Gelatin-based delivery systems for cancer gene therapy

Gelatin-Zinc Carrier as a New Method of Targeted and Controlled Release of Risedronate

The essence of drug delivery is to use an appropriate carrier that delivers the active substance to the appropriate pathogenic site at a specific time. This study aims to develop a novel drug carrier characterized by the controlled and targeted release of risedronate (RSD). The search for new routes to deliver RSD is important because oral delivery has many disadvantages. The carrier proposed in this work is composed of gelatin, polyphosphates, and zinc. The zinc contained in the carrier is responsible for coordinating the drug. The resulting material releases RSD in a controlled manner. The rate of delivery of the substance to the body depends on the pH of the environment. This study investigated the delivery of RSD in a neutral environment, where the process exhibited a prolonged and consistent release rate. This process has also been studied in an acidic environment, which accelerates the release of the drug. Mixed-environment studies were also conducted. Initially, the drug was released in a neutral environment, and then the conditions rapidly changed to acidic. In this case, the carrier demonstrated high stability and controlled release, adapting the rate of drug release to the prevailing environmental conditions. The presented results indicate the great potential of the new gelatin-based carrier in the delivery of risedronate.

Current research status and development prospects of embolic microspheres containing biological macromolecules and others

Transcatheter arterial embolization (TACE) has been used in the treatment of malignant tumors, sudden hemorrhage, uterine fibroids, and other diseases, and with advances in imaging techniques and devices, materials science, and drug release technology, more and more embolic agents that are drug-carrying, self-imaging, or have multiple functions are being developed. Microspheres provide safer and more effective therapeutic results as embolic agents, with their unique spherical appearance and good embolic properties. Embolic microspheres are the key to arterial embolization, blocking blood flow and nutrient supply to the tumor target. This review summarizes some of the currently published embolic microspheres, classifies embolic microspheres according to matrix, and summarizes the characteristics of the microsphere materials, the current status of research, directions, and the value of existing and potential applications. It provides a direction to promote the development of embolic microspheres towards multifunctionalization, and provides a reference to promote the research and application of embolic microspheres in the treatment of tumors.

Sustained Release Studies of Metformin Hydrochloride Drug Using Conducting Polymer/Gelatin-Based Composite Hydrogels

The present work highlights the synthesis and characterization of conducting polymer (CP)-based composite hydrogels with gelatin (GL-B) for their application as drug delivery vehicles. The spectral, morphological, and rheological properties of the synthesized hydrogels were explored, and morphological studies confirmed formation of an intense interpenetrating network. Rheological measurements showed variation in the flow behavior with the type of conducting polymer. The hydrogels showed a slow drug release rate of about 10 h due to the presence of the conducting polymer. The release kinetics were fitted in various mathematical models and were best fit in first order for PNA-, POPD-, and PANI-based GL-B hydrogels, and the PVDF/GL-B hydrogel was best fit in the zero-order models. The drug release was found to follow the order: POPD/GL-B > PANI/GL-B > PVDF/GL-B.

Research progress related to thermosensitive hydrogel dressings in wound healing: a review

Wound healing is a dynamic and complex process in which the microenvironment at the wound site plays an important role. As a common material for wound healing, dressings accelerate wound healing and prevent external wound infections. Hydrogels have become a hot topic in wound-dressing research because of their high water content, good biocompatibility, and adjustable physical and chemical properties. Intelligent hydrogel dressings have attracted considerable attention because of their excellent environmental responsiveness. As smart polymer hydrogels, thermosensitive hydrogels can respond to small temperature changes in the environment, and their special properties make them superior to other hydrogels. This review mainly focuses on the research progress in thermosensitive intelligent hydrogel dressings for wound healing. Polymers suitable for hydrogel formation and the appropriate molecular design of the hydrogel network to achieve thermosensitive hydrogel properties are discussed, followed by the application of thermosensitive hydrogels as wound dressings. We also discuss the future perspectives of thermosensitive hydrogels as wound dressings and provide systematic theoretical support for wound healing.

