DUAL BEAM LASER TRANSFER

Abstract

Methods and devices for transferring biological or non-biological material coated on a front surface of a donor substrate to a front surface of a receiver substrate. An example of implementation: the front surface of the donor substrate is facing the front surface of the receiver substrate. The donor surface comprises a transparent portion and an absorbing layer on a front side of the transparent portion. A first laser beam of a laser irradiates a portion of a back side of the transparent portion to increase the pressure and/or temperature of the absorbing layer to eject a portion of the biological or non-biological material from the donor substrate and transfer the portion of the material to the receiver surface. The portion of the material transferred on the second substrate is post-processed by irradiating with a second laser beam of a laser a portion of the front side of the receiver surface.

Claims

1. A method of transferring a biological or non-biological material coated on a front surface of donor substrate to a front surface of a receiver substrate, the front surface of the donor substrate facing the front surface of the receiver substrate, the donor substrate comprising a transparent portion and an absorbing layer on a front side of the transparent portion, the method comprising: irradiating with a first laser beam of a laser a portion of a back side of the transparent portion to increase the pressure and/or temperature of the absorbing layer to eject a portion of the biological or non-biological material from the donor substrate and transfer the portion of the biological or non-biological material to the receiver surface; post-processing the portion of the biological or non-biological material transferred on the receiver substrate by irradiating with a second laser beam of a laser a portion of the front side of the receiver surface.

2. The method according to claim 1, further comprising: removing the donor substrate after the portion of the biological or non-biological material has been transferred.

3. The method according to claim 1, further comprising setting a fluence of the first laser beam at between 50 and 1500 mJ/cm.sup.2.

4. The method according to claim 1, further comprising setting a fluence of the second laser beam at between 30 and 500 mJ/cm.sup.2.

5. The method according to claim 1, further comprising selecting a wavelength of the first and second laser beams at between 100 nm and 1550 nm.

6. The method according to claim 1, further comprising focusing the first laser beam on the donor surface to select the portion of the biological or non-biological material to eject from the donor substrate.

7. The method according to claim 1, wherein transferring comprises repeating the irradiating of the first substrate to generate a pattern of biological or non-biological material on the receiver substrate.

8. The method according to claim 1, wherein transferring comprises liquid phase transferring by focusing the first laser beam to cause formation of an elongated liquid jet travelling towards the receiver substrate.

9. The method according to claim 1, wherein transferring comprises solid phase transferring by focusing the first laser beam to cause formation of a solid flyer travelling towards the receiver substrate.

10. The method according to claim 1, comprising transferring non-biological material, wherein post-processing comprises photo-polymerization of the transferred non-biological material.

11. The method according to claim 1, comprising transferring biological material, wherein post-processing comprises functionalizing the transferred biological material.

12. The method according to claim 11, wherein functionalizing comprises irradiating the portion of the biological material on the receiver surface to cause binding of the portion of the biological material on a selected part of the receiver substrate.

13. The method according to claim 12, wherein binding comprises inducing a covalent bond between a first element of the biological material and a second element of the receiver substrate.

14. The method according to claim 13, comprising inducing a covalent bond between a sulfur element of the biological material and a carbon element of the receiver substrate.

15. The method according to claim 13, comprising inducing a covalent bond between a nitrogen element of the biological material and a carbon element of the receiver substrate.

16. The method according to claim 1, comprising transferring a pharmaceutical material to the receiver substrate, wherein post-processing comprises adding a second layer of biodegradable material to encapsulate said transferred pharmaceutical material.

17. The method according to claim 1, further comprising adjusting the density of the laser using a rotating waveplate and a polarizer.

18. An irradiation configuration comprising: a donor substrate, having a transparent portion and an absorbing layer on a front surface of the transparent portion coated with a biological or non-biological material; a receiver substrate, having a front surface facing the front surface of the donor substrate; a pulsed laser source, configured to irradiate with a first laser beam a back side of the donor substrate during a transferring mode of operation and to irradiate a front side of the receiver substrate during a post-processing mode of operation.

19. The irradiation configuration according to claim 18, further comprising a first stage to hold the donor substrate and a second stage to hold the receiver substrate, wherein the stages are independently and relatively moveable with respect to the laser source.

20. The irradiation configuration according to claim 19, further comprising a computer controller to control the stages and the pulsed laser source to synchronize the pulsed laser source with the stages.

21. The irradiation configuration according to claim 20, further comprising a focus element to focus the first and second laser beams on the donor and receiver substrates, respectively.

22. The irradiation configuration according to claim 21, further comprising a mirror to guide the first and second beams to the focus element.

23. The irradiation configuration according to claim 22, further comprising an image capturing apparatus, to monitor irradiation, transferring and post-processing.

