Navigation guide deformable at a low voltage

Abstract

The present description relates to a navigation guide for a fluidic circuit, successively comprising a distal part (1), a central part (2) and a proximal part (3), the distal part (1) comprising a substrate (10) having a first main face (10a) covered with one or more active blocks (11) arranged at a first distance from the first end of the distal part (1), and a second main face (10b) covered by one or more active blocks (11) arranged at a second distance from the first end of the distal part (1), the first distance being different from the second distance, whereby the distal part (1) has a non-zero curvature.

Description

DESCRIPTION Low-voltage deformable navigation guide This application is based on, and claims priority from, French patent application number FR 24 / 06500 filed on June 18, 2024, entitled "Low Voltage Deformable Navigation Guide", which is considered to form an integral part of this description within the limits provided by law. technical field

[0001] This description generally relates to devices for navigation in a fluid, for example devices for arterial navigation (endovascular surgery), or for navigation in branching systems such as plumbing pipes or air conditioning circuits. Previous technique

[0002] In endovascular surgery, in order to reach a target blood vessel (such as an artery), surgeons use guides to navigate through the arterial circuit.

[0003] A guide wire connects the target artery with the outside: it allows, for example, the delivery of a balloon catheter and a stent in the case of a stenosis.

[0004] However, since they are not steerable, they must be introduced using pre-formed selective angiography catheters or pre-formed probes. The catheters are chosen according to the shape of the artery: curved, S-shaped, etc. For example, the catheters may be those referenced under the names 'Head Hunter I', 'Cobra I', 'Simmons Sidewinder 2', 'Vertebral', 'Berenstein', 'Multipurpose A'. There is no universal navigation guide: a catheter corresponds to a shape.

[0005] Target artery anchoring is a critical step, particularly in minimally invasive surgery (MIS). Even experienced surgeons typically require several attempts before successfully anchoring an artery (i.e., successfully inserting the guidewire from one artery into another). Such attempts increase operating time and / or the risk of injury and can lead to postoperative complications.

[0006] To facilitate hooking, a guidewire with a slightly curved overhang (between 30° and 50°) can be used, forming a hook. This allows the selective angiography catheter to reach the target artery, and the curvature of the guidewire enables hooking. The drawback of the hook is that its curvature is not adjustable. This hook shape makes advancing the device through the vascular system more difficult, especially when the guidewire is moving against the flow. Furthermore, if the angle between the two arteries is too large and the hook angle is too small, hooking the target artery becomes very difficult.

[0007] To overcome this drawback, devices incorporating an electroactive polymer-based active block have been designed. For example, in the article by Q. Jacquemin et al. ("Design of a new electroactive polymer based continuum actuator for endoscopic surgical robots," 2020, IEEE / RSJ International Conference on Intelligent Robots and Systems (IROS)), the actuator's active block is positioned on a 25µm thick PEN substrate, and the electrodes are made of PEDOT:PSS and the 6µm electroactive polymer layer is made of P (VDF-TrFE-CTFE). By applying voltages greater than 50V / µm, it is possible to bend the device proportionally to the applied electric field. The device is 5 cm long and 4 mm wide.

[0008] Thus, it would be possible to manufacture a navigation guide comprising a substrate covered by an active block. When a voltage is applied to the active block, it deforms mechanically and causes the substrate to bend.

[0009] However, such devices are still too bulky for arterial navigation. Furthermore, the device can be either straight or curved in only one direction, which is not conducive to navigation in structures with complex geometries (particularly those with passages where the device must be oriented in one direction and then the other). In addition, this type of device has a single curvature, which serves both for navigation and for anchoring to the artery.

[0010] Ultimately, the tensions applied to modify the shape of the end are still too high. Summary of the invention

[0011] There is a need for a device whose shape can be changed at low voltage, the device must be miniaturizable to be able to navigate in small fluidic systems, for example in blood vessels of the brain.

[0012] This goal is achieved by a fluidic circuit guide comprising successively a distal part, a central part, and a proximal part, the distal part comprising a first end and a second end in contact with the central part, the distal part comprising a substrate of which a first principal face is covered by a first active block or by a first group of active blocks and of which a second principal face is covered by a second active block or by a second group of active blocks, each active block comprising at least one electroactive layer, a first electrode and a second electrode, the first active block or the first group of active blocks being disposed at a first distance from the first end of the distal part and the second active block or the second group of active blocks being disposed at a second distance from the first end of the distal part, the first distance being different from the second distance, whereby the distal part has a non-zero curvature.

[0013] According to a particular embodiment, the active blocks comprise between 1 and 15 electroactive layers, preferably between 1 and 10 electroactive layers.

[0014] According to a particular embodiment, the electroactive layers of the active blocks are made of polymer, for example a piezoelectric polymer, an electrostrictive polymer or a ferroelectric polymer, of ceramic, for example PZT or SBN, or a composite material comprising a polymer matrix and ceramic particles.

