Developing regulatory property of gelatin-tannic acid multilayer films for coating-based nitric oxide gas delivery system

Gelatin-Based Adhesive Hydrogels with Self-Healing, Injectable and Temperature-Triggered Detachable Properties

Adhesive hydrogels are emerging as attractive functional materials for various fields, such as tissue engineering, wound healing, E-skins, etc. However, the removal of adhesive hydrogels from covered area may be painful and cause a secondary damage. In the current study, gelatin-based hydrogels are prepared by cross-linking with tannic acid and 4-formylphenyl boronic acid, through simultaneous dynamic covalent boronic ester and imine bond formations. The obtained hydrogels not only present self-healing and injectable properties, but also show tunable adhesiveness that regulated by temperature and oxidation degrees of tannic acid. The maximum adhesion strength of the hydrogels with medium oxidation degree at 37 °C can be measured up to 30 kPa on porcine skin, while the value decreased to ≈10 kPa at lowered temperature of 25 °C, facilitating the unpainful removal of the hydrogels from skins. This work provides a new approach for the design of functional hydrogels with tailorable adhesiveness.

Mucoadhesive Enhancement of Gelatine by Tannic Acid Crosslinking for Buccal Application

This study aims to evaluate the impact of formulation parameters on tannic acid-crosslinked gelatine (GelTA) films, intended as a mucoadhesive matrix for extended buccal drug delivery. GelTA films were prepared using the solvent evaporation technique and screened based on their mucoadhesive and dissolution characteristics. The formulation variables included the source of gelatine (bovine and fish), tannic acid concentration, pH of the film-forming solutions, and the type and concentration of plasticisers. Subsequently, selected films underwent further characterisation (e.g., crosslinking density, stability) to elucidate their features as a drug delivery matrix. GelTA films exhibited a significantly improved dissolution time compared to the non-crosslinked film (BG-GLY20), while maintaining a substantial water uptake capacity conducive to a matrix system with extended action. The bovine GelTA film containing 5% w/w tannic acid and 20% w/w glycerine, prepared at pH 7 (BG-GLY20-7), exhibited a 1.6-fold increase in mucoadhesivity and an extended dissolution time of up to 6 h compared to BG-GLY20 (control), along with superior antioxidant and antimicrobial properties. However, stability studies indicate the need for an oxygen-free environment for film storage. In conclusion, GelTA films show promise as a buccal film matrix, offering extended dissolution times, substantial water uptake, and enhanced adhesive strength.

Protein-based layer-by-layer films for biomedical applications

The surface engineering of biomaterials is crucial for their successful (bio)integration by the body, i.e. the colonization by the tissue-specific cell, and the prevention of fibrosis and/or bacterial colonization. Performed at room temperature in an aqueous medium, the layer-by-layer (LbL) coating method is based on the alternating deposition of macromolecules. Versatile and simple, this method allows the functionalization of surfaces with proteins, which play a crucial role in several biological mechanisms. Possessing intrinsic properties (cell adhesion, antibacterial, degradable, etc.), protein-based LbL films represent a powerful tool to control bacterial and mammalian cell fate. In this article, after a general introduction to the LbL technique, we will focus on protein-based LbL films addressing different biomedical issues/domains, such as bacterial infection, blood contacting surfaces, mammalian cell adhesion, drug and gene delivery, and bone and neural tissue engineering. We do not consider biosensing applications or electrochemical aspects using specific proteins such as enzymes.

Inhalable Nitric Oxide Delivery Systems for Pulmonary Arterial Hypertension Treatment

Pulmonary arterial hypertension (PAH) is a severe medical condition characterized by elevated blood pressure in the pulmonary arteries. Nitric oxide (NO) is a gaseous signaling molecule with potent vasodilator effects; however, inhaled NO is limited in clinical practice because of the need for tracheal intubation and the toxicity of high NO concentrations. In this study, inhalable NO-releasing microspheres (NO inhalers) are fabricated to deliver nanomolar NO through a nebulizer. Two NO inhalers with distinct porous structures are prepared depending on the molecular weights of NO donors. It is confirmed that pore formation can be controlled by regulating the migration of water molecules from the external aqueous phase to the internal aqueous phase. Notably, open porous NO inhalers (OPNIs) can deliver NO deep into the lungs through a nebulizer. Furthermore, OPNIs exhibit vasodilatory and anti-inflammatory effects via sustained NO release. In conclusion, the findings suggest that OPNIs with highly porous structures have the potential to serve as tools for PAH treatment.

