Exploring microRNAs in craniofacial regenerative medicine

microRNAs (miRs) have been reported over the decades as important regulators in bone development and bone regeneration. They play important roles in maintaining the stem cell signature as well as regulating stem cell fate decisions. Thus, delivering miRs and miR inhibitors to the defect site is a potential treatment towards craniofacial bone defects. However, there are challenges in translation of basic research to clinics, including the efficiency, specificity, and efficacy of miR manipulation methods and the safety of miR delivery systems. In this review, we will compare miR oligonucleotides, mimics and antagomirs as therapeutic reagents to treat disease and regenerate tissues. Newer technology will be discussed as well as the efficiency and efficacy of using these technologies to express or inhibit miRs in treating and repairing oral tissues. Delivery of these molecules using extracellular vesicles and nanoparticles can achieve different results and depending on their composition will elicit specific effects. We will highlight the specificity, toxicity, stability, and effectiveness of several miR systems in regenerative medicine.

A Polyplex in a Shell: The Effect of Poly(aspartic acid)-Mediated Calcium Carbonate Mineralization on Polyplexes Properties and Transfection Efficiency

Mineralization by exposure of organic templates to supersaturated solutions is used by many living organisms to generate specialized materials to perform structural or protective functions. Similarly, it was suggested that improved robustness acquired through mineralization under natural conditions could be an important factor for virus survival outside of a host for better transfection of cells. Here, inspired by this fact, we developed a nonviral tricomponent polyplex system for gene delivery capable of undergoing mineralization. First, we fabricated anionic polyplexes carrying pDNA by self-assembly with a lipid-modified cationic polymer and coating by poly(aspartic acid). Then, we submitted the polyplexes to a two-step mineralization reaction to precipitate CaCO₃ under various supersaturations. We carried out detailed morphological studies of the mineralized polyplexes and identified which parameters of the fabrication process were influential on transfection efficiency. We found that mineralization with CaCO₃ is efficient in promoting transfection efficiency as long as a certain Ca²⁺/CO₃^2- lower limit ratio is respected. However, calcium incubation can also be used to achieve similar effects at higher concentrations depending on polyplex composition, probably due to the formation of physical cross-links by calcium binding to poly(aspartic acid). We proposed that the improved robustness and transfection efficiency provided by means of mineralization can be used to expand the possible applications of polyplexes in gene therapy.

Mineralized vectors for gene therapy

There is an intense interest in developing materials for safe and effective delivery of polynucleotides using non-viral vectors. Mineralization of organic templates has long been used to produce complex materials with outstanding biocompatibility. However, a lack of control over mineral growth has limited the applicability of mineralized materials to a few in vitro applications. With better control over mineral growth and surface functionalization, mineralized vectors have advanced significantly in recent years. Here, we review the recent progress in chemical synthesis, physicochemical properties, and applications of mineralized materials in gene therapy, focusing on structure-function relationships. We contrast the classical understanding of the mineralization mechanism with recent ideas of mineralization. A brief introduction to gene delivery is summarized, followed by a detailed survey of current mineralized vectors. The vectors derived from calcium phosphate are articulated and compared to other minerals with unique features. Advanced mineral vectors derived from templated mineralization and specialty coatings are critically analyzed. Mineral systems beyond the co-precipitation are explored as more complex multicomponent systems. Finally, we conclude with a perspective on the future of mineralized vectors by carefully demarcating the boundaries of our knowledge and highlighting ambiguous areas in mineralized vectors. STATEMENT OF SIGNIFICANCE: Therapy by gene-based medicines is increasingly utilized to cure diseases that are not alleviated by conventional drug therapy. Gene medicines, however, rely on macromolecular nucleic acids that are too large and too hydrophilic for cellular uptake. Without tailored materials, they are not functional for therapy. One emerging class of nucleic acid delivery system is mineral-based materials. The fact that they can undergo controlled dissolution with minimal footprint in biological systems are making them attractive for clinical use, where safety is utmost importance. In this submission, we will review the emerging synthesis technology and the range of new generation minerals for use in gene medicines.

