Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
  • B01J20/26—Synthetic macromolecular compounds
  • B01J20/268—Polymers created by use of a template, e.g. molecularly imprinted polymers
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
  • G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
  • G01N21/78—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator producing a change of colour
  • G01N21/783—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator producing a change of colour for analysing gases
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
  • G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
  • G01N21/7703—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator using reagent-clad optical fibres or optical waveguides
  • G01N2021/7706—Reagent provision
  • G01N2021/773—Porous polymer jacket; Polymer matrix with indicator
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
  • G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
  • G01N2021/7756—Sensor type
  • G01N2021/7763—Sample through flow
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
  • G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
  • G01N2021/7769—Measurement method of reaction-produced change in sensor
  • G01N2021/7786—Fluorescence
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2600/00—Assays involving molecular imprinted polymers/polymers created around a molecular template

Definitions

• the field of the invention is that of chemical sensors and in particular sensors capable of detecting particularly dangerous molecules such as explosives, drugs ...
• a chemical sensor comprises a sensitive layer brought into contact with a transducer which translates the signal chemical generated following interactions between the sensitive layer and the compound to be detected in an easily quantifiable signal.
• An effective chemical sensor must therefore fulfill the following two conditions: being able to easily create interactions with the molecule to be detected and generating an easily observable signal.
• a very large number of technological solutions in the field of gas detection are available today. However, there is not yet a system which combines high selectivity, very high sensitivity and very short response time for the detection of dangerous gases.
• the selectivity is only partial since a priori many molecules of electron deficient type can extinguish (quencher) the fluorescence of the polymer and therefore lead to false alarms.
• quencher quencher
• the potential interferers can be fragrances, some of which are shown below.
• Nitrobenzene a tobacco by-product, can also falsify detections.
• the present invention provides a highly selective chemical sensor combining the detection of molecular entities by a variation in fluorescence and the prior selection of said entities by a chemical filter based on molecularly imprinted material.
• the invention proposes a new concept of sensor in which we associate a material which will sort the molecules ( filter) with a fluorescent material which will act as a sensitive layer. It should also be noted that in this way, the risks of saturation of the sensitive polymer are also limited following the adsorption of interfering molecules.
• the subject of the invention is a chemical sensor intended for the detection of a type of molecule comprising a fluorescent material capable of forming a complex with the type of molecule to be detected and means for measuring the variation in fluorescence of said material, characterized in that it further comprises a filter comprising a polymeric material comprising so-called molecular fingerprint cavities whose geometric and chemical configuration is defined so as to fix only the type of molecule to be detected.
• the fluorescent material may be a polymer or a set of small molecules.
• the fluorescent polymer may be a polymer with a pi-conjugated chain, for example of the type
• the polymer material comprising so-called molecular fingerprint cavities can be obtained from functional monomers capable of complexing the molecule to be detected, the interactions possibly being of the hydrogen bond type,
• the fluorescent material can be deposited in a thin layer on the surface of at least one first substrate.
• the polymer material comprising so-called molecular finger cavities can be produced on the surface of a membrane or on the surface of microbeads so as to provide a maximum exchange surface with the outside and so as to also allow a response time. (adsorption time of molecules to be detected) as short as possible. More precisely, it can be formed on the surface of a membrane or on the surface of microbeads maintained in a porous support, positioned perpendicular to the charged flow or positioned parallel to the gas flow and arranged in a column of the chromatographic column type.
• the senor can comprise a pump for sucking in an external medium charged with the type of molecule to be detected. It can also include a source of inert gas which may be nitrogen, positioned downstream of the pump to transport the molecules to be detected to the polymeric material with cavities. According to the invention, the sensor can also comprise a removable shutter making it possible to separate the polymeric material with cavities from the fluorescent material.
• the means for detecting variation in fluorescence may advantageously comprise a light source for illuminating the fluorescent material and photodetection means for collecting at least part of the light emitted by the complex formed between the fluorescent material and the molecules to be detected, or to measure the decrease in the light emitted by the “raw” material following the adsorption of the molecule to be detected, ie following the formation of the complex.
• the subject of the invention is also a method of chemical detection of a type of molecule by a sensor according to the invention, characterized in that it comprises the following steps: - the capture by selective adsorption of the type of molecules to be detected by the polymer material comprising so-called molecular finger cavities.
• the type of molecules to be detected can be captured with a pump so as to collect a flow external to the sensor loaded with molecules to be detected.
