Polymeric Microneedle Arrays: Versatile Tools for an Innovative Approach to Drug Administration

Nanomaterials-incorporated polymeric microneedles for wound healing applications

There is a growing and urgent need for developing novel biomaterials and therapeutic approaches for efficient wound healing. Microneedles (MNs), which can penetrate necrotic tissues and biofilm barriers at the wound and deliver active ingredients to the deeper layers in a minimally invasive and painless manner, have stimulated the interests of many researchers in the wound-healing filed. Among various materials, polymeric MNs have received widespread attention due to their abundant material sources, simple and inexpensive manufacturing methods, excellent biocompatibility and adjustable mechanical strength. Meanwhile, due to the unique properties of nanomaterials, the incorporation of nanomaterials can further extend the application range of polymeric MNs to facilitate on-demand drug release and activate specific therapeutic effects in combination with other therapies. In this review, we firstly introduce the current status and challenges of wound healing, and then outline the advantages and classification of MNs. Next, we focus on the manufacturing methods of polymeric MNs and the different raw materials used for their production. Furthermore, we give a summary of polymeric MNs incorporated with several common nanomaterials for chronic wounds healing. Finally, we discuss the several challenges and future prospects of transdermal drug delivery systems using nanomaterials-based polymeric MNs in wound treatment application.

Wearable Clinic: From Microneedle-Based Sensors to Next-Generation Healthcare Platforms

The rapid development of wearable biosensing calls for next-generation devices that allow continuous, real-time, and painless monitoring of health status along with responsive medical treatment. Microneedles have exhibited great potential for the direct access of dermal interstitial fluid (ISF) in a minimally invasive manner. Recent studies of microneedle-based devices have evolved from conventional off-line detection to multiplexed, wireless, and integrated sensing. In this review, the classification and fabrication techniques of microneedles are first introduced, and then the representative examples of microneedles for transdermal monitoring with different sensing modalities are summarized. State-of-the-art advances in therapeutic and closed-loop systems are presented to formulate guidelines for the development of next-generation microneedle-based healthcare platforms. The potential challenges and prospects are discussed to pave a new avenue toward pragmatic applications in the real world.

Application of Convergent Science and Technology toward Ocular Disease Treatment

Eyes are one of the main critical organs of the body that provide our brain with the most information about the surrounding environment. Disturbance in the activity of this informational organ, resulting from different ocular diseases, could affect the quality of life, so finding appropriate methods for treating ocular disease has attracted lots of attention. This is especially due to the ineffectiveness of the conventional therapeutic method to deliver drugs into the interior parts of the eye, and the also presence of barriers such as tear film, blood-ocular, and blood-retina barriers. Recently, some novel techniques, such as different types of contact lenses, micro and nanoneedles and in situ gels, have been introduced which can overcome the previously mentioned barriers. These novel techniques could enhance the bioavailability of therapeutic components inside the eyes, deliver them to the posterior side of the eyes, release them in a controlled manner, and reduce the side effects of previous methods (such as eye drops). Accordingly, this review paper aims to summarize some of the evidence on the effectiveness of these new techniques for treating ocular disease, their preclinical and clinical progression, current limitations, and future perspectives.

Biomaterials for Regenerative Medicine in Italy: Brief State of the Art of the Principal Research Centers

Regenerative medicine is the branch of medicine that effectively uses stem cell therapy and tissue engineering strategies to guide the healing or replacement of damaged tissues or organs. A crucial element is undoubtedly the biomaterial that guides biological events to restore tissue continuity. The polymers, natural or synthetic, find wide application thanks to their great adaptability. In fact, they can be used as principal components, coatings or vehicles to functionalize several biomaterials. There are many leading centers for the research and development of biomaterials in Italy. The aim of this review is to provide an overview of the current state of the art on polymer research for regenerative medicine purposes. The last five years of scientific production of the main Italian research centers has been screened to analyze the current advancement in tissue engineering in order to highlight inputs for the development of novel biomaterials and strategies.

A boronate gel-based synthetic platform for closed-loop insulin delivery systems

Diabetes is one of the most devastating global diseases with an ever-increasing number of patients. Achieving persistent glycemic control in a painless and convenient way is an unmet goal for diabetes management. Insulin therapy is commonly utilized for diabetes treatment and usually relies on patient self-injection. This not only impairs a patient’s quality of life and fails to precisely control the blood glucose level but also brings the risk of life-threatening hypoglycemia. “closed-loop” insulin delivery systems could avoid these issues by providing on-demand insulin delivery. However, safety concerns limit the application of currently developed electronics-derived or enzyme-based systems. Phenylboronic acid (PBA), with the ability to reversibly bind glucose and a chemically tailored binding specificity, has attracted substantial attention in recent years. This focus review provides an overview of PBA-based versatile insulin delivery platforms developed in our group, including new PBA derivatives, glucose-responsive gels, and gel-combined medical devices, with a unique “skin layer” controlled diffusion feature.

