Non-invasive and probeless rapid in-vitro monitoring and quantification of HUVECs counts based on FFT impedimetery.

Introduction: The endothelial cells derived from the human vein cord (HUVECs) are used as in-vitro models for studying cellular and molecular pathophysiology, drug and hormones transport mechanisms, or pathways. In these studies, the proliferation and quantity of cells are important features that should be monitored and assessed regularly. So rapid, easy, noninvasive, and inexpensive methods are favorable for this purpose. Methods: In this work, a novel method based on fast Fourier transform square-wave voltammetry (FFTSWV) combined with a 3D printed electrochemical cell including two inserted platinum electrodes was developed for non-invasive and probeless rapid in-vitro monitoring and quantification of human umbilical vein endothelial cells (HUVECs). The electrochemical cell configuration, along with inverted microscope images, provided the capability of easy use, online in-vitro monitoring, and quantification of the cells during proliferation. Results: HUVECs were cultured and proliferated at defined experimental conditions, and standard cell counts in the initial range of 12 500 to 175 000 were prepared and calibrated by using a hemocytometer (Neubauer chamber) counting for electrochemical measurements. The optimum condition, for FFTSWV at a frequency of 100 Hz and 5 mV amplitude, were found to be a safe electrochemical measurement in the cell culture medium. In each run, the impedance or admittance measurement was measured in a 5 seconds time window. The total measurements were fulfilled at 5, 24, and 48 hours after the seeding of the cells, respectively. The recorded microscopic images before every electrochemical assay showed the conformity of morphology and objective counts of cells in every plate well. The proposed electrochemical method showed dynamic linearity in the range of 12 500-265 000 HUVECs 48 hours after the seeding of cells. Conclusion: The proposed electrochemical method can be used as a simple, fast, and noninvasive technique for tracing and monitoring of HUVECs population in in-vitro studies. This method is highly cheap in comparison with other traditional tools. The introduced configuration has the versatility to develop electrodes for the study of various cells and the application of other electrochemical designations.

Nanocarrier-based gene delivery for immune cell engineering.

Clinical advances in genetically modified immune cell therapies, such as chimeric antigen receptor T cell therapies, have raised hope for cancer treatment. The majority of these biotechnologies are based on viral methods for ex vivo genetic modification of the immune cells, while the non-viral methods are still in the developmental phase. Nanocarriers have been emerging as materials of choice for gene delivery to immune cells. This is due to their versatile physicochemical properties such as large surface area and size that can be optimized to overcome several practical barriers to successful gene delivery. The in vivo nanocarrier-based gene delivery can revolutionize cell-based cancer immunotherapies by replacing the current expensive autologous cell manufacturing with an off-the-shelf biomaterial-based platform. The aim of this research is to review current advances and strategies to overcome the challenges in nanoparticle-based gene delivery and their impact on the efficiency, safety, and specificity of the process. The main focus is on polymeric and lipid-based nanocarriers, and their recent preclinical applications for cancer immunotherapy.

Co-electrospun PCL-collagen nanofibers containing saffron-synthesized gold nanoparticles as an antioxidant wound dressing.

Oxidant environment and inflammation are the leading cause of chronic wounds such as diabetic ulcers. A dressing containing antioxidants would ensure accelerated wound healing. In this study, electrospun gold nanoparticle (GNP)-embedded nanofibers were developed. GNPs (about 7 nm) were synthesized using saffron extract as a reducing and capping agent (GNP-EXT). For comparison, nanoparticles of the same size were also synthesized using citrate (GNP-CIT). Nanoparticle colloids showed a zeta potential of -27 mV. FTIR confirmed the presence of the extract molecules on the nanoparticles. DPPH assay demonstrated the significant radical scavenging properties of the GNP-EXT. The effect of nanoparticles on the viability of NIH3T3 mouse fibroblast cells was evaluated with an MTT assay that showed no significant toxicity of nanoparticles even in the highest concentration of 250 ppm. Then poly (ɛ-caprolactone) (PCL)- Collagen nanofibers containing GNPs were electrospun. By using SEM, TEM, ATR-FTIR, and contact angle measurement, the nanofibers were characterized. Proper cell adhesion and spreading was observed on nanofibers by SEM and Alamar blue assay illustrated appropriate cyto-compatibility on the obtained nanofibers after 5 days of cell seeding. Wound healing assay also confirmed the cell supporting properties and biocompatibility. The results suggest that saffron-synthesized GNP-loaded nanofibers would be considered as potential wound dressings.

