Biophotonics as a new application in optical technology: A bibliometric analysis

Biophotonics procures wide practicability in life sciences and medicines. The contribution of biophotonics is well recognized in various Nobel Prizes. Therefore, this paper aims to conduct a bibliometric analysis of biophotonics publications. The scientific database used is the Web of Science database. Harzing's Publish or Perish and VOSviewer are the bibliometric tools used in this analysis.

This study found an increasing trend in the number of publications in recent years as the number of publications peaked at 347 publications in 2020. Most of the documents are articles (3361 publications) and proceeding papers (1632 publications). The top three subject areas are Optics (3206 publications), Engineering (1706 publications) and Radiology, Nuclear Medicine, and Medical Imaging (1346 publications).



The United States has the highest number of publications (2041 publications) and citation impact (38.07 citations per publication; h-index: 125). The top three publication titles are Proceedings of SPIE (920 publications), Journal of Biomedical Optics (599 publications), and Proceedings of the Society of Photo Optical Instrumentation Engineers SPIE (245 publications). The potential areas for future research include to overcome the optical penetration depth issue and to develop publicly available biosensors for the detection of common diseases.

Biophotonics is the scientific application of optics in life sciences. It is a breakthrough in biological, pharmaceutical, environmental and agricultural science, and in the medical area [1]. This field can be traced back to the 1600s when Antonie van Leeuwenhoek created the single-lens microscope to observe bacteria and protozoa [2]. Then, in 1903, Niels Ryberg Finsen won the Nobel Prize for the treatment of lupus vulgaris with concentrated light radiation [3,4]. In 2008, Shimomura, Chalfie and Tsien received the Nobel Prize for the findings of green fluorescent protein which is used as a marker protein to observe cells [5,6]. In 2014, Betzig, Hell and Moerner were also recognized with the Nobel Prize award for their super-resolved fluorescence microscopy [7].


Nakamura, Mukai and Senoh's discovery of gallium nitride blue light emitting diodes, which has also been awarded with the Nobel Prize, has potential applications in phototherapy and photobiomodulation [8–10]. In 2018, a Nobel Prize was partly awarded to Arthur Ashkin for the invention of optical tweezers which can be used to study the DNA in bacteriophage capsids [11–13].

The application of biophotonics in diagnostics and therapeutics has helped patients with early detection and targeted treatments for their infections. Electron microscopy and light microscopy can detect nano-scale particles to elucidate virus morphology. Interferometric light microscopy can also differentiate viruses from other nano-scale particles with higher sensitivity to determine virus concentration [14,15].



Atomic force microscopy-infrared spectroscopy and tip-enhanced Raman spectroscopy also enable the retrieval of the structural characteristics of viruses such as the COVID-19 virus [16–18]. Surface plasmon resonance sensing is also useful to characterize biomolecular interactions by immobilizing the receptors on the sensors [19–21]. Methods such as fluorescence microscopy and vibrational spectroscopy can be used to determine the viral load of a patient. Since biophotonics has many practical uses, this paper performs a bibliometric analysis of the application and practicability of biophotonics throughout the years of research in the Web of Science database.

Bibliometric analysis is the precise exploration of scientific data to unravel the evolution of a research area [22,23]. Bibliometric analysis also sheds light on the prominent topics in the research area [24]. However, the bibliometric analysis application in biophotonics is very new and underdeveloped and has not been carried out in the current literature.



Bibliometric analysis of biophotonics is timely considering the presence of scientific databases such as Web of Science for data extraction and the ease of analysis with bibliometric tools such as Harzing's Publish or Perish and VOSviewer [25–27]. Bibliometric analysis is powerful for its ability to analyse large volume of data and provide impartial insights on the performances of articles, authors, and journals.



There are two parts of bibliometric analysis to study the intellectual structure of a research area, namely performance analysis and thematic analysis. Performance analysis involves three metrics in terms of publication, citation, and both citation and publication [28–30]. Publication metric includes total publications (TP); citation metrics are total citations (TC) and average citations per paper (C/P); citation and publication metrics include citations per cited publication (C/CP), h-index (h), and g-index (g). Thematic analyses examine the co-authorship, co-citation, and co-occurrence of the research area [31].



