Surface functionalization of PLGA nanoparticles by non-covalent insertion of a homo-bifunctional spacer for active targeting in cancer therapy

Advancements in curcumin-loaded PLGA nanoparticle delivery systems: progressive strategies in cancer therapy

Cancer is a leading cause of death worldwide, and imposes a substantial socioeconomic burden with little impact especially on aggressive types of cancer. Conventional therapies have many serious side effects including generalised systemic toxicity which limits their long-term use. Tumour resistance and recurrence is another main problem associated with conventional therapy. Purified or extracted natural products have been investigated as cost-effective cancer chemoprotective agents with the potential to reverse or delaying carcinogenesis. Curcumin (CUR) as a natural polyphenolic component, exhibits many pharmacological activities such as anti-cancer, anti-inflammatory, anti-microbial, activity against neurodegenerative diseases including Alzheimer, antidiabetic activities (type II diabetes), anticoagulant properties, wound healing effects in both preclinical and clinical studies. Despite these effective protective properties, CUR has several limitations, including poor aqueous solubility, low bioavailability, chemical instability, rapid metabolism and a short half-life time. To overcome the pharmaceutical problems associated with free CUR, novel nanomedicine strategies (including polymeric nanoparticles (NPs) such as poly (lactic-co-glycolic acid) (PLGA) NPs have been developed. These formulations have the potential to improve the therapeutic efficacy of curcuminoids. In this review, we comprehensively summarise and discuss recent in vitro and in vivo studies to explore the pharmaceutical significance and clinical benefits of PLGA-NPs delivery system to improve the efficacy of CUR in the treatment of cancer.

Facile synthesis of elastin nanogels encapsulated decursin for castrated resistance prostate cancer therapy

Nanogels offer hope for precise drug delivery, while addressing drug delivery hurdles is vital for effective prostate cancer (PCa) management. We developed an injectable elastin nanogels (ENG) for efficient drug delivery system to overcome castration-resistant prostate cancer (CRPC) by delivering Decursin, a small molecule inhibitor that blocks Wnt/βcatenin pathways for PCa. The ENG exhibited favourable characteristics such as biocompatibility, flexibility, and low toxicity. In this study, size, shape, surface charge, chemical composition, thermal stability, and other properties of ENG were used to confirm the successful synthesis and incorporation of Decursin (DEC) into elastin nanogels (ENG) for prostate cancer therapy. In vitro studies demonstrated sustained release of DEC from the ENG over 120 h, with a pH-dependent release pattern. DU145 cell line induces moderate cytotoxicity of DEC-ENG indicates that nanomedicine has an impact on cell viability and helps strike a balance between therapeutics efficacy and safety while the EPR effect enables targeted drug delivery to prostate tumor sites compared to free DEC. Morphological analysis further supported the effectiveness of DEC-ENG in inducing cell death. Overall, these findings highlight the promising role of ENG-encapsulated decursin as a targeted drug delivery system for CRPC.

Polymeric Nanoparticles for Delivery of Natural Bioactive Agents: Recent Advances and Challenges

In the last few decades, several natural bioactive agents have been widely utilized in the treatment and prevention of many diseases owing to their unique and versatile therapeutic effects, including antioxidant, anti-inflammatory, anticancer, and neuroprotective action. However, their poor aqueous solubility, poor bioavailability, low GIT stability, extensive metabolism as well as short duration of action are the most shortfalls hampering their biomedical/pharmaceutical applications. Different drug delivery platforms have developed in this regard, and a captivating tool of this has been the fabrication of nanocarriers. In particular, polymeric nanoparticles were reported to offer proficient delivery of various natural bioactive agents with good entrapment potential and stability, an efficiently controlled release, improved bioavailability, and fascinating therapeutic efficacy. In addition, surface decoration and polymer functionalization have opened the door to improving the characteristics of polymeric nanoparticles and alleviating the reported toxicity. Herein, a review of the state of knowledge on polymeric nanoparticles loaded with natural bioactive agents is presented. The review focuses on frequently used polymeric materials and their corresponding methods of fabrication, the needs of such systems for natural bioactive agents, polymeric nanoparticles loaded with natural bioactive agents in the literature, and the potential role of polymer functionalization, hybrid systems, and stimuli-responsive systems in overcoming most of the system drawbacks. This exploration may offer a thorough idea of viewing the polymeric nanoparticles as a potential candidate for the delivery of natural bioactive agents as well as the challenges and the combating tools used to overcome any hurdles.

Surface Engineering of Nanomaterials with Polymers, Biomolecules, and Small Ligands for Nanomedicine

Nanomedicine is a speedily growing area of medical research that is focused on developing nanomaterials for the prevention, diagnosis, and treatment of diseases. Nanomaterials with unique physicochemical properties have recently attracted a lot of attention since they offer a lot of potential in biomedical research. Novel generations of engineered nanostructures, also known as designed and functionalized nanomaterials, have opened up new possibilities in the applications of biomedical approaches such as biological imaging, biomolecular sensing, medical devices, drug delivery, and therapy. Polymers, natural biomolecules, or synthetic ligands can interact physically or chemically with nanomaterials to functionalize them for targeted uses. This paper reviews current research in nanotechnology, with a focus on nanomaterial functionalization for medical applications. Firstly, a brief overview of the different types of nanomaterials and the strategies for their surface functionalization is offered. Secondly, different types of functionalized nanomaterials are reviewed. Then, their potential cytotoxicity and cost-effectiveness are discussed. Finally, their use in diverse fields is examined in detail, including cancer treatment, tissue engineering, drug/gene delivery, and medical implants.

