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Laponite is a clay-based material composed of synthetic disc-shaped crystalline nanoparticles with a large and highly ionic surface area. These characteristics enable the intercalation and dissolution of biomolecules in Laponite-based drug delivery systems. Furthermore, Laponite’s innate physicochemical properties and architecture enable the development of tunable pH-responsive drug delivery systems. Laponite’s coagulation capacity and cation exchangeability, determine its exchange capabilities, drug encapsulation efficiency, and release profile. These parameters have been exploited to design highly controlled and efficacious drug delivery platforms for sustained drug release. In this review, we give an overview of how the properties and specific interactions of various Laponite–polymer composite and drug moieties, have been leveraged to design efficient delivery of a number of therapeutics.

In this paper we present fabrication of hollow and solid chitosan microneedles using a recently proposed low-cost and cleanroom-free fabrication method called Cross-Over Lines (COL) laser engraving. COL engraving is achieved using a commercial CO 2 laser-cutter to create microneedle molds on acrylic sheet. PDMS is then casted on the acrylic sheet microneedle mold to create base PDMS microneedles which are then used to generate other polymeric needles. In this paper, we cast and cure chitosan solution on the base PDMS microneedles which easily detaches from PDMS needles on drying. The resulted microneedles are hollow chitosan microneedles. We also made solid microneedles by silanizing and casting PDMSon-PDMS microneedles. We report promising preliminary results on drug delivery using these hollow and solid chitosan microneedles.

We present a facile, low-cost and cleanroom-free technique for the fabrication of microneedles using molds created by laser ablation. Microneedle mold with high aspect ratios is achieved on acrylic sheet by engraving a specific pattern of crossover lines (COL) using CO2 laser cutter. Ablating COL pattern on the acrylic sheet creates a sharp conical shape in the center of the design. We have shown that a variety of microneedle shapes with different heights and tip angles can be easily achieved by changing the number and the length of the COL. Polydimethylsiloxane (PDMS) microneedles were fabricated by casting the PDMS on the mold. The resulted PDMS microneedles are oxygen plasma treated and then silanized. Another PDMS layer is casted on PDMS microneedles and detached after curing. The silanization prevents those two layers of PDMS from bonding to each other and makes them easily detachable. After detachment of the PDMS mold of microneedles, the mold is used to fabricate degradable polyvinyl alcohol microneedle patch suitable for transdermal drug delivery. The release kinetics of the needles are also shown and discussed in order to prove the applicability of the needles. A low-cost method to make microneedles for non-invasive drug delivery across the skin has been devised by a team in the United States. By forming microchannels in the skin, microneedles allow drugs such as insulin to be administered without a painful injection and with improved efficacy. However, conventional methods for fabricating microneedles are expensive, requiring cleanroom facilities. Sameer Sonkusale and co-workers at Tufts University have developed a method that does not require a cleanroom. They use a laser cutter to fabricate molds for microneedles in an acrylic sheet. The cone-shaped molds are created by passing the laser beam through the same point but by different paths, resulting in the greatest amount of material being removed from the central point. The researchers demonstrate their mold by making degradable microneedle patch from various polymers.

Chronic wounds are a major health concern and they affect the lives of more than 25 million people in the United States. They are susceptible to infection and are the leading cause of nontraumatic limb amputations worldwide. The wound environment is dynamic, but their healing rate can be enhanced by administration of therapies at the right time. This approach requires real-time monitoring of the wound environment with on-demand drug delivery in a closed-loop manner. In this paper, a smart and automated flexible wound dressing with temperature and pH sensors integrated onto flexible bandages that monitor wound status in real-time to address this unmet medical need is presented. Moreover, a stimuli-responsive drug releasing system comprising of a hydrogel loaded with thermo-responsive drug carriers and an electronically controlled flexible heater is also integrated into the wound dressing to release the drugs on-demand. The dressing is equipped with a microcontroller to process the data measured by the sensors and to program the drug release protocol for individualized treatment. This flexible smart wound dressing has the potential to significantly impact the treatment of chronic wounds.