Hence, this paper conducts a bibliometric analysis of biophotonics using the Web of Science database from 1984 to 2023 as of July 5, 2023. This bibliometric analysis of biophotonics publications began with the first indexed publication on the Web of Science database, which was in 1984. The endpoint was chosen based on the date of extraction on July 5, 2023. The research questions of this bibliometric analysis are as follows.

World Biophotonics Research Awards
Visit: biophotonicsresearch.com
Nominate Now: https://biophotonicsresearch.com/award-nomination/?ecategory=Awards&rcategory=Awardee 

Biomedical Applications of Biophotonics

 Biophotonics is the science of producing and utilizing photons or light to image, identify, and engineer biological materials. It is the integration of four major technologies: biotechnology, lasers, photonics, and nanotechnology. Biomedical applications of biophotonics include light interactions in medicine and biology for the purposes of health care.

Diagnostic biophotonics

Diagnostic biophotonics is used to detect diseases in their initial stages before actual medical symptoms occur in patients. By using optics, diagnostic biophotonics provides several advantages of sensing and imaging at the molecular level and also collects multidimensional data for evaluation. Technologies based on light are generally contact-free with less effect on integrity of living subjects and, consequently, can easily be applied in situ.

• Optical tagging: Proteins, cells, DNA, and tissues are tagged with optical tags and their incandescence or fluorescence is measured; also, according to the pathological or physiological situation the changes are analyzed.
• Visualization of complex structures: Advanced laser technology has enhanced imaging of vasculature retinal structures and other optic nerves to provide precise diagnosis of ocular diseases. By observing the modifications occurring in ocular capillaries, the diagnosis of common vascular disorders is enabled.
• Cellular level diagnosis: Sophisticated optical technologies involving lasers, and photonic and biophotonic applications in medicine provide assistance in observing and identifying cellular biochemistry and their functions, organ integrity, and the characteristics of tissues.
• Optical endoscopes: In medical applications, the combination of optical fibers and endoscopes is used for less invasive imaging and surgery of internal organs. Laser light with high-level intensity is delivered using an optical fiber to an inner region of the body, for instance, to eradicate tumors.

Therapeutic biophotonics

Applications of light include treatment of diseases by altering biological processes. Light is used for modifying the cellular functions photochemically and to remove tissues by photomechanical or photothermal process.

• Thermal contact: In this method, heat is produced by high-energy laser light, which is used to disrupt the tissues and, hence the main impact of laser light is photothermal. The response to laser light of the target tissue depends on the extent of increase in temperature and water content in that specific tissue.
• Bioimaging: This is noninvasive imaging technique that visualizes real-time biological processes. This technique aims at lowering the impact of cellular processes as much as possible. Through bio-imaging, the ion or metabolite levels of molecular processes are quantified. Latest developments in bio-imaging include fluorescence resonance energy transfer and two-photon fluorescence excitation microscopy. Images that are reconstructed in both 2D and 3D have enhanced the effective visualization of disease processes and models.
• Photobiostimulation: The process of activating live cells or organisms by laser radiation is known as biostimulation. Low intensity laser and light emitting diode are broadly used in various aspects by dermatologists, dentists, and surgeons. These laser radiations are low powered and do not generate heat that can disrupt biological tissues. They promote a curing effect by deep penetration into the tissues, enabling progression of the photochemical effect.
• Optical coherence tomography (OCT): This method can offer label-free high resolution optical imaging with higher sampling frequency of intraoperative evaluation. OCT is a fast developing technology with the ability to influence many fields of human biology and clinical medicine. It is analogous to ultrasound in which reflected light is detected instead of sound. It can be used in the functioning of optical biopsies by generating images that are similar to histological sections without any removal or blotting of tissues. OCT is used potentially in the study of various tumors and is also applied as intraoperative surgery in breast cancer.