Synthesis and Characterization of Gefitinib and Paclitaxel Mono and Dual Drug-Loaded Blood Cockle Shells (Anadara granosa)-Derived Aragonite CaCO3 Nanoparticles

Calcium carbonate has slowly paved its way into the field of nanomaterial research due to its inherent properties: biocompatibility, pH-sensitivity, and slow biodegradability. In our efforts to synthesize calcium carbonate nanoparticles (CSCaCO₃NP) from blood cockle shells (Anadara granosa), we developed a simple method to synthesize CSCaCO₃NP, and loaded them with gefitinib (GEF) and paclitaxel (PTXL) to produce mono drug-loaded GEF-CSCaCO₃NP, PTXL-CSCaCO₃NP, and dual drug-loaded GEF-PTXL-CSCaCO₃NP without usage of toxic chemicals. Fourier-transform infrared spectroscopy (FTIR) results reveal that the drugs are bound to CSCaCO₃NP. Scanning electron microscopy studies reveal that the CSCaCO₃NP, GEF-CSCaCO₃NP, PTXL-CSCaCO₃NP, and GEF-PTXL-CSCaCO₃NP are almost spherical nanoparticles, with a diameter of 63.9 ± 22.3, 83.9 ± 28.2, 78.2 ± 26.4, and 87.2 ± 26.7 (nm), respectively. Dynamic light scattering (DLS) and N₂ adsorption-desorption experiments revealed that the synthesized nanoparticles are negatively charged and mesoporous, with surface areas ranging from ~8 to 10 (m²/g). Powder X-ray diffraction (PXRD) confirms that the synthesized nanoparticles are aragonite. The CSCaCO₃NP show excellent alkalinization property in plasma simulating conditions and greater solubility in a moderately acidic pH medium. The release of drugs from the nanoparticles showed zero order kinetics with a slow and sustained release. Therefore, the physico-chemical characteristics and in vitro findings suggest that the drug loaded CSCaCO₃NP represent a promising drug delivery system to deliver GEF and PTXL against breast cancer.

MicroRNA function in craniofacial bone formation, regeneration and repair

Bone formation in the craniofacial complex is regulated by cranial neural crest (CNC) and mesoderm-derived cells. Different elements of the developing skull, face, mandible, maxilla (jaws) and nasal bones are regulated by an array of transcription factors, signaling molecules and microRNAs (miRs). miRs are molecular modulators of these factors and act to restrict their expression in a temporal-spatial mechanism. miRs control the different genetic pathways that form the craniofacial complex. By understanding how miRs function in vivo during development they can be adapted to regenerate and repair craniofacial genetic anomalies as well as bone diseases and defects due to traumatic injuries. This review will highlight some of the new miR technologies and functions that form new bone or inhibit bone regeneration.

CaCO3 crystals as versatile carriers for controlled delivery of antimicrobials

CaCO₃ crystals have been known for a long time as naturally derived and simply fabricated nano(micro)-sized materials able to effectively host and release various molecules. This review summarises the use of CaCO₃ crystals as versatile carriers to host, protect and release antimicrobials, offering a strong tool to tackle antimicrobial resistance, a serious global health problem. The main methods for the synthesis of CaCO₃ crystals with different properties, as well as the approaches for the loading and release of antimicrobials are presented. Finally, prospects to utilize the crystals in order to improve the therapeutic outcome and combat antimicrobial resistance are highlighted. Ultimately, this review intends to provide an in-depth overview of the application of CaCO₃ crystals for the smart and controlled delivery of antimicrobial agents and aims at identifying the advantages and drawbacks as well as guiding future works, research directions and industrial applications.

Biodegradable calcium phosphate nanoparticles for cancer therapy

Calcium phosphate is the inorganic mineral of hard tissues such as bone and teeth. Due to their similarities to the natural bone, calcium phosphates are highly biocompatible and biodegradable materials that have found numerous applications in dental and orthopedic implants and bone tissue engineering. In the form of nanoparticles, calcium phosphate nanoparticles (CaP's) can also be used as effective delivery vehicles to transfer therapeutic agents such as nucleic acids, drugs, proteins and enzymes into tumor cells. In addition, facile preparation and functionalization of CaP's, together with their inherent properties such as pH-dependent solubility provide advantages in delivery and release of these bioactive agents using CaP's as nanocarriers. In this review, the challenges and achievements in the intracellular delivery of these agents to tumor cells are discussed. Also, the most important issues in the design and potential applications of CaP-based biominerals are addressed with more focus on their biodegradability in tumor microenvironment.