Coriander (Coriandrum sativum L.), is an annual herb in the Apiaceae family which disperses in Mediterranean and Middle Eastern regions. The Coriander essential oil has been used in food products, perfumes, cosmetics and pharmaceutical industries for its flavor and odor. In Iran, fruits of Coriander used in pickle, curry powders, sausages, cakes, pastries, biscuits and buns. The aim of this study was to investigate microwave radiation effects on quality, quantity and antimicrobial activity of essential oil of Coriander fruits. The essential oils were obtained from the Coriander fruits by hydrodistillation (HD) and Microwave-assisted hydrodistillation (MAHD) then, the oils were analyzed by GC and GC-MS. Antimicrobial activities of essential oils were evaluated against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans by microdilution method. The results indicated that the HD and MAHD essential oils (EO) were dominated by monoterpenoids such as linalool, geranyl acetate and γ-terpinene. The major compound in both EO was linalool which its amount in HD and MAHD was 63 % and 66 %, respectively. The total amount of monoterpenes hydrocarbons in HD EO differ significantly with the amount in MAHD EO (12.56 % compare to 1.82 %). HD EO showed greater activity against Staphylococcus aureus and Candida albicans than MAHD EO. Moreover, their activities against Ecoli and P. aeruginosa were the same with Minimum Inhibitory Concentration (MIC) 0.781 and 6.25 μL mL(-1), respectively. By using MAHD method, it was superior in terms of saving energy and extraction time, although the oil yield and total composition decrease by using this method.

Proficient antibiotic drug delivery plays a key role in treating infections. In this article we prepared an electrospun wound dressing which releases Tetracycline in a timed and dose controlled matter for one week. In order to fabricate a wound dressing which can release Tetracycline in a longer duration and at an effective therapeutic level we designed a bilayer electrospun patch made of polyvinyl alcohol (PVA), polycaprolacton (PCL), and coated the whole system with chitosan. The SEM micrograph showed the dependent relationship of the morphology of the nanofibers on the Tetracycline concentration, and the addition of PCL electrospun layer decreased the pore size and water uptake rate. However, it was found that coating PVA/PCL bilayered electrospun sheet with chitosan increased the water uptake rate, which is an important property in biomedical applications. According to the FTIR results, chemical composition of the scaffolds did not change during the fabrication process. Mechanical properties of the samples were assessed, and the results revealed that the chitosan coating improved the tensile strength of the electrospun layers. Furthermore, based on in vitro release tests, it was found that bilayered electrospun sheets coated with chitosan controlled drug release efficiently. In addition, the antibacterial tests performed in vitro showed stronger antibacterial activity on S. aureus cultures for PVA/PCL/Chitosan in comparison to uncoated samples.

Minoxidil and Rosemary essential oil have been used for several years to stimulate hair growth. Therefore, coadministration of both Minoxidil and Rosemary essential oil could enhance hair growth. The chemical/biological characteristics of liposomes, which encapsulate both hydrophobic and hydrophilic drugs, can be utilized to encapsulate the herbal and chemical drug concoction concomitantly. A thin-film hydration method was used to prepare the liposomes. The entrapment efficacy of the liposomes was determined for Minoxidil and Rosemary essential oil using UV spectrophotometry and hydrodistillation; as dictated in the European pharmacopeia. Furthermore, a dynamic light scattering (DLS) analysis was conducted to determine the particle size and zeta potential of the prepared liposome. In addition, the storage stability of the liposome was checked after 60 days. The results showed that coencapsulation of Minoxidil and Rosemary essential oil increased the encapsulation efficacy of Minoxidil while the entrapment efficacy of essential oil was not significantly influenced. In addition, according to the DLS results, the particle size and zeta potential of prepared liposomes didn’t change significantly during 60 days of storage.