Naringin as Sustained Delivery Nanoparticles Ameliorates the Anti-inflammatory Activity in a Freund's Complete Adjuvant-Induced Arthritis Model

Naringin (NAR), a naturally occurring essential flavonoid, present in grapefruit and Chinese herbal medicines, creates great interest in researchers due to its diverse biological and pharmacological activities. However, further development of NAR is hindered due to its poor water solubility and dissolution rates in GIT. To address these limitations, in this study, we report polymeric nanoparticles (NPs) of NAR (NAR-PLGA-NPs) for enhancing the oral NAR efficiency, with a biodegradable polymer (PLGA) to improve its absorption and bioavailability. NAR-PLGA-NPs were fabricated by a modified solvent emulsification-evaporation technique. Physicochemical properties were evaluated by SEM, particle size distribution, entrapment efficiency, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). In vitro drug release and ex vivo permeation studies were carried out in phosphate buffer (pH 6.8) for 24 h. Furthermore, in vivo anti-arthritic studies were performed on a mouse model, and the results were compared with free NAR. The modulation of inflammatory mediators was also evidently supported by docking studies. Optimized nanoformulation FN4 (NAR-PLGA-NPs) prepared with acetone-ethanol (2:1) as a solvent system in a combination of stabilizers, i.e., poloxamer-188 and sodium deoxylate (1:1), along with 2% PVA solution, was prepared. From size characterization studies, it was observed that nanoformulations possessed a low particle size (179.7 ± 2.05 nm), a low polydispersity index (0.206 ± 0.001), and a negative zeta potential (-9.18 ± 0.78 mV) with a maximum entrapment efficiency (74 ± 3.61%). The drug release followed a Korsmeyer-Peppas release kinetic model (anomalous non-Fickian diffusion), providing greater NAR release after lyophilization (82.11 ± 3.65%) drug release in pH 6.8 phosphate buffer for 24 h. Ex vivo permeation analysis through an isolated goat intestinal membrane revealed 80.02 ± 3.69% drug release in 24 h. Encapsulation of a drug into PLGA is well described by the results of FTIR, DSC, and XRD. Finally, the therapeutic efficacy of optimized FN4 (NAR-PLGA-NPs) and its possible application on RA were further confirmed in a Freund's complete adjuvant-induced rat arthritic model as against free NAR at a dose of 20 mg/kg body wt. Our findings demonstrate that sustained action of NAR from optimized FN4 NPs with a rate-controlling polymeric carrier system exhibited prolonged circulation time and reduced arthritic inflammation, hence indicating the possibility as a novel strategy to secure the unpropitious biological interactions of hydrophobic NAR in a gastric environment.

Role of Phytonutrients in Nutrigenetics and Nutrigenomics Perspective in Curing Breast Cancer

Breast cancer (BC) is one of the most common type of cancer and an important contributor to female mortality. Several genes and epigenetic modifications are involved in the development and progression of BC. Research in phytochemistry, nutrigenomics, and nutrigenetics has provided strong evidence that certain phytonutrients are able to modulate gene expression at transcriptional and post-transcriptional levels. Such phytonutrients may also be beneficial to prevent and treat BC. In this review, we will focus on the nutrigenomic effects of various phytochemicals including polyphenols, phytosterols, terpenoids, alkaloids, and other compounds from different sources. Overall, these phytonutrients are found to inhibit BC cell proliferation, differentiation, invasion, metastasis, angiogenesis, and induce apoptotic cell death by targeting various molecular pathways. They also alter epigenetic mechanisms and enhance the chemosensitivity and radiosensitivity of cancer cells. Such phytochemicals may be used for the effective management of BC patients in the clinical setting in the future. The present article aims to summarize the specific molecular pathways involved in the genetic effects of phytochemicals in BC.

Nose-to-brain co-delivery of drugs for glioblastoma treatment using nanostructured system

Mutations on the epidermal growth factor receptor (EGFR), induction of angiogenesis, and reprogramming cellular energetics are all biological features acquired by tumor cells during tumor development, and also known as the hallmarks of cancer. Targeted therapies that combine drugs that are capable of acting against such concepts are of great interest, since they can potentially improve the therapeutic efficacy of treatments of complex pathologies, such as glioblastoma (GBM). However, the anatomical location and biological behavior of this neoplasm imposes great challenges for targeted therapies. A novel strategy that combines alpha-cyano-4-hydroxycinnamic acid (CHC) with the monoclonal antibody cetuximab (CTX), both carried onto a nanotechnology-based delivery system, is herein proposed for GBM treatment via nose-to-brain delivery. The biological performance of Poly (D,L-lactic-co-glycolic acid)/chitosan nanoparticles (NP), loaded with CHC, and conjugated with CTX by covalent bonds (conjugated NP) were extensively investigated. The NP platforms were able to control CHC release, indicating that drug release was driven by the Weibull model. An ex vivo study with nasal porcine mucosa demonstrated the capability of these systems to promote CHC and CTX permeation. Blot analysis confirmed that CTX, covalently associated to NP, impairs EGRF activation. The chicken chorioallantoic membrane assay demonstrated a trend of tumor reduction when conjugated NP were employed. Finally, images acquired by fluorescence tomography evidenced that the developed nanoplatform was effective in enabling nose-to-brain transport upon nasal administration. In conclusion, the developed delivery system exhibited suitability as an effective novel co-delivery approaches for GBM treatment upon intranasal administration.

