AMG antimicrobial glove is the world’s first non-leaching antimicrobial glove, designed to kill microbes on the outer glove surface rapidly upon contact.
Though conventional glove provides a barrier between the healthcare worker and patient, it does not tackle the problem of transient transmission, where microbes get transmitted from one surface to another. AMG antimicrobial glove is designed to help reduce the spread of HAI, as it is proven to kill up to 99.999% of selected microbes.
The use of medical gloves is intended to prevent cross-contamination between the patient, the user and its environment.
However, conventional gloves can only provide passive protection as contaminated gloves caused by improper storage, inappropriate use and techniques for donning and removing may, in turn, become a vehicle for transmission of microbes.
Conversely, gloves with AMG technology provide a novel approach in HAIs prevention as the gloves can continuously and effectively reduce or inhibit microbial colonisation on the glove surface within a short amount of time, thus further reducing the risk of cross-contamination.
Although AMG antimicrobial glove has been found effective against a wide range of microbes, it does not replace the need for hand hygiene. Instead, AMG antimicrobial glove complements hand hygiene practice and serves as an extra precaution or tool to help mitigate the spread of HAIs.
The AMG technology uses a special dye that absorbs visible light, which raises it from a ground state to an excited quantum state, causing an elevation in energy to take place. The energy then transfers to a proximal oxygen molecule found in the air, causing the oxygen molecule to also rise to an excited quantum state. The ground state of oxygen present in the air is a triplet electronic configuration, written as 3O2. Upon sensitisation by the dye molecule, the electronic configuration changes and enters the singlet oxygen state, 1O2.
This singlet oxygen state is highly reactive and more oxidative compared to ground state oxygen and therefore, is able to kill microbes such as bacteria by oxidising the cells’ protein and lipid. Using the dye as a catalyst, singlet oxygen can be generated continuously as it absorbs light and air.
Singlet oxygen is a non-selective system that can react rapidly against many microbial components. There is no single protection mechanism that bacteria can use to protect themselves from singlet oxygen. This is in contrast to antibiotics, which needs a very specific mechanism to kill the bacteria. As singlet oxygen is transient, it does not lead to the release of persistent biocides into the environment.
AMG technology will, as such, transform the standard examination glove from a passive medical device to a medical device that will reduce or inhibit microbial colonisation.
Whilst it has not received as much attention as traditional biocides, singlet oxygen has been researched for a wide range of uses for many years and a number of important commercial applications are known.
In humans, singlet oxygen-generating dyes are used for cancer treatment, known as photodynamic therapy, PDT.
It is also used in dental disinfection prior to procedures like root canal treatment, in which the dye is rinsed into a patient’s mouth, with light then applied causing disinfection to occur safely and rapidly.
However, probably the most ubiquitous use is in laundry powders, where singlet oxygen-generating dye is washed onto clothing, and subsequently acts as a photobleach. Many people will, therefore, be unwitting users of singlet oxygen and will be wearing items containing some singlet oxygen-generating dye.
Experimental studies have been done and reported in scientific literatures about singlet oxygen’s efficacy and microbial resistance. These have shown that bacteria were killed to a great extent with singlet oxygen, typically 99.9% or 99.99%, leaving only the most robust bacteria. These bacteria were then re-cultivated and re-exposed to singlet oxygen. This cycle was repeated 10 or 20 times, with the efficacy of kill measured. In all cases, it was found that there was no decrease in efficacy and no development in resistance.
Many of the mechanisms bacteria used to confer resistance involve processes internal to the cell. In the AMG system, however, the singlet oxygen is generated purely exogenously to the cell – the dye is separated from the bacteria, does not leach, and cannot enter the cell. Other authors have noted that this makes the development of resistance especially difficult because singlet oxygen is short-lived and has a short length of diffusion – nothing the bacterial cell does internally will affect the process of oxidation by singlet oxygen.
Furthermore, a review of the potential for resistance to biocidal materials was done by the EU expert scientific committee. The report classifies biocidal materials into three categories: low risk of inducing resistance, medium risk and high risk. Oxidative systems were categorised as low risk, some traditional biocidal materials such as chlorhexidine and polyhexamethylene biguanide (PHMB) as medium risk, and silver as high risk.
