Elsevier

Applied Surface Science

Volume 278, 1 August 2013, Pages 250-254
Applied Surface Science

Biosensors by means of the laser induced forward transfer technique

https://doi.org/10.1016/j.apsusc.2012.11.064Get rights and content

Abstract

This work presents the direct laser printing of thiol-modified oligonucleotides onto the surface of 3-glycidoxypropyltrimethoxysilane (GOPTS)-functionalized ultra-thin Low temperature oxide (LTO)/Si membranes for the fabrication of a label-free capacitive biosensor. During the hybridization of the target oligonucleotides with their immobilized complementary strands, various interaction forces develop, which contribute toward the deflection of the ultrathin LTO membranes, resulting in a capacitance shift. A number of different parameters were investigated for the laser printing conditions of the oligonucleotides that in turn affect the maximum deflection of the membranes and therefore the capacitance variation.

Highlights

► This method resulted in the deposition of biomaterials without loss of their bioactivity. ► This method allowed the percentage coverage of the sensors’ membranes. ► This method allowed the laser printing of three types of oligonucleotides with no risk of mixing the biomaterials. ► The hybridization of the fully complementary probes to the target analyte in solution was detected with capacitance measurements.

Introduction

Laser induced forward transfer (LIFT) is a direct write technique that allows the deposition of liquid and solid materials with high spatial resolution. The LIFT technique was first employed by Bohandy et al. [1] for the deposition of metals and since then, has been used for the printing of many different types of materials such as superconductors [2] and polymers [3], but most importantly for the printing of biomolecules such as cells [4], proteins [5] and DNA [6].

The technique relies on the displacement of the material to be deposited from a donor substrate to a receiver substrate. The donor substrate in most liquid phase LIFT experiments consists of three layers [7], [8]. The first layer must not demonstrate spectral absorption to the laser beam (quartz), the second layer is an absorbing titanium layer (Ti) and the third layer corresponds to the material to be transferred. Irradiation of the donor substrate results in the rapid heating of the metal film and the explosive boiling of the adjacent liquid, thus producing a high vapor cavity, which expands and drives through the remaining film [9]. The receiving substrate is placed parallel to the donor substrate, so that, following irradiation, the biomaterial is printed onto the former.

The LIFT technique has significant advantages over several other deposition techniques such as spotting [10], inkjet [11] and photolithography [12] since it is a contactless direct write technique, which does not require the use of masks or nozzles. Both LIFT and droplet-on-demand inkjet printing techniques have the ability to deposit micrometer-sized droplets of ink into user-defined patterns. However, since LIFT technique is nozzle less, it can handle a wider range of ink properties and does not suffer from clogging and material compatibility issues associated with the more prevalent nozzle-based techniques [13].

In this paper we present the direct laser printing of three different oligonucleotide probe sequences onto the surface of capacitive sensors’ membranes [14]. The capacitive sensor consists of 60 ultra-thin circular LTO/Si membranes onto which the oligonucleotide probe solutions are deposited for the fabrication of the biosensor and 4 aluminum (Al) sensors which are used as a reference for the electronic readout circuit.

The first oligonucleotide was fully complementary to the target analyte in solution, while the second probe formed one internal base pair mismatch with the same target sequence. The third oligonucleotide was non-complementary to the target sequence and was used as a reference sequence to quantify non-specific binding (Fig. 1). The interaction of the DNA probes with their targets can be detected by the stress that develops across the surface of the capacitive membranes. As it has already been reported [15], [16], a number of forces contribute toward the phenomena observed across the surfaces of the membranes such as electrostatic repulsions and steric hindrance between the DNA strands, all of which, however, can be shielded off effectively with the use of a buffer of high ionic strength. Recently published work suggests that the major contributing factor toward the surface stress recorded upon DNA immoblization and hybridization is due to hydration forces [17]. As it has been previously shown by our research group, maximizing probe grafting density enhances the hydration forces that develop following target recognition by the deposited oligonucleotides [18]. Detection of single base pair mismatches is achieved by the different surface stress that develops from that recorded when fully complementary strands hybridize. As far as the non-complementary probes are concerned, the surface stress that develops due to non-specific binding is negligible.

Section snippets

Materials

All reagents were obtained from Aldrich Chemical. All solutions were made with deionized water (18  cm resistivity) from a Millipore MilliQ system. DNA oligonucleotides were purchased from Eurofins MWG Operon (Ebersberg, Germany). The 15 nucleotide bases-long probe oligomers contained a 5′-thiol C5 linker and were labeled with FAM (6-carboxyfluorescein) at their 3′ end. The sequences of the complementary, the one base pair mismatch and the non-complementary to the target analyte probes were

Laser printing process

Prior to the deposition of the oligonucleotides’ solution onto the surface of the capacitive sensor membranes, the initial experimental set-ups were carried out onto planar GOPTS-functionalized LTO/Si surfaces in order to establish the size and morphology of the deposited droplets and get an estimate of the percentage coverage of the membranes that will be achieved with different laser printing conditions. As shown in Fig. 3, there is a relationship between the droplet size and the energy

Conclusions

In this work, we presented a capacitive biosensor for the detection of the DNA hybridization process. For the fabrication of the biosensor, oligonucleotide probes have been laser printed onto ultra-thin LTO/Si membranes which are the sensing elements. Laser printing (LIFT) ensured the deposition of the oligonucleotides with high spatial resolution, enabling the use of the sensor for multi-analyte detection. To test the bio-reactivity of the printed biomolecules we used a confocal fluorescent

Acknowledgements

The research activities that led to these results, were co-financed by Hellenic Funds and by the European Regional Development Fund (ERDF) under the Hellenic National Strategic Reference Framework (ESPA) 2007–2013, according to Contract no. MICRO2-50 and Contract no. MICRO2-45.