Topical administration of drugs in a timely manner according to the physiological need at the wound site can enhance the healing rate of chronic wounds. Herein, an electronic wound dressing that enables active topical drug delivery in response to electrically induced pH change is demonstrated for potential treatment of chronic wounds. In this platform, the pH of the dressing is controlled using an electrical field. This allows precise electrical control over the temporal profile of pH-mediated drug release. This engineered dressing is comprised of microfabricated electrodes serving as anode and cathode, a pH sensitive hydrogel, and controlled electronic circuitry. The anode is coated with a pH sensitive poly(ethylene glycol)-diacrylate/Laponite hydrogel layer containing drug loaded chitosan nanoparticles (ChPs). Applying a DC voltage between the electrodes results in a local change in pH near the electrodes. In basic environments found near the anode, the ChPs release their drug due to the dehydration process, while in acidic environments the release profile is negligible. Turning off the DC voltage results in immediate pH recovery and cessation of drug release. The biocompatibility of the dressing has also been confirmed-the pH shift resulting from application of DC voltage does not affect the wound pH significantly.

SiO2-CaO-P2O5 based bioglass (BG) systems constitute a group of materials that have wide applications in bone implants. Chitosan (Cn) is a biocompatible and osteoconductive natural polymer that can promote wound healing. In this study, bioactivity of chitosan/bioglass (CnB) composites as minimally invasive bone regenerative materials was assessed both in vitro and in vivo. Injectability tests and scanning electron microscopy (SEM) results demonstrated the formation of uniform injectable paste-like composites using BG particles and Cn. Fourier transform infrared spectroscopy (FTIR) and SEM images confirmed hydroxyapatite deposition in vitro after incubation in simulated body fluid (SBF). Higher BG content in the composite correlated with increased human osteoblast proliferation. An in vivo study in a rat spinal fusion model confirmed that increasing the amount of BG improved osteoconductivity. Manual palpation, radiographic images and pathological assessments proved that the composites promote bone formation. Based on these data, the synthesized composites have a potential application in orthopedic and reconstructive surgeries as a minimally invasive bone substitute.

Chronic wounds do not heal in an orderly fashion in part due to the lack of timely release of biological factors essential for healing. Topical administration of various therapeutic factors at different stages is shown to enhance the healing rate of chronic wounds. Developing a wound dressing that can deliver biomolecules with a predetermined spatial and temporal pattern would be beneficial for effective treatment of chronic wounds. Here, an actively controlled wound dressing is fabricated using composite fibers with a core electrical heater covered by a layer of hydrogel containing thermoresponsive drug carriers. The fibers are loaded with different drugs and biological factors and are then assembled using textile processes to create a flexible and wearable wound dressing. These fibers can be individually addressed to enable on-demand release of different drugs with a controlled temporal profile. Here, the effectiveness of the engineered dressing for on-demand release of antibiotics and vascular endothelial growth factor (VEGF) is demonstrated for eliminating bacterial infection and inducing angiogenesis in vitro. The effectiveness of the VEGF release on improving healing rate is also demonstrated in a murine model of diabetic wounds.

Background There has been a worldwide concern for the health risks of cigarette smoking and hydrogen cyanide (HCN) considered as one of the hazardous tobacco compounds which is needed to be determined in order to reduce the dose related to smoke disease risk. In this study, we prepare the experimental procedure to entrap the HCN from mainstream smoke of different brands of Tehran cigarette, through simulating human inhalation and determine its concentration applying polarography. Results The HCN level of the 50 commonly consumed tobacco products (47 cigarettes and 3 cigars) obtained from local store is ranged between 17.56 ± 1.02 and 1553.98 ± 0.56 μg per stick, this acquired amount is more than FDA approval (10 μg per stick), so the harmful effects of smoking is indicative. Conclusions The comparative study of the results shows that the price and the weight of each product do not indicate HCN level. As can be seen, R2 value which is a statistical measure of how close the data are to the fitted regression line is low (R2 ’t effect on the amount of HCN and its destructive effects.