, they exhibited relatively low zeta-potential values ranging from −0.50 ± 0.52 to 6.01 ± 4.74. The transmission electron microscopy images showed spherical shape of ANS-PLNPs and the compliance with the sizes were revealed by light scattering. The differential scanning calorimetry DSC patterns of the ANS PLNPs revealed a disappearance of the characteristic sharp melting peak of pure ANS, supporting the incorporation of the drug into the polymeric matrices of the nanoparticles. Flow cytometry showed the apoptosis of MCF-7 cell lines in the presence of ANS-PLNPs. Conclusion: PEGylated polymeric nanoparticles presented a stable encapsulated system with which to incorporate an anticancer drug (ANS) with a high percentage of entrapment efficiency (around 80%), good size uniformity, and induction of apoptosis in MCF-7 cells.

Engineering Circulating Tumor Cells as Novel Cancer Theranostics

New ways to target and treat metastatic disease are urgently needed. Tumor “self-homing” describes the recruitment of circulating tumor cells (CTCs) back to a previously excised primary tumor location, contributing to tumor recurrence, as well as their migration to established metastatic lesions. Recently, self-homing CTCs have been exploited as delivery vehicles for anti-cancer therapeutics in preclinical primary tumor models. However, the ability of CTCs to self-home and treat metastatic disease is largely unknown.

Methods: Here, we used bioluminescence imaging (BLI) to explore whether systemically administered CTCs home to metastatic lesions and if CTCs armed with both a reporter gene and a cytotoxic prodrug gene therapy can be used to visualize and treat metastatic disease.

Results: BLI performed over time revealed a remarkable ability of CTCs to home to and treat tumors throughout the body. Excitingly, metastatic tumor burden in mice that received therapeutic CTCs was lower compared to mice receiving control CTCs.

Conclusion: This study demonstrates the noteworthy ability of experimental CTCs to home to disseminated breast cancer lesions. Moreover, by incorporating a prodrug gene therapy system into our self-homing CTCs, we show exciting progress towards effective and targeted delivery of gene-based therapeutics to treat both primary and metastatic lesions.

Influence of cholesterol on electroporation in lipid membranes of giant vesicles

Irreversible electroporation (IRE) is primarily a nonthermal ablative technology that uses a series of high-voltage and ultra-short pulses with high-frequency electrical energy to induce cell death. This paper presents the influence of cholesterol on the IRE-induced probability of pore formation and the rate constant of pore formation in giant unilamellar vesicles (GUVs). The GUVs are prepared by a mixture of dioleoylphosphatidylglycerol (DOPG), dioleoylphosphatidylcholine (DOPC) and cholesterol using the natural swelling method. An IRE signal of frequency 1.1 kHz is applied to the membranes of GUVs. The probability of pore formation and the rate constant of pore formation events are obtained using statistical analysis from several single GUVs. The time-dependent fraction of intact GUVs among all those examined is fitted to a single exponential decay function from where the rate constant of pore formation is calculated. The probability of pore formation and the rate constant of pore formation decreases with an increase in cholesterol content in the membranes of GUVs. Theoretical equations are fitted to the tension-dependent rate constant of pore formation and to the probability of pore formation, which allows us to obtain the line tension of membranes. The obtained line tension increases with an increase in cholesterol in the membranes. The increase in the energy barrier of the prepore state, due to the increase of cholesterol in membranes, is the main factor explaining the decrease in the rate constant of pore formation.

Cordycepin Nanoencapsulated in Poly(Lactic-Co-Glycolic Acid) Exhibits Better Cytotoxicity and Lower Hemotoxicity Than Free Drug

Purpose

Cordycepin, a natural product isolated from the fungus Cordyceps militaris, is a potential candidate for breast cancer therapy. However, due to its structural similarity with adenosine, cordycepin is rapidly metabolized into an inactive form in the body, hindering its development as a therapeutic agent. In the present study, we have prepared cordycepin as nanoparticles in poly(lactic-co-glycolic acid) (PLGA) and compared their cellular uptake, cytotoxicity and hemolytic potential with free cordycepin.

Materials and Methods

Cordycepin-loaded PLGA nanoparticles (CPNPs) were prepared by the double-emulsion solvent evaporation method. Physico-chemical characterization of the nanoparticles was done by zetasizer, transmission electron microscopy (TEM) and reverse-phase high-pressure liquid chromatography (RP-HPLC) analyses. Cellular uptake and cytotoxicity of CPNPs and free drug were tested in human breast cancer cells (MCF7). Hemolytic potential of both of these forms was evaluated in rat red blood cells (RBCs).

Results

Physico-chemical characterization revealed that CPNPs were spherical in shape, possessed a size range of 179–246 nm, and released the encapsulated drug sustainably over a period of 10 days. CPNPs exhibited a high level of cellular uptake and cytotoxicity than the free drug in MCF-7 cells. While CPNPs were not toxic to rat RBCs even at high concentrations, free cordycepin induced hemolysis of these cells at relatively low concentration.

Conclusion

Our results reveal that delivery as CPNPs could enhance the clinical efficacy of cordycepin substantially.

