Controlled pH- and glucose-responsive drug release behavior of cationic chitosan based nano-composite hydrogels by using graphene oxide as drug nanocarrier

Biocompatible hydrogels based on quaternary ammonium salts of chitosan with high antimicrobial activity as biocidal agents for disinfection

The paper reports new hydrogels based on quaternary ammonium salts of chitosan designed as biocidal products. The chitosan derivative was crosslinked with salicylaldehyde via reversible imine bonds and supramolecular self-assemble to give dynamic hydrogels which respond to environmental stimuli. The crosslinking mechanism was demonstrated by 1H NMR and FTIR spectroscopy, and X-ray diffraction and polarized light microscopy. The hydrogel nature, self-healing and thixotropy were proved by rheological investigation and visual observation, and their morphology was assessed by scanning electron microscopy. The relevant properties for application as biocidal products, such as swelling, dissolution, bioadhesiveness, antimicrobial activity and ex-vivo hemocompatibility and in vivo local toxicity and biocompatibility on experimental mice were measured and analyzed in relationship with the imination degree and the influence of each component. It was found that the hydrogels are superabsorbent, have good adhesivity to skin and various surfaces and antimicrobial activity against relevant gram-positive and gram-negative bacteria, while being hemocompatible and biocompatible. Besides, the hydrogels are easily biodegraded in soil. All these properties recommend the studied hydrogels as ecofriendly biocidal agents for living tissues and surfaces, but also open the perspectives of their use as platform for in vivo applications in tissue engineering, wound healing, or drug delivery systems.

Electrovalent effects of sodium carboxymethyl cellulose and hydroxyethyl cellulose on regeneration of empty fruit bunch cellulose to a superabsorbent hydrogel

The hydrogel regeneration process, involving various cellulose types, results in distinct chemical bonding patterns. Even minor variations in chemical interactions among polymers during regeneration significantly impact properties like hydrogel-forming ability, hydrophilicity, and swelling capacity. This study focuses on regenerating a superabsorbent hydrogel from the interplay of native empty fruit bunch cellulose (EFBC), sodium carboxymethyl cellulose (NaCMC), and hydroxyethyl cellulose (HEC) using epichlorohydrin (ECH) as a crosslinker. The hydrogel was formed from dissolved EFBC solutions in an aqueous NaOH/urea solvent, supplemented with different NaCMC and HEC weight ratios, and ECH chemically assisted the crosslinking process. EFBC provides the hydrogel's supporting skeletal structure, while NaCMC and HEC play vital roles in enhancing forming ability and its physical and mechanical properties through diverse chemical interactions based on their electrovalent properties. Notably, NaCMC imparts hydrophilicity, while HEC indirectly improves superabsorbent properties through the enhancement of the elastic network's retraction force. Hydrogels combining NaCMC and HEC show a remarkable water absorption capacity exceeding 30,000 %, surpassing those regenerated solely with EFBC and NaCMC. The highest swelling, over 130,000 %, is achieved with 0.75 % NaCMC and 0.25 % HEC. Regarding thermal stability, hydrogels with a higher NaCMC proportion outperform those with increased HEC content. The study highlights the critical role of tailored chemical interactions in successfully regenerating an improved superabsorbent hydrogel with enhanced water absorption properties.

Graphene oxide-based nanocomposites for outstanding eco-friendly antifungal potential against tomato phytopathogens

