WO2011141426A1

WO2011141426A1 - Needle device for detecting biosignals through the skin

Info

Publication number: WO2011141426A1
Application number: PCT/EP2011/057430
Authority: WO
Inventors: Furio Gramatica; Marzia Bedoni; Michele Casella; Domenico Giorgio Cassara'; Elena Forvi; Antonio Michelino Iorio
Original assignee: Tt Seed S.R.L.
Priority date: 2010-05-10
Filing date: 2011-05-09
Publication date: 2011-11-17

Abstract

The object of the present invention relates to a needle device for detecting biosignals through the skin of a mammal comprising an array of needles that extend from a base coupled to a support. Said support is slidingly mounted within a container and is connected to actuating means suitable for moving said support from a non operating position, wherein said array of needles is out of contact with the skin, to an operating position wherein said array of needles is in electric contact with the skin.

Description

NEEDLE DEVICE FOR DETECTING BIOSIGNALS THROUGH THE SKIN

DESCRIPTION

The present invention relates to a needle device used as sensors for detecting bio signals through the skin.

In the clinical field, biomedical sensors are used for detecting biosignals acting as an interface between different systems. This usually occurs between biological systems such as the human body and electronic systems, such as for example platforms for detecting signals.

Among the biomedical sensors, electrodes in particular detect signals relating to biological processes, such as the heart and cerebral activity, and convert them into electric signals.

A particularly interesting family of electrodes in the biomedical field is that of sensors for detecting electric phenomena coming from the human body, such as for example the electrocardiogram (ECG), the electroencephalogram (EEG), the electromiogram (EMG), which have an important role for therapeutic and diagnostic applications.

To date, the electrodes used are mainly made of tin, silver, sintered silver, Ag/AgCl combinations and gold. The electrodes may be divided into two large groups: standard electrodes, also called wet electrodes, and dry electrodes. The main difference between these two types of electrodes resides in the use or not of substances that allow an adequate passage of current between the conductive layers of the skin and the electrode, favoring the biosignal detection.

The electrodes may be further divided into two sub-groups, which are: single electrodes used for ECG, EEG, EMG, and integrated electrodes, typically in a cap, only used for EEG.

Single electrodes for EEG in the practice are small cylinders with a diameter of 5-10 mm, with the bottom base slightly concave, which are applied to the skin with thick and viscous pastes or electrolytic, conductive and adhesive gels. The application procedure of these electrodes provides for preparing the skin, through a slight non bloody abrasion, in order to eliminate non conductive cells of the outermost layer, called horny layer, and expand the capillaries in the derma, increasing the skin conductivity. After the cleaning and/or the use of conductive pastes or gels, the electrodes are applied to the skin and connected by insulated conductive wires to the instrumentation set up for recording the biosignals searched for.

In the case of integrated electrodes for EEG, a cap is used consisting of a fabric enclosure wherein the wires slide for connecting the electrodes outwards, and whereon holes are provided. A hollow plastic cylinder is fixed in each hole of the cap, which therefore remains in contact with the skin and/or the hair in the bottom part thereof. A pierced metal disc connected to an efferent conductor travelling into the cap interstice is applied and fixed on the crosswise median plane of each cylinder. After the cap application, the same skin is prepared at the cylinders, generally with greater difficulties than in the case of single electrodes due to the reduced dimensions of the skin access holes. To this end, chamfered needles are normally used for non bloody microabrasion. The conductive gel is then applied into each cylinder to be used, for connecting the electrode to the skin. If not already internally arranged, the external conductors are connected to each electrode used.

However, the above electrodes exhibit several drawbacks and usage limitations. It is necessary to consider that the electric features of the skin change according to the age, typically highly supplied and conductive in children and little supplied and poorly conductive in elderly people, and they also vary according to the amount of hair present.

A typical consequence of the configurations described above is to force the patient subject to EEG recording to reduced movements, if not to absolute immobility, or the EEG tracing may be unreliable.