Cisplatin and farnesol co-encapsulated PLGA nano-particles demonstrate enhanced anti-cancer potential against hepatocellular carcinoma cells in vitro

Cisplatin (CDDP) is a potent chemotherapeutic drug, but its severe side-effects often prohibit its use. Combined treatment with CDDP plus Farnesol (FAR) and their co-encapsulated nano form were investigated in in vitro to examine if synergistic cytotoxicity of this combination could reduce unwanted side-effects of CDDP chemotherapy and potentiate CDDP anticancer activity against hepatocellular carcinoma (HCC) cells. After finding combination therapy of CDDP and FAR successfully combat HCC we formulated co-encapsulation of CDDP and FAR within poly(lactic-co-glycolic acid) copolymer (NCDDPFAR) by following the standardized solvent displacement method. NCDDPFAR treatment caused faster drug mobility, sustained particle release, site-specific action and higher percentage of apoptotic death compared with single drug treatment even at relatively low concentrations. Co-encapsulation of two drugs exhibited additive effects against HCC; FAR reduced CDDP-induced glutathione level by increasing expression of CYP2E1 while CDDP directly interacted with DNA; FAR up-regulated the expression of TopII, thereby promoting DNA breaks and escaping DNA repair machinery. Expression pattern of apoptotic genes like p53, Bax, cytochrome c and caspase-3 suggested that NCDDPFAR induced HCC cell death through mitochondrial intrinsic pathway. Administration of NCDDPFAR had better ability of drug carriage and enhanced anticancer potentials against HCC cells.

Multifunctional Nanoparticles in Precise Cancer Treatment: Considerations in Design and Functionalization of Nanocarriers

Nanotechnology has revolutionized cancer treatment in both diagnosis and therapy. Since the initial application of nanoparticles (NPs) in cancer treatment, the main objective of nanotechnology was developing effective nanosystems with high selectivity and specificity for cancer treatment and diagnosis. To achieve this, different encapsulation and conjugation strategies along with surface functionalization techniques have been developed to synthesize anticancer drugs loaded NPs with effective targeting to specific tumor cells. The unique physicochemical attributes of NPs make them promising candidates for targeted drug delivery, localized therapies, sensing, and targeting at cellular levels. However, a nanosystem for localized and targeted cancer managements should overcome several biological barriers and biomedical challenges such as endothelial barriers, blood brain barrier, reticuloendothelial system, selective targeting, biocompatibility, acute/chronic toxicity, tumor-targeting efficacy. The NPs for in vivo applications encounter barriers at system, organ, and the cellular level. To overcome these barriers, different strategies during the synthesis and functionalization of NPs should be adapted. Pharmacokinetics and cellular uptake of NPs are largely associated with physicochemical attributes of NPs, morphology, hydrodynamic size, charge, and other surface properties. These properties can be adjusted during different phases of synthesis and functionalization of the NPs. This study reviews the advances in targeted cancer treatment and the parameters influencing the efficacies of NPs as therapeutics. Different strategies for overcoming the biological barriers at cellular, organ and system levels and biomedical challenges are discussed. Moreover, the applications of NPs in preclinical and clinical practice are reviewed.

Glyco-nanoparticles: New drug delivery systems in cancer therapy

Cancer is known as one of the most common diseases that are associated with high mobility and mortality in the world. Despite several efforts, current cancer treatment modalities often are highly toxic and lack efficacy and specificity. However, the application of nanotechnology has led to the development of effective nanosized drug delivery systems which are highly selective for tumors and allow a slow release of active anticancer agents. Different Nanoparticles (NPs) such as the silicon-based nano-materials, polymers, liposomes and metal NPs have been designed to deliver anti-cancer drugs to tumor sites. Among different drug delivery systems, carbohydrate-functionalized nanomaterials, specially based on their multi-valent binding capacities and desirable bio-compatibility, have attracted considerable attention as an excellent candidate for controlled release of therapeutic agents. In addition, these carbohydrate functionalized nano-carriers are more compatible with construction of the intracellular delivery platforms like the carbohydrate-modified metal NPs, quantum dots, and magnetic nano-materials. In this review, we discuss recent research in the field of multifunctional glycol-nanoparticles (GNPs) intended for cancer drug delivery applications.

Sugar and Polymer Excipients Enhance Uptake and Splice-Switching Activity of Peptide-Dendrimer/Lipid/Oligonucleotide Formulations

Non-viral transfection vectors are commonly used for oligonucleotide (ON) delivery but face many challenges before reaching the desired compartments inside cells. With the support of additional compounds, it might be more feasible for a vector to endure the barriers and achieve efficient delivery. In this report, we screened 18 different excipients and evaluated their effect on the performance of peptide dendrimer/lipid vector to deliver single-stranded, splice-switching ONs under serum conditions. Transfection efficiency was monitored in four different reporter cell lines by measuring splice-switching activity on RNA and protein levels. All reporter cell lines used had a mutated human β-globin intron 2 sequence interrupting the luciferase gene, which led to an aberrant splicing of luciferase pre-mRNA and subsidence of luciferase protein translation. In the HeLa Luc/705 reporter cell line (a cervical cancer cell line), the lead excipients (Polyvinyl derivatives) potentiated the splice-switching activity up to 95-fold, compared to untreated cells with no detected cytotoxicity. Physical characterization revealed that lead excipients decreased the particle size and the zeta potential of the formulations. In vivo biodistribution studies emphasized the influence of formulations as well as the type of excipients on biodistribution profiles of the ON. Subsequently, we suggest that the highlighted impact of tested excipients would potentially assist in formulation development to deliver ON therapeutics in pre-clinical and clinical settings.