Gelatin as a bioactive nanodelivery system for functional food applications

Gelatin has long been used as an encapsulant agent in the pharmaceutical and biomedical industries because of its low cost, wide availability, biocompatibility, and degradability. However, the exploitation of gelatin for nanodelivery application is not fully achieved in the functional food filed. In this review article, we highlight the latest work being performed for gelatin-based nanocarriers, including polyelectrolyte complexes, nanoemulsions, nanoliposomes, nanogels, and nanofibers. Specifically, we discuss the applications and challenges of these nanocarriers for stabilization and controlled release of bioactive compounds. To achieve better efficacy, gelatin is frequently used in combination with other biomaterials such as polysaccharides. The fabrication and synergistic effects of the newly developed gelatin composite nanocarriers are also present.

Alginates Combined with Natural Polymers as Valuable Drug Delivery Platforms

Alginates (ALG) have been used in biomedical and pharmaceutical technologies for decades. ALG are natural polymers occurring in brown algae and feature multiple advantages, including biocompatibility, low toxicity and mucoadhesiveness. Moreover, ALG demonstrate biological activities per se, including anti-hyperlipidemic, antimicrobial, anti-reflux, immunomodulatory or anti-inflammatory activities. ALG are characterized by gelling ability, one of the most frequently utilized properties in the drug form design. ALG have numerous applications in pharmaceutical technology that include micro- and nanoparticles, tablets, mucoadhesive dosage forms, wound dressings and films. However, there are some shortcomings, which impede the development of modified-release dosage forms or formulations with adequate mechanical strength based on pure ALG. Other natural polymers combined with ALG create great potential as drug carriers, improving limitations of ALG matrices. Therefore, in this paper, ALG blends with pectins, chitosan, gelatin, and carrageenans were critically reviewed.

Nanostructured particles assembled from natural building blocks for advanced therapies

Advanced treatments based on immune system manipulation, gene transcription and regulation, specific organ and cell targeting, and/or photon energy conversion have emerged as promising therapeutic strategies against a range of challenging diseases. Naturally derived macromolecules (e.g., proteins, lipids, polysaccharides, and polyphenols) have increasingly found use as fundamental building blocks for nanostructured particles as their advantageous properties, including biocompatibility, biodegradability, inherent bioactivity, and diverse chemical properties make them suitable for advanced therapeutic applications. This review provides a timely and comprehensive summary of the use of a broad range of natural building blocks in the rapidly developing field of advanced therapeutics with insights specific to nanostructured particles. We focus on an up-to-date overview of the assembly of nanostructured particles using natural building blocks and summarize their key scientific and preclinical milestones for advanced therapies, including adoptive cell therapy, immunotherapy, gene therapy, active targeted drug delivery, photoacoustic therapy and imaging, photothermal therapy, and combinational therapy. A cross-comparison of the advantages and disadvantages of different natural building blocks are highlighted to elucidate the key design principles for such bio-derived nanoparticles toward improving their performance and adoption. Current challenges and future research directions are also discussed, which will accelerate our understanding of designing, engineering, and applying nanostructured particles for advanced therapies.

Chitosan Nanoparticles in Atherosclerosis-Development to Preclinical Testing

Chitosan is a natural biopolymer that is present in an abundant supply in sources such as crustacean shells, mushrooms, and insect exoskeletons. It can be used to make a variety of types of drug formulations and is generally safe to use in vivo; plus, it has inherent cholesterol-reducing properties. While an abundance of papers has tested this biopolymer in nanoparticles in cancer and diabetes research, there is a lag of usage, and hence the paucity of information, in the area of cardiovascular research, specifically in atherosclerosis, the topic of this review. This review highlights some of the deficiencies in this niche area of research, examines the range of chitosan nanoparticles that have been researched to date, and proposes several ways forward to advance this field. Nanoparticles used for both diagnostic and therapeutic purposes are reviewed, with a discussion on how these nanoparticles could be better researched in future and what lays ahead as the field potentially moves towards clinical trials in future.

Dendronized Gelatins Showing Both LCST and UCST-type Thermoresponsive Behavior

Modification of natural polymers with stimuli-responsive synthetic moieties witnesses convergences of superior properties from natural polymers and stimuli-responsiveness to generate new intelligent materials. This was usally performed through synthetic polymers...