Development of a High Sensitive Multiplex Lateral Flow Immunoassay (LFIA) System for Rapid Detection of Methicillin-Resistant Staphylococcus Aureus (MRSA).

Background: Methicillin-resistant Staphylococcus aureus (MRSA) has become a worldwide concern as an epidemic bacterium and a cause of nosocomial and community-acquired infections. One of the major problems in the prevention and treatment of infections caused by MRSA strains is their multi-drug resistant trait, which causes the spread of infections and increases the mortality rate. Therefore, a rapid and accurate method is needed to identify MRSA strains, initiate appropriate antibiotic therapy, and control its infection. The aim of this study was to develop a twin lateral flow immunoassay system to detect methicillin-resistant Staphylococcus aureus (MRSA). Methods: First, BSA blocked AuNPs-anti-peptidoglycan antibody and AuNPs-anti-BSA antibody were used to detect Staphylococcus aureus (S. aureus). Then, AuNPs-anti-PBP2a antibody was used to specifically detect MRSA. Sensitivity, specificity and limit of detection of this twin immunoassay system were assessed using MRSA, methicillin susceptible S. aureus and clinical samples. Results were compared to those of cefoxitin disc diffusion (FOX30) and Polymerase Chain Reaction (PCR) as gold standards. Results: The Limit of Detection (LOD) of this twin system were 103 and 104 CFU/ml for the first and second strips, respectively. Sensitivity and specificity of this innovative assay in detecting MRSA were 92.30 and 97.36%, compared to FOX30 and PCR, respectively. Conclusion: High rates of sensitivity and specificity of this initiative system show its high potentials for rapid and accurate detection of MRSA.

Cell-based wound dressing: Bilayered PCL/gelatin nanofibers-alginate/collagen hydrogel scaffold loaded with mesenchymal stem cells.

Wound dressing is applied to promote the healing process, wound protection, and additionally regeneration of injured skin. In this study, a bilayer scaffold composed of a hydrogel and nanofibers was fabricated to improve the regeneration of injured skin. To this end, polycaprolactone/gelatin (PCL/Gel) nanofibers were electrospun directly on the prepared collagen/alginate (Col/Alg) hydrogel. The bilayer scaffold was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), mechanical properties, and swelling/degradation time. Cytotoxicity assays were evaluated using MTT assay. Then, the nanofiber and bilayer scaffolds were seeded with Adipose-derived stem cells (ADSCs). ADSCs were isolated from rat adipose tissue and analyzed using flow cytometry, in advance. Full-thickness wounds on the backs of rats were dressed with ADSCs-seeded bilayer scaffolds and nanofibers. Histopathological evaluations were performed after 14 and 21 days using H&E (hematoxylin and eosin) staining. The results indicated that re-epithelialization, angiogenesis, and collagen remodeling were enhanced in ADSCs-seeded bilayer scaffolds and nanofibers in comparison with the control group. In conclusion, the best re-epithelialization, collagen organization, neovascularization, and low presence of inflammation in the wound area were observed in the ADSCs-seeded bilayer scaffolds.

Nanofibers in Respiratory Masks: An Alternative to Prevent Pathogen Transmission.

Recent global outbreak of COVID-19 has raised serious awareness about our abilities to protect ourselves from hazardous pathogens and volatile organic compounds. Evidence suggests that personal protection equipment such as respiratory masks can radically decrease rates of transmission and infections due to contagious pathogens. To increase filtration efficiency without compromising breathability, application of nanofibers in production of respiratory masks have been proposed. The emergence of nanofibers in the industry has since introduced a next generation of respiratory masks that promises improved filtration efficiency and breathability via nanometric pores and thin fiber thickness. In addition, the surface of nanofibers can be functionalized and enhanced to capture specific particles. In addition to conventional techniques such as melt-blown, respiratory masks by nanofibers have provided an opportunity to prevent pathogen transmission. As the surge in global demand for respiratory masks increases, herein, we reviewed recent advancement of nanofibers as an alternative technique to be used in respiratory mask production.