Recent Advances in Nanoencapsulation Systems Using PLGA of Bioactive Phenolics for Protection against Chronic Diseases

Plant-derived polyphenolic compounds have gained widespread recognition as remarkable nutraceuticals for the prevention and treatment of various disorders, such as cardiovascular, neurodegenerative, diabetes, osteoporosis, and neoplastic diseases. Evidence from the epidemiological studies has suggested the association between long-term consumption of diets rich in polyphenols and protection against chronic diseases. Nevertheless, the applications of these phytochemicals are limited due to its low solubility, low bioavailability, instability, and degradability by in vivo and in vitro conditions. Therefore, in recent years, newer approaches have been attempted to solve the restrictions related to their delivery system. Nanoencapsulation of phenolic compounds with biopolymeric nanoparticles could be a promising strategy for protection and effective delivery of phenolics. Poly(lactic-co-glycolic acid) (PLGA) is one of the most successfully developed biodegradable polymers that has attracted considerable attention due to its attractive properties. In this review, our main goal is to cover the relevant recent studies that explore the pharmaceutical significance and therapeutic superiority of the advance delivery systems of phenolic compounds using PLGA-based nanoparticles. A summary of the recent studies implementing encapsulation techniques applied to polyphenolic compounds from plants confirmed that nanoencapsulation with PLGA nanoparticles is a promising approach to potentialize their therapeutic activity.

Cancer Cell Membrane-Coated Nanoparticles for Cancer Management

Cancer is a global health problem in need of transformative treatment solutions for improved patient outcomes. Many conventional treatments prove ineffective and produce undesirable side effects because they are incapable of targeting only cancer cells within tumors and metastases post administration. There is a desperate need for targeted therapies that can maximize treatment success and minimize toxicity. Nanoparticles (NPs) with tunable physicochemical properties have potential to meet the need for high precision cancer therapies. At the forefront of nanomedicine is biomimetic nanotechnology, which hides NPs from the immune system and provides superior targeting capabilities by cloaking NPs in cell-derived membranes. Cancer cell membranes expressing "markers of self" and "self-recognition molecules" can be removed from cancer cells and wrapped around a variety of NPs, providing homotypic targeting and circumventing the challenge of synthetically replicating natural cell surfaces. Compared to unwrapped NPs, cancer cell membrane-wrapped NPs (CCNPs) provide reduced accumulation in healthy tissues and higher accumulation in tumors and metastases. The unique biointerfacing capabilities of CCNPs enable their use as targeted nanovehicles for enhanced drug delivery, localized phototherapy, intensified imaging, or more potent immunotherapy. This review summarizes the state-of-the-art in CCNP technology and provides insight to the path forward for clinical implementation.

Recent Advances in the Use of Focused Ultrasound for Magnetic Resonance Image-Guided Therapeutic Nanoparticle Delivery to the Central Nervous System

Targeting systemically-administered drugs and genes to specific regions of the central nervous system (CNS) remains a challenge. With applications extending into numerous disorders and cancers, there is an obvious need for approaches that facilitate the delivery of therapeutics across the impervious blood-brain barrier (BBB). Focused ultrasound (FUS) is an emerging treatment method that leverages acoustic energy to oscillate simultaneously administered contrast agent microbubbles. This FUS-mediated technique temporarily disrupts the BBB, allowing ordinarily impenetrable agents to diffuse and/or convect into the CNS. Under magnetic resonance image guidance, FUS and microbubbles enable regional targeting-limiting the large, and potentially toxic, dosage that is often characteristic of systemically-administered therapies. Subsequent to delivery across the BBB, therapeutics face yet another challenge: penetrating the electrostatically-charged, mesh-like brain parenchyma. Non-bioadhesive, encapsulated nanoparticles can help overcome this additional barrier to promote widespread treatment in selected target areas. Furthermore, nanoparticles offer significant advantages over conventional systemically-administered therapeutics. Surface modifications of nanoparticles can be engineered to enhance targeted cellular uptake, and nanoparticle formulations can be tailored to control many pharmacokinetic properties such as rate of drug liberation, distribution, and excretion. For instance, nanoparticles loaded with gene plasmids foster relatively stable transfection, thus obviating the need for multiple, successive treatments. As the formulations and applications of these nanoparticles can vary greatly, this review article provides an overview of FUS coupled with polymeric or lipid-based nanoparticles currently utilized for drug delivery, diagnosis, and assessment of function in the CNS.

