Synthesis, characterisation and biomedical applications of curcumin conjugated chitosan microspheres

Pharmacological effects, formulations, and clinical research progress of curcumin

Curcumin, a polyphenolic compound derived from the traditional Chinese medicine turmeric, which has a variety of pharmacological effects, including anti-cancer, anti-inflammatory, antioxidant, and antiviral properties. However, its clinical application is hindered by low solubility and bioavailability. To overcome these limitations, researchers have developed various formulations such as nanoformulations, solid dispersions, and microspheres. These advancements have led to improved therapeutic effects and have facilitated the progression of clinical research, primarily focusing on Phase I and Phase II trials for conditions like diabetes, obesity, and metabolic syndrome. In recent years, there has been a noticeable increase in Phase III and IV clinical trials, particularly concerning oral and dental diseases and arthritis. This article reviews recent literature from both domestic and international sources, providing a comprehensive overview of curcumin's research progress, including its pharmacological mechanisms, formulation developments, and clinical studies.

The bioconjugates of curcumin, zingerone and [6]-shogaol with low molecular weight chitosan: Synthesis, characterization and in vitro anticancer activity in HepG2 cells

The synthesis of bioconjugates of curcumin, zingerone, and [6]-shogaol with low molecular weight chitosan (LMWC) is presented. The unconjugated forms of these compounds exhibit low water solubility, poor stability, limited bioavailability, and low target specificity, whereas the synthetic conjugates demonstrate improved physical properties. The synthesis was achieved by forming succinates & then reacting with LMWC. They were characterized using FTIR, 1H NMR, UV-Vis spectroscopy, SEM and DLS analysis. The hydrophilicity of bioconjugates was found to be 10.66 mg/mL for C-LMWC, 17.67 mg/mL for Z-LMWC, and 11.59 mg/mL for S-LMWC. The bioconjugates exhibited enhanced stability compared to the individual compounds. In vitro release studies indicated a rapid release at pH 5.0 and a slower release at pH 7.4, which is favorable for cancer therapeutic applications. Additionally, the anticancer activity of the bioconjugates was evaluated using a cytotoxicity assay on the liver cancer cell line HepG2, displaying IC50 values of 14.01 μg/mL for C-LMWC, 82.53 μg/mL for Z-LMWC, and 9.07 μg/mL for S-LMWC. LMWC is superior to chitosan due to its hydrophilicity & low viscosity. The LMWC conjugates exhibited better solubility, stability and control release of bioactives. The study highlights a better anticancer activity of LMWC-conjugates compared to the native forms.

Biomaterials for neuroengineering: applications and challenges

Neurological injuries and diseases are a leading cause of disability worldwide, underscoring the urgent need for effective therapies. Neural regaining and enhancement therapies are seen as the most promising strategies for restoring neural function, offering hope for individuals affected by these conditions. Despite their promise, the path from animal research to clinical application is fraught with challenges. Neuroengineering, particularly through the use of biomaterials, has emerged as a key field that is paving the way for innovative solutions to these challenges. It seeks to understand and treat neurological disorders, unravel the nature of consciousness, and explore the mechanisms of memory and the brain's relationship with behavior, offering solutions for neural tissue engineering, neural interfaces and targeted drug delivery systems. These biomaterials, including both natural and synthetic types, are designed to replicate the cellular environment of the brain, thereby facilitating neural repair. This review aims to provide a comprehensive overview for biomaterials in neuroengineering, highlighting their application in neural functional regaining and enhancement across both basic research and clinical practice. It covers recent developments in biomaterial-based products, including 2D to 3D bioprinted scaffolds for cell and organoid culture, brain-on-a-chip systems, biomimetic electrodes and brain-computer interfaces. It also explores artificial synapses and neural networks, discussing their applications in modeling neural microenvironments for repair and regeneration, neural modulation and manipulation and the integration of traditional Chinese medicine. This review serves as a comprehensive guide to the role of biomaterials in advancing neuroengineering solutions, providing insights into the ongoing efforts to bridge the gap between innovation and clinical application.

Chemically modified chitosan as a functional biomaterial for drug delivery system

Chitosan is a natural polymer that can degrade in the environment and support green chemistry. It displays superior biocompatibility, easy access, and easy modification due to the reactive amino groups to transform or improve the physical and chemical properties. Chitosan can be chemically modified to enhance its properties, such as water solubility and biological activity. Modified chitosan is the most effective functional biomaterial that can be used to deliver the drugs to the targeted site. With diverse and versatile characteristics, it can be fabricated into various drug delivery systems such as membranes, beads, fibers, microparticles, composites, and scaffolds, for different drug delivery methods. Integrating nanotechnology with modified chitosan enhanced the delivery attributes of antibacterial, antifungal, antiviral, anticancer, anti-inflammatory, protein/peptides, and nucleic acids for intended use toward desired therapeutic outcomes. The review brings out an overview of the research regarding drug delivery systems utilizing modifying chitosan detailing the properties, functionality, and applications.

Pickering Emulsion of Curcumin Stabilized by Cellulose Nanocrystals/Chitosan Oligosaccharide: Effect in Promoting Wound Healing

Background: The stabilization of droplets in Pickering emulsions using solid particles has garnered significant attention through various methods. Cellulose and chitin derivatives in nature offer a sustainable source of Pickering emulsion stabilizers. Methods: In this study, medium-chain triglycerides were used as the oil phase for the preparation of emulsion. This study explores the potential of cellulose nanocrystals (CNC) and shell oligosaccharides (COS) as effective stabilizers for achieving stable Pickering emulsions. Optical microscopy, CLSM, and Cyro-SEM were employed to analyze CNC/COS-Cur, revealing the formation of bright and uniform yellow spherical emulsions. Results: CLSM and SEM results confirmed that CNC/COS formed a continuous and compact shell at the oil-water interface layer, enabling a stable 2~3 microns Pickering emulsion with CNS/COS-Cur as an oil-in-water emulsion stabilizer. Based on FTIR, XRD, and SEM analyses of CNC/COS, along with zeta potential measurements of the emulsion, we found that CNC and COS complexed via electrostatic adsorption, forming irregular rods measuring approximately 200-300 nm in length. An evaluation of the DPPH radical-scavenging ability demonstrated that the CNC/ COS-Cur Pickering emulsion performed well in vitro. In vivo experiments involving full-thickness skin excision surgery in rats revealed that CNC/COS-Cur facilitated wound repair processes. Measurements of the MDA and SOD content in healing tissues indicated that the CNC/COS-Cur Pickering emulsion increased SOD levels and reduced MDA content, effectively countering oxidative stress-induced damage. An assessment based on wound-healing rates and histopathological examination showed that CNC/COS-Cur promoted granulation tissue formation, fibroblast proliferation, angiogenesis, and an accelerated re-epithelialization process within the wound tissue, leading to enhanced collagen deposition and facilitating rapid wound-healing capabilities. An antibacterial efficacy assessment conducted in vitro demonstrated antibacterial activity.

