Size-controlled biodegradable nanoparticles: Preparation and size-dependent cellular uptake and tumor cell growth inhibition

Advanced protein-embedded bimetallic nanocomposite optimized for in vivo fluorescence and magnetic resonance bimodal imaging

HYPOTHESIS

The development of bimodal imaging probes represents a hot topic of current research. Herein, we deal with developing an innovative bimodal contrast agent enabling fluorescence imaging (FI)/magnetic resonance imaging (MRI) and, simultaneously, consisting of biocompatible nanostructures. Optimized synthesis of advanced protein-embedded bimetallic (APEBM) nanocomposite containing luminescent gold nanoclusters (AuNC) and superparamagnetic iron oxide nanoparticles (SPION), suitable for in vivo dual-modal FI/MR imaging is reported.

EXPERIMENTS

The APEBM nanocomposite was prepared by a specific sequential one-pot green synthetic approach that is optimized to increase metals (Au, Fe) content and, consequently, the imaging ability of the resulting nanostructures. The protein matrix, represented by serum albumin, was intentionally chosen, and used since it creates an efficient protein corona for both types of optically/magnetically-susceptible nanostructures (AuNC, SPION) and ensures biocompatibility of the resulting APEBM nanocomposite although it contains elevated metal concentrations (approx. 1 mg·mL-1 of Au, around 0.3 mg·mL-1 of Fe). In vitro and in vivo imaging was performed.

FINDINGS

Successful in vivo FI and MRI recorded in healthy mice corroborated the applicability of the APEBM nanocomposite and, simultaneously, served as a proof of concept concerning the potential future exploitation of this new FI/MRI bimodal contrast agent in preclinical and clinical practice.

Layered rare-earth hydroxides as multi-modal medical imaging probes: particle size optimisation and compositional exploration

Recently, layered rare-earth hydroxides (LRHs) have received growing attention in the field of theranostics. We have previously reported the hydrothermal synthesis of layered terbium hydroxide (LTbH), which exhibited high biocompatibility, reversible uptake of a range of model drugs, and release-sensitive phosphorescence. Despite these favourable properties, LTbH particles produced by the reported method suffered from poor size-uniformity (670 ± 564 nm), and are thus not suitable for therapeutic applications. To ameliorate this issue, we first derive an optimised hydrothermal synthesis method to generate LTbH particles with a high degree of homogeneity and reproducibility, within a size range appropriate for in vivo applications (152 ± 59 nm, n = 6). Subsequently, we apply this optimised method to synthesise a selected range of LRH materials (R = Pr, Nd, Gd, Dy, Er, Yb), four of which produced particles with an average size under 200 nm (Pr, Nd, Gd, and Dy) without the need for further optimisation. Finally, we incorporate Gd and Tb into LRHs in varying molar ratios (1 : 3, 1 : 1, and 3 : 1) and assess the combined magnetic relaxivity and phosphorescence properties of the resultant LRH materials. The lead formulation, LGd1.41Tb0.59H, was demonstrated to significantly shorten the T2 relaxation time of water (r2 = 52.06 mM-1 s-1), in addition to exhibiting a strong phosphorescence signal (over twice that of the other LRH formulations, including previously reported LTbH), therefore holding great promise as a potential multi-modal medical imaging probe.

Hopping the Hurdle: Strategies to Enhance the Molecular Delivery to the Brain through the Blood-Brain Barrier

Modern medicine has allowed for many advances in neurological and neurodegenerative disease (ND). However, the number of patients suffering from brain diseases is ever increasing and the treatment of brain diseases remains an issue, as drug efficacy is dramatically reduced due to the existence of the unique vascular structure, namely the blood-brain barrier (BBB). Several approaches to enhance drug delivery to the brain have been investigated but many have proven to be unsuccessful due to limited transport or damage induced in the BBB. Alternative approaches to enhance molecular delivery to the brain have been revealed in recent studies through the existence of molecular delivery pathways that regulate the passage of peripheral molecules. In this review, we present recent advancements of the basic research for these delivery pathways as well as examples of promising ventures to overcome the molecular hurdles that will enhance therapeutic interventions in the brain and potentially save the lives of millions of patients.

Sulfonated vitamin K3 mediated bimetallic metal-organic framework for multistage augmented cancer therapy

Chemodynamic therapy (CDT) relying on Fenton reaction has emerged as a promising strategy for tumor treatment. However, its clinical efficacy is hindered by the inadequate reactive oxygen species (ROS) and the potential cytotoxicity towards normal cells. To address these challenges, we have successfully developed a multistage augmented cancer therapy system based on bimetallic metal-organic framework (BMOF) that amplifies ROS and facilitates tumor-specific therapeutic effects. By employing a simple one-pot self-assembly approach, we synthesized SVK3@ZnCo-ZIF in which sulfonated vitamin K3 (SVK3) was encapsulated within ZnCo-ZIF BMOF. The results revealed that the incorporation of Zn atoms significantly diluted the Fenton activity of Co atoms towards normal cells. Notably, SVK3@ZnCo-ZIF underwent pH-controlled decomposition triggered by the tumor microenvironment (TME), thus releasing SVK3, Co2+ and Zn2+. Specifically, the H2O2 levels in tumors was effectively elevated by the interaction of SVK3 with NAD(P)H quinone oxidoreductase-1 (NQO-1). It thus enhanced the Fenton activity of Co2+. Moreover, the release of Zn2+ ions can induce cellular dysfunction and mitochondrial damage, thereby promoting the generation of ROS and subsequent cell death. The synergistic combination of CDT, SVK3 chemotherapy, and Zn2+-interfered therapy greatly facilitated apoptosis of tumor cells. Collectively, our investigations demonstrate the efficacy of such system in selectively inducing toxicity in cancer cells while minimizing detrimental effects on normal cells.

Thymoquinone-loaded lipid nanocapsules with promising anticancer activity for colorectal cancer

Colorectal cancer (CRC) is the third most common worldwide. Depending on its stage, chemotherapy is usually given after surgery when CRC has already metastasized to other organs like the liver or lungs. Unfortunately, the current antineoplastics used for CRC therapies involve toxicity and side effects due to their lack of site-specificity. To overcome the drawbacks of heavy chemotherapy, this study proposes to assess the efficacy of thymoquinone (TQ), a bioactive constituent of black seeds (Nigella sativa), as an antiproliferative and pro-apoptotic agent on an experimental CRC model in mice. TQ was encapsulated in lipid nanocapsules (LNCs), used as nanocarriers, in order to increase its specificity and cell absorption. TQ-loaded LNCs (TQ-LNCs) have a diameter of 58.3 ± 3.7 nm and 87.7 ± 4.5% TQ encapsulation efficiency. In turn, in vivo studies showed that the intratumoral administration of TQ-LNCs decreased the tumor size in colorectal cancer bearing mice compared to the control group. TQ-LNCs were more effective than free TQ for inducing tumor cell death. These results highlight the potential of TQ entrapped in LNCs as an anticancer agent for CRC treatment.

Intraocular siRNA Delivery Mediated by Penetratin Derivative to Silence Orthotopic Retinoblastoma Gene

Gene therapy brings a ray of hope for inherited ocular diseases that may cause severe vision loss and even blindness. However, due to the dynamic and static absorption barriers, it is challenging to deliver genes to the posterior segment of the eye by topical instillation. To circumvent this limitation, we developed a penetratin derivative (89WP)-modified polyamidoamine polyplex to deliver small interference RNA (siRNA) via eye drops to achieve effective gene silencing in orthotopic retinoblastoma. The polyplex could be spontaneously assembled through electrostatic and hydrophobic interactions, as demonstrated by isothermal titration calorimetry, and enter cells intactly. In vitro cellular internalization revealed that the polyplex possessed higher permeability and safety than the lipoplex composed of commercial cationic liposomes. After the polyplex was instilled in the conjunctival sac of the mice, the distribution of siRNA in the fundus oculi was significantly increased, and the bioluminescence from orthotopic retinoblastoma was effectively inhibited. In this work, an evolved cell-penetrating peptide was employed to modify the siRNA vector in a simple and effective way, and the formed polyplex interfered with intraocular protein expression successfully via noninvasive administration, which showed a promising prospect for gene therapy for inherited ocular diseases.

