Editing Biophotonics (section)

==Applications==

Biophotonics is an interdisciplinary field involving the interaction between electromagnetic radiation and biological materials including: tissues, cells, sub-cellular structures, and molecules in living organisms.<ref name=":0">{{Cite book|editor4-first=Alexandros|editor4-last=Serafetinides|editor3-first=Albena|editor3-last=Daskalova|editor2-first=Sanka|editor2-last=Gateva|editor1-first=Tanja|editor1-last=Dreischuh|date=2017-01-05|title=Biophotonics for imaging and cell manipulation: quo vadis?|publisher=International Society for Optics and Photonics|volume=10226|pages=1022613|doi=10.1117/12.2263036|series=19th International Conference and School on Quantum Electronics: Laser Physics and Applications|s2cid=136053006}}</ref>

Recent biophotonics research has created new applications for clinical diagnostics and therapies involving fluids, cells, and tissues. These advances are allowing scientists and physicians opportunities for superior, non-invasive diagnostics for vascular and blood flow, as well as tools for better examination of skin lesions. In addition to new diagnostic tools, the advancements in biophotonics research have provided new photothermal, photodynamic, and tissue therapies.<ref name=":1">{{Cite journal|last=Krafft|first=Christoph|date=2016|title=Modern trends in biophotonics for clinical diagnosis and therapy to solve unmet clinical needs|journal=Journal of Biophotonics |volume=9|issue=11–12|pages=1362–1375|pmid=27943650|doi=10.1002/jbio.201600290|s2cid=28680916 }}</ref>

=== Raman and FT-IR based diagnostics ===
[[Raman spectroscopy|Raman]] and [[Fourier-transform infrared spectroscopy|FTIR]] spectroscopy can be applied in many different ways towards improved diagnostics.<ref>{{Cite journal|title=Cultivation-Free Raman Spectroscopic Investigations of Bacteria|last1=B|first1=Lorenz|last2=C|first2=Wichmann|date=May 2017 |pmid=28188076|last3=S|first3=Stöckel|last4=P|first4=Rösch|last5=J|first5=Popp|journal=Trends in Microbiology|volume=25|issue=5|pages=413–424|doi=10.1016/j.tim.2017.01.002}}</ref><ref>{{Cite journal|title=Application of Vibrational Spectroscopy and Imaging to Point-of-Care Medicine: A Review|last1=S|first1=Pahlow|last2=K|first2=Weber|date=September 2018 |journal=Applied Spectroscopy|pmid=30265133|last3=J|first3=Popp|last4=Br|first4=Wood|last5=K|first5=Kochan|last6=A|first6=Rüther|last7=D|first7=Perez-Guaita|last8=P|first8=Heraud|last9=N|first9=Stone|volume = 72|issue = 1_suppl|pages = 52–84|doi = 10.1177/0003702818791939|pmc = 6524782|bibcode=2018ApSpe..72...52P}}</ref> For example:

# Identifying bacterial and fungal [[infection]]s
# Tissue [[Neoplasm|tumor]] assessment in: [[skin]], [[liver]], [[bone]]s, [[Urinary bladder|bladder]] etc.
# Identifying [[Antimicrobial resistance|antibiotic resistances]]

=== Other applications ===

==== Dermatology ====
By observing the numerous and complex interactions between light and biological materials, the field of biophotonics presents a unique set of diagnostic techniques that medical practitioners can utilize. Biophotonic imaging provides the field of [[dermatology]] with the only non-invasive technique available for diagnosing skin cancers. Traditional diagnostic procedures for skin cancers involve visual assessment and biopsy, but a new [[laser-induced fluorescence]] spectroscopy technique allow dermatologists to compare [[spectrograph]]s of a patient's skin with spectrographs known to correspond with malignant tissue. This provides doctors with earlier diagnosis and treatment options.<ref name=":0" />

"Among optical techniques, an emerging imaging technology based on laser scanning, the [[optical coherence tomography]] or OCT imaging is considered to be a useful tool to differentiate healthy from malignant skin tissue".{{attribution needed|date=June 2020}} The information is immediately accessible and eliminates the need for skin excision.<ref name=":0" /> This also eliminates the need for the skin samples to be processed in a lab which reduces labor costs and processing time.

Furthermore, these optical imaging technologies can be used during traditional surgical procedures to determine the boundaries of lesions to ensure that the entirety of the diseased tissue is removed. This is accomplished by exposing [[nanoparticle]]s that have been dyed with a fluorescing substance to the acceptable light photons.<ref name=":1" /> Nanoparticles that are functionalized with fluorescent dyes and marker proteins will congregate in a chosen tissue type. When the particles are exposed to wavelengths of light that correspond to the fluorescent dye, the unhealthy tissue glows. This allows for the attending surgeon to quickly visually identify boundaries between healthy and unhealthy tissue, resulting in less time on the operating table and higher patient recovery. "Using dielectrophoretic microarray devices, nanoparticles and DNA biomarkers were rapidly isolated and concentrated onto specific microscopic locations where they were easily detected by epifluorescent microscopy".{{attribution needed|date=June 2020|reason=The text should say who said this.}}<ref name=":0" />

