Fundamentals and developments in fluorescence-guided cancer surgery

Minimized background tumor imaging through self-assembled disulfide dicyanine nanoparticles

Fluorescence imaging holds great potential as a powerful diagnostic tool for tumor cell visualization. However, a significant challenge in fluorescence imaging is the high background signal, which obscures the tumor-specific signal and reduced the signal-to-noise ratio (SNR) of imaging, thereby reducing the accuracy of tumor detection and delineation. In this research, we designed and synthesized an amphiphilic disulfide dicyanine ss-diCy7, which can self-assemble into nanoparticles with uniform dispersion in aqueous environments. The fluorescence intensity of these nanoparticles is significantly reduced by 96% due to aggregation-induced quenching arising from π-π stacking. The nanoparticles exhibit a highly specific response to glutathione (GSH) in vitro, resulting in a substantial enhancement of fluorescence intensity by a 24-fold. The enhancement was also achieved in cell and mouse imaging experiments. In addition, in the mouse tumor model, ss-diCy7 nanoparticles demonstrated superior performance compared to traditional mono-cyanine dyes, offering a reduced background signal and prolonged fluorescence duration. This work is anticipated to contribute to the high-resolution tumor imaging.

Identifying Hepsin as a novel biomarker for human esophageal squamous cell carcinoma (ESCC) and its application in fluorescence imaging

Human Esophageal squamous cell carcinoma (ESCC) represents a type of malignant tumor characterized by a high mortality rate and a generally poor surgical prognosis. The accurate labeling and high-specificity visualization of ESCC cells is extremely importance for its precise diagnosis and effective treatment. Fluorescence molecular imaging has emerged as one of the most critical modalities for cancer detection and therapeutic guidance, owing to its superior sensitivity, cost-effectiveness, portability, real-time imaging, and no damage. In this study, we initially verified that Hepsin, a protease, is highly expressed in ESCC through high-throughput immunocapture (HIC) and Western blot (WB) assays. Subsequently, we designed and synthesized an innovative activatable fluorescent probe, Ac-KQLR Rhodamine 110. It is specifically identified and cleaved by Hepsin, which is over-expressed in ESCC cells. Consequently, the Ac-KQLR Rhodamine 110 could be utilized for the activation fluorescence imaging of ESCC cells, providing a method for their precise visualization. In conclusion, this research highlights that the overexpression of Hepsin serves as a novel biomarker for ESCC. Based on Hepsin's high expression in ESCC, our team has developed a distinctive activation fluorescence imaging strategy that can be employed for the tracking and identification of ESCC. The implementation of this strategy could potentially revolutionize the current methodologies used for monitoring and treating cancer, thereby offering new hope and improved outcomes for patients diagnosed with ESCC.

Engineering Bacterial Secretion Systems for Enhanced Tumor Imaging and Surgical Guidance

Current imaging techniques suffer from a lack of specificity and resolution, leading to inaccurate tumor imaging and limited applicability of targeted contrast agents, as they require cancer-specific development. The need for enhanced contrast through improved tumor-to-background ratio (TBR) and the toxicity from repeated injections due to fading fluorescent signals further complicate the issue. Additionally, challenges in visualizing the entire 3D tumor with surface-stained contrast agents highlight the demand for advanced imaging solutions for more precise surgical guidance. A novel approach is proposed utilizing Streptavidin Associated Salmonella (SAS) as a contrast agent for image-guided surgeries. SAS selectively proliferates in cancerous tissues and secretes streptavidin upon induction, enabling the binding of subsequently injected biotin-conjugated fluorescent dyes. This approach enhances tumor visualization with a TBR of up to 15.3, far surpassing conventional agents (TBR ∼ 2), while enabling prolonged 3-day imaging, deep tumor penetration, and precise invasive margin delineation with a single contrast agent injection. Furthermore, biosafety evaluations confirmed efficient bacterial clearance, absence of systemic toxicity, and stable physiological responses, supporting its potential for safe clinical translation. This innovative method offers substantial improvements over existing fluorescent contrast agents and holds promise for both diagnostic and therapeutic applications in cancer surgery.

