**5. Treatments for faster wound healing**

Techniques like cushions, magnetic fields, pressure-relieving beds, ultrasound, and electric fields are also used along with conventional medications. The healing and prevention of pressure wounds are addressed by the aforementioned methods [22].

#### **Figure 12.**

*Schematic representation of four different stages of pressure ulcer and penetration of wound at different stages [18].*

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

**Figure 13.**

*A photograph of diabetic ulcers caused due to repeated mechanical stress, which creates a weakened, insensate foot, heightened by disrupted perfusion [21].*

#### **5.1 Wound healing using laser therapy**

LASER (light amplification by stimulated emission of radiation) therapy is one of the potential methods. The efficiency of LASER therapy is affected by different parameters. There has been a variety of studies to develop this technique for various medical applications [23]. **Figure 14** shows the wound healing procedure using laser therapy.

**Figure 14.**

Recently, lasers have enhanced the nonsurgical method of the wound healing procedure. A therapy of low-power light is a great approach to treat lesions of wounds using light devices like LASER (light amplification by stimulated emission of adiation). A laser is used to repair the biological injury. However, it is not entirely understood the role of laser in reducing pain and repairing tissue. The parameters like optical properties of the tissue, wavelength, and dosage of light affect the interaction of biological tissues and light. Laser has features like various active media types, including solid, liquid, and gaseous materials and also resonant optical cavity [24]. A wide range of therapeutic effects is produced with an account of different irradiation conditions, such as frequency, duration of treatment, and exposure time, and also other laser parameters, such as energy, pulse frequency, pulse duration, power, and wavelength. The wounded cells are affected with suboptimal growth with laser therapy without affecting normal cells [10].

When the dosage of laser therapy was more than 5 J/cm<sup>2</sup> , it revealed more considerable biological effects. It is also shown that at lower doses, no biological effects were *Minimally Invasive Microneedle: A Novel Approach for Drug Delivery System and Infected… DOI: http://dx.doi.org/10.5772/intechopen.105771*

observed, and at very high doses, the cell function is inhibited. Hence an optimum dosage of laser gives better results in wound healing [18].

#### **5.2 Ultrasound therapy for wound healing**

Ultrasound (US) waves have always proven promising therapeutic outcomes for various wounds. The main advantages of US in healing the wound are as follows: highly steering, focusable and high penetration into the wound bed. The physiological mechanisms of US in wound healing are based on its antimicrobial effects. There is no definite dose response observed in the clinical trials of this technique, despite evidence of therapeutic efficiency for chronic wounds in particular. To better understand the dose response and mechanism of action of US methods, more clinical trials and *in vitro* trials are required. **Figure 15** shows the device used for ultrasound therapy [25].

The low US frequencies in the range of 20–120 kHz are used in wound healing applications. The process of producing heat in the tissue by delivering nonionizing radiation in the form of mechanical sound waves is called the therapeutic US, which is a physical method. When the frequencies 1.0 MHz and 3.0 MHz are used to exert the therapeutic US, it attains a depth of 5 cm and even more beneath the body surface. It is also the often used deep-heating modality.

**Figure 15.** *A photograph of a device used for ultrasound therapy [25].*

Very high frequencies of US may cause cell death, whereas low frequencies of US have beneficial effects on the wound [26]. The wound healing procedures, such as gene treatment, fracture repair, sonoporation, sonophoresis, and physiotherapy, use low power of US. By altering the wave intensity and wavelength, the US dosage could be changed. US therapy can either be pulsed or continuous. More heating effects are exerted by continuous US therapy. The pulsed US has on and off cycles; this variation changes the dosage of US therapy [27].
