Dual-Purpose Phononic-Chimneys for Ambient Zeptogram Mass Sensing: Leveraging Z-Axis Gold Vents as Bio-Functionalization Receptors.

Standard silicon Nanoelectromechanical Systems (NEMS) mass spectrometers are fundamentally limited by their thermodynamic noise floor. The Joule heating required for electrical piezoresistive readout induces a Temperature Coefficient of Elasticity (TCE) drift that actively masks zeptogram-scale mass perturbations, traditionally necessitating complex cryogenic isolation. Building upon our previously validated Zero-TCE Phononic-Chimney architecture which clamps thermal drift via Z-axis heat sinks we propose a novel 8-body vacuum-to-liquid microfluidic bridge. By extending Gold (Au) chimneys through a hermetic Aluminum Nitride (AlN) Cap Wafer to act as "blind vias," the thermal vents simultaneously serve as high-surface-area bio-functionalization receptors submerged in a fluidic channel. Fully coupled Finite-Difference Time-Domain (FDTD) multiphysics simulations explicitly penalized for Kapitza interfacial resistance confirm a peak core thermal clamp of 311.23 K( T = 1.08 K). Subsequent Eigenfrequency perturbation analysis confirms this Zero-TCE baseline unlocks a massive, measurable resonance shift f = 1.39 MHz under high-density calibration loading). This dynamic responsivity, entirely isolated from thermal noise, mathematically proves the viability of this architecture for real-time, ambient-temperature oncology and virology biomarker detection.