Recent Advances in the Fabrication and Functionalization of Flexible Optical Biosensors: Toward Smart Life-Sciences Applications

Over the last 30 years, optical biosensors based on nanostructured materials have obtained increasing interest since they allow the screening of a wide variety of biomolecules with high specificity, low limits of detection, and great sensitivity. Among them, flexible optical platforms have the advantage of adapting to non-planar surfaces, suitable for in vivo and real-time monitoring of diseases and assessment of food safety. In this review, we summarize the newest and most advanced platforms coupling optically active materials (noble metal nanoparticles) and flexible substrates giving rise to hybrid nanomaterials and/or nanocomposites, whose performances are comparable to the ones obtained with hard substrates (e.g., glass and semiconductors). We focus on localized surface plasmon resonance (LSPR)-based and surface-enhanced Raman spectroscopy (SERS)-based biosensors. We show that large-scale, cost-effective plasmonic platforms can be realized with the currently available techniques and we emphasize the open issues associated with this topic.

One-Shot Fabrication of Polymeric Hollow Microneedles by Standard Photolithography

Microneedles (MNs) are an emerging technology in pharmaceutics and biomedicine, and are ready to be commercialized in the world market. However, solid microneedles only allow small doses and time-limited administration rates. Moreover, some well-known and already approved drugs need to be re-formulated when supplied by MNs. Instead, hollow microneedles (HMNs) allow for rapid, painless self-administrable microinjection of drugs in their standard formulation. Furthermore, body fluids can be easily extracted for analysis by a reverse use of HMNs, thus making them perfect for sensing issues and theranostics applications. The fabrication of HMNs usually requires several many-step processes, increasing the costs and consequently decreasing the commercial interest. Photolithography is a well-known fabrication technique in microelectronics and microfluidics that fabricates MNs. In this paper, authors show a proof of concept of a patented, easy and one-shot fabrication of two kinds of HMNs: (1) Symmetric HMNs with a “volcano” shape, made by using a photolithographic mask with an array of transparent symmetric rings; and (2) asymmetric HMNs with an oblique aperture, like standard hypodermic steel needles, made by using an array of transparent asymmetric rings, defined by two circles, which centers are slightly mismatched. Simulation of light propagation, fabrication process, and preliminary results on ink microinjection are presented.

Current trends in polymer microneedle for transdermal drug delivery

Transdermal drug delivery using microneedles is increasingly gaining interest due to the issues associated with oral drug delivery routes. Gastrointestinal route exposes the drug to acid and enzymes present in the stomach, leading to denaturation of the compound and resulting in poor bioavailability. Microneedle transdermal drug delivery addresses the problems linked to oral delivery and to relieves the discomfort of patients associated with injections to increase patient compliance. Microneedles can be broadly classified into five types: solid microneedles, coated microneedles, dissolving microneedles, hollow microneedles, and hydrogel-forming microneedles. The materials used for the preparation of microneedles dictate the different applications and features present in the microneedle. Polymeric microneedle arrays present an improved method for transdermal administration of drugs as they penetrate the skin stratum corneum barrier with minimal invasiveness. The review summarizes the importance of polymeric microneedle and discussed some of the most important therapeutic drugs in research, mainly protein drugs, vaccines and small molecule drugs in regenerative medicine.

Non-invasive drug delivery technology: development and current status of transdermal drug delivery devices, techniques and biomedical applications

Pay-load deliveries across the skin barrier to the systemic circulation have been one of the most challenging delivery options. Necessitated requirements of the skin and facilitated skin layer cross-over delivery attempts have resulted in development of different non-invasive, non-oral methods, devices and systems which have been standardized, concurrently used and are in continuous upgrade and improvements. Iontophoresis, electroporation, sonophoresis, magnetophoresis, dermal patches, nanocarriers, needled and needle-less shots, and injectors are among some of the methods of transdermal delivery. The current review covers the current state of the art, merits and shortcomings of the systems, devices and transdermal delivery patches, including drugs' and other payloads' passage facilitation techniques, permeation and absorption feasibility studies, as well as physicochemical properties affecting the delivery through different transdermal modes along with examples of drugs, vaccines, genes and other payloads.