Selective detection of copper (II) dynamics in living cells and mice with diverse metabolic dysfunction-associated steatotic liver disease using a turn-on bioluminescent probe

Copper is a vital micronutrient that plays a critical role in regulating ecological balance and human physiology. However, excess of copper can have deleterious effects on human health, potentially causing severe diseases, including genetic disorders, neurodegenerative diseases and cancers. Consequently, the development of sensitive and selective probes for the accurate detection of free copper (II) ions (Cu2 +) is imperative for the early diagnosis of Cu-related diseases. In this study, we have developed a turn-on bioluminescent probe, Luc-Cu, for the detection and imaging of Cu2+in vitro and in vivo. In vitro tests demonstrated that Luc-Cu was capable of selectively detecting Cu2+ with a 0.35 μM limit of detection. Moreover, Luc-Cu was successfully employed for imaging Cu2+ in living cells and tumor-bearing mice. Notably, Luc-Cu has been utilized for the monitoring of Cu2+ variation in the livers of mice across diverse stages of metabolic dysfunction-associated steatotic liver disease (MASLD). The exceptional analytical performance of Luc-Cu suggests its potential as a promising and effective imaging tool for the sensitive diagnosis of Cu2+-related diseases with high sensitivity.

Evaluation of indocyanine green inhalation to detect air leak sites during video-assisted thoracoscopic surgery: a prospective study

BACKGROUND

This study aimed to investigate the feasibility and clinical benefits of indocyanine green (ICG) inhalation for detecting air leak sites during video-assisted thoracoscopic surgery (VATS).

METHODS

Between February 2023 and May 2023, a total of 288 patients underwent VATS were enrolled in this study. Among the population, 72 patients received ICG inhalation test following the traditional submersion sealing test. And 216 patients only underwent the submersion sealing test were matched using 1:3 propensity score matching analysis. The results of ICG inhalation test and the clinical outcomes were compared.

RESULTS

In the ICG group, 48 air leak sites were detected in 25 patients (25/72, 34.7%). The conventional submersion sealing test identified 30 air leak sites, while the ICG inhalation test detected 47 sites. Among these detected air leak sites, 34 sites were repaired by suturing or stapling. The postoperative air leak rate in the ICG group (20.8%) was significantly lower than the control group (37.0%, P = 0.011). ICG inhalation test was a favorable factor for reducing postoperative air leaks (OR: 0.40; 95%CI: 0.20-0.78; P = 0.008).

CONCLUSIONS

The ICG inhalation test facilitates the identification of air leak sites that may have been overlooked in the conventional submersion sealing test. This technique is useful to reduce postoperative air leaks for patients undergoing VATS.

TRIAL REGISTRATION

Chinese Clinical Trial Registry: ChiCTR2300067603 on January 13rd 2023.

A new EGFR and c-Met bispecific NIR-II fluorescent probe for visualising colorectal cancer and metastatic lymph nodes

BACKGROUND

The aim of the study was to increase the specificity and targeting of tumour imaging, targeting molecules that enable the simultaneous recognition and binding of multiple tumour-associated receptors. We constructed a NIR-II fluorescence probe based on a bispecific antibody to epidermal growth factor receptor (EGFR) and cellular mesenchymal-epithelial transition factor (c-Met) for visualising colorectal cancers (CRCs) and metastatic lymph nodes.

METHODS

The expression of EGFR and c-Met in tumour and metastatic lymph node specimens from patients with CRC was examined using immunohistochemistry. The EGFR and c-Met bispecific antibody (Rybrevant) was labelled, and its cell-specific binding ability was assessed using laser confocal microscopy. Subcutaneous CRC and orthotopic tumour models were constructed to evaluate the fluorescence imaging of the probe in vivo. To assess the performance of Rybrevant-IRDye800CW in the differential diagnosis of metastatic lymph nodes, a CRC lymph node metastasis model was constructed using human CRC cells implanted in mouse claw pads. Finally, surgically resected CRC tumours and lymph node specimens were incubated with Rybrevant-IRDye800CW for fluorescence NIR-II imaging to evaluate the efficacy of Rybrevant-IRDye800CW for preclinical visualisation.

