Gasplasma Sterilization

Dr.T.V.Rao MD

GASPLASMA

STERILIZATION NEWER TECHNOLOGIES

DR.T.V.RAO MD 1

ADVANCES IN STERILIZATION

• Sterilization, as a specific discipline, has been with us for approximately 120 years, since the invention of the steam autoclave by Charles Chamberland in 1879.1 Since that time, we have seen progressive refinement in steam sterilizers: from the early, manually operated equipment to modern microprocessor-controlled, automatic machines. Although the efficiency, reliability, and performance monitoring of modern equipment is continually improving, the fundamental process remains essentially the same.

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• Gas Plasma (vaporized

hydrogen peroxide) is a

relatively new option that

can provide low heat

sterility cycles with none of

the off-gassing concerns

present with EtO. Gas

Plasma (VHP) sterilization

has, until now, been

exclusively used by large

manufacturers as the end

line process for in-house

sterilization.

GAS PLASMA

DR.T.V.RAO MD 3

• Who Found It? First

discovered by Sir

William Crookes, in

1879 But it wasn‟t

called „plasma‟ until

1928, when Irving

Langmuir coined the

term

WHO FOUND IT?

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PLASMA STERILIZATION

• A plasma is a quasi-neutral collection of electrons, positive ions, and neutrals capable of collective behavior

• Positive ions = free radicals

• Plasma sterilization operates synergistically via three mechanisms:

• Free radicals interactions

• UV/VUV radioactive effects

• Volatilization

• Dead microorganisms = sterilization

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• UV/VUV radiation

causes

• formation of thymine

dimers in DNA,

inhibiting bacterial

replication.

• Base damage

• Strand breaks

PLASMA STERILIZATION MECHANICS: IR

(NUCLEIC ACID VIEW), UV RADIATION

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• Gas plasma

sterilization

technology based

of Plasma was

patented in 1987,

and marketed in

U S 1993.

BEGINNING OF GAS PLASMA

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• Yes.

• Plasmas are currently

employed in many

industries to accomplish

both highly effective, and

delicate sterilization.

• Not future technology!

Plasmas are used today!

• But, how do they work?

CURRENT STERILIZATION

MEANS: PLASMAS?

• Plasma is a fourth state of matter which is distinguishable from liquid, solid, or gas. In nature, plasma is widespread in outer space.

• Gas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

WHAT IS GAS PLASMA

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HOW GAS PLASMA WORKS.

• Many particles are in the form of free radicals

• A free radical is an Atom with an unpaired electron and

is a highly reactive species

• The mechanism of action of this device is the

production of free radicals within a plasma field that

are capable of interacting with essential cell

components, ie is enzymes and nucleic acids. And

thereby disrupt the metabolism of microorganisms.

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BASIC MECHANISMS OF PLASMA

STERILIZATION

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• A-Destruction by UV irradiation of the genetic material of the

microorganism; this is a statistical process requiring a sufficient

number of lesions of the DNA strands.

• B- Erosion of the microorganism, atom by atom, through intrinsic

photo desorption Photon-induced desorption results from UV

photons breaking chemical bonds in th microorganism material

and leading to the formation of volatile compounds from atoms

intrinsic to the microorganism. The volatile by-products of this

nonequilibrium chemistry are small molecules (e.g., CO and

CHx)

BASIC MECHANISMS OF PLASMA STERILIZATION

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• Erosion of the microorganism, atom by atom, through

etching. Etching stems from the adsorption of reactive

species from the plasma (glow or afterglow) on the

microorganism with which they subsequently undergo

chemical reactions to form volatile compounds

(spontaneous etching). The reactive species can be atomic

and molecular radicals, for example, O and O3,

respectively, and excited molecules in a metastable state,

for example, the O2 singlet state all spores are ultimately

inactivated by UV photon irradiation of their DNA material

• Materials and device

compatibility

• Rapid turnaround

times

• In-house control of

the sterilization

process

• Lower inventory

requirements.

IDENTIFIED ADVANTAGES

DR.T.V.RAO MD 13

• The advantages of gas

plasma sterilization include

its ability to provide safe,

non toxic, dry, low-

temperature sterilization in

about one hour. By-

products of plasma

sterilization are primarily

water and oxygen. Because

these by-products are

harmless, there is no need

for aeration or

environmental hazard

concerns.

BENEFICIAL FOR STERILIZING TEMPERATURE-

SENSITIVE POLYMERIC MATERIALS

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STEPS IN PLASMA STERILIZATION • The Vacuum Phase

• The chamber is evacuated, reducing internal pressure in preparation

for the subsequent reaction.

• The Injection Phase

• A measured amount of liquid peroxide is injected into the chamber, evaporating the aqueous hydrogen peroxide solution and dispersing it into the chamber, where it kills bacteria on any surface it can reach.

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• The hydrogen peroxide

vapour permeates the

chamber, exposing all load

surfaces to the sterilant and

rapidly sterilizes devices

and materials without

leaving any toxic residues.

At the completion of this

phase, the chamber

pressure is reduced and

the plasma discharge is

initiated.

THE DIFFUSION PHASE

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THE PLASMA PHASE

An electromagnetic field is created in which the hydrogen peroxide vapour breaks apart, producing a low-temperature plasma cloud that contains ultraviolet light and free radicals. Following the reaction, the activated components lose their high energy and recombine to form oxygen and water. Phases 1, 2, and 3 are then run a second time for added efficacy. This built-in reprocessing assures optimal sterilization for even the most difficult-to-sterilize devices.