To obtain the collaborative antifungal potential of nanocomposites conjugated with graphene oxide (GO), a combination of GO with chitosan (CS/GO) and GO with chitosan (CS) and polyaniline (PANI/CS/GO) was carried out. The synthesized GO-nanocomposites were recognized by several techniques. Vanillin (Van.) and cinnamaldehyde (Cinn.) were loaded on the prepared nanocomposites as antioxidants through a batch adsorption process. In vitro release study of Van. and Cinn. from the nanocomposites was accomplished at pH 7 and 25°C. The antimicrobial activity of GO, CS/GO, and PANI/CS/GO was studied against tomato Fusarium oxysporum (FOL) and Pythium debaryanum (PYD) pathogens. The loaded ternary composite PANI/CS/GO exhibited the best percent of reduction against the two pathogens in vitro studies. The Greenhouse experiment revealed that seedlings' treatment by CS/GO/Van. and PANI/CS/GO/Van significantly lowered both disease index and disease incidence. The loaded CS/GO and PANI/CS/GO nanocomposites had a positive effect on lengthening shoots. Additionally, when CS/GO/Cinn., CS/GO/Van. and PANI/CS/GO/Van. were used, tomato seedlings' photosynthetic pigments dramatically increased as compared to infected control. The results show that these bio-nanocomposites can be an efficient, sustainable, nontoxic, eco-friendly, and residue-free approach for fighting fungal pathogens and improving plant growth.

Current status of porous coordination networks (PCNs) derived porphyrin spacers for cancer therapy

INTRODUCTION

Porous coordination networks (PCNs) have been widely used in large number of applications such as light harvesting, catalysis, and biomedical applications. Inserting porphyrins into PCNs scaffolds can alleviate the solubility and chemical stability problems associated with porphyrin ligands and add functionality to PCNs. The discovery that some PCNs materials have photosensitizer and acoustic sensitizer properties has attracted significant attention in the field of biomedicine, particularly in cancer therapy. This article describes the latest applications of the porphyrin ligand-based family of PCNs in cancer chemodynamic therapy (CDT), photodynamic therapy (PDT), sonodynamic therapy (SDT), photothermal therapy (PTT), and combination therapies and offers some observations and reflections on them.

AREAS COVERED

This article discusses the use of the PCN family of MOFs in cancer treatment, specifically focusing on chemodynamic therapy, sonodynamic therapy, photodynamic therapy, photothermal therapy, and combination therapy.

EXPERT OPINION

Although a large number of PCNs have been developed for use in novel cancer therapeutic approaches, further improvements are needed to advance the use of PCNs in the clinic. For example, the main mechanism of action of PCNs against cancer and the metabolic processes in organisms, and how to construct PCNs that maintain good stability in the complex environment of organisms.

Chitosan-Based Antibacterial Films for Biomedical and Food Applications

Antibacterial chitosan films, versatile and eco-friendly materials, have garnered significant attention in both the food industry and medicine due to their unique properties, including biodegradability, biocompatibility, and antimicrobial activity. This review delves into the various types of chitosan films and their distinct applications. The categories of films discussed span from pure chitosan films to those enhanced with additives such as metal nanoparticles, metal oxide nanoparticles, graphene, fullerene and its derivatives, and plant extracts. Each type of film is examined in terms of its synthesis methods and unique properties, establishing a clear understanding of its potential utility. In the food industry, these films have shown promise in extending shelf life and maintaining food quality. In the medical field, they have been utilized for wound dressings, drug delivery systems, and as antibacterial coatings for medical devices. The review further suggests that the incorporation of different additives can significantly enhance the antibacterial properties of chitosan films. While the potential of antibacterial chitosan films is vast, the review underscores the need for future research focused on optimizing synthesis methods, understanding structure-property relationships, and rigorous evaluation of safety, biocompatibility, and long-term stability in real-world applications.

Rheological Properties of Different Graphene Nanomaterials in Biological Media

Carbon nanomaterials have received increased attention in the last few years due to their potential applications in several areas. In medicine, for example, these nanomaterials could be used as contrast agents, drug transporters, and tissue regenerators or in gene therapy. This makes it necessary to know the behavior of carbon nanomaterials in biological media to assure good fluidity and the absence of deleterious effects on human health. In this work, the rheological characterization of different graphene nanomaterials in fetal bovine serum and other fluids, such as bovine serum albumin and water, is studied using rotational and microfluidic chip rheometry. Graphene oxide, graphene nanoplatelets, and expanded graphene oxide at concentrations between 1 and 3 mg/mL and temperatures in the 25–40 °C range were used. The suspensions were also characterized by transmission and scanning electron microscopy and atomic force microscopy, and the results show a high tendency to aggregation and reveals that there is a protein–nanomaterial interaction. Although rotational rheometry is customarily used, it cannot provide reliable measurements in low viscosity samples, showing an apparent shear thickening, whereas capillary viscometers need transparent samples; therefore, microfluidic technology appears to be a suitable method to measure low viscosity, non-transparent Newtonian fluids, as it is able to determine small variations in viscosity. No significant changes in viscosity are found within the solid concentration range studied but it decreases between 1.1 and 0.6 mPa·s when the temperature raises from 25 to 40 °C.

