Folate-modified Nanoparticles Research Articles

GSH-responsive and folate receptor-targeted pyridine bisfolate-encapsulated chitosan nanoparticles for enhanced intracellular drug delivery in MCF−7 cells

Folic acid receptor-targeted drug delivery system is a promising candidate for tumor-targeted delivery because its elevated expression specifically on tumor cells enables the selective delivery of cytotoxic cargo to cancerous tissue, thereby minimizing toxic side effects and increasing the therapeutic index. Pyridine bisfolate-chitosan (PyBFA@CS NPs) and folate-chitosan nanocomposite (FA@CS NPs) were synthesized with suitable particle size (256.0 ± 15.0 and 161.0 ± 5.0 nm), high stability (ζ = −27.0 ± 0.1 and −30.0 ± 0.2 mV), respectively, and satisfactory biocompatibility to target cells expressing folate receptors and try to answer the question: Is the metal center always important for activity? Since almost all pharmaceuticals work by binding to specific proteins or DNA, the in vitro binding of human serum albumin (HSA) to PyBFA@CS NPs and FA@CS NPs has been investigated and compared with PyBFA. Strong affinity to HSA is shown by quenching and binding constants in the range of 105 and 104 M−1, respectively with PyBFA@CS NPs showing the strongest. The compounds-HSA kinetic stability, affinity, and association constants were investigated using a stopped-flow method. The findings showed that all formulations bind by a static quenching mechanism that consists of two reversible steps: rapid second-order binding and a more slowly first-order isomerization reaction. The overall coordination affinity of HSA to PyBFA@CS NPs (6.6 × 106 M−1), PyBFA (4.4 × 106 M−1), and FA@CS NPs (1.3 × 106 M−1) was measured and The relative reactivity is roughly (PyBFA@CS NPs)/(PyBFA)/(FA@CS NPs) = 5/3/1. Additionally, in vitro cytotoxicity revealed that, consistent with the binding constants and coordination affinity, active-targeting formulations greatly inhibited FR-positive MCF-7 cells in compared to FRs-negative A549 cells in the following trend: PyBFA@CS NPs > PyBFA > FA@CS NPs. Furthermore, in vitro drug release of PyBFA@CS NPs was found to be stable in PBS at pH 7.4, however, the in pH 5.4 and in pH 5.4 containing 10 mM glutathione (GSH) (mimicking the tumor microenvironment) reached 43 % and 73 %, respectively indicating that the PyBFA@CS NPs system is sensitive to GSH. Folate-modified nanoparticles, PyBFA@CS NPs, are a promising therapeutic for MCF-7 therapy because they not only showed a greater affinity for HSA, but also showed higher cleavage efficiency toward the minor groove of pBR322 DNA via the hydrolytic way, as well as effective antibacterial activity that avoids the usage of extra antibiotics.‬‬‬‬‬‬‬‬‬‬‬‬ ‬‬‬‬‬‬‬‬‬‬‬‬‬‬

Folate-Modified Curcumin-Loaded Nanoparticles for Overcoming Delivery Challenges in Cancer Treatment: A Narrative Review.

Curcumin, as an anti-tumor agent, is not widely used in cancer treatment due to the lack of effective levels of its metabolites in cancerous tissue. Addressing the barriers to the carrier and delivery of drugs to the specific sites of therapeutic action while reducing side effects is a priority. Folate receptor expression is high in malignant and low in normal cells. Folate as a targeted ligand could selectively target cancer cells. Thus, this narrative review aimed to provide an overview of the studies that have investigated the different types of folate-modified curcumin as a carrier and deliverer and their structural properties that enhance therapeutic drug efficacy. A literature search was performed using PubMed, Scopus, Web of Science, and Google Scholar databases. Thirty-eight preclinical studies addressing this topic were identified. The findings of the current review have shown that folate-modified nanoparticles containing curcumin as a promising therapeutic approach can be effective in improving different types of cancers. In vitro studies have shown a higher cellular uptake and cytotoxicity effect, higher cell inhibition, and anti-proliferation with a lower dosage of curcumin. In vivo studies have shown more tumor suppression and smaller tumor volume without toxicity after the administration of folate-modified nanoparticles containing curcumin. Future clinical trials are needed to confirm the beneficial effect of folate-modified curcumin as a new drug delivery platform for cancer treatment.