The galactomannan-EGCG physical complex: Effect of branching degree and molecular weight on structural and physiological properties

Polysaccharides and polyphenols are bioactive components that co-exist in many plant foods. Their binary interaction in terms of the structure-function relationships, however, has not been well clarified. This study elucidated the correlation between the structural and physiological properties of galactomannan (GM) -catechin monomer complexes and GM with different branching or molecular weight (Mw). Results indicated that locus bean gum with lower branching degree (Gal/Man is 0.259) bound more readily to EGCG with adsorption rate of 19.42 %. EGCG and ECG containing galloyl groups were more inclined to form hydrogen bonds with GMs, significantly improving the adsorption by GMs. The introduction of EGCG could enhance the antioxidant activity and starch digestion inhibition of GM, which positively correlated with the adsorption capacity of EGCG. The guar gum (GG) with higher Mw (7384.3 kDa) could transport 71.51 % EGCG into the colon, while the retention rate of EGCG reaching the colon alone was only 46.33 %. Conversely, GM-EGCG complex with lower Mw (6.9 kDa) could be readily utilized by gut microbiota, and increased production of short-chain fatty acids (SCFAs). This study elucidated the structure-properties relationship of GM-EGCG complexes, and provide a new idea for the development and precision nutrition of polysaccharides-polyphenol complexes fortified functional foods.

On-Demand Removable Chitosan Based Self-Healing and Antibacterial Hydrogel for Delivery of Tetracycline and Curcumin As Potential Wound Dressing Material

Wound care is a flourishing branch of healthcare wherein a great amount of research is devoted to develop competent wound dressings. Safe, cost-effective, and biocompatible dressings aid in wound healing without inflicting external trauma and subsequent scar formation. Toward this, we have attempted to develop robust wound dressing material with self-healing and antibacterial properties. We have cross-linked chitosan with 4-formyl phenylboronic acid (4-FPBA) and in situ generated dehydroascorbic acid (DHA) utilizing the dynamic imine and boronate ester linkages. Displaying a channeled microstructure in the SEM micrographs, the hydrogel exhibits a massive water uptake capacity of ∼900% at acidic pH. The hydrogel could completely self-heal within 3 min, and the results are further supported by rheological analysis. By virtue of positive surface charge, it shows a promising tissue adhesive property. Moreover, it affords clean and compliant removal from the wound surface via dissolution induced by dopamine to potentially reduce secondary scarring from peeling of wound dressings. The dressing could significantly act against skin infections caused by S. aureus bacteria with enhanced antimicrobial efficiency via loading of antibiotic drug, tetracycline hydrochloride. A sustained release of tetracycline and Curcumin was observed, which demonstrated the release ability for hydrophilic and hydrophobic bioactive agents. In-vitro studies revealed 93% cell viability with a hemolytic ratio as low as 2.5%, thereby presenting a good self-healing and biocompatible material for wound healing.

Lipase-copper complex/chitosan microspheres; loaded with attapulgite used for the treatment of E. coli-induced diarrhea

Diarrhea is a globally major problem especially Escherichia coli induced diarrhea becoming fatal nowadays in developing countries. Colon-targeted chitosan microspheres (Ms) comprising of lipase‑zinc and lipase‑copper complexes were prepared, loaded with Attapulgite (Cts-Li-Zn-ATG/Ms and Cts-Li-Cu-ATG/Ms) for the treatment of bacterial diarrhea. Thin layer chromatography (TLC) and Fourier-transform infrared spectroscopy (FTIR) studies were used for confirmation of proposed lipase-metal complexes. Ms showed particle size range 18 ± 0.24 to 23 ± 0.83 μm, zeta potential -13.7 ± 0.71 to -29.3 ± 1.34 mV, PDI 0.5 ± 0.04 to 1.0 ± 0.07 and hemolytic activity was found to be <5 ± 1.25 %. After coating with Eudragit S-100 for colon targeting, in-vitro % drug release of ATG at pH 7.4 was 80 ± 0.21 % for Eud-Cts-Li-Zn-ATG/Ms while it was increased to 83 ± 0.54 % for Eud-Cts-Li-Cu-ATG/Ms within 7 h, respectively. In-vivo anti-diarrheal activity of Eud-Cts-Li-Zn-ATG/Ms and Eud-Cts-Li-Cu-ATG/Ms was performed by oral challenge on albino mice having infectious diarrhea colonized with E. coli. Results revealed significant anti-diarrheal effect of proposed Eud-Cts-Li-Cu-ATG/Ms in terms of weight gain from 24 ± 0.12 g to 26.05 ± 0.31 g, which was 2-fold increase as compared to Eud-Cts-Li-Zn-ATG/Ms. Conclusively, Eud-Cts-Li-Cu-ATG/Ms provides an innovative alternate for the treatment of bacterial diarrhea with additional support of chitosan and lipase for nutritional support and immunity which was compromised in diarrheal patients.

Insight into divergent chemical modifications of chitosan biopolymer: Review

Chitosan is used in many applications due to its biodegradability, biocompatibility, nontoxicity, nonadhesiveness, and film-forming capabilities. Chitosan has antibacterial and antifungal activities, which are two of its other desirable attributes. However, chitosan can only dissolve in acidic liquids (1-3 % acetic acid), limiting its practical application. The hydroxyl and amino functional groups in the chitosan backbone are essential for chemical modification, which is a viable alternative for overcoming this obstacle. So, N- or O-, and N, O-substituted chitosan may yield derivatives with increased water solubility, biocompatibility, biodegradability, and bio-evaluation. In the same manner, the physicochemical properties of chitosan, including its mechanical and thermal properties, can be improved by cross-linking reactions. This review provides an overview of chitosan, including its origins and their solubility. Also, the review extend and discuss in details most of all chemical reactions that happened on the amino group, hydroxyl group, or both amino group and hydroxyl group to create modified chitosan-based organic materials. Finally, the problems that still need to be solved and probable future areas for study are discussed.

