Multifunctional core-shell nanoparticles: discovery of previously invisible biomarkers

J Am Chem Soc. 2011 Nov 30;133(47):19178-88. doi: 10.1021/ja207515j. Epub 2011 Nov 3.


Many low-abundance biomarkers for early detection of cancer and other diseases are invisible to mass spectrometry because they exist in body fluids in very low concentrations, are masked by high-abundance proteins such as albumin and immunoglobulins, and are very labile. To overcome these barriers, we created porous, buoyant, core-shell hydrogel nanoparticles containing novel high affinity reactive chemical baits for protein and peptide harvesting, concentration, and preservation in body fluids. Poly(N-isopropylacrylamide-co-acrylic acid) nanoparticles were functionalized with amino-containing dyes via zero-length cross-linking amidation reactions. Nanoparticles functionalized in the core with 17 different (12 chemically novel) molecular baits showed preferential high affinities (K(D) < 10(-11) M) for specific low-abundance protein analytes. A poly(N-isopropylacrylamide-co-vinylsulfonic acid) shell was added to the core particles. This shell chemistry selectively prevented unwanted entry of all size peptides derived from albumin without hindering the penetration of non-albumin small proteins and peptides. Proteins and peptides entered the core to be captured with high affinity by baits immobilized in the core. Nanoparticles effectively protected interleukin-6 from enzymatic degradation in sweat and increased the effective detection sensitivity of human growth hormone in human urine using multiple reaction monitoring analysis. Used in whole blood as a one-step, in-solution preprocessing step, the nanoparticles greatly enriched the concentration of low-molecular weight proteins and peptides while excluding albumin and other proteins above 30 kDa; this achieved a 10,000-fold effective amplification of the analyte concentration, enabling mass spectrometry (MS) discovery of candidate biomarkers that were previously undetectable.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acrylamides / chemical synthesis
  • Acrylamides / chemistry*
  • Biomarkers, Tumor / blood
  • Biomarkers, Tumor / chemistry*
  • Coloring Agents / chemistry
  • Growth Hormone / urine
  • Humans
  • Hydrogel, Polyethylene Glycol Dimethacrylate / chemical synthesis
  • Hydrogel, Polyethylene Glycol Dimethacrylate / chemistry
  • Molecular Structure
  • Nanoparticles / chemistry*
  • Particle Size
  • Peptides / chemistry
  • Polymers / chemical synthesis
  • Polymers / chemistry*
  • Porosity
  • Proteins / chemistry
  • Surface Properties


  • Acrylamides
  • Biomarkers, Tumor
  • Coloring Agents
  • N-isopropylacrylamide-acrylic acid copolymer
  • Peptides
  • Polymers
  • Proteins
  • Hydrogel, Polyethylene Glycol Dimethacrylate
  • Growth Hormone