Influence of the graft density of hydrophobic groups on thermo-responsive nanoparticles for anti-cancer drugs delivery

Thermo-responsive composite nanoparticles based on hydroxybutyl chitosan oligosaccharide: Fabrication, stimulus release and cancer therapy

Designing thermo-responsive nanocarriers based on biopolymers is fascinating and challenging for cancer therapy. In this study, thermo-responsive composite nanoparticles (CNPs) were prepared using hydroxybutyl chitosan oligosaccharide (HBCOS) and sodium caseinate (SC) via electrostatic interactions and covalent crosslinking. The temperature-responsive behaviors of CNPs were induced by the breakage of hydrogen bonds and the shrinkage of chains in nanoparticles. The CNPs exhibited concentration-independent thermo-responsive behavior, non-adsorption aggregation, and non-hemolysis, suggesting excellent stability and thermo-sensitivity. The initial release rate and final amount of DOX released from CNPs at 42 °C were higher than that at 37 °C, showing a thermo-responsive release, which was also more prominent at lower pH. The release of DOX from CNPs followed first order kinetics based on Fickian diffusion. In vitro cytotoxicity assays confirmed the thermo-responsive antitumor activity of DOX-loaded CNPs as the HT-29 cell viability incubated with DOX-loaded CNPs at 42 °C was significantly lower than that at 37 °C. Cellular uptake experiments proved that DOX-loaded CNPs accumulated in the cytoplasm after being endocytosed and promoted DOX release by increasing environment temperature. This study generated stable thermo-sensitive CNPs based on biopolymers, which can be used as potential nanocarriers for the controlled release of anticancer drugs for cancer therapy.

Applications and advancements of polysaccharide-based nanostructures for enhanced drug delivery

Growing demand for highly effective, site-specific delivery of pharmaceuticals and nutraceuticals using nano-sized carriers has prompted increased scrutiny of carrier biocompatibility and biodegradability. To address these concerns, biodegradable natural polymers have emerged as a transformative domain, offering non-toxic, precisely targetable carriers capable of finely modulating cargo pharmacokinetics while generating innocuous decomposition by-products. This comprehensive review illuminates the emergence of polysaccharide-based nanoparticulate drug delivery systems. These systems establish an interactive interface between drug and targeted organs, guided by strategic modifications to polysaccharide backbones, which facilitate the creation of morphologically, constitutionally, and characteristically vibrant nanostructures through various fabrication routes, underpinning their pivotal role in biomedical applications. Advancements crucial to enhancing polysaccharide-based drug delivery, such as surface modifications and bioinspired modifications for enhanced targeting, and stimuli-responsive release, strategies to overcome biological barriers, enhance tumor penetration, and optimize therapeutic outcomes are highlighted. This review also examines some potent challenges, and the contemporary way out of them, and discusses future perspectives in the field.

Carboxymethyl chitosan and octadecylamine-coated liposome-containing WPTS: design, optimization, and evaluation

Liposomes (LPs) are a delivery system for stabilizing pharmaceuticals with limited use due to their propensity to congregate and fuse. A proposed method of addressing these problems is polymer coating. In this study, the potential of octadecylamine (ODA)-coated liposomes and carboxymethyl chitosan (CMCS/ODA-LPs) for enhancing Wacao pentacyclic triterpene saponin (WPTS) transport capacity was investigated. CMCS/ODA-LPs were produced by electrostatic adsorption and thin-film hydration. Response surface methodology (RSM) was employed to enhance the process and encapsulation efficiency (EE) for optimum drug encapsulation efficiency. The synthesized WPTS-CMCS/ODA-LPs were uniformly dispersed in a circular shape, and during 14 days of storage at 4 °C, the particle size and morphology did not significantly change. Vesicle size, zeta potential, polydispersity index (PDI), and entrapment efficiency (%) were 179.1 ± 7.31 nm, -29.6 ± 1.35 mV, 0.188 ± 0.052, and 75.62 ± 0.43, respectively. The hemolysis test revealed that WPTS-CMCS/ODA-LPs were sufficiently biocompatible. Compared to WPTS-LPs, WPTS-CMCS/ODA-LPs consistently showed a much more significant cytotoxic effect on cancer cells. Early and WPTS-CMCS/ODA-LPs-induced apoptosis resulted in almost seven times more cell death than the control. Compared to physiological pH 7.3, the pH-sensitive CMCS coupled LPs increased drug release at acidic pH 6.5. These findings suggest the efficacy of pH-sensitive CMCS/ODA-LPs as a medication delivery method for WPTS.

