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Hierarchical thin film architectures for enhanced sensor performance: liquid crystal-mediated electrochemical synthesis of nanostructured imprinted polymer films for the selective recognition of bupivacaine.

Suriyanarayanan S, Nawaz H, Ndizeye N, Nicholls IA - Biosensors (Basel) (2014)

Bottom Line: Nanostructured bupivacaine-selective molecularly imprinted 3-aminophenylboronic acid-p-phenylenediamine co-polymer (MIP) films have been prepared on gold-coated quartz (Au/quartz) resonators by electrochemical synthesis under cyclic voltammetric conditions in a liquid crystalline (LC) medium (triton X-100/water).Detection was possible at 100 nM (30 ng/mL), and discrimination of bupivacaine from closely related structural analogs was readily achieved as reflected in the corresponding stability constants of the MIP-analyte complexes.The facile fabrication and significant enhancement in sensor sensitivity together highlight the potential of this LC-based imprinting strategy for fabrication of polymeric materials with hierarchical architectures, in particular for use in surface-dependent application areas, e.g., biomaterials or sensing.

View Article: PubMed Central - PubMed

Affiliation: Bioorganic and Biophysical Chemistry Laboratory, Linnæus University Centre for Biomaterials Chemistry and Department of Chemistry and Biomedical Sciences, Linnæus University, SE-391 82 Kalmar, Sweden; E-Mails: esusu@lnu.se (S.S.), nawazhazrat@gmail.com (H.N.); natacha.ndizeye@lnu.se (N.N.).

ABSTRACT
Nanostructured bupivacaine-selective molecularly imprinted 3-aminophenylboronic acid-p-phenylenediamine co-polymer (MIP) films have been prepared on gold-coated quartz (Au/quartz) resonators by electrochemical synthesis under cyclic voltammetric conditions in a liquid crystalline (LC) medium (triton X-100/water). Films prepared in water and in the absence of template were used for control studies. Infrared spectroscopic studies demonstrated comparable chemical compositions for LC and control polymer films. SEM studies revealed that the topologies of the molecularly imprinted polymer films prepared in the LC medium (LC-MIP) exhibit discernible 40 nm thick nano-fiber structures, quite unlike the polymers prepared in the absence of the LC-phase. The sensitivity of the LC-MIP in a quartz crystal microbalance (QCM) sensor platform was 67.6 ± 4.9 Hz/mM under flow injection analysis (FIA) conditions, which was ≈250% higher than for the sensor prepared using the aqueous medium. Detection was possible at 100 nM (30 ng/mL), and discrimination of bupivacaine from closely related structural analogs was readily achieved as reflected in the corresponding stability constants of the MIP-analyte complexes. The facile fabrication and significant enhancement in sensor sensitivity together highlight the potential of this LC-based imprinting strategy for fabrication of polymeric materials with hierarchical architectures, in particular for use in surface-dependent application areas, e.g., biomaterials or sensing.

No MeSH data available.


Related in: MedlinePlus

Cyclic voltammograms for the electrochemical co-polymerization of 3-APBA (2, 5 mM) and p-PD (3, 25 mM), in the presence (A) and absence (B) of 1 mM bupivacaine (1), in Triton X 100-water lytotropic liquid crystalline medium, containing 0.2 M Na2SO4 at pH 8.5, on the gold coated quartz electrode. Potential scan rate was 0.05 V/s. Curves 1 and 2 denote the first and fifth cycle of the cyclic voltammogram.
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biosensors-04-00090-f001: Cyclic voltammograms for the electrochemical co-polymerization of 3-APBA (2, 5 mM) and p-PD (3, 25 mM), in the presence (A) and absence (B) of 1 mM bupivacaine (1), in Triton X 100-water lytotropic liquid crystalline medium, containing 0.2 M Na2SO4 at pH 8.5, on the gold coated quartz electrode. Potential scan rate was 0.05 V/s. Curves 1 and 2 denote the first and fifth cycle of the cyclic voltammogram.

