Plasmonic hydrogel nanocomposites with combined optical ...

B. Miranda1,2,*, R. Moretta1, S. De Martino3, P. Dardano1, I. Rea1, C. Forestiere2, L. De Stefano1

1 Institute of Applied Sciences and Intelligent Systems, via P. Castellino 111, Naples, 80131, Italy

2 DIETI, University of Naples “Federico II”, via Claudio 21, Naples, 80125 Italy

3 Materias s.r.l., via N. Protopisani 50, Naples, 80131, Italy

*[email protected]

Plasmonic hydrogel nanocomposites with combined optical and mechanical

properties for biochemical sensing

Outline

• Localized Surface Plasmon Resonance and Metal-Enhanced Fluorescence

• Plasmonic Hydrogels: Design and Optical Characterization

• Dual-Sensing of Streptavidin in PEGDA 10kDa as a Proof of Concept

• Conclusions and Future Perspectives

2

Bruno Miranda, [email protected]

Plasmonic hydrogel nanocomposites with combined optical

and mechanical properties for biochemical sensing

Outline

• Localized Surface Plasmon Resonance and Metal-Enhanced Fluorescence

3




Introduction: LSP Resonance

• Localized surface plasmon resonance

(LSPR): a size and shape-dependent

coherent oscillation of the conduction

electrons of a noble metal nanoparticle

( d << λ ).

• LSPRs exhibit strong field enhancement in

the surroundings of the nanoparticles,

which makes their resonance locally sensitive

to refractive index variations.

• Plasmon: oscillation of electron density with respect to the fixed positive ions in a metal.

S.Maier, Plasmonics: Fundamentals and Application. Springer, 2007;

B. Sepùlveda et al., Nano Today, 2009

Farooq, S. and de Araujo, R.E, Open Journal of Applied Sciences, 2018.

Gold Nanospheres

with increasing size

Silver Nanospheres

with increasing size

4




Introduction: Metal-Enhanced Fluorescence

• Förster resonance energy transfer (FRET) mechanism

• Purcell effect mechanism

• Dual-mechanism

• Metal-Enhanced Fluorescence is a phenomenon dependent on:• the spectral overlap between a fluorescent dye and the plasmon absorbance

• the fluorophore-nanostructure distance z.

B. Miranda et al., ACS Applied Nano Materials, 2020

A. Minopoli et al., Nature Communications, 2021

5




Introduction: Flexible Plasmonic Nanocomposites

“Flexible Plasmonic Nanocomposites”: plasmonic

nanoparticles impregnated over/in flexible solid substrates.

Advantages:

Cost-Effectiveness

High Processability

Adaptable to non-planar substrates

In-situ/In-vivo collection of the samples

Easy integration into more complex systems

Polavarapu et al., Physical Chemistry Chemical Physiscs, 2013

B. Miranda et al., Biosensors, under review, 2021

https://www.theengineer.co.uk/roll-to-

roll-electronic-devices-nano/

6




https://www.theengineer.co.uk/roll-to-roll-electronic-devices-nano/

Outline

• Plasmonic Hydrogels: Design and Optical Characterization

7




Plasmonic Hydrogels: FabricationHydrogels for miniaturized 3D biosensors

Biorecognition elements are adhered onto a 3D architecture

Polyethylene glycol diacrylate (PEGDA)

Excellent matrices for the entrapment of biomolecules

Non-fouling material (useful for complex solutions)

Tunable micropatterning with photolithographic techniques.

Tunable network in terms of mesh size and crosslinking

Colloidal citrate gold nanoparticles (Au-NPs)

Tunable in size and shape

Many surface chemistry protocols have been

optimized

Pedrosa et al., Electroanalysis, 2011; Love et al., Chemical Reviews, 2005;

Rebelo et al., Biosensors and Bioelectronics, 2019;

B. Miranda et al., Journal of Applied Physics, 2021.

.