Gene therapy to enhance angiogenesis in chronic wounds.

Skin injuries and chronic non-healing wounds are one of the major global burdens on the healthcare systems worldwide due to their difficult-to-treat nature, associated co-morbidities, and high health care costs. Angiogenesis has a pivotal role in the wound-healing process, which becomes impaired in many chronic non-healing wounds, leading to several healing disorders and complications. Therefore, induction or promotion of angiogenesis can be considered a promising approach for healing of chronic wounds. Gene therapy is one of the most promising upcoming strategies for the treatment of chronic wounds. It can be classified into three main approaches: gene augmentation, gene silencing, and gene editing. Despite the increasing number of encouraging results obtained using nucleic acids (NAs) as active pharmaceutical ingredients of gene therapy, efficient delivery of NAs to their site of action (cytoplasm or nucleus) remains a key challenge. Selection of the right therapeutic cargo and delivery methods is crucial for a favorable prognosis of the healing process. This article presents an overview of gene therapy and non-viral delivery methods for angiogenesis induction in chronic wounds.

Macrophages as a therapeutic target to promote diabetic wound healing.

It is well established that macrophages are key regulators of wound healing, displaying impressive plasticity and an evolving phenotype, from an aggressive pro-inflammatory or "M1" phenotype to a pro-healing or "M2" phenotype, depending on the wound healing stage, to ensure proper healing. Because dysregulated macrophage responses have been linked to impaired healing of diabetic wounds, macrophages are being considered as a therapeutic target for improved wound healing. In this review, we first discuss the role of macrophages in a normal skin wound healing process and discuss the aberrations that occur in macrophages under diabetic conditions. Next we provide an overview of recent macrophage-based therapeutic approaches, including delivery of ex-vivo-activated macrophages and delivery of pharmacological strategies aimed at eliminating or re-educating local skin macrophages. In particular, we focus on strategies to silence key regulator genes to repolarize wound macrophages to the M2 phenotype, and we provide a discussion of their potential future clinical translation.

Decontamination Assessment of Nanofiber-based N95 Masks.

As the world battles with the outbreak of the novel coronavirus, it also prepares for future global pandemics that threaten our health, economy, and survivor. During the outbreak, it became evident that use of personal protective equipment (PPE), specially face masks, can significantly slow the otherwise uncontrolled spread of the virus. Nevertheless, the outbreak and its new variants have caused shortage of PPE in many regions of the world. In addition, waste management of the enormous economical and environmental footprint of single use PPE has proven to be a challenge. Therefore, this study advances the theme of decontaminating used masks. More specifically, the effect of various decontamination techniques on the integrity and functionality of nanofiber-based N95 masks (i.e. capable of at least filtering 95% of 0.3 µm aerosols) were examined. These techniques include 70% ethanol, bleaching, boiling, steaming, ironing as well as placement in autoclave, oven, and exposure to microwave (MW) and ultraviolet (UV) light. Herein, filtration efficiency (by Particle Filtration Efficiency equipment), general morphology, and microstructure of nanofibers (by Field Emission Scanning Electron microscopy) prior and after every decontamination technique were observed. The results suggest that decontamination of masks with 70% ethanol can lead to significant unfavorable changes in the microstructure and filtration efficiency (down to 57.33%) of the masks. In other techniques such as bleaching, boiling, steaming, ironing and placement in the oven, filtration efficiency dropped to only about 80% and in addition, some morphological changes in the nanofiber microstructure were seen. Expectedly, there was no significant reduction in filtration efficiency nor microstructural changes in the case of placement in autoclave and exposure to the UV light. It was concluded that, the latter methods are preferable to decontaminate nanofiber-based N95 masks.

Hybrid PCL/chitosan-PEO nanofibrous scaffolds incorporated with A. euchroma extract for skin tissue engineering application.