FINDINGS

The combined expression rate of EGFR and c-Met in CRC and metastatic lymph nodes was significantly higher than the single-target expression rate. The bispecific probe Rybrevant-IRDye800CW was successfully synthesised, and its fluorescence signal could be extended up to 1600 nm using NIR-II imaging. Cell incubation experiments showed that the fluorescence intensity of Rybrevant-IRDye800CW was strongly correlated with EGFR and c-Met overexpression of the cells. NIR-II in vivo fluorescence imaging showed that double-positively expressing subcutaneous tumours significantly uptook Rybrevant-IRDye800CW after tail vein injection of the probe, which rapidly accumulated within the tumours in about 6 h. In EGFR and or c-Met blockade assays, subcutaneous tumours showed weaker uptake of Rybrevant-IRDye800CW. Similarly, Rybrevant-IRDye800CW was specifically identified in orthotopic CRC and lymph node metastasis models, with all orthotopic tumours showing high tumour-to-background ratios in NIR-II imaging. In a NIR-II preclinical study, Rybrevant-IRDye800CW could specifically identify fresh human CRC and its metastatic lymph node tissue.

INTERPRETATION

This study confirmed the complementary EGFR and c-Met expression in CRC and its metastatic lymph nodes. Compared to single-target probes, EGFR and c-Met dual-specific fluorescent probes identified CRC and its metastatic lymph nodes using NIR-II imaging. Thus, NIR-II-guided R0 surgery was performed to resect the CRC and metastatic lymph nodes.

FUNDINGS

This study was supported by the Beijing Natural Science Foundation (Grant numbers: L222054, 7244517, 4232058, L248026, L232020), National Natural Science Foundation of China (NSFC) (92059207, 92359301, 92259303, 62027901, 81930053, 81227901, U21A20386), CAS Youth Interdisciplinary Team (JCTD-2021-08), and the Fundamental Research Funds for the Central Universities (Grant no. JK2024-2-35-02).

Non-Invasive Diagnosis of Early Colorectal Cancerization via Amplified Sensing of MicroRNA-21 in NIR-II Window

Accurate, sensitive, and in situ visualization of aberrant expression level of low-abundant biomolecules is crucial for early colorectal cancer (CRC) detection ahead of tumor morphology change. However, the clinical used colonoscopy and biopsy methods are invasive and lack of sensitivity at early-stage of cancerization. Here, an amplified sensing strategy is developed in the second near-infrared long-wavelength subregion (NIR-II-L, 1500-1900 nm) by integrating DNAzyme-triggered signal amplification technology and lanthanide-dye hybrid system. In the early-stage of CRC, the overexpressed biomarker microRNA-21 initiates the NIR-II-L luminescence ratiometric signal amplification of the CRCsensor. The high sensitivity with a limit of detection (LOD) of 1.26 pm allows non-invasive visualization of orthotopic colorectal cancerization via rectal administration, which achieves early and accurate in situ diagnosis at 2 weeks ahead of the in vitro histological results. This innovative approach offers a promising tool for early diagnosis and long-term monitoring of carcinogenesis progression, with potential applications in other cancer-related biomarkers.