Guanidinylated bioactive chitosan-based injectable hydrogels with pro-angiogenic and mechanical properties for accelerated wound closure

Wound healing is a complex process involving the concerted action of many genes and signaling pathways, with angiogenesis being crucial for expediting wound closure. Dressings that possess pro-angiogenic properties are increasingly recognized as attractive candidates for wound care. Drawing inspiration from the active closure of wounds in embryos, we have developed a thermo-responsive hydrogel with mechanoactive properties, combining vascular regeneration and skin wound contraction to accelerate healing. The significant improvement in vascular reconstruction is attributed to the synergistic effect of arginine and deferoxamine (DFO) released from the hydrogels. Additionally, the contraction force of the hydrogel actively promotes skin closure in wounds. Remarkably, groups treated with hydroxybutyl chitosan methacrylate combined with arginine (HBC_m_Arg/DFO) exhibited increased vascularization, and greater wound maturity, leading to enhanced healing. These results highlight the synergistic impact of pro-angiogenic and mechanical properties of the HBC_m_Arg/DFO hydrogel in accelerating wound healing in rats.

Multi-functional chitosan-based nanoparticles for drug delivery: Recent advanced insight into cancer therapy

Cancer therapy continues to be a major global concern, with conventional treatments suffering from low efficacy, untargeted drug delivery, and severe side effects. Recent research in nanomedicine suggests that nanoparticles' unique physicochemical properties can be leveraged to surmount the limitations of conventional cancer treatment. Chitosan-based nanoparticles have gained significant attention due to their high drug-carrying capacity, non-toxicity, biocompatibility, and long circulation time. Chitosan is utilized in cancer therapies as a carrier to accurately deliver active ingredients to tumor sites. This review focuses on clinical studies and current market offerings of anticancer drugs. The unique nature of tumor microenvironments presents new opportunities for the development of smart drug delivery systems, and this review explores the design and preparation of chitosan-based smart nanoparticles. Further, we discuss the therapeutic efficacies of these nanoparticles based on various in vitro and in vivo findings. Finally, we present a forward-looking perspective on the challenges and prospects of chitosan-based nanoparticles in cancer therapy, intending to provide fresh ideas for advancing cancer treatment strategies.

Orally Administrable Therapeutic Nanoparticles for the Treatment of Colorectal Cancer

Colorectal cancer (CRC) is one of the most common and lethal human malignancies worldwide; however, the therapeutic outcomes in the clinic still are unsatisfactory due to the lack of effective and safe therapeutic regimens. Orally administrable and CRC-targetable drug delivery is an attractive approach for CRC therapy as it improves the efficacy by local drug delivery and reduces systemic toxicity. Currently, chemotherapy remains the mainstay modality for CRC therapy; however, most of chemo drugs have low water solubility and are unstable in the gastrointestinal tract (GIT), poor intestinal permeability, and are susceptible to P-glycoprotein (P-gp) efflux, resulting in limited therapeutic outcomes. Orally administrable nanoformulations hold the great potential for improving the bioavailability of poorly permeable and poorly soluble therapeutics, but there are still limitations associated with these regimes. This review focuses on the barriers for oral drug delivery and various oral therapeutic nanoparticles for the management of CRC.