Ligand decorated biodegradable nanomedicine in the treatment of cancer

Cancer is one of the major global health problems, responsible for the second-highest number of deaths. The genetic and epigenetic changes in the oncogenes or tumor suppressor genes alter the regulatory pathways leading to its onset and progression. Conventional methods are used in appropriate combinations for the treatment. Surgery effectively treats localized tumors; however, it fails to treat metastatic tumors, leading to a spread in other organs, causing a high recurrence rate and death. Among the different strategies, the nanocarriers-based approach is highly sought for, but its nonspecific delivery can cause a profound side effect on healthy cells. Targeted nanomedicine has the advantage of targeting cancer cells specifically by interacting with the receptors overexpressed on their surface, overcoming its non-specificity to target healthy cells. Nanocarriers prepared from biodegradable and biocompatible materials are decorated with different ligands by encapsulating therapeutic or diagnostic agents or both to target cancer cells overexpressing the receptors. Scientists are now utilizing a theranostic approach to simultaneously evaluate nanocarrier bio-distribution and its effect on the treatment regime. Herein, we have summarized the recent 5-year efforts in the development of the ligands decorated biodegradable nanocarriers, as a targeted nanomedicine approach, which has been highly promising in the treatment of cancer.

CD-340 functionalized doxorubicin-loaded nanoparticle induces apoptosis and reduces tumor volume along with drug-related cardiotoxicity in mice

Background and objective

Targeted drug delivery of nanoparticles decorated with site-specific recognition ligands is of considerable interest to minimize cytotoxicity of chemotherapeutics in the normal cells. The study was designed to develop CD-340 antibody-conjugated polylactic-co-glycolic acid (PLGA) nanoparticles loaded with a highly water-soluble potent anticancer drug, doxorubicin (DOX), to specifically deliver entrapped DOX to breast cancer cells.

Methods

The study showed how to incorporate water-soluble drug in a hydrophobic PLGA (85:15) based matrix which otherwise shows poor drug loading due to leaching effect. The optimized formulation was covalently conjugated to anti-human epidermal growth factor receptor-2 (HER2) antibody (CD-340). Surface conjugation of the ligand was assessed by flow cytometry, confocal microscopy, and gel electrophoresis. Selectivity and cytotoxicity of the experimental nanoparticles were tested on human breast cancer cells SKBR-3, MCF-7, and MDA-MB-231. Both CD-340-conjugated and unconjugated nanoparticles were undergone in vitro and in vivo characterization.

Result

Higher level of incorporation of DOX (8.5% W/W), which otherwise shows poor drug loading due to leaching effect of the highly water-soluble drug, was seen in this method. In HER2-overexpressing tumor xenograft model, radiolabeled antibody-conjugated nanoparticles showed preferentially more of the formulation accumulation in the tumor area when compared to the treatments with the unconjugated one or with the other control groups of mice. The ligand conjugated nanoparticles showed considerable potential in reduction of tumor growth and cardiac toxicity of DOX in mice, a prominent side-effect of the drug.

Conclusion

In conclusion, CD-340-conjugated PLGA nanoparticles containing DOX preferentially delivered encapsulated drug to the breast cancer cells and in breast tumor and reduced the breast tumor cells by apoptosis. Site-specific delivery of the formulation to neoplastic cells did not affect normal cells and showed a drastic reduction of DOX-related cardiotoxicity.

Application of active targeting nanoparticle delivery system for chemotherapeutic drugs and traditional/herbal medicines in cancer therapy: a systematic review

Patients treated with conventional cancer chemotherapy suffer from side effects of the drugs due to non-selective action of chemotherapeutic drugs to normal cells. Active targeting nanoparticles that are conjugated to targeting ligands on the surface of nanoparticles play an important role in improving drug selectivity to the cancer cell. Several chemotherapeutic drugs and traditional/herbal medicines reported for anticancer activities have been investigated for their selective delivery to cancer cells by active targeting nanoparticles. This systematic review summarizes reports on this application. Literature search was conducted through PubMed database search up to March 2017 using the terms nanoparticle, chemotherapy, traditional medicine, herbal medicine, natural medicine, natural compound, cancer treatment, and active targeting. Out of 695 published articles, 61 articles were included in the analysis based on the predefined inclusion and exclusion criteria. The targeting ligands included proteins/peptides, hyaluronic acid, folic acid, antibodies/antibody fragments, aptamer, and carbohydrates/polysaccharides. In vitro and in vivo studies suggest that active targeting nanoparticles increase selectivity in cellular uptake and/or cytotoxicity over the conventional chemotherapeutic drugs and non-targeted nanoparticle platform, particularly enhancement of drug efficacy and safety. However, clinical studies are required to confirm these findings.

Investigational agents to enhance the efficacy of chemotherapy or radiation in pancreatic cancer

Pancreatic cancer (PC) continues to be a fatal malignancy. With standard treatments having modest impact, alternative courses of actions are being investigated such as enhancing the efficacy of standard treatment through sensitization of PC cells to chemotherapy or radiation. This review emphasizes investigational agents that increase the responses to chemotherapy or radiation in PC models. Our group has extensively investigated on Curcumin (Cur), analogs (EF31, UBS109, and L49H37), nanoparticles and a small molecule Tolfenamic acid (TA) for enhancing therapeutic efficacy in both in vitro and in vivo assays. Cur has a low level of toxicity and promising anti-cancer activity, however, its clinical development has been limited by low bioavailability. Cur analogs and nanoparticles were synthesized to improve Cur's efficacy and bioavailability. These compounds were found to be effective in enhancing the therapeutic effects of chemotherapy in pre-clinical models. Small molecules such as NSAIDs have also been tested for the anti-cancer activity and induction of response of chemotherapy and radiation. Interest in TA, a NSAID, has recently increased due to promising preclinical data demonstrating its anti-cancer properties with minimum toxicity. TA also synergistically increased the response of XRT in PC cells and in an orthotropic mouse model. With strong preclinical evidence, research aimed at developing less toxic therapies for PC using Cur analogues or TA is ready for translation into clinical testing.

