Limited Penetration Depth Research Articles

An NIR-II-photoresponsive CoSnO3 nanozyme for mild photothermally augmented nanocatalytic cancer therapy.

The main challenges of nanozyme-based tumor catalytic therapy (NCT) lie in the unsatisfactory catalytic activity accompanied by a complex tumor microenvironment (TME). A few nanozymes have been designed to possess both enzyme-like catalytic activities and photothermal properties; however, the previously reported nanozymes mainly utilize the inefficient and unsafe NIR-I laser, which has a low maximum permissible exposure limit and a limited penetration depth. Herein, we report for the first time an all-in-one strategy to realize mild NIR-II photothermally amplified NCT by synthesizing amorphous CoSnO3 nanocubes with efficient triple enzyme-like catalytic activities and photothermal conversion properties. The presence of Co2+ and Sn4+ endows CoSnO3 nanocubes with the triple enzyme-like catalytic activities, not only achieving enhanced reactive oxygen species (ROS) generation through the Co2+-mediated peroxidase-like catalytic reaction to generate ˙OH and Sn4+-mediated depletion of overexpressed GSH, but also realizing the catalytic decomposition of endogenous H2O2 for relieving tumor hypoxia. More importantly, the obtained CoSnO3 nanocubes with a high photothermal conversion efficiency of 82.1% at 1064 nm could achieve mild hyperthermia (43 °C), which further improves the triple enzyme-like catalytic activities of the CoSnO3 nanozyme. The synergetic therapeutic efficacy of the NIR-II-responsive CoSnO3 nanozyme through mild NIR-II PTT-enhanced NCT could realize all-in-one multimodal tumor therapy to completely eliminate tumors without recurrence. This study will open a new avenue to explore NIR-II-photoresponsive nanozymes for efficient tumor therapy.

Tumor oxygenation nanoliposomes promote deep photodynamic therapy for triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is an aggressive type of breast cancer and has many characteristics including high metastatic rates, poor overall survival, and low response to traditional chemotherapy. Photodynamic therapy (PDT), emerging as a precise treatment modality, has shown promise in improving the antitumor response. However, it still faces challenges such as limited light penetration depth, rapid oxygen consumption, and inadequate targeting ability. In this study, we developed Rose Bengal (RB, photosensitizer) and oxygen co-loaded CREKA-modified UCNP-based nanoliposomes (CLIP-RB-PFOB@UCNP) for tumor targeting and near-infrared (NIR)-triggered deep and long-lasting PDT. Our results demonstrated that CLIP-RB-PFOB@UCNP effectively targeted and accumulated in tumor tissue through the interaction between CREKA and fibronectin, which is overexpressed in tumor cells. Under NIR irradiation, CLIP-RB-PFOB@UCNP exhibited significant destruction of orthotopic tumors, reduced the level of HIF-1α, and efficiently suppressed lung metastasis in a metastatic TNBC model. In conclusion, this study offers new avenues for improving the therapeutic outcomes of PDT for clinical TNBC treatment.

Light/X-ray/ultrasound activated delayed photon emission of organic molecular probes for optical imaging: mechanisms, design strategies, and biomedical applications.

Conventional optical imaging, particularly fluorescence imaging, often encounters significant background noise due to tissue autofluorescence under real-time light excitation. To address this issue, a novel optical imaging strategy that captures optical signals after light excitation has been developed. This approach relies on molecular probes designed to store photoenergy and release it gradually as photons, resulting in delayed photon emission that minimizes background noise during signal acquisition. These molecular probes undergo various photophysical processes to facilitate delayed photon emission, including (1) charge separation and recombination, (2) generation, stabilization, and conversion of the triplet excitons, and (3) generation and decomposition of chemical traps. Another challenge in optical imaging is the limited tissue penetration depth of light, which severely restricts the efficiency of energy delivery, leading to a reduced penetration depth for delayed photon emission. In contrast, X-ray and ultrasound serve as deep-tissue energy sources that facilitate the conversion of high-energy photons or mechanical waves into the potential energy of excitons or the chemical energy of intermediates. This review highlights recent advancements in organic molecular probes designed for delayed photon emission using various energy sources. We discuss distinct mechanisms, and molecular design strategies, and offer insights into the future development of organic molecular probes for enhanced delayed photon emission.

