Incorporation of Plant Extracted Hydroxyapatite and Chitosan Nanoparticles on the Surface of Orthodontic Micro-Implants: An In-Vitro Antibacterial Study

Chitosan and Its Nanoparticles: A Multifaceted Approach to Antibacterial Applications

Chitosan, a multifaceted amino polysaccharide biopolymer derived from chitin, has extensive antibacterial efficacy against diverse pathogenic microorganisms, including both Gram-negative and Gram-positive bacteria, in addition to fungi. Over the course of the last several decades, chitosan nanoparticles (NPs), which are polymeric and bio-based, have garnered a great deal of interest as efficient antibacterial agents. This is mostly due to the fact that they are used in a wide variety of applications, including medical treatments, food, chemicals, and agricultural products. Within the context of the antibacterial mechanism of chitosan and chitosan NPs, we present a review that provides an overview of the synthesis methods, including novel procedures, and compiles the applications that have been developed in the field of biomedicine. These applications include wound healing, drug delivery, dental treatment, water purification, agriculture, and food preservation. In addition to this, we focus on the mechanisms of action and the factors that determine the antibacterial activity of chitosan and its derivatives. In conjunction with this line of inquiry, researchers are strongly urged to concentrate their efforts on developing novel and ground-breaking applications of chitosan NPs.

Advances of Hydroxyapatite Nanoparticles in Dental Implant Applications

Hydroxyapatite nanoparticles (HANPs) are becoming increasingly crucial in dental implant applications as they are highly compatible with biological systems, actively support biological processes, and closely resemble bone minerals. This review covers the latest progress in how HANPs are made, studied, and used in dentistry. It looks at critical methods for creating HANPs, such as sol-gel, microwave hydrothermal synthesis, and biomimetic approaches, and how they affect the particles' size, structure, and activity. The green synthesis method illustrated a new door to synthesize HAp for maintaining biocompatibilityand increasing antibacterial properties. The review also explores how HANPs improve the integration of implants with bone, support bone growth, and help treat sensitive teeth based on various laboratory and clinical studies. The usage of HAp in dentin and enamel shows higher potentiality through FTIR, XPS, XRD, EDS, etc., for mechanical stability and biological balance compared to natural teeth. Additionally, the use of HANPs in dental products like toothpaste and mouthwash is discussed, highlighting its potential to help rebuild tooth enamel and fight bacteria. There are some challenges for long-term usage against oral bacteria, but doping with inorganic materials, like Zn, has already solved this periodontal problem. Much more research is still essential to estimate the fabrication variation based on patient problems and characteristics. Still, it has favorable outcomes regarding its bioactive nature and antimicrobial properties. Due to their compatibility with biological tissues and ability to support bone growth, HANPs hold great promise for advancing dental materials and implant technology, potentially leading to better dental care and patient outcomes.

Antibacterial and anticancer activities of three novel lectin-conjugated chitosan nanoparticles

To the best of our knowledge, this is the first attempt to synthesize, characterize, and determine the antibacterial and anticancer effects of three novel conjugates of plant lectins: phytohemagglutinin lectin (PHA), soybean agglutinin (SBA), and peanut agglutinin (PNA) with chitosan nanoparticles (CHNPs). The lectin concentration within prepared conjugates was estimated using nannodrop, and the highest concentration was 0.96 mg/ml in PHA-CHNPs. SDS-PAGE showed the molecular weights of conjugates ranged from 26.9 to 63.9 kDa. UV spectrophotometer recorded the absorbance peaks of conjugates somewhere between 200 and 230 nm. Hemagglutination analysis verified the presence of actively binding lectins. The three conjugates showed strong antibacterial activity against Gram-positive and Gram-negative bacteria compared to pure lectins and chitosan nanoparticles. The highest inhibition zone was 55.67 ± 4.04, 38.67 ± 5.51, and 37.33 ± 2.52 for PHA-CHNPs against Enterococcus faecalis, Salmonella typhimurium, and Shigella sonnei, respectively, followed by 36.3 ± 0.15 for PNA-CHNPs against Staphylococcus aureus. The lowest MIC was 1.5 µg/ml for PHA-CHNPs against Enterococcus faecalis, followed by 12 µg/ml for PNA-CHNPs and SBA-CHNPs against Salmonella typhimurium and Enterococcus faecalis, respectively. TEM microphotographs show the conjugation pattern between lectins and chitosan nanoparticles and the morphological differences between control, treated bacteria, and cancer cells. Moreover, 100 μg/ml of PHA-CHNPs affect tongue carcinoma (HNO-97), colorectal cancer (HT-29), and human melanoma (A375) cancer cell lines, reducing cell viability by 38.78 ± 1.85%, 49.88 ± 1.11%, and 66.92 ± 3.60%, respectively. This study develops three innovative conjugates of lectin chitosan nanoparticles that need to be tested as potential antibacterial and anticancer agents for medical and cancer therapy applications. KEY POINTS: • Lectin-conjugated chitosan nanoparticles exhibit antibacterial activity. • All conjugates are safe for oral epithelial cells and human skin fibroblasts. • The PHA-CHNP conjugates have anticancer activity against HNO-97, HT-29, and A375.