Signal-to-Noise Ratio Imaging and Real-Time Sharpening of Tumor Boundaries for Image-Guided Cancer Surgery

Fluorescence-guided cancer surgery is of considerable current interest in bioanalytical chemistry, engineering, and medicine, but its clinical utility is still hampered by the diffusive (scattering) nature of human tissues and large variations among different patients. Here, we report a new method based on signal-to-noise (contrast-to-noise) ratio (SNR or CNR) imaging for real-time delineation and sharpening of tumor boundaries during image-guided cancer surgery. In particular, we show that in vivo tumor fluorescence signals (both intensity and standard deviation) are strongly correlated with those of the surrounding tissue of the same tissue type and that this relationship is maintained as a function of time for fluorescent tracers such as indocyanine green. This dynamic relationship permits a precise removal of nonspecific background fluorescence from tumor fluorescence. As a result, single-pixel SNR values have been calculated, mapped, and displayed across a large surgical field at 60 frames per second. Pathological validation studies indicate that these SNR values correspond to statistical confidence levels similar (but not identical) to those of normal distributions. When the tumor fluorescence has an SNR of 3, pathological data show a confidence level of approximately 95% in identifying the true tumor lesions. For clinical relevance, we have also carried out first-in-human clinical studies for both oral and esophageal tumors, achieving tumor margin precisions of 1-2 mm with 87.5% histological accuracy and no false positives.

Molecular-Targeted Fluorescence Lymph Node Imaging Could Play a Clinical Role in the Surgical Setting: A Systematic Review

The lymphatic system plays a crucial role in the spread of solid tumors and is often the first site of metastasis, as cancer cells typically invade nearby lymph nodes (LN) before potentially spreading to other LNs through the lymphatic system and distant organs through the bloodstream [...].

Recent Advances in Aggregation-Induced Emission Bioconjugates

Fluorescence imaging technology is playing increasing roles in modern personalized and precision medicine. Thanks to their excellent photophysical properties, organic luminogens featuring aggregation-induced emission (AIE) characteristics (AIEgens) have attracted considerable attention over the past two decades. Because of their superior biocompatibility, ease of processing and functionalization, excellent water solubility, high responsiveness, and exceptional signal-to-noise ratio (SNR) for biotargets, AIE bioconjugates, formed by covalently linking AIEgens with biomolecules, have emerged as an ideal candidate for bioapplications. In this review, we summarize the progress in preparation, properties, and application of AIE bioconjugates in the last five years. Moreover, the challenges and opportunities of AIE bioconjugates are also briefly discussed.

Preclinical Evaluation of HSP90 Noninvasive Imaging in Colorectal Cancer Diagnosis

Heat shock protein 90 (HSP90) is a powerful molecular chaperone responsible for the stability and integrity of various client proteins, including various transcription factors, kinases, and steroid hormone proteins, among others. Overexpression of HSP90 is closely related to cancer, immune diseases, and neurodegenerative diseases. However, there are few effective fluorescent probes for HSP90. Therefore, we synthesized a near-infrared fluorescent probe YQHSI-MPA-1 targeting HSP90. The probe was later structurally modified to improve the targeting specificity and accuracy in vivo as YQHSI-MPA-2. Furthermore, the application values of YQHSI-MPA-2 in situ CRC, AOM-DSS-induced CRC, and various metastasis models were evaluated. The results showed that YQHSI-MPA-2 had excellent specificity and high tumor contrast. In conclusion, YQHSI-MPA-2 is an ideal tool for tumor detection and surgical navigation.

Fluorescence-guided Surgery for Hepatocellular Carcinoma: From Clinical Practice to Laboratories

Fluorescence navigation is a novel technique for accurately identifying hepatocellular carcinoma (HCC) lesions during hepatectomy, enabling real-time visualization. Indocyanine green-based fluorescence guidance has been commonly used to demarcate HCC lesion boundaries, but it cannot distinguish between benign and malignant liver tumors. This review focused on the clinical applications and limitations of indocyanine green, as well as recent advances in novel fluorescent probes for fluorescence-guided surgery of HCC. It covers traditional fluorescent imaging probes such as enzymes, reactive oxygen species, reactive sulfur species, and pH-sensitive probes, followed by an introduction to aggregation-induced emission probes. Aggregation-induced emission probes exhibit strong fluorescence, low background signals, excellent biocompatibility, and high photostability in the aggregate state, but show no fluorescence in dilute solutions. Design strategies for these probes may offer insights for developing novel fluorescent probes for the real-time identification and navigation of HCC during surgery.