Another drawback due to the use of the above electrodes is the presence of movement artifacts associated to capacitive couplings, that is, the recording of electric signals not originating by the analyzed system but due to the electrode friction on the skin caused by the patient's movements, although unintentional.

A great limitation imposed to the use of standard electrodes, or wet electrodes, is the impossibility of acquiring signals for long periods due to the partial or total evaporation of the conductive gel or paste used for increasing the electrode conductivity, with the consequent reduction or even the disappearance of the bioelectric signal.

However, the use of dry electrodes, which may eliminate the drawbacks caused by the presence of conductive gels or pastes exhibits other problems such as a high sensitivity of the sensors for the movement artifacts and high limitations of the overall dimensions of the support electronics, which is oversized and very expensive.

This greatly limits the possibilities of recording biopotentials in dynamic and normal action conditions of the patient in the surrounding environment, or of keeping the patient for extended sessions for monitoring the different biopotential activities.

Patent US6782283 and the U.S. patent application 2004/0054393 describe dry electrodes for detecting biological signals wherein there are needles or microneedles that penetrate the patient's horny layer for detecting the biopotentials.

However, these systems exhibit some limits in the use of the clinical practice as there is not a real applicator where the needles are inserted, required for detecting the signals, capable of keeping and adjusting the needle penetration depth according to the need, considering the intra- individual variability of skin thickness in the different areas of the body and inter- individual of the various subjects analyzed.

Another negative aspect of these systems is the lack of sterility of the needle matrix, in fact no systems for protecting the needle surface are described, which would then be exposed to external agents and would create local and systemic inflammatory reactions.

Patent application US2008/0114298 describes an applicator for microneedles provided with a flexible membrane that, through a mechanical manual pressure action, is capable of pushing the microneedle matrix into the skin.

However, the efficacy of this type of applicator, although simple and easy to use, is strictly related to the strength applied by the health operator for inserting the microneedles into the skin, considering that no fine adjustment mechanisms are provided for the insertion. The excessive strength applied on the applicator membrane may activate the mechanoreceptors sensitive to pressure present in the derma and consequently lead to the activation of a cascade of chemical signals, up to causing a sensation of pain.

US 6459918 describes a device equipped with an electrode capable of being inserted directly into a mice brain to measure electrical potential. The device has a wire electrode that in the terminal portion is directly inserted, through a hole in the skull, in the brain where measurements are to be taken.

This device has several drawbacks; in particular the electrode is not sufficiently rigid and is not designed to pierce the skin. Therefore a proper measurement of electric potential requires that a hole is previously made in the skull.

It would therefore be desirable to have electrodes consisting of needles for detecting biopotentials capable of detecting a potential difference in a steady fashion, without interferences or artifacts, capable of being applied without the aid of electrolytic gels or conductive pastes.

Moreover, it would be desirable to have electrodes for the detection of biopotentials that are easy to apply and adjust for detecting signals in different portions of the human body and capable of keeping a high sterility, so as to prevent possible infections caused by the application thereof.

It would be also desirable to have electrodes that are able to pierce the skin of the human body for a correct measure of the biopotential, without the use of external instruments.

The object of the present invention therefore is to provide a device for the application of electrodes consisting of needles for detecting biopotentials, capable of eliminating or reducing the above drawbacks. In particular, an object of the present invention is to provide a device for the application of electrodes consisting of needles which allows an easy application of said needles and prevents any movements thereof that may cause alterations in the signal detected.

Another object of the present invention is to provide a device for the application of electrodes consisting of needles which allows a fine adjustment of the needles so as to pierce the skin without causing pain while ensuring an adequate contact.

A further object of the present invention is to provide a device for the application of electrodes consisting of needles capable of ensuring high levels of sterility of the needles. According to the present invention, the above objects are achieved by a needle device for detecting bio signals through the skin of a mammal, comprising an array of needles fixed on a support, characterized in that said support is slidingly mounted within a container and is connected to actuating means suitable for moving said support from a non operating position wherein said array of needles is out of contact with the skin, to an operating position wherein said array of needles is in electric contact with the skin.