Combined use of adipose derived stem cells and TGF-β3 microspheres promotes articular cartilage regeneration in vivo

We investigated enhancement of articular cartilage regeneration using a combination of human adipose derived stem cells (hADSCs) and TGF-β3 microspheres (MS) in vivo. Poly-lactic-co-glycolic acid (PLGA)MS were prepared using a solid/oil/water emulsion solvent evaporation-extraction method. The morphology of the MS was evaluated by scanning electron microscopy (SEM). The release characteristic of the TGF-β3 MS was evaluated. A New Zealand rabbit model for experimental osteoarthritis (OA) was established using the anterior medial meniscus excision method. Thirty OA rabbits were divided randomly into three groups according to different treatments of the right knee joints on day 7 after surgery: hADSCs/MS group received injection of both hADSCs and TGF-β3 MS; hADSCs group was injected with hADSCs; control group was injected with normal saline. Gross observation, histological staining and RT-PCR for collagen II and aggrecan) were used to assess the severity of OA and for evaluating the effect of combined use of hADSCs and TGF-β3 MS on articular cartilage regeneration in vivo. The MS were spherical with a smooth surface and the average diameter was 28 ± 2.3 µm. The encapsulation efficiency test showed that 73.8 ± 2.9% of TGF-β3 were encapsulated in the MS. The release of TGF- β3 lasted for at least 30 days. At both 6 and 12 weeks after injection, three groups exhibited different degrees of OA. Histological analysis showed that the hADSCs/MS group exhibited less OA than the hADSCs group, and the control group exhibited the most severe OA. Real-time RT-PCR showed that the gene expression of both collagen II and aggrecan were significantly up-regulated in the hADSCs/MS group. At 12 weeks after injection, the hADSCs/MS group also exhibited less OA than the other two groups. Combined use of hADSCs and TGF-β3 MS promoted articular cartilage regeneration in rabbit OA models.

Design and immunological evaluation of anti-CD205-tailored PLGA-based nanoparticulate cancer vaccine

The aim of this research was to develop a targeted antigen–adjuvant assembled delivery system that will enable dendritic cells (DCs) to efficiently mature to recognize antigens released from tumor cells. It is important to target the DCs with greater efficiency to prime T cell immune responses. In brief, model antigen, ovalbumin (OV), and monophosphoryl lipid A adjuvant were encapsulated within the nanoparticle (NP) by double emulsification solvent evaporation method. Targeted NPs were obtained through ligand incorporation via physical adsorption or chemical conjugation process. Intracellular uptake of the NPs and the maturation of DCs were evaluated with flow cytometry. Remarkably, the developed delivery system had suitable physicochemical properties, such as particle size, surface charge, OV encapsulation efficiency, biphasic OV release pattern, and safety profile. The ligand modified formulations had higher targeting efficiency than the non-tailored NPs. This was also evident when the targeted formulations expressed comparatively higher fold increase in surface activation markers such as CD40, CD86, and major histocompatibility complex class II molecules. The maturation of DCs was further confirmed through secretion of extracellular cytokines compared to control cells in the DC microenvironment. Physicochemical characterization of NPs was performed based on the polymer end groups, their viscosities, and ligand-NP bonding type. In conclusion, the DC stimulatory response was integrated to develop a relationship between the NP structure and desired immune response. Therefore, the present study narrates a comparative evaluation of some selected parameters to choose a suitable formulation useful for in vivo cancer immunotherapy.

Targeted Therapeutic Nanoparticles: An Immense Promise to Fight against Cancer

In nanomedicine, targeted therapeutic nanoparticle (NP) is a virtual outcome of nanotechnology taking the advantage of cancer propagation pattern. Tying up all elements such as therapeutic or imaging agent, targeting ligand, and cross-linking agent with the NPs is the key concept to deliver the payload selectively where it intends to reach. The microenvironment of tumor tissues in lymphatic vessels can also help targeted NPs to achieve their anticipated accumulation depending on the formulation objectives. This review accumulates the application of poly(lactic-co-glycolic acid) (PLGA) and polyethylene glycol (PEG) based NP systems, with a specific perspective in cancer. Nowadays, PLGA, PEG, or their combinations are the mostly used polymers to serve the purpose of targeted therapeutic NPs. Their unique physicochemical properties along with their biological activities are also discussed. Depending on the biological effects from parameters associated with existing NPs, several advantages and limitations have been explored in teaming up all the essential facts to give birth to targeted therapeutic NPs. Therefore, the current article will provide a comprehensive review of various approaches to fabricate a targeted system to achieve appropriate physicochemical properties. Based on such findings, researchers can realize the benefits and challenges for the next generation of delivery systems.

Bone-targeted cabazitaxel nanoparticles for metastatic prostate cancer skeletal lesions and pain

Aim:

The aim of this study was to develop a novel cabazitaxel bone targeted nanoparticle (NP) system for improved drug delivery to the bone microenvironment.

Materials & methods:

Nanoparticles were developed using poly(D,L-lactic-co-glycolic acid) and cabazitaxel as the core with amino-bisphosphonate surface conjugation. Optimization of nanoparticle physiochemical properties, in vitro evaluation in prostate cancer cell lines and in vivo testing in an intraosseous model of metastatic prostate cancer was performed.

