Use of Chitosan as a Precursor for Multiple Applications in Medicinal Chemistry: Recent Significant Contributions

Chitosan (CS) is a polymer made up of mainly deacetylated β-1,4 D-glucosamine units, which is part of a large group of D-glucosamine oligomers known as chitooligosaccharides, which can be obtained from chitin, most abundant natural polymer after cellulose and central component of the shrimp exoskeleton. It is known that it can be used for the development of materials, among which its use stands out in wastewater treatment (removal of metal ions, dyes, and as a membrane in purification processes), food industry (anti-cholesterol and fat, packaging material, preservative, and food additive), agriculture (seed and fertilizer coating, controlled release agrochemicals), pulp and paper industry (surface treatment, adhesive paper), cosmetics (body creams, lotions, etc.), in the engineering of tissues, wound healing, as excipients for drug administration, gels, membranes, nanofibers, beads, microparticles, nanoparticles, scaffolds, sponges, and diverse biological ones, specifically antibacterial and antifungal activities. This article reviews the main contributions published in the last ten years regarding the use and application of CS in medical chemistry. The applications exposed here involve regenerative medicine in the design of bioprocesses and tissue engineering, Pharmaceutical sciences to obtain biomaterials, polymers, biomedicine, and the use of nanomaterials and nanotechnology, toxicology, and Clinical Pharmaceuticals, emphasizing the perspectives and the direction that can take research in this area.

Chitosan-based Schiff bases: Promising materials for biomedical and industrial applications

There is plenty of scope for modifying chitosan, an only polycationic natural polysaccharide, owing to its reactive functional groups, namely hydroxyl and amino groups. Although innumerable numbers of chitosan derivatives have been synthesized by modifying these groups and reported elsewhere, in this review article, an attempt has been exclusively made to demonstrate the syntheses of various chitosan-based Schiff bases (CSBs) simply by allowing the reactions of reactive amino groups of chitosan with different aldehydes/ketones of interest. Due to their very peculiar and unique characteristics, such as biodegradability, biocompatibility, metal-binding capability, etc., they are found to be very useful for diversified applications. Thus, we have also attempted to showcase their very specific biomedical fields, including tissue engineering, drug delivery, and wound healing, to name a few. In addition, we have also discussed the utilization of CSBs for industrial applications such as wastewater treatment, catalysis, corrosion inhibition, sensors, etc.

Multifunctional nanoparticles for the treatment and diagnosis of osteosarcoma

Osteosarcoma (OS) is a common primary malignant bone tumor in adolescents. Currently, the commonly used treatment strategies for OS include surgery, chemotherapy and radiotherapy. However, these methods have some problems that cannot be ignored, such as postoperative sequelae and severe side effects. Therefore, in recent years, researchers have been looking for other means to improve the treatment or diagnosis effect of OS and increase the overall survival rate of patients. With the development of nanotechnology, nanoparticles (NPs) have presented excellent properties in improving the therapeutic efficacy of drugs for OS. Nanotechnology makes it possible for NPs to combine various functional molecules and drugs to achieve multiple therapeutic effects. This review presents the important properties of multifunctional NPs for the treatment and diagnosis of OS and focuses on the research progress of common NPs applied for drug or gene delivery, phototherapy and diagnosis of OS, such as carbon-based quantum dots, metal, chitosan and liposome NPs. Finally, the promising prospects and challenges of developing multifunctional NPs with enhanced efficacy are discussed, which lays the foundation and direction for improving the future therapeutic and diagnostic methods of OS.

Osteogenic differentiation of human adipose-derived mesenchymal stem cells in a bisphosphonate-functionalized polycaprolactone/gelatin scaffold