24. The irradiation configuration according to claim 22, wherein the image capturing apparatus is a CCD camera.

25. The irradiation configuration according to claim 23, wherein the focus element is a microscope objective and the image capturing apparatus is placed behind the mirror to monitor irradiation, transferring and post-processing using the inverted microscope principle.

26. A computer program product comprising program instructions for causing a computing system to perform a method according to claim 1.

27. A computer program product according to claim 26, embodied on a storage medium.

28. A computer program product according to claim 26, carried on a carrier signal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Non-limiting examples of the present disclosure will be described in the following, with reference to the appended drawings, in which:

[0028] FIG. 1 schematically illustrates a dual beam transfer configuration, according to an example;

[0029] FIG. 2 schematically illustrates a method of transferring a biological or non-biological material, according to an example.

DETAILED DESCRIPTION OF EXAMPLES

[0030] FIG. 1 schematically illustrates a dual beam transfer configuration, according to an example. During a transfer mode of operation (a) a donor substrate 105 is coated on a front surface FD with a biological or non-biological material 110. The front surface FD of the donor substrate 105 is placed facing the front surface FR of the receiver substrate 115. The donor substrate 105 comprises a transparent portion 105a and an absorbing layer 105b on a front side of the transparent portion. A laser source 120 produces a first laser beam B1 that is reflected by mirror 125 and then focused by focusing element 130. The first laser beam B1 of laser source 120 irradiates a portion of a back side BD of the transparent portion to increase the pressure and/or temperature of the absorbing layer to eject a portion 110a of the biological or non-biological material from the donor substrate 105 and to transfer the portion 110a of the biological or non-biological material to the receiver substrate 115.

[0031] During a post-processing mode of operation (b) the donor substrate 105 is removed and the portion 110a of the biological or non-biological material transferred on the second substrate 115 is processed by irradiating with a second laser beam B2 of the laser.

[0032] FIG. 2 schematically illustrates a method of transferring a biological or non-biological material, according to an example. In block 205, a front side of a donor substrate is coated with biological or non-biological material. In block 210, a front side of a receiver substrate is placed opposite to a front side of the donor substrate. In block 215, a transparent back side of the donor substrate is irradiated with a first laser beam from a laser source until a portion of the biological or non-biological material is transferred to the receiver surface. In block 220, the donor substrate is removed and then, in block 225, the transferred biological or non-biological material on the front side of the receiver surface is post-processed by irradiating with a second laser beam of the laser source. The characteristics of the second laser beam may be different from the characteristics of the first laser beam.

[0033] One example of the present invention relates to the transfer of a monomer on a glass substrate using the first laser beam of the dual beam laser setup and the photo-polymerization of the transferred monomer with the second laser beam.

[0034] The donor substrate has been prepared by dissolving acrylic acid (CH2CHCOOH) in water, where 20 l of the solution have been applied on a circular quartz substrate (donor substrate, 25.4 mm diameter, 1 mm thickness) using the blade-coating technique to produce a uniform thin liquid film.

[0035] The apparatus employed is the dual beam laser transfer setup where for the transfer a pulsed Nd:YAG laser source operating at 355 nm was used with a pulse duration of 8 ns. This laser wavelength was selected since a thin Ti coating was applied on the circular quartz substrate as an absorbing layer to absorb the laser energy and induce the propulsion of the material towards the receiver substrate. The laser beam was focused using a microscope objective (15 magnification) on the donor substrate and the laser spot size could be varied between 1-300 m. The system operated at mask projection conditions and the process could be viewed in real time using a high power imaging system based on the inverted microscope principle with the aid of a CCD camera. The energy density of the laser may be adjusted using a rotating waveplate and a polarizer between 50-250 mJ/cm.sup.2.

[0036] The monomer in solution-coated donor substrate was placed in close proximity to the receiving glass substrate, with the coated side facing the glass substrate. The laser beam was projected onto the donor substrate and the laser fluence was set at 80 mJ/cm.sup.2, while the laser spot shape was rectangular with a diameter of 5 m. The transfer process resulted in the deposition of rectangular acrylic acid in water pixels of approximately 5 m diameter and 20 nm thickness on selected areas of the glass substrate and the process was performed multiple times to produce an array of 1010 pixels using a single laser pulse for each spot. In this example of the present invention, the donor and the receiver substrates were placed on micrometer-precision computer-controlled stages and were synchronized with the laser source.

[0037] For the photopolymerization of the transferred material the donor substrate was removed and a single laser pulse was used to irradiate each transferred pixel. The laser source employed for the photopolymerization was a pulsed Nd:YAG laser source operating at 355 nm with a pulse duration of 8 ns. The laser spot on the glass substrate was adjusted at 10 m and each pulse irradiated the entire surface of each previously transferred pixel. The laser fluence was adjusted at 130 mJ/cm.sup.2 and each pixel received one laser pulse. The process was monitored using the high power imaging system described above.

