Calcium Phosphate Nanocarriers Research Articles

Preparation and application of calcium phosphate nanocarriers in drug delivery.

Calcium phosphate nanoparticles represent promising materials for drug delivery because of its favorable properties, including biocompatibility, biodegradability and strong affinity for binding to nucleic acids (pDNA, siRNA, miRNA, etc.) and therapeutic drugs (cisplatin, carboplatin, paclitaxel, gefitinib, doxorubicin, etc.). Various strategies to prepare the size-controllable, stable, targeting and pH-responsive CaP nanocarriers have been extensively developed as the potential candidates in clinic. This review discusses the mostly recent developments in the design of calcium phosphate nanocarriers as drug delivery systems and therapeutic agents. Additionally, the advantage is unquestionably demonstrated and the obstacles are thoroughly examined in order to overcome future clinical issues.

Preparation and functional study of pH-sensitive amorphous calcium phosphate nanocarriers

Schematic presentation of synthetic procedure of HA-FCNs (a) and HA-FCNs/ACP (b). • The great prospects in cancer treatment of multifunctional nanoparticles. • pH responsive drug release behavior and excellent biocompatibility. • Targeted into human lung cancer cells (A549 cells). • Stronger fluorescence signals. Recently, multifunctional nanoparticles have shown great prospects in cancer treatment, which have the ability to simultaneously deliver the drug, image and target tumor cells. In this paper, we designed a luminescent nanoparticles platform based on hydrothermal hyaluronic acid/amorphous calcium phosphate (HA-FCNs/ACP) with multifunctional properties for drug delivery, bio-imaging, and targeting treatment. HA-FCNs/ACP shows an ability to load curcumin (Cur) with pH-sensitive responsive drug release behavior and excellent biocompatibility. HA-FCNs/ACP dispersed in the cytoplasm through the overexpressed CD44 receptor that is actively targeted into human lung cancer cells (A549 cells). Meanwhile, the viability of A549 cells was significantly inhibited in vitro . The prepared HA-FCNs and HA-FCNs/ACP both exhibit excellent targeted bioimaging performance on cancer cells. Hence, the as-prepared nanoparticles have promising applications in treating tumor disease.

Synergistic Combination of Calcium and Citrate in Mesoporous Nanoparticles Targets Pleural Tumors

Summary Conventional chemotherapy leads to severe adverse effects since it involves systemic administration of toxic drugs at high dosage. Unlike traditional chemotherapeutics, calcium phosphate and citrate have both been discussed as very promising anticancer agents and are not inherently toxic. Yet, their breakthrough has been hampered by the lack of an administration approach that overcomes the strict regulatory mechanisms of the cell. Here, we present a combinatorial administration of calcium, phosphate, and citrate as colloidal, amorphous nanoparticles (CPCs) that selectively kill cancer cells without involvement of inherently toxic drugs. The particles are toxic neither before endosomal release nor after their degradation. This highly selective toxicity allowed us to successfully treat two different aggressive pleural tumors in mice, reducing their size by about 40% and 70% after only two local applications. Safety assessment studies over 2 months show no signs of adverse effects except for slightly enhanced pleural thickening after eight applications.

Calcium phosphate nanocarriers for drug delivery to tumors: imaging, therapy and theranostics.

Calcium phosphate (CaP) was engineered as a drug delivery nanocarrier nearly 50 years ago due to its biocompatibility and biodegradability. In recent years, several approaches have been developed for the preparation of size-controllable, stable and multifunctional CaP nanocarriers, and several targeting moieties have also been decorated on the surface of these nanocarriers for active targeting. The CaP nanocarriers have been utilized for loading probes, nucleic acids, anticancer drugs and photosensitizers for cancer imaging, therapy and theranostics. Herein, we reviewed the recent advances in the preparation strategies of CaP nanocarriers and the applications of these nanocarriers in tumor diagnosis, gene delivery, drug delivery and theranostics and finally provided perspectives.

Enhanced antineoplastic/therapeutic efficacy using 5-fluorouracil-loaded calcium phosphate nanoparticles.