Tomographic Magnetic Particle Imaging with a Single-Sided Field-Free Line Scanner.

Magnetic Particle Imaging (MPI) is a biomedical imaging modality that shows promise in enhancing clinical imaging capabilities. While there are current efforts to expand MPI hardware to enable wholebody and head imaging, this comes at a significant cost in terms of complexity and expense. A single-sided scanner can offer greater accessibility to the scanning area, as all hardware is located on one side of the device's surface, however, at the price of the limited penetration depth. Despite this, a single-sided device could serve as an open geometry preclinical scanner and a clinical instrument for local screening and procedures. The original single-sided device was introduced for a field-free point encoding gradient, which may limit its practical characteristics. We developed a field-free line single-sided device that has improved imaging characteristics, which is beneficial for preclinical applications and potential clinical translation. We demonstrated full tomographic imaging capabilities with the prototype of a single-sided MPI scanner and characterized the imaging performance of our imaging system. MPI has the potential to image various human body regions, particularly for breast cancer diagnosis. Our research tackles the crucial aspect of scalability in the emerging MPI technique.

A self-enhanced chemiexcited PDT system for targeted and efficient treatment of deeply seated tumors

NP3 with H2O2 supplementation and self-enhanced chemiexcited PDT system are developed, exhibiting efficient chemiexcited PDT activity towards subcutaneously implanted and lung metastatic tumors, providing new insights for development of novel chemiexcited PDT.

Multimodal optoacoustic imaging: methods and contrast materials.

Optoacoustic (OA) imaging offers powerful capabilities for interrogating biological tissues with rich optical absorption contrast while maintaining high spatial resolution for deep tissue observations. The spectrally distinct absorption of visible and near-infrared photons by endogenous tissue chromophores facilitates extraction of diverse anatomic, functional, molecular, and metabolic information from living tissues across various scales, from organelles and cells to whole organs and organisms. The primarily blood-related contrast and limited penetration depth of OA imaging have fostered the development of multimodal approaches to fully exploit the unique advantages and complementarity of the method. We review the recent hybridization efforts, including multimodal combinations of OA with ultrasound, fluorescence, optical coherence tomography, Raman scattering microscopy and magnetic resonance imaging as well as ionizing methods, such as X-ray computed tomography, single-photon-emission computed tomography and positron emission tomography. Considering that most molecules absorb light across a broad range of the electromagnetic spectrum, the OA interrogations can be extended to a large number of exogenously administered small molecules, particulate agents, and genetically encoded labels. This unique property further makes contrast moieties used in other imaging modalities amenable for OA sensing.

Recent breakthroughs in graphene quantum dot-enhanced sonodynamic and photodynamic therapy.

Water-soluble graphene quantum dots (GQDs) have recently exhibited considerable potential for diverse biomedical applications owing to their exceptional optical and chemical properties. However, the pronounced heterogeneity in the composition, size, and morphology of GQDs poses challenges for a comprehensive understanding of the intricate correlation between their structural attributes and functional properties. This variability also introduces complexities in scaling the production processes and addressing safety considerations. Light and sound have firmly established their role in clinical applications as pivotal energy sources for minimally invasive therapeutic interventions. Given the limited penetration depth of light, photodynamic therapy (PDT) predominantly targets superficial conditions such as dermatological disorders, head and neck malignancies, ocular ailments, and early-stage esophageal cancer. Conversely, ultrasound-based sonodynamic therapy (SDT) capitalizes on its superior ability to propagate and focus ultrasound within biological tissues, enabling a diverse range of therapeutic applications, including the management of gliomas, breast cancer, hematological tumors, and modulation of the blood-brain barrier (BBB). Considering the advancements in theranostic and precision therapies, reevaluating these conventional energy sources and their associated sensitizers is imperative. This review introduces three prevalent treatment modalities that harness light and sound stimuli: PDT, SDT, and a synergistic approach that integrates PDT and SDT. This study delineated the therapeutic dynamics and contemporary designs of sensitizers tailored to these modalities. By exploring the historical context of the field and elucidating the latest design strategies, this review underscores the pivotal role of GQDs in propelling the evolution of PDT and SDT. This aspires to stimulate researchers to develop "multimodal" therapies integrating both light and sound stimuli.

