The role of microneedles in the healing of chronic wounds.

Chronic wounds occur for several reasons, such as trauma, accidents, and diseases. Diabetes has been one of the primary causes of non-healing wounds, and the number of people with diabetes is increasing in most countries. Wounds in diabetic people have a complex and prolonged treatment process, with high treatment costs to both healthcare providers and patients.

Fabrication and testing of polymer microneedles for transdermal drug delivery.

Microneedle (MN) patches have considerable potential for medical applications such as transdermal drug delivery, point-of-care diagnostics, and vaccination. These miniature microdevices should successfully pierce the skin tissues while having enough stiffness to withstand the forces imposed by penetration. Developing low-cost and simple manufacturing processes for MNs is of considerable interest.

An overview of microneedle applications, materials, and fabrication methods.

Microneedle-based microdevices promise to expand the scope for delivery of vaccines and therapeutic agents through the skin and withdrawing biofluids for point-of-care diagnostics - so-called theranostics. Unskilled and painless applications of microneedle patches for blood collection or drug delivery are two of the advantages of microneedle arrays over hypodermic needles. Developing the necessary microneedle fabrication processes has the potential to dramatically impact the health care delivery system by changing the landscape of fluid sampling and subcutaneous drug delivery.

High-resolution two-photon polymerization: the most versatile technique for the fabrication of microneedle arrays.

Microneedle patches have received much interest in the last two decades as drug/vaccine delivery or fluid sampling systems for diagnostic and monitoring purposes. Microneedles are manufactured using a variety of additive and subtractive micromanufacturing techniques. In the last decade, much attention has been paid to using additive manufacturing techniques in both research and industry, such as 3D printing, fused deposition modeling, inkjet printing, and two-photon polymerization (2PP), with 2PP being the most flexible method for the fabrication of microneedle arrays.

Charged particle single nanometre manufacturing.

Following a brief historical summary of the way in which electron beam lithography developed out of the scanning electron microscope, three state-of-the-art charged-particle beam nanopatterning technologies are considered. All three have been the subject of a recently completed European Union Project entitled "Single Nanometre Manufacturing: Beyond CMOS". Scanning helium ion beam lithography has the advantages of virtually zero proximity effect, nanoscale patterning capability and high sensitivity in combination with a novel fullerene resist based on the sub-nanometre C molecule.

High-fidelity replication of thermoplastic microneedles with open microfluidic channels.

Development of microneedles for unskilled and painless collection of blood or drug delivery addresses the quality of healthcare through early intervention at point-of-care. Microneedles with submicron to millimeter features have been fabricated from materials such as metals, silicon, and polymers by subtractive machining or etching. However, to date, large-scale manufacture of hollow microneedles has been limited by the cost and complexity of microfabrication techniques.

Estimation of AFM tip shape and status in linewidth and profile measurement.

An atomic force microscopy image is a dilation of the specimen surface with the probe tip. Tips wear or are damaged as they are used. And AFM tip shape and position status make AFM images distorted.

Replication of micro-optical elements with continuous relief by ultraviolet embossing with thiol-ene-based resist.

We propose in this paper to use the delayed gel point character of thiol-ene-based resist to reduce the influence of polymerization shrinkage during the replication of micro-optical elements with continuous relief by UV embossing. Experiment results indicate that this resist can be used to bring down the fabrication error to less than 2% in the vertical direction at a proper thickness of the residual resist, which is far less than that of traditional acrylate-based resist. This resist can also be used to transfer continuous relief into a fused silica substrate through reactive ion etching because of its good etching resistance.