Synthesis of an insulin intercalated graphene oxide nanogel composite: evaluation of its release profile and stability for oral delivery of insulin

Diabetes mellitus (DM) is a disorder of glucose regulation produced due to insufficient availability of insulin. Generally, insulin is given to diabetes patients via subcutaneous injection which is a painful method to deliver this drug. In this work we have made an attempt to develop an oral drug delivery system that can efficiently deliver insulin to the small intestine. An insulin intercalated GO based nanogel composite (In@GO NgC) was fabricated for oral delivery of insulin. The in vitro release of insulin from In@GO NgC was studied in artificial gastric (pH 1.2) and intestinal (pH 7.5) fluids. The In@GO NgC produced better release in artificial intestinal fluid as compared to gastric fluid. The enzymatic degradation of released insulin was also examined and the results revealed that even after 6 h of incubation, the gel remained stable and the un-degraded insulin seemed to be sufficient for the physiological processes. The efficacy of In@GO NgC was also confirmed by comparing its release profile with non-intercalated GO NgC and nanogel (Ng) without GO. The prepared nanogels were thoroughly characterized using FTIR, SEM, EDS, DSC and DLS. The better release profile and enzymatic stability of In@GO NgC suggests that it can be utilized for oral drug delivery of insulin.

Biomedical applications of chitosan-graphene oxide nanocomposites

Chitosan (CS) and graphene oxide (GO) nanocomposites have received wide attention in biomedical fields due to the synergistic effect between CS which has excellent biological characteristics and GO which owns great physicochemical, mechanical, and optical properties. Nanocomposites based on CS and GO can be fabricated into a variety of forms, such as nanoparticles, hydrogels, scaffolds, films, and nanofibers. Thanks to the ease of functionalization, the performance of these nanocomposites in different forms can be further improved by introducing other functional polymers, nanoparticles, or growth factors. With this background, the current review summarizes the latest developments of CS-GO nanocomposites in different forms and compositions in biomedical applications including drug and biomacromolecules delivery, wound healing, bone tissue engineering, and biosensors. Future improving directions and challenges for clinical practice are proposed as well.

Hyaluronic Acid and Graphene Oxide-incorporated Hyaluronic Acid Hydrogels for Electrically Stimulated Release of Anticancer Tamoxifen Citrate

Transdermal drug delivery is the transport of drug across the skin and into the systemic circulation. Patch is a one of transdermal device that is used to attach on skin and contains drug. The drug matrices from hyaluronic acid (HA) and graphene oxide (GO) incorporated HA hydrogel were fabricated for the release of tamoxifen citrate (TMX) as the anticancer drug under applied electrical field. The pristine HA hydrogels as the matrix and GO as the drug encapsulation host were fabricated for transdermal patch by the solution casting using citric acid as the chemical crosslinker. In vitro drug release experiment was investigated by utilizing the modified Franz-diffusion cell under the effects of crosslinking ratio, electric potential, and GO. The TMX release behaviors from the hydrogels were found to be from the three mechanisms: the pure Fickian diffusion; the anomalous or non-Fickian diffusion; and Super case II transport depending on the crosslinking conditions. The TMX diffusion and release amount from the pristine HA hydrogels were increased with smaller crosslinking ratios. With applied electrical potential, the enhanced TMX diffusion and release amount were observed when compared to that without due to the electro-repulsive force. Furthermore, the TMX diffusion from the HA hydrogel with GO as the drug encapsulation host was higher by two orders of magnitude than without GO.

