Antimicrobial Activity and Biocompatibility of Antibiotic-Loaded Chitosan Hydrogels as a Potential Scaffold in Regenerative Endodontic Treatment.

INTRODUCTION: The objective of this study was to determine the effectiveness of several antibiotic-loaded hydrogel scaffolds against Enterococcus faecalis, as well as their ability to stimulate proliferation and mineralization of dental pulp stem cells. METHODS: Fibrin (Fg) or chitosan-fibrin hydrogels (Ch) were prepared using 12.5 mg/mL fibrinogen and 0.4% (w/v) chitosan. Triple antibiotics, clindamycin-modified triple antibiotic paste, or double antibiotics were loaded in gels (1 mg/mL). Antibacterial effect against E. faecalis biofilm was determined by using colony-forming units (CFUs) and confocal laser scanning microscope (CLSM). Cell viability and morphology were determined by loading cells into different gels at 7 and 14 days using the water-soluble tetrazolium salt-1 cell viability assay and Live & Dead cell analysis. Mineralization was detected by using alkaline phosphatase and alizarin red staining activity. RESULTS: Antibiotic-loaded Fg gel and Ch gel alone without antibiotics resulted in a significant reduction in CFUs compared with the positive control (P < .05). When antibiotics were loaded in Ch gel, there were no CFUs detected in any groups (P < .05). CLSM images showed dense red areas with mostly dead bacteria on the dentin surface in antibiotic-loaded Ch groups, which showed significantly less live bacteria compared with the other groups (P < .05). Triple antibiotic-loaded Fg and Ch gels resulted in a dramatic decrease in the mineralized nodule formation compared with all other gel groups (P < .05). Ch hydrogels resulted in round cell morphology up to 7 days. Ch alone or with double antibiotic paste showed more cell spreading with spindle-shaped morphology at 14 days and higher alkaline phosphatase activity compared with other antibiotic-loaded Ch groups (P > .05). CONCLUSIONS: Double antibiotic-loaded Ch gel appears to enhance the antibacterial properties while maintaining higher cell viability, cell spreading, and mineralization activity, compared with all the other scaffolds investigated.

Development of besifloxacin HCl loaded nanofibrous ocular inserts for the treatment of bacterial keratitis: In vitro, ex vivo and in vivo evaluation.

Novel drug delivery systems have emerged to treat bacterial keratitis, an acute infection of the cornea. In this study, besifloxacin HCl loaded insert formulations were designed and investigated in vitro, ex vivo and in vivo for the treatment of bacterial keratitis. Besifloxacin HCl (BH) or BH-hydroxypropyl-beta-cyclodextrin (HP-ß-CD) complex containing poly(caprolactone)/polyethylene glycol (PLC/PEG) fibrous inserts were prepared with an electrospinning method. These fibrous inserts were coated with mucoadhesive polymers such as sodium alginate (SA) or thiolated sodium alginate (TSA). Developed inserts compared to commercially available drug and it was found that coating of the insert surfaces with SA and TSA, increases bioadhesion of the formulations. Insert formulations showed a burst release in the first 2 days followed by a slow-release profile. Ex vivo transport studies showed that HP-ß-CD possessed a drug delivery level close to the commercial drug. Both TSA coated inserts as well as inserts containing HP-ß-CD-drug complex were effectively reducing bacterial keratitis in rabbit eyes upon single-dose application compared to multiple dosing with the commercial drug. Consequently, TSA coated inserts as well as the inserts containing HP-ß-CD-drug complex, may be potential alternatives to conventional market product by reducing the application frequency in the clinic leading to increased patient compliance.

A Circulating Bioreactor Reprograms Cancer Cells Toward a More Mesenchymal Niche.

Cancer is a complex and heterogeneous disease, and cancer cells dynamically interact with the mechanical microenvironment such as hydrostatic pressure, fluid shear, and interstitial flow. These factors play an essential role in cell fate and circulating tumor cell heterogeneity, and can influence the cellular phenotype. In this study, a peristaltic continuous flow reactor is designed and applied to HCT-116 colorectal carcinoma cells to mimic the fluid dynamics of circulation. With this intervention, a CD44/CD24-cell subpopulation emerges, and 100 genes are significantly regulated. The expression of cells at 4 h in the flow reactor is very similar to TGF-ß treatment, which is an inducer of epithelial-mesenchymal transition. ATF3 and SERPINE1 are significantly upregulated in these groups, suggesting that the mesenchymal transition is induced through this signaling pathway. This flow reactor model is satisfactory on its own to reprogram colorectal cancer cells toward a more mesenchymal niche mimicking circulation of the blood.

Liposome-based combination therapy for acne treatment.