Design of functionalized magnetic silica multi-core composite nanoparticles for synergistic magnetic hyperthermia/radiotherapy in cancer cells

Nanomaterials in particular the magnetic nanoparticles (MNPs) offer tremendous potential for cancer treatment due to their unique intrinsic properties. Combining materials with a variety of functional groups, and forming a multifunctional nanosystem to overcome the limitations of monotherapy for cancer treatment has always been a research focus with notable difficulties. Considering the many challenges faced by radiotherapy and hyperthermia, in this study, we designed a rational strategy for magnetic hyperthermia using Fe3O4@SiO2@Sec2@FA nanoparticles as a novel nano-radiosensitizer to simultaneously enhance the therapeutic effects of radiotherapy in the future. Fe3O4@SiO2 core–shell structured nanoparticles were synthesized with an appropriate silica layer thickness to maintain good saturation magnetization. The as-prepared Fe3O4@SiO2@Sec2@FA nanoparticles had the specific absorption rate (SAR)value of 57 W/g, which was below the clinically acceptable alternating magnetic field value of 4.9 × 109 Am−1s−1, indicating good heat generation efficiency (the temperature level ΔT=6–10 °C). Moreover, Folate-modified nanoparticles exhibited approximately 6-fold higher cellular internalization of Hela cells with no obvious cytotoxicity for the Hela and MDA-MB-231 cells, and lower cytotoxicity for the HUVECs in a concentration range of 0–150 µg/mL. In addition, these nanoparticles were modified on the silica surface by L-selenocystine, which could enhance the elimination of tumor cells by producing reactive oxygen species under X-rays, resulting in a novel radiosensitization effect. Therefore, the as-prepared Fe3O4@SiO2@Sec2@FA nanoparticles with good biocompatibility and active targeting would possess synergistic magnetic hyperthermia/radiotherapy effect.

5-Fluorouracil-Loaded Folic-Acid-Fabricated Chitosan Nanoparticles for Site-Targeted Drug Delivery Cargo.

Nanoparticles play a vital role in cancer treatment to deliver or direct the drug to the malignant cell, avoiding the attacking of normal cells. The aim of the study is to formulate folic-acid-modified chitosan nanoparticles for colon cancer. Chitosan was successfully conjugated with folic acid to produce a folic acid–chitosan conjugate. The folate-modified chitosan was loaded with 5-FU using the ionic gelation method. The prepared nanoparticles were characterized for size, zeta potential, surface morphology, drug contents, entrapment efficiency, loading efficiency, and in vitro release study. The cytotoxicity study of the formulated nanoparticles was also investigated. The conjugation of folic acid with chitosan was confirmed by FTIR and NMR spectroscopy. The obtained nanoparticles were monodispersed nanoparticles with a suitable average size and a positive surface charge. The size and zeta potential and PDI of the CS-5FU-NPs were 208 ± 15, 26 ± 2, and +20 ± 2, respectively, and those of the FA-CS-5FU-NPs were 235 ± 12 and +20 ± 2, respectively, which are in the acceptable ranges. The drug contents’ % yield and the %EE of folate-decorated NPs were 53 ± 1.8% and 59 ± 2%, respectively. The in vitro release of the FA-CS-5FU-NPs and CS-5FU-NPs was in the range of 10.08 ± 0.45 to 96.57 ± 0.09% and 6 ± 0.31 to 91.44 ± 0.21, respectively. The cytotoxicity of the nanoparticles was enhanced in the presence of folic acid. The presence of folic acid in nanoparticles shows much higher cytotoxicity as compared to simple chitosan nanoparticles. The folate-modified nanoparticles provide a potential way to enhance the targeting of tumor cells.

