Gold Nanoparticles-Coated SU-8 for Sensitive Fluorescence-Based Detections of DNA

SU-8 epoxy-based negative photoresist has been extensively employed as a structural material for fabrication of numerous biological microelectro-mechanical systems (Bio-MEMS) or lab-on-a-chip (LOC) devices. However, SU-8 has a high autofluorescence level that limits sensitivity of microdevices that use fluorescence as the predominant detection workhorse. Here, we show that deposition of a thin gold nanoparticles layer onto the SU-8 surface significantly reduces the autofluorescence of the coated SU-8 surface by as much as 81% compared to bare SU-8. Furthermore, DNA probes can easily be immobilized on the Au surface with high thermal stability. These improvements enabled sensitive DNA detection by simple DNA hybridization down to 1 nM (a two orders of magnitude improvement) or by solid-phase PCR with sub-picomolar sensitivity. The approach is simple and easy to perform, making it suitable for various Bio-MEMs and LOC devices that use SU-8 as a structural material.

[1]  Nikolay I. Zheludev,et al.  Holographically encoded microparticles for bead-based assays , 2009 .

[2]  B. Barrell,et al.  The genome sequence of the food-borne pathogen Campylobacter jejuni reveals hypervariable sequences , 2000, Nature.

[3]  Martin Dufva,et al.  An inexpensive and simple method for thermally stable immobilization of DNA on an unmodified glass surface: UV linking of poly(T)10-poly(C)10-tagged DNA probes. , 2008, BioTechniques.

[4]  Soumyo Mukherji,et al.  A novel dry method for surface modification of SU-8 for immobilization of biomolecules in Bio-MEMS. , 2007, Biosensors & bioelectronics.

[5]  Naomi J. Halas,et al.  Nanoengineering of optical resonances , 1998 .

[6]  T. Desai,et al.  Off-wafer fabrication and surface modification of asymmetric 3D SU-8 microparticles , 2006, Nature Protocols.

[7]  Mogens Madsen,et al.  Development of a PCR assay suitable for Campylobacter spp. mass screening programs in broiler production , 2001 .

[8]  Sang Jun Sim,et al.  Resonant Rayleigh light scattering response of individual Au nanoparticles to antigen-antibody interaction. , 2009, Lab on a chip.

[9]  Vincent M Rotello,et al.  Detection and identification of proteins using nanoparticle-fluorescent polymer 'chemical nose' sensors. , 2007, Nature nanotechnology.

[10]  Nam-Trung Nguyen,et al.  SU‐8 as a structural material for labs‐on‐chips and microelectromechanical systems , 2007, Electrophoresis.

[11]  C. Mirkin,et al.  The Electrical Properties of Gold Nanoparticle Assemblies Linked by DNA. , 2000, Angewandte Chemie.

[12]  H. Möhwald,et al.  Core−Shell Poly(allyamine hydrochloride)-Pyrene Nanorods Decorated with Gold Nanoparticles , 2011 .

[13]  Nam-Trung Nguyen,et al.  A polymeric piezoelectric micropump based on lamination technology , 2004 .

[14]  Chulhee Kim,et al.  Tunable fluorescent dendron-cyclodextrin nanotubes for hybridization with metal nanoparticles and their biosensory function. , 2008, Angewandte Chemie.

[15]  A. Libchaber,et al.  Single-mismatch detection using gold-quenched fluorescent oligonucleotides , 2001, Nature Biotechnology.

[16]  Sang Jun Sim,et al.  A strategy for sensitivity and specificity enhancements in prostate specific antigen-alpha1-antichymotrypsin detection based on surface plasmon resonance. , 2006, Biosensors & bioelectronics.

[17]  James R. Heath,et al.  Synthesis and Characterization of Hydrophobic, Organically-Soluble Gold Nanocrystals Functionalized with Primary Amines , 1996 .

[18]  Hywel Morgan,et al.  Diffractive micro bar codes for encoding of biomolecules in multiplexed assays. , 2008, Analytical chemistry.

[19]  Mark Bachman,et al.  Photoresist with low fluorescence for bioanalytical applications. , 2007, Analytical chemistry.

[20]  Yi Sun,et al.  A lab-on-a-chip device for rapid identification of avian influenza viral RNA by solid-phase PCR. , 2011, Lab on a Chip.

[21]  A. Boisen,et al.  Immobilisation of DNA to polymerised SU-8 photoresist. , 2006, Biosensors & bioelectronics.

[22]  Anders Wolff,et al.  Dual enlargement of gold nanoparticles: from mechanism to scanometric detection of pathogenic bacteria. , 2011, Small.

[23]  Joel Voldman,et al.  A photopatternable silicone for biological applications. , 2008, Langmuir : the ACS journal of surfaces and colloids.

[24]  Thomas A. Klar,et al.  Long-range fluorescence quenching by gold nanoparticles in a sandwich immunoassay for cardiac troponin T. , 2009, Nano letters.

[25]  A. Heeger,et al.  Beyond superquenching: Hyper-efficient energy transfer from conjugated polymers to gold nanoparticles , 2003, Proceedings of the National Academy of Sciences of the United States of America.