Polymeric micelles loaded with platinum anticancer drugs target preangiogenic micrometastatic niches associated with inflammation

Polymeric Nanosystems: A Breakthrough Approach to Treating Inflammation and Inflammation Related Diseases

Inflammation processes can cause mild to severe damage in the human body and can lead to a large number of inflammation-related diseases (IRD) such as cancer, neural, vascular, and pulmonary diseases. Limitations of anti-inflammatory drugs (AID) application are reflected in high therapeutic doses, toxicity, low bioavailability and solubility, side effects, etc. Polymeric nanosystems (PS) have been recognized as a safe and effective technology that is able to overcome these limitations by AID encapsulation and is able to answer to the specific demands of the IRD treatment. PS are attracting great attention due to their versatility, biocompatibility, low toxicity, fine-tuned properties, functionality, and ability for precise delivery of anti-inflammatory drugs to the targeted sites in the human body. This article offers an overview of three classes of polymeric nanosystems: a) dendrimers, b) polymeric micelles and polymeric nanoparticles, and c) polymeric filomicelles, as well as their properties, preparation, and application in IRD treatment. In the future, the number of PS formulations in clinical practice will certainly increase.

Platinum-Based Nanoformulations for Glioblastoma Treatment: The Resurgence of Platinum Drugs?

Current therapies for treating Glioblastoma (GB), and brain tumours in general, are inefficient and represent numerous challenges. In addition to surgical resection, chemotherapy and radiotherapy are presently used as standards of care. However, treated patients still face a dismal prognosis with a median survival below 15-18 months. Temozolomide (TMZ) is the main chemotherapeutic agent administered; however, intrinsic or acquired resistance to TMZ contributes to the limited efficacy of this drug. To circumvent the current drawbacks in GB treatment, a large number of classical and non-classical platinum complexes have been prepared and tested for anticancer activity, especially platinum (IV)-based prodrugs. Platinum complexes, used as alkylating agents in the anticancer chemotherapy of some malignancies, are though often associated with severe systemic toxicity (i.e., neurotoxicity), especially after long-term treatments. The objective of the current developments is to produce novel nanoformulations with improved lipophilicity and passive diffusion, promoting intracellular accumulation, while reducing toxicity and optimizing the concomitant treatment of chemo-/radiotherapy. Moreover, the blood-brain barrier (BBB) prevents the access of the drugs to the brain and accumulation in tumour cells, so it represents a key challenge for GB management. The development of novel nanomedicines with the ability to (i) encapsulate Pt-based drugs and pro-drugs, (ii) cross the BBB, and (iii) specifically target cancer cells represents a promising approach to increase the therapeutic effect of the anticancer drugs and reduce undesired side effects. In this review, a critical discussion is presented concerning different families of nanoparticles able to encapsulate platinum anticancer drugs and their application for GB treatment, emphasizing their potential for increasing the effectiveness of platinum-based drugs.

Nanomedicines in the treatment of colon cancer: a focus on metallodrugs

Worldwide, colon cancer (CC) represents the fourth most common type of cancer and the fifth major cause of cancer-associated deaths. Surgical resection is considered the standard therapeutic choice for CC in early stages. However, in latter stages of the disease, adjuvant chemotherapy is essential for an appropriate management of this pathology. Metal-based complexes displaying cytotoxic properties towards tumor cells emerge as potential chemotherapeutic options. One metallodrug, oxaliplatin, was already approved for clinical use, playing an important role in the treatment of CC patients. Unfortunately, most of the newly designed metal-based complexes exhibit lack of selectivity against cancer cells, low solubility and permeability, high dose-limiting toxicity, and emergence of resistances. Nanodelivery systems enable the incorporation of metallodrugs at adequate payloads, solving the above-referred drawbacks. Moreover, drug delivery systems, depending on their physicochemical properties, are able to release the incorporated material preferentially at affected tissues/organs, enhancing the therapeutic activity in vivo, with concomitant fewer side effects. In this review, the general features and therapeutic management of CC will be addressed, with a special focus on preclinical or clinical studies using metal-based compounds. Furthermore, the use of different nanodelivery systems will also be described as tools to potentiate the therapeutic index of metallodrugs for the management of CC.