[0038] Another example of the present invention includes the transfer and functionalization of unmodified DNA on specific areas of an epoxy modified glass substrate. The produced substrate is used to develop DNA assays for patient stratification.

[0039] The donor substrate has been prepared by dissolving unmodified DNA in phosphate buffer (pH 7.3) to produce a 10 M solution, where 6 l of the solution have been applied on a circular quartz substrate (donor substrate, 25.4 mm diameter, 1 mm thickness) using the blade-coating technique to produce a uniform thin film.

[0040] The apparatus employed for the transfer and the functionalization of the substrate included a pulsed Nd:YAG laser source operating at 355 nm with a pulse duration of 8 ns. This laser wavelength was selected since a thin Ti coating was applied on the circular quartz substrate as an absorbing layer to absorb the laser energy and induce the propulsion of the biomaterial towards the receiver substrate. The laser beam was focused using a microscope objective (15 magnification) on the donor substrate and the laser spot size could be varied between 1-300 m. The system operated at mask projection conditions and the process could be viewed in real time using a high power imaging system based on the inverted microscope principle with the aid of a CCD camera. The energy density of the laser may be adjusted using a rotating waveplate and a polarizer between 50-500 mJ/cm.sup.2.

[0041] The unmodified DNA-coated quartz substrate (donor substrate) was placed in close proximity to the receiving epoxy modified glass substrate, with the coated side facing the glass substrate. The laser beam was projected onto the donor substrate and the laser fluence was set at 250 mJ/cm.sup.2, while the laser spot shape was circular with a diameter of 5 m. The transfer process resulted in the deposition of circular DNA spots of approximately 10 m diameter and 20 nm thickness on selected areas of the glass substrate and the process was performed multiple times to produce an array of 100100 DNA spots using a single laser pulse for each spot. In this example of the present invention, the donor and the receiver substrates were placed on micrometer-precision computer-controlled stages and were synchronized with the laser source.

[0042] For the functionalization of the laser transferred unmodified DNA on the epoxy modified glass substrate, the donor substrate (circular quartz) was removed and a single laser pulse was employed for each DNA spot. The laser source employed for the functionalization was a pulsed Nd:YAG laser source operating at 355 nm with a pulse duration of 8 ns. The laser spot on the receiver substrate was adjusted at 15 m and each pulse irradiated the entire surface of each DNA spot. The laser fluence was adjusted at 50 mJ/cm.sup.2 and each DNA spot received one laser pulse. The process was repeated multiple times to functionalize selected areas of the glass substrate, where the biological material has been previously transferred onto. The process was monitored using the high power imaging system described above.

[0043] Another example of the present invention includes the transfer of Cy5-conjugated donkey anti-rabbit (DAR-Cy5) antibodies on specific areas of a silicon nitride (Si.sub.3N.sub.4) substrate. The produced substrate is used to develop enzyme-linked immunosorbent assay (ELISA) assays.

[0044] The donor substrate has been prepared by dissolving a stock antibody solution (5 mg/ml) in phosphate buffer saline (pH 7.0) and performing a 1:50 dilution to produce a 0.1 mg/ml solution, were 10 l of the solution have been drop casted on a circular quartz substrate (donor substrate, 25.4 mm diameter, 1 mm thickness) and left to dry overnight to produce a uniform thin film (solid-phase transfer).

[0045] The apparatus employed for the transfer included a pulsed Nd:YAG laser source operating at 355 nm with a pulse duration of 8 ns. This laser wavelength was selected since a thin Ti coating was applied on the circular quartz substrate as an absorbing layer to absorb the laser energy and induce the propulsion of the biomaterial towards the receiver substrate. The laser beam was focused using a plano-convex lens (50 mm focal length) on the donor substrate and the laser spot size could be varied between 1-300 m. The system operated at mask projection conditions and the process could be viewed in real time using a high power imaging system based on the inverted microscope principle with the aid of a CCD camera. The energy density of the laser may be adjusted using a rotating waveplate and a polarizer between 100-400 mJ/cm.sup.2.

[0046] The antibody-coated quartz substrate (donor substrate) was placed in close proximity (10-3000 m) to the receiving silicon nitride substrate, with the coated side facing the silicon nitride substrate. The laser beam was projected onto the donor substrate and the laser fluence was set at 200 mJ/cm.sup.2, while the laser spot shape was rectangular with a diameter of 30 m. The transfer process resulted in the deposition of rectangular antibody spots of 30 m diameter on selected areas of the silicon nitride substrate and the process was performed multiple times to produce an array of 100100 antibody spots using a single laser pulse for each spot. In this example of the present invention, the donor and the receiver substrates were placed on micrometer-precision computer-controlled stages and were synchronized with the laser source.