Applications in the field of research

Research in biophotonics aims at improving the sensing and optical imaging techniques to study the structure and function of cells or tissue at the microscopic and nanoscopic levels.

• Spectroscopy: Spectroscopy deals with the study of relation between emitted energy and matter. An electromagnetic radiation is a spectrum that is emitted or absorbed by a sample. This has been classified into various types such as fluorescence, infrared, ultraviolet, nuclear magnetic resonance, absorption, and mass spectroscopy. Raman spectroscopy is a scattering method based on Raman effect. In Raman scattering, the energy difference produces a molecular vibrational excitation.
• Photomechanics: Photomechanical analyses are based on optics used to study the gradient properties in biological materials. It is also used for examining the relationship between the mechanical stress and strain in the structure of root dentin. Light sensitive particles in polymer solutions or solids will undergo a conversion from light to mechanical energy called photo contraction.
• Fiber optic sensors: This technique deals with remote sensing of physical and chemical specifications. By focusing light into the central part and directing to a sample, analytical information is obtained. The optical signals are reflected back across the same fibers and the intensity is calculated. It is broadly accepted in detecting clinical and biochemical analytes, e.g., metabolites, immunoproteins, enzymes, and serum electrolytes. Sensors that react to these parameters are often called biosensors.
  
  World Biophotonics Research Awards
  Visit: biophotonicsresearch.com
  Nominate Now: https://biophotonicsresearch.com/award-nomination/?ecategory=Awards&rcategory=Awardee 

Biophotonic probes for bio-detection and imaging

 Sensitive detection and imaging in bio-microenvironment is highly desired in biophotonic and biomedical applications. However, conventional photonic materials inevitably show incompatibility and invasiveness to bio-systems. To address this issue, Scientists in China reviewed recent progresses of biophotonic probes, including bio-lasers, biophotonic waveguides, and bio-microlenses, made from biological entities with inherent biocompatibility and minimal invasiveness, with applications for bio-detection and imaging. These biophotonic probes open up entirely new windows for biophotonic researches and biomedical applications.

The rapid development of biophotonics and biomedical sciences makes a high demand on photonic structures that are capable of manipulating light at small scales for sensitive detection of biological signals and precise imaging of cellular structures in bio-microenvironment. Unfortunately, conventional photonic structures based on artificial materials (either inorganic or toxic organic) inevitably show incompatibility and invasiveness when interfacing with biological systems. The design of biophotonic probes from the abundant natural materials, particularly biological entities such as virus, cells and tissues, with the capability of multifunctional light manipulation at target sites can greatly increase the biocompatibility and minimizes the invasiveness to biological microenvironment.

In a new paper published in Light Science & Application, a team of scientists, led by Professor Baojun Li and Professor Hongbao Xin from Institute of Nanophotonics, Jinan University, China, reviewed the intriguing progresses of emerging biophotonic probes made from biological entities, such as virus, bacteria, cells and tissues, for bio-detection and imaging. They systematically reviewed three biophotonic probes with different optical functions, i.e., biological lasers for light generation, cell-based biophotonic waveguides for light transportation, and bio-microlenses for light modulation.

To realize their potential biomedical applications of photonic probes, effective control and modulation of light generation are particularly important in various biochemical environments. In this regard, the unique properties of light emitted by lasers, including high intensity, directionality and monochromatic emission, have rendered lasers one of the most useful tools in biomedical applications. Unlike traditional laser devices, bio-lasers utilize biological entities such as cells, tissues and virus, as part of the cavity and/or gain medium in a biological system. Bio-lasers can be categorized into three types, i.e., cell lasers, tissue lasers and virus lasers. These bio-lasers avoid the biohazards of conventional laser devices. Since their optical output is tightly related to the biological structures and activities of the biological systems, bio-lasers can serve as highly sensitive tools in a range of biomedical applications, including cellular tagging and tracking, diagnostics, intracellular sensing, and novel imaging. For example, whispering gallery modes (WGM) microdisks with slightly different diameters resulted in obviously different lasing output spectra. Intracellular cell lasers realized by incorporating these microdisks into cells enabled tagging and tracking of individual cells from large cell populations at the same time.