Remodeling tumor microenvironment with nanomedicines

The tumor microenvironment (TME) has been recognized as a major contributor to cancer malignancy and therapeutic resistance. Thus, strategies directed to re-engineer the TME are emerging as promising approaches for improving the efficacy of antitumor therapies by enhancing tumor perfusion and drug delivery, as well as alleviating the immunosuppressive TME. In this regard, nanomedicine has shown great potential for developing effective treatments capable of re-modeling the TME by controlling drug action in a spatiotemporal manner and allowing long-lasting modulatory effects on the TME. Herein, we review recent progress on TME re-engineering by using nanomedicine, particularly focusing on formulations controlling TME characteristics through targeted interaction with cellular components of the TME. Importantly, the TME should be re-engineering to a quiescent phenotype rather than be destroyed. Finally, immediate challenges and future perspectives of TME-re-engineering nanomedicines are discussed, anticipating further innovation in this growing field. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Revisiting Platinum-Based Anticancer Drugs to Overcome Gliomas

Although there are many patients with brain tumors worldwide, there are numerous difficulties in overcoming brain tumors. Among brain tumors, glioblastoma, with a 5-year survival rate of 5.1%, is the most malignant. In addition to surgical operations, chemotherapy and radiotherapy are generally performed, but the patients have very limited options. Temozolomide is the most commonly prescribed drug for patients with glioblastoma. However, it is difficult to completely remove the tumor with this drug alone. Therefore, it is necessary to discuss the potential of anticancer drugs, other than temozolomide, against glioblastomas. Since the discovery of cisplatin, platinum-based drugs have become one of the leading chemotherapeutic drugs. Although many studies have reported the efficacy of platinum-based anticancer drugs against various carcinomas, studies on their effectiveness against brain tumors are insufficient. In this review, we elucidated the anticancer effects and advantages of platinum-based drugs used in brain tumors. In addition, the cases and limitations of the clinical application of platinum-based drugs are summarized. As a solution to overcome these obstacles, we emphasized the potential of a novel approach to increase the effectiveness of platinum-based drugs.

Basics to advances in nanotherapy of colorectal cancer

Colorectal cancer (CRC) is the third most common cancer existing across the globe. It begins with the formation of polyps leading to the development of metastasis, especially in advanced stage patients, who necessitate intensive chemotherapy that usually results in a poor response and high morbidity owing to multidrug resistance and severe untoward effects to the non-cancerous cells. Advancements in the targeted drug delivery permit the targeting of tumor cells without affecting the non-tumor cells. Various nanocarriers such as liposomes, polymeric nanoparticles, carbon nanotubes, micelles, and nanogels, etc. are being developed and explored for effective delivery of cytotoxic drugs to the target site thereby enhancing the drug distribution and bioavailability, simultaneously subduing the side effects. Moreover, immunotherapy for CRC is being explored for last few decades. Few clinical trials have even potentially benefited patients suffering from CRC, still immunotherapy persists merely an experimental alternative. Assessment of the ongoing and completed trials is to be warranted for effective treatment of CRC. Scientists are paying efforts to develop novel carrier systems that may enhance the targeting potential of low therapeutic index chemo- and immune-therapeutics. Several preclinical studies have revealed the superior efficacy of nanotherapy in CRC as compared to conventional approaches. Clinical trials are being recruited to ascertain the safety and efficacy of CRC therapies. The present review discourses in a nutshell the molecular interventions including the genetics, signaling pathways involved in CRC, and advances in various strategies explored for the treatment of CRC with a special emphasis on nanocarriers based drug targeting.

Ligand-Installed Nanocarriers toward Precision Therapy

Development of drug-delivery systems that selectively target neoplastic cells has been a major goal of nanomedicine. One major strategy for achieving this milestone is to install ligands on the surface of nanocarriers to enhance delivery to target tissues, as well as to enhance internalization of nanocarriers by target cells, which improves accuracy, efficacy, and ultimately enhances patient outcomes. Herein, recent advances regarding the development of ligand-installed nanocarriers are introduced and the effect of their design on biological performance is discussed. Besides academic achievements, progress on ligand-installed nanocarriers in clinical trials is presented, along with the challenges faced by these formulations. Lastly, the future perspectives of ligand-installed nanocarriers are discussed, with particular emphasis on their potential for emerging precision therapies.