Surface disinfection of wheat kernels using gas phase hydroxyl-radical processes: Effect on germination characteristics, microbial load, and functional properties.

Wheat kernels harbor a diverse microflora that can negatively affect the suitability of the grains for further processing. To reduce surface microflora, a kernel disinfection method is required that does not affect grain functionality. Three different versions of gas phase hydroxyl-radical processes were compared with the common method for grain disinfection, that is, a bleach treatment. The gas phase hydroxyl-radicals are generated by the UV-C mediated degradation of hydrogen peroxide and/or ozone in a near water-free process. It was found that treating kernels with a bleach solution could reduce total aerobic count (TAC) and fungal count to below the level of enumeration. In comparison, the gas phase hydroxyl-radical treatment, that is, H2 O2 -UV-ozone treatment, could support a 1.3 log count reduction (LCR) in TAC and a 1.1 LCR in fungal count. The microbial load reduction for the wholemeal samples was less pronounced as endophytic microorganisms were less affected by all treatments, hinting at a limited penetration depth of the treatments. Despite reducing the microbial load on the kernel surface through the bleach and H2 O2 -UV-ozone treatments, none of these treatments resulted in a reduced microbial count on grains that underwent sprouting after the treatments. No negative effect on germination power or development of the seedling was observed for any of the treatments. The gluten aggregation behavior and xylanase activity of the wholemeal also remained unchanged after the gas phase hydroxyl-radical treatments. Our findings suggest that UV-H2 O2 -ozone treatment shows promise for dry-kernel disinfection, but further optimization of the processing parameters is required.

A biomimetic cuproptosis amplifier for targeted NIR-II fluorescence/photoacoustic imaging-guided synergistic NIR-II photothermal immunotherapy

The therapeutic efficacy of cuproptosis combined with phototheranostics is still hindered by easy copper efflux, nonspecific accumulation and limited light penetration depth. Here, a high-performance NIR-II semiconductor polymer was first synthesized through dual-donor engineering. Then a biomimetic cuproptosis amplifier (PCD@CM) was prepared by Cu(II)-mediated coordinative self-assembly of NIR-II ultrasmall polymer dots and the chemotherapeutic drug DOX, followed by camouflaging of tumor cell membranes. After homologous targeting delivery to tumor cells, overexpressed GSH in the tumor microenvironment (TME) triggers the disassembly of the amplifier and the release of therapeutic components through the reduction of Cu(II) to Cu(I), which enable NIR-II fluorescence/photoacoustic imaging-guided NIR-II photothermal therapy (PTT) and chemotherapy. The released Cu(I) induces the aggregation of lipoylated mitochondrial proteins accompanied by the loss of iron-sulfur proteins, leading to severe proteotoxic stress and eventually cuproptosis. NIR-II PTT and GSH depletion render tumor cells more sensitive to cuproptosis. The amplified cuproptosis sensitization provokes significant immune surveillance, triggering the immunogenic cell death (ICD) to promote cytotoxic T lymphocyte infiltration together with aPD-L1-mediated immune checkpoint blockade. This work proposes a new strategy to develop cuproptosis sensitization systems enhanced by NIR-II phototheranostics with homologous targeting and anti-tumor immune response capabilities.

Deepened Photodynamic Therapy through Skin Optical Clearing Technology in the Visible Light Window.

