Surface Functionalization toward Biosensing via Free-Standing Si-OH Bonds on Nonoxidized Silicon Surfaces

Biodegradable, water-resistant, smart cellulose-based drinking straws from agricultural biomass with detection of adulterants in beverages

Drinking straws due to their non-degradability, large consumption, and poor recyclability, pose a great risk to the environment and human health. Leaf stalk from papaya biomass was modified strategically via delignification and silanization for fabricating drinking straws. The straws show high water resistance (∼8 h), mechanical strength (50.1 MPa tensile strength, 6.7 MPa flexural strength, and 26.7 MPa compressive strength), hydrophobicity (contact angle ∼90.2°), solvothermal stability (0-80 °C), migration within standard limits (<60 mg/kg), low swelling (∼3.83 times) and anti-fizzing. The papaya straws post-functionalization were biodegradable (∼28 days) with lower ecological impacts. The smart straws show color change with pH variation (3-11), making them suitable for detecting spoilage and urea adulteration (1 mg/ml) in beverages and milk samples, respectively. The straws showed higher performance than paper straws with low water resistance (∼30 mins), mechanical strength (∼14 MPa), fizzing, and plastic straws with low strength (∼22 MPa) and non-biodegradability. The study provides a facile, scalable, environment-friendly, strategy for preparing high-performance straws from renewable biomass with improved properties and the ability to detect spoilage in fruit juices and milk beverages.

A flexible photoelectrochemical aptasensor using heterojunction architecture of α-Fe2O3/d-C3N4 for ultrasensitive detection of penbritin

The performance of photoelectrochemical (PEC) analysis system relies closely on the properties of the photoelectric electrodes. It is of great significance to integrate photoactive materials with flexible substrates to construct ultra-sensitive PEC sensors for practical application. This work reports a novel photoelectrode developed by immobilizing α-Fe₂O₃ nanoparticles (NPs)/defect-rich carbon nitride (d-C₃N₄), an excellent Z-scheme heterojunction photoelectric material, onto three-dimensional (3D) flexible carbon fiber textile. Specifically, 3D hierarchical structure of flexible carbon fiber textile provides larger specific surface area and higher mechanical strength than traditional electrodes, resulting in more reaction sites and faster reaction kinetics to achieve signal amplification. Simultaneously, α-Fe₂O₃/d-C₃N₄ Z-scheme heterojunction exhibits enhanced light absorption capability and high redox ability, thus dramatically improving the PEC performance. This photoelectrode was used to construct a flexible PEC aptasensor for ultrasensitive detection of penbritin, demonstrating excellent performance in terms of wide linear range (0.5 pM-50 nM), low detection limit (0.0125 pM) and high stability. The design principle is applicable to the manufacture of other photoelectric sensing systems, which provides an avenue for the development of portable environmental analysis and field diagnostics equipment.