In vitro evaluation of folate-modified PLGA nanoparticles containing paclitaxel for ovarian cancer therapy.

Ovarian cancer is the most lethal gynecological cancer of female reproductive system. In order to improve the survival rate, some modifications on nanoparticles surfaces have been investigated to promote active targeting of drugs into tumor microenvironment. The aim of this study was the development and characterization of folate-modified (PN-PCX-FA) and unmodified PLGA nanoparticles (PN-PCX) containing paclitaxel for ovarian cancer treatment. Nanocarriers were produced using nanoprecipitation technique and characterized by mean particle diameter (MPD), polydispersity index (PDI), zeta potential (ZP), encapsulation efficiency (EE), DSC, FTIR, in vitro cytotoxicity and cellular uptake. PN-PCX and PN-PCX-FA showed MPD < 150 nm and PDI < 0.2 with high EE (about 90%). Cytotoxicity assays in SKOV-3 cells demonstrated the ability of both formulations to cause cellular damage. PCX encapsulated in PN-PCX-FA at 1 nM showed higher cytotoxicity than PN-PCX. Folate-modified nanoparticles showed a 3.6-fold higher cellular uptake than unmodified nanoparticles. PN-PCX-FA is a promising system to improve safety and efficacy of ovarian cancer treatment. Further in vivo studies are necessary to prove PN-PCX-FA potential.

Folate Receptor-Targeted and GSH-Responsive Carboxymethyl Chitosan Nanoparticles Containing Covalently Entrapped 6-Mercaptopurine for Enhanced Intracellular Drug Delivery in Leukemia.

For enhanced intracellular accumulation of 6-mercaptopurine (6-MP) in leukemia, a folate receptor-targeted and glutathione (GSH)-responsive polymeric prodrug nanoparticle was made. The nanoparticles were prepared by conjugating 6-MP to carboxymethyl chitosan via a GSH-sensitive carbonyl vinyl sulfide linkage, ultrasonic self-assembly and surface decoration with folate. The TEM graphs shows that the as-synthesized nanoparticles are spherical with a particle size of 170~220 nm. In vitro drug release of nanoparticles demonstrated acceptable stability in PBS containing 20 μM GSH at pH 7.4. However, the cumulative drug release rate of the samples containing 20 mM and 10 mM GSH medium reached 78.9% and 64.8%, respectively, in pH 5.0 at 20 h. This indicated that this nano-sized system is highly sensitive to GSH. The inhibition ratio of folate-modified nanoparticles compared to unmodified nanoparticles was higher in cancer cells (human promyelocytic leukemia cells, HL-60) while their cytotoxicity was lower in normal cells (mouse fibroblast cell lines, L929). Furthermore, in vitro cancer cell incubation studies confirmed that folate-modified nanoparticles therapeutics were significantly more effective than unmodified nanoparticles therapeutics. Our results suggest that folate receptor-targeting and GSH-stimulation can significantly elevate tumour intracellular drug release. Therefore, folate-modified nanoparticles containing chemoradiotherapy is a potential treatment for leukemia therapy.

Folate-modified PLGA nanoparticles for tumor-targeted delivery of pheophorbide a in vivo

Targeted drug delivery has been an important issue for tumor therapy including photodynamic therapy (PDT). The purpose of our study is to increase the targeting efficiency of photosensitizer (PS) using folate-modified nanoparticles (NPs) to tumor site in vivo. Folate receptor is over-expressed on the surface of many human cancer cells. We prepared poly (lactic-co-glycolic acid) (PLGA) NPs containing pheophorbide a (Pba), a PS that is used in PDT and generates free radical for killing cancer cells. The surface of NPs was composed of phospholipids modified with polyethylene glycol (PEG) and folate (FA). The size of the resulting FA-PLGA-Pba NPs was about 200 nm in PBS at pH 7.4 and they were stable for long time. They showed faster cellular uptake to MKN28 human gastric cancer cell line than control PLGA-Pba NPs by high-affinity binding with folate receptors on cell surface. In MTT assay, FA-PLGA-Pba NPs also showed enhanced tumor cell killing compared to control PLGA-Pba NPs. In vivo and ex vivo imaging showed high accumulation of FA-PLGA-Pba NPs in tumor site during 24 h after intravenous injection to MKN28 tumor-bearing mice model. These results demonstrate that our FA-PLGA-Pba NPs are useful for tumor-targeted delivery of PS for cancer treatment by PDT.