The trade-off that shorter wavelength light facilitates the efficient generation of reactive oxygen species (ROS) from photosensitizer (PS) while facing the drawback of limited penetration depth through skin tissue restricts the further development of photodynamic therapy (PDT). Here, we address this contradiction and achieve visible-light-tailored deep PDT combined with the skin optical clearing technology. With the help of the prepared skin optical clearing gel, the refractive index inhomogeneity between skin tissue components is greatly attenuated, and the light scattering effect within the skin tissue is remarkably reduced. As a consequence, the transmittance of visible light at 600 nm through in vitro porcine skin and in vivo mouse skin after treatment increases from approximately 10 and 40 to 70 and 70%, respectively. Furthermore, in the tumor cell eradication experiment, the local ROS generation efficiency in the experimental group is several times higher than that in the control group owing to improved visible transmittance, which is thus responsible for the complete eradication of tumor cells, even when shaded by skin tissue. The results suggest that this strategy may serve as a valuable supplement to the current deep PDT strategies.

Structure Engineered High Piezo-Photoelectronic Performance for Boosted Sono-Photodynamic Therapy.

Sono-photodynamic therapy is hindered by the limited tissue penetration depth of the external light source and the quick recombination of electron-hole owing to the random movement of charge carriers. In this study, orthorhombic ZnSnO3 quantum dots (QDs) with piezo-photoelectronic effects are successfully encapsulated in hexagonal upconversion nanoparticles (UCNPs) using a one-pot thermal decomposition method to form an all-in-one watermelon-like structured sono-photosensitizer (ZnSnO3 @UCNPs). The excited near-infrared light has high penetration depth, and the watermelon-like structure allows for full contact between the UCNPs and ZnSnO3 QDs, achieving ultrahigh Förster resonance energy transfer efficiency of up to 80.30%. Upon ultrasonic and near-infrared laser co-activation, the high temperature and pressure generated lead to the deformation of the UCNPs, thereby driving the deformation of all ZnSnO3 QDs inside the UCNPs, forming many small internal electric fields similar to isotropic electric domains. This piezoelectric effect not only increases the internal electric field intensity of the entire material but also prevents random movement and rapid recombination of charge carriers, thereby achieving satisfactory piezocatalytic performance. By combining the photodynamic effect arising from the energy transfer from UCNPs to ZnSnO3 , synergistic efficacy is realized. This study proposes a novel strategy for designing highly efficient sono-photosensitizers through structural design.

Marriage of a Dual-Plasmonic Interface and Optical Microfiber for NIR-II Cancer Theranostics.

The use of light as a powerful tool for disease treatment has introduced a new era in tumor treatment and provided abundant opportunities for light-based tumor theranostics. This work reports a photothermal theranostic fiber integrating cancer detection and therapeutic functions. Its self-heating effect can be tuned at ultralow powers and used for self-heating detection and tumor ablation. The fiber, consisting of a dual-plasmonic nanointerface and an optical microfiber, can be used to distinguish cancer cells from normal cells, quantify cancer cells, perform hyperthermal ablation of cancer cells, and evaluate the ablation efficacy. Its cancer cell ablation rate reaches 89% in a single treatment. In vitro and in vivo studies reveal quick, deep-tissue photonic hyperthermia in the NIR-II window, which can markedly ablate tumors. The marriage of a dual-plasmonic nanointerface and an optical microfiber presents a novel paradigm in photothermal therapy, offering the potential to surmount the challenges posed by limited light penetration depth, nonspecific accumulation in normal tissues, and inadvertent damage in current methods. This work thus provides insight for the exploration of an integrated theranostic platform with simultaneous functions in cancer diagnostics, therapeutics, and postoperative monitoring for future practical applications.

First magnetic particle imaging to assess pulmonary vascular leakage in vivo in the acutely injured and fibrotic lung.