Bone tissue engineering gelatin-hydroxyapatite/graphene oxide scaffolds with the ability to release vitamin D: fabrication, characterization, and in vitro study

Developing smart scaffolds with drug release capability is one of the main approaches to bone tissue engineering. The current study involves the fabrication of novel gelatin (G)-hydroxyapatite (HA)-/vitamin D (VD)-loaded graphene oxide (GO) scaffolds with different concentrations through solvent-casting method. Characterizations confirmed the successful synthesis of HA and GO, and VD was loaded in GO with 36.87 ± 4.87% encapsulation efficiency. Physicochemical characterizations showed that the scaffold containing 1% VD-loaded GO had the best mechanical properties and its porosity percentage and density was in the range of natural spongy bone. All scaffolds were degraded after 1-month, subjecting to phosphate buffer saline. The release profile of VD did not match any mathematical kinetics model, porosities and the degradation rate of the scaffolds were dominant controlling factors of release behavior. Studies on the bioactivity of scaffolds immersed in simulated body fluid indicated that VD and HA could encourage the formation of secondary apatite crystals in vitro. Buccal fat pad-derived stem cells (BFPSCs) were seeded on the scaffolds, MTT assay, alkaline phosphatase activity as an indicator of osteoconductivity, and cell adhesion were conducted in order to evaluate in vitro biological responses. All scaffolds highly supported cell adhesion, MTT assay indicated better cell viability in 0.5% VD-loaded GO containing scaffold, and the scaffold enriched with 2% VD-loaded GO performed the most ALP activity. The results demonstrated the potential of these scaffolds to induce bone regeneration. Developing smart scaffolds with drug release capability is one of the main approaches to bone tissue engineering. The current study involves the fabrication of novel gelatin (G)-hydroxyapatite (HA)-/vitamin D (VD)-loaded graphene oxide (GO) scaffolds with different concentrations through solvent-casting method. Characterizations confirmed the successful synthesis of HA and GO, and VD was loaded in GO with 36.87 ± 4.87% encapsulation efficiency. Physicochemical characterizations showed that the scaffold containing 1% VD-loaded GO had the best mechanical properties and its porosity percentage and density was in the range of natural spongy bone. All scaffolds were degraded after 1-month, subjecting to phosphate buffer saline. The release profile of VD did not match any mathematical kinetics model, porosities and the degradation rate of the scaffolds were dominant controlling factors of release behavior. Studies on the bioactivity of scaffolds immersed in simulated body fluid indicated that VD and HA could encourage the formation of secondary apatite crystals in vitro. Buccal fat pad-derived stem cells (BFPSCs) were seeded on the scaffolds, MTT assay, alkaline phosphatase activity as an indicator of osteoconductivity, and cell adhesion were conducted in order to evaluate in vitro biological responses. All scaffolds highly supported cell adhesion, MTT assay indicated better cell viability in 0.5% VD-loaded GO containing scaffold, and the scaffold enriched with 2% VD-loaded GO performed the most ALP activity. The results demonstrated the potential of these scaffolds to induce bone regeneration.

Otoliths-composed gelatin/sodium alginate scaffolds for bone regeneration

Evidence that otoliths, mineral-rich limestone concrescences present in the inner ear of bone fishes, can accelerate bone formation in vivo has been previously reported. The goal of this work was the development, characterization, and evaluation of the cytocompatibility of otoliths-incorporated sodium alginate and gelatin scaffolds. Cynoscion acoupa-derived otoliths were characterized by X-ray fluorescence spectrometry (FRX), particle size, free lime, and weight loss by calcination. Furthermore, otoliths were incorporated into sodium alginate (ALG/OTL-s) or gelatin (GEL/OTL-s) scaffolds, previously developed by freeze-drying. Then, the scaffolds were characterized by thermogravimetric analysis (TGA/DTG), differential scanning calorimetry (DSC), infrared spectroscopy with Fourier transform (FTIR), swelling tests, and scanning electron microscopy (SEM). Cytotoxicity assays were run against J774.G8 macrophages and MC3T3-E1 osteoblasts. Data obtained from TGA/DTG, DSC, and FTIR analyses confirmed the interaction between otoliths and the polymeric scaffolds. SEM showed the homogeneous porous 3D structure rich in otolith micro-fragments in both scaffolds. Swelling of the GEL/OTL-s (63.54 ± 3.0%) was greater than of ALG/OTL-s (13.36 ± 9.9%) (p < 0.001). The viability of J774.G8 macrophages treated with both scaffolds was statistically similar to the group treated with DMEM only (p > 0.05) and significantly higher than that treated with Triton-X (p < 0.01) at 72 h. Both scaffolds showed approximately 100% growth of MC3T3-E1 osteoblasts by 24 h, similarly to control (p > 0.05). However, by 48 h, only ALG/OTL-s showed growth similar to control (p > 0.05), whereas GEL/OTL showed a significantly lower growth index (p < 0.05). In conclusion, the physicochemical profiles suggest proper interaction between the otoliths and the two developed polymeric 3D scaffolds. Moreover, both materials showed cytocompatibility with J774.G8 macrophages but the growth of MC3T3-E1 osteoblasts was higher when exposed to ALG/OTL-s. These data suggest that sodium alginate/otoliths scaffolds are potential biomaterials to be used in bone regeneration applications. Graphical abstract.