[0015] According to a particular embodiment, the electroactive layers are made of PVDF or one of its copolymers or terpolymers, such as P(VDF-TrFe) or PVDF-TrFE-CFE.

[0016] According to a particular embodiment, the electroactive layers have a thickness of between 3 and 50 pm, preferably between 3 and 10 pm.

[0017] According to a particular embodiment, the substrate is made of polyimide.

[0018] According to a particular embodiment, the first electrodes and the second electrodes are made of an electrically conductive polymer, preferably PEDOT-PSS.

[0019] According to a particular embodiment, the first distance and / or the second distance are between 0 and 15 cm, preferably between 1 mm and 3 cm.

[0020] According to a particular embodiment, the active blocks of the first group of active blocks are identical or different from the active blocks of the second group of active blocks, with the active blocks of the first group of active blocks being arranged opposite the active blocks of the second group of active blocks.

[0021] This goal is also achieved by using a navigation guide that includes at least the following steps: - provide a navigation guide as defined previously, the distal part of the guide having a non-zero curvature, in the absence of applied tension, - apply a voltage, preferably between 10 and 200 V / pm, even more preferably between 10 V and 60 V / pm, to the organic electroactive layers, whereby the curvature of the distal part decreases, for example, until it is zero. Brief description of the drawings

[0022] These features and advantages, as well as others, will be described in detail in the following description of particular embodiments, given by way of non-limiting example, in relation to the attached figures, among which:

[0023] Figure 1 schematically represents, in top view, a navigation guide according to a particular embodiment of the invention;

[0024] Figure 2 schematically and in cross-section represents the distal part of a navigation guide comprising a substrate whose main faces are each covered by an active block, according to another particular embodiment of the invention;

[0025] Figure 3 schematically and in cross-section represents the distal part of a navigation guide comprising a substrate one of whose main faces is covered by an active block and the other main face of which is covered by several active blocks, according to another particular embodiment of the invention;

[0026] Figure 4 schematically and in three dimensions represents the distal part of a navigation guide comprising a substrate whose main faces are covered by several portions of active blocks, according to another particular embodiment of the invention;

[0027] Figure 5 schematically and in cross-section represents the distal part of a navigation guide comprising a substrate whose main faces are covered by several portions of active blocks, according to another particular embodiment of the invention;

[0028] Figure 6 schematically and in cross-section represents the distal part of a navigation guide comprising a substrate whose main faces are covered by several portions of active blocks, according to another particular embodiment of the invention;

[0029] Figure 7 schematically and in cross-section represents the distal end of a navigation guide in the absence of applied tension (position 1) and by applying different tensions (position 2 and position 3), according to another particular embodiment of the invention;

[0030] Figure 8A schematically and in cross-section represents the distal end of a navigation guide, curved in the absence of applied tension, according to another particular embodiment of the invention;

[0031] Figure 8B schematically represents the distal end of a navigation guide, curved when tension is applied, according to another particular embodiment of the invention;

[0032] Figure 9A, Figure 9B, Figure 9C and Figure 9D schematically represent different geometries that can be obtained with a distal part of a navigation guide, in the absence of applied tension (Figure 9A) and by applying different tensions (Figures 9B, 9C, 9D) according to different particular embodiments of the invention;

[0033] Figure 10A, Figure 10B, Figure 10C and Figure 10D schematically represent the position and shape of a navigation guide in a fluidic system according to different stages of a navigation process, according to another particular embodiment of the invention.

[0034] The various elements are not necessarily on a uniform scale in order to make the figures more legible. Description of the embodiments

[0035] The same elements have been designated by the same reference numerals in the different figures. In particular, structural and / or functional elements common to the different embodiments may have the same reference numerals and may have identical structural, dimensional and material properties.

[0036] For the sake of clarity, only the steps and elements useful for understanding the implementation methods described have been represented and are detailed.

[0037] Unless otherwise specified, when referring to two connected elements, this means directly connected without any intermediate elements other than conductors, and when referring to two coupled elements, this means that these two elements can be connected or linked through one or more other elements.

[0038] In the description that follows, when referring to absolute positional qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative positional qualifiers, such as the terms "above", "below", "superior", "inferior", etc., or to orientational qualifiers, such as the terms "horizontal", "vertical", etc., unless otherwise specified, it refers to the orientation of the figures.

[0039] When referring to an active or electroactive element, we are referring to an element that can be electrically activated. In particular, under the action of an electric field (application of a voltage, for example), a mechanical deformation of the element is obtained.

[0040] Unless otherwise specified, the expressions "approximately", "roughly", "about", and "on the order of" mean within 10%, preferably within 5%.