Skin tissue engineering is an advanced method to repair and regenerate skin injuries. Recent research is focused on the development of scaffolds that are safe, bioactive, and cytocompatible. In this work, a new hybrid nanofibrous scaffold composed of polycaprolactone/chitosan-polyethylene oxide (PCL/Cs-PEO) incorporated with Arnebia euchroma (A. euchroma) extract were synthesized by the two-nozzle electrospinning method. Then the synthesized scaffold was characterized for morphology, sustainability, chemical structure and properties. Moreover, to verify their potential in the burn wound healing process, biodegradation rate, contact angle, swelling properties, water vapor permeability, mechanical properties, antibacterial activity and drug release profile were measured. Furthermore, cytotoxicity and biocompatibility tests were performed on human dermal fibroblasts cell line via XTT and LDH assay. It is shown that the scaffold improved and increased proliferation during in-vitro studies. Thus, results confirm the efficacy and potential of the hybrid nanofibrous scaffold for skin tissue engineering.

Macrophage reprogramming into a pro-healing phenotype by siRNA delivered with LBL assembled nanocomplexes for wound healing applications.

Excessive inflammatory responses in wounds are characterized by the presence of high levels of pro-inflammatory M1 macrophages rather than pro-healing M2 macrophages, which leads to delayed wound healing. Macrophage reprogramming from the M1 to M2 phenotype through knockdown of interferon regulatory factor 5 (irf5) has emerged as a possible therapeutic strategy. While downregulation of irf5 could be achieved by siRNA, it very much depends on successful intracellular delivery by suitable siRNA carriers. Here, we report on highly stable selenium-based layer-by-layer (LBL) nanocomplexes (NCs) for siRNA delivery with polyethyleneimine (PEI-LBL-NCs) as the final polymer layer. PEI-LBL-NCs showed good protection of siRNA with only 40% siRNA release in a buffer of pH = 8.5 after 72 h or in simulated wound fluid after 4 h. PEI-LBL-NCs also proved to be able to transfect RAW 264.7 cells with irf5-siRNA, resulting in successful reprogramming to the M2 phenotype as evidenced by a 3.4 and 2.6 times decrease in NOS-2 and TNF-α mRNA expression levels, respectively. Moreover, irf5-siRNA transfected cells exhibited a 2.5 times increase of the healing mediator Arg-1 and a 64% increase in expression of the M2 cell surface marker CD206+. Incubation of fibroblast cells with conditioned medium isolated from irf5-siRNA transfected RAW 264.7 cells resulted in accelerated wound healing in an in vitro scratch assay. These results show that irf5-siRNA loaded PEI-LBL-NCs are a promising therapeutic approach to tune macrophage polarization for improved wound healing.

Increasing Angiogenesis Factors in Hypoxic Diabetic Wound Conditions by siRNA Delivery: Additive Effect of LbL-Gold Nanocarriers and Desloratadine-Induced Lysosomal Escape.

Impaired wound healing in people with diabetes has multifactorial causes, with insufficient neovascularization being one of the most important. Hypoxia-inducible factor-1 (HIF-1) plays a central role in the hypoxia-induced response by activating angiogenesis factors. As its activity is under precise regulatory control of prolyl-hydroxylase domain 2 (PHD-2), downregulation of PHD-2 by small interfering RNA (siRNA) could stabilize HIF-1α and, therefore, upregulate the expression of pro-angiogenic factors as well. Intracellular delivery of siRNA can be achieved with nanocarriers that must fulfill several requirements, including high stability, low toxicity, and high transfection efficiency. Here, we designed and compared the performance of layer-by-layer self-assembled siRNA-loaded gold nanoparticles with two different outer layers-Chitosan (AuNP@CS) and Poly L-arginine (AuNP@PLA). Although both formulations have exactly the same core, we find that a PLA outer layer improves the endosomal escape of siRNA, and therefore, transfection efficiency, after endocytic uptake in NIH-3T3 cells. Furthermore, we found that endosomal escape of AuNP@PLA could be improved further when cells were additionally treated with desloratadine, thus outperforming commercial reagents such as Lipofectamine® and jetPRIME®. AuNP@PLA in combination with desloratadine was proven to induce PHD-2 silencing in fibroblasts, allowing upregulation of pro-angiogenic pathways. This finding in an in vitro context constitutes a first step towards improving diabetic wound healing with siRNA therapy.

pH-Sensitive PEGylated Liposomal Silybin: Synthesis, In Vitro and In Vivo Anti-Tumor Evaluation.