Results:

This bone targeted cabazitaxel nanocarrier system showed significant reduction in tumor burden, while at the same time maintaining bone structure integrity and reducing pain in the mouse tumor limb.

Conclusion:

This bone microenvironment targeted nanoparticle system and clinically relevant approach of evaluation represents a promising advancement for treating bone metastatic cancer.

Protein Nanocage Mediated Fibroblast-Activation Protein Targeted Photoimmunotherapy To Enhance Cytotoxic T Cell Infiltration and Tumor Control

Carcinoma-associated fibroblasts (CAFs) are found in many types of cancer and play an important role in tumor growth and metastasis. Fibroblast-activation protein (FAP), which is overexpressed on the surface of CAFs, has been proposed as a universal tumor targeting antigen. However, recent studies show that FAP is also expressed on multipotent bone marrow stem cells. A systematic anti-FAP therapy may lead to severe side effects and even death. Hence, there is an urgent need of a therapy that can selectively kill CAFs without causing systemic toxicity. Herein we report a nanoparticle-based photoimmunotherapy (nano-PIT) approach that addresses the need. Specifically, we exploit ferritin, a compact nanoparticle protein cage, as a photosensitizer carrier, and we conjugate to the surface of ferritin a FAP-specific single chain variable fragment (scFv). With photoirradiation, the enabled nano-PIT efficiently eliminates CAFs in tumors but causes little damage to healthy tissues due to the localized nature of the treatment. Interestingly, while not directly killing cancer cells, the nano-PIT caused efficient tumor suppression in tumor-bearing immunocompetent mice. Further investigations found that the nano-PIT led to suppressed C-X-C motif chemokine ligand 12 (CXCL12) secretion and extracellular matrix (ECM) deposition, both of which are regulated by CAFs in untreated tumors and mediate T cell exclusion that prevents physical contact between T cells and cancer cells. By selective killing of CAFs, the nano-PIT reversed the effect, leading to significantly enhanced T cell infiltration, followed by efficient tumor suppression. Our study suggests a new and safe CAF-targeted therapy and a novel strategy to modulate tumor microenvironment (TME) for enhanced immunity against cancer.

Rationalizing the use of functionalized poly-lactic-co-glycolic acid nanoparticles for dendritic cell-based targeted anticancer therapy

BACKGROUND

Delivery of PLGA (poly [D, L-lactide-co-glycolide])-based biodegradable nanoparticles (NPs) to antigen presenting cells, particularly dendritic cells, has potential for cancer immunotherapy.

MATERIALS & METHODS

Using a PLGA NP vaccine construct CpG-NP-Tag (CpG-ODN-coated tumor antigen [Tag] encapsulating NP) prepared using solvent evaporation technique we tested the efficacy of ex vivo and in vivo use of this construct as a feasible platform for immune-based therapy.

RESULTS

CpG-NP-Tag NPs were avidly endocytosed and localized in the endosomal compartment of bone marrow-derived dendritic cells. Bone marrow-derived dendritic cells exposed to CpG-NP-Tag NPs exhibited an increased maturation (higher CD80/86 expression) and activation status (enhanced IL-12 secretion levels). In vivo results demonstrated attenuation of tumor growth and angiogenesis as well as induction of potent cytotoxic T-lymphocyte responses.

CONCLUSION

Collectively, results validate dendritic cells stimulatory response to CpG-NP-Tag NPs (ex vivo) and CpG-NP-Tag NPs' tumor inhibitory potential (in vivo) for therapeutic applications, respectively.

Investigation and optimization of formulation parameters on preparation of targeted anti-CD205 tailored PLGA nanoparticles

The purpose of this study was to assess the effect of various formulation parameters on anti-CD205 antibody decorated poly(d, l-lactide co-glycolide) (PLGA) nanoparticles (NPs) in terms of their ability to target dendritic cells (DCs). In brief, emulsification solvent evaporation technique was adapted to design NP formulations using two different viscosity grades (low and high) of both ester and carboxylic acid terminated PLGA. Incorporation of ligand was achieved following physical adsorption or chemical conjugation processes. The physicochemical characterizations of formulations were executed to assess the effects of different solvents (chloroform and ethyl acetate), stabilizer percentage, polymer types, polymer viscosities, ligand-NP bonding types, cross-linkers, and cryoprotectants (sucrose and trehalose). Modification of any of these parameters shows significant improvement of physicochemical properties of NPs. Ethyl acetate was the solvent of choice for the formulations to ensure better emulsion formation. Infrared spectroscopy confirmed the presence of anti-CD205 antibody in the NP formulation. Finally, cytotoxicity assay confirmed the safety profile of the NPs for DCs. Thus, ligand modified structurally concealed PLGA NPs is a promising delivery tool for targeting DCs in vivo.

Therapeutic Applications of Curcumin Nanoformulations

Curcumin (diferuloylmethane) is a bioactive and major phenolic component of turmeric derived from the rhizomes of curcuma longa linn. For centuries, curcumin has exhibited excellent therapeutic benefits in various diseases. Owing to its anti-oxidant and anti-inflammatory properties, curcumin plays a significant beneficial and pleiotropic regulatory role in various pathological conditions including cancer, cardiovascular disease, Alzheimer's disease, inflammatory disorders, neurological disorders, and so on. Despite such phenomenal advances in medicinal applications, the clinical implication of native curcumin is hindered due to low solubility, physico-chemical instability, poor bioavailability, rapid metabolism, and poor pharmacokinetics. However, these issues can be overcome by utilizing an efficient delivery system. Active scientific research was initiated in 2005 to improve curcumin's pharmacokinetics, systemic bioavailability, and biological activity by encapsulating or by loading curcumin into nanoform(s) (nanoformulations). A significant number of nanoformulations exist that can be translated toward medicinal use upon successful completion of pre-clinical and human clinical trials. Considering this perspective, current review provides an overview of an efficient curcumin nanoformulation for a targeted therapeutic option for various human diseases. In this review article, we discuss the clinical evidence, current status, and future opportunities of curcumin nanoformulation(s) in the field of medicine. In addition, this review presents a concise summary of the actions required to develop curcumin nanoformulations as pharmaceutical or nutraceutical candidates.