Materials based on biodegradable polymers chitosan/gelatin: a review of potential applications

Increased mass manufacturing and the pervasive use of plastics in many facets of daily life have had detrimental effects on the environment. As a result, these worries heighten the possibility of climate change due to the carbon dioxide emissions from burning conventional, non-biodegradable polymers. Accordingly, biodegradable gelatin and chitosan polymers are being created as a sustainable substitute for non-biodegradable polymeric materials in various applications. Chitosan is the only naturally occurring cationic alkaline polysaccharide, a well-known edible polymer derived from chitin. The biological activities of chitosan, such as its antioxidant, anticancer, and antimicrobial qualities, have recently piqued the interest of researchers. Similarly, gelatin is a naturally occurring polymer derived from the hydrolytic breakdown of collagen protein and offers various medicinal advantages owing to its unique amino acid composition. In this review, we present an overview of recent studies focusing on applying chitosan and gelatin polymers in various fields. These include using gelatin and chitosan as food packaging, antioxidants and antimicrobial properties, properties encapsulating biologically active substances, tissue engineering, microencapsulation technology, water treatment, and drug delivery. This review emphasizes the significance of investigating sustainable options for non-biodegradable plastics. It showcases the diverse uses of gelatin and chitosan polymers in tackling environmental issues and driving progress across different industries.

Silk fibroin biohydrogel composites for loading and ordered release of multiple active ingredients with enhanced bioactivity

Bioactive hydrogels are currently receiving significant attention. In this study, silk fibroin tyramine-modified gelatin hydrogels (SF-TG) with varying degrees of tyramine root substitution were explored. The physicochemical property and biocompatibility of low degree of substitution tyramine-modified gelatin hydrogel (SF-LTG) and high degree of substitution tyramine-modified gelatin hydrogel (SF-HTG) were compared. The results showed that SF-LTG possessed better mechanical property and higher biocompatibility. Thus, SF-LTG was selected as a bioactive matrix and loaded with basic fibroblast growth factor (bFGF); subsequently, curcumin-coupled chitosan rods (CCCRs-EGF) enriched with epidermal growth factor (EGF) were added to obtain SF-LTG-bFGF@CCCRs-EGF hydrogels. The results showed that SF-LTG-bFGF@CCCRs-EGF retained the basic structural and mechanical properties of the SF-LTG matrix gel material and underwent multiple loading and orderly release with different activities while displaying antioxidant, anti-inflammatory, antimicrobial, and pro-cellular proliferation activities and orderly regulation of activity during wound healing. Therefore, the SF-LTG-bFGF@CCCRs-EGF hydrogel is of great value in healing complex wounds.

Covalent modification of γ-cyclodextrin with geraniol: An antibacterial agent with good thermal stability, solubility and biocompatibility

Geraniol (Ger) is an essential oil molecule with excellent biological activity. High hydrophobicity and volatility limit its practical application. Cyclodextrins (CDs) are water-soluble cyclic oligosaccharides with hydrophobic cavities. Physical encapsulation of CDs to improve the solubility and stability of essential oil molecules is not satisfactory. Therefore, this study synthesized the γ-CD derivative (γ-CD-Ger) by grafting Ger onto γ-CD using a bromide-mediated method. Compared to the inclusion complexes (γ-CD/Ger) formed by both, the derivatives exhibit better solubility and thermal stability. The derivative has better antibacterial activity when the ratio of γ-CD to Ger was 1:2. In addition, the derivatives did not exhibit cytotoxic and hemolytic properties. These results indicate that this research provides a water-soluble antibacterial agent with a wide range of promising applications and offers new ideas for the application of alcohol hydrophobic molecules in aqueous systems.

Technological Interventions Enhancing Curcumin Bioavailability in Wound-Healing Therapeutics

Wound healing has been a challenge in the medical field. Tremendous research has been carried out to expedite wound healing by fabricating various formulations, some of which are now commercially available. However, owing to their natural source, people have been attracted to advanced formulations with herbal components. Among various herbs, curcumin has been the center of attraction from ancient times for its healing properties due to its multiple therapeutic effects, including antioxidant, antimicrobial, anti-inflammatory, anticarcinogenic, neuroprotective, and radioprotective properties. However, curcumin has a low water solubility and rapidly degrades into inactive metabolites, which limits its therapeutic efficacy. Henceforth, a carrier system is needed to carry curcumin, guard it against degradation, and keep its bioavailability and effectiveness. Different formulations with curcumin have been synthesized, and exist in the form of various synthetic and natural materials, including nanoparticles, hydrogels, scaffolds, films, fibers, and nanoemulgels, improving its bioavailability dramatically. This review discusses the advances in different types of curcumin-based formulations used in wound healing in recent times, concentrating on its mechanisms of action and discussing the updates on its application at several stages of the wound healing process. Impact statement Curcumin is a herbal compound extracted from turmeric root and has been used since time immemorial for its health benefits including wound healing. In clinical formulations, curcumin shows low bioavailability, which mainly stems from the way it is delivered in the body. Henceforth, a carrier system is needed to carry curcumin, guard it against degradation, while maintaining its bioavailability and therapeutic efficacy. This review offers an overview of the advanced technological interventions through tissue engineering approaches to efficiently utilize curcumin in different types of wound healing applications.

Microbial fermentation-based synthesis of nano-curcumin suggesting the role of pullulan in nano-formulation

Curcumin is a multitargeting nutraceutical with numerous health benefits, however, its efficacy is limited due to poor aqueous solubility and reduced bioavailability. While nano-formulation has emerged as an alternative to encounter such issues, it often involves use of toxic solvents. Microbial synthesis may be an innovative solution to address this lacuna. Present study, for the first time, reports exploitation of Aureobasidium pullulans RBF4A3 for production of nano-curcumin. For this purpose, Aureobasidium pullulans RBF4A3 was inoculated in YPD media along with curcumin (0.1 mg/mL) and incubated for 24 h, 48 h, and 72 h. Subsequently, residual sugar, biomass, EPS concentration, curcumin concentration, and curcumin nanoparticle size were measured. As a result, nano-curcumin with an average particle size of 31.63 nm and enhanced aqueous solubility was obtained after 72 h. Further, investigations suggested that pullulan, a reducing polysaccharide, played a significant role in curcumin nano-formulation. Pullulan-mediated nano-curcumin formulation, with an average particle size of 24 nm was achieved with conversion rate of around 59.19 %, suggesting improved aqueous solubility. Additionally, the anti-oxidant assay of the resulting nano-curcumin was around 53.7 % per μg. Moreover, kinetics and thermodynamic studies of pullulan-based nano-curcumin revealed that it followed first-order kinetics and was favored by elevated temperature for efficient bio-conversion. Also, various physico-chemical investigations like FT-IR, NMR, and XRD reveal that pullulan backbone remains intact while forming curcumin nanoparticle. This study may open up new avenues for synthesizing nano-polyphenols through a completely green and solvent free process with plausible diverse applications.