[0041] Subsequently, we will describe in more detail the devices for arterial navigation; however, the device can be used for any type of navigation in a fluid, for example for navigation in various branched systems (plumbing pipe or air conditioning circuit for example).

[0042] We will now describe the navigation guide in more detail with reference to the attached figures.

[0043] As shown in Figure 1, the navigation guide comprises three main parts: the distal part 1 (also called the end), the transition zone 2 (also called the junction, central part or core) and the proximal part 3 (also called the body).

[0044] The distal part 1 comprises a first zone, called the actuator zone, and a second zone 1b, called the overhang zone (or simply overhang or hook). The actuator zone 1a is positioned between the transition zone 2 and the overhang 1b.

[0045] The actuator zone la is connected and electrically linked to the guidewire body 3 by a junction 2. The overhang 1b and the actuator part la are controllable parts. The overhang 1b is an extension of the actuator zone la. The overhang zone 1b is controlled by a person (a surgeon, for example) and can be bent at will, in either direction, to facilitate hooking, for example, with a target artery. The guidewire thus allows easier navigation from one artery to another thanks to the distal end 1, which can be oriented under the influence of an electric field. It is also possible to have an overhang 1b that is not electrically connected and therefore not controllable. In this case, it permanently retains a hooked shape.

[0046] The distal part 1 comprises two ends: one end is free. In other words, it is not connected to any other elements. The second end is in contact with the central part 2.

[0047] As shown in Figures 1 to 6, the distal end 1 comprises a substrate 10 having a first principal face 10a and a second principal face 10b.

[0048] The two main faces are parallel or nearly parallel to each other. The substrate comprises two lateral faces connecting the two main faces.

[0049] The substrate is, for example, a film.

[0050] The first main face 10a of the substrate 10 is covered by a first active block 11 or by a first group of active blocks 11. The second face 10b of the substrate 10 is covered by a second active block 11 or by a second group of active blocks 11.

[0051] The active blocks 11 are also called electroactive blocks. Each active block 11 can comprise one or more active layers 103 (or electroactive layers). In other words, an active block 11 corresponds to one or more 'stacks', each 'stack' being formed by a unitary stack comprising an active layer 103 arranged between two electrodes.

[0052] The first active block 11 or the first group of active blocks 11 is at a first distance dl from the end of the distal part 1 and the second active block 11 or the second group of active blocks 11 is at a second distance d2 from the end of the distal part 1. The first distance dl is different from the second distance d2.

[0053] One of the first distance dl or the second distance d2 is greater by at least 10% and preferably by at least 50% than the other of the first distance dl or the second distance d2.

[0054] Preferably, the first distance dl and / or the second distance d2 are between 0 and 15 cm, preferably between 1 mm and 15 cm, even more preferably between 1 mm and 3 cm, and most preferably between 0.5 and 1.5 cm. At least one of the first or second distances is strictly greater than 0 (i.e., non-zero). Preferably, both distances are strictly greater than 0 to allow for a more flexible overhang for the guide.

[0055] This forms a guide in which the electroactive blocks 11 are arranged asymmetrically on either side of the substrate 10 (with respect to the plane of the substrate 10).

[0056] The offset of the stacks on either side of the substrate 10 means that, in the absence of an electric field, the overhang 1b is curved. Indeed, this geometric asymmetry of the hook 1b induces a prestress in the substrate 10 and therefore a deformation when it is at rest. The prestresses can also be influenced by the difference in thermal coefficient, as well as the evaporation of solvents during the manufacturing process.

[0057] If the stacks were placed opposite each other, on either side of the substrate 10, symmetrically these constraints would cancel each other out and therefore the guide would be flat.

[0058] Thus, the overhang 1b exhibits a non-zero curvature when no tension is applied (position 1 in Figure 7). In particular, the overhang 1b forms an angle 0 Cbetween 20 and 150° with respect to the actuator part la, more preferably between 20° and 100° and even more preferably between 20° and 90°, with the part la (Figure 8A). The actuator part la has a zero angle with respect to the junction part 2 (in other words, the actuator part is not curved).

[0059] When a voltage is applied to the active blocks 11 (i.e., to the organic electroactive layers 103), the substrate 10 is mechanically deformed, creating areas of tension and compression on the faces 10a, 10b of the substrate 10, which leads to a change in the radius of curvature.

[0060] When a tension is applied to the overhang 1b, it straightens (in the opposite direction to the prestress). The curvature decreases until it is zero (position 2, figure 7) or even until it changes direction for stronger fields, i.e. the sample bends in the other direction (position 3, figure 7).

[0061] The controllable lb overhang can take all positions between positions 1 and 3, passing through position 2.

[0062] The end of the guide can therefore be oriented in two directions: the bending can be done in one direction or the other.

[0063] When a voltage is applied in the actuator part la, the actuator part la bends and forms an angle 0a with the junction 2 (figure 8B).