With the device according to the invention it is possible to obtain an electrode consisting of needles capable of being easily applied on the skin without movements of the same electrode, such as to generate artifacts. The device further allows adjusting the needle position so as to obtain a correct insertion into the skin and a high electric contact without pain for the patient. Moreover, with the device according to the invention it is possible to keep the needles forming the electrode sterile, so as to prevent infections caused by the application of the same needles.

Further features and advantages of the present invention will appear from the description of preferred but non exclusive embodiments of a device for the application of electrodes consisting of needles, shown by way of a non limiting example in the accompanying drawings, wherein:

Figure 1 shows a front view of the device during the operating step of insertion of the needles into the skin.

Figure 2 shows a partially cutaway view of a first embodiment of the device in the non operating step.

Figure 3 shows a partially cutaway view of a first embodiment of the device provided with electric contact, during the operating step of insertion of the needles into the skin.

Figure 4 shows a perspective exploded view of a first embodiment of the device according to the present invention. Figure 5 shows a perspective view of the electric contact and of a possible connection with external equipment according to a first embodiment.

Figure 6 shows a partially cutaway view of a second embodiment of the device in the non operating step.

Figure 7 shows a perspective exploded view of a second embodiment of the device according to the present invention.

Figure 8 shows a front view of the electric contact and of a possible connection with external equipment according to a second embodiment.

In order to better understand the limits generated by the use of standard electrodes for measuring biopotentials it is useful to describe the skin anatomy, with particular attention to the outermost layer that comes into direct contact with the electrodes.

The skin has organoleptic features that are considerably different in different areas of the body and structure variations caused by environmental conditions or individual factors.

The skin has a variable thickness comprised between 0.5 mm of the eyelids or of the prepuce, and 4 mm of the back of the neck. It has a significant resistance to deforming mechanical actions, whereto it can respond in a non linear elastic fashion; moreover, it adheres to the deep planes relative whereto it keeps a good mobility, facilitating the joint movements.

The skin represents an effective barrier of the body to infections, mechanical, thermal and chemical-physical insults of a various nature. From the anatomical point of view, it consists of three layers, differing by localization and structure; from the innermost layer towards the surface there are: hypodermis, derma and epidermis.

The hypodermis mainly consists of soft connective tissue, rich in elastic fibers and fatty tissue.

The derma consists of an essential amorphous substance wherein cells are immersed, among which fibroblasts, mastocytes, melanocytes and connective fibers; moreover, there are blood and lymphatic vessels and sensorial receptors, such as nociceptors and mechanoreceptors. The outermost layer, the epidermis, is the interface between skin and electrode. It is a keratinized stratified pavement epithelium, with a thickness comprised between 60 μιη and 150 μιη based on the body region and consists of a main cellular line: the keratinocytes. The various maturative stages of these cells characterize the continuous stratification of the epidermis.

Besides the keratinocytes there are the melanocytes, which synthesize melanin, the pigment useful for protecting fro UV radiations. Finally, there are the Langerhans cells, with an immune-competent meaning, and the Merkel cells. In the epidermis, starting from the derma towards the surface, there are four layers of keratmocytes: the basal layer, the spinous layer, the granular layer and the horny layer, consisting of nucleus-free comeocytes. From the chemical point of view, the first three layers, also called "vital epidermis", consist of 70% water, 15% proteins, 5% nucleic acids, and 5% lipids; whereas the horny layer contains 15% water, 70% proteins and 15% lipids.

The basal layer, located immediately in contact with the basal membrane, represents the germinative layer of the epidermis and is the only proliferating compartment of the epithelium. The basal cells form hemidesmosomes in the basal portion thereof and desmosomes with the adjacent keratinocytes.

In the spinous layer, the cells start synthesizing intermediate keratin filaments and have a typical appearance imparted by the cytoplasmatic extensions that form intercellular bridges between adjacent cells (spines).

More on the outside, the granular layer consists of keratinocytes containing abundant keratin filaments and visible basophile granulations (keratoialin granules).