Acne vulgaris is one of the most common chronic diseases worldwide with the high prevalence ratio of about 80-85% in patients who are in puberty period. For the treatment options, many conventional dosage forms are available; however, existing limitations of systemic administration of drugs (oral antibiotics), such as adverse events and resistance, led for seek of new formulation options. In this study, liposomes containing tetracycline HCl and tretinoin were prepared by the film formation method. In vitro characterization studies revealed that liposomes (111.10 ± 8.02 nm; P.D.I.=0.198 ± 0.03; Z.P.=25.83 ± 0.40 mV) with an encapsulation efficiency more than 80% for both APIs were formulated. In order to maintain a suitable viscosity for topical application, optimized liposomal formulations were dispersed in carbopol-based gel. In vitro release of APIs was sustained for 24 hours with released amounts of 56.44% and 58.44% for tetracycline HCl and tretinoin, respectively. Stability evaluation of both liposomes and liposomes in hydrogels was investigated for 6 months at 4 °C and 25 °C; and no statistically significant change was observed in terms of particle size, zeta potential, encapsulation efficiency, appearance, pH, and viscosity. Cytotoxicity tests confirmed the nontoxic structure of liposomal gel formulations on mice fibroblast cells. In addition, antibacterial efficacy has been proven with Staphylococcus aureus and Streptococcus epidermidis strains as well as the effect on biofilm formation and eradication. As a result, we hereby presented a new combination drug product, which consists of dual active ingredients having comedolytic and bacteriostatic effects in a single, safe, and stable liposome formulation.

A Novel On-Chip Method for Differential Extraction of Sperm in Forensic Cases.

One out of every six American women has been the victim of a sexual assault in their lifetime. However, the DNA casework backlog continues to increase outpacing the nation's capacity since DNA evidence processing in sexual assault casework remains a bottleneck due to laborious and time-consuming differential extraction of victim's and perpetrator's cells. Additionally, a significant amount (60-90%) of male DNA evidence may be lost with existing procedures. Here, a microfluidic method is developed that selectively captures sperm using a unique oligosaccharide sequence (Sialyl-LewisX), a major carbohydrate ligand for sperm-egg binding. This method is validated with forensic mock samples dating back to 2003, resulting in 70-92% sperm capture efficiency and a 60-92% reduction in epithelial fraction. Captured sperm are then lysed on-chip and sperm DNA is isolated. This method reduces assay-time from 8 h to 80 min, providing an inexpensive alternative to current differential extraction techniques, accelerating identification of suspects and advancing public safety.

Gold nano-decorated aligned polyurethane nanofibers for enhancement of neurite outgrowth and elongation.

Neurite outgrowth and elongation of neural cells is the most important subject that is considered in nerve tissue engineering. In this regard, aligned nanofibers have taken much attention in terms of providing guidance for newly outgrown neurites. The main objective of this study was to fabricate aligned polyurethane nanofibers by electrospinning process and decorate them with gold nanoparticles to further investigate the synergistic effects of nanotopography, biological nerve growth factor (NGF) and electrical stimulations on neurite outgrowth and elongation of pheochromocytoma (PC-12) model cells. In this regard, smooth and uniform aligned polyurethane nanofibers with the average diameter of 519 ± 56 nm were fabricated and decorated with the gold nanoparticles with the average diameter of ∼50 nm. PC-12 cells were cultured on the various nanofiber surfaces inside the bio-mimetic bioreactor system and exposed either to NGF alone or combination of NGF and electrical stimulation. It was found that 50 ng/mL NGF concentration is an optimal value for the stimulation of neurite outgrowth. After 4 days of culture under 100 mV, 10 ms electrical stimulation in 1 h/day period it was found that the gold nanoparticle decorated aligned polyurethane nanofibers increased the neurite outgrowth and elongation more with the combinational NGF and electrical stimulation. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1604-1613, 2018.

An overview of nanofiber-based antibacterial drug design.

INTRODUCTION: Conventional administration of antibacterial drugs to the human body can cause vital problems such as dose dependent systemic toxicity and bacterial resistance which prevent the healing process. In this regard, recent studies have been devoted to producing nanofiber based antibacterial drug delivery approaches which surpass bacterial resistance and toxicological issues. Areas covered: This review summarizes latest developments in the production of antibacterial nanofibers, nanofiber based antibacterial action mechanisms and release profiles of nanofibers. In the first section, key challenges of antibacterial nanofibers and release and non-release antibacterial action mechanisms of nanofibers are highlighted. In the second section, routes of antibacterial nanofiber design have been given. Factors affecting drug release mechanisms have been discussed elaborately in the final section. Literature was surveyed from research articles, standard sources (WOS and Scopus) and clinical trials. Expert opinion: New generation nanofibers provide high drug loading capacity and efficiency with their high surface area and tunable pore size. They also enable sustained and controlled release of antibacterial drugs with basic (direct incorporation, physically adsorption or chemically surface modification of antibacterial drugs), advanced (core-shell structure, nanoparticle decorated and multidrug loaded) and smart (stimuli responsive) antibacterial nanofiber design strategies.

