Antibacterial activity of nanofibrous mats coated with lysozyme-layered silicate composites via electrospraying

Perspectives of nanofibrous wound dressings based on glucans and galactans - A review

Wound healing is a complex and dynamic process that needs an appropriate environment to overcome infection and inflammation to progress well. Wounds lead to morbidity, mortality, and a significant economic burden, often due to the non-availability of suitable treatments. Hence, this field has lured the attention of researchers and pharmaceutical industries for decades. As a result, the global wound care market is expected to be 27.8 billion USD by 2026 from 19.3 billion USD in 2021, at a compound annual growth rate (CAGR) of 7.6 %. Wound dressings have emerged as an effective treatment to maintain moisture, protect from pathogens, and impede wound healing. However, synthetic polymer-based dressings fail to comprehensively address optimal and quick regeneration requirements. Natural polymers like glucan and galactan-based carbohydrate dressings have received much attention due to their inherent biocompatibility, biodegradability, inexpensiveness, and natural abundance. Also, nanofibrous mesh supports better proliferation and migration of fibroblasts because of their large surface area and similarity to the extracellular matrix (ECM). Thus, nanostructured dressings derived from glucans and galactans (i.e., chitosan, agar/agarose, pullulan, curdlan, carrageenan, etc.) can overcome the limitations associated with traditional wound dressings. However, they require further development pertaining to the wireless determination of wound bed status and its clinical assessment. The present review intends to provide insight into such carbohydrate-based nanofibrous dressings and their prospects, along with some clinical case studies.

Electrospun fibers as carriers for topical drug delivery and release in skin bandages and patches for atopic dermatitis treatment

The skin is a complex layer system and the most important barrier between the environment and the organism. In this review, we describe some widespread skin problems, with a focus on eczema, which are affecting more and more people all over the world. Most of treatment methods for atopic dermatitis (AD) are focused on increasing skin moisture and protecting from bacterial infection and external irritation. Topical and transdermal treatments have specific requirements for drug delivery. Breathability, flexibility, good mechanical properties, biocompatibility, and efficacy are important for the patches used for skin. Up to today, electrospun fibers are mostly used for wound dressing. Their properties, however, meet the requirements for skin patches for the treatment of AD. Active agents can be incorporated into fibers by blending, coaxial or side-by-side electrospinning, and also by physical absorption post-processing. Drug release from the electrospun membranes is affected by drug and polymer properties and the technique used to combine them into the patch. We describe in detail the in vitro release mechanisms, parameters affecting the drug transport, and their kinetics, including theoretical approaches. In addition, we present the current research on skin patch design. This review summarizes the current extensive know-how on electrospun fibers as skin drug delivery systems, while underlining the advantages in their prospective use as patches for atopic dermatitis. This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Antimicrobial properties of lysozyme in meat and meat products: possibilities and challenges

Meat and meat products are highly perishable as they can provide an appropriate environment for microbial growth due to their high water activity and proper pH level. Quality, safety, sensory and nutritional properties of meat products are highly influenced by pathogenic and spoilage microorganisms. To prevent microbial growth, artificial antimicrobials have been used in food matrices, however safety concerns regarding the use of synthetic preservatives is a challenging issue. Additionally, consumer’s trend towards natural mildly processed products with extended shelf life necessitates the identification of alternative additives originating from natural sources of new acceptable and effective antimicrobials. Although the effectiveness of some natural antimicrobial agents has already been reported, still, there is lack of information regarding the possibility of using lysozyme as a preservative in meat and meat products either alone or in combination with other hurdles. In the present review the applications and beneficial effects of applying lysozyme in meat products, considering its limitations such as allergic problems, interactions with food constituents, reducing sensory changes and toxicity due to high required concentrations to prevent spoilage and oxidation in foods will be discussed

Applications of Lysozyme, an Innate Immune Defense Factor, as an Alternative Antibiotic

Lysozyme is a ~14 kDa protein present in many mucosal secretions (tears, saliva, and mucus) and tissues of animals and plants, and plays an important role in the innate immunity, providing protection against bacteria, viruses, and fungi. Three main different types of lysozymes are known: the c-type (chicken or conventional type), the g-type (goose type), and the i-type (invertebrate type). It has long been the subject of several applications due to its antimicrobial properties. The problem of antibiotic resistance has stimulated the search for new molecules or new applications of known compounds. The use of lysozyme as an alternative antibiotic is the subject of this review, which covers the results published over the past two decades. This review is focused on the applications of lysozyme in medicine, (the treatment of infectious diseases, wound healing, and anti-biofilm), veterinary, feed, food preservation, and crop protection. It is available from a wide range of sources, in addition to the well-known chicken egg white, and its synergism with other compounds, endowed with antimicrobial activity, are also summarized. An overview of the modified lysozyme applications is provided in the form of tables.