Real-Time Label-Free Targeting Assessment and in Vitro Characterization of Curcumin-Loaded Poly-lactic-co-glycolic Acid Nanoparticles for Oral Colon Targeting

The exploitation of curcumin for oral disease treatment is limited by its low solubility, poor bioavailability, and low stability. Surface-functionalized poly-lactic-co-glycolic acid (PLGA) nanoparticles (NPs) have shown promising results to ameliorate selective delivery of drugs to the gastro-intestinal tract. In this study, curcumin-loaded PLGA NPs (C-PLGA NPs) of about 200 nm were surface-coated with chitosan (CS) for gastro-intestinal mucosa adhesion, wheat germ agglutinin (WGA) for colon targeting or GE11 peptide for tumor colon targeting. Spectrometric and zeta potential analyses confirmed the successful functionalization of the C-PLGA NPs. Real-time label-free assessment of the cell membrane-NP interactions and NP cell uptake were performed by quartz crystal microbalance coupled with supported lipid bilayers and by surface plasmon resonance coupled with living cells. The study showed that CS-coated C-PLGA NPs interact with cells by the electrostatic mechanism, while both WGA- and GE11-coated C-PLGA NPs interact and are taken up by cells by specific active mechanisms. In vitro cell uptake studies corroborated the real-time label-free assessment by yielding a curcumin cell uptake of 7.3 ± 0.3, 13.5 ± 1.0, 27.3 ± 4.9, and 26.0 ± 1.3 μg per 10⁴ HT-29 cells for noncoated, CS-, WGA-, and GE11-coated C-PLGA NPs, respectively. Finally, preliminary in vivo studies showed that the WGA-coated C-PLGA NPs efficiently accumulate in the colon after oral administration to healthy Balb/c mice. In summary, the WGA- and GE11-coated C-PLGA NPs displayed high potential for application as active targeted carriers for anticancer drug delivery to the colon.

Grand challenges in nanomedicine

Nanotherapeutics and nanopharmaceuticals could achieve and facilitate earlier and more precise individual diagnosis, improve targeted therapies, reduce side effects, and enhance therapeutic monitoring. These advantages will improve quality of life, support a healthier and more independent aging population, and be instrumental in maximizing the cost-effectiveness of health care. However, the field of nanomedicine is at its early stage, most of the research still stays in the laboratory phase, and few success stories are translated into clinical trials and medical practice. This review will demonstrate the numerous challenges that are encountered during the development of commercial nanoparticle-based therapeutics and the possible solutions.

Selectively Biodegradable Polyesters: Nature-Inspired Construction Materials for Future Biomedical Applications

In the last half-century, the development of biodegradable polyesters for biomedical applications has advanced significantly. Biodegradable polyester materials containing external stimuli-sensitive linkages are favored in the development of therapeutic devices for pharmacological applications such as delivery vehicles for controlled/sustained drug release. These selectively biodegradable polyesters degrade after particular external stimulus (e.g., pH or redox potential change or the presence of certain enzymes). This review outlines the current development of biodegradable synthetic polyesters materials able to undergo hydrolytic or enzymatic degradation for various biomedical applications, including tissue engineering, temporary implants, wound healing and drug delivery.

Current Transport Systems and Clinical Applications for Small Interfering RNA (siRNA) Drugs

Small interfering RNAs (siRNAs) are an attractive new agent with potential as a therapeutic tool because of its ability to inhibit specific genes for many conditions, including viral infections and cancers. However, despite this potential, many challenges remain, including off-target effects, difficulties with delivery, immune responses, and toxicity. Traditional genetic vectors do not guarantee that siRNAs will silence genes in vivo. Rational design strategies, such as chemical modification, viral vectors, and non-viral vectors, including cationic liposomes, polymers, nanocarriers, and bioconjugated siRNAs, provide important opportunities to overcome these challenges. We summarize the results of research into vector delivery of siRNAs as a therapeutic agent from their design to clinical trials in ophthalmic diseases, cancers, respiratory diseases, and liver virus infections. Finally, we discuss the current state of siRNA delivery methods and the need for greater understanding of the requirements.

Intracellular Delivery of Trehalose for Cell Banking

Advances in stem cell technology and regenerative medicine have underscored the need for effective banking of living cells. Cryopreservation, using very low temperatures to achieve suspended animation, is widely used to store or bank cells for later use. This process requires the use of cryoprotective agents (CPAs) to protect cells against damage caused by the cooling and warming process. However, current popular CPAs like DMSO can be toxic to cells and must be thoroughly removed from cells before they can be used for research or clinical applications. Trehalose, a nontoxic sugar found in organisms capable of withstanding extreme cold or desiccation, has been explored as an alternative CPA. The disaccharide must be present on both sides of the cellular membrane to provide cryo-protection. However, trehalose is not synthesized by mammalian cells nor has the capability to diffuse through their plasma membranes. Therefore, it is crucial to achieve intracellular delivery of trehalose for utilizing the full potential of the sugar for cell banking. In this review, various methods that have been explored to deliver trehalose into mammalian cells for their banking at both cryogenic and ambient temperatures are surveyed. Among them, the nanoparticle-mediated approach is particularly exciting. Collectively, studies in the literature demonstrate the great potential of using trehalose as the sole CPA for cell banking, to facilitate the widespread use of living cells in modern medicine.