[0064] The presence of multiple active PN block sections allows, by applying tension to the active blocks, the formation of larger angles between the distal portion 1 and the guide body 3, and / or the creation of various deformation configurations for the distal portion 1. The actuated length is adjustable. This can be particularly advantageous when navigating a complex fluidic system with both curved and straight sections.

[0065] An active block portion corresponds to a segment of the distal part 1 on which there may be 1 or 2 active blocks (either on face 10a or on face 10b of the substrate or on both).

[0066] For example, when the device includes several PN portions of active blocks, the distal part 1 of the guide (in particular the overhang 1b) is curved (Figure 9A). By applying electrical voltages to the actuator area, it is possible to modify the shape of the guide as shown in figures 9B, 9C and 9D.

[0067] This type of control is particularly advantageous since the applied voltages allow several (for example two) different curvatures to be generated consecutively.

[0068] Even though a portion of active PN blocks can be activated in both directions, it is possible to connect or activate only one of the two sides depending on the use of the guide.

[0069] The voltage applied to each active block 11 is preferably between 10 V / pm and 200 V / pm, and preferably between 10 V / pm and 100 V / pm. It may be less than 60 V / pm. Such voltages are sufficient to modify the shape of the distal part 1, that is, to bend the part 1a for navigation, and to straighten or even reverse the curve of the overhang 1b.

[0070] We will now describe the different elements of the device in more detail.

[0071] As previously stated, at least one active block 11 is arranged on each side of the substrate 10.

[0072] According to an alternative embodiment, shown in Figure 2, a single active block 11 is disposed on the first face 10a of the substrate 10 and a single active block 11 is disposed on the second face 10b of the substrate 10. The active blocks 11 are offset from each other, so as not to be at the same distance from the first end of the distal part 1.

[0073] According to another embodiment, shown in Figure 3, a single active block 11 is arranged on the first face 10a of substrate 10 and several active blocks 11 are arranged on the second face 10b of substrate 10.

[0074] According to another embodiment, shown in Figures 4 to 6, each of the faces 10a, 10b of the substrate 10 is covered by several active blocks 11. According to this variant, the second distance d2 corresponds to the distance between the active block 11 of the second face 10b closest to the first end of the distal part 1 and the first end of the distal part 1.

[0075] According to this variant, the first distance dl corresponds to the distance between the active block 11 of the first face 10a closest to the first end and the first end of the distal part 1. Also according to this variant, the second distance d2 corresponds to the distance between the active block of the second face 10b closest to the first end of the distal part 1 and the first end of the distal part 1.

[0076] Active blocks 11 can be arranged as portions of active blocks PN (at least two), each portion of active blocks PN comprising at least one active block 11. In other words, a portion of active blocks PN can include: - a single active block 11, or - two active blocks 11, each active block 11 being positioned on either side of the substrate 10, on each of the faces 10a and 10b: a portion PN then comprises two active blocks 11 arranged opposite each other.

[0077] For example, as shown in Figure 4, the device comprises 4 active block portions: P1, P2, P3, and P4. Each active block portion comprises one active block 11 arranged on either side of the substrate.

[0078] The guide can include between 2 and 5 active block segments. "Between X and Y" here and thereafter means that the boundaries are included.

[0079] It is possible to position the majority of the active blocks 11 of the different PN portions on the same side of the substrate to increase the angle between part 1a and part 1b.

[0080] The active blocks 11 of the different portions PN can be arranged, randomly or regularly, on the two faces 10a, 10b of the substrate 10.

[0081] The 11 active blocks can be operated independently of each other.

[0082] The substrate 10 is a flexible substrate, meaning it can deform when the piezoelectric stack is subjected to a voltage. The material is chosen to allow for reversible deformation.

[0083] The substrate 10 is, for example, a polymer such as polyimide (PI) or poly(ethylene naphthalate) (PEN). It can also be a polyarylate (PAR). It could also be a natural, bio-based material.

[0084] The substrate 10 has a thin profile, typically between 15 µm and 1 mm, preferably between 15 µm and 75 µm, and even more preferably between 20 µm and 50 µm, for example 25 µm. With such thicknesses, the substrate can be easily deformed while still supporting the electroactive stack(s) and / or allowing navigation within the target fluidic circuit.

[0085] For arterial navigation, the substrate 10 has a length, for example, between 10 and 100 mm, preferably between 15 and 60 mm, particularly for a device with a single electroactive block. For navigation in For plumbing or air conditioning circuits, the dimensions will be adapted to those of the pipes / circuits.

[0086] The substrate 10 has a width, for example, between 0.1 mm and 5 mm, preferably between 0.2 and 3 mm. For navigation in plumbing or air conditioning circuits, the dimensions will be adapted to those of the pipes / circuits.