Soft materials as biological and artificial membranes

The past few decades have seen emerging growth in the field of soft materials for synthetic biology. This review focuses on soft materials involved in biological and artificial membranes. The biological membranes discussed here are mainly those involved in the structure and function of cells and organelles. As building blocks in medicine, non-native membranes including nanocarriers (NCs), especially liposomes and DQAsomes, and polymeric membranes for scaffolds are constructed from amphiphilic combinations of lipids, proteins, and carbohydrates. Artificial membranes can be prepared using synthetic, soft materials and molecules and then incorporated into structures through self-organization to form micelles or niosomes. The modification of artificial membranes can be realized using traditional chemical methods such as click reactions to target the delivery of NCs and control the release of therapeutics. The biomembrane, a lamellar structure inlaid with ion channels, receptors, lipid rafts, enzymes, and other functional units, separates cells and organelles from the environment. An active domain inserted into the membrane and organelles for energy conversion and cellular communication can target disease by changing the membrane's composition, structure, and fluidity and affecting the on/off status of the membrane gates. The biological membrane targets analyzing pathological mechanisms and curing complex diseases, which inspires us to create NCs with artificial membranes.

Novel PVA-Based Microspheres Co-Loaded with Photothermal Transforming Agent and Chemotherapeutic for Colorectal Cancer Treatment

BACKGROUND

We previously designed an electrospinning chitosan (CS) nanofiber-based carrier, using polyvinyl alcohol (PVA) as an adjuvant to deliver doxorubicin (DOX) and MoS₂ nanosheets for postoperative tumor re-occurrence inhibition. However, owing to that the nanofibrous mat is un-injectable, this composite nanofiber is far from being clinically applicable.

MATERIALS AND METHODS

Via modulating the electrospray parameters, polyvinyl alcohol (PVA) beads string doped with DOX and MoS₂ (PVA/MoS₂/DOX microspheres) were prepared, which were further crosslinked with glutaraldehyde to obtain the water-stability.

RESULTS

Under the 808-nm laser irradiation, MoS₂ nanosheets rendered the prepared PVA/MoS₂/DOX microspheres an excellent light-to-heat conversion performance with η of 23.2%. Besides, the heat generated by near-infrared laser irradiation can improve the effect of chemotherapy by promoting the release rate of DOX. HT29 cell and tumor-bearing nude mice were used to systematically study the combined tumor treatment efficiency of composite nanospheres.

CONCLUSION

PVA/MoS₂/DOX nanospheres have excellent photothermal effect and chemotherapy effect, which can completely suppress the tumor recurrence. Therefore, the PVA/MoS₂/DOX nanospheres are anticipated to find potential applications in the treatment of local colorectal cancer.

Preparation of lysozyme loaded gelatin microcryogels and investigation of their antibacterial properties

Antibacterial micron-sized cryogels, so-called microcryogels, were prepared by cryogelation of gelatin and integration of lysozyme. Gelation yield, specific surface area, macro-porosity and swelling degree of the microcryogels were examined in order to characterize their physical properties. MTT method was utilized to measure cell viability of the gelatin microcryogels with a period of 24, 48, and 72 h and no significant decrease was observed at 72 h. Apoptotic staining assay also showed high viability at 24, 48, 72 h in parallel with the control group. The antibacterial performances of the gelatin microcryogels against Bacillus subtilis, Staphylococcus aureus, and Escherichia coli were examined. The results showed that the incorporation of lysozyme into gelatin microcryogels exhibited the antibacterial activity against S. aureus, B. subtilis, and E. coli, that may provide great potential for various applications in the biomedical industry.