In addition to bio-lasers for bio-detection and imaging in biological systems, optical waveguides also play important roles in bio-microenvironments. As the main component for light transportation, optical waveguides can deliver light signals in bio-microenvironments for further real-time analysis, and optical waveguides play irreplaceable role to break the tissue penetration limit of light by transporting light into deep tissues.

 To solve the problem of invasiveness and low-biocompatibility of conventional materials-based optical waveguides, living cells hold huge potential for in situ formation of biophotonic waveguide that are inherently elastic, biocompatible, and biodegradable. The refractive index of biological cell (around 1.38) is slightly higher than that of water (around 1.33), thus allowing light guiding through a chain of cells by total internal reflection at the interface of the cell membrane and the water.

A feasible and noninvasive approach to assemble cell-based biophotonic waveguides is optical trapping. By using laser light launched by a tapered optical fiber, biophotonic waveguides can be formed by assembling a chain of bacteria cells through optical force. Light propagation is allowed through cell chains over tens of microns. In another case, nonlinear optical effects have also been applied for biophotonic waveguides formation based on living cells, including algae and red blood cells (RBCs), achieving stable long-distance propagation of light with low loss in biological environments. These cell-based biophotonic waveguides can be performed as a biophotonic probe for cell imaging and biological microenvironment detection.

For example, biophotonic waveguides formed by RBCs provide a potential detection technique for blood pH sensing and diagnosis of blood related disorders.

World Biophotonics Research Awards
Visit: biophotonicsresearch.com
Nominate Now: https://biophotonicsresearch.com/award-nomination/?ecategory=Awards&rcategory=Awardee 

Octopus-Inspired Micro-LEDs Designed for Cancer Therapy

 DAEJEON, South Korea,— Researchers at KAIST and UNIST developed an implantable, shape-morphing 3D micro-LED device capable of effectively delivering light to deep tissues. The technology, designed for pancreatic cancer treatments, has a flexible, octopus-inspired architecture, allowing it to wrap around the entire pancreatic tumor. The device delivers light to the tumor, despite the tumor’s physiological expansion or contraction, enabling continuous, low-intensity photostimulation that precisely targets cancer cells while preserving normal tissue.

Traditional pancreatic cancer treatments struggle due to the dense tumor microenvironment. This biological barrier surrounds the tumor, severely impeding the infiltration of chemotherapy agents and immune cells.

While photodynamic therapy has offered a promising alternative, existing internal light sources, such as lasers, fail to penetrate deep tissues effectively and pose risks of thermal damage and inflammation to healthy organs.

Within in vivo mouse testing, the developed device successfully demonstrated remarkable therapeutic effectiveness. Within three days, the tumor fibrous tissue was reduced by 64% and the pancreatic tissue successfully reverted to normal tissue, overcoming the limitations of conventional photodynamic therapy.

Professor Tae-Hyuk Kwon from UNIST said, "While phototherapy is effective for selective cancer treatment, conventional technologies have been limited by the challenges of delivering light to deep tissues and developing suitable photosensitizers." According to Kwon, the team now aims to build on the work to expand immune-based therapeutic strategies for intractable cancers.

phototherapy

Phototherapy is a medical treatment that involves the use of light to treat various conditions, particularly those related to the skin or mood disorders. There are different types of phototherapies, each tailored to address specific conditions: UV phototherapy: This form of phototherapy utilizes ultraviolet (UV) light to treat skin conditions such as psoriasis, eczema, vitiligo, and certain types of dermatitis. UV radiation can suppress the immune system and reduce inflammation, leading to...

micro-led

Micro-LED (micro-light-emitting diode) refers to a technology that involves the use of very small light-emitting diodes to create displays and lighting systems. These LEDs are miniature versions of traditional LEDs, typically on the order of micrometers in size. Micro-LED displays offer several advantages over other display technologies, including improved brightness, energy efficiency, and the potential for high resolution. Here are key characteristics and features of micro-LED technology: ...

photodynamic therapy

A medical technology that uses lasers or other light sources in combination with photosensitizing drugs to treat cancerous tumors.


