Detection of trace heavy metal ions in water by nanostructured porous Si biosensors

Abstract

A generic biosensing platform, based on nanostructured porous Si (PSi), Fabry-Pérot thin films, for label-free monitoring of heavy metal ions in aqueous solutions by enzymatic activity inhibition, is described. First, we show a general detection assay by immobilizing horseradish peroxidase (HRP) within the oxidized PSi nanostructure and monitor its catalytic activity in real time by reflective interferometric Fourier transform spectroscopy. Optical studies reveal the high specificity and sensitivity of the HRP-immobilized PSi towards three metal ions (Ag(+) > Pb(2+) > Cu(2+)), with a detection limit range of 60-120 ppb. Next, we demonstrate the concept of specific detection of Cu(2+) ions (as a model heavy metal) by immobilizing Laccase, a multi-copper oxidase, within the oxidized PSi. The resulting biosensor allows for specific detection and quantification of copper ions in real water samples by monitoring the Laccase relative activity. The optical biosensing results are found to be in excellent agreement with those obtained by the gold standard analytical technique (ICP-AES) for all water samples. The main advantage of the presented biosensing concept is the ability to detect heavy metal ions at environmentally relevant concentrations using a simple and portable experimental setup, while the specific biosensor design can be tailored by varying the enzyme type.

Enzyme immobilisation on poly-l-lysine-containing calcium phosphate particles for highly sensitive glucose detection

“…8 In addition, Shtenberg et al studied nanostructured porous Si sensors for the detection of heavy metal ions in water by immobilising horseradish peroxidase, laccase and multi-copper oxidase. 9 Glucose oxidase (GOX) is a key enzyme for biosensors and can catalyse the oxidation of glucose. For example, GOX can be used as a blood sugar level sensor for diabetic patients by measuring the glucose concentration in their blood.…”

An Innovative Metal Ions Sensitive “Test Paper” Based on Virgin Nanoporous Silicon Wafer: Highly Selective to Copper(II)

“…In our previous work, a novel voltammetric sensor based on 3-aminopropyltriethoxysilanes (APTES) functionalized porous silicon was elaborated for sensing Ag + in aqueous solution23. Segal et al 24. have designed and fabricated optical biosensing platform based on horseradish peroxidase (HRP) and laccase immobilized PSi nanostructures, it allows for real-time monitoring of heavy metal ions by enzymatic activity inhibition.…”

Low Dimensional Nanostructures: Measurement and Remediation Technologies Applied to Trace Heavy Metals in Water

“…Lacasse is an enzyme, a multi-copper oxidase, immobilized within the oxidized nanostructured porous silicon. The Laccase-based biosensor exhibited a lower detection limit of 1.30 μM, smaller than other values [41].…”