Enhancing the therapeutic potential of curcumin: a novel nanoformulation for targeted anticancer therapy to colorectal cancer with reduced miR20a and miR21 expression

Curcumin (Cur) possesses remarkable pharmacological properties, including cardioprotective, neuroprotective, antimicrobial, and anticancer activities. However, the utilization of Cur in pharmaceuticals faces constraints owing to its inadequate water solubility and limited bioavailability. To overcome these hurdles, there has been notable focus on exploring innovative formulations, with nanobiotechnology emerging as a promising avenue to enhance the therapeutic effectiveness of these complex compounds. We report a novel safe, effective method for improving the incorporation of anticancer curcumin to induce apoptosis by reducing the expression levels of miR20a and miR21. The established method features three aspects that, to our knowledge, have not been formally verified: (1) use of a novel formula to incorporate curcumin, (2) use of all biocompatible biodegradable materials to produce this formula without leaving harmful residues, and (3) an incorporation process at temperatures of approximately 50 °C. The formula was prepared from lecithin (LE), and chitosan (CH) with an eco-friendly emulsifying agent and olive oil as the curcumin solvent. The formula was converted to nanoscale through ultrasonication and probe sonication at a frequency of 20 kHz. Transmission electron microscopy showed that the nano formula was spherical in shape with sizes ranging between 49.7 nm in diameter and negative zeta potentials ranging from 28 to 34 mV. Primers miR20a and miR21 were designed for molecular studies. Nearly complete curcumin with an encapsulation efficiency of 91.1% was established using a straight-line equation. The nano formula incorporated with curcumin was used to prepare formulations that exhibited anticancer activities. The apoptosis pathway in cancer cells was activated by the minimum inhibitory concentration of the nano formula. These findings suggest the potential of this nanoformulation as an effective and selective cancer treatment that does not affect the normal cells.

Exploring the Prospective of Curcumin-loaded Nanomedicine in Brain Cancer Therapy: An Overview of Recent Updates and Patented Nanoformulations

Cancer is a complex, one of the fatal non-communicable diseases, and its treatment has enormous challenges, with variable efficacy of traditional anti-cancer agents. By 2025, it is expected that 420 million additional cases of cancer will be diagnosed yearly. However, among various types of cancer, brain cancer treatment is most difficult due to the presence of blood-brain barriers. Nowadays, phytoconstituents are gaining popularity because of their biosafety and low toxicity to healthy cells. This article reviews various aspects related to curcumin for brain cancer therapeutics, including epidemiology, the role of nanotechnology, and various challenges for development and clinical trials. Furthermore, it elaborates on the prospects of curcumin for brain cancer therapeutics. In this article, our objective is to illuminate the anti-cancer potential of curcumin for brain cancer therapy. Moreover, it also explores how to defeat its constraints of clinical application because of poor bioavailability, stability, and rapid metabolism. This review also emphasizes the possibility of curcumin for the cure of brain cancer using cuttingedge biotechnological methods based on nanomedicine. This review further highlights the recent patents on curcumin-loaded nanoformulations for brain cancer. Overall, this article provides an overview of curcumin's potential in brain cancer therapy by considering challenges to be overwhelmed and future prospective. Moreover, this review summarizes the reported literature on the latest research related to the utility of curcumin in brain cancer therapy and aims to provide a reference for advanced investigation on brain cancer treatment.

In situ forming alginate/gelatin hydrogel scaffold through Schiff base reaction embedded with curcumin-loaded chitosan microspheres for bone tissue regeneration

In this study, we developed a biocompatible composite hydrogel that incorporates microspheres. This was achieved using a Schiff base reaction, which combines the amino and aldehyde groups present in gelatin (Gel) and oxidized alginate (OAlg). We suggest this hydrogel as a promising scaffold for bone tissue regeneration. To further boost its osteogenic capabilities and mechanical resilience, we synthesized curcumin (Cur)-loaded chitosan microspheres (CMs) and integrated them into the Gel-OAlg matrix. This formed a robust composite gel framework. We conducted comprehensive evaluations of various properties, including gelation time, morphology, compressive strength, rheological behavior, texture, swelling rate, in vitro degradation, and release patterns. A remarkable observation was that the inclusion of 30 mg/mL Cur-CMs significantly enhanced the hydrogel's mechanical and bioactive features. Over three weeks, the Gel-OAlg/Cur-CMs (30) composite showed a cumulative curcumin release of 35.57%. This was notably lower than that observed in standalone CMs and Gel-OAlg hydrogels. Additionally, the Gel-OAlg/Cur-CMs (30) hydrogel presented a reduced swelling rate and weight loss relative to hydrogels devoid of Cur-CMs. On the cellular front, the Gel-OAlg/Cur-CMs (30) hydrogel showcased superior biocompatibility. It also displayed increased calcium deposition, alkaline phosphatase (ALP) activity, and elevated osteogenic gene expression in human bone marrow mesenchymal stem cells (hBMSCs). These results solidify its potential as a scaffold for bone tissue regeneration.

Therapeutic applications of sustainable new chitosan derivatives and its nanocomposites: Fabrication and characterization

Chitosan (CS) is a biologically active biopolymer used in different medical applications due to its biodegradability, biocompatibility, and nontoxicity. Nanotechnology is an exciting and quick developing field in medical applications. Nanoparticles have shown great potential in the treatment of cancer and inflammation. In the present work modification of chitosan and its (Ag, Au, or ZnO) nanocomposites by N-aminophthalimide (NAP) occurred through the reaction with epichlorohydrin (ECH) as a crosslinker in the presence or absence of glutaraldehyde (GA) under different reaction conditions using microwave irradiation to give modified chitosan derivatives CS-2, CS-6, and their nanocomposites. Modified chitosan derivatives were characterized using different tools. CS-2 and CS-6 derivatives displayed enhancement of thermal stability and crystallinity compared to chitosan. Additionally, CS-2, CS-6, and their nanocomposites exhibited improvements in antitumor activity against HeLa cancer cells and enzymatic inhibitory against trypsin and α-chymotrypsin enzymes compared to chitosan. However, CS-2 revealed the highest cell growth inhibition% toward HeLa cells (89.02 ± 1.46 %) and the enzymatic inhibitory toward α-chymotrypsin enzyme (17.13 ± 1.59 %). Furthermore, CS-Au-2 showed the highest enzymatic inhibitory against trypsin enzyme (28.14 ± 1.76 %). These results suggested that the new chitosan derivatives CS-2, CS-6, and their nanocomposites could be a platform for medical applications against HeLa cells, trypsin, and α-chymotrypsin enzymes.