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The chamber is vented to equalize the pressure enabling the chamber door to be opened. There is no need for aeration or cool-down. Devices are ready for immediate use.

THE VENT PHASE

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GRAPHIC REPRESENTATION OF GAS

PLASMA TECHNOLOGY

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PLASMA STERILIZATION

MECHANICS: IR (CELLULAR VIEW)

• IR impacts the cell, three outcomes can result.

• Low-Temperature Hydrogen

Peroxide Gas Plasma

(LTHPGP) has a number of

advantages compared to

established sterilization

technologies. These include a

short (one to four hours)

sterilization cycle, low

temperature and humidity, no

aeration requirement, no toxic

chemical residues or

environmental impact, and broad

compatibility with materials.

ADVANTAGES OF PLASMA

STERILIZATION

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• The Sterrad system offers a

short cycle (averaging 75

minutes), low temperature and

humidity, no aeration

requirement, no chemical

residues, negligible

environmental impact, and wide

compatibility with materials. Its

drawback is an inability to

process liquids, powders, or

strong absorbers (e.g.,

cellulosics).

HYDROGEN PEROXIDE GAS PLASMA.

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THE BIOLOGICAL INDICATOR FOR

QUALITY CONTROL

• The Biological indicator used with system is Bacillus atrophaeus

spores. And Bacillus sterothermophilis

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• The newer version of

unit, which employs

a new vaporization

system that removes

most of the water

from hydrogen

peroxide, has a

cycle time from 28-

38 minutes.

IMPROVEMENT TO NEW

TECHNOLOGY

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The process inactivates

microorganisms primarily

by the combined use of

hydrogen peroxide gas and

the generation of free

radicals ( hydroxyl and

hydroproxyl free radicals )

during the plasma phase of

the cycle.

MODE OF ACTION IN GAS PLASMA

USAGE

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• Materials and devices that cannot tolerate high temperatures and humidity such as some plastics, electrical devices, and corrosion- susceptible metal alloys, can be sterilized by hydrogen peroxide

• This method proved compatible with most (>95%) medical devices and materials tested.

USES OF GAS PLASMA IN HOSPITALS

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GAS PLASMA APPARATUS

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GAS PLASMA WORK STATION

• Medical instrumentation can be sterilized through a hydrogen peroxide gas plasma process with the Sterrad 100 system (Advanced Sterilization Products). Photo: Advanced Sterilization Products

DR.T.V.RAO MD 28

DISADVANTAGES OF PLASMA

STERILIZATION

• Weak penetrating power of the plasma species. Complications arise in:

• Presence of organic residue

• Packaging material

• Complex geometries

• Bulk sterilization of many devices

• Solutions: Introduce preferentially targeting UV/VUV radiation of proper wavelength

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• The disadvantages of gas

plasma sterilization are that it

may not penetrate well,

especially in channels or devices

designed with long lumens. In

addition, the gas plasma

sterilization method may corrode

some materials and cannot be

used on paper, cellulose

or linen. An additional

drawback to plasma sterilizers is

their small chamber.

DISADVANTAGES

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ACCEPTABLE TECHNOLOGY

• According to experts, only a few disadvantages

associated with gas plasma sterilization exist.

These include the inability to process liquids,

powders, or strong absorbers (cellulosics), and

some lumen restrictions. Also, gas plasma

sterilization is not recommended for liquids and

other devices that can be damaged physically or

changed by exposure to low pressure.

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• In 1993, the STERRAD

Technology received

clearance and was

introduced into the United

States. It is now available

in more than 60 countries

throughout the world with

over 6,000 units sold,

making it the world's fastest

growing sterilization

technology.

STERRAD TECHNOLOGY

DR.T.V.RAO MD 32

• The STERRAD 100

sterilization system

(Johnson & Johnson

Medical Ltd) uses

low temperature

hydrogen peroxide

gas plasma for

sterilization of heat

labile equipment.

STERRAD 100

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• An important shortcoming

of plasma sterilization is its

dependence on the actual

“thickness” of the

microorganisms to be

inactivated since the UV

photons need to reach the

DNA. Any material covering

the microorganisms,

including packaging, will

slow down the process.

SHORT COMING OF GAS PLASMA

STERILIZATION

DR.T.V.RAO MD 34

GROWING PROBLEM WITH PRIONS

• Prion diseases, or proteinaceous infectious particle only agents, are able to

induce abnormal folding of normal cellular prion proteins in the brain and can

develop into neurodegenerative disorders including Gerstmann-Straussler-

Scheinker Syndrome, fatal familial insomnia and Creutzfeldt-Jakob Disease

(CJD) in humans. Such prion diseases can have long asymptomatic

incubation periods but will result in fatality in all cases. Unlike infectious

agents in other difficult-to-treat infectious diseases, prions exhibit an

unusually high level of resistance to common

sterilization methods and disinfection methods,

including steam, and pose a threat to infection prevention in healthcare

facilities.

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• The effectiveness of low-

temperature STERRAD®

technology against the

prion threat confirmed that

is possible to eliminate

these deadly pathogens

while helping to preserve

the integrity of medical

devices, including heat

sensitive surgical

instruments

STERRAD TECHNOLOGY IS SAFE IN DEALING

IN CONTAMINATION WITH PRIONS

DR.T.V.RAO MD 36

Email

doctortvrao@gmail.com

THE TOPIC CREATED AS PER GUIDELINES

FOR DISINFECTION AND STERILIZATION IN

HEALTHCARE FACILITIES,2008

CDC

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