Dual-Functional, Superhydrophobic Coatings with Bacterial Anticontact and Antimicrobial Characteristics

Bacterial pathogens are responsible for millions of cases of illnesses and deaths each year throughout the world. The development of novel surfaces and coatings that effectively inhibit and prevent bacterial attachment, proliferation, and growth is one of the crucial steps for tackling this global challenge. Herein, we report a dual-functional coating for aluminum surfaces that relies on the controlled immobilization of lysozyme enzyme (muramidase) into interstitial spaces of presintered, nanostructured thin film based on ∼200 nm silica nanoparticles and the sequential chemisorption of an organofluorosilane to the available interfacial areas. The mean diameter of the resultant lysozyme microdomains was 3.1 ± 2.5 μm with an average spacing of 8.01 ± 6.8 μm, leading to a surface coverage of 15.32%. The coating had an overall root-mean-square (rms) roughness of 539 ± 137 nm and roughness factor of 1.50 ± 0.1, and demonstrated static, advancing, and receding water contact angles of 159.0 ± 1.0°, 155.4 ± 0.6°, and 154.4 ± 0.6°, respectively. Compared to the planar aluminum, the coated surfaces produced a 6.5 ± 0.1 (>99.99997%) and 4.0 ± 0.1 (>99.99%) log-cycle reductions in bacterial surfaces colonization against Gram-negative Salmonella Typhimurium LT2 and Gram-positive Listeria innocua, respectively. We anticipate that the implementation of such a coating strategy on healthcare environments and surfaces and food-contact surfaces can significantly reduce or eliminate potential risks associated with various contamination and cross-contamination scenarios.

Electrospun Nanocomposites Containing Cellulose and Its Derivatives Modified with Specialized Biomolecules for an Enhanced Wound Healing

Wound healing requires careful, directed, and effective therapies to prevent infections and accelerate tissue regeneration. In light of these demands, active biomolecules with antibacterial properties and/or healing capacities have been functionalized onto nanostructured polymeric dressings and their synergistic effect examined. In this work, various antibiotics, nanoparticles, and natural extract-derived products that were used in association with electrospun nanocomposites containing cellulose, cellulose acetate and different types of nanocellulose (cellulose nanocrystals, cellulose nanofibrils, and bacterial cellulose) have been reviewed. Renewable, natural-origin compounds are gaining more relevance each day as potential alternatives to synthetic materials, since the former undesirable footprints in biomedicine, the environment, and the ecosystems are reaching concerning levels. Therefore, cellulose and its derivatives have been the object of numerous biomedical studies, in which their biocompatibility, biodegradability, and, most importantly, sustainability and abundance, have been determinant. A complete overview of the recently produced cellulose-containing nanofibrous meshes for wound healing applications was provided. Moreover, the current challenges that are faced by cellulose acetate- and nanocellulose-containing wound dressing formulations, processed by electrospinning, were also enumerated.

A Review on Surface-Functionalized Cellulosic Nanostructures as Biocompatible Antibacterial Materials

As the most abundant biopolymer on the earth, cellulose has recently gained significant attention in the development of antibacterial biomaterials. Biodegradability, renewability, strong mechanical properties, tunable aspect ratio, and low density offer tremendous possibilities for the use of cellulose in various fields. Owing to the high number of reactive groups (i.e., hydroxyl groups) on the cellulose surface, it can be readily functionalized with various functional groups, such as aldehydes, carboxylic acids, and amines, leading to diverse properties. In addition, the ease of surface modification of cellulose expands the range of compounds which can be grafted onto its structure, such as proteins, polymers, metal nanoparticles, and antibiotics. There are many studies in which cellulose nano-/microfibrils and nanocrystals are used as a support for antibacterial agents. However, little is known about the relationship between cellulose chemical surface modification and its antibacterial activity or biocompatibility. In this study, we have summarized various techniques for surface modifications of cellulose nanostructures and its derivatives along with their antibacterial and biocompatibility behavior to develop non-leaching and durable antibacterial materials. Despite the high effectiveness of surface-modified cellulosic antibacterial materials, more studies on their mechanism of action, the relationship between their properties and their effectivity, and more in vivo studies are required.

Antimicrobial, microscopic and spectroscopic properties of cellulose paper coated with chitosan sol-gel solution formulated by epsilon-poly-l-lysine and its application in active food packaging

Cellulose paper-chitosan (CC) double-layer films containing epsilon-poly-l-lysine (ε-PL) (0.5 and 1% w/v) were developed. FTIR analysis showed a strong association between the ε-PL and CC film. Antimicrobial activity against Listeria monocytogenes was investigated both in vitro and in the chicken breast meat. The CC films without ε-PL showed no antimicrobial activity, while the addition of ε-PL induced significant (p < 0.05) effects. During the 28 days of storage at 4 ^°C, no significant difference was found on the anti-listeria activity of films. When storage temperature was raised from 4 to 22 ^°C, the antimicrobial activity was reduced. Films containing 1% ε-PL exhibited 1.5 log₁₀ CFU/g reduction in L. monocytogenes population during 12 days storage of meat at 4 ^°C, while no significant reduction was found in CC films with 0.5% ε-PL (p > 0.05). This study revealed an antimicrobial activity for CC films impregnated with ε-PL, to control foodborne pathogens in meat.

