Search for: All records

Abstract Biofilms, notorious for their recalcitrance and dynamic behavior, pose a persistent threat to public health. However, existing diagnostic tools fall short in providing in situ, spatiotemporal biochemical insights into dynamic biofilm behavior. To address this, we have developed zwitterionic nanoplasmonic bio-meshes that combine the antifouling attributes of zwitterionic L-cysteine, the biocompatibility of polymeric meshes, and the ultrasensitive, uniform, and stable surface-enhanced Raman spectroscopy (SERS) response of plasmonic nanocavity arrays. This platform delivers improved SERS performance in human serum compared to controls without L-cysteine functionalization, achieving a clinically-relevant limit of detection of 5.6 nM for pyocyanin in undiluted human serum. Moreover, the platform enables real-time, in situ spatiotemporal SERS monitoring ofP. aeruginosabiofilms over 48 h in culture media-agar backgrounds, revealing distinct pyocyanin secretions dynamics in wild-type and hyperbiofilm mutant strains. We envision that this capability to non-invasively monitor biofilm metabolite secretion dynamics can empower next-generation biofilm diagnostics and anti-biofilm therapies. 

This study presents antifouling nanoplasmonic bio-meshes forin situspatiotemporal SERS monitoring ofP. aeruginosabiofilms. The bio-meshes combine zwitterionic L-cysteine antifouling properties with biocompatible polymeric meshes and sensitive SERS nanocavity arrays. This platform enables ultrasensitive pyocyanin detection in undiluted serum and reveals pyocyanin dynamics inP. aeruginosabiofilms, highlighting the link between metabolite secretion and cyclic di-GMP signaling. 

Multiresonant nanolaminate nanopillar arrays (NLNPAs) enable broadband second- and third-harmonic generation and enhanced refractive index sensing with superior sensitivity, establishing NLNPAs as a versatile platform for advanced photonic applications. 

This study introduces biomimetic transparent nanoplasmonic microporous mesh (BTNMM) devices fabricated via reverse nanoimprint lithography. These devices offer spatiotemporal multimodal SERS measurements for bio-interfaced applications, enabling targeted pH sensing and molecular profiling of microbial biofilms. 

Metallic nanostructures supporting surface plasmon modes can concentrate optical fields, and enhance luminescence processes from the metal surface at plasmonic hotspots. Such nanoplasmonic metal luminescence contributes to the spectral background in surface-enhanced Raman spectroscopy (SERS) measurements and is helpful in bioimaging, nano-thermometry, and chemical reaction monitoring applications. Despite increasing interest in nanoplasmonic metal luminescence, little attention has been paid to investigating its dependence on voltage modulation. Also, the hyphenated electrochemical surface-enhanced Raman spectroscopy (EC-SERS) technique typically ignores voltage-dependent spectral background information associated with nanoplasmonic metal luminescence due to limited mechanistic understanding and poor measurement reproducibility. Here, we report a combined experiment and theory study on dynamic voltage-modulated nanoplasmonic metal luminescence from hotspots at the electrode-electrolyte interface using multiresonant nanolaminate nano-optoelectrode arrays. Our EC-SERS measurements under 785 nm laser excitation demonstrate that short-wavenumber nanoplasmonic metal luminescence associated with plasmon-enhanced electronic Raman scattering (PE-ERS) exhibits a negative voltage modulation slope (up to ≈30 % V-1) in physiological ionic solutions. Furthermore, we have developed a phenomenological model to intuitively capture plasmonic, electronic, and ionic characteristics at the metal-electrolyte interface to understand the observed dependence of the PE-ERS voltage modulation slope on voltage polarization and ionic strength. The current work represents a critical step toward the general application of nanoplasmonic metal luminescence signals in optical voltage biosensing, hybrid optical-electrical signal transduction, and interfacial electrochemical monitoring.