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Medical instrumentation

Powerful disinfectant

Cleaning system for endoscopes will also have applications in the agriculture and the food industries

eduardo cesarEndoscope with illuminated probe: salt-based super-oxidized water acts as a fungicidal and a bactericidal agenteduardo cesar

An endoscope disinfection system based on a water and sodium chloride solution, better known as kitchen salt, is in the final stages of  development  by the Ibasil Tecnologia company, located in São Paulo City’s Butantã neighborhood. This new disinfectant is non-toxic, acts speedily and is environment-friendly. It provides benefits to patients, physicians, and nurses who use endoscopies to control and diagnose diseases of the digestive tract. The innovative system can also be used as a fungicide for fruits and vegetables, as a bactericide in the food industry or as a disinfectant by the poultry and cattle raising industries. The product will be used initially to clean endoscopes, which are put inside the patient’s mouth all the way down to the stomach. This highly complex equipment is equipped with a multitude of channels and valves, thus making it easy for organic and non-organic material to accumulate and act as a possible source of infections by microorganisms. This is why it is necessary to clean endoscopes thoroughly, to avoid the transmission of diseases such as tuberculosis, hepatitis and Aids.

At present, glutaraldehyde at 2% concentration with extra-strength fungicide and bactericide properties is the most commonly used disinfectant in hospitals and clinics. “However, this product is cancer-causing and environment-unfriendly. It takes 30 minutes to disinfect the equipment with glutaraldehyde, whereas our product only takes seven minutes”, says Luís Iba, a director of Ibasil. Studies have shown that the steam released by glutaraldehyde irritates the respiratory tract, can cause rashes, and is toxic to the human organism. This is why in many countries it is being gradually substituted by less aggressive substances.

The project developed by Ibasil was funded by FAPESP’s Programa Inovação Tecnológica em Pequenas Empresas/ Pipe (the Technological Innovation Program for Small Businesses). It is coordinated by chemical engineer, Gerhard Ett, from the Electrocell company, which develops fuel cells for the production of hydrogen-based electric power. Electrocell is based at the Centro Incubador de Empresas Tecnológicas Cietec (Incubator Center for Technological Companies), located at Cidade Universitária, the campus of the University of São Paulo. “Our partnership was the result of our work together, and the cooperation at Cietec ( Ibasil  also began at the same center), coupled with our expertise on automation, systems control and, above all, electrolytic generators whose technology is similar to that of the fuel cells”, says Ett. “These generators transform the salt and water solution into other compounds.” Biologist Debora Moreira, a FAPESP scholarship grantee, is also taking part in the research and development of this product.

The equipment, expected to be available for medical use within one year, is based on an electro-chemical process which generates an electric current from electrolysis in a mixture of water and sodium chloride, a powerful disinfectant comprised of 12 substances. Hypochlorous acid, hydrogen peroxide, chloride oxide and perchloryc acid are the oxidizers with the strongest anti-bacterial action in the mixture, also referred to as super-oxidized water. “One agent increases the action of the other.  Tests have proved that the 12 agents combined have a disinfecting action”, says Iba.

Tests at the HC
The first test to evaluate the super-oxidized water on isolated bacteria from endoscope equipment was conducted at the Endoscopies Service of the Hospital das Clínicas/HC, the teaching hospital at the University of São Paulo/USP Medical School, in August 2006. Samples were collected from six endoscopic instruments used at the HC, after they had been submitted to the water-based mechanical washing process. The collected samples were seeded in the appropriate culture in lab ovens and placed in contact with the super-oxidized water for seven minutes. After this period of time, new samples were collected. The result was that after the contact with the super-oxidized water, various micro-organisms were isolated, such as the Escherichia coli and Pseudomonas aeruginosa bacteria, one of the most prevalent agents in hospital infections. “There was no bacterial growth after  contact with the super-oxidized water”, says Débora Moreira. The next step of the research will focus on an analysis of the efficacy against the hepatitis B and C virus.

Electrodes with a big surface area were built to produce the electro-chemical cell, separated by polymer membranes. “The electro-chemical cell is basically comprised of membranes, anodes and titanium electrodes”, says Gerhard Ett. Two liquids are produced during the electrolysis process. Acid water, the oxidizing disinfectant, is released from one side of the electro-chemical cell, while the other side of the cell releases alkaline water, which is not employed. The two by-products are neutralized before being discarded, in order to prevent any damage to the environment. “Before flowing into the sewer, the disinfectant is mixed with alkaline water, which produces an environment-friendly solution”,  says Iba.

Ibasil had already had some experience in this field before developing the new endoscope disinfecting system. When it was still under incubation at Cietec, from February 2002 to April 2005, the company designed and built an automated endoscope-cleaning equipment called Endolav, the patent and brand name of which were purchased by the Lifemed company in the state of Rio Grande do Sul (see Pesquisa FAPESP nr. 113). At that time, Ibasil began to have closer contact with Electrocell, now participating in the current project.
The next phase of the research will include the participation of the Instituto Biológico do Estado de São Paulo (biological institute), at the Instituto de Tecnologia de Alimentos (food technology institute) and at the Instituto Agronômico de Campinas (agricultural sciences institute) in the bacteriological tests. The researchers want to expand their research studies with the objective of applying this product in the poultry and cattle raising industries. The system can be used to de-contaminate the premises where the animals are kept. It can also be used in meat processing and in disinfecting machines. In farming, the product can be used as a fruit and vegetables fungicide and bactericide and to clean facilities, trucks and machines. The food industry is also a potential user of this product, as it can be used as a disinfectant in the processing of food and fruit juices.

The Project
Automatic disinfecting of endoscopes with electrolytic disinfectant generator based on salt and water (nº 05/55934-1); Modality Programa Inovação Tecnológica em Pequenas Empresas/Pipe; Coordinator Gerhard Ett – Ibasil; Investment R$ 71,241.06 (FAPESP)