The Convenience of Polydopamine in Designing SERS Biosensors with a Sustainable Prospect for Medical Application

Effect of DNA Aptamer Concentration on the Stability of PDA Nanoparticle-based Electrochemical Biosensor to Detect Glycated Albumin

BACKGROUND/AIM

The glycated albumin (GA), a potential biomarker for monitoring diabetes mellitus, reflects short-term glycemia and is not influenced by conditions that falsely alter hemoglobin A1c (HbA1c) levels. This study presents a comprehensive evaluation of DNA aptamer-functionalized polydopamine nanoparticles (PDA NPs) for developing a stable biosensor targeting GA.

MATERIALS AND METHODS

DNA aptamers, conjugated to PDA NPs at varying aptamer concentrations (0.05, 0.5, and 5 μM), were systematically analyzed to understand their impact on the morphological, electrochemical behavior, and stable responses of the biosensor.

RESULTS

Morphological assessments using transmission electron microscopy, scanning electron microscopy, and atomic force microscopy confirmed the stability of PDA NPs after conjugation with aptamers. Electrochemical characterization demonstrated enhanced electron transfer efficiency at an optimal aptamer concentration (0.5 μM) for GA detection while stability testing over 30 days indicated sustained sensor functionality.

CONCLUSION

The PDA-0.5 μM aptamer conjugations balance structural integrity, and stability, emphasizing the importance of aptamer concentration optimization for practical biosensor applications.

Metal-polydopamine coordinated coatings on titanium surface: enhancing corrosion resistance and biological property

Previous studies on polydopamine (PDA)-modified titanium implants have primarily focused on single-metal-ion systems (e.g., Ag+, Cu2+, or Zn2+), while overlooking the interplay between corrosion resistance, antioxidant retention, and antimicrobial efficacy under clinically relevant oxidative conditions. Here, we present a comparative analysis of Ag-, Cu-, and Zn-integrated PDA coatings fabricated via a two-step coordination strategy, addressing these limitations through systematic multi-parameter evaluation. Unlike prior studies, this study reveals distinct metal-PDA interaction mechanisms: XPS/EDS analyses confirm Zn2+ and Cu2+ form coordination complexes with PDA's catechol groups, whereas Ag+ undergoes reduction to metallic nanoparticles (Ag0), leading to divergent ion-release profiles (Zn2+ > Cu2+ > Ag+) and biofunctional outcomes. Electrochemical testing under H2O2-simulated oxidative stress demonstrates Zn-PDA coatings exhibit superior corrosion resistance (polarization resistance: 4330 vs. 3900 and 2850 kΩ cm2 for Cu-PDA and Ag-PDA, respectively), while Ag-PDA achieves the highest antibacterial efficacy (>95% reduction against S. aureus and E. coli). Notably, Zn/Cu-PDA coatings retain >80% of PDA's intrinsic antioxidant capacity, in contrast to Ag-PDA, which exhibits significant antioxidant depletion due to redox interference. In vivo rat models further differentiate our approach: all coatings show comparable soft-tissue integration and systemic biosafety, contrasting with earlier reports of Ag-induced cytotoxicity. By elucidating metal-specific performance trade-offs and establishing a design framework to balance corrosion resistance, ROS scavenging, and antimicrobial activity, this work advances clinically adaptable strategies for enhancing peri-implant tissue stability.

Electrospun Nanofibers from Plant Natural Products: A New Approach Toward Efficient Wound Healing

Globally, wound care has become a significant burden on public health, with annual medical costs reaching billions of dollars, particularly for the long-term treatment of chronic wounds. Traditional treatments, such as gauze and bandages, often fail to provide an ideal healing environment due to their lack of effective biological activity. Consequently, researchers have increasingly focused on developing new dressings. Among these, electrospinning technology has garnered considerable attention for its ability to produce nano-scale fine fibers. This new type of dressing, with its unique physical and chemical properties-especially in enhancing breathability, increasing specific surface area, optimising porosity, and improving flexibility-demonstrates significant advantages in promoting wound healing, reducing the risk of infection, and improving overall healing outcomes. Additionally, the application of natural products from plants in electrospinning technology further enhances the effectiveness of dressings. These natural products not only exhibit good biocompatibility but are also rich in pharmacologically active ingredients, such as antibacterial, anti-inflammatory, and antioxidant compounds. They can serve as both the substrate for nanofibers and as bioactive components, effectively promoting cell proliferation and tissue regeneration, thereby accelerating wound healing and reducing the risk of complications. This article reviews the application of plant natural product nanofibers prepared by electrospinning technology in wound healing, focussing on the development and optimisation of these nanofibers, discussing the advantages and challenges of using plant natural products in this technology, and outlining future research directions and application prospects in this field.

Noble metal-free SERS: mechanisms and applications

Surface-enhanced Raman scattering (SERS) is a very important tool in vibrational spectroscopy. The coupling of nanomaterials induces local surface plasmon resonance (LSPR), which contributes greatly to SERS. Due to its remarkable sensitivity in trace detection, SERS has gained prominence in the fields of catalysis, biosensors, drug tracking, and optoelectronic devices. SERS activity is believed to be closely related to the LSPR and charge transfer (CT) of the material. Noble metal nanostructures have been commonly used as SERS-active substrates due to their strong local electric fields and relatively mature preparation, application, and enhancement mechanisms. In recent years, SERS research based on semiconductor materials has attracted significant attention because semiconductor materials have advantages such as repeatable preparation, simple pretreatment, stable SERS spectra and superior biocompatibility, stability, and reproducibility. Semiconductor-based SERS has the potential to enrich SERS theory and applications. Thus, the development of semiconductor materials will introduce a new epoch for SERS-based research. In this review, we outline the two main kinds of semiconductor SERS-active substrates: inorganic and organic semiconductor SERS-active substrates. We also provide an overview of the SERS mechanism for different kinds of materials and SERS-based applications.