Self-assembly of DNA nanospheres with controllable size and self-degradable property for enhanced antitumor chemotherapy

Controllable size, self-degradability and targeting property are important for a precise improvement of anticancer effects and reduction of side effects of drug vehicles. Here, a series of DNA nanospheres with controllable size and self-degradation ability were constructed through the hybridization of two i-motif strands and two linker strands for targeted cancer therapy. DNA nanospheres with different sizes were fabricated by regulating the linker sequence, and their pH-responsive self-degradation property was realized by the introduction of the i-motif strand. Moreover, the ZY11 aptamer was introduced to endow the DNA nanospheres with targeting property toward SMMC-7721 cancer cells. The results revealed that the appropriate size of DNA nanospheres (80 nm) highly promoted the internalization by mammalian cells. The results of DLS, AFM and CD spectra showed that the DNA nanospheres were stable in a physiological environment but they self-degraded in a slightly acidic environment due to the existence of the i-motif strand. Moreover, the fluorescence of DOX@AP-NSs2 was triple at pH = 5.0 than at pH = 7.4, which further confirmed the pH-responsive drug release performance. The above results proved that the use of DOX@AP-NSs2 is a promising approach to accelerate the rapid release of drugs into the tumors and avoid drug leakage into the normal tissue. The results at a cellular level and in vivo confirmed the pH-responsive targeted antitumor effect. Hence, the novel DNA nanospheres with controllable size and self-degradable property represent a potential tool for targeted drug delivery and cancer therapy.

Fabrication, bacteriostasis and osteointegration properties researches of the additively-manufactured porous tantalum scaffolds loading vancomycin

Infected bone defects (IBDs) remains a challenging problem for orthopedists. Clinically, routine management for IBDs has two stages: debridement and systematic antibiotics administration to control infection, and secondary grafting to repair bone defects. Whereas the efficacy is not satisfactory, because the overuse of antibiotics may lead to systemic toxicity, and the emergence of drug-resistant bacteria, as well as the secondary surgery would cause additional trauma and economic burden to the patients. Therefore, it is imperative to develop a novel scaffold for one-stage repair of IBDs. In this study, vancomycin (Van) was encapsulated into poly(lactic co-glycolic acid) (PLGA) microspheres through the double emulsion method, which were then loaded into the additively-manufactured porous tantalum (AM-Ta) through gelatin methacryloyl (GelMA) hydrogel to produce the composite Ta/GelMA hydrogel (Gel)/PLGA/vancomycin(Van) scaffolds for repairing IBDs. Physiochemical characterization of the newly-developed scaffold indicated that the releasing duration of Van was over 2 weeks. Biological experiments indicated good biocompatibility of the composite scaffold, as well as bacteriostasis and osteointegration properties, which showed great potential for clinical application. The construction of this novel scaffold would provide new sight into the development of orthopaedic implants, shedding a novel light on the treatment of IBDs.

3D Gradient and Linearly Aligned Magnetic Microcapsules in Nerve Guidance Conduits with Remotely Spatiotemporally Controlled Release to Enhance Peripheral Nerve Repair

Although numerous strategies have been implemented to develop nerve guidance conduits (NGCs) to treat peripheral nerve injury (PNI), functionalization of an NGC to make it remotely controllable for providing spatiotemporal modulation on in situ nerve tissues remains a challenge. In this study, a gelatin/silk (GS) hydrogel was used to develop an NGC based on its self-owned reversible thermoresponsive sol-to-gel phase transformation ability that permitted rapid three-dimensional (3D) micropatterning of the incorporated nerve growth factor (NGF)-loaded magnetic poly(lactic-co-glycolic acid) (PLGA) microcapsules (called NGF@MPs) via multiple magnetic guidance. The thermally controllable viscosity of GS enabled the rapid formation of a 3D gradient and linearly aligned distribution of NGF@MPs, leading to magnetically controlled 3D gradient release of NGF to enhance topographical nerve guidance and wound healing in PNIs. Particularly, the as-formed micropatterned hydrogel, called NGF@MPs-GS, showed corrugation topography with a pattern height H of 15 μm, which resulted in the linear axon alignment of more than 90% of cells. In addition, by an external magnetic field, spatiotemporal controllability of NGF release was obtained and permitted neurite elongation that was almost 2-fold longer than that in the group with external addition of NGF. Finally, an NGC prototype was fabricated and implanted into the injured sciatic nerve. The patterned implant, assisted by magnetic stimulation, demonstrated accelerated restoration of motor function within 14 days after implantation. It further contributed to the enhancement of axon outgrowth and remyelination after 28 days. This NGC, with controllable mechanical, biochemical, and topographical cues, is a promising platform for the enhancement of nerve regeneration.

Effect of Organic Solvents on a Production of PLGA-Based Drug-Loaded Nanoparticles Using a Microfluidic Device

The translation of nanoparticles (NPs) from laboratory to clinical settings is limited, which is not ideal. One of the reasons for this is that we currently have limited ability to precisely regulate various physicochemical parameters of nanoparticles. This has made it difficult to rapidly perform targeted screening of drug preparation conditions. In this study, we attempted to broaden the range of preparation conditions for particle size-modulated poly(lactic-co-glycolic-acid) (PLGA) NP to enhance their applicability for drug delivery systems (DDS). This was done using a variety of organic solvents and a glass-based microfluidic device. Furthermore, we compared the PDMS-based microfluidic device to the glass-based microfluidic device in terms of the possibility of a wider range of preparation conditions, especially the effect of different solvents on the size of the PLGA NPs. PLGA NPs with different sizes (sub-200 nm) were successfully prepared, and three different types of taxanes were employed for encapsulation. The drug-loaded NPs showed size-dependent cytotoxicity in cellular assays, regardless of the taxane drug used.

Preparation of size-tunable sub-200 nm PLGA-based nanoparticles with a wide size range using a microfluidic platform

The realization of poly (lactic-co-glycolic acid) nanoparticles (PLGA NPs) from laboratory to clinical applications remains slow, partly because of the lack of precise control of each condition in the preparation process and the rich selectivity of nanoparticles with diverse characteristics. Employing PLGA NPs to establish a large range of size-controlled drug delivery systems and achieve size-selective drug delivery targeting remains a challenge for therapeutic development for different diseases. In this study, we employed a microfluidic device to control the size of PLGA NPs. PLGA, poly (ethylene glycol)-methyl ether block poly (lactic-co-glycolide) (PEG-PLGA), and blend (PLGA + PEG-PLGA) NPs were engineered with defined sizes. Blend NPs exhibit the widest size range (40–114 nm) by simply changing the flow rate conditions without changing the precursor (polymer molecular weight, concentration, and chain segment composition). A model hydrophobic drug, paclitaxel (PTX), was encapsulated in the NPs, and the PTX-loaded NPs maintained a large range of controllable NP sizes. Furthermore, size-controlled NPs were used to investigate the effect of particle size of sub-200 nm NPs on tumor cell growth. The 52 nm NPs showed higher cell growth inhibition than 109 nm NPs. Our method allows the preparation of biodegradable NPs with a large size range without changing polymer precursors as well as the nondemanding fluid conditions. In addition, our model can be applied to elucidate the role of particle sizes of sub-200 nm particles in various biomedical applications, which may help develop suitable drugs for different diseases.