A Near-Infrared Fluorescent Macromolecular Dye for Precise Identification of Glioblastoma Boundaries

Glioblastoma (GBM) is a highly invasive tumor with poorly defined boundaries, often leaving residual tissue after surgery, which contributes to the recurrence and poor prognosis. A critical challenge in GBM treatment is the precise identification of tumor boundaries during surgery to achieve a safe and complete resection. In this study, we present a novel near-infrared fluorescent agent, IR-PEG-cRGD, that is designed to accurately delineate GBM boundaries for surgical navigation of tumor resection. IR-PEG-cRGD is successfully prepared from the cyanine dye IR-820, which is conjugated to poly(ethylene glycol) (PEG) to prolong circulation time and enhance tumor accumulation. Additionally, a glioma-targeting peptide (cRGD, cyclo(Arg-Gly-Asp-d-Phe-Cys)) is conjugated to PEG to selectively target GBM. IR-PEG-cRGD demonstrates effective targeting and enrichment in subcutaneous human-derived GBM mice models, enabling specific distinguishing of the GBM margin from the surrounding parenchyma with a high signal-to-background ratio (SBR) of 4.79. Moreover, IR-PEG-cRGD can pass across the blood-brain barrier (BBB) efficiently. These findings indicate that IR-PEG-cRGD can serve as a valuable tool for the precise intraoperative delineation of GBM boundaries, aiding in safe and complete tumor resection.

Aptamer-Guided, Hydrolysis-Resistant Deoxyoxanosine Enables Epitope- and Moiety-Selective Conjugation to Nonengineered Proteins Even in Complex Environments

In protein engineering, researchers have extensively explored the incorporation of nonprotein entities into proteins to extend their functionalities to various applications; however, achieving precise modifications of proteins is still challenging. This study demonstrates epitope- and moiety-selective conjugation of nonengineered proteins by integrating "slow-reactive and hydrolysis-resistant" deoxyoxanosine (dOxa) into a "target- and epitope-selective" aptamer. The amine-reactive dOxa-containing aptamers are dominantly single-lysine-selective at recognition sites, achieving significantly high conjugation yields with remarkably low off-target reactions in complex environments under near-physiological conditions through a catalyst-free, one-pot reaction. When stoichiometrically controlled protein-DNA conjugates are efficiently produced for various proteins, high conjugation selectivity enables semipermanent regulation of enzymatic functions, targeted labeling in a protein mixture, and even heterofunctionalization of a single protein. As our dOxa-containing aptamers selectively react with the recognition sites of target proteins among nontargets, we demonstrate bioorthogonal labeling of live-cell surface nucleolin and PTK7 in amine-rich cell media, displaying their distinct distributions. Aptamer-guided dOxa positioning offers a promising strategy for site-specific modification of native proteins in complex environments, opening new avenues for the synergistic collaboration between nucleic acids and proteins.

Near-Infrared Chemiluminophore Switches Photodynamic Processes via Protein Complexation for Biomarker-Activatable Cancer Therapy

Despite the potential in cancer therapy, phototheranostic agents often face two challenges: limited diagnostic sensitivity due to tissue autofluorescence and suboptimal therapeutic efficacy due to the Type-II photodynamic process with the heavy oxygen reliance. In contrast, chemiluminescent theranostic agents without the requirement of real-time light excitation can address the issue of tissue autofluorescence, which however have been rarely reported for photodynamic therapy (PDT), not to mention less oxygen-dependent Type-I PDT. In this work, we synthesize near-infrared (NIR) chemiluminophores with the specific binding towards human serum albumin (HSA) to form chemiluminophore-protein complex for cancer detection and photodynamic therapy. Interestingly, after the complexation with HSA, the chemiluminescence (CL) intensities of chemiluminophores are enhanced by over 10-fold; meanwhile, the photodynamic process switches from Type-II (singlet-oxygen-generation dominated) to Type-I (superoxide anion and hydroxyl radical dominated), while the previously reported activated chemiluminophore with non-specific HSA binding can't switch photodynamic process. Based on the optimal chemiluminophore, a nitroreductase-activatable CL probe-protein complex is synthesized, which specially turns on its CL and Type-I PDT in hypoxic tumors for precision therapy. Thus, this study provides a complexation strategy to improve phototheranostic performance of chemiluminophores.