In the past few decades, the successful theranostic application of nanomaterials in drug delivery systems has significantly improved the antineoplastic potency of conventional anticancer therapy. Several mechanistic advantages of nanomaterials, such as enhanced permeability, retention, and low toxicity, as well as surface engineering with targeting moieties, can be used as a tool in enhancing the therapeutic efficacy of current approaches. Inorganic calcium phosphate nanoparticles have the potential to increase the therapeutic potential of antiproliferative drugs due to their excellent loading efficiency, biodegradable nature and controlled-release behaviour. Herein, we report a novel system of 5-fluorouracil (5-FU)-loaded calcium phosphate nanoparticles (CaP@5-FU NPs) synthesized via a reverse micelle method. The formation of monodispersed, spherical, crystalline nanoparticles with an approximate diameter of 160–180 nm was confirmed by different methods. The physicochemical characterization of the synthesized CaP@5-FU NPs was done with transmission electron microscopy (TEM), dynamic light scattering (DLS), field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The antineoplastic potential of the CaP@5-FU NPs against colorectal and lung cancer cells was reported. The CaP@5-FU NPs were found to inhibit half the population (IC50) of lung adenocarcinoma (A549) cells at 32 μg/mL and colorectal (HCT-15) cancer cells at 48.5 μg/mL treatment. The apoptotic induction of CaP@5-FU NPs was confirmed with acridine orange/ethidium bromide (AO/EB) staining and by examining the morphological changes with Hoechst and rhodamine B staining in a time-dependent manner. The apparent membrane bleb formation was observed in FE-SEM micrographs. The up-regulated proapoptotic and down-regulated antiapoptotic gene expressions were further confirmed with semiquantitative reverse transcriptase polymerase chain reaction (PCR). The increased intracellular reactive oxygen species (ROS) were quantified via flow cytometry upon CaP@5-FU NP treatment. Likewise, the cell cycle analysis was performed to confirm the enhanced apoptotic induction. Our study concludes that the calcium phosphate nanocarriers system, i.e. CaP@5-FU NPs, has higher antineoplastic potential as compared to 5-FU alone and can be used as an improved alternative to the antimitotic drug, which causes severe side effects when administrated alone.

Bioinspired negatively charged calcium phosphate nanocarriers for cardiac delivery of MicroRNAs.

To develop biocompatible and bioresorbable negatively charged calcium phosphate nanoparticles (CaP-NPs) as an innovative therapeutic system for the delivery of bioactive molecules to the heart. CaP-NPs were synthesized via a straightforward one-pot biomineralization-inspired protocol employing citrate as a stabilizing agent and regulator of crystal growth. CaP-NPs were administered to cardiac cells in vitro and effects of treatments were assessed. CaP-NPs were administered in vivo and delivery of microRNAs was evaluated. CaP-NPs efficiently internalized into cardiomyocytes without promoting toxicity or interfering with any functional properties. CaP-NPs successfully encapsulated synthetic microRNAs, which were efficiently delivered into cardiac cells in vitro and in vivo. CaP-NPs are a safe and efficient drug-delivery system for potential therapeutic treatments of polarized cells such as cardiomyocytes.

Bio-inspired negatively-charged calcium phosphate nanocarriers for cardiac delivery of therapeutic molecules

Event Abstract Back to Event Bio-inspired negatively-charged calcium phosphate nanocarriers for cardiac delivery of therapeutic molecules Michele Iafisco1, Vittoria Di Mauro2, 3, Nicolò Salvarani2, 3, Gloria Belén Ramírez-Rodríguez1, Tatiana Patrício1, Michele Miragoli2, 3, Daniele Catalucci2, 3 and Anna Tampieri1 1 National Research Council (CNR), Institute of Science and Technology for Ceramics (ISTEC), Italy 2 Humanitas Clinical and Research Center, Italy 3 National Research Council (CNR), Institute of Genetics and Biomedical Research (IRGB), Italy Cardiovascular disease (CVD) is a worldwide growing problem that afflicts close to 1% of the population and causes 17.3 million annual premature deaths. Causes include ischemic, toxic, genetic, post-inflammatory, and structural defects, overall resulting in a mortality of ~50% within 5 years from diagnosis[1]. Clinical management of CVDs has improved during the last decades, but despite significant advancements, these pathologies still lead to a poor quality of life and reduced longevity. Therefore, a great challenge is the identification of innovative therapeutic compounds and the development of more efficient, safe, and “patient-friendly” drug-delivery systems. Nanoparticles (NPs) hold great promise for nanomedical systems and provide an alternative strategy for more efficient, controlled, and safe approaches of drug delivery[2]. While largely investigated in the cancer field, the development and use of efficient NPs for the treatment of CVDs is still in its infancy. In fact, to the best of our knowledge, only liposomes or NPs based on synthetic polymers have been investigated so far for the delivery of various therapeutic molecules to myocardial cells[3],[4]. Their use is drastically limited due to the lack of biodegradability and biocompatibility of these kinds of nano-carriers, the uncontrolled drug release in the bloodstream, the poor encapsulation efficacy, and the poor stability. In summary, there is a strong need for the identification of new formulations based on biocompatible and biodegradable NPs to overcome the limitations of NPs currently used for CVD treatment. In this study, novel biocompatible and bioresorbable negatively charged biodegradable calcium phosphate nanoparticles (CaP-NPs) were developed as an innovative therapeutic system for the delivery of bioactive molecules to the heart. Synthesis of CaP-NPs was performed according to a new, straightforward one-pot inspired biomineralization protocol employing citrate as a stabilizing agent and regulator of crystal growth. Via the classical clathrin-mediated path, CaP-NPs were shown to efficiently internalize into HL-1 cardiac cells without promoting toxicity. Additionally, acute and chronic administration of CaP-NPs did not interfere with Ca2+ handling properties and electrophysiological features of HL-1 cells and adult cardiomyocytes. Finally, preliminary experiments validated that CaP-NPs were successfully able to encapsulate bioactive synthetic microRNAs and mimetic peptides, which were efficiently delivered into cardiac cell line in vitro and surprisingly even into cardiac tissue when admistered in vivo. To sum up, our results showed that the CaP-NPs generated in this work are safe and effective drug-delivery systems for a new potential therapeutic treatment of polarized cells such as cardiomyocytes. The Italian Flagship Project NANOMAX – miRnano (Progetto Bandiera MIUR PNR 2011–2013)