The drug delivery systems improve the efficacy of chemotherapeutics through enhanced targeting and controlled release however, biological barriers of tumor microenvironment greatly impede the penetration of nanomedicine within the tumor. We report herein the fabrication of a PEG-detachable silybin (SLB) pH-sensitive liposome decorated with TAT-peptide. For this, Acyl hydrazide-activated PEG2000 was prepared and linked with ketone-derivatized DPPE via an acid-labile hydrazone bond to form mPEG2000-HZ-DPPE. TAT peptide was conjugated with a shorter -PEG1000-DSPE spacer and post-inserted into PEGylated liposome (DPPC: mPEG2000-DSPE: Chol). To prepare nanoliposomes (around 100 nm), first, a novel method was used to prepare SLB-Soya PC (SLB-SPC) complex, then this complex was incorporated into nanoliposomes. The pH-sensitivity and shielding effect of long PEG chain on TAT peptide was investigated using DiI liposome and FACS analysis. Pre-treatment to the lowered pH enhanced cellular association of TAT-modified pH-sensitive liposome due to the cleavage of hydrazone bond and TAT exposure. Besides, TAT-modified pH-sensitive liposomes significantly reduced cell viability compared to the plain liposome. In vivo results were very promising with pH-sensitive liposome by detaching PEG moieties upon exposure to the acidic tumor microenvironment, enhancing cellular uptake, retarding tumor growth, and prolonging the survival of 4T1 breast tumor-bearing BALB/c mice. TAT modification of pH-sensitive liposome improved cancer cell association and cytotoxicity and demonstrated potential intracellular delivery upon exposure to acidic pH. However, in in vivo studies, TAT as a targeting ligand significantly decreased the therapeutic efficacy of the formulation attributed to an inefficient tumor accumulation and higher release rate in the circulation. The results of this study indicated that pH-sensitive liposome containing SLB, which was prepared with a novel method with a significant SLB loading efficiency, is very effective in the treatment of 4T1 breast tumor-bearing BALB/c mice and merits further investigation.

Enhanced siRNA Delivery and Selective Apoptosis Induction in H1299 Cancer Cells by Layer-by-Layer-Assembled Se Nanocomplexes: Toward More Efficient Cancer Therapy.

Nanotechnology has made an important contribution to oncology in recent years, especially for drug delivery. While many different nano-delivery systems have been suggested for cancer therapy, selenium nanoparticles (SeNPs) are particularly promising anticancer drug carriers as their core material offers interesting synergistic effects to cancer cells. Se compounds can exert cytotoxic effects by acting as pro-oxidants that alter cellular redox homeostasis, eventually leading to apoptosis induction in many kinds of cancer cells. Herein, we report on the design and synthesis of novel layer-by-layer Se-based nanocomplexes (LBL-Se-NCs) as carriers of small interfering RNA (siRNA) for combined gene silencing and apoptosis induction in cancer cells. The LBL-Se-NCs were prepared using a straightforward electrostatic assembly of siRNA and chitosan (CS) on the solid core of the SeNP. In this study, we started by investigating the colloidal stability and protection of the complexed siRNA. The results show that CS not only functioned as an anchoring layer for siRNA, but also provided colloidal stability for at least 20 days in different media when CS was applied as a third layer. The release study revealed that siRNA remained better associated with LBL-Se-NCs, with only a release of 35% after 7 days, as compared to CS-NCs with a siRNA release of 100% after 48 h, making the LBL nanocarrier an excellent candidate as an off-the-shelf formulation. When applied to H1299 cells, it was found that they can selectively induce around 32% apoptosis, while significantly less apoptosis (5.6%) was induced in NIH/3T3 normal cells. At the same time, they were capable of efficiently inducing siRNA downregulation (35%) without loss of activity 7 days post-synthesis. We conclude that LBL-Se-NCs are promising siRNA carriers with enhanced stability and with a dual mode of action against cancer cells.

An investigation of factors affecting the electrospinning of poly (vinyl alcohol)/kefiran composite nanofibers.