Encapsulation in Oxygen-Loaded Nanobubbles Enhances the Antimicrobial Effectiveness of Photoactivated Curcumin

In both healthcare and agriculture, antibiotic resistance is an alarming issue. Biocompatible and biodegradable ingredients (e.g., curcumin) are given priority in "green" criteria supported by the Next Generation EU platform. The solubility and stability of curcumin would be significantly improved if it were enclosed in nanobubbles (NB), and photoactivation with the correct wavelength of light can increase its antibacterial efficacy. A continuous release of curcumin over a prolonged period was provided by using innovative chitosan-shelled carriers, i.e., curcumin-containing nanobubbles (Curc-CS-NBs) and oxygen-loaded curcumin-containing nanobubbles (Curc-Oxy-CS-NBs). The results demonstrated that after photoactivation, both types of NBs exhibited increased effectiveness. For Staphylococcus aureus, the minimum inhibitory concentration (MIC) for Curc-CS-NBs remained at 46 µg/mL following photodynamic activation, whereas it drastically dropped to 12 µg/mL for Curc-Oxy-CS-NBs. Enterococcus faecalis shows a decreased MIC for Curc-CS-NB and Curc-Oxy-CS-NB (23 and 46 µg/mL, respectively). All bacterial strains were more effectively killed by NBs that had both oxygen and LED irradiation. A combination of Curc-Oxy-CS-NB and photodynamic stimulation led to a killing of microorganisms due to ROS-induced bacterial membrane leakage. This approach was particularly effective against Escherichia coli. In conclusion, this work shows that Curc-CS-NBs and Curc-Oxy-CS-exhibit extremely powerful antibacterial properties and represent a potential strategy to prevent antibiotic resistance and encourage the use of eco-friendly substitutes in agriculture and healthcare.

Curcumin-Sodium Alginate and Curcumin-Chitosan Conjugates as Drug Delivery Systems: An Interesting Rheological Behaviour

The conjugation of polyphenols is a valuable strategy with which to confer tailored properties to polymeric materials of biomedical interest. Within this investigation, we aim to explore the possibility to use this synthetic approach to increase the viscosity of conjugates, thus allowing the release of a loaded therapeutic to be better controlled over time than in neat polyphenols. Curcumin (CUR) was conjugated to sodium alginate (CA) and chitosan (CS) with functionalisation degrees of 9.2 (SA-CUR) and 15.4 (CS-CUR) mg g-1. Calorimetric analyses showed higher degrees of chain rigidity upon conjugation, with a shift of the degradation peaks to higher temperatures (from 239 to 245 °C and from 296 to 303 °C for SA-CUR and CS-CUR, respectively). Rheological analyses were used to prove the enhanced interconnection between the polymer chains in the conjugates, confirmed by the weak gel parameters, A and z. Moreover, the typical non-Newtonian behaviour of the high-molecular-weight polysaccharides was recorded, together with an enhancement of the activation energy, Ea, in CS-CUR vs. CS (opposite behaviour recorded for SA-CUR vs. SA). The evaluation of the delivery performance (of Doxorubicin as a model drug) showed sustained release profiles, opening opportunities for the development of controlled delivery systems.

Chitosan: A Potential Biopolymer in Drug Delivery and Biomedical Applications

Chitosan, a biocompatible and biodegradable polysaccharide derived from chitin, has surfaced as a material of promise for drug delivery and biomedical applications. Different chitin and chitosan extraction techniques can produce materials with unique properties, which can be further modified to enhance their bioactivities. Chitosan-based drug delivery systems have been developed for various routes of administration, including oral, ophthalmic, transdermal, nasal, and vaginal, allowing for targeted and sustained release of drugs. Additionally, chitosan has been used in numerous biomedical applications, such as bone regeneration, cartilage tissue regeneration, cardiac tissue regeneration, corneal regeneration, periodontal tissue regeneration, and wound healing. Moreover, chitosan has also been utilized in gene delivery, bioimaging, vaccination, and cosmeceutical applications. Modified chitosan derivatives have been developed to improve their biocompatibility and enhance their properties, resulting in innovative materials with promising potentials in various biomedical applications. This article summarizes the recent findings on chitosan and its application in drug delivery and biomedical science.

Synthesis of chitosan succinate-g-amine functionalized mesoporous silica: Inorganic-organic nanohybrid for antibacterial assessment, antioxidant activity and pH-controlled drug delivery

An innovative and proficient inorganic-organic nanohybrid was synthesized by using amine modified MCM-41 as an inorganic precursor combined with organic moiety, a derivative of chitosan i.e. chitosan succinate through amide bond. These nanohybrids can be used in diverse applications due to potential combination of desired properties of inorganic and organic components. The nanohybrid was characterized by FTIR, TGA, small angle powder XRD, zeta potential, particle size distribution, BET, proton NMR and ¹³C NMR techniques to confirm its formation. The synthesized hybrid was loaded with curcumin drug to check its potential application for controlled drug release, showing 80 % drug release in acidic medium (i.e. pH -5.0), while physiological pH -7.4 shows only 25 % release. The encapsulation efficiency of nanohybrid is 87.24 %. The results of antibacterial performances are demonstrated in terms of ZOI (zone of inhibition) which depicts that hybrid material shows better ZOI in gram negative (E. coli) than for gram positive (B. subtilis) bacteria. Nanohybrid was also tested for the antioxidant activity by using two different methods (DPPH and ABTS) radical scavenging methods. The ability of nano-hybrid to scavenge DPPH radicals was found 65 %, and ability to scavenge ABTS radicals was 62.47 %.

Functionalization of chitosan with poly aromatic hydroxyl molecules for improving its antibacterial and antioxidant properties: Practical and theoretical studies

In this study, the chitosan backbone was functionalized with 2,2',4,4'-tetrahydroxybenzophenone by Schiff base, bonding the molecules into the repeating amine groups. The use of ¹H NMR, FT-IR, and UV-Vis analyses provided compelling evidence of the structure of the newly developed derivatives. The deacetylation degree was calculated to be 75.35 %, and the degree of substitution was 5.53 % according to elemental analysis. The thermal analysis of samples using TGA demonstrated that CS-THB derivatives are more stable than chitosan itself. SEM was used to investigate the change in surface morphology. The improvement of the biological properties of chitosan was investigated in terms of its antibacterial activity against pathogenic antibiotic-resistant bacteria. The antioxidant properties showed an improvement in activity compared to chitosan by two times against ABTS radicals and four times against DPPH radicals. Furthermore, the cytotoxicity and anti-inflammatory properties were investigated using normal skin cells (HBF4) and WBCs. Quantum chemistry calculations revealed that combining polyphenol with chitosan makes it more effective as an antioxidant than either chitosan or polyphenol alone. Our findings suggest that the new chitosan Schiff base derivative could be utilized for tissue regeneration applications.