==== Optical tweezers ====
[[Optical tweezers]] (or traps) are scientific tools employed to maneuver microscopic particles such as atoms, DNA, bacteria, viruses, and other types of nanoparticles. They use the light's momentum to exert small forces on a sample. This technique allows for the organizing and sorting of cells, the tracking of the movement of bacteria, and the changing of cell structure<ref>{{Cite web|url=https://blocklab.stanford.edu/optical_tweezers.html|title=Block lab - Optical tweezers|website=blocklab.stanford.edu|access-date=2017-12-05}}</ref>

====Laser micro-scalpel====
Laser micro-scalpels are a combination of fluorescence  microscopy and a femtosecond laser "can penetrate up to 250 micrometers into tissue and target single cells in 3-D space."<ref name=":2">{{Cite web|url=https://www.biotechniques.com/news/NEWS-New-laser-microscalpel-to-target-diseased-cells/biotechniques-116068.html|title=BioTechniques - NEWS: New laser microscalpel to target diseased cells|website=biotechniques.com|access-date=2017-12-05|archive-url=https://web.archive.org/web/20171206140119/https://www.biotechniques.com/news/NEWS-New-laser-microscalpel-to-target-diseased-cells/biotechniques-116068.html|archive-date=2017-12-06|url-status=dead}}</ref> The technology, which was patented by researchers at the University of Texas at Austin, means that surgeons can excise diseased or damaged cells without disturbing or damaging healthy surrounding cells in delicate surgeries involving areas such as the eyes and vocal chords.<ref name=":2" />

==== Photoacoustic microscopy (PAM) ====
Photoacoustic microscopy (PAM) is an imaging technology that utilizes both laser technology and ultrasound technology.  This dual imaging modality is far superior at imaging deep tissue and vascular tissues than previous imaging technologies. The improvement in resolution provides higher quality images of deep tissues and vascular systems, allowing non-invasive differentiation of cancerous tissues vs healthy tissue by observing such things as "water content, oxygen saturation level, and hemoglobin concentration".<ref>{{Cite journal|last1=Yao|first1=Junjie|last2=Wang|first2=Lihong V.|date=2014-06-01|title=Sensitivity of photoacoustic microscopy|journal=Photoacoustics|volume=2|issue=2|pages=87–101|doi=10.1016/j.pacs.2014.04.002|pmid=25302158|pmc=4182819|bibcode=2014PhAco...2...87Y }}</ref> Researchers have also been able to use PAM to diagnose endometriosis in rats.<ref name=":1" />
[[File:Light_Penetration.png|thumb|Shows the depth of penetration of light through human skin|alt=]]

==== Low level laser therapy (LLLT) ====
Although [[low-level laser therapy]]'s (LLLT) efficacy is somewhat controversial, the technology can be used  to treat wounds by repairing tissue and preventing tissue death. However, more recent studies indicate that LLLT is more useful for reducing inflammation and assuaging chronic joint pain. In addition, it is believed that LLLT could possibly prove to be useful in the treatment of severe brain injury or trauma, stroke, and degenerative neurological diseases.<ref>{{Cite journal|last1=Chung|first1=Hoon|last2=Dai|first2=Tianhong|last3=Sharma|first3=Sulbha K.|last4=Huang|first4=Ying-Ying|last5=Carroll|first5=James D.|last6=Hamblin|first6=Michael R.|date=February 2012|title=The Nuts and Bolts of Low-level Laser (Light) Therapy|journal=Annals of Biomedical Engineering|volume=40|issue=2|pages=516–533|doi=10.1007/s10439-011-0454-7|issn=0090-6964|pmc=3288797|pmid=22045511}}</ref>

==== Photodynamic therapy (PT) ====
[[Photodynamic therapy]] (PT) uses photosynthesizing chemicals and oxygen to induce a cellular reaction to light. It can be used to kill cancer cells, treat acne, and reduce scarring. PT can also kill bacteria, viruses, and fungi. The technology provides treatment with little to no long-term side effects, is less invasive than surgery and can be repeated more often than radiation. Treatment is limited, however, to surfaces and organs that can be exposed to light, which eliminates deep tissue cancer treatments.<ref>{{Cite web|url=https://www.cancer.org/treatment/treatments-and-side-effects/treatment-types/photodynamic-therapy.html|title=Photodynamic Therapy|website=cancer.org|access-date=2017-12-05}}</ref>

[[File:Nanoparticles_(yellow)_targeting_and_entering_cancer_cells_(blue).png|thumb|Nano particles injected into a tumor to use photothermal therapy|alt=]]

==== Photothermal therapy ====
[[Photothermal therapy]] most commonly uses nanoparticles made of a noble metal to convert light into heat. The nanoparticles are engineered to absorb light in the 700-1000&nbsp;nm range, where the human body is [[transparency and translucency|optically transparent]]. When the particles are hit by light they heat up, disrupting or destroying the surrounding cells via hyperthermia. Because the light used does not interact with tissue directly, photothermal therapy has few long term side effects and it can be used to treat cancers deep within the body.<ref>{{Cite journal|last=Li|first=Jing-Liang|date=July–August 2010|title=Gold-Nanoparticle-Enhanced Cancer Photothermal Therapy|journal=IEEE Journal of Selected Topics in Quantum Electronics |volume=16| issue=4 |pages=989–996 |doi=10.1109/JSTQE.2009.2030340 |hdl=1959.3/74995|bibcode=2010IJSTQ..16..989L|s2cid=27216810|hdl-access=free}}</ref>