Natural Hydrogels Applied in Photodynamic Therapy

Natural hydrogels are three-dimensional (3D) water-retaining materials with a skeleton consisting of natural polymers, their derivatives or mixtures. Natural hydrogels can provide sustained or controlled drug release and possess some unique properties of natural polymers, such as biodegradability, biocompatibility and some additional functions, such as CD44 targeting of hyaluronic acid. Natural hydrogels can be used with photosensitizers (PSs) in photodynamic therapy (PDT) to increase the range of applications. In the current review, the pertinent design variables are discussed along with a description of the categories of natural hydrogels available for PDT.

Gelatin Promotes Cell Retention Within Decellularized Heart Extracellular Matrix Vasculature and Parenchyma

Introduction

Recellularization of organ decellularized extracellular matrix (dECM) offers a potential solution for organ shortage in allograft transplantation. Cell retention rates have ranged from 10 to 54% in varying approaches for reseeding cells in whole organ dECM scaffolds. We aimed to improve recellularization by using soluble gelatin as a cell carrier to deliver endothelial cells to the coronary vasculature and cardiomyocytes to the parenchyma in a whole decellularized rat heart.

Methods

Rat aortic endothelial cells (RAECs) were perfused over decellularized porcine aorta in low (1%) and high (5%) concentrations of gelatin to assess attachment to a vascular dECM model. After establishing cell viability and proliferation in 1% gelatin, we used 1% gelatin as a carrier to deliver RAECs and neonatal rat cardiomyocytes (NRCMs) to decellularized adult rat hearts. Immediate cell retention in the matrix was quantified, and recellularized hearts were evaluated for visible contractions up to 35 days after recellularization.

Results

We demonstrated that gelatin increased RAEC attachment to decellularized porcine aorta; blocking integrin receptors reversed this effect. In the whole rat heart gelatin (1%) increased retention of both RAECs and NRCMs respectively, compared with the control group (no gelatin). Gelatin was associated with visible contractions of NRCMs within hearts (87% with gelatin vs. 13% control).

Conclusions

Gelatin was an effective cell carrier for increasing cell retention and contraction in dECM. The gelatin-cell-ECM interactions likely mediated by integrin.

Natural polypeptides-based electrically conductive biomaterials for tissue engineering

Fabrication of an appropriate scaffold is the key fundamental step required for a successful tissue engineering (TE). The artificial scaffold as extracellular matrix in TE has noticeable role in the fate of cells in terms of their attachment, proliferation, differentiation, orientation and movement. In addition, chemical and electrical stimulations affect various behaviors of cells such as polarity and functionality. Therefore, the fabrication approach and materials used for the preparation of scaffold should be more considered. Various synthetic and natural polymers have been used extensively for the preparation of scaffolds. The electrically conductive polymers (ECPs), moreover, have been used in combination with other polymers to apply electric fields (EF) during TE. In this context, composites of natural polypeptides and ECPs can be taken into account as context for the preparation of suitable scaffolds with superior biological and physicochemical features. In this review, we overviewed the simultaneous usage of natural polypeptides and ECPs for the fabrication of scaffolds in TE.