Enhancing the antitumor activity of tea polyphenols encapsulated in biodegradable nanogels by macromolecular self-assembly

Nanogels (NGs) with desirable stability have emerged as a promising platform for biomedical applications. Herein, a convenient approach was developed to encapsulate and protect tea polyphenols (TPs) by macromolecular self-assembly of lysozyme (Ly) and carboxymethyl cellulose (CMC) through a heating treatment. Biodegradable Ly–CMC NGs were formed on the basis of molecules driven by electrostatic interaction and hydrophobic forces. The particle size and morphology of the Ly–CMC NGs were analyzed using a Malvern particle size analyzer, fluorescence spectrophotometer, and scanning electron microscope. The results showed that the heated NGs were spherical with better stability and smaller particle size. The encapsulation efficiency of TP-loaded NGs was 89.05 ± 3.14%, and it indicated that the Ly–CMC NGs may have a strong binding force with TPs. Moreover, TP-loaded NGs showed a sustained release feature. The DPPH and ABTS-scavenging rates of the TP-loaded NGs were 76.5% and 86.1%, respectively. The antitumor activity of the TP-loaded NGs can effectively inhibit the proliferation of HepG₂ cells. Furthermore, TP-loaded NGs were proven to significantly enhance the induction of apoptosis in hepatoma cells and exhibit obvious cell cycle arrest. Our results demonstrate that the Ly–CMC NGs have extensive application prospects as a biocompatible and biodegradable delivery carrier of food functional factors to improve their antitumor effects.

Fabrication of biodegradable TP-loaded Ly and CMC nanogels via self-assembly and the study of their controlled release and absorption process in vivo.

Porous structured cellulose microsphere acts as biosensor for glucose detection with "signal-and-color" output

In order to develop a biosensor based on porous structured cellulose microspheres for glucose detection with "signal-and-color" output, in this work, active group carboxyl was introduced to cellulose matrix by using plasma technology, and then glucose oxidase (GOx) was chemically immobilized through EDC-NHS cross-linking reaction. The cellulose microgels containing 21.28 mg/g of enzymes exhibited a fast response to 0.003 M glucose within only 4 min. As for detecting subject with a lower concentration of glucose, the probe still worked. When the concentration of glucose solution was 0.005 M, it took only 2 min that the reaction mixture changed from colorless to yellow. By the introduction of starch, the reaction mixture presented as amaranth color. Besides, the porous-structured substrate and the facile plasma technology were also promising for constructing enzyme-driven catalytic systems with enhanced performance.

Stimuli responsive biopolymer (chitosan) based blend hydrogels for wound healing application

Stimuli responsive chitosan (CS) and poly (N-vinyl-2-pyrrolidone) (PVP) have attained hydrogel properties in the presence of 74% neutralized poly acrylic acid (PAA) which can be exploited for wound healing applications. The FTIR spectra confirmed the presence of all specific functional groups and the developed interactions in the hydrogels. The thermal analysis explained that the hydrogel samples are thermally more stable than individual chitosan and PVP. The antimicrobial analysis revealed that all the samples show antibacterial activity against E. coli and the biodegradation analysis is performed to confirm the hydrogels degradation. The hydrogels showed enhanced responsive swelling behavior against different media depending upon the amount of PVP. The %age swelling in water is decreased with the increase in the amount of PVP. The most considerable swelling behavior is observed against pH, as they manifested low swelling at acidic pH and high swelling at neutral pH while at pH 8, the prominent values are obtained. This distinctive behavior of hydrogels and their biocompatibility made them pertinent to drug delivery and their release profile is examined spectrophotometrically using silver sulfadiazine (antibiotic for burnt wounds) showed 91.2% of drug release for a period of 1 h in phosphate buffer saline (PBS) in a consistent and controlled manner.

