Design of Experiment, Preparation, and in vitro Biological Assessment of Human Amniotic Membrane Extract Loaded Nanoparticles

In silico design and mechanistic study of niosome-encapsulated curcumin against multidrug-resistant Staphylococcus aureus biofilms

Curcumin, an important natural component of turmeric, has been known for a long time for its antimicrobial properties. This study aimed to investigate the anti-biofilm action of the niosome-encapsulated curcumin and explore the involved anti-biofilm mechanism. In silico investigations of ADME-Tox (absorption, distribution, metabolism, excretion, and toxicity) were first performed to predict the suitability of curcumin for pharmaceutical application. Curcumin showed low toxicity but at the same time, low solubility and low stability, which, in turn, might reduce its antimicrobial activity. To overcome these intrinsic limitations, curcumin was encapsulated using a biocompatible niosome system, and an encapsulation efficiency of 97% was achieved. The synthesized curcumin-containing niosomes had a spherical morphology with an average diameter of 178 nm. The niosomal curcumin was capable of reducing multi-drug resistant (MDR) Staphylococcus aureus biofilm 2-4-fold compared with the free curcumin. The encapsulated curcumin also demonstrated no significant cytotoxicity on the human foreskin fibroblasts. To understand the interaction between curcumin and S. aureus biofilm, several biofilm-related genes were analyzed for their expression. N-acetylglucosaminyl transferase (IcaD), a protein involved in the production of polysaccharide intercellular adhesion and known to play a function in biofilm development, was found to be downregulated by niosomal curcumin and showed high binding affinity (-8.3 kcal/mol) with curcumin based on molecular docking analysis. Our study suggests that the niosome-encapsulated curcumin is a promising approach for the treatment of MDR S. aureus biofilm and can be extended to biofilms caused by other pathogens.

Encapsulation of Thymol in Gelatin Methacryloyl (GelMa)-Based Nanoniosome Enables Enhanced Antibiofilm Activity and Wound Healing

Non-healing wounds impose huge cost on patients, healthcare, and society, which are further fortified by biofilm formation and antimicrobial resistance (AMR) problems. Here, Thymol, an herbal antimicrobial agent, is utilized to combat AMR. For efficient delivery of Thymol gelatin methacryloyl (GelMa), a hydrophilic polymeric hydrogel with excellent biocompatibility combined with niosome was used to encapsulate Thymol. After optimization of the niosomal Thymol (Nio-Thymol) in the company of GelMa (Nio-Thymol@GelMa) to achieve maximum entrapment efficiency, minimum size, and low polydispersity index, the Thymol release peaked at 60% and 42% from Nio-Thymol@GelMa in medium with pH values of 6.5 and 7.4 after 72 h, respectively. Furthermore, Nio-Thymol@GelMa demonstrated higher antibacterial and anti-biofilm activity than Nio-Thymol and free Thymol against both Gram-negative and Gram-positive bacteria. Interestingly, compared with other obtained formulations, Nio-Thymol@GelMa also led to greater enhancement of migration of human dermal fibroblasts in vitro, and higher upregulation of the expression of certain growth factors such as FGF-1, and matrix metalloproteinases such as MMP-2 and MMP-13. These results suggest that Nio-Thymol@GelMa can represent a potential drug preparation for Thymol to enhance the wound healing process and antibacterial efficacy.

Human amniotic membrane as a multifunctional biomaterial: recent advances and applications

The developing fetus is wrapped by a human amniotic membrane or amnion. Amnion is a promising human tissue allograft in clinical application because of its chemical composition, collagen-based, and mechanical properties of the extracellular matrix. In addition, amnion contains cells and growth factors; therefore, meets the essential parameters of tissue engineering. No donor morbidity, easy processing and storage, fewer ethical issue, anti-inflammatory, antioxidant, antibacterial, and non-immunogenic properties are other advantages of amnion usage. For these reasons, amnion can resolve some bottlenecks in the regenerative medicine issues such as tissue engineering and cell therapy. Over the last decades, biomedical applications of amnion have evolved from a simple sheet for skin or cornea repair to high-technology applications such as amnion nanocomposite, powder, or hydrogel for the regeneration of cartilage, muscle, tendon, and heart. Furthermore, amnion has anticancer as well as drug/cell delivery capacity. This review highlights various ancient and new applications of amnion in research and clinical applications, from regenerative medicine to cancer therapy, focusing on articles published during the last decade that also revealed information regarding amnion-based products. Challenges and future perspectives of the amnion in regenerative medicine are also discussed.