Predicting degradation rate of genipin cross-linked gelatin scaffolds with machine learning

Genipin can improve weak mechanical properties and control high degradation rate of gelatin, as a cross-linker of gelatin which is widely used in tissue engineering. In this study, genipin cross-linked gelatin biodegradable porous scaffolds with different weight percentages of gelatin and genipin were prepared for tissue regeneration and measurement of their various properties including morphological characteristics, mechanical properties, swelling, degree of crosslinking and degradation rate. Results indicated that the sample containing the highest amount of gelatin and genipin had the highest degree of crosslinking and increasing the percentage of genipin from 0.125% to 0.5% enhances ultimate tensile strength (UTS) up to 113% and 92%, for samples with 2.5% and 10% gelatin, respectively. For these samples, increasing the percentage of genipin, reduce their degradation rate significantly with an average value of 124%. Furthermore, experimental data are used to develop a machine learning model, which compares artificial neural networks (ANN) and kernel ridge regression (KRR) to predict degradation rate of genipin-cross-linked gelatin scaffolds as a property of interest. The predicted degradation rate demonstrates that the ANN, with mean squared error (MSE) of 2.68%, outperforms the KRR with MSE = 4.78% in terms of accuracy. These results suggest that machine learning models offer an excellent prediction accuracy to estimate the degradation rate which will significantly help reducing experimental costs needed to carry out scaffold design.

Impact of Gelatin Supplemented with Gum Arabic, Tween 20, and β-Cyclodextrin on the Microencapsulation of Turkish Oregano Extract

Microencapsulation protects core materials from deteriorating due to environmental conditions, such as moisture or oxidation, and improves the bioavailability of active compounds, allowing one to make solid formulations from oils and increase their solubility. Wall and core material properties determine the microencapsulation efficiency and the best results are achieved when a wall material mixture is used to prepare the microcapsules. In this work, we optimized the wall material composition (gelatin supplemented with gum Arabic, Tween 20, and β-cyclodextrin) of Turkish oregano microcapsules prepared by spray-drying technology to increase the product yield, the encapsulation efficiency, and to achieve narrower particle size distribution. When the wall material solution contained 10 g of gelatin, 7.5 g of gum Arabic, 1.99 g of Tween 20, 1.98 g of β-cyclodextrin, and 20 g of ethanolic oregano extract, the encapsulation efficiency of oregano's active compounds, rosmarinic acid and carvacrol, were 96.7% and 99.8%, respectively, and the product yield was 85.63%. The physicochemical properties, microscopic morphology, and in vitro release of the prepared microcapsules were characterized in the study. The use of gelatin as the main coating material, in supplementation with gum Arabic, Tween 20, and β-cyclodextrin, not only improved the encapsulation efficiency, but also increased the in vitro release of both main active compounds of Turkish oregano extract-rosmarinic acid and carvacrol.

Targeting of high mobility group A2 by small interfering RNA-loaded nanoliposome-induced apoptosis and migration inhibition in gastrointestinal cancer cells

BACKGROUND

Considering the complex nature of gastrointestinal cancer, different methods including surgery, radiotherapy, and chemotherapy are considered for the treatment. Novel strategies including silencing of oncogenes using safe delivery systems could be considered as a novel approach in colorectal cancer treatment. The aim of this study was to investigate the silencing effect of high mobility group A2 (HMGA2) small interfering RNA (siRNA)-loaded nanoliposomes on gastrointestinal cancers.

METHODS

The siRNA-lipoplexes were prepared using dioleoyl trimethylammonium propane (DOTAP)/cholesterol (Chol)/1, 2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) through the freeze-drying of a monophase solution method. The size, polydispersity index (PDI), and zeta-potential of nanoliposomes were determined using Zetasizer analyzer. The morphology of the nanoliposomes was determined by transmission electron microscopy (TEM). The agarose gel-retardation assay was carried out to confirm the loading of siRNAs into liposome. The silencing of the HMGA2 in cancer cells was evaluated by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The effect of liposomes on cell cytotoxicity was studied by MTT assay. The inhibitory effect of siRNA-loaded liposomes was evaluated by a wound-healing assay. The apoptosis induction was investigated via the annexin V/propidium iodide assay.