Electrosprayed calcium phosphate nano-carriers as therapeutic agents

Event Abstract Back to Event Electrosprayed calcium phosphate nano-carriers as therapeutic agents Yogeshwar Chakrapani1, 2, Sampath T. Kumar1, Kumary T. V2 and Deepa K. Raj2 1 Indian Institute of Technology Madras, Medical Materials Laboratory, India 2 Sree Chitra Tirunal Institute for Medical Sciences and Technology, Tissue Culture Laboratory, India Introduction: Calcium phosphate particles intended as bone fillers and drug delivery agents are gaining interest worldwide. Size of the particles becomes an important factor when they are intended to act as site specific delivery agents, for therapeutic purposes. Cellular uptake, velocity of drug carrier in physiological pathways and specificity towards binding of therapeutic molecules are some key parameters that are greatly influenced by particle size[1]. The aim of the current study was to produce calcium phosphate particles through a modified electrospraying process[2]; characterize them physicochemically, evaluate their cytocompatibility and to analyse the efficacy of the particles to act as drug delivery systems. Materials and Methods: Calcium nitrate tetrahydrate (CNt) and triethyl phosphite (TEP) were used as the calcium and phosphorous precursors with an aqueous solvent. Sols with the required Ca/P ratio (1.67 & 1.61) were prepared by adding CNt solution drop wise to the hydrolysed TEP solution. The obtained sols were aged and subsequently blended with a polyvinylalcohol solution. The solution was loaded into a 10ml syringe fitted with an 18G blunted needle. The tip to collector distance, flow rate and voltage were optimised for electrospraying. The as sprayed particles were dried overnight and then subjected to a controlled heating upto 500˚C. The particles obtained on heating 1day and 5days aged sols of 1.67 and 1.61 Ca/P ratio will be referred to as CaP167-1d, CaP167-5d, CaP161-1d and CaP161-5d respectively. Phase confirmation was done through X-ray diffraction (XRD). Stability of phases was tested by heating upto 900˚C. The particles size and morphology were analysed using transmission electron microscopy (TEM). In vitro biological evaluation of the particles were performed using L-929 and HOS cell lines. The drug delivering capacities of the particles were assessed using tetracycline as model drug. Results and Discussion: Figure 1 shows the results of XRD and TEM analysis. XRD patterns were matched with that of hydroxyapatite (JCPDS file no. 9-432). At 500˚C the patterns of all the particles are similar whereas on heating to 900˚C, CaP167-1d and 5d are the same while CaP161-1d and 5d develop peaks of β-tricalcium phosphate. From TEM imaging it is evident that increasing the aging time of sols has lead to an increase in the electrosprayed particle size. MTT assay confirms the non cytotoxic nature of the particles (Fig. 2a). Cell adhesion and proliferation on the surface of pelletized particles confirms the biocompatibility (Fig. 2b). Cellular uptake studies confirm the potential of the particles to act as therapeutic delivery agents. The loading and release profiles reveal that particles with a CaP ratio of 1.61 show a higher loading but a lesser release when compared to those with a CaP ratio of 1.67. Also smaller particles show a better loading and release profiles than their larger size counterparts. Conclusion: In conclusion, a modified electrospraying process has been used to produce HA and CDHA particles in different size regimes. The particles do not elicit any toxicity and are readily taken up by the cells. Thus,electrosprayed CaP particles with controllable sizes are valid candidates for targeted delivery of therapeutic agents.The process opens up avenues for producing other ceramic particles as well. Dr. H. K. Varma, Bioceramics Laboratory, SCTIMST