Increased pulmonary vascular permeability is a characteristic feature of lung injury. However, there are no established methods that allow the three-dimensional visualization and quantification of pulmonary vascular permeability in vivo. Evans blue extravasation test and total protein test of bronchoalveolar lavage fluid (BALF) are permeability assays commonly used in research settings. However, they lack the ability to identify the spatial and temporal heterogeneity of endothelial barrier disruption, which is typical in lung injuries. Magnetic resonance (MR) and near-infrared (NIR) imaging have been proposed to image pulmonary permeability, but suffer from limited sensitivity and penetration depth, respectively. In this study, we report the first use of magnetic particle imaging (MPI) to assess pulmonary vascular leakage noninvasively in vivo in mice. A dextran-coated superparamagnetic iron oxide (SPIO), synomag®, was employed as the imaging tracer, and pulmonary SPIO extravasation was imaged and quantified to evaluate the vascular leakage. Animal models of acute lung injury and pulmonary fibrosis (PF) were used to validate the proposed method. MPI sensitively detected the SPIO extravasation in both acutely injured and fibrotic lungs in vivo, which was confirmed by ex vivo imaging and Prussian blue staining. Moreover, 3D MPI illustrated the spatial heterogeneity of vascular leakage, which correlated well with CT findings. Based on the in vivo 3D MPI images, we defined the SPIO extravasation index (SEI) to quantify the vascular leakage. A significant increase in SEI was observed in the injured lungs, in consistent with the results obtained via ex vivo permeability assays. Overall, our results demonstrate that 3D quantitative MPI serves as a useful tool to examine pulmonary vascular integrity in vivo, which shows promise for future clinical translation.

NIR-II excitation self-assembly nanomedicine for targeted NIR-IIa fluorescence imaging-guided cuproptosis-promoted synergistic therapy against triple-negative breast cancer

Owing to easy copper efflux, the deficiency of targeting delivery and limited tissue penetration depth of light, the combination therapy of cuproptosis and phototheranostics remains enormous challenges towards triple-negative breast cancer (TNBC). To overcome these obstacles, a NIR-II excitation multifunctional nanomedicine is prepared by self-assembly of targeting aptamers (AS1411) utilizes metallic copper ions as coordination nodes, followed by coated with ultrasmall NIR-II polymer dots (Pdots) with excellent optical performances, forming a carrier-free hybrid nanosystem. After positive targeting into TNBC through specific recognition of aptamer towards cell surface nucleolin, Pdots loaded in nanomedicine enable NIR-IIa fluorescence/NIR-II photoacoustic imaging-guided NIR-II photothermal therapy (PTT) under NIR-II (1064 nm) light excitation, achieving precise phototheranostics of TNBC tumors. The loaded Cu(II) is reduced to cytotoxic Cu(I) by intracellular glutathione (GSH) and ferredoxin 1 (FDX1), synchronously enabling chemodynamic therapy (CDT) and inducing cuproptosis against TNBC. NIR-II PTT and GSH depletion further enhance therapeutic efficiency of CDT and cuprptosis through cell sensitization. This work provides a new attempt to integrate NIR-II phototheranostics and cuproptosis into a single nanoplatform with targeting capability for synergistic therapy of TNBC.

Design of a novel nanoparticle to use X-ray fluorescence of TiO2 to induce photodynamic effects in the presence of PpIX

BackgroundRadiotherapy and photodynamic therapy are the methods of cancer treatment. Although one limitation of photodynamic therapy (PDT) is the limited penetration depth of light through tissue, using X-rays does not have this restriction. Self-lighting nanoparticles can convert X-rays into UV/visible. This study focuses on a newly designed nanostructure containing mesoporous silica nanoparticles (MSN), titanium dioxide nanoparticles (TiO2, anatase grade), and protoporphyrin IX (PpIX) as a photosensitizer to overcome the limitations of photodynamic therapy. MethodsAfter the synthesis and characterization of Ti-MSN/PpIX@PVP nanostructure, two ROSes (OH* and 1O2) were measured when the nanostructures were irradiated with 100 kV and 6 MV photons. The toxicity of Ti-MSN/PpIX@PVP nanostructure in presence and absence of radiation was investigated on DFW and HT-29 cell lines. The in-vitro experiments were analyzed using the MTT assay and colony count assay. Finally, the effect of light exposure in the presence of Ti-MSN/PpIX@PVP nanostructure on the two cell lines was studied. The in-vitro studies were evaluated using the Synergism Index (Syn) and Dose Enhancement Factor (DEF). ResultsBased on the FESEM (field emission scanning electron Microscopy) images and DLS (dynamic light scattering) measurements, the size of Ti-MSN/PpIX nanostructure was determined as (35.2 nm) and (168.4 nm), respectively. Based on the spectrofluorimetry results, 100 kV photons produced more ROSes than 6 MV photons. The results of MTT assay and colony formation for X-PDT show Syn >1, except for 100 kV photons for HT-29 cell line. The nanostructure also reduced colony formation induced by X-PDT more effectively when irradiated by 100 kV photons on DFW cells. The results obtained from conventional PDT showed that the ED 50 of the HT-29 cell line was 6 times higher than that of the DFW cell line. ConclusionDesigning and synthesizing Ti-MSN/PpIX@PVP nanostructures offer a promising strategy for reducing the current challenges in PDT and for developing and advancing X-PDT as an innovative cancer treatment technique.