Folate modified nanoparticles for targeted co-delivery chemotherapeutic drugs and imaging probes for ovarian cancer

Ovarian cancer has been the leading cause of death worldwide in gynecologic malignancy mainly due to the lack of ultrasensitive diagnosis approaches at its early stage and high cytotoxicity of anticancer drugs to normal cells. In an attempt to overcome the problems, a co-delivery system of folic acid (FA) modified nanoparticles were developed for early diagnosis and to maximize the therapeutic outcome. In the present study, we formulated a diblock copolymer of methoxy poly (ethylene glycol)-b-poly (ϵ-caprolactone)(mPEG-b-PCL) polymer micelles, and FA was further conjugated to endow micelles with active targeted capacity. Then paclitaxel (PTX) and superparamagnetic iron oxide (SPIO) were encapsulated in the core of micelles. The in vitro tumor cell targeting capability of FA-NP/SPIO/PTX and NP/ SPIO/PTX nanoparticles was assessed by confocal laser scanning microscopy (CLSM) with human ovarian cancer (SKOV3 cells) which overexpresses FA receptor. Quantitative analysis showed the amount of intracellular Fe in cells incubated with FA-NP/SPIO/PTX nanoparticles was about 13-fold higher than with NP/SPIO/PTX nanoparticles. The imaging contrast capability of FA-NP/SPIO/PTX nanoparticles as a sensitive MRI probe was evaluated by a 3 T clinical MR imaging scanner. The T2 -weighted imaging of cells incubated with targeting nanoparticles was found to have more sensitive imaging enhancement effect on the SKOV3 cells than non-targeting nanoparticles. Furthermore, the antitumor efficiency of targeting nanoparticles was approximately 5-fold higher than that of their counterparts, which further affirmed the feasibility of attaining the higher therapeutic efficacy of antitumor drugs while minimizing damage to healthy cells. The targeting nanoparticles exhibited the biphasic release characteristic in vitro. The results indicated that folate-modified nanoparticles could achieve high targeting specificity, high efficiency of delivery drug and excellent imaging enhancement. Therefore, the targeting nanoplatform has good prospects in non-invasively detecting early ovarian tumors, maximizing the therapeutic efficiency and real-time monitoring of therapeutic response, which can make it possible to lengthen patients’ survival and ultimately achieve the goal of individualized medicine for ovarian cancer in the near future.

Folate-modified bexarotene-loaded bovine serum albumin nanoparticles as a promising tumor-targeting delivery system.

Bexarotene (BEX), a high-affinity agonist for retinoid X receptors (RXRs), shows apparent biological activities and distinct inhibitive efficacy in both cancer therapy and prevention. This study exploited a folate-decorated delivery of bexarotene-loaded bovine serum albumin nanoparticles, which could solubilize the poorly water-soluble drug and overcome the nonspecific targeting disadvantage. Bexarotene-loaded bovine serum albumin nanoparticles (BEX-BSANPs) were optimized by a desolvation technique, subsequently conjugated with folate by carbodiimide reaction. The resultant folate-modified bexarotene-loaded bovine serum albumin nanoparticles (FA-BEX-BSANPs) showed a spherical shape, with a diameter of 195.3 ± 5.6 nm, a zeta potential of -33.64 ± 1.97 mV, and 71.28 ± 1.93 μg folate was coupled per mg BSA. Differential scanning calorimetry and X-ray diffraction analysis confirmed the amorphous state of bexarotene in the folate-conjugates. The in vitro drug release of bexarotene presented a controlled and sustained release pattern. The in vitro cytotoxicity, cell apoptosis and cellular uptake experiments of the nanoparticles were performed by MTT assay, propidium iodide staining, fluorescence microscopy and flow cytometric analysis on A549 and MCF-7 cancer cells. Both the BEX-BSANPs and FA-BEX-BSANPs induced an enhanced cancer cell apoptotic effect in contrast to BEX solution. The cells showed an excellent binding for folate-modified nanoparticles. Especially, the interference effect on the cellular internalization process by an excess folic acid was relatively dramatic for the FR-positive MCF-7 cells in comparison to the modest change seen in the FR-negative A549 cell lines, indicating that the uptake was mediated by the folate receptors. Together these data suggested that the folate-modified bexarotene-loaded delivery system, which demonstrated better biocompatibility and potential superiority, could be an appropriate cancer therapy in targeting tumors in the future.