Synthesis and in vitro characteristics of biogenic-derived hydroxyapatite for bone remodeling applications

The inorganic component of bone matrix, hydroxyapatite (HAp) (with formula Ca10(PO4)6(OH)2), can be obtained from inexpensive waste resources that serve as excellent calcium precursors. In the present study, HAp nano-powder was synthesized from eggshells (ES) and crab shells (CS) by wet chemical precipitation method. Also, a hybrid sample was considered which is a mixture of HAp nano-powder synthesized from eggshells (25%) and crab shells (75%) (EC). The presence of phosphate, carbonate, and hydroxyl groups in the synthesized powder was confirmed through FTIR analysis. The phase composition was determined using XRD, and elemental analysis revealed a Ca/P ratio ranging from 1.5 to 1.8, confirming the HAp nature of the nano-powder, which ranged in size from 73 to 375 nm. Importantly, preliminary in vitro tests were conducted using mouse preosteoblast cell line MC3T3-E1 to evaluate the cytotoxic effects of the synthesized HAp. The results indicated excellent biocompatibility. Moreover, sample EC exhibited a significantly higher proliferation on days 3, 6, 9, and 12. EC demonstrated promising antimicrobial properties by exhibiting a significantly higher inhibitory effect against the bacteria Streptococcus mutans and Escherichia coli, and the fungi Candida albicans and Aspergillus niger. Additionally, EC displayed notable antioxidant activity, with IC50 values of 271.543 µg/ml and 407.764 µg/ml in DPPH and H2O2 assays, respectively. Furthermore, it showed strong anti-inflammatory properties, with a dose-dependent inhibition against protein denaturation. Given these findings, the synthesized HAp holds promise as a potential bone filler and could be beneficial for bone remodeling applications.

The Importance of Chitosan Coatings in Dentistry

A Chitosan is a copolymer of N-acetyl-D-glucose amine and D-glucose amine that can be easily produced. It is a polymer that is widely utilized to create nanoparticles (NPs) with specific properties for applications in a wide range of human activities. Chitosan is a substance with excellent prospects due to its antibacterial, anti-inflammatory, antifungal, haemostatic, analgesic, mucoadhesive, and osseointegrative qualities, as well as its superior film-forming capacity. Chitosan nanoparticles (NPs) serve a variety of functions in the pharmaceutical and medical fields, including dentistry. According to recent research, chitosan and its derivatives can be embedded in materials for dental adhesives, barrier membranes, bone replacement, tissue regeneration, and antibacterial agents to improve the management of oral diseases. This narrative review aims to discuss the development of chitosan-containing materials for dental and implant engineering applications, as well as the challenges and future potential. For this purpose, the PubMed database (Medline) was utilised to search for publications published less than 10 years ago. The keywords used were "chitosan coating" and "dentistry". After carefully selecting according to these keywords, 23 articles were studied. The review concluded that chitosan is a biocompatible and bioactive material with many benefits in surgery, restorative dentistry, endodontics, prosthetics, orthodontics, and disinfection. Furthermore, despite the fact that it is a highly significant and promising coating, there is still a demand for various types of coatings. Chitosan is a semi-synthetic polysaccharide that has many medical applications because of its antimicrobial properties. This article aims to review the role of chitosan in dental implantology.