Immobilizing graphitic carbon nitride on porous silica via hydrogen bonds for photocatalytic flow synthesis of azoxybenzene

Heterogeneous photocatalysis is an ideal method for eco-friendly synthesis of value-added chemicals. However, due to the limited penetration depth of photons and inefficient utilization of the catalytic active sites, the scalability of heterogeneous photocatalysis is restrained. Combining heterogeneous photocatalysis and flow system is a promising solution to optimize the light absorption and mass transfer; however, an affordable, practical design of the flow system and the immobilization method of the photocatalyst is still missing. Here, we report a flow system for heterogeneous photocatalytic synthesis of azoxybenzene and its derivatives from reductive coupling of nitrobenzene at a gram-scale using anchored graphitic carbon nitride (gCN) on porous silica (gCN-SiO2). The hydrogen bonds formed between the gCN and the tetramethoxysilane (TMOS) precursor during the dehydrative condensation process prevent unwanted leaching of catalyst, enabling photocatalytic flow synthesis of azoxybenzene with high selectivity, efficiency, and durability. Mechanistic studies reveals that the gCN-SiO2 regulates the photocatalytic reduction kinetics of nitrobenzene by facilitating the generation of nitrosobenzene and N-phenylhydroxylamine intermediates while preventing the formation of unwanted 4-phenylazophenol byproducts, resulting in efficient and selective synthesis of azoxybenzene. Our work provides an alternative path towards large scale heterogeneous photocatalysis.

Challenges in the microwave heating of structured carbon adsorbents

Microwave heating is a promising method for achieving energy-efficient electrification of temperature swing adsorption processes. However, to successfully design the adsorbent bed and the regeneration step, it is crucial to analyse the limited penetration depth of microwaves. In this study, we present the first comprehensive investigation of microwave heating applied to large structured activated carbon adsorbents. The experiments were conducted inside a monomode microwave applicator, which consists of a rectangular waveguide operated at a frequency of 915 MHz. monolithic adsorbents of various shapes and sizes (cubic, rectangular cuboid, cylindrical) with dimensions up to 10 cm, were placed inside the cavity and subjected to microwave powers ranging from 10 to 200 W. To maximise microwave absorption by the sample, the geometry and impedance of the cavity were modified. Temperature measurements were taken at different positions within the monoliths to investigate heating homogeneity. The combined influence of reflections and the limited penetration depth results in very different temperature profiles as the size and shape of the monolith vary, even after optimising the cavity. In general, thinner monoliths heat better at the centre, whereas thicker monoliths experience better heating at the point closer to the radiation source. Additionally, these materials were characterized in terms of their dielectric and textural properties and composition, and it was determined that variations in these properties result in significant differences in the heating behavior. The choice of adsorbent bed size and heating time can be adjusted accordingly to maximise energy efficiency and heating homogeneity. Furthermore, the rotation of monoliths within the monomode electromagnetic field to achieve heating homogeneity is examined and a comparison with a multimode device is established.