Preparation and characterization of curcumin/chitosan conjugate as an efficient photodynamic antibacterial agent

Curcumin (Cur) is a natural pigment with excellent biological activity. The poor stability and insolubility of Cur in water severely limit its application. Therefore, to overcome these dilemmas which are big hindrances in their application, a novel derivative (COCS-Cur) was prepared by the esterification reaction of carboxylated chitosan (COCS) and Cur. The structure and properties of conjugate were determined through a series of characterizations. The derivatives had excellent solubility as well as stability. In addition, antioxidant and photodynamic antibacterial experiments proved that COCS-Cur had the excellent free radical scavenging ability and photodynamic antibacterial activity. The derivatives presented a better antibacterial effect on Staphylococcus aureus (S. aureus) than Escherichia coli (E. coli). Noteworthy, the COCS-Cur derivatives showed no obvious toxicity which makes them a stronger contender and potential antimicrobial agent or functional nutrient for application in the food industry.

Studies on anti-colon cancer potential of nanoformulations of curcumin and succinylated curcumin in mannosylated chitosan

Colon cancer (CRC) is the second leading cause of death and the third most diagnosed cancer worldwide. Although curcumin (CUR) has demonstrated a potent anticancer activity, it is characterized by its poor solubility, low bioavailability, and instability. This study is a projection from a previous investigation where CUR and succinylated CUR (CUR.SA) were separately encapsulated in mannosylated-chitosan nanoparticles (CM-NPs) to form CUR-NPs and CUR.SA-NPs, respectively. Here, we aim to assess the anti-CRC activity of these two nanoformulations. Cytotoxicity studies using CCK-8 assay indicated that both CUR-NPs and CUR.SA-NPs have a dose and time-dependent toxicity towards CRC human cell-lines (HCT116 and SW480), and more cytotoxic compared to free CUR or CUR-SA in a time-dependent manner. A significant induction of early and late apoptosis in the CUR-NPs and CUR.SA-NPs treated CRC cell lines compared to untreated cells was observed. Western blotting analyses confirmed the induction of apoptosis through activation of Caspase signaling compared to untreated cells. Based on the physicochemical properties of CUR-NPs and CUR.SA-NPs along with the data from the in vitro studies, we may conclude these nanoparticle formulations hold very promising attributes, worthy of further investigations for its role in the management of CRC.

Current and future outlook of loaded components in hydrogel composites for the treatment of chronic diabetic ulcers

Due to recalcitrant microangiopathy and chronic infection, traditional treatments do not easily produce satisfactory results for chronic diabetic ulcers. In recent years, due to the advantages of high biocompatibility and modifiability, an increasing number of hydrogel materials have been applied to the treatment of chronic wounds in diabetic patients. Research on composite hydrogels has received increasing attention since loading different components can greatly increase the ability of composite hydrogels to treat chronic diabetic wounds. This review summarizes and details a variety of newly loaded components currently used in hydrogel composites for the treatment of chronic diabetic ulcers, such as polymer/polysaccharides/organic chemicals, stem cells/exosomes/progenitor cells, chelating agents/metal ions, plant extracts, proteins (cytokines/peptides/enzymes) and nucleoside products, and medicines/drugs, to help researchers understand the characteristics of these components in the treatment of diabetic chronic wounds. This review also discusses a number of components that have not yet been applied but have the potential to be loaded into hydrogels, all of which play roles in the biomedical field and may become important loading components in the future. This review provides a "loading component shelf" for researchers of composite hydrogels and a theoretical basis for the future construction of "all-in-one" hydrogels.

The Progress of Chitosan-Based Nanoparticles for Intravesical Bladder Cancer Treatment

Bladder cancer (BC) is the most frequently occurring cancer of the urinary system, with non-muscle-invasive bladder cancer (NMIBC) accounting for 75-85% of all the bladder cancers. Patients with NMIBC have a good survival rate but are at high risk for tumor recurrence and disease progression. Intravesical instillation of antitumor agents is the standard treatment for NMIBC following transurethral resection of bladder tumors. Chemotherapeutic drugs are broadly employed for bladder cancer treatment, but have limited efficacy due to chemo-resistance and systemic toxicity. Additionally, the periodic voiding of bladder and low permeability of the bladder urothelium impair the retention of drugs, resulting in a weak antitumoral response. Chitosan is a non-toxic and biocompatible polymer which enables better penetration of specific drugs to the deeper cell layers of the bladder as a consequence of temporarily abolishing the barrier function of urothelium, thus offering multifaceted biomedical applications in urinary bladder epithelial. Nowadays, the rapid development of nanoparticles significantly improves the tumor therapy with enhanced drug transport. This review presents an overview on the state of chitosan-based nanoparticles in the field of intravesical bladder cancer treatment.

Antibacterial and antibiofilm activity of mannose-modified chitosan/PMLA nanoparticles against multidrug-resistant Helicobacter pylori

Because of the apparent stasis in antibiotic discoveries and the growth of multidrug resistance, Helicobacter pylori-associated gastric infections are difficult to eradicate. In the search for alternative therapy, the reductive amination of chitosan with mannose, followed by ionic gelation, produced mannose functionalized chitosan nanoparticles. Then, molecular docking and molecular dynamics (MD) simulations were conducted with H. pylori lectin (HPLectin) as a target protein involved in bacterium adherence to host cells, biofilm formation, and cytotoxicity. Changes in zeta potential and FTIR spectroscopy revealed that chitosan was functionalized with mannose. Time-kill, polystyrene adherence, and antibiofilm studies were utilized to assess nanoparticles as an alternative antibacterial treatment against a resistant gastric pathogen. Man-CS-Nps were discovered to have effective anti-adherence and biofilm disruption characteristics in suppressing the development of resistant H. pylori. In addition, bioimaging studies with CLSM, TEM, and SEM illustrated that Man-CS-Nps interacted with bacterial cells and induced membrane disruption by creating holes in the outer membranes of the bacterial cells, resulting in the leakage of amino acids. Importantly, molecular docking and 20 ns MD simulations revealed that Man-CS-Nps inhibited the target protein through slow-binding inhibition and hydrogen bond interactions with active site residues. As a consequence of the findings of this study, the Man-CS-Nps is an excellent candidate for developing alternative therapies for the increasing incidences of resistant gastric infections.

