Injectable thermosensitive chitosan/gelatin hydrogel for dental pulp stem cells proliferation and differentiation

Recent advancements in hydrogels as novel tissue engineering scaffolds for dental pulp regeneration

Although conventional root canal treatment offers an effective therapeutic solution, it negatively affects the viability of the affected tooth. In recent years, pulp regeneration technology has emerged as a novel method for treating irreversible pulpitis due to its ability to maintain tooth vitality. The successful implementation of this technique depends on scaffolds and transplantation of exogenous stem cells or recruitment of endogenous stem cells. Accordingly, the three-dimensional structure and viscoelastic characteristics of hydrogel scaffolds, which parallel those of the extracellular matrix, have generated considerable interest. Furthermore, hydrogels support the controlled release of regenerative drugs and to load a wide variety of bioactive molecules. By integrating antibacterial agents into the hydrogel matrix and stimulating an immune response, root canal disinfection can be significantly improved and the rate of pulp regeneration can be accelerated. This review aims to provide an overview of the clinical applications of hydrogels that have been reported in the last 5 years, and offer a comprehensive summary of the different approaches that have been utilized for the optimization of hydrogel scaffolds for pulp regeneration. Advancements and challenges in pulp regeneration using hydrogels treating aged teeth are discussed.

Preparation and characterization of a nanohydroxyapatite and sodium fluoride loaded chitosan-based in situ forming gel for enamel biomineralization

The development of remineralizing smart biomaterials is a contemporary approach to caries prevention. The present study aimed at formulation preparation and characterization of a thermoresponsive oral gel based on poloxamer and chitosan loaded with sodium fluoride (NaF) and nanohydroxyapatite (nHA) to treat demineralization. The chemical structure and morphology of the formulation were characterized using FTIR and FESEM-EDS tests. Hydrogel texture, rheology, and stability were also examined. The hydrogel was in a sol state at room temperature and became gel after being placed at 37 °C with no significance different in gelation time with the formulation without nHA and NaF as observed by t-test. The FTIR spectrum of nHA/NaF/chitosan-based hydrogel indicated the formation of physical crosslinking without any chemical interactions between the hydrogel components. The FESEM-EDS results demonstrated the uniform distribution of each element within the hydrogel matrix, confirming the successful incorporation of nHA and NaF in the prepared gel. The hardness, hydrogel's adhesiveness, and cohesiveness were 0.9 mJ, 1.7 mJ, and 0.37, respectively, indicating gel stability and the acceptable retention time of hydrogels. The formulation exhibited a non-Newtonian shear-thinning pseudoplastic and thixotropic behavior with absolute physical stability. Within the limitation of in vitro studies, nHA/NaF/chitosan-based in situ forming gel demonstrated favorable properties, which could be trasnsorm into a gel state in oral cavity due to poloxamer and chitosan and can prevent dental caries due to nHA and NaF. We propose this formulation as a promising dental material in tooth surface remineralization.

Dental delivery systems of antimicrobial drugs using chitosan, alginate, dextran, cellulose and other polysaccharides: A review

Dental caries, periodontal disease, and endodontic disease are major public health concerns worldwide due to their impact on individuals' quality of life. The present problem of dental disorders is the removal of the infection caused by numerous microbes, particularly, bacteria (both aerobes and anaerobes). The most effective method for treating and managing dental diseases appears to be the use of antibiotics or other antimicrobials, which are incorporated in some drug delivery systems. However, due to their insufficient bioavailability, poor availability for gastrointestinal absorption, and pharmacokinetics after administration via the oral route, many pharmaceutical medicines or natural bioactive substances have limited efficacy. During past few decades, a range of polysaccharide-based systems have been widely investigated for dental dug delivery. The polysaccharide-based carrier materials made of chitosan, alginate, dextran, cellulose and other polysaccharides have recently been spotlighted on the recent advancements in preventing, treating and managing dental diseases. The objective of the current review article is to present a brief comprehensive overview of the recent advancements in polysaccharide-based dental drug delivery systems for the delivery of different antimicrobial drugs.

Injectable hydrogels for cartilage and bone tissue regeneration: A review

Annually, millions of patients suffer from irreversible injury owing to the loss or failure of an organ or tissue caused by accident, aging, or disease. The combination of injectable hydrogels and the science of stem cells have emerged to address this persistent issue in society by generating minimally invasive treatments to augment tissue function. Hydrogels are composed of a cross-linked network of polymers that exhibit a high-water retention capacity, thereby mimicking the wet environment of native cells. Due to their inherent mechanical softness, hydrogels can be used as needle-injectable stem cell carrier materials to mend tissue defects. Hydrogels are made of different natural or synthetic polymers, displaying a broad portfolio of eligible properties, which include biocompatibility, low cytotoxicity, shear-thinning properties as well as tunable biological and physicochemical properties. Presently, novel ongoing developments and native-like hydrogels are increasingly being used broadly to improve the quality of life of those with disabling tissue-related diseases. The present review outlines various future and in-vitro applications of injectable hydrogel-based biomaterials, focusing on the newest ongoing developments of in-situ forming injectable hydrogels for bone and cartilage tissue engineering purposes.

Advanced nanoscale drug delivery systems for bone cancer therapy

Bone tumors are relatively rare, which are complex cancers and mostly involve the long bones and pelvis. Bone cancer is mainly categorized into osteosarcoma (OS), chondrosarcoma, and Ewing sarcoma. Of these, OS is the most intimidating cancer of the bone tissue, which is mostly found in the log bones in young children and older adults. Conspicuously, the current chemotherapy modalities used for the treatment of OS often fail mainly due to (i) the non-specific detrimental effects on normal healthy cells/tissues, (ii) the possible emergence of drug resistance mechanisms by cancer cells, and (iii) difficulty in the efficient delivery of anticancer drugs to the target cells. To impose the maximal therapeutic impacts on cancerous cells, it is of paramount necessity to specifically deliver chemotherapeutic agents to the tumor site and target the diseased cells using advanced nanoscale multifunctional drug delivery systems (DDSs) developed using organic and inorganic nanosystems. In this review, we provide deep insights into the development of various DDSs applied in targeting and eradicating OS. We elaborate on different DDSs developed using biomaterials, including chitosan, collagen, poly(lactic acid), poly(lactic-co-glycolic acid), polycaprolactone, poly(ethylene glycol), polyvinyl alcohol, polyethyleneimine, quantum dots, polypeptide, lipid NPs, and exosomes. We also discuss DDSs established using inorganic nanoscale materials such as magnetic NPs, gold, zinc, titanium NPs, ceramic materials, silica, silver NPs, and platinum NPs. We further highlight anticancer drugs' role in bone cancer therapy and the biocompatibility of nanocarriers for OS treatment.

Stimuli-responsive injectable chitosan-based hydrogels for controlled drug delivery systems

In the last decade, injectable hydrogels have attracted a lot of attention due to their excellent functional properties in the field of drug delivery for precise, non-invasive and focused tissue locations. Therefore, designing drug delivery systems (DDS) responsive to hydrogel stimuli to release a drug to an external stimulus with various advantages, can be very challenging. Due to their biocompatibility, mucosal adhesion, and hemostatic activity, chitosan (Chitosan)-based hydrogels offer a lot of potential for tissue engineering and drug delivery. It can be difficult to manage the structure of these stimuli-responsive CS hydrogels or they may require additional crosslinking agents, such as hydrogels with dual pH and thermo-responsiveness. Therefore, it is crucial to create these hydrogels for medicinal applications.