A composite sponge based on alkylated chitosan and diatom-biosilica for rapid hemostasis

Rapid control of bleeding is of great significance in military trauma and traffic accidents. In this study, alkylated chitosan (AC) and diatom biosilica (DB) were combined to develop a safe and effective hemostatic composite sponge (AC-DB sponge) for hemorrhage control. Due to the procoagulant chemical structure of AC-DB sponge, it exhibited rapid hemostatic ability in vitro (clotting time was shortened by 78% than that of control group), with favorable biocompatibility (hemolysis ratio < 5%, no cytotoxicity). The strong interface effect between AC-DB sponge and blood induced the erythrocyte and platelets activation, deformation and aggregation, intrinsic coagulation pathway activation, resulting in significant coagulation acceleration. AC-DB sponge had excellent performance in in vivo assessments with shortest clotting time (106.2 s) and minimal blood loss (328.5 mg). All above results proved that AC-DB sponge had great potential to be a safe and rapid hemostatic material.

Investigation into the physical properties, antioxidant and antibacterial activity of Bletilla striata polysaccharide/chitosan membranes

Traditional wound dressings and formulations, such as cream, gauze, cotton wool and gel, are disadvantaged by short residence time, poor leakage and air permeability, poor patient compliance, and the minimal preservation in wet environment. This study is purposed to develop new biodegradable, antioxidant, and antimicrobial membranes based on two natural polysaccharides, Bletilla striata polysaccharide (BSP) and chitosan (CS). The developed films were characterized by SEM, FTIR spectroscopy, NMR spectroscopy and X-ray diffraction to examine surface morphology and internal structure, while TG analysis was conducted to explore the thermal properties of the films. The physical properties of the films were also improved significantly after the introduction of BSP. The biological activity of developed films was assessed by means of antioxidant and antibacterial assay for the further research as a potential wound dressing. The CCK-8 assay revealed that the developed films showed a significant improvement of cell viability, biocompatibility and non-toxicity. These researches demonstrated that BSP/CS films can be applied as suitable materials for the development of biomaterial matrix in novel wound dressing.

Nanogels Capable of Triggered Release

This chapter provides an overview of soft and environmentally sensitive polymeric nanosystems, which are widely known as nanogels. These particles keep great promise to the area of drug delivery due to their high biocompatibility with body fluids and tissues, as well as due to their ability to encapsulate and release the loaded drugs in a controlled manner. For a long period of time, the controlled drug delivery systems were designed to provide long-termed or sustained release. However, some medical treatments such as cancer chemotherapy, protein and gene delivery do not require the prolonged release of the drug in the site of action. In contrast, the rapid increase of the drug concentration is needed for gaining the desired biological effect. Being very sensitive to surrounding media and different stimuli, nanogels can undergo physico-chemical transitions or chemical changes in their structure. Such changes can result in more rapid release of the drugs, which is usually referred to as triggered drug release. Herein we give the basic information on nanogel unique features, methods of sensitive nanogels preparation, as well as on main mechanisms of triggered release. Additionally, the triggered release of low-molecular drugs and biomacromolecules are discussed.

Thermoresponsive Chitosan/DOPA-Based Hydrogel as an Injectable Therapy Approach for Tissue-Adhesion and Hemostasis

Chitosan (CS) hydrogels are widely used in wound hemostatic agents due to their superior biocompatibility, biodegradability, and hemostatic effect. However, most of them fail to achieve great hemostatic effect because of poor adhesion to bleeding tissues. Also, the conventional implantation surgery of hemostatic hydrogels to internal bleeding wounds may cause secondary trauma to the human body. In this work, catechol-hydroxybutyl chitosan (HBCS-C) has been designed and prepared by grafting hydroxybutyl groups and catechol groups to the CS backbones. The multifunctional HBCS-C hydrogels are fabricated with the properties of thermosensitivity, injectability, tissue-adhesion, biodegradation, biocompatibility, and wound hemostasis. They exhibit excellent liquid-gel transition at different temperatures, through the changes of hydrophilic-hydrophobic interaction and hydrogen bonds generating from hydroxybutyl groups. By the multiple interactions between catechol groups/amino groups and tissues, the biocompatible hydrogels can strongly adhere on the surface of tissue. To further study, the bleeding rat-liver models are made to evaluate the hemostatic effects. After injecting the hydrogel precursor solution into the rat body, the hydrogels are not only formed in situ within 30 s but are also firmly adhered to the bleeding tissues which shows effective hemostasis. The injectability and tissue-adhesion improvement in this study gives a new insight into hemostatic agents, and the multifunctional hydrogels have a great potential in the biomedical application.