Recent trends in bone tissue engineering have focused on the development of biomimetic constructs with appropriate mechanical and physiochemical properties. Here, we report the fabrication of an innovative biomaterial scaffold based on a new bisphosphonate-containing synthetic polymer combined with gelatin. To this end, zoledronate (ZA)-functionalized polycaprolactone (PCL-ZA) was synthesized by a chemical grafting reaction. After adding gelatin to the PCL-ZA polymer solution, the porous PCL-ZA/gelatin scaffold was fabricated by the freeze-casting method. A scaffold with aligned pores and a porosity of 82.04 % was obtained. During in vitro biodegradability test, 49 % of its initial weight lost after 5 weeks. The elastic modulus of the PCL-ZA/gelatin scaffold was 31.4 MPa, and its tensile strength was 4.2 MPa. Based on the results of MTT assay, the scaffold had good cytocompatibility with human Adipose-Derived Mesenchymal Stem Cells (hADMSCs). Furthermore, cells grown in PCL-ZA/gelatin scaffold showed the highest mineralization and ALP activity compared to other test groups. Results of the RT-PCR test revealed that RUNX2, COL 1A1, and OCN genes were expressed in PCL-ZA/gelatin scaffold at the highest level, suggesting its good osteoinductive capacity. These results revealed that PCL-ZA/gelatin scaffold could be considered a proper biomimetic platform for bone tissue engineering.

Modification and Functionalization of Polymers for Targeting to Bone Cancer and Bone Regeneration

Bone is one of the most complex, inaccessible body structures, responsible for calcium storage and haematopoiesis. The second highest cause of death across the world is cancer. Amongst all the types of cancers, bone cancer treatment modalities are limited due to the structural complexity and inaccessibility of bones. The worldwide incidence of bone diseases and bone defects due to cancer, infection, trauma, age-related bone degeneration is increasing. Currently different conventional therapies are available for bone cancer such as chemotherapy, surgery and radiotherapy, but they have several disadvantages associated with them. Nanomedicine is being extensively researched as viable therapeutics to mitigate drug resistance in cancer therapy and promote bone regeneration. Several natural polymers such as chitosan, dextran, alginate, hyaluronic acid, and synthetic polymers like polyglycolic acid, poly(lactic-co-glycolic acid), polycaprolactone are investigated for their application in nanomedicine for bone cancer treatment and bone regeneration. Nanocarriers have shown promising results in preclinical experimental studies. However, they still face a major drawback of inadequate targetability. The paper summarizes the status of research and the progress made so far in modifications and functionalization of natural polymers for improving their site specificity and targeting for effective treatment of bone cancer and enhancing bone regeneration.

Hydroxyapatite Biobased Materials for Treatment and Diagnosis of Cancer

Great advances in cancer treatment have been undertaken in the last years as a consequence of the development of new antitumoral drugs able to target cancer cells with decreasing side effects and a better understanding of the behavior of neoplastic cells during invasion and metastasis. Specifically, drug delivery systems (DDS) based on the use of hydroxyapatite nanoparticles (HAp NPs) are gaining attention and merit a comprehensive review focused on their potential applications. These are derived from the intrinsic properties of HAp (e.g., biocompatibility and biodegradability), together with the easy functionalization and easy control of porosity, crystallinity and morphology of HAp NPs. The capacity to tailor the properties of DLS based on HAp NPs has well-recognized advantages for the control of both drug loading and release. Furthermore, the functionalization of NPs allows a targeted uptake in tumoral cells while their rapid elimination by the reticuloendothelial system (RES) can be avoided. Advances in HAp NPs involve not only their use as drug nanocarriers but also their employment as nanosystems for magnetic hyperthermia therapy, gene delivery systems, adjuvants for cancer immunotherapy and nanoparticles for cell imaging.

Chitosan-based biomaterials for the treatment of bone disorders

Bone is an alive and dynamic organ that is well-differentiated and originated from mesenchymal tissues. Bone undergoes continuous remodeling during the lifetime of an individual. Although knowledge regarding bones and their disorders has been constantly growing, much attention has been devoted to effective treatments that can be used, both from materials and medical performance points of view. Polymers derived from natural sources, for example polysaccharides, are generally biocompatible and are therefore considered excellent candidates for various biomedical applications. This review outlines the development of chitosan-based biomaterials for the treatment of bone disorders including bone fracture, osteoporosis, osteoarthritis, arthritis rheumatoid, and osteosarcoma. Different examples of chitosan-based formulations in the form of gels, micro/nanoparticles, and films are discussed herein. The work also reviews recent patents and important developments related to the use of chitosan in the treatment of bone disorders. Although most of the cited research was accomplished before reaching the clinical application level, this manuscript summarizes the latest achievements within chitosan-based biomaterials used for the treatment of bone disorders and provides perspectives for future scientific activities.