Opportunities for Nitric Oxide in Potentiating Cancer Immunotherapy

Despite nearly 30 years of development and recent highlights of nitric oxide (NO) donors and NO delivery systems in anticancer therapy, the limited understanding of exogenous NO's effects on the immune system has prevented their advancement into clinical use. In particular, the effects of exogenously delivered NO differing from that of endogenous NO has obscured how the potential and functions of NO in anticancer therapy may be estimated and exploited despite the accumulating evidence of NO's cancer therapy-potentiating effects on the immune system. After introducing their fundamentals and characteristics, this review discusses the current mechanistic understanding of NO donors and delivery systems in modulating the immunogenicity of cancer cells as well as the differentiation and functions of innate and adaptive immune cells. Lastly, the potential for the complex modulatory effects of NO with the immune system to be leveraged for therapeutic applications is discussed in the context of recent advancements in the implementation of NO delivery systems for anticancer immunotherapy applications. SIGNIFICANCE STATEMENT: Despite a 30-year history and recent highlights of nitric oxide (NO) donors and delivery systems as anticancer therapeutics, their clinical translation has been limited. Increasing evidence of the complex interactions between NO and the immune system has revealed both the potential and hurdles in their clinical translation. This review summarizes the effects of exogenous NO on cancer and immune cells in vitro and elaborates these effects in the context of recent reports exploiting NO delivery systems in vivo in cancer therapy applications.

Nanodiamond enhanced mechanical and biological properties of extrudable gelatin hydrogel cross-linked with tannic acid and ferrous sulphate

Background

The requirements for cell-encapsulated injectable and bioprintable hydrogels are extrusion ability, cell supportive micro-environment and reasonable post-printing stability for the acclimatization of the cells in the target site. Detonation nanodiamond (ND) has shown its potential to improve the mechanical and biological properties of such hydrogels. Enhancing the performance properties of natural biopolymer gelatin-based hydrogels can widen their biomedical application possibilities to various areas including drug delivery, tissue engineering and 3D bioprinting.

Method

In this study, natural cross-linker tannic acid (TA) is used along with ferrous sulphate (FS) to optimize the swelling and disintegration of extrudable and 3D printable gelatin hydrogels. The amounts of TA and FS are restricted to improve the extrusion ability of the gels in 3D printing. Further, ND particles (detonation type) are dispersed using twin screw extrusion technology to study their effect on mechanical and biological properties of the 3D printing hydrogel.

Results

The improved dispersion of ND particles helps to improve compressive strength almost ten times and dynamic modulus three times using 40 mg ND (2% w/w of gelatin). The surface-functional groups of detonation ND also contributed for such improvement in mechanical properties due to higher interaction with the hydrogel matrix. The stability of the hydrogels in water was also improved to 7 days. Four times improvement of the cell growth and proliferation was observed in ND based hydrogel.

Conclusion

The cell-supportive nature of these moderately stable and extrudable ND dispersed gelatin hydrogels makes them a good candidate for short term regenerative applications of cell-encapsulated injectable hydrogels with better mechanical properties.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40824-022-00285-3.

A Novel Strategy for Creating an Antibacterial Surface Using a Highly Efficient Electrospray-Based Method for Silica Deposition

Adhesion of bacteria on biomedical implant surfaces is a prerequisite for biofilm formation, which may increase the chances of infection and chronic inflammation. In this study, we employed a novel electrospray-based technique to develop an antibacterial surface by efficiently depositing silica homogeneously onto polyethylene terephthalate (PET) film to achieve hydrophobic and anti-adhesive properties. We evaluated its potential application in inhibiting bacterial adhesion using both Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) bacteria. These silica-deposited PET surfaces could provide hydrophobic surfaces with a water contact angle greater than 120° as well as increased surface roughness (root mean square roughness value of 82.50 ± 16.22 nm and average roughness value of 65.15 ± 15.26 nm) that could significantly reduce bacterial adhesion by approximately 66.30% and 64.09% for E. coli and S. aureus, respectively, compared with those on plain PET surfaces. Furthermore, we observed that silica-deposited PET surfaces showed no detrimental effects on cell viability in human dermal fibroblasts, as confirmed by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide and live/dead assays. Taken together, such approaches that are easy to synthesize, cost effective, and efficient, and could provide innovative strategies for preventing bacterial adhesion on biomedical implant surfaces in the clinical setting.