A Novel Berberine–Glycyrrhizic Acid Complex Formulation Enhanced the Prevention Effect to Doxorubicin-Induced Cardiotoxicity by Pharmacokinetic Modulation of Berberine in Rats

Developing a new drug delivery system is one of the useful approaches to overcome the limited use of berberine (BBR) to enhance its absorption and bioavailability. We prepared a novel berberine–glycyrrhizic acid (BBR–GL) complex formulation to increase the plasma concentration and bioavailability of BBR by improving BBR solubility and lowering the absorption barrier. The complex formulation with BBR and GL in the ratio 1:1 was developed through the self-assembly process and evaluated in vitro. Compared with BBR and BBR/GL physical mixture, the BBR–GL complex showed different characteristics by SEM, DSC, FT-IR, and PXRD measurement. In pharmacokinetic evaluation, the BBR–GL complex significantly increased the plasma concentration of BBR and the major metabolite berberrubine (BBB), with the AUC of BBR elevated to 4.43-folds, while the complex was safe as BBR. Furthermore, doxorubicin (DOX) was used to induce cardiotoxicity. Hematological study, histopathological examinations, electrocardiography (ECG), cardiac secretion measurement, and biochemical index analysis proved that the model of doxorubicin-induced cardiotoxicity (DIC) was conducted successfully. With the AUC of BBR increasing in the BBR–GL complex and the absorbed complex itself, the BBR–GL complex enhanced prevention effect to DIC and exhibited a significant prevention effect to attenuate heart damage. Our findings demonstrated that a novel BBR-loaded BBR–GL complex formulation could increase BBR plasma concentration. Improvement of BBR bioavailability by the BBR–GL complex could coordinate with GL to attenuate DIC. Concerning the safety of the drug delivery system at present, the BBR–GL complex could be a potential therapeutic formulation for the prevention of cardiac damage in the clinical application of doxorubicin.

Exploring the intrinsic micro-/nanoparticle size on their in vivo fate after lung delivery

Micro-/nanocarriers due to their significant advantages are widely investigated in pulmonary drug delivery. However, different size carriers have varied drug release rate, concealing the effect of particle size on the fate of drugs in vivo. Therefore, by keeping drug release rate comparable, the objective of this study is to elucidate the influence of particle size itself on drug in vivo fate after intratracheal instillation to mice. Here, using paclitaxel (PTX) as a drug model, 100 nm, 300 nm, 800 nm, and 2500 nm poly(lactide-co-glycolide) (PLGA) particles with the same release rate were prepared. It was demonstrated that the in vivo fate of particles after lung delivery was size-dependent. Consistent with most reports of model particles with neglected release kinetics, the mucus penetration capacity in airtifical mucus decreased with increasing particle size and there is no significant difference between 800 nm and 2500 nm particles. The in vivo airway distribution experiments confirmed the results of the in vitro mucus penetration study, that is, the smaller the particles, the more distributed in the airway. Both in vitro and in vivo macrophage uptake results confirmed that the larger particles were more readily taken up by macrophages. In contrast, the uptake of smaller particles in A549 cells was higher than that of larger particles. Some new findings were disclosed in lung retention, lung absorption and lung targeting. Different from previous reports, this study demonstrated that particles with smaller size had longer lung retention, AUC_(0-t) in bronchoalveolar lavage fluid (BALF) of 100 nm particles was 1.6, 1.9, 2.5 times higher than that of 300 nm, 800 nm, and 2500 nm particles and 11.7 times of the PTX solution group. The same trend was observed in lung tissue absorption, the AUC_(0-t) in the lavaged lung of 100 nm particles was 1.8, 2.2, 2.8, 8.6 times higher than that of 300 nm, 800 nm, 2500 nm particles and PTX solution groups, respectively. The lung targeting efficiency was particles size independent. In conclusion, the in vivo fate of particles with the same release kinetics after intratracheal instillation is size-dependent, smaller size particles are conducive for lung retention and lung absorption. Overall, our study provided scientific guidance for the rational design of particle based pulmonary drug delivery system.

Glycyrrhetinic acid nanoparticles combined with ferrotherapy for improved cancer immunotherapy

Programmed cell death protein 1 (PD-1)/Programmed Cell Death Ligand 1 (PD-L1) blockade immunotherapy has emerged as a promising strategy to treat both solid and hematological malignancies. Despite the considerable therapeutic effects obtained in pre-clinical and clinical studies, PD-1/PD-L1 blockade therapy is still limited by the low benefit rates and a large number of patients still do not respond to this treatment. In this study, we developed a highly efficient and cancer-specific immunogenic cell death nanoinducer for effective tumor immunotherapy. A leukocyte membrane coated poly (lactic-co-glycolic acid) encapsulating glycyrrhetinic acid (GCMNPs) was developed to enhance targeting, tumor-homing capacity, and reduce toxicity in vivo. GCMNPs could induce ferroptosis in acute myeloid leukemia and colorectal cancer cells by downregulating glutathione-dependent peroxidases 4, leading to increased lipid peroxidation levels. Moreover, GCMNPs and ferumoxytol could synergistically enhance Fe-dependent cytotoxicity through the Fenton reaction. Finally, in vivo studies showed that GCMNPs synergized with ferumoxytol and anti-PD-L1 synergistically improve T-cell immune response against leukemia and colorectal tumor. This study anticipated that the combination of glycyrrhetinic acid-based nanomaterials and ferrotherapy would provide further insights into anti-cancer immune response to PD-1/PD-L1 blockade for both solid and hematological malignancies. STATEMENT OF SIGNIFICANCE: Despite the considerable therapeutic effects obtained in pre-clinical and clinical studies, PD-1/PD-L1 blockade therapy is still limited by the low benefit rates and a large number of patients still do not respond to this treatment. We designed a glycyrrhetinic acid-based nanoplatform as a new ICD inducer (GCMNPs), with high cancer cell specificity and reduced toxicity to AML and CRC. GCMNPs cooperates with ferumoxytol to promote a Fenton reaction and induce ferroptosis. Moreover, the combination of GCMNPs and ferumoxytol enhanced the blockage of PD-1/PD-L1 to activate T cells, subsequently generating a systemic immune response in CRC and AML mouse models. This pre-clinical findings provide the proof-of-concept of combination of glycyrrhetinic acid-based nanomaterials and ferrotherapy as an "ICD nano-inducer" and immunotherapeutic agent for treating cancer.

Light-Triggered Efficient Sequential Drug Delivery of Biomimetic Nanosystem for Multimodal Chemo-, Antiangiogenic, and Anti-MDSC Therapy in Melanoma

In view of the multiple pathological hallmarks of tumors, nanosystems for the sequential delivery of various drugs whose targets are separately located inside and outside tumor cells are desired for improved cancer therapy. However, current sequential delivery is mainly achieved through enzyme- or acid-dependent degradation of the nanocarrier, which would be influenced by the heterogeneous tumor microenvironment, and unloading efficiency of the drug acting on the target outside tumor cells is usually unsatisfactory. Here, a light-triggered sequential delivery strategy based on a liposomal formulation of doxorubicin (DOX)-loaded small-sized polymeric nanoparticles (DOX-NP) and free sunitinib in the aqueous cavity, is developed. The liposomal membrane is doped with photosensitizer porphyrin-phospholipid (PoP) and hybridized with red blood cell membrane to confer biomimetic features. Near-infrared light-induced membrane permeabilization triggers the "ultrafast" and "thorough" release of sunitinib (100% release in 5 min) for antiangiogenic therapy and also myeloid-derived suppressor cell (MDSC) inhibition to reverse the immunosuppressive tumor environment. Subsequently, the small-sized DOX-NP liberated from the liposomes is more easily uptaken by tumor cells for improved immunogenic chemotherapy. RNA sequencing and immune-related assay indicates therapeutic immune enhancement. This light-triggered sequential delivery strategy demonstrates the potency in cancer multimodal therapy against multiple targets in different spatial positions in tumor microenvironment.