Pharmacokinetics of nanotechnology-based formulations in pediatric populations

The development of therapeutics for pediatric use has advanced in the last few decades. However, off-label use of adult medications in pediatrics remains a significant clinical problem. Furthermore, the development of therapeutics for pediatrics is challenged by the lack of pharmacokinetic (PK) data in the pediatric population. To promote the development of therapeutics for pediatrics, the United States Pediatric Formulation Initiative recommended the investigation of nanotechnology-based delivery systems. Therefore, in this review, we provided comprehensive information on the PK of nanotechnology-based formulations from preclinical and clinical studies in pediatrics. Specifically, we discuss the relationship between formulation parameters of nanoformulations and PK of the encapsulated drug in the context of pediatrics. We review nanoformulations that include dendrimers, liposomes, polymeric long-acting injectables (LAIs), nanocrystals, inorganic nanoparticles, polymeric micelles, and protein nanoparticles. In addition, we describe the importance and need of PK modeling and simulation approaches used in predicting PK of nanoformulations for pediatric applications.

pH and redox dual-responsive copolymer micelles with surface charge reversal for co-delivery of all-trans-retinoic acid and paclitaxel for cancer combination chemotherapy

BACKGROUND

Co-delivery all-trans-retinoic acid (ATRA) and paclitaxel (PTX) is an effective strategy for cancer therapy. However, in many previous reported ATRA conjugated co-delivery systems, the ATRA was released slower than PTX, and the total drug release of ATRA far lower than that of PTX.

PURPOSE

We designed and prepared a pH and redox dual responsive drug delivery system (DA-ss-NPs) co-delivery ATRA and PTX for cancer therapy. The surface charge of DA-ss-NPs could change from negative to positive under tumor slightly acidic microenvironment, and both drugs could be quickly released from DA-ss-NPs under intracellular high concentration of glutathione (GSH).

METHODS

The DA-ss-NPs were constructed by encapsulating PTX into the hydrophobic core of the polymer micelles, in which the polymer was synthesized by conjugating ATRA and 2,3-Dimethylmalefic anhydride (DMA) on side chains of Cystamine dihydrochloride (Cys) modified PEG-b-PAsp (named DA-ss-NPs). The surface charge of DA-ss-NPs under different pH conditions were detected. And the drug release was also measured under different concentration of GSH. The therapeutic effect of DA-ss-NPs were investigated in Human lung cancer A549 cells and A549 tumor-bearing mice.

RESULTS

The zeta potential of DA-ss-NPs was -16.3 mV at pH 7.4, and which changed to 16 mV at pH 6.5. Cell uptake experiment showed that more DA-ss-NPs were internalized by A549 cells at pH 6.5 than that at pH 7.4. In addition, in presence of 10 mM GSH at pH 7.4, about 75%-85% ATRA was released from DA-ss-NPs within 48 h; but less than 20% ATRA was released without GSH. In vivo antitumor efficiency showed that the DA-ss-NPs could affectively inhibite the tumor in compared with control groups.

CONCLUSION

The charge-reversal and GSH-responsive DA-ss-NPs provide an excellent platform for potential tumor therapy.

Shape-Controlled Synthesis of Luminescent Hemoglobin Capped Hollow Porous Platinum Nanoclusters and their Application to Catalytic Oxygen Reduction and Cancer Imaging

Engineering hollow and porous platinum nanostructures using biomolecular templates is currently a significant focus for the enhancement of their facet-dependent optical, electronic, and electrocatalytic properties. However, remains a formidable challenge due to lack of appropriate biomolecules to have a structure-function relationship with nanocrystal facet development. Herein, human hemoglobin found to have facet-binding abilities that can control the morphology and optical properties of the platinum nanoclusters (Pt NCs) by regulation of the growth kinetics in alkaline media. Observations revealed the growth of unusual polyhedra by shape-directed nanocluster attachment along a certain orientation accompanied by Ostwald ripening and, in turn, yield well-dispersed hollow single-crystal nanotetrahedrons, which can easily self-aggregated and crystallized into porous and polycrystalline microspheres. The spontaneous, biobased organization of Pt NCs allow the intrinsic aggregation-induced emission (AIE) features in terms of the platinophilic interactions between Pt(II)-Hb complexes on the Pt(0) cores, thereby controlling the degree of aggregation and the luminescent intensity of Pt(0)@Pt(II)−Hb core−shell NCs. The Hb-Pt NCs exhibited high-performance electrocatalytic oxygen reduction providing a fundamental basis for outstanding catalytic enhancement of Hb-Pt catalysts based on morphology dependent and active site concentration for the four-electron reduction of oxygen. The as-prepared Hb-Pt NCs also exhibited high potential to use in cellular labeling and imaging thanks to the excellent photostability, chemical stability, and low cytotoxicity.