This study aimed to investigate parameters affecting the electrospinning of poly (vinyl alcohol) (PVA)/kefiran composite nanofibers. Accordingly, PVA/kefiran composite nanofibers were produced using the electrospinning of PVA, kefiran blend solutions under various electrospinning parameters (such as applied voltage, nozzle-to-collector distance, and polymer injection rate), and solution parameters (such as the ratio of polymers). PVA and kefiran solutions were prepared in 8% and 6% w/w, respectively. Kefiran was blended with PVA solution in different proportions: 70:30, 60:40, 50:50, 40:60, and 30:70. According to the scanning electron microscope (SEM) images, kefiran mixed with PVA in 40:60 ratios produced the best result in nanofiber production. Then, device parameters such as voltage (12, 15, 18, and 20 kV), distance (120, 150, 170, and 200 mm), and polymer injection rates (1, 1.5, 2, and 2.5 mL/h) were changed. The investigation of SEM images showed that the optimal condition for the fabrication of nanofibers was 18 kV, 200 mm, and 1 mL/h. The nanofibers produced in the optimal condition were uniform without knots or adhesion in a small diameter. It was also found that concentration can be regarded as the most effective parameter affecting the diameter of nanofibers. Moreover, the transmission electron microscopy (TEM) image proved that phase separation did not occur between the two polymers. Graphical abstract: Kefiran biopolymer extracted from fermented milk was used in fabrication of PVA/kefiran composite nanofibers using the electrospinning method.

State-of-the-Art of Nanodiagnostics and Nanotherapeutics against SARS-CoV-2.

The pandemic outbreak of SARS-CoV-2, with millions of infected patients worldwide, has severely challenged all aspects of public health. In this regard, early and rapid detection of infected cases and providing effective therapeutics against the virus are in urgent demand. Along with conventional clinical protocols, nanomaterial-based diagnostics and therapeutics hold a great potential against coronavirus disease 2019 (COVID-19). Indeed, nanoparticles with their outstanding characteristics would render additional advantages to the current approaches for rapid and accurate diagnosis and also developing prophylactic vaccines or antiviral therapeutics. In this review, besides presenting an overview of the coronaviruses and SARS-CoV-2, we discuss the introduced nanomaterial-based detection assays and devices and also antiviral formulations and vaccines for coronaviruses.

Serotonin level as a potent diabetes biomarker based on electrochemical sensing: a new approach in a zebra fish model.

Serotonin (5-HT) levels have been associated with several exclusively metabolic disorders. Herein, a new approach for 5-HT level as a novel biomarker of diabetes mellitus is considered using a simple nanocomposite and HPLC method. Reduced graphene oxide (rGO) comprising gold nanoparticles (AuNPs) was decorated with 18-crown-6 (18.Cr.6) to fabricate a simple nanocomposite (rGO-AuNPs-18.Cr.6). The nanocomposite was positioned on a glassy carbon electrode (GCE) to form an electrochemical sensor for the biomarker 5-HT in the presence of L-tryptophan (L-Trp), dopamine (DA), ascorbic acid (AA), urea, and glucose. The nanocomposite exhibited efficient catalytic activity for 5-HT detection by square-wave voltammetry (SWV). The proposed sensor displayed high selectivity, excellent reproducibility, notable anti-interference ability, and long-term stability even after 2 months. SWV defined a linear range of 5-HT concentration from 0.4 to 10 µg L-1. A diabetic animal model (diabetic zebrafish model) was then applied to investigate 5-HT as a novel biomarker of diabetes. A limit of detection (LOD) of about 0.33 µg L-1 was found for the diabetic group and 0.15 µg L-1 for the control group. The average levels of 5-HT obtained were 9 and 2 µg L-1 for control and diabetic groups, respectively. The recovery, relative standard deviation (RSD), and relative error (RE) were found to be about 97%, less than 2%, and around 3%, respectively. The significant reduction in 5-HT level in the diabetic group compared to the control group proved that the biomarker 5-HT can be applied for the early diagnosis of diabetes mellitus.

Layer by Layer Assembled Chitosan-Coated Gold Nanoparticles for Enhanced siRNA Delivery and Silencing.