The Potential of Curcumin-Capped Nanoparticle Synthesis in Cancer Therapy: A Green Synthesis Approach

Cancer nanotherapeutics is an important field of research which utilizes nanomaterials as an approach to cancer therapy. Nano-mediated therapeutic delivery systems overcome the adverse side effects of traditional cancer treatment methods. Nanoparticles (NPs) are considered excellent tumor-targeting vehicles due to their compact and variable size, large surface area, ability to load several genes and drugs, and mediation of increased therapeutic payload uptake. Despite the rapid development of nanotechnology, there is growing concern regarding the possible long-term side effects of NPs on the environment and human health. Green chemistry using plant materials, such as curcumin, is a sustainable alternative to conventional reduction methods and confers dual reducing and capping properties. Curcumin is a bioactive compound isolated from the rhizome of the Curcuma longa plant, which exhibits various medicinal properties. Curcumin-capped NPs exhibit increased solubility, bioavailability, therapeutic indices, and antitumor properties. This review highlights the potential and antitumor properties of economical, simple, and eco-friendly curcumin-synthesized and capped NPs for the localized delivery of therapeutic genes and drugs to the cancer tumor microenvironment with fewer adverse side effects.

Recent development in nanoencapsulation and delivery of natural bioactives through chitosan scaffolds for various biological applications

Nowadays, nano/micro-encapsulation as a pioneering technique may significantly improve the bioavailability and durability of Natural bioactives. For this purpose, chitosan as a bioactive cationic natural polysaccharide has been frequently used as a carrier because of its distinct chemical and biological properties, including polycationic nature, biocompatibility, and biodegradability. Moreover, polysaccharide-based nano/micro-formulations are a new and extensive trend in scientific research and development in the disciplines of biomedicine, bioorganic/ medicinal chemistry, pharmaceutics, agrochemistry, and the food industry. It promises a new paradigm in drug delivery systems and nanocarrier formulations. This review aims to summarize current developments in approaches for designing innovative chitosan micro/nano-matrix, with an emphasis on the encapsulation of natural bioactives. The special emphasis led to a detailed integrative scientific achievement of the functionalities and abilities for encapsulating natural bioactives and mechanisms regulated in vitro/in vivo release in various biological/physiological environments.

3-Formylindole-based chitosan Schiff base polymer: Antioxidant and in vitro cytotoxicity studies on THP-1 cells

Two imine derivatives of chitosan (i-CTs), namely 2FCT and 5MCT, were synthesized by reacting chitosan (CT) with 2-(3-formyl-1H-indol-1yl)acetonitrile (2F), and 5-methoxyindole-3-carbaldehyde (5M), respectively. The antimicrobial evaluation of i-CTs exhibited stronger inhibition effect against Staphylococcus aureus, Escherichia coli and Candida albicans. The antioxidant activity of 2FCT and 5MCT showed strong scavenging ability with IC₅₀ 2.31 and 6.92 μg/mL, respectively. The results of in vitro cytotoxicity of 2FCT and 5MCT examined using human monocyte leukemia (THP-1) cells indicate no cytotoxic effect on host cells and the value of cell viability was found to be 87.08 and 84.47%, respectively. Measurement of intracellular Reactive Oxygen Species (ROS) production by flow cytometry analysis revealed that the 2FCT and 5MCT reduced the ROS generation by 83 and 43%, respectively. In summary, these findings show that i-CTs synthesized to be promising biomaterial for biomedical applications such as wound healing.

Curcumin and Derivatives in Nanoformulations with Therapeutic Potential on Colorectal Cancer

There is growing concern in the rise of colorectal cancer (CRC) cases globally, and with this rise is the presentation of drug resistance. Like other cancers, current treatment options are either invasive or manifest severe side effects. Thus, there is a move towards implementing safer treatment options. Curcumin (CUR), extracted from Curcuma longa, has received significant attention by scientists as possible alternative to chemotherapeutic agents. It is safe and effective against CRC and nontoxic in moderate concentrations. Crucially, it specifically modulates apoptotic effects on CRC. However, the use of CUR is limited by its low solubility and poor bioavailability in aqueous media. These limitations are surmountable through novel approaches, such as nanoencapsulation of CUR, which masks the physicochemical properties of CUR, thus potentiating its anti-CRC effects. Furthermore, chemical derivatization of CUR is another approach that can be used to address the above constraints. This review spans published work in the last two decades, with key findings employing either of the two approaches, in addition to a combined approach in managing CRC. The combined approach affords the possibility of better treatment outcomes but not widely investigated nor yet clinically implemented.

Chitosan-curcumin complexation to develop functionalized nanosystems with enhanced antimicrobial activity against hetero-resistant gastric pathogen

With the apparent stagnation in the antibiotic discovery and the propagation of multidrug resistance, Helicobacter pylori associated gastric infections are hard to eradicate. In pursuance of alternative medicines, in this study, covalent modification of chitosan (CS) polymer with curcumin (Cur) was accomplished. Proton Nuclear Magnetic Resonance and Fourier Transform Infrared spectroscopy elucidated the covalent interaction between Cur and CS with characteristic peak of imine functional group (C=N). Scanning Electron Microscopy provided visual proof for surface topology, while size and zeta potential values further affirmed the development of curcumin functionalized chitosan nanosystems (Cur-FCNS). The complexation efficiency of CS with Cur was found as 70 ± 3% at an optimal ratio of 5:1 for CS and Cur, respectively. Cur-FCNS developed with ionic gelation and ultrasonication method demonstrated synergistic anti-H. pylori activity in growth-kinetics and anti-biofilm assays, which was superior to free Cur and even chitosan nanosystems. Under simulated gastric conditions, Cur-FCNS revealed cumulative-release of only 16 ± 0.8% till 40 h, which indicated its improved stability to interact with H. pylori. In silico findings affirmed high binding affinity of Cur-FCNS with multiple bacterial virulence factors. Thus, our results affirmed the exceptional potential of Cur-FCNS as next-generation alternative-medicine to treat resistant H. pylori.

Synthesis and in vitro evaluation of natural drug loaded polymeric films for cardiovascular applications

Drug eluting stents (DES) can efficiently reduce the atherosclerosis and restenosis issues of coronary artery as compared to bare metal stents due to the presence of pharmaceutically active agent on their surface. Nevertheless, the arising safety concerns of DES such as delayed healing and late in stent restenosis and thrombus, has stirred the research efforts to improve the outcomes of the DES. In this connection, attention is being shifted from the use of synthetic drug to natural drug for DES. In the present work, natural compound loaded polymeric films were synthesized and their antioxidant and anticoagulation capabilities were assessed through in vitro testing. The potential of the drug loaded polymeric films to curb the production of free radicals was evaluated by carrying out antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The in vitro platelet adhesion was investigated through static platelet adhesion test while effect of synthesized films on intrinsic coagulation pathway was investigated through activated partially thromboplastin time (APTT). Moreover, to further evaluate the blood compatibility of the developed drug loaded films, in vitro hemolytic and anti-thrombolytic assays were carried out. The obtained results indicated that, incorporating herbal compounds such as ginger, magnolol and curcumin, in polymeric matrix (PVA) has significantly improved the blood compatibility of the polymeric films. Hence, it can be concluded that the synthesized drug loaded polymeric films have the potential capability to be used as a potential coating material for coating biomedical implants with good anticoagulation and antioxidant property to cater the cardiovascular issues such as atherosclerosis, restenosis and thrombus formation.