Natural Biocidal Compounds of Plant Origin as Biodegradable Materials Modifiers

The article presents a literature review of the plant origin natural compounds with biocidal properties. These compounds could be used as modifiers of biodegradable materials. Modification of polymer material is one of the basic steps in its manufacturing process. Biodegradable materials play a key role in the current development of materials engineering. Natural modifiers are non-toxic, environmentally friendly, and renewable. The substances contained in natural modifiers exhibit biocidal properties against bacteria and/or fungi. The article discusses polyphenols, selected phenols, naphthoquinones, triterpenoids, and phytoncides that are natural antibiotics. Due to the increasing demand for biodegradable materials and the protection of the natural environment against the negative effects of toxic substances, it is crucial to replace synthetic modifiers with plant ones. This work mentions industries where materials containing natural modifying additives could find potential applications. Moreover, the probable examples of the final products are presented. Additionally, the article points out the current world's pandemic state and the use of materials with biocidal properties considering the epidemiological conditions.

Light-Triggered Fluorescence Self-Reporting Nitric Oxide Release from Coumarin Analogues for Accelerating Wound Healing and Synergistic Antimicrobial Applications

Nitric oxide (NO) has an important class of endogenous diatomic molecules that play a key regulatory role in many physiological and biochemical processes. However, the type of nitrosamine NO donor stimulated by light has many advantages compared to the conventional NO donors such as diazeniumdiolates and S-nitrosothiols compounds, including easy synthesis, good stability, and controllable release. In addition, NO release can be regulated by light induction with a built-in calibration mechanism fluorescence. Here, we report that the migration and proliferation of human umbilical vein vascular endothelial cells could be accelerated by the light-triggered NO donors, leading to the angiogenesis. Meanwhile, the screened NO donor 3a with Levofloxacin (Lev) showed synergistic effects to eradicate Methicillin-resistant Staphylococcus aureus (MRSA) biofilms in vitro and treat bacteria-infected wound in vivo.

Unraveling the Structured Solvation Shell of Zwitterion Nanoparticles for Controlled Release of Nitric Oxide

Zwitterions have been attracting emerging attention as an anti-fouling polymer. However, the relationship between structured solvation shells and controlled drug release induced by deceleration of water molecule's translational and vibrational motions of zwitterions is an uncharted territory. Herein, sulfobetaine zwitterion nanoparticles (ZWNPs) were designed as a stable nitric oxide (NO)-delivering carrier. The condensed water structure of the solvation shell at its isoelectric point (PI) and the loose structure of water under different pH conditions were investigated through rheological and thermodynamical analyses. The ZWNPs showed a sustained-release profile at the PI, which presented a structured solvation barrier. On the other hand, NO-loaded ZWNPs showed different release profiles with the burst release at pH 5.5. Notably, an increased cell proliferation rate and a decreased antibacterial effect were observed at the same concentration depending on solvation shell's characteristics.

Natural Compounds and PCL Nanofibers: A Novel Tool to Counteract Stem Cell Senescence

Tissue homeostasis mainly depends on the activity of stem cells to replace damaged elements and restore tissue functions. Within this context, mesenchymal stem cells and fibroblasts are essential for maintaining tissue homeostasis in skin, in particular in the dermis. Modifications in collagen fibers are able to affect stem cell features. Skin properties can be significantly reduced after injuries or with aging, and stem cell niches, mainly comprising extracellular matrix (ECM), may be compromised. To this end, specific molecules can be administrated to prevent the aging process induced by UV exposure in the attempt to maintain a youngness phenotype. NanoPCL-M is a novel nanodevice able to control delivery of Mediterranean plant myrtle (Myrtus communis L.) extracts. In particular, we previously described that myrtle extracts, rich in bioactive molecules and nutraceuticals, were able to counteract senescence in adipose derived stem cells. In this study, we analyzed the effect of NanoPCL-M on skin stem cells (SSCs) and dermal fibroblasts in a dynamic cell culture model in order to prevent the effects of UV-induced senescence on proliferation and collagen depot. The BrdU assay results highlight the significantly positive effect of NanoPCL-M on the proliferation of both fibroblasts and SSCs. Our results demonstrate that-M is able to preserve SSCs features and collagen depot after UV-induced senescence, suggesting their capability to retain a young phenotype.

Enzyme Catalyzed Hydrogel as Versatile Bioadhesive for Tissue Wound Hemostasis, Bonding, and Continuous Repair

Developing a versatile bioadhesive which is biocompatible, adhesive, hemostatic, and therapeutic is of great significance to promote wound sealing and healing. Herein, an adhesive (GTT-3 hydrogel) is fabricated by catalysis of tannic acid modified gelatin (Gel-TA) with transglutaminase (TG). The hydrogen bonding, imine linking, and acyl-transfer reaction between GTT-3 hydrogel and tissue enable efficient hydrogel integration and adhesion to tissue instantly, so as to seal the wound and stop bleeding. Moreover, the intrinsic wound healing ability of gelatin and the antibacterial properties of TA provide favorable conditions for wound healing after adhesion. In vitro mechanical property testing and cell experimental results determine the elasticity, adhesion, and biocompatibility of the GTT-3 hydrogel. The wound operation in mouse models and pathological sectioning results indicate that GTT-3 adhesive obviously accelerates hemostasis, wound bonding, and healing. With the special property of instant adhesion and excellent hemostatic and therapeutic repair effects, GTT-3 hydrogel may provide a new option for surgical operation.