Mercuric-sulphide based metallopharmaceutical formulation as an alternative therapeutic to combat viral and multidrug-resistant (MDR) bacterial infections

According to the Global Antimicrobial Resistance and Use Surveillance System (GLASS) data, antibiotic resistance escalates more challenges in treatment against communicable diseases worldwide. Henceforth, the use of combinational antimicrobial therapy and metal-conjugated phytoconstituents composites are considered as alternatives. The present study explored the efficacy of mercuric-sulfide-based metallopharmaceutical, Sivanar Amirtham for anti-bacterial, anti-tuberculosis, anti-HIV therapeutics and toxicity profile by haemolytic assay, first of its kind. The anti-bacterial study was performed against both gram-positive and gram-negative pathogens including Staphylococcus aureus (ATCC 29213), Methicillin-resistant Staphylococcus aureus (MRSA: ATCC 43300), Enterococcus faecalis (ATCC 29212), Pseudomonas aeruginosa (PA14) and Vibrio cholerae (MTCC 3905) by agar well diffusion assay, wherein the highest zone of inhibition was identified for MRSA (20.7 mm) and V. cholerae (34.3 mm) at 25 mg/mL. Furthermore, the anti-tuberculosis activity experimented by microtitre alamar blue assay against M. tuberculosis (ATCC 27294) demonstrated significant activity at the concentration range of 12.5-100 µg/mL. Additionally, the anti-HIV efficacy established by the syncytia inhibition method using C8166 cell lines infected with HIV-1IIIB, showed a significant therapeutic effect. The in-vitro toxicity assay proved Sivanar Amirtham to be non-haemolytic and haemocompatible. The physicochemical characterization studies revealed the nano-sized particles with different functional groups and the distinctive metal-mineral complex could be attributed to the multi-site targeting ability. The rationale evidence and scientific validation for the efficacy of Sivanar Amirtham ensures that it could be proposed as an alternative or adjuvant for both prophylactics and therapeutics to overcome HIV infection and antimicrobial resistance as well as the multi-drug resistance challenges.

Bioresorbable Chitosan-Based Bone Regeneration Scaffold Using Various Bioceramics and the Alteration of Photoinitiator Concentration in an Extended UV Photocrosslinking Reaction

Bone tissue engineering (BTE) is an ongoing field of research based on clinical needs to treat delayed and non-union long bone fractures. An ideal tissue engineering scaffold should have a biodegradability property matching the rate of new bone turnover, be non-toxic, have good mechanical properties, and mimic the natural extracellular matrix to induce bone regeneration. In this study, biodegradable chitosan (CS) scaffolds were prepared with combinations of bioactive ceramics, namely hydroxyapatite (HAp), tricalcium phosphate-α (TCP- α), and fluorapatite (FAp), with a fixed concentration of benzophenone photoinitiator (50 µL of 0.1% (w/v)) and crosslinked using a UV curing system. The efficacy of the one-step crosslinking reaction was assessed using swelling and compression testing, SEM and FTIR analysis, and biodegradation studies in simulated body fluid. Results indicate that the scaffolds had comparable mechanical properties, which were: 13.69 ± 1.06 (CS/HAp), 12.82 ± 4.10 (CS/TCP-α), 13.87 ± 2.9 (CS/HAp/TCP-α), and 15.55 ± 0.56 (CS/FAp). Consequently, various benzophenone concentrations were added to CS/HAp formulations to determine their effect on the degradation rate. Based on the mechanical properties and degradation profile of CS/HAp, it was found that 5 µL of 0.1% (w/v) benzophenone resulted in the highest degradation rate at eight weeks (54.48% degraded), while maintaining compressive strength between (4.04 ± 1.49 to 10.17 ± 4.78 MPa) during degradation testing. These results indicate that incorporating bioceramics with a suitable photoinitiator concentration can tailor the biodegradability and load-bearing capacity of the scaffolds.