In vivo tissue distribution and efficacy studies for cyclosporin A loaded nano-decorated subconjunctival implants.

Biodegradable implants are promising drug delivery systems for sustained release ocular drug delivery with the benefits such as minimum systemic side effects, constant drug concentration at the target site and getting cleared without surgical removal. Dry eye syndrome (DES) is a common disease characterized with the changes in ocular epithelia surface and results in inflammatory reaction that might lead to blindness. Cyclosporin A (CsA) is a cyclic peptide that is frequently employed for the treatment of DES and it needs to be applied several times a day in tear drops form. The aim of this study was to evaluate in vivo behavior and efficacy of the developed nano-decorated subconjunctival implant systems for sustained release CsA delivery. Biodegradable Poly-ɛ-caprolactone (PCL) implant or micro-fiber implants containing CsA loaded poly-lactide-co-glycolide (85:15) (PLGA) or PCL nanoparticles were prepared in order to achieve sustained release. Two of the formulations PCL-PLGA-NP-F and PCL-PCL-NP-I were selected for in vivo evaluation based on their in vitro characteristics determined in our previous study. In this study, formulations were implanted to Swiss Albino mice with induced dry eye syndrome to investigate the ocular distribution of CsA following subconjunctival implantation and to evaluate the efficacy. Tissue distribution study indicated that CsA was present in ocular tissues such as cornea, sclera and lens even 90 days after the application and blood CsA levels were found lower than ocular tissues. Efficacy studies also showed that application of CsA-loaded fiber implant formulation resulted in faster recovery based on their staining scores.

Integrating Cell Phone Imaging with Magnetic Levitation (i-LEV) for Label-Free Blood Analysis at the Point-of-Living.

There is an emerging need for portable, robust, inexpensive, and easy-to-use disease diagnosis and prognosis monitoring platforms to share health information at the point-of-living, including clinical and home settings. Recent advances in digital health technologies have improved early diagnosis, drug treatment, and personalized medicine. Smartphones with high-resolution cameras and high data processing power enable intriguing biomedical applications when integrated with diagnostic devices. Further, these devices have immense potential to contribute to public health in resource-limited settings where there is a particular need for portable, rapid, label-free, easy-to-use, and affordable biomedical devices to diagnose and continuously monitor patients for precision medicine, especially those suffering from rare diseases, such as sickle cell anemia, thalassemia, and chronic fatigue syndrome. Here, a magnetic levitation-based diagnosis system is presented in which different cell types (i.e., white and red blood cells) are levitated in a magnetic gradient and separated due to their unique densities. Moreover, an easy-to-use, smartphone incorporated levitation system for cell analysis is introduced. Using our portable imaging magnetic levitation (i-LEV) system, it is shown that white and red blood cells can be identified and cell numbers can be quantified without using any labels. In addition, cells levitated in i-LEV can be distinguished at single-cell resolution, potentially enabling diagnosis and monitoring, as well as clinical and research applications.

Multitarget, quantitative nanoplasmonic electrical field-enhanced resonating device (NE2RD) for diagnostics.

Recent advances in biosensing technologies present great potential for medical diagnostics, thus improving clinical decisions. However, creating a label-free general sensing platform capable of detecting multiple biotargets in various clinical specimens over a wide dynamic range, without lengthy sample-processing steps, remains a considerable challenge. In practice, these barriers prevent broad applications in clinics and at patients' homes. Here, we demonstrate the nanoplasmonic electrical field-enhanced resonating device (NE(2)RD), which addresses all these impediments on a single platform. The NE(2)RD employs an immunodetection assay to capture biotargets, and precisely measures spectral color changes by their wavelength and extinction intensity shifts in nanoparticles without prior sample labeling or preprocessing. We present through multiple examples, a label-free, quantitative, portable, multitarget platform by rapidly detecting various protein biomarkers, drugs, protein allergens, bacteria, eukaryotic cells, and distinct viruses. The linear dynamic range of NE(2)RD is five orders of magnitude broader than ELISA, with a sensitivity down to 400 fg/mL This range and sensitivity are achieved by self-assembling gold nanoparticles to generate hot spots on a 3D-oriented substrate for ultrasensitive measurements. We demonstrate that this precise platform handles multiple clinical samples such as whole blood, serum, and saliva without sample preprocessing under diverse conditions of temperature, pH, and ionic strength. The NE(2)RD's broad dynamic range, detection limit, and portability integrated with a disposable fluidic chip have broad applications, potentially enabling the transition toward precision medicine at the point-of-care or primary care settings and at patients' homes.