On the surface there is the horny layer, consisting of flat cells in the shape of small flakes (horny lamellae) arranged parallel to the skin surface with a thickness ranging between ΙΟμιη and 15μιη. These cellular elements are free from nucleus and mainly contain keratin. The horny layer may be represented according to the "bricks and mortar" model, wherein the "bricks" are the compact comeocytes, arranged in about 15 rows of cells, consisting of a protein domain, whereas the "mortar" is represented by the intercellular lipid domain wherefrom the capability of storing the water present in the tissue also depends. Thanks to this particular composition, the homy layer is basically resistant to the water coming from the outside while it preserves the physiological moisturizing of the epidermis through natural moisturizing factors (NMF).

The physiological desquamation of the homy lamellae is supported by the movement and by the progressive maturing of the keratinocytes of the basal layer towards the surface. The tissue homeostasis of the epidermis is therefore maintained thanks to a delicate balance between the proliferation of the basal keratinocytes and deletion of the comeocytes in the homy layer.

This progressive maturing and migration of the keratinocytes from the basal layer into comeocytes is a complex process globally defined terminal differentiation, or keratinization, lasting about 30 days, characterized by deep morphological modifications in the nucleus and in the cytoplasm. From the electric point of view, for the anatomical reasons described above, the horny layer therefore is the primary source of a high impedance, thus influencing the biopotential measurements.

From the mechanical point of view, skin can be considered as a soft tissue, collagen - based, whose behavior can be classified as visco-elastic; however, considering rapid application of mechanical loads onto the skin, it can be considered as an elastic material (approximately with a Young's modulus of about 12 kPa, a Poisson ratio of 0.5 and with a failure stress of about 3 MP a). It means that skin could support large deformations before breaking occurs: as a consequence, only robust punches with an adequate aspect ratio (like needles) are able to pierce the skin, by exerting an high local pressure on it.

According to the present invention the needles or microneedles must be resistant to breakage or deformation by buckling when a stress greater than 3 MPa is applied onto the skin in order to pierce it and to detect a biosignal.

With reference to figures 1, 2, 3, 4, 5, a device for the application of electrodes consisting of needles, globally indicated with reference numeral 1 , shall be described hereinafter according to a first embodiment of the present invention.

Device 1 comprises a support 20 capable of seating a set of needles 60 which may have any shape or size, either solid or hollow, in particular according to this first embodiment the set of needles preferably is a set of microneedles.

The term needles according to the present invention refers to stretched thin and rigid tools ending with a tip, able to pierce the epidermis and in particular the horny layer, of the skin of a mammal to detect a difference in electrical potential.

The term microneedles according to the present invention refers to needles the dimensions whereof are less than one millimeter, in particular with a length of the protruding portion of the needle relative to the base whereon it is seated that is shorter than one millimeter. The needles or microneedles used may be of any material with suitable mechanical features and suitable electric conductivity. Preferably, the needles are of steel and may be packaged individually or in sets. The microneedles normally consist of a single piece, preferably of silicon.

Both needles and microneedles according to the present invention are able to pierce the skin only through the pressure applied on them, without the use of other instruments or devices that make holes before the insertion of needle or microneedle in the skin.

The set of needles 60 is coupled to a base 61, wherefrom they extend. Base 61 is in turn integrally coupled, by suitable coupling means, to support 20 so as to not allow the needles from separating from the support both in the application step and in the step of removal of the needles from the skin.

Base 61 of the set of needles 60 consists of a printed circuit element coated with a conductive material, in the case of silicon microneedles, base 61 consists of silicon itself since the microneedles are directly formed onto the same base.

In a further embodiment not described in the present description the needles, mainly steel needles, are incorporated in support 20 so as to obtain a solid and steady set of needles. In this case, base 61 is positioned in the top portion 21 of support 20 in order to ensure the electric contact between the needles and an electric connection means 50.

Support 20 may be coupled to a container 30 capable of seating said support 20 so that it may move therein switching from a first non operating position to a second operating position. Container 30 consists of a bottom wall 31 and of one or more side walls. If the device shape is circular, as shown in figure 4, the side wall 32 shall also be circular and shall delimit the circumference of the same device.