Nanocellulose-Based Antibacterial Materials

In recent years, nanocellulose-based antimicrobial materials have attracted a great deal of attention due to their unique and potentially useful features. In this review, several representative types of nanocellulose and modification methods for antimicrobial applications are mainly focused on. Recent literature related with the preparation and applications of nanocellulose-based antimicrobial materials is reviewed. The fabrication of nanocellulose-based antimicrobial materials for wound dressings, drug carriers, and packaging materials is the focus of the research. The most important additives employed in the preparation of nanocellulose-based antimicrobial materials are presented, such as antibiotics, metal, and metal oxide nanoparticles, as well as chitosan. These nanocellulose-based antimicrobial materials can benefit many applications including wound dressings, drug carriers, and packaging materials. Finally, the challenges of industrial production and potentials for development of nanocellulose-based antimicrobial materials are discussed.

Treatment of neurodegenerative disorders through the blood-brain barrier using nanocarriers

Neurodegenerative diseases refer to disorders of the central nervous system (CNS) that are caused by neuronal degradations, dysfunctions, or death. Alzheimer's disease, Parkinson's disease, and Huntington's disease (APHD) are regarded as the three major neurodegenerative diseases. There is a vast body of literature on the causes and treatments of these neurodegenerative diseases. However, the main obstacle in developing an effective treatment strategy is the permeability of the treatment components at the blood-brain barrier (BBB). Several strategies have been developed to improve this obstruction. For example, nanomaterials facilitate drug delivery to the BBB due to their size. They have been used widely in nanomedicine and as nanoprobes for diagnosis purposes among others in neuroscience. Nanomaterials in different forms, such as nanoparticles, nanoemulsions, solid lipid nanoparticles (SLN), and liposomes, have been used to treat neurodegenerative diseases. This review will cover the basic concepts and applications of nanomaterials in the therapy of APHD.

Preparation and study of the antibacterial ability of graphene oxide-catechol hybrid polylactic acid nanofiber mats

The functionalization of electrospun mats with antimicrobial nanomaterials is an attractive strategy when developing functional graphene oxide coating materials to prevent bacterial colonization on surfaces. In this study, we demonstrated a simple approach to produce antimicrobial electrospun mats by dip-coating a polylactic acid (PLA) nanofiber into a graphene oxide-catechol derivative. PLA was first electrospun to yield narrow-diameter polymeric nanofibers. We then modified the graphene oxide (GO) with a catechol derivative - dopamine methacrylamide monomer (DMA) - to synthesize a GO-DMA nanocomposite material which exhibited robust antimicrobial properties. The catechol groups promote the immobilization of graphene oxide onto the PLA nanofibers and possess strong antimicrobial properties. We therefore selected this functional group to modify GO. We dipped the GO-DMA onto the PLA nanofiber to produce the final functionalized electrospun mats. The PLA mats which were functionalized using the GO-DMA nanocomposite (PLA-GO-DMA) displayed antibacterial activity against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria. Furthermore, we studied the biocompatibility of the mats by culturing the cell lines (HepG2, A549, and HUVEC-C) of PLA-GO-DMA among the nanofibers which exhibited excellent biocompatibility. These results collectively demonstrate the potential of PLA-GO-DMA nanofiber mats as antimicrobial biomaterials and provide fundamental information toward the establishment of future biomedical applications.

The effect of graphene-poly(methyl methacrylate) fibres on microbial growth

A novel class of ultra-thin fibres, which affect microbial growth, were explored. The microbial properties of poly(methyl methacrylate) fibres containing 2, 4 and 8 wt% of graphene nanoplatelets (GNPs) were studied. GNPs were dispersed in a polymeric solution and processed using pressurized gyration. Electron microscopy was used to characterize GNP and fibre morphology. Scanning electron microscopy revealed the formation of beaded porous fibres. GNP concentration was found to dictate fibre morphology. As the GNP concentration increased, the average fibre diameter increased from 0.75 to 2.71 µm, while fibre porosity decreased. Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa were used to investigate the properties of 2, 4 and 8 wt% GNP-loaded fibres. GNP-loaded fibres (0 wt%) were used as the negative control. The fibres were incubated for 24 h with the bacteria; bacterial colony-forming units were enumerated by adopting the colony-counting method. The presence of 2 and 4 wt% GNP-loaded fibres promoted microbial growth, while 8 wt% GNP-loaded fibres showed antimicrobial activity. These results indicate that the minimum inhibitory concentration of GNPs required within a fibre is 8 wt%.