Nanofibers based antibacterial drug design, delivery and applications.

Infections caused by microorganisms like bacteria, fungi, etc. are the main obstacle in healing processes. Conventional antibacterial administration routes can be listed as oral, intravenous/intramuscular, topical and inhalation. These kinds of drug administrations are faced with critical vital issues such as; more rapid delivery of the drug than intended which can result in bacterial resistance, dose related systemic toxicity, tissue irritation and finally delayed healing process that need to be tackled. Recently, studies have been focused on new drug delivery systems, overcoming resistance and toxicological problems and finally localizing the molecules at the site of action in a proper dose. In this regard, many nanotechnological approaches such as nanoparticulate therapeutic systems have been developed to address accompanying problems mentioned above. Among them, drug loaded electrospun nanofibers propose main advantages like controlled drug delivery, high drug loading capacity, high encapsulation efficiency, simultaneous delivery of multiple drugs, ease of production and cost effectiveness for pharmaceutical and biomedical applications. Therefore, some particular attention has been devoted to the design of electrospun nanofibers as promising antibacterial drug carrier systems. A variety of antibacterials e.g., biocides, antibiotics, quaternary ammonium salts, triclosan, metallic nanoparticles (silver, titanium dioxide, and zinc oxide) and antibacterial polymers (chitosan, polyethyleneimine, etc.) have been impregnated by various techniques into nanofibers that exhibit strong antibacterial activity in standard assays. This review highlights the design and delivery of antibacterial drug loaded nanofibers with particular focus on their function in the fields of drug delivery, wound healing, tissue engineering, cosmetics and other biomedical applications.

Preparation and in vitro/in vivo evaluation of cyclosporin A-loaded nanodecorated ocular implants for subconjunctival application.

In terms of ocular drug delivery, biodegradable implant systems have several advantages including the ability to provide constant drug concentration at the target site, no necessity for surgical removal, and minimum systemic side effects. Cyclosporin A (CsA) is a neutral, hydrophobic, cyclic peptide of amino acids that frequently used for dry eye disease treatment. The aim of this study was to develop a nanoparticle-loaded implant system for sustained-release CsA delivery following subconjunctival implantation. Poly(lactide-co-glycolide) (85:15) or poly-ε-caprolactone (PCL) were used to prepare two different nanoparticle formulations. These nanoparticles loaded into PCL or poly(lactide-co-caprolactone) implant formulations were prepared by two different methods, which were molding and electrospinning. Size and zeta potential of nanoparticles were determined and the morphology of the formulations were investigated by scanning electron microscopy. CsA-loading efficiencies were calculated and the in vitro degradation and in vitro release studies were performed. MTT test was also performed using L929 fibroblast cells to evaluate the cytotoxicity of the formulations. PCL-PCL-NP-I formulation was implanted to Swiss Albino mice with induced dry eye syndrome to evaluate the efficacy. In vitro release studies showed that the release from the formulations continues between 30 and 60 days, and the cell viability was found to be 77.4%-99.0%. In vivo studies showed that healing is significantly faster in the presence of the selected implant formulation. Results indicated that nanodecorated implants are promising ocular carriers for controlled-release CsA application.

Silk fibroin based antibacterial bionanotextiles as wound dressing materials.

New applications for medical biotextiles have been identified with the development of nanotechnological manufacturing technologies. Combination of nanotechnology and biotextile technology has resulted into a new field called bionanotextiles. Bionanotextiles are used in many areas which include wound dressings, bandages and tissue scaffolds. Silk fibroin (SF) from the cocoon of Bombyx mori, is one of the most favorable wound dressing materials due to its unique properties including biocompatibility, permeability, biodegradability, morphologic flexibility, and proper mechanical properties. The modification of antimicrobial properties of SFs can provide a barrier for bacterial penetration as wound dressing materials. In the present study, antibacterial polyethylenimine (PEI) (10, 20 and 30% (w/w)) was blended with SF and bionanotextiles were successfully fabricated by electrospinning. In addition, silk fibroin nanofibers were also functionalized with sulphate group in order to test whether they exhibit an antibacterial activity or not. Fibroin based bionanotextiles were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The cytotoxicity evaluations were carried out by L929 fibroblasts with MTT assay. The indirect cytotoxicity results demonstrate that all fibroin and PEI/fibroin extracts have no cytotoxicity on L929 cancer cell line. PEI/fibroin bionanotextiles showed strong antibacterial activities against gram positive Staphylococcus aureus and gram negative Pseudomonas aeruginosa.