Acceleration of Nitric Oxide Release in Multilayer Nanofilms through Cu(II) Ion Intercalation for Antibacterial Applications

Implant-derived bacterial infection is a prevalent cause of diseases, and no antibacterial coating currently exists that is biocompatible and that does not induce multidrug resistance. To this end, nitric oxide (NO) has been emerging as an effective antimicrobial agent that acts on a broad range of bacteria and elicits no known resistance. Here, a method for accelerating NO release from multilayered nanofilms has been developed for facilitating antibacterial activity. A previously reported multilayered nanofilm (nbi film) was fabricated by alternative deposition of branched polyethyleneimine (BPEI) and alginate via the layer-by-layer assembly method. N-Diazeniumdiolate, a chemical NO donor, was synthesized at the secondary amine moiety of BPEI within the film (nbi/NO film). Cu(II) ions can be incorporated into the film by forming chelating compounds with unreacted amines that have not been converted to NO donors. The increase of the amine protonation state in the chelate caused destabilization of the NO donor by reducing hydrogen bonding between the deprotonated amine and the NO donor. Thus, the Cu(II) ion-embedding film presented accelerated NO release and was further subjected to antibacterial testing to demonstrate the correlation between the NO release rate and the antibacterial activity. This study aimed to establish a novel paradigm for NO-releasing material design based on multilayered nanofilms by presenting the correlation between the NO release rate and the antibacterial effect.

Polymeric Nitric Oxide Delivery Nanoplatforms for Treating Cancer, Cardiovascular Diseases, and Infection

The shortened Abstract is as follows: Therapeutic gas nitric oxide (NO) has demonstrated the unique advances in biomedical applications due to its prominent role in regulating physiological/pathophysiological activities in terms of vasodilation, angiogenesis, chemosensitizing effect, and bactericidal effect. However, it is challenging to deliver NO, due to its short half-life (<5 s) and short diffusion distances (20-160 µm). To address these, various polymeric NO delivery nanoplatforms (PNODNPs) have been developed for cancer therapy, antimicrobial and cardiovascular therapeutics, because of the important advantages of polymeric delivery nanoplatforms in terms of controlled release of therapeutics and the extremely versatile nature. This reviews highlights the recent significant advances made in PNODNPs for NO storing and targeting delivery. The ideal and unique criteria that are required for PNODNPs for treating cancer, cardiovascular diseases and infection, respectively, are summarized. Hopefully, effective storage and targeted delivery of NO in a controlled manner using PNODNPs could pave the way for NO-sensitized synergistic therapy in clinical practice for treating the leading death-causing diseases.

A Hydrogen-Bonded Extracellular Matrix-Mimicking Bactericidal Hydrogel with Radical Scavenging and Hemostatic Function for pH-Responsive Wound Healing Acceleration

Generation of reactive oxygen species, delayed blood clotting, prolonged inflammation, bacterial infection, and slow cell proliferation are the main challenges of effective wound repair. Herein, a multifunctional extracellular matrix-mimicking hydrogel is fabricated through abundant hydrogen bonding among the functional groups of gelatin and tannic acid (TA) as a green chemistry approach. The hydrogel shows adjustable physicochemical properties by altering the concentration of TA and it represents high safety features both in vitro and in vivo on fibroblasts, red blood cells, and mice organs. In addition to the merit of facile encapsulation of cell proliferation-inducing hydrophilic drugs, accelerated healing of skin injury is obtained through pH-dependent release of TA and its multifaceted mechanisms as an antibacterial, antioxidant, hemostatic, and anti-inflammatory moiety. The developed gelatin-TA (GelTA) hydrogel also shows an outstanding effect on the formation of extracellular matrix and wound closure in vivo via offered cell adhesion sites in the backbone of gelatin that provide increased re-epithelialization and better collagen deposition. These results suggest that the multifunctional GelTA hydrogel is a promising candidate for the clinical treatment of full-thickness wounds and further development of wound dressing materials that releases active agents in the neutral or slightly basic environment of infected nonhealing wounds.