Mentions: The liquid crystalline medium was prepared following established procedures [6] by heating triton X-100 (42%, v/v) in water to 50 °C under constant stirring to afford an isotropic phase. The mixture is then allowed to cool slowly to room temperature to form lyotrophic liquid crystalline phase. Polymerization reaction components; template (1) and the cross-linking functional monomers 1,3-aminophenylboronic acid (2, 3-APBA) and p-phenylenediamine (3, p-PD), were then mixed before being added to the LC medium. This particular polymer system was selected on the basis of results of another study that shall be communicated in elsewhere. Polymerization was performed CV. Figure 1A shows the CV curve for the copolymerization of 2 and 3 in the presence of the template (1) using Na2SO4 as supporting electrolyte on the Au/quartz electrode. The potential of the working Au/quartz electrode was ramped from −0.5 to 1.5 V at a 50 mV/s scan rate. In the anodic scan of the first cycle (Curve 1, in Figure 1A), broad peaks around 0.5 V and 0.75 V can be attributed for the oxidation of 3-APBA and p-PD monomers to form radical cations [29,30,31,32]. Combined oxidation of bipolaron state of these radical cations is observed as a shoulder at 1.3 V, corresponding to the copolymerization [33,34]. The build up of the polymer film on the electrode surface is seen as a drastic decrease in the peak currents, for the oxidation of radical cations (Curve 2 in Figure 1A), owing to the hindered diffusion of the monomers to the electrode surface through. Growth of the pair of redox peaks at 0.74 V and 0.3 V, corresponding to the reduction and oxidation of the co-polymer film, respectively, further support this conclusion. A uniformly reddish brown gold electrode coated surface is obtained. For comparison, a reference polymer film (REF) was prepared identically, though in the absence of template. The similarities of the CV curve profiles from the preparation of the REF and MIP films discounts the possible that oxidation of bupivacaine takes place under the polymerization.


Hierarchical thin film architectures for enhanced sensor performance: liquid crystal-mediated electrochemical synthesis of nanostructured imprinted polymer films for the selective recognition of bupivacaine.

Suriyanarayanan S, Nawaz H, Ndizeye N, Nicholls IA - Biosensors (Basel) (2014)

Cyclic voltammograms for the electrochemical co-polymerization of 3-APBA (2, 5 mM) and p-PD (3, 25 mM), in the presence (A) and absence (B) of 1 mM bupivacaine (1), in Triton X 100-water lytotropic liquid crystalline medium, containing 0.2 M Na2SO4 at pH 8.5, on the gold coated quartz electrode. Potential scan rate was 0.05 V/s. Curves 1 and 2 denote the first and fifth cycle of the cyclic voltammogram.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4264373&req=5

