Biophotonics_Concepts_to_Applications

Body region: knee,

shoulder, abdomen

Surgical

instrument

Optical probe

Viewing

scope

Minor incisions

Fig. 1.3 Example of a minimally invasive surgery procedure with an opticalfiber probe and a
surgical tool

Table 1.1 Example sizes of some biological components and measurement aids

Component Generic size

Molecule Water molecule: 0.29 nm

Glucose: 0.70 nm

Amino acid: 0.80 nm

Virus 30 – 100 nm

Bacteria Typical: 0.2μm in diameter and 2– 8 μm in length

Cells Human red blood cell: 9μm

Eukaryotic cell: 10– 20 μm

Tissue

sample

1mm–1 cm (nominal)

Nanoparticle An example probe consists of an array of 450 nm diameter nanoparticles with

center-to-center spacing of 900 nm

Opticalfiber Used for delivering and collecting light; core sizes can range from 9μmto

several mm

Needle

probe

30-gauge needle used in conjunction with an internal opticalfiber probe;

310 μm outer diameter (nominal)

Table 1.2 Photonics techniques used in biophotonics cover time scales over 18 orders of
magnitude

Technique Generic time and application

Spectroscopy Fluorescent decay processes occur in 10−^15 s

Plasma-induced ablation 100 fs–500 ps exposures for dentistry and ophthalmology

Photoablation 10 – 100 ns treatments in ophthalmology

Thermal irradiation 1 μs–1 min exposures for coagulation and tissue vaporization

Photodynamic therapy 5 – 40 min of light exposure for cancer treatments

Photobiomodulation Minutes to hours for therapeutic or cosmetic effects

1.1 What Is Biophotonics? 5