Streptomycin Sulfate-Loaded Niosomes Enables Increased Antimicrobial and Anti-Biofilm Activities

One of the antibiotics used to treat infections is streptomycin sulfate that inhibits both Gram-negative and -positive bacteria. Nanoparticles are suitable carriers for the direct delivery and release of drug agents to infected locations. Niosomes are one of the new drug delivery systems that have received much attention today due to their excellent biofilm penetration property and controlled release. In this study, niosomes containing streptomycin sulfate were prepared by using the thin layer hydration method and optimized based on the size, polydispersity index (PDI), and encapsulation efficiency (EE%) characteristics. It was found that the Span 60-to-Tween 60 ratio of 1.5 and the surfactant-to-cholesterol ratio of 1.02 led to an optimum formulation with a minimum of size, low PDI, and maximum of EE of 97.8 nm, 0.27, and 86.7%, respectively. The drug release investigation showed that 50.0 ± 1.2% of streptomycin sulfate was released from the niosome in 24 h and reached 66.4 ± 1.3% by the end of 72 h. Two-month stability studies at 25° and 4°C showed more acceptable stability of samples kept at 4°C. Consequently, antimicrobial and anti-biofilm activities of streptomycin sulfate-loaded niosomes against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa were found significantly higher than those of free drug, and the minimum inhibitory concentration values decreased 4- to 8-fold. Furthermore, niosome-encapsulated streptomycin up to 1,500 μg/ml exhibited negligible cytotoxicity against the human foreskin fibroblasts cell line, whereas the free drug exhibited slight cytotoxicity at this concentration. Desired physical characteristics and low toxicity of niosomal nano-carriers containing streptomycin sulfate made them a demanded candidate for the treatment of current bacterial infections and biofilms.

A Review on Modifications of Amniotic Membrane for Biomedical Applications

The amniotic membrane (AM) is the innermost layer of the fetal placenta, which surrounds and protects the fetus. Its unique structure, in addition to its physical and biological properties, makes it a useful substance in many applications related to regenerative medicine. The use of this fantastic substance with a century-old history has produced remarkable results in vivo, in vitro, and even in clinical studies. While the intact or preserved AM is widely used for these purposes, the addition of further modifications to AM can be considered as a relatively new subject in its applications. These modifications are applied to improve AM properties, ease of handling, and durability. Here, we will discuss the cases in which AM has undergone additional modifications besides the required processes for sterilization and preservation. In this article, we have categorized these modifications and discussed their applications and results.

Biocompatibility improvement of artificial cornea using chitosan-dextran nanoparticles containing bioactive macromolecules obtained from human amniotic membrane

Corneal transplantation, by which the damaged cornea is replaced by a new one, suffers from limited access to HLA-compatible-donors and high maintenance and surgical costs. Therefore, artificial corneas are considered as alternative tools with promising prospects. In our previous study, a two-part-polymeric artificial cornea was composed of enhanced hydrophilic surface electrospun poly(ε-caprolactone) nanofibrous scaffold that is thermally connected to a polyvinyl alcohol-based hydrogel disk was prepared. Characterization tests revealed the prepared artificial cornea had similar biocompatible and structural characteristics regarding the natural cornea. In current study, human amniotic membrane extract containing growth factors, cytokines, anti-inflammatory factors, and anti-angiogenic factors was prepared, nano-encapsulated in chitosan-dextran nanoparticles, and physically decorated on the poly(ε-caprolactone)-polyvinyl-alcohol artificial cornea. Physicochemical and biological characterizations revealed the nano-decorated artificial cornea has more biocompatibility than the unmodified one. Our study demonstrated the bioactive macromolecules loaded on chitosan-dextran nanoparticles enhanced the anti-angiogenic property of artificial cornea through the sustained release of anti-angiogenic factors such as thrombospondin-1, endostatin, and heparin sulfate proteoglycan. Real-time-PCR and flow-cytometry assessments elucidated the vascularization was inhibited through a decrease in the expression of cluster of differentiation 31 and von-Willebrand-Factor. Our study proposed the use of biocompatible artificial cornea could be a promising strategy in corneal transplantation.

Optimization, physicochemical characterization, and antimicrobial activity of a novel simvastatin nano-niosomal gel against E. coli and S. aureus

Niosomes, as a kind of drug delivery system, is widely used for the topical delivery of lipophilic drugs. Optimization of niosomes plays an essential role in enhancing their therapeutic efficiencies. This study aims to prepare an optimized niosomal formulation of simvastatin (nSIM), a lipophilic member of statins, through the experiment (Response Surface methodology). Optimized niosomes were characterized in size, polydispersity index (PDI), entrapment efficiency (EE), stability, releasing pattern, and antimicrobial activity. The different molar ratio of surfactant and cholesterol were applied to prepare various formulation of simvastatin loaded niosome. Mean particle size and size distribution were analyzed by dynamic light scattering. Antibacterial activity was determined by MIC and MBC tests against Staphylococcus aureus and Escherichia coli. The release rate of simvastatin from noisome nanoparticles was studied by the Franz diffusion cell method. The release pattern was studied through zero order, first order, Higuchi, Korsmeyer-Peppas, and Hixson-Crowell kinetics models. Optimized niosomes were obtained by span 80, drug to cholesterol ratio of 0.4 with 7 min sonication time. Mean particle size, PDI, zeta potential, and entrapment efficiency (EE%) of optimized nSIM were obtained about 168 nm, 0.34, -32.40, and 96 %, respectively. The niosomes significantly decreased the drug's releasing rate and enhanced antibacterial activity against S. aureus and E. Coli. It was found that the release pattern of drug followed the Higuchi kinetic model which means drug release is by diffusion. Overall, our findings indicated that the prepared simvastatin loaded niosomes showed good stability and biological properties than free drug. Our study suggests that niosomal formulation could be considered as a promising strategy for the delivery of poor water-soluble drugs that enhance antibacterial activity.