This research has been co-financed by the European Union (European Social Fund–ESF) and Greek national funds through the Operational Program “Education and Lifelong Learning” of the National Strategic Reference Framework

References (22)

  • V. Tsouti et al.

    A chemical sensor microarray realized by laser printing of polymers

    Sensors and Actuators B

    (2010)
  • V. Tsouti et al.

    Detection of DNA mutations using a capacitive micro-membrane array

    Biosensors and Bioelectronics

    (2010)
  • V. Tsouti et al.

    Self-aligned process for the development of surface stress capacitive biosensor arrays

    Sensors & Actuators, B

    (2012)
  • J. Bohandy et al.

    Metal deposition from a supported metal film using an excimer laser

    Journal of Applied Physics

    (1986)
  • E. Fogarassy et al.

    Laser-induced forward transfer of high-Tc YBaCuO and BiSrCaCuO superconducting thin films

    Journal of Applied Physics

    (1989)
  • J.A. Barron et al.

    Laser printing of single cells: statistical analysis, cell viability, and stress

    Annals of Biomedical Engineering

    (2005)
  • C. Boutopoulos et al.

    Direct laser printing of biotin microarrays on low temperature oxide on Si substrates

    Physica Status Solidi

    (2008)
  • M. Colina et al.

    DNA deposition through laser-induced forward transfer

    Biosensors and Bioelectronics

    (2006)
  • M. Colina et al.

    Laser-induced forward transfer of liquids: study of the droplet ejection process

    Journal of Applied Physics

    (2006)
  • M.S. Brown et al.

    Time-resolved dynamics of laser-induced micro-jets from thin liquid films

    Microfluidics and Nanofluidics

    (2011)
  • M. Schena et al.

    Quantitative monitoring of gene expression patterns with a complementary DNA microarray

    Science

    (1995)
  • Cited by (17)

    • Laser Induced Forward Transfer (LIFT) of nano-micro patterns for sensor applications

      2017, Microelectronic Engineering
      Citation Excerpt :

      Slight variations of the aforementioned factors lead to a change in the capacitance of the device and therefore to a measurable signal. Laser printing has been applied for the fabrication of capacitive sensors as in [75], where our group has demonstrated the pulsed laser printing of thiol-modified oligonucleotides on the surface of 3-glycidoxypropyltrimethoxysilane (GOPTS)-functionalized thin low temperature oxide (LTO)/Si membranes for the development of a label-free capacitive biosensor (see Fig. 12). The typical response of the biosensor arrays was tested upon hybridization with probes fully complementary to the target and the deflection of the membranes was calibrated, while fluorescence microscopy also confirmed the successful hybridization events.

    • Heavy metal ion detection using DNAzyme-modified platinum nanoparticle networks

      2017, Sensors and Actuators, B: Chemical
      Citation Excerpt :

      The sequence of the substrate strand was chimeric, bearing a ribonucleotide at the 10th position of the DNA strand. For the deposition of the DNAzymes the Laser Induced Forward Transfer technique (LIFT) was used [36], ensuring that only the active area of the sensors is covered with catalytic strands (interdigitated electrodes surface area). 6-Mercapto-1-hexanol (MCH) was used in a 1.0 mM solution in deionized water to remove any non-specifically bound catalytic strands from the surface.

    • Laser induced forward transfer of Ag nanoparticles ink deposition and characterization

      2014, Applied Surface Science
      Citation Excerpt :

      In this context, we investigated the influence of the laser fluence on the printed droplets morphology (reproducibility, spatial resolution) and analysed the resistivity and microstructural evolution of Ag NPs features as a function of annealing temperature. The liquid phase LIFT process used in this work has been analytically described previously [23]. The laser used for our experiments is a pulsed Nd:YAG laser operating at 266 nm with a pulse duration of 10 ns.

    • Surface stress-based biosensors

      2014, Biosensors and Bioelectronics
      Citation Excerpt :

      When selective chemical/biochemical reactions occur between the target and probe molecules on the sensor surface, the changes in the intermolecular forces induce a surface stress change which causes the membrane to curve. Membranes offer many advantages over cantilevers, for example, sample isolation from the detection system and easy electronic readout, such as capacitive detection (Chatzipetrou et al., 2013; Satyanarayana, 2005; Chatzandroulis et al., 2004). But, for a given sensor dimension, membranes are less compliant than cantilevers which results in lower sensitivity.

    • Laser-Induced Forward Transfer for Biosensor Application

      2024, Mechanical Engineering in Biomedical Applications Bio-3D Printing, Biofluid Mechanics, Implant Design, Biomaterials, Computational Biomechanics, Tissue Mechanics
    View all citing articles on Scopus
    View full text