Electrospun polymeric nanofibres as wound dressings: A review

Skin wounds have significant morbidity and mortality rates associated. This is explained by the limited effectiveness of the currently available treatments, which in some cases do not allow the reestablishment of the structure and functions of the damaged skin, leading to wound infection and dehydration. These drawbacks may have an impact on the healing process and ultimately prompt patients' death. For this reason, researchers are currently developing new wound dressings that enhance skin regeneration. Among them, electrospun polymeric nanofibres have been regarded as promising tools for improving skin regeneration due to their structural similarity with the extracellular matrix of normal skin, capacity to promote cell growth and proliferation and bactericidal activity as well as suitability to deliver bioactive molecules to the wound site. In this review, an overview of the recent studies concerning the production and evaluation of electrospun polymeric nanofibrous membranes for skin regenerative purposes is provided. Moreover, the current challenges and future perspectives of electrospun nanofibrous membranes suitable for this biomedical application are highlighted.

Polydopamine nanoparticles for the treatment of acute inflammation-induced injury

Nanotechnology-mediated anti-inflammatory therapy is emerging as a novel strategy for the treatment of inflammation-induced injury. However, one of the main hurdles for these anti-inflammatory nano-drugs is their potential toxic side effects in vivo. Herein, we uncovered that polydopamine (PDA) nanoparticles with their structure and chemical properties similar to melanin, a natural bio-polymer, displayed a significant anti-inflammation therapeutic effect on acute inflammation-induced injury. PDA with enriched phenol groups functioned as a radical scavenger to eliminate reactive oxygen species (ROS) generated during inflammatory responses. As revealed by in vivo photoacoustic imaging with a H2O2-specific nanoprobe, PDA nanoparticles remarkably reduced intracellular ROS levels in murine macrophages challenged with either H2O2 or lipopolysaccharide (LPS). The anti-inflammatory capacity of PDA nanoparticles was further demonstrated in murine models of both acute peritonitis and acute lung injury (ALI), where diminished ROS generation, reduced proinflammatory cytokines, attenuated neutrophil infiltration, and alleviated lung tissue damage were observed in PDA-treated mice after a single dose of PDA treatment. Our work therefore presents the great promise of PDA nanoparticles as a biocompatible nano-drug for anti-inflammation therapy to treat acute inflammation-induced injury.

Cellulose-Based Composite Macrogels from Cellulose Fiber and Cellulose Nanofiber as Intestine Delivery Vehicles for Probiotics

Cellulose-based composite macrogels made by cellulose fiber/cellulose nanofiber (CCNM) were used as an intestine delivery vehicle for probiotics. Cellulose nanofiber (CNF) was prepared by a 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation system, and the carboxyl groups in CNF acted as pore size and pH responsibility regulators in CCNMs to regulate the probiotics loading and controlled release property. The macrogel presented a porosity of 92.68% with a CNF content of 90%, and the corresponding released viable Lactobacillus plantarum (L. plantarum) was up to 2.68 × 10⁸ cfu/mL. The porous structure and high porosity benefited L. plantarum cells to infiltrate into the core of macrogels. In addition, the macrogels made with high contents of CNF showed sustainable release of L. plantarum cells and delivered enough viable cells to the desired region of intestine tracts. The porous cellulose macrogels prepared by a green and environmental friendly method show potential in the application of fabricating targeted delivery vehicles of bioactive agents.

Synthesis, antitumor activity and molecular mechanism of doxorubicin conjugated trimethyl-chitosan polymeric micelle loading Beclin1 siRNA for drug-resisted bladder cancer therapy

Herein, we describe a convenient approach for the preparation of a polymeric micelle using doxorubicin (DOX) conjugated trimethyl-chitosan (TMC) with Beclin-1 siRNA (Si-Beclin1/DOX-TMC). This micelle displayed a potent capacity for autophagy inhibition and reversed drug-resistance to DOX in BIU-87/ADR cell lines. The Si-Beclin1/DOX-TMC micelle was highly cytotoxic to both drug-sensitive BIU-87 and drug-resistant BIU-87/ADR cells. Its capacity to reverse drug-resistance was dependent upon upregulation of autophagy levels in BIU-87/ADR cells. DOX was conjugated to TMC via a pH-sensitive Schiff base, which responded to the acidic lysosome microenvironment and resulted in the cytoplasmic release of DOX. The structure of DOX conjugation to the TMC polymeric micelle was characterized by NMR, GPC, TEM and DLS. DOX release profiles in different pH environment were determined by HPLC. Cellular uptake, changes to nuclei morphology and formation of autophagosomes were observed using a fluorescence microscope. Finally, in vivo antitumor activity of systemic Si-Beclin1/DOX-TMC micelle administration was evaluated in BIU-87/ADR xenograft models and Si-Beclin1/DOX-TMC micelles showed significantly suppressed tumor growth.