[0087] The length / width ratio is preferably between 2 and 150, even more preferably between 5 and 100, for example between 50 and 100. The higher the ratio, the lower the tension required to deform the substrate 10 of the distal part 1.

[0088] The distance 'li' between two consecutive portions of active blocks PN and PN-1 is, for example, between 0.1 and 5 mm, preferably between 2 and 4 mm.

[0089] The distal part 1 has a length of, preferably, between 1 and 17 cm, and preferably between 1 and 15 cm, more preferably between 1 and 7 cm, and very preferably between 1 and 4 cm.

[0090] The length of the distal part 1 corresponds to the sum of the lengths of the different active blocks, the different inter-active block distances and the extreme length.

[0091] In the case where the multilayer active block 11 terminates with an electroactive layer, this plays the role of an encapsulation layer and protects the upper electrode.

[0092] Each active block 11 has a length denoted 'la', for example, between 0.5 and 4 cm, preferably between 1.5 and 3 cm.

[0093] Each active block 11 has, for example, a width between 0.1 mm and 3 cm, preferably between 0.1 and 1 mm, and more preferably between 0.2 and 1 mm. With such widths, arterial navigation is possible.

[0094] The different active blocks 11 can have identical or different dimensions, an identical or different number of electroactive layers.

[0095] For example, as shown in Figure 6, the device comprises three portions of active blocks P1, P2, and P3. Portion P1 comprises a single active block, while portions P2 and P3 each comprise an active block 11 arranged on either side of the flexible substrate 10. The first portion of active blocks P1 comprises an active block 11 consisting of one stack (i.e., the active block comprises one electroactive layer 103). The second portion P2 comprises active blocks 11, each with four stacks (i.e., each active block has four electroactive layers). The third portion P3 comprises active blocks 11, each with two stacks (i.e., each active block 11 comprises two electroactive layers). The dimensions (particularly length and thickness) of the active blocks 11 are different in each case.

[0096] Preferably, the active blocks 11 comprise between 1 and 15 electroactive layers 103, and even more preferably between 1 and 10 layers 103 and even more preferably between 4 and 8 electroactive layers 103. When the active block 11 comprises several electroactive layers 103, the active block 11 is formed of a stack comprising an alternation of electroactive layers 103 and electrodes 101, 102. The stack begins with a first electrode 101 and ends with a second electrode 102, except in the case where a dielectric layer is used as encapsulation.

[0097] When the active block 11 comprises a single active layer 103, this is arranged between a first electrode 101 and a second electrode 102.

[0098] When the active block 11 comprises several electroactive layers 103, it also comprises several first electrodes 101 and several second electrodes 102. The first electrodes 101 and the second electrodes 102 are positioned on either side of each electroactive layer 103. The active block 11 is formed of an electroactive stack.

[0099] Each electroactive layer 103 has a thickness 'ed', for example, between 1 and 50 pm, preferably between 3 and 15 pm, preferably between 3 and 10 pm. With such thicknesses, the applied voltages can be relatively low.

[0100] Electroactive materials are materials that deform under the application of an electric field.

[0101] The electroactive material can be chosen, for example, from polymers (conductive, piezoelectric, ferroelectric, electrostrictive, ionic, etc.), ceramics (notably lead zirconate titanate (PZT) or Sr-Ba-Nb oxide (SBN)), shape memory materials, and rheological fluids. It can also be a composite material, for example, a polymer material containing ceramic particles (notably PZT or BaTiOs particles).

[0102] Preferably, each electroactive layer 103 is an organic electroactive layer. Each electroactive layer preferably comprises a polymer matrix of PVDF, a PVDF copolymer, or a PVDF terpolymer. This may be a copolymer of vinylidene fluoride and at least one other monomer copolymerizable with VDF. Advantageously, the copolymer comprises at least 50 mol%, preferably at least 70% by weight, even more preferably at least 80% by mole of VDF.

[0103] For illustrative purposes, the copolymerizable monomer(s) are, for example, chosen from chlorotrif luoroethylene (CTFE), chlorof luoroethylene (CFE), hexaf luoropropylene (HEP), trif luoroethylene (VFa), methyl methacrylate (MMA), tetraf luoroethylene (TFE), and perfluoro (alkyl vinyl) ethers such as perfluoro (methyl vinyl) ether (PMVE).

[0104] For example, the copolymer is a copolymer of poly(vinylidene fluoride-trifluoroethylene) PVDF / TrFe, also noted as P(VDF-TrFe) or PVDF-CTFE.

[0105] It can also be a terpolymer. For example, a PVDF / TRFE / CTFE or PVDF / TRFE / CFE terpolymer would be chosen. Such materials are called electrostrictive materials.

[0106] According to another embodiment, the polymer is not a ferroelectric polymer: it may be PVDF-HFP.