Deep Equilibrium Unfolding Learning for Noise Estimation and Removal in Optical Molecular Imaging

In clinical optical molecular imaging, the need for real-time high frame rates and low excitation doses to ensure patient safety inherently increases susceptibility to detection noise. Faced with the challenge of image degradation caused by severe noise, image denoising is essential for mitigating the trade-off between acquisition cost and image quality. However, prevailing deep learning methods exhibit uncontrollable and suboptimal performance with limited interpretability, primarily due to neglecting underlying physical model and frequency information. In this work, we introduce an end-to-end model-driven Deep Equilibrium Unfolding Mamba (DEQ-UMamba) that integrates proximal gradient descent technique and learnt spatial-frequency characteristics to decouple complex noise structures into statistical distributions, enabling effective noise estimation and suppression in fluorescent images. Moreover, to address the computational limitations of unfolding networks, DEQ-UMamba trains an implicit mapping by directly differentiating the equilibrium point of the convergent solution, thereby ensuring stability and avoiding non-convergent behavior. With each network module aligned to a corresponding operation in the iterative optimization process, the proposed method achieves clear structural interpretability and strong performance. Comprehensive experiments conducted on both clinical and in vivo datasets demonstrate that DEQ-UMamba outperforms current state-of-the-art alternatives while utilizing fewer parameters, facilitating the advancement of cost-effective and high-quality clinical molecular imaging.

Fluorescent Nanobodies for enhanced guidance in digestive tumors and liver metastasis surgery

BACKGROUND

Fluorescence molecular imaging, a potent and non-invasive technique, has become indispensable in medicine for visualizing molecular processes. In surgical oncology, it aids treatment by allowing visualization of tumor cells during fluorescence-guided surgery (FGS). Targeting the urokinase plasminogen activator receptor (uPAR), overexpressed during tissue remodeling and inflammation, holds promise for advancing FGS by specifically highlighting tumors. This study explores the extended use of Nanobody-based (Nb) anti-uPAR tracers, evaluating their receptor binding, ability to visualize and demarcate colorectal (CRC) and gastric cancer (GC), and detect localized (PC) and metastatic (PC-M) pancreatic carcinoma.

METHODS

First, the receptor structure interactions of Nb15, which binds specifically to the human homologue of uPAR, were characterized in vitro to deepen our understanding of these interactions. Subsequently, Nbs 15 and 13-where Nb13 targets the murine uPAR homologue-were labeled with the s775z fluorescent dye and validated in a randomized study in mice (n = 4 per group) using orthotopic human CRC, GC, and PC models, as well as a mouse PC-M model.

RESULTS

Nb15, which binds to the D1 domain of uPAR and competes with urokinase's binding fragment, showed rapid and specific tumor accumulation. It exhibited higher tumor-to-background ratios in CRC (3.35 ± 0.75) and PC (3.41 ± 0.46), and effectively differentiated tumors in GC (mean fluorescence intensity: 0.084 ± 0.017), as compared to control Nbs. Nb13 successfully identified primary tumors and liver metastases in PC-M models.

CONCLUSION

The tested fluorescently-labeled anti-uPAR Nbs show significant preclinical and clinical potential for improving surgical precision and patient outcomes, with Nb15 demonstrating promise for real-time surgical guidance.