Polysaccharide-Drug Conjugates: A Tool for Enhanced Cancer Therapy

Cancer is one of the most widespread deadly diseases, following cardiovascular disease, worldwide. Chemotherapy is widely used in combination with surgery, hormone and radiation therapy to treat various cancers. However, chemotherapeutic drugs can cause severe side effects due to non-specific targeting, poor bioavailability, low therapeutic indices, and high dose requirements. Several drug carriers successfully overcome these issues and deliver drugs to the desired sites, reducing the side effects. Among various drug delivery systems, polysaccharide-based carriers that target only the cancer cells have been developed to overcome the toxicity of chemotherapeutics. Polysaccharides are non-toxic, biodegradable, hydrophilic biopolymers that can be easily modified chemically to improve the bioavailability and stability for delivering therapeutics into cancer tissues. Different polysaccharides, such as chitosan, alginates, cyclodextrin, pullulan, hyaluronic acid, dextran, guar gum, pectin, and cellulose, have been used in anti-cancer drug delivery systems. This review highlights the recent progress made in polysaccharides-based drug carriers in anti-cancer therapy.

Polyphenol-Polysaccharide Complex: Preparation, Characterization and Potential Utilization in Food and Health

Polysaccharides and polyphenols coexist in many plant-based food products. Polyphenol-polysaccharide interactions may affect the physicochemical, functional, and physiological properties, such as digestibility, bioavailability, and stability, of plant-based foods. In this review, the interactions (physically or covalently linked) between the selected polysaccharides and polyphenols are summarized. The preparation and structural characterization of the polyphenol-polysaccharide conjugates, their structural-interaction relationships, and the effects of the interactions on functional and physiological properties of the polyphenol and polysaccharide molecules are reviewed. Moreover, potential applications of polyphenol-polysaccharide conjugates are discussed. This review aids in a comprehensive understanding of the synthetic strategy, beneficial bioactivity, and potential application of polyphenol-polysaccharide complexes. Expected final online publication date for the Annual Review of Food Science and Technology, Volume 13 is March 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

The Expanded Role of Chitosan in Localized Antimicrobial Therapy

Chitosan is one of the most studied natural origin polymers for biomedical applications. This review focuses on the potential of chitosan in localized antimicrobial therapy to address the challenges of current rising antimicrobial resistance. Due to its mucoadhesiveness, chitosan offers the opportunity to prolong the formulation residence time at mucosal sites; its wound healing properties open possibilities to utilize chitosan as wound dressings with multitargeted activities and more. We provide an unbiased overview of the state-of-the-art chitosan-based delivery systems categorized by the administration site, addressing the site-related challenges and evaluating the representative formulations. Specifically, we offer an in-depth analysis of the current challenges of the chitosan-based novel delivery systems for skin and vaginal infections, including its formulations optimizations and limitations. A brief overview of chitosan's potential in treating ocular, buccal and dental, and nasal infections is included. We close the review with remarks on toxicity issues and remaining challenges and perspectives.

Design and synthesis of curcumin nanostructures: Evaluation of solubility, stability, antibacterial and antioxidant activities

By coupling a quaternary pyridinium compound and curcumin (CM), a new antimicrobial agent called CP was obtained. The poor water-solubility was the most important limiting factor in the use of CM and CP. To address this problem, a hydrophilic hyperbranched polyglycerol (PG) was synthesized and reacted with CM and CP via Schiff base reaction to form two new macromolecules. Due to the presence of polymer, the solubility and stability of CM and CP increased significantly in aqueous media. Since the new macromolecules were including the hydrophilic polymeric and curcumin hydrophobic units, they self-assembled into spherical nanostructures, which were characterized by Field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) images. The synthetic nanostructures exhibited a controlled release of curcumin unit in the acidic environment. In vitro experiments showed that the new macromolecules are potent antibacterial and antioxidant agents.

Antimicrobial Activity of Curcumin in Nanoformulations: A Comprehensive Review

Curcumin (CUR) is a natural substance extracted from turmeric that has antimicrobial properties. Due to its ability to absorb light in the blue spectrum, CUR is also used as a photosensitizer (PS) in antimicrobial Photodynamic Therapy (aPDT). However, CUR is hydrophobic, unstable in solutions, and has low bioavailability, which hinders its clinical use. To circumvent these drawbacks, drug delivery systems (DDSs) have been used. In this review, we summarize the DDSs used to carry CUR and their antimicrobial effect against viruses, bacteria, and fungi, including drug-resistant strains and emergent pathogens such as SARS-CoV-2. The reviewed DDSs include colloidal (micelles, liposomes, nanoemulsions, cyclodextrins, chitosan, and other polymeric nanoparticles), metallic, and mesoporous particles, as well as graphene, quantum dots, and hybrid nanosystems such as films and hydrogels. Free (non-encapsulated) CUR and CUR loaded in DDSs have a broad-spectrum antimicrobial action when used alone or as a PS in aPDT. They also show low cytotoxicity, in vivo biocompatibility, and improved wound healing. Although there are several in vitro and some in vivo investigations describing the nanotechnological aspects and the potential antimicrobial application of CUR-loaded DDSs, clinical trials are not reported and further studies should translate this evidence to the clinical scenarios of infections.

Optimization by Central Composite Experimental Design of the Synthesis of Physically Crosslinked Chitosan Spheres

Chitosan (CS) has special properties such as biocompatibility, biodegradability, antibacterial, and biological activity which make this material is currently studied in various applications, including tissue engineering. There are different methods to modify the morphology of CS. Most use chemical crosslinking agents, however, those methods have disadvantages such as low polymer degradability and unwanted side effects. The objective of this research was to obtain CS spheres through the physical crosslinking of commercial CS without using crosslinking agents through a simple coacervation method. A central composite experimental design was used to optimize the synthesis of the CS spheres and by the response surface methodology it was possible to obtain CS spheres with the smallest diameter and the most regular morphology. With the optimal formulation (CS solution 1.8% (w/v), acetic acid (AAC) solution 1% (w/v), sodium hydroxide (NaOH) solution 13% (w/v), relative humidity of (10%) and needle diameter of 0.6 mm), a final sphere diameter of 1 mm was obtained. Spheres were characterized by physical, chemical, thermal, and biological properties in simulated body fluid (SBF). The results obtained allowed us to understand the effect of the studied variables on the spheres' diameter. An optimized condition facilitated the change in the morphology of the CS while maintaining its desirable properties for use in tissue engineering.