A generic model based on the properties of nanoparticles and cells for predicting cellular uptake

Nanoparticles (NPs) are widely used in industry and technology due to their small size and versatility, which makes them easy to enter organisms and pose threats to human and ecological health. Given the particularity and complex structure of NPs, statistical models alone cannot reliably predict uptake. Hence, we developed a generic model for predicting the cellular uptake of NPs with organic coatings, based on physicochemical interactions underlying uptake. The model utilized the concentration, experimental conditions and properties of NPs viz. size, surface coating and coverage. These parameters were converted to surface energy components and surface potentials, and combined with the components and potential for a cell membrane. For NPs uptake, we constructed energetic profiles and barriers for adsorption and permeation onto/through cell membranes. The relationships derived were compared to experimental uptake data. The model provided accurate and robust uptake estimates for neutrally charged unhalogenated NPs and six different cell types. We envision that the model provides a reference for cellular accumulation of neutral NPs and (ecological/human) risk assessment of NPs or microparticles.

Local drug delivery using poly(lactic-co-glycolic acid) nanoparticles in thermosensitive gels for inner ear disease treatment

Intratympanic (IT) therapies have been explored to address several side effects that could be caused by systemic administration of steroids to treat inner ear diseases. For effective drug delivery to the inner ear, an IT delivery system was developed using poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) and thermosensitive gels to maintain sustained release. Dexamethasone (DEX) was used as a model drug. The size and zeta potential of PLGA NPs and the gelation time of the thermosensitive gel were measured. In vitro drug release was studied using a Franz diffusion cell. Cytotoxicity of the formulations was investigated using SK-MEL-31 cells. Inflammatory responses were evaluated by histological observation of spiral ganglion cells and stria vascularis in the mouse cochlea 24 h after IT administration. In addition, the biodistribution of the formulations in mouse ears was observed by fluorescence imaging using coumarin-6. DEX-NPs showed a particle size of 150.0 ± 3.2 nm in diameter and a zeta potential of −18.7 ± 0.6. The DEX-NP-gel showed a gelation time of approximately 64 s at 37 °C and presented a similar release profile and cytotoxicity as that for DEX-NP. Furthermore, no significant inflammatory response was observed after IT administration. Fluorescence imaging results suggested that DEX-NP-gel sustained release compared to the other formulations. In conclusion, the PLGA NP-loaded thermosensitive gel may be a potential drug delivery system for the inner ear.

Novel injectable progesterone-loaded nanoparticles embedded in SAIB-PLGA in situ depot system for sustained drug release

Poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) have attracted considerable interest in the medical community as a sustained-release drug delivery system for localized treatment. However, it is currently a grand challenge to simultaneously achieve low-dose drugs, stable and prolonged drug release, and long-term retention circumventing uptake by macrophages. Here, we construct a solvent-exchange in-situ depot system by incorporating progesterone (PRG) loaded PLGA NPs into a sucrose acetate isobutyrate (SAIB) and PLGA matrix for the long term treatment of Assisted Reproductive Technology (ART). The results showed that different solvent and PLGA contents could affect the drug release rate of PRG NPs-SAIB-PLGA in-situ depot system (PSPIDS). When DMSO was used as solvent with the addition of 8% PLGA to the depot, PSPIDS could achieve a constant drug release with no burst for 2 weeks in vitro. After a single intramuscular injection, such PSPIDS showed higher drug concentration and AUC (6773.0 ± 348.8 μg/L·h) over the entire 7-day testing period compared with the commercial multiple-day-dosing intramuscular PRG-oil solution (1914.5 ± 180.7 μg/L·h) in vivo. Importantly, PSPIDS could be administered at a dose of 3.65 mg/kg, which was one fourth of dose required for PRG-oil solution. The results demonstrate that PRG NPs could successfully achieve both reduced administered dosage and burst release, and therefore that PSPIDS is a promising long-acting composite system for hydrophobic drugs.

Natural Nano-Drug Delivery System in Coptidis Rhizoma Extract with Modified Berberine Hydrochloride Pharmacokinetics

Purpose

This study aimed to evaluate the pharmaceutical and pharmacokinetic effects of the natural nanoparticles (Nnps) isolated from Coptidis Rhizoma extract on berberine hydrochloride (BBR) and systematically explore the related mechanisms.

Methods

Firstly, Nnps were isolated from Coptidis Rhizoma extract and then an Nnps-BBR complex was prepared. After qualitative and quantitative analysis in terms of size, Zeta potential, morphology, and composition of the Nnps and the Nnps-BBR complex, the effects of the Nnps on the crystallization of BBR were characterized. The effects of the Nnps on the solubility and dissolution of BBR were then evaluated. In addition, the effects of the Nnps on BBR in terms of cellular uptake, transmembrane transport, metabolic stability, and pharmacokinetics in mice were studied.

Results

The Nnps had an average size of 166.6 ± 1.3 nm and Zeta potential of −12.5 ± 0.2 mV. The Nnps were formed by denaturation of co-existing plant proteins with molecular weight < 30 kDa. The Nnps adsorbed or dispersed BBR, thereby promoting BBR transformation from crystal to amorphous form and improving its solubility and dissolution. The Nnps carried and promoted BBR uptake by human colonic adenocarcinoma (Caco-2) cells via caveolae-mediated endocytosis, reducing P-gp-mediated efflux of BBR in mice gut sacs and Madin-Darby canine kidney cells stably expressing the transporter P-gp (MDCK-MDR1) cells. Moreover, the Nnps improved BBR metabolic stability in mouse intestinal S9, promoting BBR intestinal absorption in mice, as shown by increased peak BBR concentration (C_max, 1182.3 vs 310.2 ng/mL) and exposure level (AUC_{0–12 h}, 2842.8 vs 1447.0 ng·h/mL) in mouse portal vein. In addition, the Nnps increased BBR exposure level in mouse livers (95,443.2 vs 43,586.2 ng·h/g liver).

Conclusion

The proteinaceous nanoparticles isolated from Coptidis Rhizoma extract can form a natural nano-drug delivery system with BBR, thereby significantly improving the pharmacokinetics of oral BBR.

Colon-targeted delivery of tacrolimus using pH-responsive polymeric nanoparticles for murine colitis therapy

The present study aimed at constructing an oral nanoparticle delivery system loaded with tacrolimus (FK506) for effective treatment of inflammatory bowel disease. A FK506/HP-β-CD inclusion compound was prepared by grinding to increase drug solubility. To address the side- effects in non-target organs and systemic toxicity of FK506, pH-responsive Eudragit S100 (ES100) and hyaluronic acid (HA) with high affinity to CD44 receptor were adsorbed onto the surface of chitosan (CS) nanoparticles loaded with FK506/HP-β-CD through electrostatic interactions to obtain FK506@ES100/HA/CS/HP-β-CD nanoparticles (FK506@EHCh NPs). Caco-2 cells and Raw 264.7 macrophages were used to confirm the lack of cytotoxicity and good uptake ability of the newly generated nanoparticles. FK506@EHCh NPs significantly suppressed secretion of TNF-α, IL-1β and IL-6 by LPS-activated Raw 264.7 macrophages. A dextran sodium sulfate (DSS)-induced inflammatory bowel disease (IBD) murine model was established to further confirm the colon targeting and in vivo efficacy of oral IR-775@EHCh NPs. Based on the collective results, we conclude that packaging FK506 into active targeting nanocarriers sensitive to pH facilitates concentration of the drug within the sites of intestinal inflammation and improves the drug levels in target tissues, thus avoiding systemic side-effects and improving efficacy. In view of the promising results obtained in this study, the potential of EHCh nanoparticles for drug delivery and targeted treatment of inflammatory bowel disease warrants further investigation.

