This　work　reports　the　proof-of-concept　of　novel　and　powerful　enzyme-free　voltammetric　aptasensor　of　colorectal　cancer-related　carcinoembryonic　antigen　(CEA)　without　the　participation　of　any　antibodies.　The　aptasensor　was　prepared　by　means　of　immobilizing　thiolated　CEA　aptasensor　on　gold　nanoparticle-deposited　glassy　carbon　electrode.　Thionine-doped　silica　nanoparticles　were　synthesized　via　reverse　micelle　method　and　functionalized　with　p-aminophenylboronic　acid　by　the　epoxy-amino　reaction　for　specific　conjugation　of　subsequent　CEA　glycoprotein.　In　the　presence　of　target　CEA,　the　analyte　initially　reacted　with　immobilized　aptamer　on　the　electrode　to　generate　an　aptamer-CEA　complex.　Then,　phenylboronic　acid　immobilized　on　silica　nanoparticle　specifically　recognized　with　CEA　glycoprotein　based　on　sugar-boronic　acid　interaction　to　form　a　sandwich-type　complex　on　the　electrode.　Within　the　applied　potentials,　the　doped　thionine　molecules　into　the　silica　nanoparticles　were　used　as　the　electron　mediators　to　produce　well-defined　voltammetric　signals　(vs.　Ag/AgCl).　Under　optimum　conditions,　the　voltammetric　peak　current　increased　linearly　within　the　CEA　concentration　in　the　range　from　1.0　pg　mL(-1)　to　10　ng　mL(-1),　and　the　limit　of　detection　was　0.49　pg　mL(-1)　at　3d.　A　repeatability　and　intermediate　precision　of　＜=　8.7%　was　accomplished　at　CEA　levels　in　the　batch-to-batch　mode.　The　method　was　highly　specific　for　CEA　over　other　disease-related　biomarkers.　The　accuracy　and　inter-laboratory　validation　of　this　system　were　evaluated　for　target　CEA　detection　in　human　serum　specimens,　and　the　results　were　in　accordance　with　those　obtained　by　a　commercial　ELISA.　(C)　2020　Elsevier　B.V.　All　rights　reserved.