biosensors-04-00090-f001: Cyclic voltammograms for the electrochemical co-polymerization of 3-APBA (2, 5 mM) and p-PD (3, 25 mM), in the presence (A) and absence (B) of 1 mM bupivacaine (1), in Triton X 100-water lytotropic liquid crystalline medium, containing 0.2 M Na2SO4 at pH 8.5, on the gold coated quartz electrode. Potential scan rate was 0.05 V/s. Curves 1 and 2 denote the first and fifth cycle of the cyclic voltammogram.
Mentions: The liquid crystalline medium was prepared following established procedures [6] by heating triton X-100 (42%, v/v) in water to 50 °C under constant stirring to afford an isotropic phase. The mixture is then allowed to cool slowly to room temperature to form lyotrophic liquid crystalline phase. Polymerization reaction components; template (1) and the cross-linking functional monomers 1,3-aminophenylboronic acid (2, 3-APBA) and p-phenylenediamine (3, p-PD), were then mixed before being added to the LC medium. This particular polymer system was selected on the basis of results of another study that shall be communicated in elsewhere. Polymerization was performed CV. Figure 1A shows the CV curve for the copolymerization of 2 and 3 in the presence of the template (1) using Na2SO4 as supporting electrolyte on the Au/quartz electrode. The potential of the working Au/quartz electrode was ramped from −0.5 to 1.5 V at a 50 mV/s scan rate. In the anodic scan of the first cycle (Curve 1, in Figure 1A), broad peaks around 0.5 V and 0.75 V can be attributed for the oxidation of 3-APBA and p-PD monomers to form radical cations [29,30,31,32]. Combined oxidation of bipolaron state of these radical cations is observed as a shoulder at 1.3 V, corresponding to the copolymerization [33,34]. The build up of the polymer film on the electrode surface is seen as a drastic decrease in the peak currents, for the oxidation of radical cations (Curve 2 in Figure 1A), owing to the hindered diffusion of the monomers to the electrode surface through. Growth of the pair of redox peaks at 0.74 V and 0.3 V, corresponding to the reduction and oxidation of the co-polymer film, respectively, further support this conclusion. A uniformly reddish brown gold electrode coated surface is obtained. For comparison, a reference polymer film (REF) was prepared identically, though in the absence of template. The similarities of the CV curve profiles from the preparation of the REF and MIP films discounts the possible that oxidation of bupivacaine takes place under the polymerization.

Bottom Line: Nanostructured bupivacaine-selective molecularly imprinted 3-aminophenylboronic acid-p-phenylenediamine co-polymer (MIP) films have been prepared on gold-coated quartz (Au/quartz) resonators by electrochemical synthesis under cyclic voltammetric conditions in a liquid crystalline (LC) medium (triton X-100/water).Detection was possible at 100 nM (30 ng/mL), and discrimination of bupivacaine from closely related structural analogs was readily achieved as reflected in the corresponding stability constants of the MIP-analyte complexes.The facile fabrication and significant enhancement in sensor sensitivity together highlight the potential of this LC-based imprinting strategy for fabrication of polymeric materials with hierarchical architectures, in particular for use in surface-dependent application areas, e.g., biomaterials or sensing.

View Article: PubMed Central - PubMed

Affiliation: Bioorganic and Biophysical Chemistry Laboratory, Linnæus University Centre for Biomaterials Chemistry and Department of Chemistry and Biomedical Sciences, Linnæus University, SE-391 82 Kalmar, Sweden; E-Mails: esusu@lnu.se (S.S.), nawazhazrat@gmail.com (H.N.); natacha.ndizeye@lnu.se (N.N.).

ABSTRACT
Nanostructured bupivacaine-selective molecularly imprinted 3-aminophenylboronic acid-p-phenylenediamine co-polymer (MIP) films have been prepared on gold-coated quartz (Au/quartz) resonators by electrochemical synthesis under cyclic voltammetric conditions in a liquid crystalline (LC) medium (triton X-100/water). Films prepared in water and in the absence of template were used for control studies. Infrared spectroscopic studies demonstrated comparable chemical compositions for LC and control polymer films. SEM studies revealed that the topologies of the molecularly imprinted polymer films prepared in the LC medium (LC-MIP) exhibit discernible 40 nm thick nano-fiber structures, quite unlike the polymers prepared in the absence of the LC-phase. The sensitivity of the LC-MIP in a quartz crystal microbalance (QCM) sensor platform was 67.6 ± 4.9 Hz/mM under flow injection analysis (FIA) conditions, which was ≈250% higher than for the sensor prepared using the aqueous medium. Detection was possible at 100 nM (30 ng/mL), and discrimination of bupivacaine from closely related structural analogs was readily achieved as reflected in the corresponding stability constants of the MIP-analyte complexes. The facile fabrication and significant enhancement in sensor sensitivity together highlight the potential of this LC-based imprinting strategy for fabrication of polymeric materials with hierarchical architectures, in particular for use in surface-dependent application areas, e.g., biomaterials or sensing.

No MeSH data available.


Related in: MedlinePlus