World Biophotonics Research Awards
Visit: biophotonicsresearch.com
Nominate Now: https://biophotonicsresearch.com/award-nomination/?ecategory=Awards&rcategory=Awardee 

3D-Printed Lenses Deliver High Resolution and Customizability at Low Cost

 GLASGOW, Scotland, Jan. 21, 2026 — Using consumer-grade 3D printers, researchers at the University of Strathclyde produced high-quality, low-cost optical lenses for superresolution microscopy. When they compared the performance of the 3D-printed optics with that of commercial lenses, the results were similar.

The ability to 3D-print high-grade optics could make high-resolution microscopy and other optical applications more accessible to individual scientists and scientific organizations. It could also provide an inexpensive way to develop fully customized optical imaging systems for research and industry.

In earlier work, the researchers fabricated a fully 3D-printed microscope using a consumer-grade printer. In their current work, they focused on the design and manufacture of a custom, 3D-printed hexagonal (i.e., honeycomb) lenslet array and the integration of this optic into a small, custom, multifocal structured illumination microscopy system (mSIM) for fluorescence imaging.

To achieve an optical surface as smooth as a commercial lens, the researchers created a silicone mold and cast the 3D-printable lens in ultraviolet- (UV)-curable resin. To minimize undesirable effects from diffraction, they developed a method to reduce the optical scattering caused by the layer-by-layer printing process.

The team compared its 3D-printed, honeycomb array to two commercial lenslet arrays — a high-end array with a 250 µm lenslet diameter, and a budget array with a 1 millimeter (mm) by 1.4 mm lenslet footprint. The researchers benchmarked the imaging performance of these optics by quantifying the beam profile homogeneity and the experimental lateral resolution. They used a custom mSIM setup for the benchmarking process.

Researchers at the University of Strathclyde demonstrated a new method for producing high-quality optical lenses for superresolution microscopy using low-cost, consumer-grade 3D printers. Courtesy of the University of Strathclyde.


World Biophotonics Research Awards
Visit: biophotonicsresearch.com
Nominate Now: https://biophotonicsresearch.com/award-nomination/?ecategory=Awards&rcategory=Awardee 

Bright Spot: The Biophotonics Center Shines Light on the Intersection of Physics, Engineering and Medicine

Tucked away on a service road between the edge of Vanderbilt’s main campus and Vanderbilt University Medical Center sits a brick building so intentionally nondescript, other than its tall façade of darkened glass, that it practically screams “mystery” to casual passersby. The intrigue only deepens as you read the sign outside: “W.M. Keck Free Electron Laser (FEL) Center.”

Despite the foreboding exterior, inside is a state-of-the-art laser laboratory that serves as a kind of hub of cross-disciplinary research at Vanderbilt. Forty faculty members from across the university and VUMC—working on topics ranging from astrophysics to cancer treatments—have an affiliation with what is now known as the Biophotonics Center. Led by Anita Mahadevan-Jansen, the Orrin H. Ingram Professor of Biomedical Engineering and professor of neurological surgery, the center also provides undergraduate and graduate students with hands-on experience at one of the world’s leading optics facilities.

The center’s origins trace back to a U.S. Department of Defense grant from the 1980s exploring the use of lasers to treat combat wounds. Then, as now, the center offered an ideal location for such work, situated midway between physics and engineering research labs on one side and patient rooms at VUMC on the other. Similar government-funded facilities were built around the same time at Stanford, Duke, Harvard, and the University of California–Irvine. However, military funding for the program ended in 2007, and Vanderbilt’s Free Electron Laser center closed a year later as a result.

Then last February, the 5,000-square-foot center officially reopened after an extensive renovation. Ongoing research there covers three main areas: cancer treatment and detection, neurosurgery, and nanotechnology. “The Biophotonics Center is aimed at fundamental research and discovery, as well as improving patient care,” Mahadevan-Jansen says. Current funding for biophotonics research at Vanderbilt totals nearly $25 million.