[0047] For the functionalization of the laser transferred antibodies on the silicon nitride substrate, the donor substrate (circular quartz) was removed and a single laser pulse was employed for each antibody spot. The laser source employed for the functionalization was a pulsed Nd:YAG laser source operating at 355 nm with a pulse duration of 8 ns. The laser spot on the receiver substrate was adjusted at 30 m and each pulse irradiated the entire surface of each antibody spot. The laser fluence was adjusted at 30 mJ/cm.sup.2 and each antibody spot received one laser pulse. The process was repeated multiple times to functionalize selected areas of the silicon nitride substrate, where the biological material has been previously transferred onto. The process was monitored using the high power imaging system described above.

[0048] Another example of the present invention relates to the laser transfer of active pharmaceutical ingredients, in this case paracetamol (other ingredients may be theophylline, felodipine and hydrochlorothiazide etc) and the subsequent laser encapsulation (functionalization) with a biodegradable polymer (polycaprolactone, PCL, etc) on a substrate suitable for drug delivery applications for example on a biodegradable material.

[0049] The donor substrate has been prepared by dissolving a small quantity of paracetamol (10 mg, paracetamol) in water and drop casting 10 l of the solution on a circular quartz substrate (donor substrate, 25.4 mm diameter, 1 mm thickness) to produce a uniform thin film.

[0050] The apparatus employed for the transfer of paracetamol on the receiver substrate included a pulsed Nd:YAG laser source operating at 532 nm with a pulse duration of 8 ns. This laser wavelength was selected since a thin Au coating was applied on the circular quartz substrate as an absorbing layer to absorb the laser energy and induce the propulsion of the material towards the receiver substrate. The laser beam was focused using a microscope objective (15 magnification) on the donor substrate and the laser spot size could be varied between 1-300 m. The system operated at mask projection conditions and the process could be viewed in real time using a high power imaging system based on the inverted microscope principle with the aid of a CCD camera. The energy density of the laser may be adjusted using a rotating waveplate and a polarizer between 50-200 mJ/cm.sup.2. After the transfer of paracetamol on selected areas of the receiver substrate the donor substrate is removed and a second laser beam is used to transfer PCL using the 355 nm (8 ns pulse duration) wavelength on the areas where paracetamol was previously transferred to post process the transferred material on the receiver substrate in order to form the encapsulation matrix.

[0051] The laser spot on the receiver substrate can be varied between 1-300 m and each pulse irradiates the entire surface of each paracetamol spot. The laser fluence may be varied between 30-150 mJ/cm.sup.2 and each paracetamol spot received one laser pulse. The process was repeated multiple times to encapsulate selected areas on the receiver substrate, where the paracetamol has been previously transferred onto. The process was monitored using the high power imaging system described above.

[0052] The proposed method can be used in the following applications: [0053] Polymer, powder and inorganic material arrays and patterns/structures (lines, pads) that may be used as functional materials in microelectronic applications (transistors, sensors), scaffolds (3D building blocks of biomaterial hosting and proliferation), micro-components and opto-electronic applications. [0054] Chemical substances used in pharmaceutical drugs (Paracetamol C8H9NO2, etc.). [0055] Biomaterial microarrays, protein and antibody assays, etc. with a functionalized pattern diameter down to 1 m, and hence it can be used to selectively functionalize a large number of different biomaterial microarrays (i.e. up to 1000 different DNA arrays) on the same substrate for i.e. DNA analysis, ELISA tests, patient stratification etc. Moreover, in DNA analysis, since washing and blocking processes are often required it would be useful to apply the same liquids on the same substrate avoiding excessive use of washing and blocking reagents that in biomedical sciences are far too expensive. This also leads to a reduction of the processing time, hence more samples can be analyzed in a shorter time window.

[0056] Although only a number of examples have been disclosed herein, other alternatives, modifications, uses and/or equivalents thereof are possible. Furthermore, all possible combinations of the described examples are also covered. Thus, the scope of the present disclosure should not be limited by particular examples, but should be determined only by a fair reading of the claims that follow. If reference signs related to drawings are placed in parentheses in a claim, they are solely for attempting to increase the intelligibility of the claim, and shall not be construed as limiting the scope of the claim.

[0057] Further, although the examples described with reference to the drawings comprise computing apparatus/systems and processes performed in computing apparatus/systems, the invention also extends to computer programs, particularly computer programs on or in a carrier, adapted for putting the system into practice.