8




Plasmonic hydrogels: Fabrication and Characterization

B. Miranda et al., 2020 Italian Conference on Optics and Photonics (ICOP), Parma, Italy, IEEE Xplore, 2020

B. Miranda et al., Journal of Applied Physics, 2021

Stirring PolymerizationPEGDA/AuNPs

nanocomposites

Size-dependent colorimetric variations

9




0 2 4 6 8 10

550

552

554

556

558

560

Mean max

Control

Hill type Fit

Mea

n L

SP

Re

son

an

ce

max (

nm

)

Biotin Concentration (mM)

Citrate

displacement

Plasmonic Hydrogels: Functionalization

Citrate AuNPsPEGDA/AuNPs

compositesCysteamine-modified

AuNPs

Biotin-NHS

interaction

Biotin bound

to AuNPs

PEGDA

HydrogelAuNP Citrate Cysteamine BiotinNHS

0,00 0,25 0,50 0,75 1,00 1,25 1,50 1,75 2,00

550

551

552

553

Mean max

(nm)

Hill type Fit

Mean L

SP

Resonance

ma

x (

nm

)

Cysteamine Concentration (mM)

A Bio-responsive hydrogel is obtained by functionalizing

gold nanoparticles within the hydrogel with a

biorecognition element.

LSPR measurements are used to

monitor the functionalization steps.

10




0,0 0,5 1,0 1,5 2,0-0,05

0,00

0,05

0,10

0,15

0,20

0,25

0,30

De

lta

A (

a.u

.)

Cysteamine Concentration (mM)

0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5 4,0-0,025

0,000

0,025

0,050

0,075

0,100

0,125

A

bs. (a

.u.)

Biotin Concentration (mM)

PEGDA700 PEGDA10kDa

PEGDA700 PEGDA10kDa

Outline

• Dual-Sensing of Streptavidin in PEGDA 10kDa as a Proof of Concept

11




LSPR sensing of Streptavidin

12




Streptavidin was incubated in PEGDA/AuNPs nanocomposites in the same conditions to evaluate plasmon decoupling as a function

of the target concentration.

450 475 500 525 550 575 600 625 650 675 700 725 750

0,0

0,2

0,4

0,6

0,8

1,0

Norm

aliz

ed Inte

nsity (

a.u

.)

Wavelength (nm)

Cy3 Exctitation

Cy3 Emission

Bio-Responsive Hydrogel

Fluorescence-Enhancement Evaluation

PEGDA – Streptavidin−cy3™ PEGDA/AuNPs – Streptavidin−cy3™

PEGDA – Background PEGDA/AuNPs – Background

Fluorescent Streptavidin−cy3™ (100 nM) was incubated in

PEGDA hydrogels and PEGDA/AuNPs nanocomposites in

the same conditions to allow the computation of the

Fluorescence Enhancement (FE).

13




3D MEF Biosensor: Streptavidin Sensing

10 100 1000

0

2000

4000

6000

8000

10000

12000

14000

Flu

ore

scence Inte

nsity (

a.u

.)

Streptavidin Concentration (nM)

Fluorescence Intensity

Bio-responsive PEGDA/AuNPs nanocomposites functionalized with Biotin with Streptavidin- cy3™.

Titration Curve

Control Streptavidin [480 nM]

0

2000

4000

6000

8000

10000

12000

14000

Flu

ore

scence Inte

nsity (

a.u

.)

Fluorescence Intensity

Specificity

Test

Streptavidin-

cy3™

Biotin bound

to AuNPs

BSA

Blocking

Streptavidin- cy3™ Interaction

Functionalization

Cysteamine-modified

AuNPs Missed Streptavidin- cy3™ Interaction

Control

BSA

Blocking

Streptavidin-

cy3™

14




Outline

• Conclusions and Future Perspectives

15




Conclusions and Future Perspectives

Evaluation of Fluorescence enhancement by

MEF - dual mechanism in 3D-bioresponsive

hydrogels.

Achievements

To Do List

Work in Progress

▪ Fabrication of nanocomposites embedding differently

shaped nanoparticles (gold nanostars).

Confocal Microscopy

50 nm

Optimization of the functionalization scheme.

Chemical modification of the AuNPs surfaces within the

hydrogel and sensing of the fluorescent streptavidin.

Study of the swelling effect on the

re-arrangement of nanoparticles

within the 3D network.

▪ Combination of the designed 3D bio-

responsive hydrogels with miniaturized

LED and spectrometer as portable

device (POCT).

16




Dr. Luca De Stefano, Research Director

Dr. Principia Dardano, Researcher

Dr. Ilaria Rea, Researcher

Dr. Mario Battisti, Researcher

Dr. Selene De Martino, Researcher

Dr. Rosalba Moretta, Researcher

Chiara Tramontano, PhD Student

Chiara Tammaro, PhD Student

Giovanna Chianese, Research Fellowship

Carlo Forestiere, Associate Professor

Thank you for your

kind attention


Plasmonic hydrogel nanocomposites with combined optical and mechanical

properties for biochemical sensing

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