Herein, we describe a convenient approach for the preparation of a polymeric micelle using doxorubicin (DOX) conjugated trimethyl-chitosan (TMC) with Beclin-1 siRNA (Si-Beclin1/DOX-TMC).

Direct one-pot synthesis of cinnamaldehyde immobilized on gold nanoparticles and their antibiofilm properties

The objective of the present study was to develop a one-pot strategy to synthesis gold nanoparticle complexes using cinnamaldehyde, a potent antibiofilm agent which in its free form, exhibits high volatility and unstable nature. Hence, we developed cinnamaldehyde gold nanoparticles (CGNPs) in a single step to overcome the limitations of free cinnamaldehyde. Furthermore, reduction abilities of cinnamaldehyde under different experimental conditions, that is, varying precursor concentrations of cinnamaldehyde and gold, metal salts, pH, temperature, and light sources, were investigated. UV-vis spectroscopy, transmission electron microscopy, attenuated total reflectance Fourier transform infrared spectroscopy, and dynamic light-scattering measurements revealed that heat influenced the nanoparticle formation in the presence of cinnamaldehyde, and as produced cinnamaldehyde immobilized on gold nanoparticles were spherical, monodispersed, and stable by surface charge. CGNPs containing 0.01% cinnamaldehyde by weight exhibited effective biofilm inhibition of up to >80% against Gram positive bacteria (methicillin-sensitive and -resistant strains of Staphylococcus aureus, MSSA and MRSA, respectively) and Gram negative (Escherichia coli and Pseudomonas aeruginosa) and a fungus Candida albicans. In addition, CGNPs attenuated the virulence of C. albicans by inhibiting hyphae formation. Based on observations of their antibiofilm effects and confocal microscopy findings, CGNPs caused biofilm damage by direct contact. Thus, cinnamaldehyde appears to be a promising reduction material for the eco-friendly, one-pot synthesis of CGNPs with excellent antibiofilm activity.

Small Molecular TGF-β1-Inhibitor-Loaded Electrospun Fibrous Scaffolds for Preventing Hypertrophic Scars

Hypertrophic scarring (HS) is a disorder that occurs during wound healing and seriously depresses the quality of human life. Scar-inhibiting scaffolds, though bringing promise to HS prevention, face problems such as the incompatibility of the scaffold materials and the instability of bioactive molecules. Herein, we present a TGF-β1-inhibitor-doped poly(ε-caprolactone) (PCL)/gelatin (PG) coelectrospun nanofibrous scaffold (PGT) for HS prevention during wound healing. The appropriate ratio of PCL to gelatin can avoid individual defects of the two materials and achieve an optimized mechanical property and biocompatibility. The TGF-β1 inhibitor (SB-525334) is a small molecule and is highly stable during electrospinning and drug release processes. The PGT effectively inhibits fibroblast (the major cell type contributing to scar formation) proliferation in vitro and successfully prevents HS formation during the healing of full-thickness model wounds on rabbit ear. Our strategy offers an excellent solution for potential large-scale production of scaffolds for clinical HS prevention.

Regulating the gaps between folds on the surface of silk fibroin membranes via LBL deposition for improving their biomedical properties

Silk fibroin (SF) has become a promising biomaterial in guided bone regeneration (GBR). In an attempt to modify the size of the gaps on the surface of SF barrier membrane and improve its antibacterial activity, biological and mechanical properties, positively charged Lysozyme (LY)-Collagen Type-I (COL) composites and negatively charged SF were introduced to the negatively charged surface of SF substrates utilizing the electrostatic layer-by-layer (LBL) self-assembly technique. The morphology, chemical structures and element content of the LBL structured membranes were investigated. The results suggested that LY and COL were successfully assembled and the gaps between the folds on the surface of the membranes became smaller gradually with the increase of coated film numbers. Besides, the content of β-sheets of the membranes increased after deposition, which indicated the improvement of their mechanical properties. Moreover, the results of the measurement of immobilized LY and antibacterial assay not only revealed that the enzymatic catalysis and antibacterial activity of the samples enhanced with the increase of coated bilayer numbers but also implied that LBL modified membranes had better antibacterial activity when LY-COL was on the outermost layer. Furthermore, CCK-8 assay certified both SF membrane and LBL structured membranes could facilitate cell growth and proliferation, and the introduction of COL could further promote this ability. Finally, cell attachment and morphology examination provided intuitional evidence that SF membrane and LBL modified membranes have excellent biocompatibility.