Enhancement of anti-tumor effect of particulate vaccine delivery system by 'bacteriomimetic' CpG functionalization of poly-lactic-co-glycolic acid nanoparticles

AIM

Low immunogenicity remains a major obstacle in realizing the full potential of cancer vaccines. In this study, we evaluated CpG-coated tumor antigen (Tag)-encapsulating 'bacteriomimetic' nanoparticles (CpG-nanoparticle [NP]-Tag NPs) as an approach to enhance anti-tumor immunity.

MATERIALS & METHODS

CpG-NP-Tag NPs were synthesized, characterized for their physicochemical properties and tested in vivo.

RESULTS

We found CpG predosing followed by intraperitoneal (IP) immunization with CpG-NP-Tag NPs significantly attenuated tumor growth in female BALB/c mice compared with respective controls. Histopathological and Immunofluorescence data revealed CpG-NP-Tag tumors had lower proliferation, higher apoptotic activity, greater CD4(+) and CD8(+) T cell infiltration as well as higher IFN-γ levels as compared with control groups.

CONCLUSION

Our findings suggest CpG-NP-Tag NPs can enhance anti-tumor effect of nanoparticulate tumor vaccination system.

The biocompatibility of calcium phosphate cements containing alendronate-loaded PLGA microparticles in vitro

The composite of poly-lactic-co-glycolic acid (PLGA) and calcium phosphate cements (CPC) are currently widely used in bone tissue engineering. However, the properties and biocompatibility of the alendronate-loaded PLGA/CPC (APC) porous scaffolds have not been characterized. APC scaffolds were prepared by a solid/oil/water emulsion solvent evaporation method. The morphology, porosity, and mechanical strength of the scaffolds were characterized. Bone marrow mesenchymal stem cells (BMSCs) from rabbit were cultured, expanded and seeded on the scaffolds, and the cell morphology, adhesion, proliferation, cell cycle and osteogenic differentiation of BMSCs were determined. The results showed that the APC scaffolds had a porosity of 67.43 ± 4.2% and pore size of 213 ± 95 µm. The compressive strength for APC was 5.79 ± 1.21 MPa, which was close to human cancellous bone. The scanning electron microscopy, cell counting kit-8 assay, flow cytometry and ALP activity revealed that the APC scaffolds had osteogenic potential on the BMSCs in vitro and exhibited excellent biocompatibility with engineered bone tissue. APC scaffolds exhibited excellent biocompatibility and osteogenesis potential and can potentially be used for bone tissue engineering.

A nanotherapy strategy significantly enhances anticryptosporidial activity of an inhibitor of bifunctional thymidylate synthase-dihydrofolate reductase from Cryptosporidium

Cryptosporidiosis, a gastrointestinal disease caused by protozoans of the genus Cryptosporidium, is a common cause of diarrheal diseases and often fatal in immunocompromised individuals. Bifunctional thymidylate synthase-dihydrofolate reductase (TS-DHFR) from Cryptosporidium hominis (C. hominis) has been a molecular target for inhibitor design. C. hominis TS-DHFR inhibitors with nM potency at a biochemical level have been developed however drug delivery to achieve comparable antiparasitic activity in Cryptosporidium infected cell culture has been a major hurdle for designing effective therapies. Previous mechanistic and structural studies have identified compound 906 as a nM C. hominis TS-DHFR inhibitor in vitro, having μM antiparasitic activity in cell culture. In this work, proof of concept studies are presented using a nanotherapy approach to improve drug delivery and the antiparasitic activity of 906 in cell culture. We utilized PLGA nanoparticles that were loaded with 906 (NP-906) and conjugated with antibodies to the Cryptosporidium specific protein, CP2, on the nanoparticle surface in order to specifically target the parasite. Our results indicate that CP2 labeled NP-906 (CP2-NP-906) reduces the level of parasites by 200-fold in cell culture, while NP-906 resulted in 4.4-fold decrease. Moreover, the anticryptosporidial potency of 906 improved 15 to 78-fold confirming the utility of the antibody conjugated nanoparticles as an effective drug delivery strategy.

Co-association of methotrexate and SPIONs into anti-CD64 antibody-conjugated PLGA nanoparticles for theranostic application

Background

Rheumatoid arthritis (RA) is an autoimmune disease with severe consequences for the quality of life of sufferers. Regrettably, the inflammatory process involved remains unclear, and finding successful therapies as well as new means for its early diagnosis have proved to be daunting tasks. As macrophages are strongly associated with RA inflammation, effective diagnosis and therapy may encompass the ability to target these cells. In this work, a new approach for targeted therapy and imaging of RA was developed based on the use of multifunctional polymeric nanoparticles.