Synergism of cisplatin-oleanolic acid co-loaded calcium carbonate nanoparticles on hepatocellular carcinoma cells for enhanced apoptosis and reduced hepatotoxicity

Background: Cisplatin (CDDP), a widely used chemotherapeutic agent against hepatocellular carcinoma (HCC), faces severe resistance and hepatotoxicity problems which can be alleviated through combination therapy.

Purpose: The objective of this study was to develop a pH-dependent calcium carbonate nano-delivery system for the combination therapy of CDDP with oleanolic acid (OA).

Methods: A microemulsion method was employed to generate lipid coated cisplatin/oleanolic acid calcium carbonate nanoparticles (CDDP/OA-LCC NPs), and the loading concentration of CDDP and OA was measured by atomic absorption spectroscopy and HPLC respectively.Transmission electron microscopy (TEM) was used to examine the nanoparticles morphology while its pH dependent release characteristics were investigated through in vitro release study. Cellular uptake was examined through a fluorescence microscopy. Apoptotic assays and western blot analysis were conducted to explore the synergistic apoptotic effect of OA on CDDP against HCC cells. The hepatoprotective of OA for CDDP was evaluated through H&E staining.

Results: TEM analysis revealed nanoparticles spherical shape with an average particle size of 206±15 nm, and the overall entrapment efficiency was 63.70%±3.9%. In vitro drug release study confirmed the pH-dependent property of the formulation, with the maximum CDDP release of 70%±4.6% at pH 5.5, in contrast to 28%±4.1% CDDP release at pH 7.4. Annexin V-FITC/PI assay and cell cycle analysis confirmed that CDDP and OA synergistically promoted greater HepG2 cells apoptosis for the CDDP/OA-LCC NPs as compared to their individual free drug solutions and NPs-treated groups. Western blot analysis also proved that CDDP/OA-LCC NPs induced the apoptosis by enhancing the proapoptotic protein expressions through downregulating P13K/AKT/mTOR pathway and upregulating p53 proapoptotic pathway. OA helped CDDP to overcome the resistance by downregulating the expression of proteins like XIAP, Bcl-2 via NF-κB pathway. OA also significantly alleviated CDDP-induced hepatotoxicity as evident from the decreased alanine transaminase, aspartate transaminase levels and histochemical evaluation. The possible mechanism may be related to the Nrf-2 induction via its antioxidant mechanism to maintain the redox balance and reduction in CYP2E1 activity which can lead to ROS-mediated oxidative stress.

Conclusion: These results suggest that CDDP/OA-LCC NPs have promising applications for co-delivering CDDP and OA to synergize their anti-tumor activity against HCC and to utilize OA’s protective effect against CDDP-induced hepatotoxicity.

Calcium-based biomaterials for diagnosis, treatment, and theranostics

Calcium-based biomaterials with good biosafety and bio-absorbability are promising for biomedical applications such as diagnosis, treatment, and theranostics.

Photo-derived transformation from modified chitosan@calcium carbonate nanohybrids to nanosponges

Zwitterionic chitosan (ZC)@calcium carbonate (CC) nanoparticles were conveniently obtained and transformed to biocompatible nanosponges by continuous gas-phase photo-derived transformation in a single-pass configuration, and their potential use for biomedical applications was investigated. The mean diameter of the ZC@CC sponges was ~166 nm (~72 nm for CC and, ~171 nm for ZC), and the sponges had a mesoporous structure (i.e., an average pore diameter of ~13 nm). Measurements of the sponge cytotoxicity were performed and only a slight decrease was observed (>78% in cell viability) when compared with pure ZC (>80%). The ZC@CC sponges had a similar transfection ability to lipofectamine (~2.7 × 10⁹ RLU mg⁻¹ protein) at a 50:1 ratio of sponge:DNA weight. Because of a porous structure, the sponges showed remarkably higher transfection efficiencies than pure ZC.