The bottom wall 31 and the side wall 32 of container 30 are jointed to one another and form a cavity 80 capable of seating support 20. Said cavity 80 is provided with sliding guides 35 fixed to the top portion of the side wall 32 and facing cavity 80 of container 30, that is, they are directed inwards of the cavity and oriented in the direction opposite that of the bottom wall 31. The guides are flexible blades arranged at grooves 36 of the side wall 32 of container 30.

According to a preferred but non limiting embodiment represented in figure 4, said cavity 80 is a cylindrical cavity. Said support 20 is a disc provided with grooves 22 that can be coupled to relative guides 35 of container 30. The contact between support 20 and the inside wall of container 30, which occurs through the contact of grooves 22 of support 20 with guides 35 of container 30, allows support 20 to keep the non operating position, preventing support 20 from coming out of cavity 80 by the gravitational effect. The position is kept thanks to the elastic pressure force exerted by guides 35.

The term "non operating position", according to the present invention, indicates the position of support 20 relative to container 30, such that the needles are confined within the container, thus preventing any contact between needles 60 and skin 15 whereon the device is rested. The term "operating position", according to the present invention, indicates the position of support 20 relative to container 30, such that the needles protrude from the bottom profile of container 30 so that when the device is positioned on the patient's skin, the needles pierce the outermost layer of the skin ensuring an adequate electric contact. The passage of support 20, and thus of needles 60, from the non operating position to the operating position occurs thanks to the sliding of support 20 along guides 35 of container 30. Such sliding occurs thanks to the thrust exerted by suitable actuating means 40 coupled to support 20, which apply a stronger force to the support than the elastic pressure force generated by guides 35.

The actuating means 40 exert the necessary force on the needles 60 in order to obtain stresses greater than 3 MPa onto the skin to pierce it, for the correct detection of biosignals.

Said actuating means 40 may be a mechanism of the screw/nut screw type, wherein screw 41 imparts the movement to support 20 thanks to the contact of end 42 with the top portion 21 of support 20. Said contact is free, that is, does not form an integral connection between the screw and the support, so as to prevent the rotation of support 20 with consequent impossibility of application of the needles. The optional rotation imparted to support 20 and generated by the friction force due to the contact between container and screw is prevented by the coupling of guides 35 of container 30 with grooves 22 of support 20. The rotational motion of screw 41 is thus transformed into a translational motion of support 20.

The top end 43 of said actuating means 40 protrudes from the bottom wall 31 of container 30 so as to allow actuating screw 41 rotating portion 43 and obtaining the sliding of support 20. Nut screw 33, that is, the threaded hole suitable for receiving screw 41 of the actuating means 40, is obtained in the bottom wall 31 of container 30 and ensures a solid coupling between the actuating means 40 and container 30 of the application device.

Thanks to the actuating means 40 it is possible to obtain a fine adjustment of support 20 and of needles 60, so as to obtain an optimal penetration into the epidermis at the desired depth. The electric connection between the matrix of needles 60 and the external devices and circuits required for making the measurement, such as for example the electrocardiograph, occurs through an electric connection means 50 arranged on the bottom wall 31 of container 30. The electric connection means 50 is provided with a threaded portion 51 that may be coupled to the threaded hole 34 obtained on the bottom wall 31 of container 30. The electric connection means 50, integral with container 30 through the threaded coupling 51-34, is in permanent contact with support 20 and with needles 60 so as to ensure the electric connection with the external equipment.

The electric connection means 50 exhibits an elastic linkage 52 arranged within cavity 80 of container 30. Said elastic linkage 52 allows a permanent contact between the array of needles and the same connection means, such as to ensure the electric contact between the skin and the external equipment. The electric connection means 50 also exhibits a portion 53 that protrudes from the bottom wall 31 of container 30. Portion 53 may be coupled to a connector 90 of the external equipment so as to obtain the electric connection.