Metal Phenolic Network-Integrated Multistage Nanosystem for Enhanced Drug Delivery to Solid Tumors

Metal-phenolic networks (MPNs) are an emerging class of supramolecular surface modifiers with potential use in various fields including drug delivery. Here, the development of a unique MPN-integrated core-satellite nanosystem (CS-NS) is reported. The "core" component of CS-NS comprises a liposome loaded with EDTA (a metal ion chelator) in the aqueous core and DiR (a near-infrared photothermal transducer) in the bilayer. The "satellite" component comprises mesoporous silica nanoparticles (MSNs) encapsulating doxorubicin and is coated with a Cu²⁺ -tannic acid MPN. Liposomes and MSNs self-assemble into the CS-NS through adhesion mediated by the MPN. When irradiated with an 808 nm laser, CS-NS liberated the entrapped EDTA, leading to Cu²⁺ chelation and subsequent disassembly of the core-satellite nanostructure. Photo-conversion from the large assembly to the small constituent particles proceeded within 5 min. Light-triggered CS-NS disassembly enhanced the carrier and cargo penetration and accumulation in tumor spheroids in vitro and in orthotopic murine mammary tumors in vivo. CS-NS is long circulating in the blood and conferred improved survival outcomes to tumor-bearing mice treated with light, compared to controls. These results demonstrate an MPN-integrated multistage nanosystem for improved solid tumor treatment.

In vivostudy of iron oxide-calcium phosphate composite nanoparticles for delivery to atherosclerosis

Atherosclerosis is a macrophage-related inflammatory disease that remains a leading cause of death worldwide. Magnetic iron oxide (IO) nanocrystals are clinically used as magnetic resonance imaging contrast agents and their application as a detection agent for macrophages in arterial lesions has been studied extensively. We recently fabricated heparin-modified calcium phosphate (CaP) nanoparticles loaded with a large number of IO nanocrystals via coprecipitation from a supersaturated CaP solution supplemented with heparin and ferucarbotran (IO nanocrystals coated with carboxydextran). In this study, we further increased the content of IO nanocrystals in the heparin-modified IO-CaP composite nanoparticles by increasing the ferucarbotran concentration in the supersaturated CaP solution. The increase in nanoparticle IO content caused a decrease in particle diameter without impairing its dispersibility; the nanoparticles remained dispersed in water for up to 2 h due to electrostatic repulsion between particles due to the surface modification with heparin. The nanoparticles were more effectively taken up by murine RAW264.7 macrophages compared to free ferucarbotran without showing significant cytotoxicity. A preliminaryin vivostudy showed that the nanoparticles injected intravenously into mice delivered more IO nanocrystals to macrophage-rich carotid arterial lesions than free ferucarbotran. Our nanoparticles have potential as a delivery agent of IO nanocrystals to macrophages in arterial lesions.

Nanostructured Dense Collagen-Polyester Composite Hydrogels as Amphiphilic Platforms for Drug Delivery

Associating collagen with biodegradable hydrophobic polyesters constitutes a promising method for the design of medicated biomaterials. Current collagen-polyester composite hydrogels consisting of pre-formed polymeric particles encapsulated within a low concentrated collagen hydrogel suffer from poor physical properties and low drug loading. Herein, an amphiphilic composite platform associating dense collagen hydrogels and up to 50 wt% polyesters with different hydrophobicity and chain length is developed. An original method of fabrication is disclosed based on in situ nanoprecipitation of polyesters impregnated in a pre-formed 3D dense collagen network. Composites made of poly(lactic-co-glycolic acid) (PLGA) and poly(lactic acid) (PLA) but not polycaprolactone (PCL) exhibit improved mechanical properties compared to those of pure collagen dense hydrogels while keeping a high degree of hydration. Release kinetics of spironolactone, a lipophilic steroid used as a drug model, can be tuned over one month. No cytotoxicity of the composites is observed on fibroblasts and keratinocytes. Unlike the incorporation of pre-formed particles, the new process allows for both improved physical properties of collagen hydrogels and controlled drug delivery. The ease of fabrication, wide range of accessible compositions, and positive preliminary safety evaluations of these collagen-polyesters will favor their translation into clinics in wide areas such as drug delivery and tissue engineering.

Enhanced intraperitoneal delivery of charged, aerosolized curcumin nanoparticles by electrostatic precipitation

Aims: To investigate the potential of curcumin-loaded polylactic-co-glycolic acid nanoparticles (CUR-PLGA-NPs), alone and with electrostatic precipitation, for improving tissue uptake during pressurized intraperitoneal aerosol chemotherapy (PIPAC). Methods: Positively and negatively charged CUR-PLGA-NPs were delivered as PIPAC into inverted bovine urinary bladders ex vivo. The experiment was repeated with the additional use of electrostatic precipitation pressurized intraperitoneal aerosol chemotherapy (electrostatic PIPAC). Results: Positively charged CUR-PLGA-NPs increased depth of tissue penetration by 81.5% and tissue concentration by 80%. Electrostatic precipitation further improved the uptake of positively charged CUR-PLGA-NPs by 41.8%. Conclusion: The combination of positive charge and electrostatic precipitation have significant potential to improve tissue uptake of nanoparticles during intraperitoneal chemotherapy.

l-Carnitine conjugated chitosan-stearic acid polymeric micelles for improving the oral bioavailability of paclitaxel

A delivery system based on l-carnitine (LC) conjugated chitosan (CS)-stearic acid polymeric micelles has been developed for improving the oral bioavailability of paclitaxel (PTX) through targeting intestinal organic cation/carnitine transporter 2 (OCTN2). Stearic acid grafted chitosan (CS-SA), as micelle skeleton material, was synthesized by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-mediated coupling reaction. The PTX-loaded micelles were prepared by solvent evaporation-hydration method, and the ligand LC was conjugated onto the micelle surface by anchoring its derivative stearoyl group to the lipophilic core of micelle. The modified polymeric micelles showed regular spherical shapes with small particle size of 157.1 ± 5.2 nm and high drug loading capacity of 15.96 ± 0.20 wt%, and the micelle stability in water was supported by low critical micelle concentration of 14.31 ± 0.21 μg/ml. The drug-loaded micelles presented a slow and incomplete in vitro release, and the pharmacokinetic studies indicated the micelle carriers increased the relative bioavailability of PTX to 165.8% against the commercial formulation. The enhancement effect on intestinal absorption was also confirmed by the intracellular uptake of Caco-2 cells. The proposed micelle carrier system manifested a prospective tool for oral drug delivery.

Enteric-Coated Strategies in Colorectal Cancer Nanoparticle Drug Delivery System

Colorectal cancer is one of the most common cancer diseases with the increase of cases prevalence >5% every year. Multidrug resistance mechanisms and non-localized therapy become primary problems of chemotherapy drugs for curing colorectal cancer disease. Therefore, the enteric-coated nanoparticle system has been studied and proved to be able to resolve those problems with good performance for colorectal cancer. The highlight of our review aims to summarize and discuss the enteric-coated nanoparticle drug delivery system specific for colorectal cancer disease. The main and supporting literatures were collected from published research articles of journals indexed in Scopus and PubMed databases. In the oral route of administration, Eudragit pH-sensitive copolymer as a coating agent prevents the degradation of the nanoparticle system from the gastric fluid and releases drug to intestinal-colon track. Therefore, it provides a colon-specific targeting ability. Impressively, enteric-coated nanoparticles having a sustained release profile significantly increase the cytotoxic effect of chemotherapeutic drugs and achieve cell-specific target delivery. The enteric-coated nanoparticle drug delivery system represents an excellent modification to improve the effectiveness and performance of anticancer drugs for colorectal cancer disease in terms of the oral route of administration.

