Preparation of pH-sensitive CaP nanoparticles coated with a phosphate-based block copolymer for efficient gene delivery

A Valid Bisphosphonate Modified Calcium Phosphate-Based Gene Delivery System: Increased Stability and Enhanced Transfection Efficiency In Vitro and In Vivo

Calcium phosphate (CaP) nanoparticles, as a promising vehicle for gene delivery, have been widely used owing to their biocompatibility, biodegradability and adsorptive capacity for nucleic acids. Unfortunately, their utility in vivo has been profoundly restricted due to numerous technical barriers such as the lack of tissue specificity and limited transfection efficiency, as well as uncontrollable aggregation over time. To address these issues, an effective conjugate folate-polyethylene glycol-pamidronate (shortened as FA-PEG-Pam) was designed and coated on the surface of CaP/NLS/pDNA (CaP/NDs), forming a versatile gene carrier FA-PEG-Pam/CaP/NDs. Inclusion of FA-PEG-Pam significantly reduced the size of CaP nanoparticles, thus inhibiting the aggregation of CaP nanoparticles. FA-PEG-Pam/CaP/NDs showed better cellular uptake than mPEG-Pam/CaP/NDs, which could be attributed to the high-affinity interactions between FA and highly expressed FR. Meanwhile, FA-PEG-Pam/CaP/NDs had low cytotoxicity and desired effect on inducing apoptosis (71.1%). Furthermore, FA-PEG-Pam/CaP/NDs showed admirable transfection efficiency (63.5%) due to the presence of NLS peptides. What’s more, in vivo studies revealed that the hybrid nanoparticles had supreme antitumor activity (IR% = 58.7%) among the whole preparations. Altogether, FA-PEG-Pam/CaP/NDs was expected to be a hopeful strategy for gene delivery.

Calcium-Binding Polymer-Coated Poly(lactide- co-glycolide) Microparticles for Sustained Release of Quorum Sensing Inhibitors to Prevent Biofilm Formation on Hydroxyapatite Surfaces

Quorum sensing (QS) inhibitor-based therapy is an attractive strategy to inhibit bacterial biofilm formation without excessive induction of antibiotic resistance. Thus, we designed Ca²⁺-binding poly(lactide- co-glycolide) (PLGA) microparticles that can maintain a sufficient concentration of QS inhibitors around hydroxyapatite (HA) surfaces in order to prevent biofilm formation on HA-based dental or bone tissues or implants and, therefore, subsequent pathogenesis. Poly(butyl methacrylate- co-methacryloyloxyethyl phosphate) (PBMP) contains both Ca²⁺-binding phosphomonoester groups and PLGA-interacting butyl groups. The PBMP-coated PLGA (PLGA/PBMP) microparticles exhibited superior adhesion to HA surfaces without altering the sustained release properties of uncoated PLGA microparticles. PLGA/PBMP microparticle-encapsulating furanone C-30, a representative QS inhibitor, effectively inhibited the growth of Streptococcus mutans and its ability to form biofilms on HA surface for prolonged periods of up to 100 h, which was much longer than either furanone C-30 in its free form or when encapsulated in noncoated PLGA microparticles.

Investigation of the Genotoxicity of Aluminum Oxide, β-Tricalcium Phosphate, and Zinc Oxide Nanoparticles In Vitro

The aim of this study was to investigate the genotoxicity of aluminum oxide (Al₂O₃), β-tricalcium phosphate (β-TCP) (Ca₃(PO₄)₂), and zinc oxide (ZnO) nanoparticles (NPs) that were 4.175, 9.058, and 19.8 nm sized, respectively, on human peripheral blood lymphocytes using micronucleus (MN) and chromosome aberration (CA) techniques. Aluminum oxide and β-TCP NPs did not show genotoxic effects on human peripheral blood cultures in vitro, even at the highest concentrations; therefore, these materials may be suitable for use as biocompatible materials. It was observed that, even at a very low dose (≥12.5 ppm), ZnO NPs had led to genotoxicity. In addition, at high concentrations (500 ppm and above), ZnO NPs caused mortality of lymphocytes. For these reasons, it was concluded that ZnO NPs are not appropriate for using as a biocompatible biomaterial.

Self-assembled CaP-based hybrid nanoparticles to enhance gene transfection efficiency in vitro and in vivo: beneficial utilization of PEGylated bisphosphate and nucleus locating signal

Calcium phosphate (CaP) nanoparticles have been considered as a non-viral gene delivery vehicle, but the weakness of inconsistent and low transfection efficiencies is limited to its progress.

Organic metal complexes based on zoledronate–calcium: a potential pDNA delivery system

Organic metal complexes as a type of hybrid materials have been used for gene delivery.

Preparation of CaP/pDNA nanoparticles by reverse micro-emulsion method: Optimization of formulation variables using experimental design

In this study, the CaP/pDNA nanoparticles were prepared using Triton X-100/Butanol/Cyclohexane/Water reverse microemulsion system. Optimization of preparation conditions was based on evaluation of particle size by Box–Behnken design method. The particle sizes of the optimized CaP/pDNA nanoparticles were found to be 60.23 ± 4.72 nm, polydispersity index was 0.252 and pDNA encapsulate efficiency was more than 90%. The optimized CaP/pDNA nanoparticles have pH sensitivity and biocompatibility. Further, optimized CaP/pDNA nanoparticles showed higher transfection efficiency.

