Magnetically Active Bicontinuous Polymer Structures for Multiple Controlled Drug Delivery.

The targeted delivery of drugs using wireless navigable magnetic robots allows the delivery of drug molecules to be controlled non only in time but also in space, improving medical outcomes. The main disadvantages behind their use lies in the low amount of drug that can be transported and the single nature of drug that can be loaded (hydrophilic or hydrophobic). These considerations limit their use in co-delivery systems, now recognized to be very promising for many different pathologies. A magnetic bijel-like structure is developed to load and release different types of molecules (hydrophilic and hydrophobic). In this work, the use of ε-caprolactone is explored, which can polymerize, forming hydrophobic domains (oil phase). After mixing with iron oxide nanoparticles (NPs), the water dispersion creates a magnetic biphasic porous structure without phase separation. The resulting device shows good performance both in magnetic actuation and as a drug delivery system.

On the role of polymeric hydrogels in the thermal response of gold nanorods under NIR laser irradiation.

Hydrogels are 3D cross-linked networks of polymeric chains designed to be used in the human body. Nowadays they find widespread applications in the biomedical field and are particularly attractive as drug delivery vectors. However, despite many good results, their release performance is sometimes very quick and uncontrolled, being forced by the high in vivo clearance of body fluids. In this direction, the development of novel responsive nanomaterials promises to overcome the drawbacks of common hydrogels, inducing responsive properties in three-dimensional polymeric devices. In this study, we synthesized and then loaded gold nanorods (Au NRs) within an agarose-carbomer (AC)-based hydrogel obtained from a microwave-assisted polycondensation reaction between carbomer 974P and agarose. The photothermal effect of the composite device was quantified in terms of maximum temperature and spatial-temporal temperature distribution, also during consecutive laser irradiations. This work shows that composite Au NRs loaded within AC hydrogels can serve as a stable photothermal treatment agent with enhanced photothermal efficiency and good thermal stability after consecutive laser irradiations. These results confirm that the composite system produced can exhibit an enhanced thermal effect under NIR laser irradiation, which is expected to lead to great therapeutic advantages for the localized treatment of different diseases.

Polymer-based thermoresponsive hydrogels for controlled drug delivery.

INTRODUCTION: Controlled drug delivery through hydrogels is generally limited by the poor barrier that polymeric network can create to diffusion mechanism. Stimuli responsive polymers can help in this way guaranteeing that delivery can be sustained and finely controlled using an external stimulus. AREA COVERED: This review provides an overview of recent studies about the use of temperature as an external stimulus able to work as an efficient new route of drug's administration. Thermoresponsive hydrogels are discussed and compared in terms of physical properties and mechanism of drug release considering their classification in intrinsical (formed by thermosensitive polymers) and non-intrinsical (polymers with thermosensitive moieties) hydrogels. EXPERT OPINION: Thermoresponsive hydrogels can be developed by using different polymers added or not with micro/nanoparticles of organic or inorganic origin. In both cases, the final system represents an innovative way for the local and sustained drug delivery in a specific site of the body. In particular, it is possible to obtain an on-demand release of drug by applying a local increase of temperature to the system.