Nanoscale photocatalytic hydrogen production system mitigates inflammation by harnessing glycolysis waste

During tissue infection, immune cells undergo glycolysis, generating lactate that intensifies inflammation and contributes to the excessive production of reactive oxygen species (ROS) and pro-inflammatory cytokines. TiO2 serves as a photocatalyst capable of splitting water and producing H2 when activated by UV light. The study proposes the clinical application of TiO2 to combat tissue inflammation, building upon the antioxidative properties of H2. To address the limited tissue penetration depth of UV light, a TiO2-based photocatalytic H2 production system is developed, utilizing upconversion nanoparticles (UCNPs) coated with a double-shell structure of SiO2 and TiO2 (UST NPs). The efficiency of the UST NPs relies on the utilization of tissue-penetrating near-infrared (NIR) light, which is converted to UV light by the UCNP core. Additionally, the SiO2@TiO2 double-shell enhances light absorbance efficiency and photocatalytic activity. When exposed to NIR light, the UST NPs have the potential to effectively enhance H2 production by utilizing lactate as a sacrificial agent in inflamed tissues, while also facilitating the photocatalytic water splitting process. Consequently, UST NPs + NIR efficiently deplete accumulated lactate in inflamed tissues, reducing inflammation by utilizing the produced H2 to scavenge ROS and pro-inflammatory cytokines. The study explores the innovative application of TiO2-based materials as a photocatalyst, providing fresh perspectives on enhancing H2 production efficiency through the utilization of UCNPs, NIR light, and glycolysis-generated waste (lactate) in inflammation, and examining its relevance in the medical field.

Advance on fiber optic‐based biosensors for precision medicine: From diagnosis to therapy

AbstractPrecision medicine that takes individual variability into account is a new way to minimize the individual variability for precise diagnosis and to establish the certain strategies of efficient therapy. Due to miniaturization sensing area, remoting detection, and flexible operation of light, fiber optics have been successfully used to develop in vitro, wearable, and implanted biosensors, exhibiting high potential in precision medicine from the diagnosis in vitro to therapy in vivo. When modified with the recognition element, the fiber optic‐based biosensor enables the point of care testing for the detection of disease biomarkers. Meanwhile, the fiber optics packaged in a needle/catheter also monitor the medical Internet of things for the continuous assessment of human health. Moreover, the light from the cladding or leaky mode in the fiber optics excites the strong photothermal effect for therapy. The fiber optic‐based biosensor addressed the drawbacks of plasmonic photothermal therapy that limited penetration depths and non‐selectivity therapy. When integrated with a photothermal agent, the fiber optic‐based biosensors provide in situ information for the diagnosis as well as specifically and efficiently kill the tumor cells in deep tissues. In this review, we summarized the advances of fiber optic‐based biosensors in the diagnosis in vitro and therapy in vivo. The challenges and prospection of the fiber optic‐based biosensor application in precision medicine were also explored in depth.

In Situ Photoacoustic Visualization of Pneumonia Induced by MRSA and Specific Identifying Tumor-Homing Bacteria.

Optical imaging holds great promise for monitoring bacterial infectious processes and drug resistance with high temporal-spatial resolution. Currently, the diagnosis of deep-seated bacterial infections in vivo with fluorescence imaging, including near-infrared (NIR) fluorescence imaging technology, remains a significant challenge due to its limited tissue penetration depth. In this study, we developed a highly specific targeting probe, Cy7-Neo-NO2, by conjugating a bacterial 16S rRNA-targeted moiety, neomycin, with a bacterial nitroreductase (NTR)-activated NIR photoacoustic (PA) scaffold using our previously developed caged photoinduced electron transfer (a-PeT) approach. This conjugation effectively resolved probe aggregation issues in physiological conditions and substantially enhanced its reactivity toward bacterial NTR. Notably, Cy7-Neo-NO2 enabled the first in situ photoacoustic imaging of pneumonia induced by methicillin-resistant Staphylococcus aureus (MRSA), as well as the detection of bacteria within tumors. Furthermore, upon NIR irradiation, Cy7-Neo-NO2 successfully inhibited MRSA growth through a synergistic effect combining photothermal therapy and photodynamic therapy. Our results provided an effective tool for obtaining exceptional PA agents for accurate diagnosis, therapeutic evaluation of deep-seated bacterial infections in vivo, and intratumoral bacteria-specific recognition.