Surface Engineered PLGA Nanoparticle for Threshold Responsive Glucose Monitoring and "Self-Programmed" Insulin Delivery

We have developed a reversible, biocompatible, "self-programmed" PLGA [poly(lactic-co-glycolic acid)] nanoparticle-based optical biosensor capable of sensing and continuous monitoring of glucose above the physiologically relevant threshold value (100-125 mg/dL) as well as "on-demand" insulin delivery via an "On-Off" technique. We have carefully surface engineered the PLGA nanoparticle using amino dextran-fluorescein (A-DexFl) and amino-phenyl boronic acid (A-PBA) to exploit the binding affinity of boronic acids with that of cis-1,2 diols of dextran/glucose. Initially, the dextran chains wrap the nanoparticle surface due to its high affinity toward A-PBA (K_b = 6.1 × 10⁶ M^-1). The close proximity of the fluorophores with that of A-PBA quenches the fluorescence, resulting in an "Off" state. On the addition of glucose, it competes with A-DexFl to bind with A-PBA. Above a certain threshold concentration of glucose, the binding affinity overcomes (K_b = 6.3 × 10⁷ M^-1) the dextran-A-PBA binding. This opens-up the wrapped A-DexFl chains from the nanoparticle surface and results in an increased distance between the fluorophore and A-PBA, triggering the "On" state. The activation of the On-Off state can be finely tuned in the desired range of physiologically relevant glucose concentrations by varying the ligand ratios on the PLGA surface. The nanoparticle core has also been used as an insulin reservoir to trigger the drug release in the "On" state. We have obtained ∼53% encapsulation efficiency and ∼20% loading efficiency for insulin loading. Once the glucose concentration falls beyond the detection range, the dextran chains collapse on the nanoparticle surface with a suspension in drug release. The process is solely controlled by the competition and multivalent binding affinity between glucose, A-DexFl, and A-PBA, which allows it to be "self-programmed" and "self-regulated" with continuous monitoring up to 8-10 cycles over a 72 h time period. A sustained drug release has been found with ∼70% of released drug over a period of 72 h, although this release is insignificant in the absence of glucose. Several control experiments have been performed to optimize the sensor design.

Recent Applications of Dual-Stimuli Responsive Chitosan Hydrogel Nanocomposites as Drug Delivery Tools

Polysaccharides are a versatile class of macromolecules that are involved in many biological interactions critical to life. They can be further modified for added functionality. Once derivatized, these polymers can exhibit new chemical properties that can be further optimized for applications in drug delivery, wound healing, sensor development and others. Chitosan, derived from the N-deacetylation of chitin, is one example of a polysaccharide that has been functionalized and used as a major component of polysaccharide biomaterials. In this brief review, we focus on one aspect of chitosan's utility, namely we discuss recent advances in dual-responsive chitosan hydrogel nanomaterials.

Gelatin-Graphene Oxide Nanocomposite Hydrogels for Kluyveromyces lactis Encapsulation: Potential Applications in Probiotics and Bioreactor Packings

Nutraceutical formulations based on probiotic microorganisms have gained significant attention over the past decade due to their beneficial properties on human health. Yeasts offer some advantages over other probiotic organisms, such as immunomodulatory properties, anticancer effects and effective suppression of pathogens. However, one of the main challenges for their oral administration is ensuring that cell viability remains high enough for a sustained therapeutic effect while avoiding possible substrate inhibition issues as they transit through the gastrointestinal (GI) tract. Here, we propose addressing these issues using a probiotic yeast encapsulation strategy, Kluyveromyces lactis, based on gelatin hydrogels doubly cross-linked with graphene oxide (GO) and glutaraldehyde to form highly resistant nanocomposite encapsulates. GO was selected here as a reinforcement agent due to its unique properties, including superior solubility and dispersibility in water and other solvents, high biocompatibility, antimicrobial activity, and response to electrical fields in its reduced form. Finally, GO has been reported to enhance the mechanical properties of several materials, including natural and synthetic polymers and ceramics. The synthesized GO-gelatin nanocomposite hydrogels were characterized in morphological, swelling, mechanical, thermal, and rheological properties and their ability to maintain probiotic cell viability. The obtained nanocomposites exhibited larger pore sizes for successful cell entrapment and proliferation, tunable degradation rates, pH-dependent swelling ratio, and higher mechanical stability and integrity in simulated GI media and during bioreactor operation. These results encourage us to consider the application of the obtained nanocomposites to not only formulate high-performance nutraceuticals but to extend it to tissue engineering, bioadhesives, smart coatings, controlled release systems, and bioproduction of highly added value metabolites.