Delivery of small interfering RNA (siRNA) provides one of the most powerful strategies for downregulation of therapeutic targets. Despite the widely explored capabilities of this strategy, intracellular delivery is hindered by a lack of carriers that have high stability, low toxicity and high transfection efficiency. Here we propose a layer by layer (LBL) self-assembly method to fabricate chitosan-coated gold nanoparticles (CS-AuNPs) as a more stable and efficient siRNA delivery system. Direct reduction of HAuCl4 in the presence of chitosan led to the formation of positively charged CS-AuNPs, which were subsequently modified with a layer of siRNA cargo molecules and a final chitosan layer to protect the siRNA and to have a net positive charge for good interaction with cells. Cytotoxicity, uptake, and downregulation of enhanced Green Fluorescent Protein (eGFP) in H1299-eGFP lung epithelial cells indicated that LBL-CS-AuNPs provided excellent protection of siRNA against enzymatic degradation, ensured good uptake in cells by endocytosis, facilitated endosomal escape of siRNA, and improved the overall silencing effect in comparison with commercial transfection reagents Lipofectamine and jetPEI®. Therefore, this work shows that LBL assembled CS-AuNPs are promising nanocarriers for enhanced intracellular siRNA delivery and silencing.

Effective antibacterial electrospun cellulose acetate nanofibrous patches containing chitosan/erythromycin nanoparticles.

Herein, we fabricated the antibacterial nanofibrous mats composed of cellulose acetate (CA) nanofibers loaded with erythromycin-chitosan nanoparticles (Ery-CS NPs) intended for infected wound dressing. The Ery-loaded CS NPs were prepared by ionic gelation process and then incorporated into the CA electrospun nanofibers (NFs). Regarding physiochemical properties, the NPs and obtained mats were characterized using dynamic light scattering (DLS), scanning electron microscopy (SEM), attenuated total reflection fourier transform infrared (ATR-FTIR), and contact angle measurement. The antimicrobial activity and cell viability of fibroblast cells were also evaluated. The results indicated that Ery was loaded into CS NPs with high encapsulation efficiency (95%). The CA NFs (17% w/v) incorporated with the Ery-CS NPs (12 wt%) displayed smooth homogenous morphology with 141.7 ± 91.7 nm average diameter. The relevant analyses confirmed that the NPs incorporated into NFs and provided high water holding capacity with high porosity. Finally, Ery-CS NPs/CA mats were able to inhibit the growth of both Gram-positive and Gram-negative bacteria as well as showed no cytotoxic effect on the human dermal fibroblast cells. Overall, our findings concluded that the proposed system could be potentially applied as the proper antibacterial mats for infected wound dressing applications.

Cell attachment effects of collagen nanoparticles on crosslinked electrospun nanofibers.

Since collagen is naturally a main extracellular matrix protein, it has been applied widely in skin's tissue engineering scaffolds to mimics the characteristics of extracellular matrix for proper transplantation of living cells. However, there are challenges that come with application of this natural polymer such as high solubility in aqueous environments which requires further consideration such as chemically cross-linking in order to stabilization. But these treatments also affect its functionality and finally cellular behaviors on scaffold. In this research we evaluated the suitability of collagen nanofibers versus collagen nanoparticles for cell adhesion and viability on glutaraldehyde cross-linked scaffolds. Appling a dual-pump electrospining machine a blend PCL-Gelatin from one side and collagen nanofibers or collagen nanoparticles from the other side were collected on the collector. The fabricated scaffolds were characterized by scanning electron microscopy, contact angle, and mechanical analysis. The cell viability, adhesion and morphology were studied respectively using MTT assay, hoechst staining and scanning electron microscopy. The results indicated significantly improvement of cell viability, adhesion and better spreading on scaffolds with collagen nanoparticles than collagen nanofibers. It seems changes in surface morphology, viscoelastic moduli and swelling ability following cross-linking with glutaraldehyde in scaffold with collagen nanoparticles are still favorable for cellular proliferation. Based on these results, in the case of glutaraldehyde cross-linking, application of collagen nanoparticles rather than collagen nanofibers in tissue regeneration scaffolds will better mimic the extracellular matrix characteristics; and preserve the viability and adhesion of seeded cells.