RESULTS

The size, PDI, and zeta-potential of the prepared liposomes were found to be 350 nm, 0.67, and 86.3 mV, respectively. They were spherical in shape and could efficiently associate with siRNA. The results of gene silencing showed that the optimum condition of HMGA2 silencing was 80 pmol HMGA2 and 24 hours after treatment in each cancer cell lines. MTT assays indicated that silencing of HMGA2 in optimal condition could reduce the viability of the cancer cells more than 60% in the three cell lines. The result of the apoptosis assay showed more than 50% of the cell deaths related to the apoptosis in all three cell lines. The gene expression evaluation confirmed that apoptosis was induced via the intrinsic pathway inducing both caspase-3 and -9 expressions. Also, the reduction in Bcl2 expression confirmed the activation apoptosis pathway in the treated cancer cells. The wound-healing assay showed the suppression of cancer cell migration after treatment with the prepared nanoliposomes.

CONCLUSION

The results of this study showed the HMGA2 siRNA-loaded nanoliposomes could be effective in the treatment of gastrointestinal cancers.

Bio-Inspired Protein-Based Nanoformulations for Cancer Theranostics

Over the past decade, more interests have been aroused in engineering protein-based nanoformulations for cancer treatment. This excitement originates from the success of FDA approved Abraxane (Albumin-based paclitaxel nanoparticles) in 2005. The new generation of biocompatible endogenous protein-based nanoformulations is currently constructed through delivering cancer therapeutic and diagnostic agents simultaneously, as named potential theranostics. Protein nanoformulations are commonly incorporated with dyes, contrast agents, drug payloads or inorganic nanoclusters, serving as imaging-guided combinatorial cancer therapeutics. Employing the nature identity of proteins, the theranostics, escape the clearance by reticuloendothelial cells and have a long blood circulation time. The nanoscale sizet allows them to be penetrated deeply into tumor tissues. In addition, stimuli release and targeted molecules are incorporated to improve the delivery efficiency. The ongoing advancement of protein-based nanoformulations for cancer theranostics in recent 5 years is reviewed in this paper. Fine-designed nanoformulations based on albumin, ferritin, gelatin, and transferrin are highlighted from the literature. Finally, the current challenges are identified in translating protein-based nanoformulations from laboratory to clinical trials.

In Vivo Bio-distribution and Efficient Tumor Targeting of Gelatin/Silica Nanoparticles for Gene Delivery

The non-viral gene delivery system is an attractive alternative to cancer therapy. The clinical success of non-viral gene delivery is hampered by transfection efficiency and tumor targeting, which can be individually overcome by addition of functional modules such as cell penetration or targeting. Here, we first engineered the multifunctional gelatin/silica (GS) nanovectors with separately controllable modules, including tumor-targeting aptamer AGRO100, membrane-destabilizing peptide HA2, and polyethylene glycol (PEG), and then studied their bio-distribution and in vivo transfection efficiencies by contrast resonance imaging (CRI). The results suggest that the sizes and zeta potentials of multifunctional gelatin/silica nanovectors were 203-217 nm and 2-8 mV, respectively. Functional GS-PEG nanoparticles mainly accumulated in the liver and tumor, with the lowest uptake by the heart and brain. Moreover, the synergistic effects of tumor-targeting aptamer AGRO100 and fusogenic peptide HA2 promoted the efficient cellular internalization in the tumor site. More importantly, the combined use of AGRO100 and PEG enhanced tumor gene expression specificity and effectively reduced toxicity in reticuloendothelial system (RES) organs after intravenous injection. Additionally, low accumulation of GS-PEG was observed in the heart tissues with high gene expression levels, which could provide opportunities for non-invasive gene therapy.

Effect of gelatin sponge with colloid silver on bone healing in infected cranial defects

Oral infectious diseases may lead to bone loss, which makes it difficult to achieve satisfactory restoration. The rise of multidrug resistant bacteria has put forward severe challenges to the use of antibiotics. Silver (Ag) has long been known as a strong antibacterial agent. In clinic, gelatin sponge with colloid silver is used to reduce tooth extraction complication. To investigate how this material affect infected bone defects, methicillin-resistant Staphylococcus aureus (MRSA) infected 3-mm-diameter cranial defects were created in adult female Sprague-Dawley rats. One week after infection, the defects were debrided of all nonviable tissue and then implanted with gelatin sponge with colloid silver (gelatin/Ag group) or gelatin alone (gelatin group). At 2 and 3days after debridement, significantly lower mRNA expression levels of IL-6 and TNF-α and lower plate colony count value were detected in gelatin/Ag group than control. Micro-CT analysis showed a significant increase of newly formed bone volume fraction (BV/TV) in gelatin/Ag treated defects. The HE stained cranium sections also showed a faster rate of defect closure in gelatin/Ag group than control. These findings demonstrated that gelatin sponge with colloid silver can effectively reduce the infection caused by MRSA in cranial defects and accelerate bone healing process.