Dual mode antibacterial activity of ion substituted calcium phosphate nanocarriers for bone infections.

Nanotechnology has tremendous potential for the management of infectious diseases caused by multi-drug resistant bacteria, through the development of newer antibacterial materials and efficient modes of antibiotic delivery. Calcium phosphate (CaP) bioceramics are commonly used as bone substitutes due to their similarity to bone mineral and are widely researched upon for the treatment of bone infections associated with bone loss. CaPs can be used as local antibiotic delivery agents for bone infections and can be substituted with antibacterial ions in their crystal structure to have a wide spectrum, sustained antibacterial activity even against drug resistant bacteria. In the present work, a dual mode antibiotic delivery system with antibacterial ion substituted calcium deficient hydroxyapatite (CDHA) nanoparticles has been developed. Antibacterial ions such as zinc, silver, and strontium have been incorporated into CDHA at concentrations of 6, 0.25–0.75, and 2.5–7.5 at. %, respectively. The samples were found to be phase pure, acicular nanoparticles of length 40–50 nm and width 5–6 nm approximately. The loading and release profile of doxycycline, a commonly used antibiotic, was studied from the nanocarriers. The drug release was studied for 5 days and the release profile was influenced by the ion concentrations. The release of antibacterial ions was studied over a period of 21 days. The ion substituted CDHA samples were tested for antibacterial efficacy on Staphylococcus aureus and Escherichia coli by MIC/MBC studies and time-kill assay. AgCDHA and ZnCDHA showed high antibacterial activity against both bacteria, while SrCDHA was weakly active against S. aureus. Present study shows that the antibiotic release can provide the initial high antibacterial activity, and the sustained ion release can provide a long-term antibacterial activity. Such dual mode antibiotic and antibacterial ion release offers an efficient and potent way to treat an incumbent drug resistant infection.

Antiarthritic and Chondroprotective Activity of Lakshadi Guggul in Novel Alginate-Enclosed Chitosan Calcium Phosphate Nanocarriers

This study aimed to evaluate the antiarthritic and chondroprotective potentials of Lakshadi Guggul (LG) and Cissus quadrangularis encapsulated in novel alginate-enclosed chitosan-calcium phosphate nanocarriers (NCs) both in vitro in primary human chondrocytes and in vivo in mice with collagen-induced arthritis. Chondrocytes exposed to IL-1β and osteoarthritis chondrocytes grown in an ex vivo inflammation-based coculture were incubated with different concentrations of herbals, and cell modulatory activities were determined. For in vivo studies, herbals and their encapsulated nanoformulations were administered orally to DBA/1 mice with collagen-induced arthritis. C. quadrangularis and LG showed enhanced chondroprotective and proliferative activity in IL-1β-exposed primary chondrocytes, with LG showing the highest therapeutic potency. LG increased viability, proliferative and mitogenic activity, and inhibited cell apoptosis and mitochondrial depolarization. In vivo studies with LG and alginate-enclosed chitosan-calcium phosphate LG NCs revealed cartilage regenerative activity in those administered with the nanoformulation. The NCs were nontoxic to mice, reduced joint swelling and paw volume, and inhibited gene expression of MMPs and cytokines. The promising results from this study reveal, for the first time, the novel polymeric NC encapsulating LG as a potential therapeutic for rheumatic diseases.

A Mini Review of Biodegradable Calcium Phosphate Nanoparticles for Gene Delivery

Nucleic acid drugs are promising new therapeutics for the treatment of various diseases including genetic diseases, viral diseases, and cancer. However, their poor intracellular bioavailability and rapid degradation hinder their development as drugs. Therefore, the main challenge is to develop an efficient delivery system. Calcium phosphate has been widely used to transfect cultured cells for 40 years, due to its safety, simply of production and noticeable efficacy of transfection. Unfortunately, calcium phosphate particles show poor colloidal stability because of uncontrolled growth, which impedes their practical use. Recently, investigators have designed a variety of biodegradable calcium phosphate nanocarriers and achieved efficient gene delivery both in vitro and in vivo with low toxicity. In this review, we focus on the current research activity in the development of calcium phosphate nanoparticlss for gene delivery. Calcium phosphate nanoparticles are mainly classified into lipid coated and polymer coated ones for discussion. In addition, cellular uptake and intracellular trafficking of calcium phosphate nanoparticles are also mentioned.