Design and evaluation of the anticancer activity of paclitaxel-loaded anisotropic-poly(lactic-co-glycolic acid) nanoparticles with PEGylated chitosan surface modifications

This study aimed to evaluate the anticancer activity of paclitaxel-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (PNPs) based on their shapes and surface modifications in breast cancer cells. We hypothesized that anisotropic-PNPs (AT-PNPs) with PEGylated chitosan (CP) surface modifications and high aspect ratios exhibit higher anticancer activity than PNPs and AT-PNPs with CP surface modifications and low aspect ratios. Six types of PNPs and AT-PNPs with different shapes and surface modifications were successfully prepared. The cellular uptake and cytotoxicity of the AT-PNPs were higher than those of the PNPs, while the cellular uptake and cytotoxicity of the PNPs and AT-PNPs with CP were higher than those of the uncoated PNPs and AT-PNPs. Moreover, all the particles remained stable for 4 months. In conclusion, this study primarily described the preparation of CP-AT-PNPs, and the CP-AT-PNPs2 developed herein are expected to demonstrate promising anticancer effects in animal experiments and clinical studies.

Neutrophils, as "Trojan horses", participate in the delivery of therapeutical PLGA nanoparticles into a tumor based on the chemotactic effect

Inspired by the fact that leukocytes have innate phagocytic functions and oriented migration capabilities in response to chemoattractants, we have unveiled that endogenous neutrophils as “Trojan horses”, participate in the delivery of nanoparticles in an “in vivo self-armed assembly” manner. Neutrophils were the main population to preferentially sequester the intravenous administrated nanoparticles with an average size of 260 nm. The pre-implantation of CXCL1-laden hydrogels could trigger and induce a targeted signal to attract an influx of neutrophils carrying the therapeutic goods to the desired position. In mouse models of melanoma, the combinatorial regimen of using the PLGA nanoparticles with the CXCL1 hydrogels exhibited superior tumor inhibition capability. This work leveraged the natural phagocytosis of neutrophile and the chemotactic effect of chemokines for targeted delivery. We believe this strategy will improve the therapeutic efficiency of nanoparticle-based delivery systems, especially when the chemokines are implanted at sites of surgical tumor removal, during cancer treatment at the clinic.

Influence of Hydrophobic Chains in Nanocarriers on Antitumor Efficacy of Docetaxel Nanoparticles

The composition of amphiphilic nanocarriers can affect the antitumor efficacy of drug-loaded nanoparticles and should be researched systematically. In this paper, to study the influence of hydrophobic chains, an amphiphilic copolymer (PEG₄₅PCL₁₇) and hydrophilic PEG (PEG₄₅) were utilized as nanocarriers to prepare docetaxel-loaded nanoparticles (DTX/PEG₄₅PCL₁₇ nanoparticles and DTX/PEG₄₅ nanoparticles) through an antisolvent precipitation method. The two DTX nanoparticles presented a similar drug loading content of approximately 60% and a sheet-like morphology. During the preparation procedure, the drug loading content affected the morphology of DTX nanoparticles, and the nanocarrier composition influenced the particle size. Compared with DTX/PEG₄₅ nanoparticles, DTX/PEG₄₅PCL₁₇ nanoparticles showed a smaller mean diameter and better in vitro and in vivo antitumor activity. The cytotoxicity of DTX/PEG₄₅PCL₁₇ nanoparticles against 4T1 cells was 1.31 μg mL^-1, 3.4-fold lower than that of DTX/PEG₄₅ nanoparticles. More importantly, DTX/PEG₄₅PCL₁₇ nanoparticles showed significantly higher antitumor activity in vivo, with an inhibition rate over 80%, 1.5-fold higher than that of DTX/PEG₄₅ nanoparticles. Based on these results, antitumor activity appears to be significantly affected by the particle size, which was determined by the composition of the nanocarrier. In summary, to improve antitumor efficacy, the amphiphilic structure should be considered and optimized in the design of nanocarriers.

Synergistic Mechanisms of Constituents in Herbal Extracts during Intestinal Absorption: Focus on Natural Occurring Nanoparticles

The systematic separation strategy has long and widely been applied in the research and development of herbal medicines. However, the pharmacological effects of many bioactive constituents are much weaker than those of the corresponding herbal extracts. Thus, there is a consensus that purer herbal extracts are sometimes less effective. Pharmacological loss of purified constituents is closely associated with their significantly reduced intestinal absorption after oral administration. In this review, pharmacokinetic synergies among constituents in herbal extracts during intestinal absorption were systematically summarized to broaden the general understanding of the pharmaceutical nature of herbal medicines. Briefly, some coexisting constituents including plant-produced primary and secondary metabolites, promote the intestinal absorption of active constituents by improving solubility, inhibiting first-pass elimination mediated by drug-metabolizing enzymes or drug transporters, increasing the membrane permeability of enterocytes, and reversibly opening the paracellular tight junction between enterocytes. Moreover, some coexisting constituents change the forms of bioactive constituents via mechanisms including the formation of natural nanoparticles. This review will focus on explaining this new synergistic mechanism. Thus, herbal extracts can be considered mixtures of bioactive compounds and pharmacokinetic synergists. This review may provide ideas and strategies for further research and development of herbal medicines.

Tunable Decoupling of Dual Drug Release of Oppositely Charged, Stimuli-Responsive Anisotropic Nanoparticles

Multicompartmentalized nanostructures are of interest because they can provide unique physicochemical properties and multifunctionalities in each compartment. Furthermore, stimuli-responsive anisotropic nanostructures (ANPs) with distinct opposite charges would be useful for drug delivery systems because different drug release kinetics could be achieved from each compartment in response to both charge and stimuli. In this study, stimuli-responsive ANPs were formed via electrohydrodynamic cojetting of poly(N-isopropylacrylamide)-based copolymers with opposite charges. The positively charged compartment consisted of poly(N-isopropylacylamide-co-stearyl acrylate-co-allylamine) (poly(NIPAM-co-SA-co-AAm)) (i.e., PNSAAm) and poly(N-isopropylacylamide-co-stearyl acrylate-co-acrylic acid) (poly(NIPAM-co-SA-co-AAc)) (i.e., PNSAAc). The two distinct compartments of ANPs were physically cross-linked through hydrophobic interactions within the copolymers. Oppositely charged, small-molecule model drugs (fluorescein sodium salt and rhodamine 6G) were separately encapsulated within each compartment and released based on changes in noncovalent interactions and temperature. Furthermore, two different biomacromolecule drugs with opposite charges, bovine serum albumin and lysozyme (which were complexed with polysaccharides by hydrophobic ion pairing), were loaded within the ANPs. Electrostatic interactions between the encapsulated drugs and each ANP compartment controlled the rate of drug release from the ANPs. In addition, these ANPs showed a thermally induced actuation, leading to drug release at different rates due to the collapse of poly(NIPAM)-based copolymers under aqueous conditions. This work may be useful for decoupled drug release kinetics.

Starch-regulated copper-terephthalic acid as a pH/hydrogen peroxide simultaneous-responsive fluorescent probe for lysosome imaging

Lysosome visualization is very important for accurate diagnosis of human diseases. However, currently developed lysosome imaging probes usually have poor specificity and are easily quenched, leading to a low signal to noise ratio in lysosome labeling. To resolve this problem, herein, metal-organic framework-based probes of copper-terephthalic acid (CuBDC) are investigated, which show sensitivity to pH and hydrogen peroxide (H₂O₂), simultaneously. By self-assembling under the template effect of soluble starch, the particle size of CuBDC can be well controlled for entering into cells and locating lysosomes. Based on the Fenton-like reaction, CuBDC can catalyze the decomposition of H₂O₂ into ˙OH, which in turn reacts with CuBDC to generate a stable fluorescent substance. Meanwhile, Cu²⁺ can be released from CuBDC under acidic conditions for reacting with H₂O₂ more thoroughly. And the synthesized CuBDC has a similar attraction to the electrophilic ˙OH at different pH values owing to the residual soluble starch in the particles. The above properties cause CuBDC to have a stable fluorescence signal with low pH values and high H₂O₂ concentration, simultaneously. The fluorescence imaging experiments in HeLa cells demonstrate that CuBDC acting as a pH/H₂O₂ responsive fluorescent probe holds great promise for lysosome-specific imaging.

