**6. Wound healing treatment using microneedle**

A different level of success has been achieved using various technologies to treat chronic wounds. Additional treatments like the application of fillers such as collagen sponges, usage of negative wound pressure, hyperbaric oxygen therapy, application of select growth factors, advanced wound dressings, systemic or local antibiotic therapy, and, more recently, the use of cell-based tissue-engineered products have been applied depending on the type and severity of the wound that is being treated [28]. In this section, we have mainly focused on the details of the microneedle, followed by the wound treatment using microneedles.

This technique is based on the use of tiny needles, so small that they are measured in micrometers (millionths of a meter/μm). These microneedles are designed to deliver medicines. In terms of how they work, microneedles are similar to that transdermal patch, for example, the ones used for nicotine delivery that helps people give up smoking compared to the traditional hypodermic needles [17].

The epidermis plays an essential role in acting like a protective layer and keeping things out and protecting all the penetrants. It forms the 10–50 μm layer. When we talk about drug delivery, we mainly aim to get the medicine across this layer. It is this issue from where the concept of the microneedle was developed [29].

Microneedles were made worldwide using the materials like silicon, glass, and metal by the researchers during late 1990s. Microneedles are capable of creating an easier passage to reach the bloodstream in the lower dermal layers. This is a pain-free and easy way of delivering a wide range of medicines across the skin. **Figure 16** is an image of an array of microneedles. **Figure 17** shows the penetration of a conventional needle and a microneedle [30]. The dimensions of the microneedle are as shown in **Figure 18**.

**Figure 16.** *A photograph of a microneedle array [30].*

*Minimally Invasive Microneedle: A Novel Approach for Drug Delivery System and Infected… DOI: http://dx.doi.org/10.5772/intechopen.105771*

#### **Figure 17.**

*Diagrammatic representation of three DDS delivering drugs through various layers of skin: Topical DDS, microneedles-based DDS, and hypodermic needle [31].*