[0107] In particular, one can choose a piezoelectric material (such as P(VDF-TrFE) ) or an electrostrictive material (such as PVDF-TrFE-CTFE ).

[0108] As previously mentioned, the organic electroactive layer 103 can be a composite material. For example, the layer may include, in addition to the polymer matrix, ferroelectric particles and, possibly, PEDOT:PSS particles to increase the relative permittivity of the material and thus improve its electrical behavior.

[0109] For example, ferroelectric particles are made of BaTiO₂ (BTO), PZT (lead zirconate titanate), AIN, ZnO, or SBN. (Sr-Ba-Nb oxide) or SBT (Sr-Ba-Ti oxide). Such particles are used, for example, with a crosslinkable epoxy matrix. This gives the layer a certain stiffness, which allows for the efficient conversion of electrical impulse into mechanical displacement.

[0110] Electrodes 101, 102 have, for example, a thickness 'ec' between 0.1 and 10 pm, preferably between 0.1 and 3 pm, even more preferably between 1 and 2.5 pm.

[0111] Preferably, electrodes 101, 102 are made of an electrically conductive polymer, preferably PEDOT-PSS (poly(3,4-ethylenedioxythiophene).

[0112] The materials forming the different active blocks 11 may be identical or different. Preferably, they are identical. Even more preferably, each active block 11 comprises electrodes 101, 102 made of PEDOT-PSS and an electroactive layer made of P(VDF-TrFe), the whole being optionally covered by an encapsulation layer.

[0113] When using the navigation guide, depending on the desired shape, it is possible to apply no tension, or to apply one or more different tensions to the active blocks 11. With such a device, it is possible to have an end curved in one direction or the other, a straight shape or an S-shaped end.

[0114] According to one embodiment, each part of the navigation guide includes a substrate to support different elements (electrical tracks, electrical wires, active blocks).

[0115] Preferably, the guide body can be made of wires, possibly coated in a polymer material.

[0116] In cases where electrical traces are used, the proximal portion 3 (also called the body) and the transition zone 2 (also called the core) each comprise a substrate. The substrate of the proximal portion 3 and the substrate of the transition zone 2 may be the same or different. These substrates are preferably made of a polymer such as PEN or PI. The thickness of these substrates is, for example, between 25 and 250 µm.

[0117] The substrate 10 of the distal part 1 is advantageously thinner than those of the central part 2 and proximal part 3 in order to be more easily deformed. According to another embodiment, the substrate 10 of the distal part 1 may have the same thickness as those of the central part 2 and proximal part 3.

[0118] Electrical connection means are arranged to carry the signal to the active blocks 11 positioned at the distal part 1.

[0119] Several solutions can be considered to route the electrical signal in body 3 of the navigation guide and / or in core 2 of the navigation guide.

[0120] According to a first embodiment, the connection is made using electrical wires (i.e., electrically conductive wires). The wires are, for example, in an electrically insulating sheath. The wires can be braided or positioned concentrically.

[0121] In another embodiment, the connection is made using electrical tracks (i.e., electrically conductive tracks). The tracks can be printed or deposited onto the substrate by another method (e.g., photolithography). The tracks can be arranged on one side of the substrate or on both sides.

[0122] The tracks can be made of a metal (gold or silver, for example) or an electrically conductive polymer material. For example, the electrically conductive polymer material is PEDOT:PSS. It can also be a polymer in which electrically conductive particles are dispersed, for example, carbon or gold particles. Advantageously, the particles have a larger dimension than 300 nm to avoid increasing roughness.

[0123] Several configurations are possible, in order to connect the electrical tracks and / or electrical wires.

[0124] For example, it is possible to cover part of the lower electrode (the one in contact with the substrate) with one of the electrical tracks.

[0125] Electrical tracks and / or electrical wires can be connected to the lower electrode of an active block by means of an electrically conductive adhesive (e.g., filled epoxy) or by means of a weld.

[0126] Optionally, an electrically conductive plate (for example made of metal, especially copper) can be positioned on the substrate, glued or welded to the lower electrode on one side and glued or welded to the electrical wire or electrical track on the other.

[0127] According to another embodiment, mechanical systems such as clips or rivets can be used to connect the electrode of the active block to the wire or track.

[0128] The various connections can be covered by a cover. In particular, it is possible to use an electrically conductive cover. For example, the cover can to understand nanoparticles. The hood allows to plug any holes and / or to prevent breakdown phenomena.

[0129] It is also possible to increase the stiffness of the central core 2 by locally adding an additional layer to the substrate. For example, this could be a polymer layer. The polymer may be the same as or different from the substrate polymer. It could also be a metallized polymer layer. Polymer layers can be deposited by bonding. Welding can also be used. Alternatively, the additional layer could be a dielectric layer, for example, screen-printed. It could also be a metallic foil. The foil can have a thickness between 10 and 1000 µm, preferably between 10 and 100 µm. The foil can be made of zinc or aluminum.

