Biomaterials for Photonics

COURSE: NANOPHOTONICS AND BIOPHOTONICSCODE: NAST 733COURSE INSTRUCTOR: ASSISTANT PROFESSOR DR. P. THANGADURAI.

PRESENTED BY :ROOPAVATH UDAY KIRANM.Tech 2ND YEAR , sem -3.

Overview of the talk

• Introduction• Bioderived materials• Bacteriorhodopsin (BR)• Green Fluorescent Protein (GFP)• DNA as a photonics material• Bioinspired materials• References

Introduction

• The development of photonics technology is crucially dependent on the availability of suitable optical materials.

• Biomaterials with significant optical properties are emerging as an important class of materials for a variety of photonics applications.

Image ref: Paras N. Prasad - Introduction to Biophotonics - Wiley-Interscience (2003)

Materials derived from biological systems are advantageous because:

• Flawless composition• Stereo specific structure• Flexibility• Biodegradable property

Compounds of biological origin can spontaneously organize into complex structures and function as systems possessing long range and hierarchical order.

1. Bioderived materials, naturally occurring or their chemical modifications

2. Bioinspired materials, synthesized based on guiding principles of biological systems

3. Biotemplates for self-assembling of photonic active structures

4. Bacteria bioreactors for producing photonic polymers.

Types of biomaterials for photonics applications

Biomaterials for photonic applications

BIODERIVED MATERIALS

Naturally occurring biological matter or their chemically derivatized forms.

Examples:• Bacteriorhodopsin for holographic memory• Green fluorescent proteins for photosensitization• DNA as host for laser dyes• Biocolloids for photonics crystal media

Bacteriorhodopsin

• Bacteriorhodopsin (often abbreviated as bR) grows in the purple membrane of a salt marsh bacterium known as Halobacterium salinarium or Halobacterium halobium (Birge et al., 1999).

• The BR molecule is a retinal-protein complex, consisting of a protein molecule (BR) and a retinal molecule (oxidized A vitamin form also called Vitamin A aldehyde) bound by a Schiff base.

• The protein has a molecular weight of 26.534 DA, and 248 amino-acid residues in a polypeptide chain.

• The chain has seven alpha helices in dimeric structure, and exists in a globule-shaped 3-D structure

Image from: Bioengineering of Materials, Nikolai Vsevolodov (auth.), David Amiel (eds.)-Biomolecular Electronics An Introduction via Photosensitive Proteins - Birkhauser Boston (1996)

• BR belongs to the class of transmembrane proteins, and penetrates the entire thickness of the membrane contacting both the cytoplasmic and the external surfaces.

• Retinal is linked to the 216th lysine residue located approximately two-thirds the distance from the cytoplasmic surface of the membrane.

• In the dark, retinal occurs in all-trans and 13-cis isomeric configurations.

• In the light, all 13-cis retinals isomerize to the all-trans configuration.

• Experiments with BR mutants confirm the hypothesis about proton translocation across proton-acceptor groups inside the protein.

• The model for this path was proposed by Henderson et al. [1990]. Upon radiation, all trans retinal isomerization and protonation of a Schiff base occur.

• The proton is released via Asp-85 and migrates further towards the external side of the PM represented by M to N or M to BR570 conversion during a photocycle.

• This is one of the most widely accepted models.

• Every radiated BR molecule pumps the average of 100 protons per second across the purple membrane, using up energy an average of 100 quanta.

• We say "average" because, according to some reports, 1 light quantum transports from 0.8 to 1.2 protons [Grzesiek and Dencher 1988].

• We must remember that 1 PM contains 50,000-150,000 BR molecules.

• From an engineers viewpoint, PM is a perfectly reliable structure, which by some accident happened to be of biological origin

Bacteriorhodopsin for holographic memory

The advantage of using stored holograms for memory application is that in the same space (volume element) many different holograms (thousands) canbe recorded by changing the angle of the writing incident beams. This processis called angular multiplexing

Green Fluorescent Protein (GFP)• Green fluorescent protein (GFP) is a naturally

fluorescent protein (MW 27kDa) isolated from the jelly fish Aequorea victoria (Shimomura etal,1962).

• One major advantage of GFP is that it can become fluorescent without requiring any exogenous substrates or enzymes.

• This is because the chromophore of GFP is formed by an internal post-translational autocatalytic cyclization of three amino acids (Chalfie etal.,1994)

• Protein composed of 238 amino acid residues that exhibit bright green fluorescence when exposed to light in the blue to ultra violet range.

• Absorption in two bands at ~395nm and 475nm covers a broad range of UV and visible regions.

• GFP can be used as photosensitizer.

• GFP was chosen as a photosensitizer because of its high fluorescence quantum yield of 80% and excitation covering a major portion of the UV to blue-green wavelengths.

Confocal image of the worm Caenorhabditis elegas. Six luminous spots can be distinguished on the worm, representing the fluorescence yielded from the Green Fluorescent Protein (GFP) molecules

Applications of GFP

• Can be applied in molecular photonic switches or optical storage.

• GFP also exhibits efficient two-photon excitation when excited at 800 nm. Two-photon excitation has successfully been used to produce up-conversion lasing in GFP.

• As molecular Photodiode. GFP exhibits a very efficient photoinduced electron transfer such as those found for photoelectric conversion in retina and long-range electron transfer in photosynthetic organisms.

Applications of the GFP Technology for Biophotonic Studies of Programmed Cell Death

DNA AS A PHOTONIC MATERIAL• The most important and famous biomaterial known to

man is DNA (Deoxyribonucleic Acid), that carries the genetic code in all living organisms.

• DNA molecules are present in either an aqueous or organic-solvent solution and are transported in a fluid under the influence of electric fields or fluid flow.

• In contrast, solid-state devices are based on thin films of DNA. DNA films are produced by solution methods where a reaction between the DNA and a cationic surfactant (such as cetyl trimethyl ammonium — CTMA) produces a DNA–lipid complex that is insoluble in water but soluble in alcohols

An artist’s view of DNA being incorporated into an OLED structure (drawing by W. Li)

• Bioinspired materials are those synthesized on the basis of governing principles of biological systems.

Example: Light harvesting dendrimers

modeled after a naturally occurring photosynthetic system, a chlorophyll assembly

consists of a large array of chlorophyll molecules that surround a reaction centre

chlorophyll array acts as an efficient light harvesting antenna to capture photons from the sun and

transfer the absorbed energy to the reaction centre.

Bioinspired materials

• The reaction centre utilizes this energy to produce charge separation, eventually forming ATP and NADPH.

• Frechet et al. have demonstrated two-photon excited efficient light harvesting in novel dendrite systems.

• Here the antennas are efficient two-photon absorbers that absorb near-IR photons at 800 nm and transfer the excitation energy quantitatively to the core molecule

References

• Paras N. Prasad-Introduction to Biophotonics-Wiley-Interscience (2003).

• Xun Shen, Roel van Wijk-Biophotonics_ Optical Science and Engineering for the 21st Century-Springer (2006).

• Bioengineering of Materials by Nikolai Vsevolodov (auth.), David Amiel (eds.)-Biomolecular Electronics - An Introduction via Photosensitive Proteins - Birkhauser Boston (1996)

• A. J. Steckl; “DNA - a new material for photonics?,” Nat. Photon. 1, 3(2007).

Thank you for your kind attention..!