Nanoformulations for glioblastoma multiforme: a new hope for treatment

Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor in adults, associated with a high mortality rate and a survival of between 12 and 15 months after diagnosis. Due to current treatment limitations involving surgery, radiotherapy and chemotherapy with temozolamide, there is a high rate of treatment failure and recurrence. To try to overcome these limitations nanotechnology has emerged as a novel alternative. Lipid, polymeric, silica and magnetic nanoparticles, among others, are being developed to improve GBM treatment and diagnosis. These nanoformulations have many advantages, including lower toxicity, biocompatibility and the ability to be directed toward the tumor. This article reviews the progress that have been made and the large variety of nanoparticles currently under study for GBM.

The size and composition of polymeric nanocapsules dictate their interaction with macrophages and biodistribution in zebrafish

Macrophages are pivotal cells of the innate immune system specialized in the phagocytosis of foreign elements. Nanoparticles intentionally designed to target macrophages and modulate their response are of especial interest in the case of chronic inflammatory diseases, cancer and for vaccine development. This work aimed to understand the role of size and shell composition of polymeric nanocapsules (NCs) in their interaction with macrophages, both in vitro and in vivo. A systematic study was performed using two different sizes of inulin and chitosan NCs, negatively and positively charged, respectively, small (≈ 70 nm) and medium (170-250 nm). The in vitro results showed that small NCs interacted more efficiently with macrophages than their larger counterparts. Inulin NCs were significantly less toxic than chitosan NCs. Finally, following in vivo administration (intravenous/intramuscular) to zebrafish, small NCs, regardless of their composition, disseminated considerably faster and further than their medium size counterparts. These results emphasize how small changes in the nanometric range can lead to a remarkably different interaction with the immune cells and biodistribution profile.

Bacteria-Targeted Clindamycin Loaded Polymeric Nanoparticles: Effect of Surface Charge on Nanoparticle Adhesion to MRSA, Antibacterial Activity, and Wound Healing

Adhesion of nanoparticles (NPs) to the bacterial cell wall by modifying their physicochemical properties can improve the antibacterial activity of antibiotic. In this study, we prepared positively charged clindamycin-loaded poly (lactic-co-glycolic acid)-polyethylenimine (PLGA-PEI) nanoparticles (Cly/PPNPs) and negatively charged clindamycin-loaded PLGA NPs (Cly/PNPs) and investigated the effect of NP adhesion to bacteria on the treatment of methicillin-resistant Staphylococcus aureus (MRSA)-infected wounds. The Cly/PPNPs and Cly/PNPs were characterized according to particle size, polydispersity index, surface charge, and drug loading. Both Cly/PPNPs and Cly/PNPs exhibited sustained drug release over 2 days. The Cly/PPNPs bind to the MRSA surface, thereby enhancing bactericidal efficacy against MRSA compared with the Cly/PNPs. Furthermore, compared with other groups, Cly/PPNPs significantly accelerated the healing and re-epithelialization of wounds in a mouse model of a MRSA-infected wounds. We also found that both NPs are harmless to healthy fibroblast cells. Therefore, our results suggest that the Cly/PPNPs developed in this study improve the efficacy of clindamycin for the treatment of MRSA-infected wounds.

Biocompatibility Profile and In Vitro Cellular Uptake of Self-assembled Alginate Nanoparticles

Polymeric nanoparticles could offer promising controlled drug delivery. The biocompatibility is of extreme importance for future applications in humans. Self-assembled polymeric nanoparticles based on phenylalanine ethyl ester (PAE)-modified alginate (Alg) had been successfully prepared and characterized in our lab. However, little is known about their interaction with cells and other biological systems. In this study, nanoparticles (NPs) based on PAE-Alg conjugates (PEA-NPs) with different degree of substitution (DS) were prepared and investigated. Our results showed that PEA-NPs had no effects on the proliferation of the human intestinal epithelial Caco-2 cells at concentrations up to 1000 μg/mL. Furthermore, the in vitro cellular uptake profile of PEA-NPs, concerning several parameters involved in the application of therapeutic or diagnostic NPs, such as NPs concentration, time and temperature, was described. Different NPs have been adopted for cellular uptake studies and the NPs internalized into Caco-2 cells were quantified. Cellular uptake efficiency could reach 60% within 4 h. PEA-NPs also showed greater cell permeability than oleoyl alginate ester nanoparticles (OAE-NPs) previously prepared in our lab. Our studies reveal that NPs based on PEA conjugate are promising nanosystems for cellular delivery.

Development of PLGA micro- and nanorods with high capacity of surface ligand conjugation for enhanced targeted delivery

Particle shape has been recognized as one of the key properties of nanoparticles in biomedical applications including targeted drug delivery. Targeting ability of shape-engineered particles depends largely on targeting ligands conjugated on the particle surface. However, poor capacity for surface ligand conjugation remains a problem in anisotropic nanoparticles made with biodegradable polymers such as PLGA. In this study, we prepared anisotropic PLGA nanoparticles with abundant conjugatable surface functional groups by a film stretching-based fabrication method with poly (ethylene-alt-maleic acid) (PEMA). Scanning electron microscopy images showed that microrods and nanorods were successfully fabricated by the PEMA-based film stretching method. The presence of surface carboxylic acid groups was confirmed by confocal microscopy and zeta potential measurements. Using the improved film-stretching method, the amount of protein conjugated to the surface of nanorods was increased three-fold. Transferrin-conjugated, nanorods fabricated by the improved method exhibited higher binding and internalization than unmodified counterparts. Therefore, the PEMA-based film-stretching system presented in this study would be a promising fabrication method for non-spherical biodegradable polymeric micro- and nanoparticles with high capacity of surface modifications for enhanced targeted delivery.

Co-delivery doxorubicin and silybin for anti-hepatoma via enhanced oral hepatic-targeted efficiency

Background

To establish the combination of doxorubicin (DOX) and silybin (SLB) in oral hepatic-targeting liposomes with the goal of reducing cardiotoxic side effects and improve oral hepatoma treatment.

Methods

Distearoylphosphatidylethanolamine–polyethylene glycol–cholic acid-modified liposomes (CA-LP) were used to encapsulate DOX and SLB (CA-LP–DOX/SLB), and the hepatic targeting, efficacy against hepatoma and cardioprotective effects were evaluated by cell toxicity, scratch and apoptosis in vitro studies, and pharmacokinetics and pharmacodynamics in vivo studies.

Results

In vitro cell studies showed that CA-LP–DOX/SLB inhibited HepG2 cell proliferation and HCC97H cell migration, and protected H9c2 cells. In vivo pharmacokinetics demonstrated that the CA-LP–DOX/SLB-treated group showed higher liver accumulation and lower heart accumulation of DOX relative to those in the CA-LP–DOX and LP–DOX-treated groups. In vivo pharmacodynamic studies showed that the CA-LP–DOX/SLB-treated group not only efficiently inhibited growth but also induced significantly less tissue damage than that observed in the CA-LP–DOX-treated group.

Conclusion

Concurrent administration of DOX and SLB via CA-LP provided a viable strategy to mitigate acute DOX-induced cardiotoxicity.

Doxorubicin and indocyanine green loaded superparamagnetic iron oxide nanoparticles with PEGylated phospholipid coating for magnetic resonance with fluorescence imaging and chemotherapy of glioma

Background

Glioma represents the most common malignant brain tumor. Outcomes of surgical resection are often unsatisfactory due to low sensitivity or resolution of imaging methods. Moreover, the use of traditional chemotherapeutics, such as doxorubicin (DOX), is limited due to their low blood-brain barrier (BBB) permeability. Recently, the development of nanotechnology could overcome these obstacles.