An insight into functionalized calcium based inorganic nanomaterials in biomedicine: Trends and transitions

Over the recent years the use of biocompatible and biodegradable nanoparticles in biomedicine has become a significant priority. Calcium based ceramic nanoparticles like calcium phosphate (CaP) and calcium carbonate (CaCO3) are therefore considered as attractive carriers as they are naturally present in human body with nanosize range. Their application in tissue engineering and localized controlled delivery of bioactives for bones and teeth is well established now, but recently their use has increased significantly as carrier of bioactives through other routes also. These delivery systems have become most potential alternatives to other commonly used delivery system because of their cost effectiveness, biodegradability, chemical stability, controlled and stimuli responsive behaviour. This review comprehensively covers their characteristic features, method of preparation and applications but the thrust is to focus their recent development, functionalization and use in systemic delivery. On the same platform mineralization of other nanoparticulate delivery system which has widened their application drug delivery will be discussed. The emphasis has been given on their pH dependent properties which make them excellent carriers for tumour targeting and intracellular delivery. Finally this review also attempts to discuss their drawback which limits their clinical utility.

Inorganic nanovectors for nucleic acid delivery

Nucleic acids show immense potential to treat cancer, acquired immune deficiency syndrome, neurological diseases and other incurable human diseases. Upon systemic administration, they encounter a series of barriers and hence barely reach the site of action, the cell. Intracellular delivery of nucleic acids is facilitated by nanovectors, both viral and non-viral. A major advantage of non-viral vectors over viral vectors is safety. Nanovectors evaluated specifically for nucleic acid delivery include polyplexes, lipoplexes and other cationic carrier-based vectors. However, more recently there is an increased interest in inorganic nanovectors for nucleic acid delivery. Nevertheless, there is no comprehensive review on the subject. The present review would cover in detail specific properties and types of inorganic nanovectors, their preparation techniques and various biomedical applications as therapeutics, diagnostics and theranostics. Future prospects are also suggested.

Protamine sulfate-calcium carbonate-plasmid DNA ternary nanoparticles for efficient gene delivery

Ternary nanoparticles, protamine sulfate-calcium carbonate-plasmid DNA (PS-CaCO3-DNA), were prepared for efficient gene delivery. By adding the cationic polypeptide PS in the co-precipitation system of calcium carbonate and DNA, PS-CaCO3-DNA nanoparticles could be formed by self-assembly facilely. The effect of PS on the properties of the ternary nanoparticles was studied by varying the PS amount in the nanoparticles. The size and ζ-potential measurements indicated that the ternary nanoparticles with an appropriate PS amount exhibited a decreased size and an increased ζ-potential. The in vitro gene transfections mediated by different nanoparticles in 293T cells and HeLa cells were carried out in the presence of 10% fetal bovine serum, using pGL3-Luc and pEGFP-C1 as reporter plasmids. As compared with both PS-DNA nanoparticles and CaCO3-DNA nanoparticles, PS-CaCO3-DNA nanoparticles exhibited significantly enhanced gene delivery efficiency, which was higher than that of Lipofectamine 2000-DNA. Confocal microscopy observation showed that PS-CaCO3-DNA nanoparticles could efficiently deliver DNA to cell nuclei. These results indicated that the ternary PS-CaCO3-DNA nanoparticles prepared in this study have promising applications in gene delivery.

Dual-functionalized calcium carbonate based gene delivery system for efficient gene delivery

Dual-functionalized KALA/PS/CaCO₃/DNA nanoparticles containing a cell penetrating peptide (KALA) and protamine sulfate (PS) could effectively mediate gene transfection at a low DNA concentration.

Preparation of non-aggregated fluorescent nanodiamonds (FNDs) by non-covalent coating with a block copolymer and proteins for enhancement of intracellular uptake

Fluorescent nanodiamonds (FNDs) are very promising fluorophores for use in biosystems due to their high biocompatibility and photostability. To overcome their tendency to aggregate in physiological solutions, which severely limits the biological applications of FNDs, we developed a new non-covalent coating method using a block copolymer, PEG-b-P(DMAEMA-co-BMA), or proteins such as BSA and HSA. By simple mixing of the block copolymer with FNDs, the cationic DMAEMA and hydrophobic BMA moieties can strongly interact with the anionic and hydrophobic moieties on the FND surface, while the PEG block can form a shell to prevent the direct contact between FNDs. The polymer-coated FNDs, along with BSA- and HSA-coated FNDs, showed non-aggregation characteristics and maintained their size at the physiological salt concentration. The well-dispersed, polymer- or protein-coated FNDs in physiological solutions showed enhanced intracellular uptake, which was confirmed by CLSM. In addition, the biocompatibility of the coated FNDs was expressly supported by a cytotoxicity assay. Our simple non-covalent coating with the block copolymer, which can be easily modified by various chemical methods, projects a very promising outlook for future biomedical applications, especially in comparison with covalent coating or protein-based coating.