In this photo essay, Vanderbilt Magazine takes a peek inside the Biophotonics Center and some of the work now being done based on research there.

World Biophotonics Research Awards
Visit: biophotonicsresearch.com
Nominate Now: https://biophotonicsresearch.com/award-nomination/?ecategory=Awards&rcategory=Awardee 

Red light can reduce blood glucose levels

The researchers found that 670 nm red light stimulated energy production within mitochondria, the tiny powerhouses within cells, leading to increased consumption of glucose. In particular, it led to a 27.7% reduction in blood glucose levels following glucose intake, and it reduced maximum glucose spiking by 7.5%.

While the study was conducted in healthy individuals, the non-invasive, non-pharmacological technique has the potential to have an impact on diabetes control after meals, as it can reduce damaging fluctuations of blood glucose in the body that contribute to ageing.

The study also highlights the significant long-term consequences for human health, including the potential dysregulation of blood sugars posed by lengthy exposure to blue light. Given the prominence of LED lighting in modern technology and environments, and the fact that LEDs emit towards the blue end of the spectrum with very little red, the authors suggest that this may be a potential public health issue. The research has been published in the Journal of Biophotonics.

Mitochondria provide energy for vital cellular processes, using oxygen and glucose to produce the energy-rich nucleoside adenosine triphosphate (ATP). Previous research has established that long wavelength light between approximately 650-900 nm (spanning the visible through to the near-infrared range) can increase mitochondrial production of ATP which reduces blood glucose and also improves health/lifespan in animals. 

The authors Dr Michael Powner, Senior Lecturer in Neurobiology in the School of Health and Psychological Sciences at City, and Professor Glen Jeffery, Professor of Neuroscience in the UCL Institute of Ophthalmology, also say that this improvement in ATP production can cause signalling changes that are transmitted throughout the body.

They suggest that it may be mediating the abscopal effect, which refers to the phenomenon in cancer treatment where specific irradiation of a primary tumour can result in shrinkage of secondary tumours located in a different part of the body. Likewise, 670 nm light shone selectively on to the backs of mice in previous studies has been shown to result in improvements in ATP that improve symptoms in both a model of Parkinson’s disease and a model of diabetic retinopathy.

To explore the impact of 670 nm red light on blood glucose, the researchers recruited 30 healthy participants, who were then randomised into two groups: 15 in the 670 nm red light group, and 15 in the placebo (no light) group. They had no known metabolic conditions (such as diabetes) and were not taking medication.

Participants were then asked to do an oral glucose tolerance test (drinking glucose dissolved in water) and record their blood glucose levels every 15 minutes over the next two hours. People who received red light exposure 45 minutes prior to drinking glucose exhibited a reduced peak blood glucose level and reduced total blood glucose during the two hours.

Dr Powner, who was the lead author of the study, said: “It is clear that light affects the way mitochondria function and this impacts our bodies at a cellular and physiological level. Our study has shown that we can use a single, 15-minute exposure to red light to reduce blood sugar levels after eating.

“While this has only been done in healthy individuals in this paper, it has the potential to impact diabetes control going forward, as it could help to reduce potentially damaging glucose spikes in the body after meals.”

Professor Jeffery said: “Sunlight has a balance between red and blue, but we now live in a world where blue light is dominant because although we do not see it, LED lights are dominant in blue and have almost no red in them. This reduces mitochondrial function and ATP production. Hence our internal environments are red-starved. Long-term exposure to blue light is potentially toxic without red. Blue light on its own impacts badly on physiology and can drive disrupted blood sugars that may in the long run contribute to diabetes and undermine health spans.

“Pre-1990, we all had incandescent lighting which was OK because it had the balance of blue and red similar to sunlight, but there is a potential health span time bomb in the change to LEDs in an ageing population. This can partly be corrected by spending more time in sunlight.”


World Biophotonics Research Awards
Visit: biophotonicsresearch.com
Nominate Now: https://biophotonicsresearch.com/award-nomination/?ecategory=Awards&rcategory=Awardee