The elastic linkage 52 of the electric connection means 50 consists of a spring capable of extending by an extent corresponding to the entire sliding of support 20 relative to container 30. Said spring ensures the electric continuity between the needles and the same connection means.

In order to ensure the required sterility of the needles and thus prevent possible infections caused by the contact of non sterile needles with the skin, the device for applying the electrodes is provided with a protective membrane 70 positioned in the bottom portion of container 30. Said protective membrane 70 keeps cavity 80, and consequently needles 60, insulated from the external environment when the needles are in non operating position.

The protective membrane 70 is removably fixed to the bottom edge 37 of the side wall 32 of container 30 and can easily be removed, for example by tearing, before using the equipment, allowing the needles to contact the skin.

With reference to figures 6, 7 and 8, relating to a second embodiment of the present invention, the device for the application of electrodes consisting of needles, globally indicated with reference numeral 2, comprises a container 130 having a bottom wall 131 and one or more side walls 132. If the device shape is circular, as shown in figure 7, the side wall 132 shall also be circular and shall delimit the circumference of the same device.

The bottom wall 131 and the side wall 132 of container 130 are jointed to one another and form a cavity 80. Cavity 180 is provided with sliding guides 135 consisting of flexible blades arranged at grooves 136 of the side wall 132 of container 130. Guides 35 are fixed to the top portion of the side wall 132 and facing cavity 180 of container 130, that is, they are directed inwards of the cavity and oriented in the direction opposite that of said bottom wall 131.

According to a preferred but non limiting embodiment represented in figure 7, said cavity 180 is a cylindrical cavity.

A support 180 is seated within cavity 180 so that it may slidingly move therein switching from a first non operating position to a second operating position. Said support 120 is a disc provided with grooves 122 that can be coupled to relative guides 135 of container 130.

The set of needles 160 extends from a base 160 which is integrally coupled, by suitable coupling means, to support 120 so as to not allow the needles from separating from the support both in the application step and in the step of removal of the needles from the skin. In this second embodiment, the needles preferably are steel needles mounted on a base 161. Base 161 consists of a printed circuit element coated with a conductive material such as to ensure the electric contact between the needles and the electric connection means 150.

The side walls 132 are provided with a travel end rib 100, arranged in the proximity of the end portion of the side wall, which extends inwards of said cavity 180. Said travel end 100 prevents support 120 from coming out of cavity 180 of container 130 when the device is removed from the skin. Support 120 has a larger size than the opening of cavity 180 defined by rib 100 and opposite the bottom wall 131.

Rib 100 also provides to the adjustment of the projection of needles 160 since the contact of support 120 with rib 100 prevents an excessive projection of needles 160 from container 130. The thickness of rib 100 is determined according to the needle length, so as to ensure an optimal projection of the same. The use of larger needles is compensated with a larger thickness of rib 100.

The passage of support 120, and thus of needles 160, from the non operating position to the operating position occurs thanks to the sliding of support 120 within cavity 180. Such sliding occurs thanks to the thrust exerted by suitable actuating means 140 coupled to support 120. The actuating means 140 comprise a screw 141, integral with the top portion 121 of support lq20. Screw 141 crosses a hole 133 obtained in the bottom wall 131 of container 130 and protrudes from the same container. Screw 141 is coupled to a threaded ring nut 45 arranged on the outside of container 131. The rotation of the threaded ring nut 45 imparts the movement to screw 141 and causes the shifting of support 120.

The rotation of support 120, which may occur due to the rotation of screw 141 coupled to the same support, is prevented by the coupling of guides 135 with grooves 122 of support 120. The electric connection between needles 160 and the external devices and circuits required for detecting the biosignals occurs through an electric connection means 150 arranged in permanent contact with needles 160. The electric connection means 150 consists of a conductor 155 coupled to support 120. Conductor 155, through a first portion 152, ensures a permanent contact between needles 160 and the external devices, as it is stiffly connected to base 161 of needles 160.

Conductor 155 is provided with a portion 153 capable of operatively connecting to a connector 190 of the external equipment so as to ensure the electric contact.