Calcium Phosphate-Based Bioceramics in the Treatment of Osteosarcoma: Drug Delivery Composites and Magnetic Hyperthermia Agents

The use of biomaterials in medicine is not recent, and in the last few decades, the research and development of biocompatible materials had emerged. Hydroxyapatite (HAp), a calcium phosphate that constitutes a large part of the inorganic composition of human bones and teeth, has been used as an interesting bioceramic material. Among its applications, HAp has been used to carry antitumor drugs, such as doxorubicin, cisplatin, and gemcitabine. Such HAp-based composites have an essential role in anticancer drug delivery systems, including the treatment of osteosarcoma. In addition, the association of this bioceramic with magnetic nanoparticles (MNPs) has also been used as an effective agent of local magnetic hyperthermia. Further, the combined approach of the aforementioned techniques (HAp scaffolds combined with anti-tumor drugs and MNPs) is also an attractive therapeutical alternative. Considering the promising role of the use of bioceramics in modern medicine, we proposed this review, presenting an updated perspective on the use of HAp in the treatment of cancer, especially osteosarcoma. Finally, after giving the current progress in this field, we highlight the urgent need for efforts to provide a better understanding of their potential applications.

Biofunctional phosphorylated magnetic scaffold for bone tissue engineering

The development of highly bioactive engineered scaffolds is required to promote bone regeneration and the success of bone tissue engineering treatment approaches. This study attempts to fabricate a biofunctional magnetic scaffold based on new phosphorylated polycaprolactone combined with gelatin (MNPs-PCL-P/gelatin). Phosphorylated polymer and magnetic nanoparticles (MNPs) were synthesized and characterized by NMR, FT-IR, TEM, and DLS instruments. The synthetic polymer, MNPs, and biopolymer were mixed then freeze-dried to prepare a porous scaffold. Physiochemical assessments showed that a scaffold with well-developed porous morphology, and stable structure was obtained. MNPs-PCL-P/gelatin scaffold had no toxicity on human dental pulp stem cells (hDPSCs). The use of phosphorous-containing polymer resulted in improvement of the scaffold's osteoconductivity to support proper cell attachment and promote cell proliferation. Phosphate group by mimicking function of bone phosphate groups stimulate bone mineralization that reflected by alizarin red S staining assay. The presence of MNPs resulted in higher ALP activity and increased expression level of RUNX2, BMP2 osteogenic biomarkers. Also, phosphorylation enhanced osteoinductivity of scaffold and upregulate RUNX2, BMP2, COL1A1, and OCN genes in phosphors-containing scaffold test groups. It seems that biocompatible MNPs-PCL-P/gelatin scaffold possesses the potential of applications in bone tissue engineering.

Natural Drug-Loaded Bimetal-Substituted Hydroxyapatite-Polymeric Composite for Osteosarcoma-Affected Bone Repair

Repairing segmental bone deformities after resection of dangerous bone tumors is a long-standing clinical issue. The study's main objective is to synthesize a natural bioactive compound-loaded bimetal-substituted hydroxyapatite (BM-HA)-based composite for bone regeneration. The bimetal (copper and cadmium)-substituted HAs were prepared by the sol-gel method and reinforced with biocompatible polyacrylamide (BM-HA/PAA). Umbelliferone (UMB) drug was added to the BM-HA/PAA composite to enhance anticancer activity further. The composite's formation was confirmed by various physicochemical investigations, such as FT-IR, XRD, SEM, EDAX, and HR-TEM techniques. The bioactivity was assessed by immersing the sample in simulated body fluid for 1, 3, and 7 days. The zeta potential values of BM-HA/PAA and BM-HA/PAA/UMB are -36.4 mV and -49.4 mV, respectively. The in vitro viability of the prepared composites was examined in mesenchymal stem cells (MSCs). It shows the ability of the composite to produce osteogenic bone regeneration without any adverse effects. From the gene expression and PCR results, the final UMB-loaded composite induced osteogenic markers, such as Runx, OCN, and VEFG. The prepared bimetal substituted polyacrylamide reinforced HA composite loaded with UMB drug has the ability for bone repair/regenerations.