In vivo safety and efficacy of sericin/poly(vinyl alcohol)/glycerin scaffolds fabricated by freeze-drying and salt-leaching techniques for wound dressing applications

In our previous works, two techniques (freeze-drying and salt-leaching) were introduced to fabricate the sericin/poly(vinyl alcohol)/glycerin scaffolds. The freeze-dried and salt-leached sericin/poly(vinyl alcohol)/glycerin scaffolds with the same composition showed distinguished physical and in vitro biological characteristics. In this study, the in vivo safety and efficacy tests of both scaffolds as dressing materials for the healing of full-thickness wounds in rat model were performed in comparison with the clinically used dressing, Allevyn®. In the safety test, the scaffolds were implanted subcutaneously, and the signs of tissue irritation including the extent of inflammatory cells, calcification, vascularization, and fatty infiltration were scored. In the efficacy test, the scaffolds were applied to the full-thickness wound (1.5 cm × 1.5 cm), and the epithelialization and collagen formation in the wound were evaluated. Both freeze-dried and salt-leached scaffolds were characterized as non- to slightly irritant implantable materials. The freeze-dried scaffold minimally causes irritation to the tissue possibly because it was derived from the non-chemical relevant process. Furthermore, the freeze-dried scaffold showed the highest wound healing efficiency as characterized by the fastest epithelialization and highest extent of collagen formation. This might be due to the more sustained release of sericin from the freeze-dried scaffold, compared to that of the salt-leached scaffold. Therefore, fabrication process seemed to directly regulate the properties and applicability of the scaffolds. The safety and efficacy of the dressing materials in wound healing application depended not only on the materials themselves but also on the fabrication process that produces them.

Enhancement of the antimicrobial activity of cinnamon essential oil-loaded electrospun nanofilm by the incorporation of lysozyme

The antimicrobial activity of cinnamon essential oil-based electrospun nanofilm is enhanced by the combination of lysozyme.

Cationic amphiphile in phospholipid bilayer or oil-water interface of nanocarriers affects planktonic and biofilm bacteria killing

A cationic amphiphile, soyaethyl morpholinium ethosulfate (SME), immobilized in liposomes or nanoemulsions, was prepared in an attempt to compare the antibacterial activity between SME intercalated in the phospholipid bilayer and oil-water interface. Before antibacterial assessment, the size of the liposomes and nanoemulsions was respectively recorded as 75 and 214 nm. The data of minimum inhibitory concentration (MIC)/minimum bactericidal concentration (MBC) and live/dead cell count demonstrated a superior antimicrobial activity of nanoemulsions compared to liposomes against Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), and Staphylococcus epidermidis. Nanoemulsion incubation reduced biofilm thickness by 2.4-fold, whereas liposomes showed a 1.6-fold decrease in thickness. SME insertion in the oil-water phase was found to induce bacterial membrane disruption. SME nanosystems were nontoxic to keratinocytes. In vivo topical application of the cationic nanosystems reduced skin infection, MRSA load, and inflammation in mice. The deteriorated skin barrier function evoked by MRSA was recovered by nanoemulsion treatment.

Porous Cellulose Microgel Particle: A Fascinating Host for the Encapsulation, Protection, and Delivery of Lactobacillus plantarum

Advances in probiotic markets are always restrained by a low viable loading capacity and poor viability. Herein, cellulose microgels (CMs) with high porosity of 95.83 ± 0.38%, prepared by the sol-gel transition method, turned out to be a hospitable host that accommodated a large number of viable Lactobacillus plantarum higher than 10(9) colony-forming units (cfu)/g. The unique porous structure fascinated probiotics to penetrate into the core of microgels. The conjugation with alginate helped for better acid resistance and bacterial survival of the probiotics. In comparison to Ca-alginate gels, core-shell gels showed sustainable release of L. plantarum cells without damage of viability, lasting for 360 min in simulated intestine fluid. The cellulose host helped to sustain the viable cell release for a longer duration and afford better shelter for L. plantarum cells as a result of the porous structure and rigid supporting property. The core-shell gels are promising for constructing targeted delivery vehicles of bioactive nutrients.