Methods

Poly(lactic-co-glycolic acid) nanoparticles were prepared using a single emulsion-evaporation method and comprisaed the co-association of superparamagnetic iron oxide nanoparticles (SPIONs) and methotrexate. The nanoparticles were further functionalized with an antibody against the macrophage-specific receptor, CD64, which is overexpressed at sites of RA. The devised nanoparticles were characterized for mean particle size, polydispersity index, zeta potential, and morphology, as well as the association of SPIONs, methotrexate, and the anti-CD64 antibody. Lastly, the cytotoxicity of the developed nanoparticles was assessed in RAW 264.7 cells using standard MTT and LDH assays.

Results

The nanoparticles had a mean diameter in the range of 130–200 nm and zeta potential values ranging from −32 mV to −16 mV. Association with either methotrexate or SPIONs did not significantly affect the properties of the nanoparticles. Conjugation with the anti-CD64 antibody, in turn, caused a slight increase in size and surface charge. Transmission electron microscopy confirmed the association of SPIONs within the poly(lactic-co-glycolic acid) matrix. Both anti-CD64 and methotrexate association were confirmed by Fourier transform infrared spectroscopy, and quantified yielding values as high as 36% and 79%, respectively. In vitro toxicity studies confirmed the methotrexate-loaded nanosystem to be more effective than the free drug.

Conclusion

Multifunctional anti-CD64-conjugated poly(lactic-co-glycolic acid) nanoparticles for the combined delivery of methotrexate and SPIONs were successfully prepared and characterized. This nanosystem has the potential to provide a new theranostic approach for the management of RA.

Curcumin nanomedicine: a road to cancer therapeutics

Cancer is the second leading cause of death in the United States. Conventional therapies cause widespread systemic toxicity and lead to serious side effects which prohibit their long term use. Additionally, in many circumstances tumor resistance and recurrence is commonly observed. Therefore, there is an urgent need to identify suitable anticancer therapies that are highly precise with minimal side effects. Curcumin is a natural polyphenol molecule derived from the Curcuma longa plant which exhibits anticancer, chemopreventive, chemo- and radio-sensitization properties. Curcumin's widespread availability, safety, low cost and multiple cancer fighting functions justify its development as a drug for cancer treatment. However, various basic and clinical studies elucidate curcumin's limited efficacy due to its low solubility, high rate of metabolism, poor bioavailability and pharmacokinetics. A growing list of nanomedicine(s) using first line therapeutic drugs have been approved or are under consideration by the Food and Drug Administration (FDA) to improve human health. These nanotechnology strategies may help to overcome challenges and ease the translation of curcumin from bench to clinical application. Prominent research is reviewed which shows that advanced drug delivery of curcumin (curcumin nanoformulations or curcumin nanomedicine) is able to leverage therapeutic benefits by improving bioavailability and pharmacokinetics which in turn improves binding, internalization and targeting of tumor(s). Outcomes using these novel drug delivery systems have been discussed in detail. This review also describes the tumor-specific drug delivery system(s) that can be highly effective in destroying tumors. Such new approaches are expected to lead to clinical trials and to improve cancer therapeutics.

AS1411 aptamer tagged PLGA-lecithin-PEG nanoparticles for tumor cell targeting and drug delivery

Liposomes and polymers are widely used drug carriers for controlled release since they offer many advantages like increased treatment effectiveness, reduced toxicity and are of biodegradable nature. In this work, anticancer drug-loaded PLGA-lecithin-PEG nanoparticles (NPs) were synthesized and were functionalized with AS1411 anti-nucleolin aptamers for site-specific targeting against tumor cells which over expresses nucleolin receptors. The particles were characterized by transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). The drug-loading efficiency, encapsulation efficiency and in vitro drug release studies were conducted using UV spectroscopy. Cytotoxicity studies were carried out in two different cancer cell lines, MCF-7 and GI-1 cells and two different normal cells, L929 cells and HMEC cells. Confocal microscopy and flowcytometry confirmed the cellular uptake of particles and targeted drug delivery. The morphology analysis of the NPs proved that the particles were smooth and spherical in shape with a size ranging from 60 to 110 nm. Drug-loading studies indicated that under the same drug loading, the aptamer-targeted NPs show enhanced cancer killing effect compared to the corresponding non-targeted NPs. In addition, the PLGA-lecithin-PEG NPs exhibited high encapsulation efficiency and superior sustained drug release than the drug loaded in plain PLGA NPs. The results confirmed that AS1411 aptamer-PLGA-lecithin-PEG NPs are potential carrier candidates for differential targeted drug delivery.

Is dialysis a reliable method for studying drug release from nanoparticulate systems?-A case study

The kinetics of in vitro drug release from nanoparticulate systems is extensive, though uncritically, being studied by dialysis. Evaluating the actual relevance of dialysis data to drug release was the purpose of this study. Diclofenac- or ofloxacin-loaded chitosan nanoparticles crosslinked with tripolyphosphate were prepared and characterized. With each drug, dynamic dialysis was applied to nanoparticle dispersion, solution containing dissolved chitosan·HCl, and solution of plain drug. Drug kinetics in receiving phase (KRP), nanoparticle matrix (KNM) and nanoparticle dispersion medium (KDM) were determined. Release of each drug from nanoparticles was also assessed by ultracentrifugation. Although KRP data may be interpreted in terms of sustained release from nanoparticles, KNM and KDM data show that, with both drugs, the process was in fact controlled by permeation across dialysis membrane. Analysis of KRP data reveals a reversible interaction of diclofenac with dispersed nanoparticle surface, similar to the interaction of this drug with dissolved chitosan·HCl. No such interactions are noticed with ofloxacin. The results from the ultracentrifugation method agree with the above interpretation of dialysis data. This case study shows that dialysis data from a nanoparticle dispersion is not necessarily descriptive of sustained-release from nanoparticles, hence, if interpreted uncritically, it may be misleading.