[0130] The connections between electrodes 101 and electrodes 102 can be shared to reduce the number of electrical traces / wires. This minimizes the space required for connections and thus reduces the substrate width.

[0131] Preferably, the distal end 1 is covered by an encapsulation layer. The encapsulation layer surrounds the different portions of active blocks. The encapsulation layer can be made of a polymer material, for example, an epoxy, polydimethylsiloxane (PDMS), poly(methyl methacrylate) (PMMA), polyvinylidene fluoride (PVDF) or one of its derivatives.

[0132] Even more preferentially, the distal end 1, the central core 2 and at least part of the body 3 are covered by the encapsulation layer.

[0133] Encapsulation can be achieved by dipping, thermal evaporation, or spraying. solution. The encapsulation step is advantageously carried out once the electrical connections have been made.

[0134] Radio-opaque elements can be added to the device, for example, to the flexible substrate or the encapsulation layer, between portions of active blocks, to enable visual tracking of navigation within the target system. These elements can take the form of crosses, squares, dots, lines, or bands.

[0135] The navigation guide can be up to, for example, 180 cm or even 300 cm long.

[0136] The distal part 1 can be made in the following way: a) deposit at least one electrically conductive area on each face of a substrate 10, to form a first electrode 101, b) form an electroactive layer 103 on each electrically conductive area, c) form a second electrode 102 on each electroactive layer 103.

[0137] Alternatively, it is possible to form the active block(s) 11 on one face of the substrate 10, and then to form the active blocks 11 on the other face of the substrate 10.

[0138] In step b), the electroactive material layer can be deposited by spin coating. Other types of localized deposition can be used, such as screen printing, spraying, dispensing, or even inkjet deposition. Preferably, the electroactive layer is deposited by screen printing. In a single pass, the deposited thickness is between 1 and 20 µm. It is possible to superimpose several layers by screen printing until the final desired thickness for the electroactive layer 103.

[0139] For the active blocks 11, advantageously, between 1 and 10 layers of composite will be deposited between the electrodes 101, 102, according to the following sequence: N x (electrode 101 / composite 103 / electrode 102). The number of deposited layers depends on the dielectric thickness.

[0140] Steps a), b) and c) are repeated to form the stack, with step a) being repeated, not on the substrate, but on the underlying electroactive layer.

[0141] The process also includes a crystallization step of the electroactive layer to improve its performance. This irradiation is carried out, for example, with a UV flash light, with a flash duration, or pulse duration, of approximately 500 ps to 2 ms, and a fluence (energy delivered per unit area) of approximately 15 J / cm². 2 and 25 J / cm² 2 and with light of wavelength between approximately 200 nm and 380 nm. The number of UV light flashes, or pulses, produced during this irradiation varies depending on the thickness to which the material is to be crystallized. For example, for a P(VDF-TrFe) thickness of approximately 2 pm, the irradiation can be carried out with a fluence of approximately 17 J / cm². 2 , a pulse duration of approximately 2 ms and a number of pulses of 5.

[0142] The material, possibly having undergone prior crystallization, is then subjected to annealing, for example, at approximately 130°C for about 60 minutes, to complete the total crystallization of the material. Annealing can be carried out at ambient pressure or at low pressure.

[0143] The crystallization of the material can therefore be carried out in two stages: first, pulsed irradiation UV light to properly crystallize the second side of the layer in material in order to increase its thermal conductivity, then thermal annealing completing the crystallization for the rest of the material not crystallized by the previous irradiation.

[0144] When the material is a P-based copolymer (VDF-TrFe), a material polarization step is performed before use. This step can be carried out, for example, by applying a direct current (DC) voltage across its terminals via electrodes to improve the material's coefficient. This polarization is performed only once for the entire lifespan of the material. This AC and / or DC polarization can be done at room temperature or under heat (up to approximately 100°C). For example, it is possible to perform AC polarization followed by DC polarization. When polarization is performed at room temperature, it is possible to apply a DC voltage of up to approximately 150 V / m or even 200 V / m of electroactive layer thickness for a duration ranging from a few seconds to a few minutes.For example, a voltage of 120 V / pm will be applied for 20 seconds. When hot polarization is performed, for example at a temperature of approximately 90°C, a DC voltage, for example, between approximately 50 V / pm and 80 V / pm, can be applied to the dielectric layer for a duration, for example, between approximately 1 and 5 minutes. The temperature is then lowered to ambient temperature, and the electric field applied to the material via the applied DC voltage is then switched off. Such polarizations allow PVDF to achieve remanent polarization values ​​of 8 pC / cm. 2 . Tl

[0145] The dipoles within the layer remain oriented in this way, even when the material is no longer subjected to this electric field. The material can thus be polarized by applying an initial polarization voltage across the electrodes. A piezoelectric material thickness of between 3 and 4 µm is preferably chosen to promote polarization of the piezoelectric material by this capacitance, and the level of the applied voltage between the electrodes is also chosen to achieve the initial polarization of the piezoelectric material (when the piezoelectric material must be initially polarized).