Nanocarrier-based drug delivery systems for bone cancer therapy: a review

Bone cancer is a malignant tumor that originates in the bone and destroys the healthy bone tissues. Of the various types of bone tumors, osteosarcoma is the most commonly diagnosed primary bone malignancy. The standard treatment for primary malignant bone tumors comprises surgery, chemotherapy and radiotherapy. Owing to the lack of proven treatments, different forms of alternative therapeutic approaches have been examined in recent decades. Among the new therapeutic methodologies, nanotechnology-based anticancer therapy has paved the way for new targeted strategies for bone cancer treatment and bone regeneration. They include approaches such as the co-delivery of multiple drug cargoes, the enhancement of their biodistribution and transport properties, normalizing accumulation and the optimization of drug release profiles to overcome shortcomings of the existing therapy. This review examines the standard treatments for osteosarcoma, their lacunae, and the evolving therapeutic strategies based on nanocarrier-mediated combinational drug delivery systems, and future perspectives for osteosarcoma therapy.

The study on calcium polyphosphate/poly-amino acid composite for supportive bone substitute materials in vitro

A poly-amino acid/calcium polyphosphate composite with high mechanical strength, excellent stability and biological activity was prepared and studied for bone-repaired.

The osteogenic and bacterial inhibition potential of natural and synthetic compound loaded metal–ceramic composite coated titanium implant for orthopedic applications

Schematic illustration of the preparation, electrophoretic deposition, antibacterial and osteogenic bone regeneration abilities of the MHAP/ChN/GGe/GTN composite. Where, the green colored shape with red, yellow and blue spheres indicates the GGe.

Phosphorylated Chitosan Hydrogels Inducing Osteogenic Differentiation of Osteoblasts via JNK and p38 Signaling Pathways

Phosphorous-containing biopolymers have been applied to expedite the regeneration of damaged bone tissue by stimulating the function of phosphorous groups in natural bones. However, the underlying mechanism of phosphorous-containing biopolymers in promoting osteogenic differentiation is unclarified. Herein, we synthesized phosphorylated chitosan hydrogels by incorporating phosphocreatine into chitosan molecular chains under mild conditions. The introduction of phosphate groups improved properties of protein adsorption and calcium deposition without affecting the morphology of hydrogels. Our results showed that phosphorylated chitosan hydrogels could not only promote alkaline phosphatase activity and mineralization but also upregulate the expression of osteogenic-related genes and proteins. Meanwhile, application of c-Jun N-terminal kinase inhibitor SP600125 and p38 mitogen-activated protein kinase inhibitor SB203580 repressed the expression of osteogenic-related markers in gene and protein levels. To the best of our knowledge, it is reported for the first time that phosphorous-containing biopolymers promote osteogenic differentiation of osteoblasts via JNK and p38 signaling pathways.

In Vivo Assessment of a Hydroxyapatite/κ-Carrageenan-Maleic Anhydride-Casein/Doxorubicin Composite-Coated Titanium Bone Implant

Here, we focus on the fabrications of an osteosarcoma implant for bone repair via the development of a hydroxyapatite/κ-carrageenan-maleic anhydride/casein with doxorubicin (HAP/κ-CA-MA-CAS/DOX) composite-deposited titanium (Ti) plate. The HAP/κ-CA-MA-CAS/DOX material was coated on the Ti plate through the EPD method (electrophoretic deposition), applying direct current (DC) signals to deposit the composite on the surface of the Ti plate. The physicochemical and morphological possessions and biocompatibility in vitro of the prepared nanocomposite were examined to assess its prospective effectiveness for purposes of bone regeneration. Excellent biocompatibility and elevated osteoconductivity were confirmed using MG63 osteoblast-like cells. In vivo studies were performed at tibia sites in Wistar rats, and rapid bone regeneration was detected at four weeks in defective bone. Overall, the studies demonstrate that the HAP/κ-CA-MA-CAS/DOX composite enhances the biocompatible and cell-stimulating biointerface of Ti metallic implants. As such, HAP/κ-CA-MA-CAS/DOX implants are viable prospects for osteosarcoma-affected bone regeneration.