Suitability of 3D human brain spheroid models to distinguish toxic effects of gold and poly-lactic acid nanoparticles to assess biocompatibility for brain drug delivery

Background

The blood brain barrier (BBB) is the bottleneck of brain-targeted drug development. Due to their physico-chemical properties, nanoparticles (NP) can cross the BBB and accumulate in different areas of the central nervous system (CNS), thus are potential tools to carry drugs and treat brain disorders. In vitro systems and animal models have demonstrated that some NP types promote neurotoxic effects such as neuroinflammation and neurodegeneration in the CNS. Thus, risk assessment of the NP is required, but current 2D cell cultures fail to mimic complex in vivo cellular interactions, while animal models do not necessarily reflect human effects due to physiological and species differences.

Results

We evaluated the suitability of in vitro models that mimic the human CNS physiology, studying the effects of metallic gold NP (AuNP) functionalized with sodium citrate (Au-SC), or polyethylene glycol (Au-PEG), and polymeric polylactic acid NP (PLA-NP). Two different 3D neural models were used (i) human dopaminergic neurons differentiated from the LUHMES cell line (3D LUHMES) and (ii) human iPSC-derived brain spheroids (BrainSpheres). We evaluated NP uptake, mitochondrial membrane potential, viability, morphology, secretion of cytokines, chemokines and growth factors, and expression of genes related to ROS regulation after 24 and 72 h exposures. NP were efficiently taken up by spheroids, especially when PEGylated and in presence of glia. AuNP, especially PEGylated AuNP, effected mitochondria and anti-oxidative defense. PLA-NP were slightly cytotoxic to 3D LUHMES with no effects to BrainSpheres.

Conclusions

3D brain models, both monocellular and multicellular are useful in studying NP neurotoxicity and can help identify how specific cell types of CNS are affected by NP.

Electronic supplementary material

The online version of this article (10.1186/s12989-019-0307-3) contains supplementary material, which is available to authorized users.

Superparamagnetic iron oxide nanoparticles (SPIONs) as a multifunctional tool in various cancer therapies

Over the past two decades nanotechnology has become an important part of novel medical research. Researchers have made great progress in developing nanotechnology applications used for detecting and treating oncological diseases. Recently, many research groups have focused on the use of superparamagnetic iron oxide nanoparticles (SPIONs) in cancer treatment. Due to the range of therapeutic properties and possibilities of various modifications, SPIONs are a promising and multifunctional tool in various cancer therapies and may help to overcome the limitations of conventional therapies. Moreover, it is still necessary to develop new methods of treatment with expected properties, such as lower toxicity, long-lasting effectiveness and higher selectivity. Analyzing the literature data, we found that currently SPIONs are used in the transport of drugs, immunotherapy and hyperthermia. The main aim of this review is to present various cancer treatment therapies utilizing SPIONs, the importance of the experiments carried out by research groups and further perspectives in the nanotechnological use of SPIONs.

PLGA based particles as "drug reservoir" for antitumor drug delivery: characterization and cytotoxicity studies

Doxorubicin (DOX) is commonly used to treat several tumor types, but its severe side effects, primarily cardiotoxicity, represent a major limitation for its use in clinical settings. In this study we developed and characterized biodegradable and stable poly(D,L-lactic-co-glycolic) acid (PLGA) submicrocarriers employing an osmosis-based patented methodology, which allowed to optimize the drug loading efficiency up to 99%. Proceeding from this, we evaluated on MCF-7, a human breast cancer cell line, the ability of PLGA to promote the internalization of DOX and to improve its cytotoxicity in vitro. We found that the in vitro uptake efficiency is dramatically increased when DOX is loaded within PLGA colloidal carriers, which adhere to the cell membrane behaving as an efficient drug reservoir. In fact, the particles provide a diffusion-driven, sustained release of DOX across the cell membrane, resulting in high drug concentration. Accordingly, the cytotoxic analysis clearly showed that DOX-loaded PLGA exhibit a lower 50% inhibitory concentration than free DOX. The decay time of cell viability was successfully compared with DOX diffusion time constant from PLGA. The overall in vitro results highlight the potential of DOX-loaded PLGA particles to be employed as vectors with improved antitumor efficacy.

Harnessing Dendritic Cells for Poly (D,L-lactide-co-glycolide) Microspheres (PLGA MS)-Mediated Anti-tumor Therapy

With emerging success in fighting off cancer, chronic infections, and autoimmune diseases, immunotherapy has become a promising therapeutic approach compared to conventional therapies such as surgery, chemotherapy, radiation therapy, or immunosuppressive medication. Despite the advancement of monoclonal antibody therapy against immune checkpoints, the development of safe and efficient cancer vaccine formulations still remains a pressing medical need. Anti-tumor immunotherapy requires the induction of antigen-specific CD8+ cytotoxic T lymphocyte (CTL) responses which recognize and specifically destroy tumor cells. Due to the crucial role of dendritic cells (DCs) in initiating anti-tumor immunity, targeting tumor antigens to DCs has become auspicious in modern vaccine research. Over the last two decades, micron- or nanometer-sized particulate delivery systems encapsulating tumor antigens and immunostimulatory molecules into biodegradable polymers have shown great promise for the induction of potent, specific and long-lasting anti-tumor responses in vivo. Enhanced vaccine efficiency of the polymeric micro/nanoparticles has been attributed to controlled and continuous release of encapsulated antigens, efficient targeting of antigen presenting cells (APCs) such as DCs and subsequent induction of CTL immunity. Poly (D, L-lactide-co-glycolide) (PLGA), as one of these polymers, has been extensively studied for the design and development of particulate antigen delivery systems in cancer therapy. This review provides an overview of the current state of research on the application of PLGA microspheres (PLGA MS) as anti-tumor cancer vaccines in activating and potentiating immune responses attempting to highlight their potential in the development of cancer therapeutics.