• the method can comprise closing a shutter making it possible to isolate the polymeric material comprising cavities, from the fluorescent material, during the capture operation. It can then also include the opening of the shutter during the desorption operation so as to send the secondary flow loaded with molecules to be detected towards the fluorescent material.
• the sensor according to the invention comprises a filter comprising a molecularly imprinted polymer prepared from the molecule to be detected carried by a support.
• the support may be constituted either by a functionalized membrane or by a set of functionalized microbeads.
• MIPs molecular imprinted polymers
• MIPs Like biological receptors, MIPs benefit from a high affinity and good selectivity for given molecules.
• a priori we can design MIPs in the image of any molecule or family of functional molecules ("molecular mecano"): thus, we can consider the synthesis of "custom" MIPs and more particularly for target molecules for which there is no biological equivalent.
• MIPs Due to their highly cross-linked chemical structure, MIPs exhibit very good thermal and chemical stability. They also have the advantage of being synthesized from low-cost reagents. MIPs can be of different types: organic, organic-inorganic hybrid or inorganic. As summarized in the diagram illustrated in FIG. 1 and described in more detail below, the molecularly imprinted polymer (MIP) is obtained by polymerization, using an initiator, and in the presence of a crosslinking agent d one or more types of polyfunctional monomers (mf) in the presence of a molecule called template (mg) which can be either directly the molecule to be detected, or a steric and chemical analog.
• mf polyfunctional monomers
• the template molecule develops interactions with one or more functional monomers in a pore-forming solvent.
• a crosslinking agent and a polymerization initiator leads to the formation of a synthetic matrix containing the recognition sites specifically built around the template molecule.
• dite dite so-called “extraction” step the template molecule is eliminated using an adequate solvent: a polymer matrix is finally obtained having cavities called imprints, the geometric and chemical configuration of which is perfectly adapted the fixation of molecules of interest.
• the MIP may be a hybrid gel obtained from a mixture of silicon alkoxides such as tetramethoxysilane and methylthmethoxysilane, some of which may be functionalized by organic groups, for example the following alkoxide:
• the hybrid MIP gel can then be obtained by reaction of these monomers by hydrolysis and polycondensation in the presence of water and ethanol (an acidic or basic catalyst can also be added) and in the presence of the molecule said to be printed (in particular, 2,4 DNT, a by-product of the manufacture of TNT with a higher vapor pressure than TNT).
• the chemical sensor according to the invention thus has an upstream part capable of selectively filtering a type of molecules and a downstream part comprising the fluorescent material and thereby sites of formation of complexes capable of creating variations in fluorescence representative of the presence or even the concentration of said molecules in the environment in which the sensor will have been placed.
• the transfer process takes place in four stages: 1) Absorption of a photon of Eo energy by the host 2) Relaxation of the environment of a magnitude such that the energy available for a radiative transition of the host is E ⁇ ⁇ E 0 3) Transfer of the energy Ei to the doping complex / extinction site 4) Return to the ground state by a non-radiative process, which explains the decrease in the fluorescence intensity.
• FIG. 2 illustrates this example:
• a pump P1 supplies the sensor with an external flow F1 of ambient air containing molecules to be detected.
• an upstream chamber is thus formed by closing the shutter Op, so as to isolate the filter from the downstream detection part of the sensor, formed at the level of the fluorescent material.
• an inert gas source typically nitrogen
• a flow F2 which desorbs the molecularly imprinted material and makes it possible to generate a charged inert flow molecules to be detected which are sent to the downstream part of the sensor by opening the shutter Op.
• an inert gas makes it possible to limit the photochemical degradation of the fluorescent polymer.
• An opening 01 is provided to release outside the sensor the inert gas charged with other impurities than the molecules which it is specifically sought to detect. The flow F2 loaded with molecules to be detected is transported to the substrates covered with fluorescent material.
• the latter can typically be deposited on the surface of two substrates (S1, S2) oriented parallel to the direction of the flow F2, so as to optimize the exchange surface between said flow and the sites capable of generating charge transfer complexes within the fluorescent polymer.
• a second opening 02 is also provided in the downstream part of the sensor to allow the evacuation of the flow F2.
• the measurement means comprise a light source SL of laser type or laser diode which can typically emit around 450 nm for the detection of DNT molecules with the fluorescent polymers described above, which irradiates all of the substrates carrying the fluorescent polymer .
• a PhotoMultiplier or CCD type photodetector is placed perpendicular to the light source so as to collect part of the radiation scattered by the polymer charged with molecules to be detected without collecting incident light directly emitted by the source.
• the photodetector can detect wavelengths centered on 530 nm (representative of the energy radiations E1 explained above)

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• Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Analytical Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Plasma & Fusion (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)

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• 2004
  • 2004-02-12 FR FR0401395A patent/FR2866429B1/fr not_active Expired - Fee Related
• 2005
  • 2005-02-09 US US10/589,467 patent/US20070148696A1/en not_active Abandoned
  • 2005-02-09 WO PCT/EP2005/050573 patent/WO2005088279A1/fr not_active Application Discontinuation
  • 2005-02-09 EP EP05716653A patent/EP1714140A1/de not_active Withdrawn

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