Folate-Targeted Gadolinium-Lipid-Based Nanoparticles as a Bimodal Contrast Agent for Tumor Fluorescent and Magnetic Resonance Imaging

To enhance tumor magnetic resonance imaging (MRI) signals via the selective accumulation of contrast agents, we prepared folate-modified gadolinium-lipid-based nanoparticles as MRI contrast agents. Folate-modified nanoparticles were comprised of polyethylene glycol (PEG)-lipid, gadolinium diethylenetriamine pentaacetic acid lipid, cationic cholesterol derivatives, folate-conjugated PEG-lipid, and Cy7-PEG-lipid. Folate receptor-mediated cellular nanoparticle association was examined in KB cells, which overexpress the folate receptor. The biodistribution of nanoparticles after their intravenous injection into KB tumor-bearing mice was measured. Mice were imaged through in vivo fluorescence imaging and MRI 24 h after nanoparticle injection, and the intensity enhancement of the tumor MRI signal was evaluated. Increased cellular association of folate-modified nanoparticles was inhibited by excess free folic acid, indicating that nanoparticle association was folate receptor-mediated. Irrespective of folate modification, the amount of nanoparticles in blood 24 h after injection was ca. 10% of the injected dose. Compared with non-modified nanoparticles, folate-modified nanoparticles exhibited significant accumulation in tumor tissues without altering other biodistribution, as well as enhanced tumor fluorescence and MRI signal intensity. The results support the feasibility of MRI- and in vivo fluorescence imaging-based tumor visualization using folate-modified nanoparticles and provide opportunities to develop folate targeting-based imaging applications.

Specific uptake of folate-decorated triamcinolone-encapsulating nanoparticles by retinal pigment epithelium cells enhances and prolongs antiangiogenic activity

We are proposing folate-decorated polymeric nanoparticles as carriers of poorly soluble drug molecules for intracellular and prolonged delivery to retinal pigment epithelium (RPE) cells. RPE is a monolayer of epithelial cells that forms the outer blood-retinal barrier in the posterior segment of the eye, and is also implicated in the pathology of, such as neovascularization in age-related macular degeneration (AMD). In this study, folate-functionalized poly(ethylene glycol)-b-polycaprolactone (folate-PEG-b-PCL) were synthesized for assembling into nanoparticles of ~130nm. These nanoparticles were internalized into ARPE-19 (human RPE cell line) via receptor-mediated endocytosis, and the cellular uptake was significantly higher than particles without folate modification. Triamcinolone acetonide (TA) was efficiently encapsulated (>97%) into the folate-decorated nanoparticles and was slowly released over a period of 4weeks at pH 5.5 and 8weeks at pH 7.4. The enhanced uptake and controlled release resulted in prolonged anti-angiogenic gene expression of RPE cells. In cell culture, the down-regulation of vascular endothelial growth factor (VEGF) and up-regulation of pigment epithelium derived factor (PEDF) lasted for at least 3weeks. Unlike benzyl alcohol, the surfactant found in commercial formulation, folate-modified nanoparticles were non-toxic. Furthermore, TA became less cytotoxic by being encapsulated in the nanoparticles. Our findings suggest that folate-PEG–PCL nanoparticles are promising drug carriers for RPE targeting.