Co-administration of genistein with doxorubicin-loaded polypeptide nanoparticles weakens the metastasis of malignant prostate cancer by amplifying oxidative damage

Prostate cancer is a typical malignant disease with a high incidence and a poor prognosis. Doxorubicin hydrochloride (DOX·HCl) is one of the most effective agents in the treatment of prostate cancer, but severe side effects and metastasis after its treatment impose restrictions on its application. Herein, a combination of genistein (GEN) and doxorubicin-loaded polypeptide nanoparticles (DOX-NPs) is constructed for the treatment of prostate cancer. The DOX-NPs can reduce the side effects caused by free DOX·HCl and produce a relatively low level of intracellular reactive oxygen species (ROS)-induced oxidative damage, while GEN, an inhibitor of the oxidative DNA repair enzyme apurinic/apyrimidinic endonuclease1 (APE1), can further amplify the ROS-induced oxidative damage by downregulating the intracellular expression of APE1 and reducing oxidative DNA repair in the prostate cancer cells. Because high levels of ROS-induced oxidative damage can prevent the distant metastasis of tumor cells, the distant metastasis of malignant prostate cancer cells is significantly inhibited by the combination of genistein and DOX-NPs with amplified oxidative damage.

Celecoxib normalizes the tumor microenvironment and enhances small nanotherapeutics delivery to A549 tumors in nude mice

Barriers presented by the tumor microenvironment including the abnormal tumor vasculature and interstitial matrix invariably lead to heterogeneous distribution of nanotherapeutics. Inspired by the close association between cyclooxygenase-2 (COX-2) and tumor-associated angiogenesis, as well as tumor matrix formation, we proposed that tumor microenvironment normalization by COX-2 inhibitors might improve the distribution and efficacy of nanotherapeutics for solid tumors. The present study represents the first time that celecoxib, a special COX-2 inhibitor widely used in clinics, was explored to normalize the tumor microenvironment and to improve tumor nanotherapeutics delivery using a human-derived A549 tumor xenograft as the solid tumor model. Immunofluorescence staining of tumor slices demonstrated that oral celecoxib treatment at a dose of 200 mg/kg for two weeks successfully normalized the tumor microenvironment, including tumor-associated fibroblast reduction, fibronectin bundle disruption, tumor vessel normalization, and tumor perfusion improvement. Furthermore, it also significantly enhanced the in vivo accumulation and deep penetration of 22-nm micelles rather than 100-nm nanoparticles in tumor tissues by in vivo imaging and distribution experiments and improved the therapeutic efficacy of paclitaxel-loaded micelles in tumor xenograft-bearing mouse models in the pharmacodynamics experiment. As celecoxib is widely and safely used in clinics, our findings may have great potential in clinics to improve solid tumor treatment.

Enhanced anti-metastatic and anti-tumorigenic efficacy of Berbamine loaded lipid nanoparticles in vivo

Research on metastasis is gaining momentum for effective cancer management. Berbamine (BBM) has the potency to act as a therapeutic in multiple cancers and cancer metastasis. However, the major limitation of the compound includes poor bioavailability at the tumor site due to short plasma half-life. Here, our major objective involved development of lipid based nanoparticles (NPs) loaded with BBM with an aim to circumvent the above problem. Moreover its, therapeutic potentiality was evaluated through various in vitro cellular studies and in vivo melanoma primary and experimental lung metastatic tumor model in C57BL/6 mice. Results of different cellular experiments demonstrated enhanced therapeutic efficacy of BBM-NPs in inhibiting metastasis, cell proliferation and growth as compared to native BBM in highly metastatic cancer cell lines. Further, in vivo results demonstrated suppression of primary B16F10 melanoma tumor growth in C57BL/6 mice model treated with BBM-NPs than that of native BBM. Importantly, a moderately cytotoxic dose of BBM-NPs was able to significantly suppress the incidence of B16F10 cells lung metastasis in vivo. Results indicated development of an effective approach for aggressive metastatic cancer.

Treating breast cancer metastasis with cabazitaxel-loaded polymeric micelles

Cancer metastasis is the primary cause of high mortality in breast cancer patients. In this study, we loaded an anti-cancer drug, cabazitaxel (CTX), into polymeric micelles (CTX-loaded polymeric micelles, PCMs), and explored their therapeutic efficacy in breast cancer metastasis. The characteristics of PCMs were investigated, and their anti-metastatic efficacy was assessed using in vitro and in vivo evaluations. PCMs had an average diameter of 50.13±11.96 nm with a CTX encapsulation efficiency of 97.02%±0.97%. PCMs could be effectively internalized into metastatic 4T1 breast cancer cells in vitro. CTX (10 ng/mL) or an equivalent concentration in PCMs did not significantly affected the viability of 4T1 cells, but dramatically decreased the cell migration activities. In an orthotopic metastatic breast cancer model, intravenously administered PCMs could be efficiently delivered to the tumor sites, resulting in a 71.6% inhibition of tumor growth and a 93.5% reduction of lung metastases. Taken together, our results verify the anti-metastatic efficacy of PCMs, thus providing an encouraging strategy for treating breast cancer metastasis.