Using HEK293T Expression System to Study Photoactive Plant Cryptochromes

Cryptochromes are photolyase-like blue light receptors that are conserved in plants and animals. Although the light-dependent catalytic mechanism of photolyase is well studied, the photochemical mechanism of cryptochromes remains largely unknown. Lack of an appropriate protein expression system to obtain photochemically active cryptochrome holoproteins is a technical obstacle for the study of plant cryptochromes. We report here an easy-to-use method to express and study Arabidopsis cryptochrome in HEK293T cells. Our results indicate that Arabidopsis cryptochromes expressed in HEK293T are photochemically active. We envision a broad use of this method in the functional investigation of plant proteins, especially in the large-scale analyses of photochemical activities of cryptochromes such as blue light-dependent protein-protein interactions.

Calcium carbonate nanoparticles as cancer drug delivery system

INTRODUCTION

Calcium carbonate (CaCO3) has broad biomedical utilizations owing to its availability, low cost, safety, biocompatibility, pH-sensitivity and slow biodegradability. Recently, there has been widespread interest in their application as drug delivery systems for different groups of drugs. Among them, CaCO3 nanoparticles have exhibited promising potential as drug carriers targeting cancer tissues and cells. The pH-dependent properties, alongside the potential to be functionalized with targeting agents give them the unique property that can be used in targeted delivery systems for anticancer drugs. Also, due to the slow degradation of CaCO3 matrices, these nanoparticles can be used as sustained release systems to retain drugs in cancer tissues for longer times after administration.

AREAS COVERED

Development of drug delivery carriers using CaCO3 nanoparticles has been reviewed. The current state of CaCO3 nanoparticles as cancer drug delivery systems with focus on their special properties like pH-sensitivity and biodegradability has also been evaluated.

EXPERT OPINION

According to our review, CaCO3 nanoparticles, owing to their special characteristics, will have a potential role in safe and efficient cancer treatment in future.

Application of Box-Behnken design to prepare gentamicin-loaded calcium carbonate nanoparticles

The aim of this research was to prepare and optimize calcium carbonate (CaCO3) nanoparticles as carriers for gentamicin sulfate. A chemical precipitation method was used to prepare the gentamicin sulfate-loaded CaCO3 nanoparticles. A 3-factor, 3-level Box-Behnken design was used for the optimization procedure, with the molar ratio of CaCl2: Na2CO3 (X1), the concentration of drug (X2), and the speed of homogenization (X3) as the independent variables. The particle size and entrapment efficiency were considered as response variables. Mathematical equations and response surface plots were used, along with the counter plots, to relate the dependent and independent variables. The results indicated that the speed of homogenization was the main variable contributing to particle size and entrapment efficiency. The combined effect of all three independent variables was also evaluated. Using the response optimization design, the optimized Xl-X3 levels were predicted. An optimized formulation was then prepared according to these levels, resulting in a particle size of 80.23 nm and an entrapment efficiency of 30.80%. It was concluded that the chemical precipitation technique, together with the Box-Behnken experimental design methodology, could be successfully used to optimize the formulation of drug-incorporated calcium carbonate nanoparticles.

Sandwich-type Au-PEI/DNA/PEI-Dexa nanocomplex for nucleus-targeted gene delivery in vitro and in vivo

Many synthetic Au-based cationic nanoparticles (AuNPs) for nonviral gene delivery show high efficiency in vitro, but their excessive charge density, harsh reducing conditions, and nontarget delivery prevent their application in vivo. Herein, we constructed a sandwich-type layered polyethylenimine (PEI)-coated gold nanocomposite outerlaid with a nucleus-targeted Dexamethasone (Dexa), namely, Au-PEI/DNA/PEI-Dexa nanocomplex, for DNA delivery system using a low molecular weight PEI as a mild reducing agent. The nucleus-targeting Au-PEI/DNA/PEI-Dexa nanocomplex with low positive charge and low cytotoxicity condensed DNA and protected from enzymatic degradation. In vitro transfection studies demonstrated that Au-PEI/DNA/PEI-Dexa nanocomplex exhibited much more efficient nucleus transfection than Au-PEI/DNA/PEI without nucleus-targeted residues and commercially available PEI 25 kDa due to the Dexa targeting of the nucleus. Furthermore, the nanocomplex markedly transfected pTRAIL (TRAIL = tumor-necrosis-factor-related apoptosis-inducing ligand) to tumors in vivo and subsequently inhibited the tumor growth with minimal side effects. These findings suggest that nucleus-targeting Au-PEI/DNA/PEI-Dexa ternary complexes have promising potential in gene delivery.

