Bioanalytical Applications

Biofunctionalization of nanobiosensor surfaces

We work in implementing different immobilization strategies for all type of biological receptors at the sensor surface in order to achieve robust, reproducible and high performance devices. We work with gold, silicon and glass surfaces according with the sensing technologies developed in the Group. This research line is closely related to each specific bioanalytical application and highly influenced by the nature of target to be detected (i.e. protein, nucleic acids or synthetic molecules) and the media (i.e. buffer, urine, serum, blood, tears, cerebrospinal fluid,..).

The general procedure includes the following steps:

  • Cleaning and chemical activation of the sensor surface (1 and 2)
  • Surface modification based on (i) the preparation of customized surfaces with adequate surface biocompatibility and hydrophilicity in order to minimize the non-specific binding on the surface; (ii) the introduction of the appropriate functionality in order to allow the efficient and reproducible immobilization of the specific receptors and (iii) attachment of the specific recognition element (3) and final detection (4).
  • Adaptation of the protocols for multiplexed analysis, based on the co-immobilization of several receptors on the surface.

 

 

Optical label-free biosensing of proteins and small molecules

Our goal is to apply the different biosensing technologies developed in the Group to the detection of target molecules of clinical and environmental relevance. Our interest ranges from low molecular weight molecules like small pollutants, pesticides or metabolites and large biomolecules like protein biomarkers involved in cancer and other medically relevant diseases. We work preferentially with antibodies as recognition element to perform specific detection with high level of sensitivity, always aimed at detecting the target in real samples (i.e. natural waters, food, or bodily fluids like serum or urine). The influence of complex matrices on the biofunctionalized surface and in the detection assay parameters becomes a key point to be surpassed for the development of a particular application.

Our work is mainly focused on:

  • Designing the best detection format (i.e. direct format or indirect approach). In the direct approach, we do an intensive research to obtain reproducible and well-oriented antibody-coated surfaces with maximum binding efficiency towards target molecule.
  • Optimizing the immobilization of receptors to maximize sensitivity, reproducibility and stability of the biofunctionalized surface.
  • Developing the immunoassay and establishing the optimal experimental conditions to analyze the target with the biosensing platform.
  • Studying the behavior of the immunoassay in native media in order to evaluate the viability of the method to detect real samples.

Some of our applications (already done or under development):

  • Determination of pesticides for water monitoring and food control
  • Evaluation of pesticide residues or metabolites in human urine
  • Detection of hormones in human fluids (serum, urine)
  • Determination of protein cancer biomarkers
  • Detection of pathogen bacteria in biological fluids
  • Evaluation of multiple biomarkers related to liver diseases and liver transplant
  • Determination of protein biomarkers related to ocular diseases

Optical label-free biosensing of nucleic acids

Our goal is to apply the different biosensing technology developed in the Group to the detection of nucleic acids with relevancy in the clinical and biotechnological field. We are interested on detection of both DNA and RNA sequences involved in cancer and other medically relevant diseases, including recognition of point mutations and epigenetic biomarkers.

Our work is mainly focused on:

  • Designing the most suitable detection format
  • Optimizing the immobilization of receptors to maximize sensitivity, reproducibility and stability of the biofunctionalized surface.
  • Establishing the optimal experimental conditions to analyze the target with the biosensing platform.
  • Studying the behavior of the nucleic acid capture in native media in order to evaluate the viability of the method to detect real samples.

Some of our applications (already done or under development):

  • Label-free DNA hybridization at nM-pM level
  • Labe-free detection of DNA single-point mutations at gene BRCA-1 for diagnosis of inherited breast cancer
  • Label-free detection of RNA sequences using an innovative triplex-affinity capturing method. It has been applied to identification of pathogens (i.e. Listeria Innocua) and to detect structured RNA sequences.
  • Label-free detection of alternative spliced FAS gene RNA isoforms.
  • Screening of epigenetic modifications such as DNA methylation.