Nanomaterial-Enabled Cancer Therapy

While cancer remains the major cause of death worldwide, nanomaterial (NM)-based diagnosis and treatment modalities are showing remarkable potential to better tackle clinical oncology by effectively targeting therapeutic agents to tumors. NMs can selectively accumulate in solid tumors, and they can improve the bioavailability and reduce the toxicity of encapsulated cytotoxic agents. Additional noteworthy functions of NMs in cancer treatment include the delivery of contrast agents to image tumor sites, delivery of genetic materials for gene therapy, and co-delivery of multiple agents to achieve combination therapy or simultaneous diagnostic and therapeutic outcomes. Although several NM therapeutics have been successfully translated to clinical applications, the gap between the bench and the bedside remains ominously wide. Tumor heterogeneity and the disparity between pre-clinical and clinical studies have been identified as two of the major translational challenges of NM-based cancer therapies. Herein, we review a handful of recent research studies on the use of NMs in cancer therapy and imaging, with a limited discussion on the consequences of tumor heterogeneity and pre-clinical studies on translational research of NM-based delivery systems and propositions in the literature to overcome these challenges.

Investigation on the controlled synthesis and post-modification of poly-[(N-2-hydroxyethyl)-aspartamide]-based polymers

We report the controlled synthesis of PHEA-based polymers and enhanced the post-modification reactivity by reducing the intramolecular hydrogen bonding.

Exploiting developments in nanotechnology for the preferential delivery of platinum-based anti-cancer agents to tumours: targeting some of the hallmarks of cancer

Platinum drugs as anti-cancer therapeutics are held in extremely high regard. Despite their success, there are drawbacks associated with their use; their dose-limiting toxicity, their limited activity against an array of common cancers and patient resistance to Pt-based therapeutic regimes. Current investigations in medicinal inorganic chemistry strive to offset these shortcomings through selective targeting of Pt drugs and/or the development of Pt drugs with new or multiple modes of action. A comprehensive overview showcasing how liposomes, nanocapsules, polymers, dendrimers, nanoparticles and nanotubes may be employed as vehicles to selectively deliver cytotoxic Pt payloads to tumour cells is provided.

A pH-activatable nanoparticle with signal-amplification capabilities for non-invasive imaging of tumour malignancy

Engineered nanoparticles that respond to pathophysiological parameters, such as pH or redox potential, have been developed as contrast agents for the magnetic resonance imaging (MRI) of tumours. However, beyond anatomic assessment, contrast agents that can sense these pathological parameters and rapidly amplify their magnetic resonance signals are desirable because they could potentially be used to monitor the biological processes of tumours and improve cancer diagnosis. Here, we report an MRI contrast agent that rapidly amplifies magnetic resonance signals in response to pH. We confined Mn(2+) within pH-sensitive calcium phosphate (CaP) nanoparticles comprising a poly(ethylene glycol) shell. At a low pH, such as in solid tumours, the CaP disintegrates and releases Mn(2+) ions. Binding to proteins increases the relaxivity of Mn(2+) and enhances the contrast. We show that these nanoparticles could rapidly and selectively brighten solid tumours, identify hypoxic regions within the tumour mass and detect invisible millimetre-sized metastatic tumours in the liver.

Development of polymeric micelles for targeting intractable cancers

In relation to recent advances in nanobiotechnologies, cancer-targeted therapy using nano-scaled drug carriers (nanocarriers) has been attracting enormous attention with success in clinical studies. Polymeric micelles, core-shell-type nanoparticles formed through the self-assembly of block copolymers, are one of the most promising nanocarrier, because their critical features such as size, stability, and drug incorporation efficiency and release rate can be modulated by designing the constituent block copolymers. The utilities of polymeric micelles have been reported not only in experimental tumor models in mice but also in clinical studies. In this article, we aim to explain the rationale of designing polymeric micelles for targeting intractable cancers such as pancreatic cancer, glioblastoma, and metastases. Also, we review recent progress in clinical studies on polymeric micelles incorporating anticancer drugs. In addition, we introduce the next generation of polymeric micelles as the platform integrated with smart functionalities such as targetability, environmental sensitivity, and imaging properties. Thus, polymeric micelles can realize safe and effective cancer therapy, and offer tailor-made medicines for individual patients.