The electric connection means 150 protrudes from container 130 through a hole 134 obtained in the bottom wall 131 of the same container. Hole 134 has a larger size than the electric contact 150, so that the same contact may freely move through hole 134. During the passage of needles 160 from the non operating step to the operating step, crossing hole 134 contact 150 keeps the electric contact between the array of needles 160 and the external equipment. As described in relation to the first embodiment, also in the embodiment of figures 6 and 7, the device may be provided with a protective membrane, not shown, positioned in the bottom portion of container 130, having the function of insulating the needles or the microneedles from the external environment in the non operating position.

Claims

1. A needle device (1; 2) for detecting biosignals through the skin of a mammal, comprising an array of needles (60; 160) that extend from a base (61; 161) coupled to a support (20; 120), characterized in that said support (20; 120) is slidingly mounted within a container (30; 130) and is connected to actuating means (40; 140) suitable for moving said support from a non operating position wherein said array of needles (60; 160) is out of contact with the skin (15), to an operating position wherein said array of needles (60; 160) is in electric contact with the skin (15), said needles (60) being able to pierce the skin in order to obtain said detecting of biosignals.

2. Device (1; 2) according to claim 1, characterized in that said needles are microneedles.

3. Device (1; 2) according to claim 1, characterized in that said container (30; 130) is provided with a cavity (80; 180) delimited by a bottom wall (31; 131) and by one or more side walls (32; 132), said actuating means (40; 140) being associated to said bottom wall (31; 131).

4. Device (1; 2) according to claim 3, characterized in that said cavity (80; 180) is provided with sliding guides (35; 135) protruding inwards of the cavity (80; 180); said guides (35; 135) consisting of flexible blades fixed to the top portion of the side wall (32; 132) and oriented inwards of the cavity (80; 180) in the direction opposite said bottom wall (31; 131) of the container (30; 130).

5. Device (1; 2) according to claim 3, characterized in that said cavity (80; 180) is a cylindrical cavity and said support (20; 120) is a disc provided with grooves (22; 122) suitable for receiving said sliding guides (35; 135).

6. Device (2) according to claim 3, characterized in that said container (130) is provided with a travel end rib (100) for said support (120), said rib extending inwards of said cavity (180), such that the exit of said support (120) from said cavity (180) is prevented.

7. Device (1) according to claim 1, characterized in that said actuating means (40) comprises a screw (41) coupled to a threaded hole (33) obtained in said bottom wall (31) of the container (30).

8. Device (2) according to claim 1, characterized in that said actuating means (140) comprises a screw (141) coupled to said support (120) and crossing a hole (133) obtained in said bottom wall (131) of said container (130); said screw (141) being coupled to a threaded ring nut (45) arranged on the outside of said container (130).

9. Device (1; 2) according to claim 1 or 2, characterized in that it comprises electric connection means (50; 150) between the base (61; 161) wherefrom the needles (60; 160) extend and an external equipment.

10. Device (1) according to claim 9, characterized in that said needles are microneedles and said electric connection means (50) are provided with an elastic linkage (52) which keeps the array of microneedles (60) in contact with said electric connection means (50) during the movement of said array of microneedles (60) from the operating position to the non operating position.

11. Device (1) according to claim 10, characterized in that said electric connection means (50) are provided with a threaded portion (51) that may be coupled to a threaded hole (34) obtained on the bottom wall (31) of the container (30).

12. Device (2) according to claim 9, characterized in that said electric connection means (150) comprises a conductor (155) crossing a hole (134) obtained in the bottom wall (131) of said container (130), and stiffly connected to said base (161) wherefrom the needles (160) extend.

13. Device (1) according to claim 1, characterized in that it comprises a protective membrane (70) removably fixed to the bottom edge (37) of the side wall (32) of the container (30).

14. Device (1) according to claim 1, characterized in that said mammal is a human.

15. Device (1) according to claim 1, characterized in that said needles (60) are resistant to breakage or deformation by buckling when a stress greater than 3 MPa is applied onto the skin, in order to pierce said skin and detect said biosignals.