Testing of AMG antimicrobial glove has been conducted under general lighting conditions of 1000 lux and 500 lux, which are common at hospital settings. Results show that there was no significant difference in bactericidal efficacy.
No. The AMG technology is activated by any white light source in the 600-700 nm region, irrespective of lighting type.
No. Singlet oxygen will be generated continuously as long as there are light and air. Heat-aged AMG antimicrobial gloves (accelerated ageing equivalent to 3 years’ shelf life) did not show any significant difference in bactericidal efficacy compared to fresh AMG antimicrobial gloves.
AMG antimicrobial gloves were also subjected to amount of light which is equivalent to 30 days’ exposure in an open box environment. Again, there was no significant difference in bactericidal efficacy compared to fresh AMG antimicrobial gloves.
AMG technology requires light for generation of singlet oxygen to exert its antimicrobial action. Under dimly lit environment, AMG’s efficacy will be adversely affected. When the AMG gloves are soiled, this may also inhibit the effectiveness of singlet oxygen antimicrobial system due to disruption with light absorption. According to WHO’s recommendation, gloves should be removed after tasks involving contact with blood, another body fluid, non-intact skin or mucous membrane, have ended.
We designed the AMG antimicrobial gloves to be non-leaching, so that the catalytic dye, which is a photosensitiser, does not transfer to the patient. To further ensure its safety, the gloves were tested for leaching extractables as per below.
i. Tested at Intertek UK, the gloves were extracted using hot water, artificial saliva, artificial sweat and ethanol. These extracts were then analysed by validated analytical techniques to detect the presence of the photosensitiser. None of the photosensitiser could be detected from the gloves’ inner or outer surface.
ii. ISO 10993 biocompatibility testing has been conducted on the inner and outer surfaces of the gloves. Results confirmed that the gloves are non-sensitising, non-irritating, non-toxic (oral) and non-cytotoxic.
iii. The Modified Draize-95 test was also conducted where both the inner and outer surfaces of the gloves were tested on human skin. The gloves provided no clinical evidence of inducing allergic reactions. With this test result, the U.S. FDA allows a “Low Dermatitis Potential” claim for the gloves.
The AMG technology is only introduced on the outer surface of the glove while the glove user is exposed to the donning side of the glove, which is similar to a standard examination glove. Hence, the skin of the glove user is not exposed to this technology.
Bacteria are classified into Gram-positive or Gram-negative. This classification came from a staining property observed by Hans Gram in 1884. It was observed that some bacteria could be stained with a dye, and others could not. It was later found that bacteria have different cell wall structures. Gram-positive bacteria allow substances to cross the cell wall more easily. The cell wall of Gram-negative bacteria is multi-layered and so it is harder for substances to cross the cell wall.
Gram-positive bacteria include MRSA, Staphylococcus aureus, Enterococcus faecium, Streptococcus pyogenes, Enterococcus faecalis (VRE) among many others.
Gram-negative bacteria include Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii among others.
Based on a study conducted by Hirai, which measures the survival of different types of bacteria on cotton lint, the results showed that Gram-positive bacteria have longer lifetimes on surfaces, which may have implications that these bacteria are more readily available for transfer to cause HAIs. Gram-negative bacteria are known to die more quickly on surfaces, especially if the surface is dry.
The pattern of lower survival of Gram-negative bacteria is also seen in the clinical environment. In Wilson et al. study, Gram-positive bacteria such as S. aureus were found in numerous locations in the hospital environment, but Gram-negative bacteria such as E. Coli were not found on any surfaces sampled, despite having a number of patients in the ward with E. Coli infections.
All bacteria respond to biocides differently, requiring different contact times and concentrations for inactivation. In general, Gram-negative bacteria are harder to be killed with biocides.
AMG antimicrobial glove will start generating singlet oxygen and start killing bacteria immediately upon exposure to light and oxygen. Based on the requirements of ASTM D7907-14, the contact times in which the bacteria are exposed to the outer surface of the glove containing antimicrobial agent needs to be measured at intervals of 5 mins, 10 mins, 20 mins and 30 mins.