Polymeric nanoparticles: the future of nanomedicine

Polymeric nanoparticles (NPs) are one of the most studied organic strategies for nanomedicine. Intense interest lies in the potential of polymeric NPs to revolutionize modern medicine. To determine the ideal nanosystem for more effective and distinctly targeted delivery of therapeutic applications, particle size, morphology, material choice, and processing techniques are all research areas of interest. Utilizations of polymeric NPs include drug delivery techniques such as conjugation and entrapment of drugs, prodrugs, stimuli-responsive systems, imaging modalities, and theranostics. Cancer, neurodegenerative disorders, and cardiovascular diseases are fields impacted by NP technologies that push scientific boundaries to the leading edge of transformative advances for nanomedicine.

A new approach to reduce toxicities and to improve bioavailabilities of platinum-containing anti-cancer nanodrugs

Platinum (Pt) drugs are the most potent and commonly used anti-cancer chemotherapeutics. Nanoformulation of Pt drugs has the potential to improve the delivery to tumors and reduce toxic side effects. A major challenge for translating nanodrugs to clinical settings is their rapid clearance by the reticuloendothelial system (RES), hence increasing toxicities on off-target organs and reducing efficacy. We are reporting that an FDA approved parenteral nutrition source, Intralipid 20%, can help this problem. A dichloro (1, 2-diaminocyclohexane) platinum (II)-loaded and hyaluronic acid polymer-coated nanoparticle (DACHPt/HANP) is used in this study. A single dose of Intralipid (2 g/kg, clinical dosage) is administrated [intravenously (i. v.), clinical route] one hour before i.v. injection of DACHPt/HANP. This treatment can significantly reduce the toxicities of DACHPt/HANP in liver, spleen, and, interestingly, kidney. Intralipid can decrease Pt accumulation in the liver, spleen, and kidney by 20.4%, 42.5%, and 31.2% at 24-hr post nanodrug administration, respectively. The bioavailability of DACHPt/HANP increases by 18.7% and 9.4% during the first 5 and 24 hr, respectively.

Polymeric biomaterials for the delivery of platinum-based anticancer drugs

Since cisplatin, cis-diamminedichloroplatinum(ii), received FDA approval for use in cancer treatment in 1978, platinum-based drugs have been one of the most widely used drugs for the treatment of tumors in testicles, ovaries, head and neck. However, there are concerns associated with the use of platinum-based anticancer drugs, owing to severe side effects and drug resistance. In order to overcome these limitations, various drug-delivery systems have been developed based on diverse organic and inorganic materials. In particular, the versatility of polymeric materials facilitates the tuning of drug-delivery systems to meet their primary goals. This review focuses on the progress made over the last five years in the application of polymeric nanoparticles for the delivery of platinum-based anticancer drugs. The present article not only describes the fundamental principles underlying the implementation of polymeric nanomaterials in platinum-based drug delivery, but also summarizes concepts and strategies employed in the development of drug-delivery systems.

Mesoporous silica nanoparticles for 19F magnetic resonance imaging, fluorescence imaging, and drug delivery

Multifunctional mesoporous silica nanoparticles (MSNs) are good candidates for multimodal applications in drug delivery, bioimaging, and cell targeting. In particular, controlled release of drugs from MSN pores constitutes one of the superior features of MSNs. In this study, a novel drug delivery carrier based on MSNs, which encapsulated highly sensitive 19F magnetic resonance imaging (MRI) contrast agents inside MSNs, was developed. The nanoparticles were labeled with fluorescent dyes and functionalized with small molecule-based ligands for active targeting. This drug delivery system facilitated the monitoring of the biodistribution of the drug carrier by dual modal imaging (NIR/19F MRI). Furthermore, we demonstrated targeted drug delivery and cellular imaging by the conjugation of nanoparticles with folic acid. An anticancer drug (doxorubicin, DOX) was loaded in the pores of folate-functionalized MSNs for intracellular drug delivery. The release rates of DOX from the nanoparticles increased under acidic conditions, and were favorable for controlled drug release to cancer cells. Our results suggested that MSNs may serve as promising 19F MRI-traceable drug carriers for application in cancer therapy and bio-imaging.