Gastric environment-stable oral nanocarriers for in situ colorectal cancer therapy

Colorectal cancer (CRC) is a prevalent and fatal cancer. Oral administration provided the potential for in situ treatment of the colorectal cancer. However, drugs couldn't be well-absorbed mainly due to its degradation in the gastric area and poor intestinal permeability. In this study, we synthesized deoxycholic acid and hydroxybutyl decorated chitosan nanoparticles (DAHBC NPs) as oral curcumin (CUR) delivery system for colorectal cancer treatment. DAHBC with lower critical solution temperature (LCST) below 37 °C (27-33 °C) was obtained. DAHBC NPs were correspondingly stable in simulated gastric conditions (pH 1.2, 37 °C), due to the offset of size change between pH-responsive expansion and thermo-responsive shrinkage. In simulated intestinal tract (pH 7.0-7.4, 37 °C), DAHBC NPs exhibited burst release of CUR owing to the onefold effect of thermo-responsive shrinkage. DAHBC27 NPs showed the minimum CUR leakage (~10%) in simulated gastric conditions, because a furthest temperature-sensitive shrinkage caused by the lowest LCST offset the expansion in acid environment. DAHBC27 NPs induced ~10-fold increased (P < 0.05) CUR absorption by paracellular transport pathway, compared to the free CUR. Thus, DAHBC NPs stabilized in the gastric environment may be a promising oral drugs delivery system for effective in situ colorectal cancer therapy.

Thermoresponsive polymer nanocarriers for biomedical applications

Polymer nanocarriers allow drug encapsulation leading to fragile molecule protection from early degradation/metabolization, increased solubility of poorly soluble drugs and improved plasmatic half-life. However, efficiently controlling the drug release from nanocarriers is still challenging. Thermoresponsive polymers exhibiting either a lower critical solution temperature (LCST) or an upper critical solution temperature (UCST) in aqueous medium may be the key to build spatially and temporally controlled drug delivery systems. In this review, we provide an overview of LCST and UCST polymers used as building blocks for thermoresponsive nanocarriers for biomedical applications. Recent nanocarriers based on thermoresponsive polymer exhibiting unprecedented features useful for biomedical applications are also discussed. While LCST nanocarriers have been studied for over two decades, UCST nanocarriers have recently emerged and already show great potential for effective thermoresponsive drug release.

Comparative Evaluation of Biological Performance, Biosecurity, and Availability of Cellulose-Based Absorbable Hemostats

Hemorrhage remains a leading cause of death after trauma, and developing a hemostat with excellent performance and good biosecurity is an extremely active area of research and commercial product development. Although oxidized regenerated cellulose (ORC) has been developed to address these problems, it is not always efficient and its biosecurity is not perfect. We aimed to refine ORC via a simple and mild neutralization method. The prepared neutralized oxidized regenerated cellulose (NORC) showed a superior gel property due to its chemical structure. The biological performance of both ORC and NORC was systematically evaluated; the results showed that ORC would induce erythema and edema in the irritation test, whereas NORC did not cause any adverse inflammation, indicating NORC had desirable biocompatibility. We further demonstrated that NORC confirmed to the toxicity requirements of International Organization for Standardization (ISO) standards; however, ORC showed an unacceptable cytotoxicity. The rabbit hepatic defect model stated that NORC exhibited better ability of hemostasis, which was attributed to its significant gel performance in physiological environment.