Tunneling Nanotubular Expressways for Ultrafast and Accurate M1 Macrophage Delivery of Anticancer Drugs to Metastatic Ovarian Carcinoma

It is extremely difficult for cancer chemotherapy to control the peritoneal metastasis of advanced ovarian carcinoma given its inability to target disseminated tumors and the severe toxic side effects on healthy organs. Here, we report antitumor M1 macrophages developed as live-cell carriers that deliver anticancer drugs for the treatment of the metastatic ovarian carcinoma. Engineered doxorubicin-loaded M1 macrophages (M1-Dox) significantly enhanced tumor tropism by upregulation of CCR2 and CCR4 compared with their parent cells. Meanwhile, M1-Dox inhibited doxorubicin-induced tumor invasion, whereas commercial Lipo-Dox did not limit these side effects. Importantly, our data uncovered a drug delivery mechanism by which M1-Dox transferred drug cargoes into tumor cells  via a tunneling nanotube pathway. The tunneling nanotube network acted as a transportation expressway for ultrafast drug delivery of M1-Dox, leading to efficient ovarian carcinoma cell death. Furthermore, genetic, pharmacological, and physical perturbations of these tunneling nanotubes obviously decreased drug transfer of M1-Dox, which further validated the evident correlation between drug delivery of M1-Dox and tunneling nanotubes. Finally, in peritoneal metastatic ovarian carcinoma-burdened mice, M1-Dox specifically penetrated into and accumulated deep within disseminated neoplastic lesions compared with commercial Lipo-Dox, resulting in reducing metastatic tumors to a nearly undetectable level and significantly increasing overall survival. Overall, the strategy of engineered macrophages for ultrafast and accurate drug delivery via the tunneling nanotubular expressway potentially revolutionizes the treatment of metastatic ovarian carcinoma.

Novel Ran-RCC1 Inhibitory Peptide-Loaded Nanoparticles Have Anti-Cancer Efficacy In Vitro and In Vivo

The delivery of anticancer agents to their subcellular sites of action is a significant challenge for effective cancer therapy. Peptides, which are integral to several oncogenic pathways, have significant potential to be utilised as cancer therapeutics due to their selectivity, high potency and lack of normal cell toxicity. Novel Ras protein-Regulator of chromosome condensation 1 (Ran-RCC1) inhibitory peptides designed to interact with Ran, a novel therapeutic target in breast cancer, were delivered by entrapment into polyethylene glycol-poly (lactic-co-glycolic acid) PEG-PLGA polymeric nanoparticles (NPs). A modified double emulsion solvent evaporation technique was used to optimise the physicochemical properties of these peptide-loaded biodegradable NPs. The anti-cancer activity of peptide-loaded NPs was studied in vitro using Ran-expressing metastatic breast (MDA-MB-231) and lung cancer (A549) cell lines, and in vivo using Solid Ehrlich Carcinoma-bearing mice. The anti-metastatic activity of peptide-loaded NPs was investigated using migration, invasion and colony formation assays in vitro. A PEG-PLGA-nanoparticle encapsulating N-terminal peptide showed a pronounced antitumor and anti-metastatic action in lung and breast cancer cells in vitro and caused a significant reduction of tumor volume and associated tumor growth inhibition of breast cancer model in vivo. These findings suggest that the novel inhibitory peptides encapsulated into PEGylated PLGA NPs are delivered effectively to interact and deactivate Ran. This novel Ran-targeting peptide construct shows significant potential for therapy of breast cancer and other cancers mediated by Ran overexpression.

Exploiting Nanomaterial-mediated Autophagy for Cancer Therapy

Autophagy is a conserved process that is critical for sequestering and degrading proteins, damaged or aged organelles, and for maintaining cellular homeostasis under stress conditions. Despite its dichotomous role in health and diseases, autophagy usually promotes growth and progression of advanced cancers. In this context, clinical trials using chloroquine and hydroxychloroquine as autophagy inhibitors have suggested that autophagy inhibition is a promising approach for treating advanced malignancies and/or overcoming drug resistance of small molecule therapeutics (i.e., chemotherapy and molecularly targeted therapy). Efficient delivery of autophagy inhibitors may further enhance the therapeutic effect, reduce systemic toxicity, and prevent drug resistance. As such, nanocarriers-based drug delivery systems have several distinct advantages over free autophagy inhibitors that include increased circulation of the drugs, reduced off-target systemic toxicity, increased drug delivery efficiency, and increased solubility and stability of the encapsulated drugs. With their versatile drug encapsulation and surface-functionalization capabilities, nanocarriers can be engineered to deliver autophagy inhibitors to tumor sites in a context-specific and/or tissue-specific manner. This review focuses on the role of nanomaterials utilizing autophagy inhibitors for cancer therapy, with a focus on their applications in different cancer types.