Functional nucleic acid-based hydrogels for bioanalytical and biomedical applications

Hydrogels are crosslinked hydrophilic polymers that can absorb a large amount of water. By their hydrophilic, biocompatible and highly tunable nature, hydrogels can be tailored for applications in bioanalysis and biomedicine. Of particular interest are DNA-based hydrogels owing to the unique features of nucleic acids. Since the discovery of the DNA double helical structure, interest in DNA has expanded beyond its genetic role to applications in nanotechnology and materials science. In particular, DNA-based hydrogels present such remarkable features as stability, flexibility, precise programmability, stimuli-responsive DNA conformations, facile synthesis and modification. Moreover, functional nucleic acids (FNAs) have allowed the construction of hydrogels based on aptamers, DNAzymes, i-motif nanostructures, siRNAs and CpG oligodeoxynucleotides to provide additional molecular recognition, catalytic activities and therapeutic potential, making them key players in biological analysis and biomedical applications. To date, a variety of applications have been demonstrated with FNA-based hydrogels, including biosensing, environmental analysis, controlled drug release, cell adhesion and targeted cancer therapy. In this review, we focus on advances in the development of FNA-based hydrogels, which have fully incorporated both the unique features of FNAs and DNA-based hydrogels. We first introduce different strategies for constructing DNA-based hydrogels. Subsequently, various types of FNAs and the most recent developments of FNA-based hydrogels for bioanalytical and biomedical applications are described with some selected examples. Finally, the review provides an insight into the remaining challenges and future perspectives of FNA-based hydrogels.

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.

Gelatin carriers for drug and cell delivery in tissue engineering

The ability of gelatin to form complexes with different drugs has been investigated for controlled release applications. Gelatin parameters, such as crosslinking density and isoelectric point, have been tuned in order to optimize gelatin degradation and drug delivery kinetics. In recent years, focus has shifted away from the use of gelatin in isolation toward the modification of gelatin with functional groups and the fabrication of material composites with embedded gelatin carriers. In this review, we highlight some of the latest work being performed in these areas and comment on trends in the field. Specifically, we discuss gelatin modifications for immune system evasion, drug stabilization, and targeted delivery, as well as gelatin composite systems based on ceramics, naturally-occurring polymers, and synthetic polymers.

From rationally designed polymeric and peptidic systems to sophisticated gene delivery nano-vectors

Lack of safe, efficient and controllable methods for delivering therapeutic genes appears to be the most important factor preventing human gene therapy. Safety issues encountered with viral vectors have prompted substantial attention to in vivo investigations with non-viral vectors throughout the past decade. However, developing non-viral vectors with effectiveness comparable to viral ones has been a challenge. The strategy of designing multifunctional synthetic carriers targeting several extracellular and intracellular barriers in the gene transfer pathway has emerged as a promising approach to improving the efficacy of gene delivery systems. This review will explain how sophisticated synthetic vectors can be created by combining conventional polycationic vectors such as polyethylenimine and basic amino acid peptides with additional polymers and peptides that are designed to overcome potential barriers to the gene delivery process.