[0146] Annealing is advantageously carried out at the end of the process, or between the different stages. Annealing is, for example, at a temperature between 100°C and 150°C, preferably around 100°C to remove residual traces of solvent and / or finalize the crystallization of the piezoelectric material.

[0147] Annealing can be carried out under vacuum. For example, a vacuum on the order of mbar. The annealing time, for mbar, can be at least 1 minute, preferably 3 minutes.

[0148] At the end of the process, contact is advantageously resumed in order to connect the active blocks 11 of the distal part 1 to the core 2 and to the proximal part 3 of the navigation guide.

[0149] To navigate within a fluidic system, the guide manipulation process may include the following steps: - apply tension on the guide in order to reduce the curvature of the distal part, or even to make it flat (figure 10A); - to advance the guide through the first channel, by example by pushing it, until it passes an intersection with a target pipe; decrease the applied tension, stop applying tension or increase the applied tension to bend the distal part (figure 10B); - pull on the guide until it reaches the intersection with the target pipe (figure 10C); - insert the guide into the target pipe; - modify the tension applied to the guide in order to reduce the curvature of the distal part, or even to make it flat (figure 10D); - advance the guide into the target pipe, for example by pushing it.

[0150] Pipes can be arteries, plumbing conduits, printed air circuits, etc.

[0151] Various embodiments and variations have been described. A person skilled in the art will understand that some features of these various embodiments and variations could be combined, and other variations will become apparent to a person skilled in the art.

[0152] Finally, the practical implementation of the described methods and variants is within the reach of the person in the trade, based on the functional indications given above.

Claims

DEMANDS 1. Navigation guide for a fluidic circuit comprising successively a distal part (1), a central part (2) and a proximal part (3), the distal part (1) comprising a first end and a second end in contact with the central part, the distal part (1) comprising a substrate (10) comprising two principal faces (10a, 10b), the first principal face (10a) being covered by a first active block (11) or by a first group of active blocks (11), the second principal face (10b) being covered by a second active block (11) or by a second group of active blocks (11), each active block (11) comprising at least one electroactive layer (103), a first electrode (101) and a second electrode (102),the first active block (11) or the first group of active blocks (11) being disposed at a first distance from the first end of the distal part (1) and the second active block (11) or the second group of active blocks (11) being disposed at a second distance from the first end of the distal part (1), the first distance being different from the second distance, whereby the distal part (1) exhibits a non-zero curvature in the absence of applied tension.

2. Navigation guide according to claim 1, characterized in that the active blocks (11) comprise between 1 and 15 electroactive layers (103), preferably between 1 and 10 electroactive layers (103).

3. Guide according to any one of claims 1 and 2, wherein the electroactive layers (103) of the active blocks (11) are in polymer, for example in a piezoelectric polymer, an electrostrictive polymer or a ferroelectric polymer, in ceramic, for example in PZT or SBN, or a composite material comprising a polymer matrix and ceramic particles.

4. Guide according to the preceding claim, wherein the electroactive layers (103) are made of PVDF or one of its copolymers or terpolymers, such as P(VDF-TrFe) or PVDF-TrFE-CFE.

5. Navigation guide according to any one of the preceding claims, characterized in that the electroactive layers (103) have a thickness between 3 and 50 pm, preferably between 3 and 10 pm.

6. Navigation guide according to any one of the preceding claims, characterized in that the substrate (10) is made of polyimide.

7. Navigation guide according to any one of the preceding claims, characterized in that the first electrodes (101) and the second electrodes (102) are made of an electrically conductive polymer, preferably PEDOT-PSS.

8. Navigation guide according to any one of the preceding claims, wherein the first distance and / or the second distance are between 0 and 15 cm, preferably between 1 mm and 3 cm.

9. Navigation guide according to any one of claims 1 to 8, characterized in that the active blocks (11) of the first group of active blocks (11) are identical to or different from the active blocks (11) of the second group of active blocks (11), and from the active blocks (11) of the first group of blocks active (11) being arranged opposite active blocks (11) of the second group of active blocks (11).

10. A method for using a navigation guide comprising at least the following steps: - to provide a navigation guide as defined in one of the preceding claims, the distal part (1) of the guide having a non-zero curvature, in the absence of applied tension, - apply a voltage, preferably between 10 and 200 V / pm, even more preferably between 10 V and 60 V / pm, to the organic electroactive layers (103), whereby the curvature of the distal part (1) decreases, for example, until it is zero.

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