Can nanoparticles and nano‒protein interactions bring a bright future for insulin delivery?

Insulin therapy plays an essential role in the treatment of diabetes mellitus. However, frequent injections required to effectively control the glycemic levels lead to substantial inconvenience and low patient compliance. In order to improve insulin delivery, many efforts have been made, such as developing the nanoparticles (NPs)-based release systems and oral insulin. Although some improvements have been achieved, the ultimate results are still unsatisfying and none of insulin-loaded NPs systems have been approved for clinical use so far. Recently, nano‒protein interactions and protein corona formation have drawn much attention due to their negative influence on the in vivo fate of NPs systems. As the other side of a coin, such interactions can also be used for constructing advanced drug delivery systems. Herein, we aim to provide an insight into the advance and flaws of various NPs-based insulin delivery systems. Particularly, an interesting discussion on nano‒protein interactions and its potentials for developing novel insulin delivery systems is initiated.

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Insulin therapy plays essential roles in treating diabetes.

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Optimizing insulin delivery enhances insulin therapy.

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Nanoparticles are promising systems for delivery of insulin.

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Nano-protein interactions influence the delivery of nanoparticles.

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Nano-protein interactions can be used for advanced delivery of insulin.

Functional Chitosan-based Materials for Biological Applications

Background:

Bio-based materials, as the plentiful and renewable resources for natural constituents which are essential for biomedical and pharmaceutical applications, have not been exploited adequately yet. Chitosan is a naturally occurring polysaccharide obtained from chitin, which has recently attracted widespread attention owing to its excellent activity. This review shows the methods of extraction and modification of chitosan and provides recent progress of synthesis and use of chitosan-based materials in biological applications.

Methods:

By consulting the research literature of the last decade, the recent progresses of functional chitosan-based materials for biological applications were summarized and divided into the methods of extraction chitosan, the chemical modification of chitosan, chitosan-based materials for biological applications were described and discussed.

Results:

Chemical modification of chitosan broadens its applications, leading to developing numerous forms of chitosan-based materials with excellent properties. The excellent bioactivity of chitosan-based material enables it serves potential applications in biomedical fields.

Conclusion:

Chitosan-based materials not only exhibit the excellent activities of chitosan but also show other appealing performance of combined materials, even give the good synergistic properties of chitosan and its composite materials. Further studies are needed to define the ideal physicochemical properties of chitosan for each type of biomedical applications. The development of various functional chitosan-based materials for biological applications will be an important field of research, and this kind of material has important commercial value.

Simultaneous Delivery of antimiR-21 and Doxorubicin by Graphene Oxide for Reducing Toxicity in Cancer Therapy

Graphene oxide (GO) has been studied by many researchers for its potential drug-delivery value. In order to reduce the side effects of anticancer drugs by decreasing the dosage and maintain the therapeutic effects, a dual drug-delivery system that used GO as a carrier and simultaneously loaded with antitumor drugs and antimir-21 was rationally designed for the cooperative treatment of tumors. Results obtained from our studies have found that MDA-MB-231 cells were inhibited in low Dox dose. The outcomes of confocal microscopy indicated that Dox and antimiR-21 could be released rapidly in cancer cells, which is good for killing cancer cells. In addition, qRT-PCR further demonstrated that miR-21 was silenced by antimiR-21. Consequently, GO has a great potential to codeliver chemotherapeutic drugs and gene drugs in cancer combination therapy for reducing toxicity.