Presentation of Antibacterial and Therapeutic Anti-inflammatory Potentials to Hydroxyapatite via Biomimetic With Azadirachta indica: An in vitro Anti-inflammatory Assessment in Contradiction of LPS-Induced Stress in RAW 264.7 Cells

In the present study, for the first time, biomimetization of hydroxyapatite (HA) with Azadirachta indica (AI) was proposed and established its antioxidant, antibacterial, and anti-inflammatory potential on lipopolysaccharide (LPS). The ethanolic extract of AI was found rich with phenolics and flavonoids, and determined their concentration as 8.98 ± 1.41 mg gallic acid equivalents/g and 5.46 ± 0.84 mg catechin equivalents/g, respectively. The HA was prepared by sol-gel method from calcium nitrate tetrahydrate and orthophosphoric acid, and successfully biomimetization was performed with ethanolic extract of AI. The FTIR analysis settled that as-synthesized HA-AI composite was comprised of both HA and AI. The XRD pattern and Zeta potential revealed that the HA-AI composite was crystalline and negative in charge (-24.0 mV). The average-size distribution, shape, and size of the HA-AI composite was determined as 238.90 d.nm, spherical, and 117.90 nm from size distribution, SEM, and HR-TEM analysis, respectively. The SEM-EDX concluded that the HA-AI composite was comprised of elements of HA as well as AI. The HA-AI composite presented potential antioxidant activity and its EC50 values (dose required to inhibit about half of the radicals) for ABTS and DPPH assays were determined as 115.72 ± 2.33 and 128.51 ± 1.04 μg/ml, respectively. The HA-AI composite showed potent antibacterial activity, and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) towards S. aureus (ATCC 700699) and E. coli (ATCC 10536) were correspondingly determined as 266.7 ± 28.87 and 600.0 ± 50.0 μg/ml, and 400.0 ± 86.6 and 816.7 ± 76.38 μg/ml. Most importantly, HA-AI composite presented the potential anti-inflammatory response toward lipopolysaccharide (LPS) in RAW 264.7 cells. The dose of 250 μg/ml of HA-AI composite has shown optimum protection against LPS-induced stress (1 μg/ml) by scavenging oxidants and regulating mitochondrial membrane potential (MMP), inflammatory and apoptotic factors. Thus, this study concluded that the impartation of potential biofunctional features to HA from plant sources through biomimetic approach is much beneficial and could find potential application in dentistry and orthopedic.

Fabrication of bioactive rifampicin loaded κ-Car-MA-INH/Nano hydroxyapatite composite for tuberculosis osteomyelitis infected tissue regeneration

Biocompatible polymers and ceramic materials have been identified as vital components to fabricate drug delivery and tissue engineering applications because of their high drug loading capability, sustained release and higher mechanical strength with remarkable in-vivo bioavailability. In the present work, initially we designed κ-carrageenan grafted with maleic anhydride and then reacted it with isoniazid drug (κ-Car-MA-INH). The polymeric system was cross linked with nanohydroxyapatite (NHAP) via electrostatic interaction followed by the addition of rifampicin (RF) and loaded to fabricate κ -Car-MA-INH/NHAP/RF nanocomposites. The chemical modification and interaction of drug with the polymeric-ceramic system were characterised by Fourier Transform Infrared spectroscopy (FT-IR). The zeta potential of the κ -Car-MA-INH/NHAP/RF nanocomposite was observed to be -20.04 mV using Zetasizer. The in vitro drug release studies demonstrated that the nanocomposite releases 76% of RF and 82% of INH in 12 days at pH 5.5. Scanning Electron Microscope analysis revealed the structural deformation of Staphylococcus aureus and Klebsiella pneumoniae upon treatment with this nanocomposite. By using ex-vivo studies combined with physio-chemical characterization methods on the erythrocytes, L929 and MG-63 cell lines, this composite was found to be biocompatible, non-cytotoxic and inducing cell proliferation with less significant hemolysis. Thus, our modified drug delivery nanocomposites afforded higher drug bioavailability with large potential for fabrication as long-acting drug delivery nanocomposites, especially with hydrophobic drugs inducing the growth of osteoblastic bone cells.

A phosphorylated chitosan armed hydroxyapatite nanocomposite for advancing activity onosteoblastandosteosarcomacells

Recently, applications of traditional medicine in tissue engineering have gained increasing attention.