Incorporation and antimicrobial activity of nisin Z within carrageenan/chitosan multilayers

An antimicrobial peptide, nisin Z, was embedded within polyelectrolyte multilayers (PEMs) composed of natural polysaccharides in order to explore the potential of forming a multilayer with antimicrobial properties. Using attenuated total reflection Fourier transform infrared spectroscopy (ATR FTIR), the formation of carrageenan/chitosan multilayers and the inclusion of nisin Z in two different configurations was investigated. Approximately 0.89 µg cm-2 nisin Z was contained within a 4.5 bilayer film. The antimicrobial properties of these films were also investigated. The peptide containing films were able to kill over 90% and 99% of planktonic and biofilm cells, respectively, against Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) strains compared to control films. Additionally, surface topography and wettability studies using atomic force microscopy (AFM) and the captive bubble technique revealed that surface roughness and hydrophobicity was similar for both nisin containing multilayers. This suggests that the antimicrobial efficacy of the peptide is unaffected by its location within the multilayer. Overall, these results demonstrate the potential to embed and protect natural antimicrobials within a multilayer to create functionalised coatings that may be desired by industry, such as in the food, biomaterials, and pharmaceutical industry sectors.

Antioxidant Network Based on Sulfonated Polyhydroxyalkanoate and Tannic Acid Derivative

A novel generation of gels based on medium chain length poly(3-hydroxyalkanoate)s, mcl-PHAs, were developed by using ionic interactions. First, water soluble mcl-PHAs containing sulfonate groups were obtained by thiol-ene reaction in the presence of sodium-3-mercapto-1-ethanesulfonate. Anionic PHAs were physically crosslinked by divalent inorganic cations Ca2+, Ba2+, Mg2+ or by ammonium derivatives of gallic acid GA-N(CH3)3 + or tannic acid TA-N(CH3)3 +. The ammonium derivatives were designed through the chemical modification of gallic acid GA or tannic acid TA with glycidyl trimethyl ammonium chloride (GTMA). The results clearly demonstrated that the formation of the networks depends on the nature of the cations. A low viscoelastic network having an elastic around 40 Pa is formed in the presence of Ca2+. Although the gel formation is not possible in the presence of GA-N(CH3)3 +, the mechanical properties increased in the presence of TA-N(CH3)3 + with an elastic modulus G' around 4200 Pa. The PHOSO3 -/TA-N(CH3)3 + gels having antioxidant activity, due to the presence of tannic acid, remained stable for at least 5 months. Thus, the stability of these novel networks based on PHA encourage their use in the development of active biomaterials.

Layer-By-Layer Assemblies of Biopolymers: Build-Up, Mechanical Stability and Molecular Dynamics

Rapid development of versatile layer-by-layer technology has resulted in important breakthroughs in the understanding of the nature of molecular interactions in multilayer assemblies made of polyelectrolytes. Nowadays, polyelectrolyte multilayers (PEM) are considered to be non-equilibrium and highly dynamic structures. High interest in biomedical applications of PEMs has attracted attention to PEMs made of biopolymers. Recent studies suggest that biopolymer dynamics determines the fate and the properties of such PEMs; however, deciphering, predicting and controlling the dynamics of polymers remains a challenge. This review brings together the up-to-date knowledge of the role of molecular dynamics in multilayers assembled from biopolymers. We discuss how molecular dynamics determines the properties of these PEMs from the nano to the macro scale, focusing on its role in PEM formation and non-enzymatic degradation. We summarize the factors allowing the control of molecular dynamics within PEMs, and therefore to tailor polymer multilayers on demand.

Nanoclay-Polyamine Composite Hydrogel for Topical Delivery of Nitric Oxide Gas via Innate Gelation Characteristics of Laponite

Because nitric oxide (NO) gas is an endogenously produced signaling molecule related to numerous physiological functions, manystudies have been conducted to develop NO delivery systems for potential biomedical applications. However, NO is a reactive radical gas molecule that has a very short life-time and readily transforms into nitrogen oxide species via reaction with oxygen species. Therefore, it is necessary to develop an NO delivery carrier that allows local release of the NO gas at the site of application. In this study, Laponite (LP) nanoclay was used to fabricate an NO delivery carrier through the formation of Laponite-polyamine (LP-PAn) composites. The Laponite clay and pentaethylenehexamine (PEHA) formed a macromolecular structure by electrostatic interaction and the nitric oxide donor, N-diazeniumdiolate (NONOates), was synthesized into the LP-PAn composite. We investigated the conformation of the LP-PAn composite structure and the NO donor formation by ζ potential, X-ray diffraction, and UV-vis and Fourier transform infrared (FT-IR) spectroscopies and also by analyzing the NO release profile. Additionally, we confirmed the applicability in biomedical applications via a cell viability and in vitro endothelial cell tube formation assay.