At the end of each contact time, the glove is transferred into a validated neutraliser to stop the bactericidal activity. This will stop the singlet oxygen killing activity on the microbes to facilitate the calculation of bacteria killed.
Additional testing has been conducted at shorter contact times of 1 min and 2 mins on Staphylococcus aureus with bacteria kill rates of 99.898% and 99.998% respectively.
Most HAIs attributable to hand-surface contamination are caused by bacteria. Viruses like the hepatitis B virus (HBV) and human immunodeficiency virus (HIV) are spread through the faecal-oral route or transmission through contaminated syringes, needles, sharps, or infected blood transfusions. The more common flu viruses are mainly spread by droplets made when flu patients cough, sneeze or talk. These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs. Less often, a person might get flu by touching a surface or object that has flu virus on it and then touching their mouth, nose, or possibly eyes.
All of our bactericidal tests are conducted based on ASTM D7907 Standard Test Methods for Determination of Bactericidal Efficacy on the Surface of Medical Examination Gloves, which necessitates the testing against four specific bacteria. As AMG technology is a novel invention, there are no other existing standards that we can adopt to test for antiviral efficacy. Nevertheless, we are working on adapting the D7907 standard to test for viruses, and this takes time to complete. One of the challenges encountered is that viruses only replicate inside living cells; once exposed to the environment, they will be destroyed quickly. This further complicates the testing process and at present, no conclusion can be drawn on the antiviral claim.
Under European Union MDD 93/42/EEC Annex IX:
Class I (Rule 5) includes “All invasive devices with respect to body orifices, other than surgically invasive devices and which are not intended for connection to an active medical device…”.
As such, the Antimicrobial Nitrile Powder Free Examination Glove is an invasive device intended for short transient use (I. Definitions, 1.1) for examinations on intact skin and also involve body orifices (I. Definitions, 1.2). All other parts of rule 5 do not apply.
Based on rule 5 (III. Classification, section 2, 2.1), the Antimicrobial Nitrile Powder Free Examination Glove is classified as a medical device class I.
Under European Union MDR 2017/745 Annex VIII Rule 14:
All devices incorporating, as an integral part, a substance which, if used separately, can be considered to be a medicinal product, as defined in point 2 of Article 1 of Directive 2001/83/EC, including a medicinal product derived from human blood or human plasma, as defined in point 10 of Article 1 of that Directive, and that has an action ancillary to that of the devices, are classified as class III.
The term liability to act has been removed from MDR, AMG antimicrobial glove will be considered as class III under rule 14 at present.
The second corrigendum of MDR is published to alter Article 120(3) by inserting “…device which is a class I device pursuant to Directive 93/42/EEC, for which the declaration of conformity was drawn up prior to 26 May 2020 and for which the conformity assessment procedure pursuant to this Regulation requires the involvement of a notified body, or which has a certificate that was issued in accordance with Directive 90/385/EEC or Directive 93/42/EEC and that is valid by virtue of paragraph 2 of this Article, may be placed on the market or put into service until 26 May 2024 provided that from 26 May 2020 it continues…”.
In other words, AMG antimicrobial glove may remain or be placed on the market as Class I until May 2024.
The Antimicrobial Nitrile Powder Free Examination Glove is intended to be used in the framework of medical examinations and diagnostic and therapeutic procedures conducted under non-sterile conditions. Furthermore, the use of the device is intended to help prevent cross-contamination.
Its indication is stated as “Any medical condition requiring an examination, a diagnostic or therapeutic procedure on the intact skin or mucosa under non-sterile conditions”.
The Biocides Regulation (EU) No. 528/2012 is not applicable for medical devices unless they are intended to be used for other purposes not covered by the medical device directive, in which case the Biocides Regulation shall also apply to that product insofar as those purposes are not addressed by those instruments. Based on our understanding, this would mean that the biocides regulation is only applicable if the gloves are intended for other non-medical purposes, or the antimicrobial feature would not be within the original purpose of the medical device. As the gloves’ medical purpose is to prevent infection of the patient and the antimicrobial feature supports this purpose, we believe that the biocides regulation is not applicable.