Development of an advanced nanoformulation for the intracellular delivery of a caspase-3 selective activity-based probe

The ability to label active caspase-3 represents a useful pharmacodynamic strategy to determine the efficacy of anti-tumour drugs. Activity-based probes (ABPs) provide a method for the labelling of activated caspases and the recent development of hybrid combinatorial substrate libraries (HyCoSuL) has allowed for the generation of highly selective ABPs to discriminately label these proteases. Here using this approach, a novel caspase-3 selective ABP (CS1) has been developed and validated in apoptotic cells to selectively bind caspase-3 over the closely related caspase-7. However, a critical bottleneck for ABPs is their cell penetrance and therefore this cell-impermeable CS1 probe was subsequently formulated into PLGA-based nanoparticles (CS1-NPs). We demonstrate the ability of these particles to be taken up by the cells and facilitate intracellular delivery of the ABP to effectively label caspase 3 in response to apoptotic stimuli. This work forms the foundation of a novel approach for the labelling of caspase 3 and may have downstream utility to measure real time apoptosis in tumours and other organs.

MicroRNA replacement therapy in cancer

Despite the recent progress in cancer management approaches, the mortality rate of cancer is still growing and there are lots of challenges in the clinics in terms of novel therapeutics. MicroRNAs (miRNA) are regulatory small noncoding RNAs and are already confirmed to have a great role in regulating gene expression level by targeting multiple molecules that affect cell physiology and disease development. Recently, miRNAs have been introduced as promising therapeutic targets for cancer treatment. Regulatory potential of tumor suppressor miRNAs, which enables regulation of entire signaling networks within the cells, makes them an interesting option for developing cancer therapeutics. In this regard, over recent decades, scientists have aimed at developing powerful and safe targeting approaches to restore these suppressive miRNAs in cancerous cells. The present review summarizes the function of miRNAs in tumor development and presents recent findings on how miRNAs have served as therapeutic agents against cancer, with a special focus on tumor suppressor miRNAs (mimics). Moreover, the latest investigations on the therapeutic strategies of miRNA delivery have been presented.

Biodistribution, Safety and Organ Toxicity of Docetaxel-Loaded in HER-2 Aptamer Conjugated Ecoflex® Nanoparticles in a Mouse Xenograft Model of Ovarian Cancer

BACKGROUND

Docetaxel is a notably efficient anticancer drug administered for several types of malignancies including ovarian cancer. However, various side effects caused either by the nonspecific distribution of the active ingredient or by high contents of Tween 80 and ethanol in the currently marketed formulations, could even deprive the patients of the treatment.

OBJECTIVES

In the current study, a novel targeted delivery system composed of Ecoflex® polymeric nanoparticles loaded with docetaxel and equipped with HER-2 specific aptamer molecules was evaluated regarding blood and tissue toxicity, and biodistribution.

METHOD

The tumor-bearing nude mice, achieved by subcutaneous injection of SKOV-3 cells, were divided into four groups treated with normal saline, Taxotere®, targeted docetaxel nanoparticles, and non-targeted docetaxel nanoparticles. Few patents were alos cied in the article.

RESULTS

According to the results of hematologic evaluations, almost all hematologic parameters were in normal range with no significant difference among the four groups. Histopathological studies revealed that treatment with targeted nanoparticles caused a remarkable reduction in mitosis in tumor sections and overall reduced organ toxicity compared with Taxotere®. The only exception was spleen in which more damage was caused by the nanoparticles. The results of the biodistribution study were also in accordance with pathological assessments, with significantly lower drug concentration in non-tumor tissues, except for spleen, when targeted nanoparticles were used compared with Taxotere®.

CONCLUSION

These results could evidence the efficiency of the targeted delivery system in concentrating the drug cargo mostly in its site of action leading to the elimination of its adverse effects caused by exposure of other tissues to the cytotoxic agent.

Recent development in biodegradable nanovehicle delivery system-assisted immunotherapy

A schematic illustration of BNDS biodegradation and release antigen delivery for assisting immunotherapy.

BODIPY-loaded polymer nanoparticles: chemical structure of cargo defines leakage from nanocarrier in living cells

Hydrophobicity of a fluorescent cargo loaded into PLGA nanoparticles is crucial for minimizing its leakage in biological media.

Bait-and-Switch Supramolecular Strategy To Generate Noncationic RNA-Polymer Complexes for RNA Delivery

RNA interference (RNAi) requires the intracellular delivery of RNA molecules to initiate the neutralization of targeted mRNA molecules, inhibiting the expression or translation of the targeted gene. Current polymers and lipids that are used to deliver RNA molecules are generally required to be positively charged, to achieve complexation with RNA and the cellular internalization. However, positive surface charge has been implicated as the reason for toxicity in many of these systems. Herein, we report a novel strategy to generate noncationic RNA-polymer complexes for RNA delivery with low cytotoxicity. We use an in situ electrostatic complexation using a methylated pyridinium group, which is simultaneously removed during the RNA binding step. The resultant complexes demonstrate successful knockdown in preimplantation mammalian embryos, thus providing a new approach for nucleic acid delivery.