Materials and methods

Hydrophobic superparamagnetic iron oxide nanoparticles (SPIO NPs) were prepared with the use of thermal decomposition method. They were coated with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG 2000) and DOX using a thin-film hydration method followed by loading of indocyanine green (ICG) into the phospholipid layers. Details regarding the characteristics of NPs were determined. The in vitro biocompatibility and antitumor efficacy were established with the use of MTT assay. In vivo fluorescence and magnetic resonance (MR) imaging were used to evaluate BBB penetration and accumulation of NPs at the tumor site. Antitumor efficacy was evaluated using measures of tumor size, median survival times, body weights, and H&E staining.

Results

The multifunctional NPs generated had an average diameter of 22.9 nm, a zeta potential of -38.19 mV, and were capable of providing a sustained release of DOX. In vitro experiments demonstrated that the SPIO@DSPE-PEG/DOX/ICG NPs effectively enhanced cellular uptake of DOX as compared with that of free DOX. In vivo fluorescence and MR imaging revealed that the NPs not only effectively crossed the BBB but selectively accumulated at the tumor site. Meanwhile, among all groups studied, C6 glioma-bearing rats treated with the NPs exhibited the maximal degree of therapeutic efficacy, including smallest tumor volume, lowest body weight loss, and longest survival times, with no obvious side effects.

Conclusion

These results suggest that the SPIO@DSPE-PEG/DOX/ICG NPs can not only function as a nanoprobe for MR and fluorescence bimodal imaging, but also as a vehicle to deliver chemotherapeutic drugs to the tumor site, to achieve the theranostic treatment of glioma.

ATP-Responsive Low-Molecular-Weight Polyethylenimine-Based Supramolecular Assembly via Host-Guest Interaction for Gene Delivery

In this work, we report on an ATP-responsive low-molecular-weight polyethylenimine (LMW-PEI)-based supramolecular assembly. It formed via host-guest interaction between PEI (MW = 1.8 kDa)-α-cyclodextrin (α-CD) conjugates and PEI_1.8k-phenylboronic acid (PBA) conjugates. The host-guest interaction between PEI_1.8k-α-CD and PEI_1.8k-PBA was confirmed by the 2D-NOESY chromatogram experiment and competition test. The ATP-responsive property of the supramolecular assembly was evaluated by a series of ATP-triggered degradation and siRNA release studies in terms of fluorescence resonance energy transfer, agarose gel electrophoresis assay, and the time course monitoring of the particle size and morphology. Confocal laser scanning microscopy confirmed the intracellular disassembly of the supramolecular polymer and the release of siRNA. The supramolecular assembly showed high buffering capability and was capable of protecting siRNA from RNase degradation. It had high cytocompatibility according to in vitro cytotoxicity and hemolysis assays. LMW-PEI-based supramolecular assembly facilitated cellular entry of siRNA via energy-dependent endocytosis. Moreover, the assembly/SR-A siRNA polyplexes at N/P ratio of 30 was most effective in knocking down SR-A mRNA and inhibiting uptake of modified LDL. Taken together, this work shows that ATP-responsive LMW-PEI-based supramolecular assembly is a promising gene vector and has potential application in treating atherosclerosis.

Sialic Acid-Functionalized PEG-PLGA Microspheres Loading Mitochondrial-Targeting-Modified Curcumin for Acute Lung Injury Therapy

Acute lung injury (ALI) is a serious illness without resultful therapeutic methods commonly. Recent studies indicate the importance of oxidative stress in the occurrence and development of ALI, and mitochondria targeted antioxidant has become a difficult and hot topic in the research of ALI. Therefore, a sialic acid (SA)-modified lung-targeted microsphere (MS) for ALI therapy are developed, with triphenylphosphonium cation (TPP)-modified curcumin (Cur-TPP) loaded, which could specifically target the mitochondria, increasing the effect of antioxidant. The results manifest that with the increase of microsphere, lung distribution of microsphere is also increased in murine mice, and after SA modification, the microsphere exhibits the ideal lung-targeted characteristic in ALI model mice, due to SA efficiently targeting to E-selectin expressed on inflammatory tissues. Further investigations indicate that SA/Cur-TPP/MS has better antioxidative capacity, decreases intracellular ROS generation, and increases mitochondrial membrane potential, contributing to a lower apoptosis rate in human umbilical vein endothelial cells (HUVECs) compared to H₂O₂ group. In vivo efficacy of SA/Cur-TPP/MS demonstrates that the inflammation has been alleviated markedly and the oxidative stress is ameliorated efficiently. Significant histological improvements by SA/Cur-TPP/MS are further proved via HE stains. In conclusion, SA/Cur-TPP/MS might act as a promising drug formulation for ALI therapy.

Intratumoral injection of gels containing losartan microspheres and (PLG-g-mPEG)-cisplatin nanoparticles improves drug penetration, retention and anti-tumor activity

Intratumoral injection of chemotherapy agents may be employed in the treatment of cancers. However, its anti-tumor efficacy is significantly impeded by collagen fibers in the tumor which decrease drug penetration into the tumor tissues. To improve the penetration, collagen inhibiting drug exposure is required. In this study, microspheres were fabricated by the modified double emulsion-solvent evaporation method as the drug delivery system of losartan potassium (LP MSs), with 5% gelatin as the inner phase. The collagen inhibiting experiment analyzed by Sirius Red stains demonstrated that LP MSs may effectively inhibit collagen I synthesis in B16 tumors. In addition, 15% F127 was used as the solvent to fix the formulations at the injection site, with poly (α-l-glutamate) grafted polyethylene glycol mono methyl ether (PLG-g-mPEG)-cisplatin loaded nanoparticles (CDDP NPs) as the model drug. The in vivo live imaging system showed that formulations dissolved in 15% F127 had 54.91% CDDP NPs retained in tumors at the end of 10 days, in comparison with 19.72% for those solved in water, suggesting strong intratumoral retention property of the in situ gel. In addition, confocal laser scanning microscope (CLSM) and Energy-Dispersive Analysis of X-ray spectroscopy combined with scanning electron microscope (SEM-EDAX) tests showed that LP MSs can effectively enhance the distribution and penetration of CDDP NPs within tumors. Furthermore, tumors i.t. treated with LP MSs/CDDP NPs gel could be significantly halted, or even reduced to 200 mm³, comparing with a volume of about 12000 mm³ incontrol group at the end of the anti-tumor effect experiment. These results provided important guiding principles for prolonged and localized drug delivery system of intratumoral collagen inhibitor. The improvements of intratumoral penetration method made in this study provided practical significance for the treatment of cancer, especially for mass tumors.

3,3'-Diindolylmethane Encapsulated Chitosan Nanoparticles Accelerates Inflammatory Markers, ER/PR, Glycoprotein and Mast Cells Population During Chemical Carcinogen Induced Mammary Cancer in Rats

The present study aimed to investigate the effect of 3,3'-diindolylmethane (DIM) on inflammatory markers, estrogen receptors (ER), progesterone receptors (PR), level of glycoprotein and the mast cell population in 7,12-dimethylbenz (a) anthracene (DMBA) 25 mg/kg b.wt. induced rat mammary carcinogenesis. After 8 weeks of tumor formation, rats had access to an oral administrated with DIM 10 mg/kg b.wt. and DIM@CS-NP 0.5 mg/kg body weight respectively for 8 weeks. The oral administration of DIM@CS-NP 0.5 mg/kg b.wt. suppressed the Cox-2, NF-κB and TNF-α protein expression on DMBA induced rats compared to DIM 10 mg/kg b.wt. The ER/PR levels were increased on DMBA induced rats, treated with DIM@CS-NP 0.5 mg/kg b.wt. reduced ER/PR level as well as glycoprotein and mast cell population than DIM 10 mg/kg b.wt. The result shows that, DIM@CS-NP 0.5 mg/kg b.wt. has the potentially inhibit abnormal levels of inflammatory markers, ER, PR, levels of glycoprotein and mast cell population compared to DIM 10 mg/kg b.wt.