Synthesis and Characterization of a Pyrrole−Alginate Conjugate and Its Application in a Biosensor Construction

Abstract

N-(3-Aminopropyl)pyrrole was covalently coupled with alginate in an aqueous-phase reaction by means of carbodiimide-mediated activation chemistry to provide a pyrrole-alginate conjugate for subsequent use in biosensor applications. The pyrrole-alginate conjugate was quantified by UV spectroscopy at 230 nm, by an HPSEC-MALLS analytical method, as well as by FTIR and 13C NMR spectroscopies. The new pyrrole-alginate conjugate was used for the immobilization of polyphenol oxidase (PPO) onto an electrode surface by physical entrapment resulting from the gellification process and electrochemical polymerization of the pyrrole groups. The efficiency of this cross-linking approach (chemical and electrochemical) was investigated by comparing the amount of enzyme released from polypyrrole-alginate and regular alginate. In addition, biosensors were prepared by entrapment of the PPO in polypyrrole-alginate and regular alginate matrixes and their performance for the amperometric determination of catechol chosen as a model analyte was examined, yielding a sensitivity of 350 and 80 microA M(-1) cm(-2), respectively, for polypyrrole-alginate and alginate biosensors.

Highly sensitive amperometric biosensors for phenols based on polyaniline–ionic liquid–carbon nanofiber composite

“…The linear range spanned the 4-order concentration of catechol from 4.0 × 10 −10 to 2.1 × 10 −6 M with a correlation coefficient of 0.999, and a detection limit of 0.1 nM, at which the amperometric response and the noise were 4.2 and 1.3 nA (S/N ∼ 0.3), respectively. Its sensitivity was 296 ± 4 A M −1 cm −2 , which was much higher than those of tyrosinase biosensor based on polyaniline-polyacrylonitrile composite (2.03 A M −1 cm −2 ) (Xue and Shen, 2002), electrogenerated polypyrrole/carbon paste (4.7 A M −1 cm −2 ) (Mailley et al, 2003), polypyrrole-alginate conjunct (0.350 A M −1 cm −2 ) (Abu- Rabeah et al, 2005), layered double hydroxides (LDH) (7.81 A M −1 cm −2 ) (Shan et al, 2003), graphite-Teflon composite in presence of gold nanoparticles (10.6 A M −1 cm −2 ) (Carralero et al, 2006) and Fe 3 O 4 nanoparticles-chitosan composite (22.84 A M −1 cm −2 ) . The high sensitivity of the Tyr/PANI-IL-CNF biosensor could be attributed to the combination of the advantages of three components.…”

Amperometric Algal Chlorella vulgaris Cell Biosensors Based on Alginate and Polypyrrole‐Alginate Gels

“…1) as reported [19]: an amount of 0.010 g (0.05 mmol) of N-(3-aminopropyl) pyrrole was added to a solution of alginate (20 mL solution, 0.25 mmol (0.05 g) alginate monomer in 0.1 M 2-[N-morpholino] ethanesulfonic acid (MES) buffer, pH 6.0. The reaction mixture was stirred at room temperature for 10 min to facilitate a homogeneous dispersion of the pyrrole reagent in the reaction solution.…”

“…Since the conductometric biosensors [14] based on entrapment of algae cells Chlorella vulgaris into regular alginates gels have displayed a very limited operational stability, a novel synthetic alginate molecule with better molecular retention properties was designed [19,20]. This molecule is based on grafting pyrrole moieties on alginate which then will allow for a controllable electropolymerization process and a new and putatively more stable configuration on the electrode surface so created.…”

Enzyme‐Based Biosensors: Synthesis and Applications

“…Many of the conventional devices and techniques, including nuclear magnetic resonance [178] , surface plasmon resonance [179] and mass spectrometry [180] , however, requiring time -consuming purifi cation of samples, may lack the ability for multiplexed measurements that are desirable in identifying complex diseases, or may be uncontrollable for easy point -of -care translation [3,175] . In contrast, biosensors enable direct, sensitive, selective, and rapid analysis of biological and chemical species, and thus are widely used in many areas of healthcare and life sciences, ranging from uncovering and diagnosing disease to the discovery and screening of new drugs and biomolecules [20,181,182] . For example, in brain monitoring, l -glutamate is the most widespread excitatory neurotransmitter in the mammalian central nervous system, plays a important role in a broad range of brain functions, and has been implicated in a number of neurological disorders [33,183] .…”