Polymer nanoparticles for the intravenous delivery of anticancer drugs: the checkpoints on the road from the synthesis to clinical translation

In this review article we discuss some of the key aspects concerning the development of a polymer-based nanoparticle formulation for intravenous drug delivery. Since numerous preparations fail before and during clinical trials, our aim is to emphasize the main issues that a nanocarrier has to face once injected into the body. These include biocompatibility and toxicity, drug loading and release, nanoparticle storage and stability, biodistribution, selectivity towards the target organs or tissues, internalization in cells and biodegradability. They represent the main checkpoints to define a polymer-based formulation as safe and effective. Indeed, this review is intended to provide guidelines to be followed in the early development of a new nanotherapeutic to hopefully increase the success rate of polymer-based formulations entering clinical trials. The corresponding requirements and characteristics are discussed in the context of some relevant case studies taken from the literature and mainly related to the delivery of lipophilic anticancer therapeutics.

Nanomedicine for anticancer and antimicrobial treatment: an overview

Nanoparticle-based treatment has become a potential therapeutic approach. The nanosize of these particles provides them with unique physicochemical properties and enhances their interaction with the biological system. Nanomaterials have the potential to overcome some of the major issues in the clinical world which may include cancer treatment and may be utilised to resolve the major problem of drug resistance in infection control. These particles are being used to improve present therapeutics by virtue of their shape, size and diverse intrinsic as well as chemical properties. The authors have discussed the use of nanoparticles in cancer treatment, infections caused by multidrug-resistant microbial strains and biofilm inhibition along with the detailed description of the current status of nanomaterials in the field of medicine.

Dissociation of 19F and fluorescence signal upon cellular uptake of dual-contrast perfluorocarbon nanoemulsions

OBJECTIVE

Perfluorocarbon nanoemulsions (PFCs) tagged with fluorescence dyes have been intensively used to confirm the in vivo ¹⁹F magnetic resonance imaging (MRI) localization of PFCs by post mortem histology or flow cytometry. However, only limited data are available on tagged PFCs and the potential dissociation of fluorescence and ¹⁹F label after cellular uptake over time.

MATERIALS AND METHODS

PFCs were coupled to rhodamine (Rho) or carboxyfluorescein (Cfl) and their fate was analyzed after in vitro uptake by J774, RAW and CHO cells by flow cytometry and ¹⁹F MRI. In separate in vivo experiments, the dual-labelled emulsions were intravenously applied into mice and their distribution was monitored in spleen and liver over 24 h. In a final step, time course of fluorescence and ¹⁹F signals from injected emulsions were tracked in a local inflammation model making use of a subcutaneous matrigel depot doped with LPS (lipopolysaccharide).

RESULTS

Internalization of fluorescence-labelled PFCs was associated with a substantial whitening over 24 h in all macrophage cell lines while the ¹⁹F signal remained stable over time. In all experiments, ^CflPFCs were more susceptible to bleaching than ^RhoPFCs. After intravenous injection of ^RhoPFCs, the fluorescence signal in spleen and liver peaked after 30 min and 2 h, respectively, followed by a successive decrease over 24 h, whereas the ¹⁹F signal continuously increased during this observation period. Similar results were found in the matrigel/LPS model, where we observed increasing ¹⁹F signals in the inflammatory hot spot over time while the fluorescence signal of immune cells isolated from the matrigel depot 24 h after its implantation was only marginally elevated over background levels. This resulted in a massive underestimation of the true PFC deposition in the reticuloendothelial system and at inflammatory hot spots.

CONCLUSION

Cellular uptake of fluorescently tagged PFCs leads to a dissociation of the fluorescence and the ¹⁹F label signal over time, which critically impacts on interpretation of long-term experiments validated by histology or flow cytometry.

Nanoparticle eluting-angioplasty balloons to treat cardiovascular diseases

Nanoparticles (NPs) can be used to locally deliver anti-restenosis drugs when they are infused directly to the injured arteries after intervention procedures such as angioplasty. However, the efficacy of transferring NPs via infusion to the arterial wall is limited, at least partially, due to poor NP retention on the inner artery wall. To improve NP retention, angioplasty balloons coated with drug-loaded NPs were fabricated via either layer-by-layer (LbL) electrostatic coating or acrylic-based hydrogel (AAH) coating techniques. Three types of NPs, namely poly (lactide-co-glycolide) (PLGA), biodegradable photo-luminescent PLGA and urethane doped polyester were studied. The transfer efficacy of NPs from various coatings to the arterial wall were further evaluated to find the optimal coating conditions. The ex vivo NP transfer studies showed significantly more NPs being transferred to the rat arterial wall after the angioplasty procedure by the AAH coating (95% transfer efficiency) compared to that of the LbL technique (60%) and dip coating (20%) under flow conditions (10 dyn/cm²). Our results suggest that the AAH coating of drug-loaded NPs on the angioplasty balloon could potentially provide superior retention of drug-loaded NPs onto the arterial wall for a better local delivery of drug-loaded NPs to effectively treat arterial diseases.