Mechanism of Controlled Release of Vancomycin from Crumpled Graphene Oxides

The physical and chemical interactions with vancomycin (VAN) were accessed between graphene oxide (GO) and crumpled graphene oxide (CGO) to present the possible loading and release mechanisms. The improved hydrophilicity and surface charge were found on CGO through water contact angle and ζ-potential measurements. Fourier transform infrared and X-ray photoelectron spectroscopies confirmed the attachment of VAN onto CGO or GO through π-π stacking and hydrogen bonding. Both CGO-VAN and GO-VAN drug complexes showed pH-controlled release property. The high VAN loading and delayed release in CGO-VAN system were mainly due to the crumpled morphology.

Dual-Sensitive Graphene Oxide Loaded with Proapoptotic Peptides and Anticancer Drugs for Cancer Synergetic Therapy

A dual-sensitive drug delivery system (DDS) based on graphene oxide (GO) which is simultaneously loaded with proapoptotic peptides and anticancer drugs was rationally designed and fabricated for cancer synergetic therapy. Specifically, a kind of cell apoptosis peptide (KLAKLAK)₂ (KLA) was anchored on the surface of GO via a disulfide bond to obtain GO-SS-KLA. Then, the aromatic anticancer drug doxorubicin (DOX) was loaded on GO through π-π conjugation and hydrogen bonding interactions. Finally, bovine serum albumin (BSA) was used to coat the GO carrier to obtain a biological medium-stable GO-based DDS, DOX@GO-SS-KLA/BSA. The results show that KLA and DOX can be released responding to the reductive and pH stimulus inside the cells, respectively, and achieve a synergetic therapy for cancer. Moreover, the results of stability studies show that DOX@GO-SS-KLA/BSA could be stably dispersed in water for more than 8 days and in 10% fetal bovine serum for at least 6 days. The constructed DOX@GO-SS-KLA/BSA exhibits great potential as a drug carrier for co-delivery of various therapeutic agents.

Stimuli-responsive bio-based polymeric systems and their applications

This article highlights the properties of stimuli-responsive bio-based polymeric systems and their main intelligent applications.

Non-dye cell viability monitoring by using pH-responsive inverse opal hydrogels

Recent advances in the field of drug screening focus on accurate, rapid and high-throughput screening methods. In our work, hydrogel inverse opal photonic crystal microspheres (HPCMs) were fabricated through a templating method and exhibited a robust and reversible response to temperature and pH. The response performance was tested under various temperature (25-55 °C) and pH (1.5-7.5) conditions and the reflective peak shifted noticeably within the visible wavelength range. Furthermore, HPCMs were used as drug delivery carriers and not only displayed high doxorubicin (DOX) drug loading but also presented thermo/pH-induced drug release properties. More importantly, these carriers were shown to be good reporters for monitoring cell viability due to their tunable colour variation. This capability was applied to H460 cell cultures with or without DOX. The structure colour of HPCMs varied in different cell culture microenvironments, and cell apoptosis was able to be distinguished. In this way, this fast, non-dyeing method for reporting cell viability in tumour cytotoxicity assays has potential in the field of drug screening and may give new insights into the use of structural colour to report results in drug screening systems.

pH Sensitive Hydrogels in Drug Delivery: Brief History, Properties, Swelling, and Release Mechanism, Material Selection and Applications

Improving the safety efficacy ratio of existing drugs is a current challenge to be addressed rather than the development of novel drugs which involve much expense and time. The efficacy of drugs is affected by a number of factors such as their low aqueous solubility, unequal absorption along the gastrointestinal (GI) tract, risk of degradation in the acidic milieu of the stomach, low permeation of the drugs in the upper GI tract, systematic side effects, etc. This review aims to enlighten readers on the role of pH sensitive hydrogels in drug delivery, their mechanism of action, swelling, and drug release as a function of pH change along the GI tract. The basis for the selection of materials, their structural features, physical and chemical properties, the presence of ionic pendant groups, and the influence of their pKa and pKb values on the ionization, consequent swelling, and targeted drug release are also highlighted.