Preparation and characterization of gelatin nanoparticles containing pDNA encoding IL-12 and their expression in CT-26 carcinoma cells

Aim: Gelatin as a biodegradable, nontoxic and biocompatible natural protein is a good candidate for gene delivery. In this study, pDNA-loaded gelatin nanoparticles were prepared and characterized for the expression of the cytokine IL-12 and anti-tumor effects. Materials & methods: Gelatin–pUMVC3–hIL-12 nanoparticles were prepared by the ethanol precipitation technique and evaluated for physicochemical characteristics, cytotoxiciy and transfection efficiency. Results: The prepared particles were spherical in shape with sizes varying from 344.27 to 826.23 nm, ζ-potentials between -944 and -165 mV, and greater than 97% encapsulation efficiency. The particles were nontoxic to CT-26 carcinoma cells. The nanoparticles prepared using 0.5% gelatin solution (G14) with a mean particle size of 816.87 nm (polydispersity index = 0.56 ± 0.01) demonstrated maximum transfection efficiency with 2.5-times higher expression compared with the naked plasmid. Conclusion: Gelatin–DNA nanoparticles using 0.5% gelatin solution had minimal cytotoxicity and can be used as a suitable candidate for further gene delivery studies and applications.

Intraperitoneal delivery of nanoparticles for cancer gene therapy

Nanoparticle-based gene delivery systems may be more efficient for administration of therapeutic genes to solid tumors and cancer metastases, owing to the numerous advantages in terms of enhanced tissue penetrability, improved cellular uptake and targeted gene delivery to the cells of interest compared with other gene delivery systems. Intraperitoneal (IP) delivery of therapeutic agents offers special merits because of the anatomical situation of peritoneum for local cancer therapy. Via the IP administration route, it is possible to target the therapeutic agents exactly to the target cells and protect healthy tissues outside the peritoneal cavity from side effects. IP delivery could be applicable for the treatment of disorders of organs in the peritoneal cavity covered with peritoneum and subperitoneal connective tissue, including cancers such as ovarian and gastric. The goal of this article is to review the current state of IP delivery of nanoparticles for cancer gene therapy.

The huge world of small RNAs: regulating networks of microRNAs (review)

MicroRNAs (miRNAs) are a recently discovered class of small, non-coding RNAs which do not code proteins. MiRNAs regulate gene expression by inhibiting protein translation from the messenger RNA. MiRNAs may function in networks, forming a complex relationship with diseases. Furthermore, specific miRNAs have significant correlation with diseases of divergent origin. After identification of disease-associated miRNAs, their tissue expression could be altered in a beneficial way by inhibiting or mimicking their effects. Thus, modifying the expression of miRNAs is a potential future gene-therapeutic tool to influence post-transcriptional regulation of multiple genes in a single therapy. In this review we introduce the biogenesis, mechanism of action and future aspects of miRNAs. Research on the post-transcriptional regulation of gene expression by miRNA may reshape our understanding of diseases and consequently may bring new diagnostic markers and therapeutic agents. Therapeutic use of miRNAs is already under clinical investigation in RNA interference trials.

p53-targeted cancer pharmacotherapy: move towards small molecule compounds

OBJECTIVES

For the past three decades of research, p53 has been identified as one of the most targetable molecules for developing anticancer treatments. This tumour suppressor protein is involved in apoptosis, cell cycle arrest and senescence. A wide range of pharmaceutical drugs and radiotherapy treatments activate this protein and rely on p53 signalling for therapeutic outcome. Promising small molecular weight compounds, some of which are undergoing clinical trials, are discussed in this review.

KEY FINDINGS

The spectrum of potential therapeutic approaches trialled for p53 stretch from gene therapy to the more recent development of small molecules capable of activating wild-type p53 or reactivating mutant p53.

SUMMARY

Our ever-growing knowledge leads us to better understand this protein, from its structure and activities to its potential therapeutic application, firstly for cancer and then for other diseases and maybe even for reversal of ageing.

Polymeric drug delivery systems for localized cancer chemotherapy

Cancer has become one of the most difficult health challenges of our time, accounting for millions of deaths yearly. Systemic chemotherapy is the most common therapeutic approach; however, considerable limitations exist including toxicities to healthy tissues and low achievable drug concentrations at tumor sites. More than 85% of human cancers are solid tumors, which can greatly benefit from localized delivery. This approach allows for high drug concentrations at the target site, lower systemic toxicity, and extended drug exposure which may be beneficial for cell cycle-specific drugs. Polymers have been widely considered in the development of localized delivery systems. This review focuses on both natural and synthetic biodegradable polymers that have been explored for localized chemotherapy, exploring their advantages, disadvantages, and clinical potential while citing examples of their use in pre-clinical development.