Preparation and in vitro evaluation of a folate-linked liposomal curcumin formulation

Curcumin (CUR), a plant-derived compound, exhibits versatile antitumor effects. However, its poor hydrophilic property limits its application. To circumvent these drawbacks, we encapsulated CUR in liposomes modified with folic acid for better solubility and enhanced tumor targeting. This novel formulation was prepared by a film-dispersion method and characterized by size, zeta potential, drug-loading efficiency, and physical-condition stability. In vitro, cellular uptake efficiency, cytotoxicity, and apoptosis analysis by flow cytometry were performed to evaluate tumor targeting and killing ability. Results showed that the folate-receptor (FR)-targeted liposomal CUR (F-CUR-L) performed with improved solubility, sufficient stability, and enhanced antitumor activity. Mean diameter, zeta potential, and drug-loading efficiency were 182 nm, -26 mV, and 68%, respectively, and this formulation exhibited stability in storage at 4 °C for 1 month. In vitro, FR-positive cells endocytosed more F-CUR-L than nontargeted liposomal CUR (CUR-L); thus, the former induced more cellular proliferation inhibition and higher apoptosis than the latter, and the enhanced targeting could be hindered by 1 mM of free folic acid. Further, KB cells were more sensitive to F-CUR-L, compared to Hela cells. Finally, the two kinds of tumor cells treated with F-CUR-L also showed dose- and time-dependent apoptosis.

Aptamer-labeled PLGA nanoparticles for targeting cancer cells

Cancer is one of the leading causes of death in most parts of the world and is a very serious cause of concern particularly in developing countries. In this work, we prepared and evaluated the aptamer-labeled paclitaxel-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (Apt-PTX-PLGA NPs) which can ameliorate drug bioavailability and enable accurate drug targeting to cancer cells with controlled drug release for cancer therapy. Paclitaxel-loaded PLGA nanoparticles (PTX-PLGA NPs) were formulated by a single-emulsion/solvent evaporation method and were further surface-functionalized with a chemical cross-linker bis(sulfosuccinimidyl) suberate (BS3) to enable binding of aptamer on to the surface of the nanoparticles. The prepared nanoparticles were characterized by atomic force microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. Cytotoxicity studies were carried out using normal human mammary epithelial cells (HMEC cells) and human glial cancer cells (GI-1 cells) by methylthiazolyldiphenyl-tetrazolium bromide assay and Alamar blue assay, which confirmed that PTX-PLGA NPs with aptamer conjugation (Apt-PTX-PLGA NPs) were comparatively non-toxic to HMEC cells while toxic to GI-1 cancer cells. Cellular uptake of PTX-PLGA NPs with and without aptamer conjugation was studied using GI-1 cells and monitored by confocal microscopy and phase contrast microscopy. Our studies demonstrated significant internalization and retention of nanoparticles inside the cells, inducing apoptosis. The preferential accumulation of PTX-PLGA NPs within the cancer cells were also confirmed by flow cytometry-based uptake studies. The results indicated that Apt-PTX-PLGA NPs could be a promising targeted therapeutic delivery vehicle for cancer treatment.

Curcumin nanoformulations: a future nanomedicine for cancer

Curcumin, a natural diphenolic compound derived from turmeric Curcuma longa, has proven to be a modulator of intracellular signaling pathways that control cancer cell growth, inflammation, invasion and apoptosis, revealing its anticancer potential. In this review, we focus on the design and development of nanoparticles, self-assemblies, nanogels, liposomes and complex fabrication for sustained and efficient curcumin delivery. We also discuss the anticancer applications and clinical benefits of nanocurcumin formulations. Only a few novel multifunctional and composite nanosystem strategies offer simultaneous therapy as well as imaging characteristics. We also summarize the challenges to developing curcumin delivery platforms and up-to-date solutions for improving curcumin bioavailability and anticancer potential for therapy.

A sustained release formulation of chitosan modified PLCL:poloxamer blend nanoparticles loaded with optical agent for animal imaging

The objective of this study was to develop optical imaging agent loaded biodegradable nanoparticles with indocynanine green (ICG) using chitosan modified poly(L-lactide-co-epsilon-caprolactone) (PLCL):poloxamer (Pluronic F68) blended polymer. Nanoparticles were formulated with an emulsification solvent diffusion technique using PLCL and poloxamer as blend-polymers. Polyvinyl alcohol (PVA) and chitosan were used as stabilizers. The particle size, shape and zeta potential of the formulated nanoparticles and the release kinetics of ICG from these nanoparticles were determined. Further, biodistribution of these nanoparticles was studied in mice at various time points until 24 h following intravenous administration, using a non-invasive imaging system. The average particle size of the nanoparticles was found to be 146 ± 3.7 to 260 ± 4.5 nm. The zeta potential progressively increased from - 41.6 to + 25.3 mV with increasing amounts of chitosan. Particle size and shape of the nanoparticles were studied using transmission electron microscopy (TEM) which revealed the particles to be smooth and spherical in shape. These nanoparticles were efficiently delivered to the cytoplasm of the cells, as observed in prostate and breast cancer cells using confocal laser scanning microscopy. In vitro release studies indicated sustained release of ICG from the nanoparticles over a period of seven days. Nanoparticle distribution results in mice showing improved uptake and accumulation with chitosan modified nanoparticles in various organs and slower clearance at different time points over a 24 h period as compared to unmodified nanoparticles. The successful formulation of such cationically modified nanoparticles for encapsulating optical agents may lead to a potential deep tissue imaging technique for tumor detection, diagnosis and therapy.