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.

Alginate/CaCO3 hybrid nanoparticles for efficient codelivery of antitumor gene and drug

In this study, a facile strategy for efficient codelivery of gene and drug was developed. Using a coprecipitation method, doxorubicin hydrochloride (DOX), an antitumor drug, and p53 expression plasmid were encapsulated in alginate/CaCO(3)/DNA/DOX nanoparticles with high encapsulation efficiency. The in vitro cell inhibition effect of the alginate/CaCO(3)/DNA/DOX nanoparticles was evaluated by MTT assay in HeLa cells. The alginate/CaCO(3)/DNA/DOX nanoparticles exhibited a high cell inhibition rate about 80%, indicating that the alginate/CaCO(3)/DNA/DOX nanoparticles could effectively mediate gene transfection and deliver the drug to the cells. Compared with the codelivery of gene and drug, the treatments by alginate/CaCO(3)/DOX nanoparticles and alginate/CaCO(3)/DNA nanoparticles separately led to much lower cell inhibition rates. Compared with the CaCO(3)/DNA/DOX nanoparticles without alginate modification, the alginate/CaCO(3)/DNA/DOX nanoparticles with a decreased particle size exhibited enhanced delivery efficiency. The alginate/CaCO(3)/DNA/DOX nanoparticles have promising applications in cancer treatments.

Efficient in vivo gene transfer by intraperitoneal injection of plasmid DNA and calcium carbonate microflowers in mice

Gene transfer to intraperitoneal organs is thought to be a promising approach to treat such conditions as peritoneal fibrosis and peritoneal dissemination of cancers. We previously discovered that simple instillation of naked plasmid DNA (pDNA) onto intraperitoneal organs such as the liver and stomach could effectively transfer foreign genes in mice. In this study, we developed a novel nonviral method to enhance transfection efficiency of naked pDNA to intraperitoneal organs using a calcium carbonate suspension containing pDNA. Using commercially available calcium carbonate, we successfully transfected pDNA to the stomach. Handling of commercially available calcium carbonate, however, was troublesome owing to rapid precipitation and caking. To obtain slowly settling particles of calcium carbonate, we tried to synthesize novel versions of such particles and succeeded in creating flower-shaped particles, named calcium carbonate microflowers. Sedimentation of calcium carbonate microflowers was sufficiently slow for in vivo experiments. Moreover, the transfection efficiency of the suspension of calcium carbonate microflowers to the stomach was more effective than that of commercially available calcium carbonate, especially at low concentrations. Intraperitoneal injection of the suspension of calcium carbonate microflowers containing pDNA greatly enhanced naked pDNA transfer to whole intraperitoneal organs in mice. Furthermore, lactate dehydrogenase activities in intraperitoneal fluid and plasma were not raised by the suspension of calcium carbonate microflowers.

Calcium carbonate microparticles used as a gene vector for delivering p53 gene into cancer cells

Calcium carbonate (CaCO(3) ) microparticles were for the first time used for efficient delivery of p53 gene to transfect human cancer cells HeLa. CaCO(3) microparticles (2-4 μm) absorbed pEGFP-C1-p53 (expressing GFP-P53 fusion protein) to transfect HeLa cells. Flow cytometer (FCM) was used to evaluate the gene transfection efficiency in HeLa cells, which were stably transduced with a green fluorescent protein gene. In this study, CaCO(3) delivering pEGFP-C1-p53 could transfect about 5% of the tumor cells in culture. However, the efficiency of tumor cell apoptosis was surprisingly up to 80%. Meanwhile, the results of MTT assay and crystal violet staining showed that the CaCO(3) microparticles had low cytotoxicity. These findings showed that CaCO(3) microparticles were perspective to be used as new vectors for gene therapy.