1. Introduction: How Optical Components Have Become the Core Engine of Modern Medicine
From the ubiquitous CT and MRI equipment in hospital corridors to the laser scalpels that precisely cut tissue in operating rooms, and the fluorescence microscopes that track the movement of individual proteins in laboratories—optical components have long permeated every aspect of healthcare. Traditionally, optical components have been perceived as playing a supporting role in “illumination” or “imaging”; however, in this article, optical components will be explored in a new capacity within medicine and biotechnology.
2. The Sensing Function of Optical Components
Limitations and Breakthrough Directions of Traditional Optical Biosensing
Biosensing is the most classic application scenario for optical components in in vitro diagnostics. Its basic principle is not complex: target biomolecules (such as antigens, DNA fragments, and tumor markers) bind to recognition elements on the sensor surface, causing changes in local refractive index, fluorescence intensity, or absorption spectrum, which are then captured by the optical system and converted into quantifiable electrical signals. In recent years, we have faced the impossible triangle of “sensitivity-size-cost.” Enzyme-linked immunosorbent assay (ELISA) requires fluorescent labeling and is time-consuming; while surface plasmon resonance (SPR) devices can achieve label-free detection, they are bulky and expensive, making it difficult to penetrate primary healthcare settings. However, with continuous technological updates and development, we have updated our technology—3D micro-printed worm-shaped whispering-gallery mode (WGM) microlaser sensors and continuous-domain bound-state (BIC) meta-optical elements—overcoming the shortcomings of previous products.
3. Optical Elements: Optical Imaging
3.1 Clinical Value of Miniaturized Imaging
Optical imaging is the most direct medical application scenario, but its traditional forms—desktop microscopes and large endoscope systems—are facing pressure from two sides: on the one hand, the cost of high-end equipment, often exceeding one million yuan, limits its widespread adoption in primary healthcare; on the other hand, its bulky size prevents it from entering deep within living organisms for real-time observation.
Miniaturization is the key to breaking this deadlock. The core idea is to replace traditional objectives with technologies such as MEMS micromirrors, fiber optic bundle transmission, and computational optical coding, compressing the imaging system to the millimeter or even micrometer scale. In in vitro detection, miniaturized optofluidic systems integrate sample processing, optical detection, and signal analysis onto a single chip, promoting the widespread adoption of point-of-care testing (POCT). In in vivo detection, capsule endoscopes and microendoscopic probes can already acquire high-resolution images of the digestive tract and blood vessel walls through natural cavities. However, miniaturization comes at the cost of compromised signal-to-noise ratio and resolution—this is where the value of computational optics and AI algorithms lies: using algorithms to compensate for the physical limitations of hardware, achieving a performance balance of “software compensating for hardware.”
3.2 Fluorescence Navigation
The core contradiction on the operating table is often not “how much to remove,” but “where is the boundary?” The boundary between tumor tissue and normal tissue is blurred; excessive resection damages function, while insufficient resection increases the risk of recurrence. In 2025, the team led by Zhang Fan at Fudan University, in collaboration with Yan Bo’s team, developed a “lanthanide rainbow” fluorescent molecular palette. This palette utilizes a multispectral imaging strategy of “excitation encoding, single emission”—leveraging the unique optical properties of the rare-earth element erbium—to encode different markers at the same emission wavelength using different excitation wavelengths. This avoids the problems of low photon utilization efficiency and inconsistent image fidelity across different channels found in traditional multi-emission strategies. In a mouse model of colorectal cancer, this system achieved simultaneous five-color visualization of the primary tumor lesion, metastatic nodules, blood vessels, and intestinal motility. AI algorithms were used to perform real-time spectral unmixing and anatomical structure rendering during surgery.
4. Role of Optical Components and Optical Therapy Solutions
4.1 The Precision Evolution of Laser Therapy
Laser applications in the therapeutic field have spanned over half a century, but its core technology is evolving from “thermal resection” to “precision control.” The interaction mechanisms between lasers of different wavelengths and biological tissues differ fundamentally: ultraviolet (e.g., 193 nm ArF excimer laser) directly breaks molecular bonds through photochemical effects, used in corneal refractive surgery; near-infrared (e.g., 1064 nm Nd:YAG laser) has greater penetration depth and controllable thermal diffusion, widely used in tumor ablation and vascular coagulation; visible light is more commonly used in photodynamic therapy (PDT) and photobiological modulation (PBM). According to the latest review, laser therapy has covered more than ten specialties, including dermatology, ophthalmology, oncology, and neurology, with clinical evidence for photobiological modulation rapidly accumulating in areas such as diabetic wound healing and neuroprotection in Parkinson’s disease.
Current technological evolution is heading in two directions: first, wavelength customization—matching the optimal wavelength to the optical window of a specific target tissue; second, energy precision—controlling the thermal diffusion range through real-time temperature monitoring and closed-loop feedback to avoid damage to adjacent tissues.
4.2 Optical Components: Optogenetics
Optogenetics represents a paradigm shift in optical therapy from “destruction” to “modulation.” The principle behind optogenetics is to express photosensitive ion channel proteins (such as channelrhodopsin) into specific neurons or cells using gene technology, allowing the cell membrane potential to be precisely controlled by specific wavelengths of light. Traditional near-infrared optogenetic tools suffer from background activation in the dark, resulting in limited signal-to-noise ratio. iLight2 significantly reduces dark-state activity by optimizing the linker peptide length between photosensitive and effector proteins, greatly improving light-dark activation contrast. In a biliverdin reductase knockout mouse model, iLight2 achieved precise gene transcriptional regulation in deep tissues, and its therapeutic potential was validated in a wound healing cell model. The clinical translation of optogenetics still faces fundamental challenges such as gene delivery safety and long-term expression stability, but its promising applications in neurodegenerative diseases, cardiac rhythm regulation, and metabolic diseases are attracting significant research investment.
5. Conclusion
The integration of optical components and biomedicine is undergoing a historic leap from “tool empowerment” to “paradigm reconstruction.” When lasers become small enough to live inside cells, when fiber optic sensors become sensitive enough to detect tumor markers as small as one in a trillion, and when metasurfaces become so thin that a mobile phone camera can be turned into a high-precision microscope—optical technology is no longer just an auxiliary tool for doctors, but is becoming the first principle for decoding life and intervening in diseases.