Effect of Structure and Composition on Ibuprofen Drug Delivery by Calcium Phosphate Nanocarriers

The effect of structure and composition of calcium phosphate (CaP) nanoparticles namely hydroxyapatite (HA), calcium deficient hydroxyapatite (CDHA) with Ca/P ratio ranging from 1.33 to 1.61 and tricalcium phosphate (β-TCP), on the efficiency of nanoparticles as an ideal drug carrier have been investigated. Ibuprofen, an anti-inflammatory drug was chosen for this study. The CaP nanoparticles were prepared by microwave accelerated wet chemical synthesis method and were characterized by X-ray powder diffraction, infrared spectroscopy, and electron microscopic techniques. The loading and release profiles of ibuprofen from the nanocarriers was studied using UV-Vis spectroscopy. Maximum loading of the drug was observed in β-TCP (75%) followed by CDHA of Ca/P ratio 1.5. Both samples have same Ca/P ratio but have different crystal structure. Low amount of drug loading was observed in HA and other CDHAs which have Ca/P ratio different from 1.5. Although, all the samples exhibits sustained release of ibuprofen for about 7 days, the maximum release was also shown by β-TCP (26%). Among HA and CDHAs, the amount of ibuprofen release increases with increasing Ca/P ratio. The loading and release profile of ibuprofen drug seems to be strongly related to the Ca/P ratio and structure of CaP nanocarriers.

Calcium Phosphate Nanocarriers Dual‐Loaded with Bovine Serum Albumin and Ibuprofen: Facile Synthesis, Sequential Drug Loading and Sustained Drug Release

A simple and green strategy is reported for the preparation, drug loading, and release properties of a drug delivery system consisting of calcium phosphate (CP) nanocarriers dual-loaded with bovine serum albumin (BSA) and hydrophobic drug ibuprofen (IBU). The sequential loading of BSA and IBU in calcium phosphate nanocarriers and in vitro simultaneous release of BSA and IBU are realized and investigated. In this method, BSA, which is used as a model protein drug, is encapsulated in situ in calcium phosphate nanocarriers. Subsequently, the typical hydrophobic drug IBU is loaded in the BSA/CP drug delivery system, forming the IBU/BSA/CP dual drug delivery system. The experiments reveal that the preloaded BSA not only reduces the cytotoxicity of calcium phosphate nanocarriers but also significantly improves the IBU drug loading capacity in calcium phosphate nanocarriers and greatly extends the duration of drug release. Thus, the as-prepared IBU/BSA/CP dual drug delivery system is promising for drug delivery applications.

Reverse micelle-mediated synthesis of calcium phosphate nanocarriers for controlled release of bovine serum albumin

Calcium phosphate (CaP) nanoparticles with a calcium to phosphorus (Ca:P) molar ratio of 1.5:1 were synthesized using reverse microemulsion. Ca(NO 3) 2·4H 2O and H 3PO 4 were used as the aqueous phase, cyclohexane as the organic phase and poly(oxyethylene) 12 nonylphenol ether (NP-12) as the surfactant. Depending on the calcination temperature between 600 and 800 °C, CaP nanoparticle showed different phases of calcium-deficient hydroxyapatite (CDHA) and β-tricalcium phosphate (β-TCP), particle size between 48 and 69 nm, and a BET specific average surface area between 73 and 57 m 2 g −1. Bovine serum albumin (BSA) was used as a model protein to study loading and release behavior. The adsorptive property of BSA was investigated by the change in BET surface area of these nanoparticles and the pH of the suspension. At pH 7.5, the maximum amount of BSA was adsorbed onto CaP nanoparticle. The release kinetics of BSA showed a gradual time-dependent increase in pH 4.0 and 6.0 buffer solutions. However, the amount of protein released was significantly smaller at pH 7.2. The BSA release rate also varied depending on the presence of different phases of CaPs in the system, β-TCP or CDHA. These results suggest that the BSA protein release rate can be controlled by changing the particle size, surface area and phase composition of the CaP nanocarriers.