Impact Of UV Light in Sterilising Open Wounds

Introduction

Wound sterilisation is an important aspect in healthcare settings to prevent the spread of infections and their prevention is a top priority. Infected wounds can lead to complications for patients, as well as increasing healthcare-related costs. Therefore, it is paramount that an effective technique to sterilise wounds is available.

Among the more innovative approaches to wound sterilisation, is the use of Ultraviolet (UV) light. In this article, we will delve into the impact of UV light in wound sterilisation, its mechanism of action, as well as the limitations and advantages of this technique.

Understanding UV Light

Ultraviolet (UV) light is a segment of electromagnetic radiation with a wavelength that is longer than X-rays but shorter than violet light.¹ UV light possesses unique properties such as being germicidal and having the ability to inactivate viruses and kill microorganisms.² Its ability to do such actions has made it a great source of interest within healthcare to sterilise open wounds. UV light can be categorised into three main types, including UVA, UVB, and UVC. UVC is the most researched and well-known for being effective at sterilising pathogens in wounds.² By understanding how UV light interacts with microorganisms, we will be able to understand its ability to sterilise wounds.

Mechanism of UV sterilization

UV light has the ability to disrupt the genetic material of pathogens, rendering them harmless. 

For bacteria,  it forms dimers in RNA and DNA, which in turn causes damage within the cell of the bacteria.³ Through this damage, the bacterial cell’s ability to replicate and transcribe is interfered with, thus leading to bacterial cell death.³ 

In terms of viruses, one of the methods explored to eliminate SARS-CoV-2 (Covid-19) was through the use of UVC irradiation. A study conducted by Storm et al (2020)⁴ looked into the ability of UVC to inactivate the virus on contaminated surfaces. It was found that when the virus was exposed to UVC at a wavelength of 254 nm, it received photochemical damage by absorbing the light.

This damage affected its ability to replicate and spread.⁴ Storm et al (2020)⁴ elucidated that UVC can inactivate viruses by conducting continuous experiments in the same study. The results showed that the virus’s infectivity fell below detectable levels whilst being partially inactivated.

UV light sources

One of the ways to increase the efficacy of wound sterilisation is by choosing the correct UV light from the correct source. Sources of UV light vary in their efficacy of dealing with microorganism, their wavelength, and application.

One of the sources of UV light are UV lamps. UV lamps are fairly older technology and therefore have been a staple for decades in the field of sterilisation. UV lamps have the capacity to emit differing wavelengths which produce UVA, UVB, and UVC light, however as discussed UVC is known best for its germicidal properties comparative to UVA and UVB.

Low-pressure mercury vapour lamps (LPML)

A specific source of germicidal UV irradiation.

• They have been used to sterilise surfaces, air, and water for almost a century 
• Currently the most efficient and practical method of producing and using germicidal UV light⁵ 
• LPML’s can relay around 80 percent of the UV light produced by mercury at a wavelength of 253.7 nm⁵  
• Can be used in a wide range of environments
• Krypton-chloride excimer lamps (KCEL)

Another source of UVC 

• KCELsgenerate large emissions of UVC at a lower wavelength of 222 nm⁵
• Pathogens such as bacteria and viruses can be inactivated in more specific areas (such as the air), 
• Their use in wound sterilisation is yet to be acknowledged, but they possess noticeable potential

UV-C LEDs

The most recent development and another source of UV light for wound sterilisation. 

There are several advantages that UV-C LEDs offer comparing to the discussed options above:⁵

• A more compact shape and size for easier manoeuvrability and transportation as needed. Available in handheld devices for wound sterilisation
• The capacity to emit light at a range of specific wavelengths, ensuring that pathogens can be eliminated with maximum efficiency
• Longer lifespan than UV lamps: reduces the cost associated with maintenance and the need for replacements
• Instantaneous: No need to wait time to heat up or cool down, unlike UV lamps
• Flexibility and controllability: they provide more form flexibility, and if a wound needs to be pulsed with light as opposed to continuous exposure, then the radiation generated from UV-C LEDs is very responsive to controlled electrical current waveforms

Factors to be taken into consideration

From the discussion above, in the interest of sterilising wounds, the correct source and technology must be used and therefore in order to find identify the appropriate UV light source several factors must be taken into consideration:

1. Wavelength – depending on the microorganisms and the area of the body affected, different wavelengths may need to be used. i.e. if the wound is deeper and affecting tissue, shorter wavelengths may be required⁶
2. Intensity – UV-C LEDs provide more control of intensity
3. Application – if the wound sterilisation device needs to be handheld or easy to carry and portable then UV-C LEDs are more applicable, however if a larger surface area needed to have been covered then UV lamps may be a more suitable option
4. Cost – the maintenance and operating expenses should also be taken into account as well as whether a light source is a suitable investment over time by factoring how long its lifespan is compared to how effective it is at sterilising wounds
5. Safety – as the light sources will most likely be used to sterilise human wounds, it is important that the UV light sources are safety compliant and have safety features which protects both the user and the one who administers from radiation

Safety considerations

Keeping safe whilst using UV light is incredibly important when sterilising wounds. Some potential risks from prolonged exposure to UV light includes cross-contamination and skin and eye damage.

If the devices of wound sterilisation are not handled correctly or are unkempt, this may lead to health worsening health consequences. 

Diseases such as erythema may arise, therefore, safety considerations must be implemented in protocol before using UV in healthcare and wound sterilisation.⁷

When using UV light in healthcare settings, it is important to consider the guidelines illustrated by the governing bodies in your countries, for example, the FDA in the United States of America or the GMC in the United Kingdom. More local safety protocols to ensure efficiency in wound sterilisation, as well as safety, involves the use of protective gear such as PPE to minimise UV exposure, ensured adequate training of healthcare staffs, and regular maintainence of UV devices to enable the correct dosage delivery to patients.

Applications in wound sterilization

Understanding UV light applications is crucial for effective implementation in healthcare. Portable UV-C LEDs do not always entail efficiency, as they require constant care from healthcare professionals. Thus, in recent years, UV-equipped wound dressings with integrated electronics have been researched, for their benefit of providing up-to-date monitoring of the treatment to the healthcare professionals.⁸

Currently, traditional negative pressure wound therapy (NPWT) is used to optimise wound healing and reduce inflammation whilst promoting tissue healing.⁹ Research conducted by Kathryn et al (2023) used UV light in conjunction with NPWT demonstrated greater wound healing and when exposed to bacteria such as Staphylococcus aureus, the colony number decreased, suggesting a promising new treatment option.¹⁰

When comparing UV light wound sterilisation to more traditional forms of wound sterilisation, there are many clear-cut advantages, the most important being chemical-free. It is eco-friendly as it reduces waste chemical waste, also more cost-effective and reducing dependency on antibiotics by preventing infections from wounds.

Challenges and limitations

Although UV light as a wound sterilisation technique is promising and effective from the studies explored, it does pose some limitations which need to be addressed before being relied heavily in healthcare. Some challenges include:

• Safety concerns 
• The cost of devices with maintenance
• Lack of uniform exposure to UV for more morphologically complex wounds 
• Difficulty in adjusting in appropriate positions for certain individuals due to movement difficulty 
• Other challenges: microbial resistance to UV light, microbial load, and tissue depth requiring longer UV exposure^11,12 

Benefits and advantages

Whilst the risks and challenges of UV light use are notable, UV lights should be valued for their:

• Reduced rate of infections – as UV light inactivates pathogens, the risk of infection within the wound decreases
• Lower treatment costs – with fewer wounds developing into infections, hospital stays are decreased and, as are cost-related burdens on healthcare systems
• Chemical-free sterilisation – UV light reduces the need for harsh chemically based disinfectants being used. Not to mention if patients had any allergies to certain ingredients, there is now an alternative approach available
• Environmentally, UV light reduces chemical waste, may result in long-term cost effectiveness by reducing infection-related costs, as well as being energy efficient particularly with UV-C LEDs
• Enhanced quality of care and healthcare provision: thanks to reduced nosocomial infection incidence, patients can expect reduced risk and faster recovery¹³

Summary

The article explores UV light's potential in wound sterilization, emphasizing its germicidal properties, mechanisms of action, and various sources, including UV-C LEDs. UV light offers benefits such as reduced infections, lower treatment costs, and eco-friendly sterilization. Safety considerations and challenges, such as device costs, are acknowledged. Despite potential limitations, UV light has the capacity to revolutionize wound treatment in healthcare, providing a chemical-free alternative with improved patient care.