Less Is More: Donor Engineering of a Stable Molecular Dye for Bioimaging in the NIR-IIb Window

Fluorescence molecular imaging aims to enhance clarity in the region of interest, particularly in the near-infrared IIb window (NIR-IIb, 1500-1700 nm). To achieve this, we developed a novel small-molecule dye, named DA-5, based on classic cyanine dyes (heptamethine or pentamethine is essential for wavelengths beyond 1000 nm). By reducing excessive polymethine to a single methine and disrupting symmetry to form an asymmetric donor-π-acceptor (D-π-A) architecture, we enhanced the donor's electron-donating capability, yielding emission at 1088 nm. DA-5 exhibits superior properties, including excellent chemo- and photostability, resistance against solvatochromism-caused quenching, and antiaggregation in aqueous solution. With a large Stokes shift (241 nm) and high brightness (321 M-1 cm-1), DA-5 enables high-performance imaging of the lymphatic system, intestinal vessels, whole-body angiography, and cerebral and hindlimb microvasculature in NIR-IIb. This molecular design strategy offers a promising platform for advancing in vivo biophotonics.

Metabolic Acidity/H2O2 Dual-Cascade-Activatable Molecular Imaging Platform Toward Metastatic Breast Tumor Malignancy

Fluorescence imaging in the second near-infrared window (NIR-II) is crucial for accurate tumor diagnosis, offering superior resolution and penetration capabilities. Current NIR-II probes are limited by either being "always on" or responding to one stimulus, leading to low signal-to-noise ratios and potential false positives. We introduced a dual-lock-controlled probe, HN-PBA, activated by both H2O2 and tumor acidic environment. This dual response ensures bright fluorescence at tumor sites, leading to higher tumor-to-normal tissue ratios (T/NT) compared to conventional "always on" probes and probes activated only by H2O2. This strategy allows precise tumor identification and removal of primary and metastatic tumors, achieving superior T/NT ratios (24.3/6.4 for orthotopic and lung metastasis, respectively). Our probe also effectively detected lung metastatic foci as small as≤0.7 mm and showed the capability for accurate lesion localization in clinical breast cancer specimens. This dual-stimuli-responsive strategy could aid future diagnostic probe design.

Tumor agnostic ultrasmall nanoprobes for fluorescence-guided surgical resection in peritoneal metastasis

PURPOSE

Surgical excision of metastases is the only curative treatment strategy in peritoneal carcinomatosis management, and the completeness of tumor resection determines the success of the surgery. Tumor-specific fluorescence-guided probes can improve the outcomes of cytoreductive surgery and thereby prognosis. This study aimed to develop and evaluate the feasibility of fluorescently labeled ultrasmall porous silica nanoparticles (UPSN) for image-guided resection of peritoneally disseminated tumors of different origins.

METHODS

Ultrasmall fluorescent nanoprobes were synthesized and characterized for their physicochemical properties and stability. Tumor-specific uptake and biodistribution profiles were evaluated in syngeneic CT26 colorectal and KPC-689 pancreatic cancer murine models. The practicability of real-time optical UPSN-guided resection was examined in the CT26 colorectal cancer model using a surgical stereomicroscope. Quantitative measurements of tumor sensitivity and specificity were performed. Histopathological examination validated in vivo findings about tumor-specific accumulation and safety of ultrasmall fluorescent probes.

RESULTS

As-synthesized UPSNs were successfully surface modified with Cy5 or Cy3 dyes maintaining sub-15 nm size and near neutral charge which is beneficial for optimized in vivo pharmacokinetics. UPSN-Cy5 demonstrated high tumor-specific uptake and favorable biodistribution profiles in peritoneal metastasis models of CT26 and KPC tumors. Dye-conjugated UPSN enabled resection of microscopic lesions and achieved a higher tumor-to-background ratios in comparison to FDA-approved indocyanine green (ICG) dye in both models. Microscopic evaluation showed tumor localization and off-target safety profile of the UPSN-Cy5.

CONCLUSION

Ultrasmall fluorescent probes were effective in surgical resection of peritoneal metastases with high sensitivity and specificity, thus emerging as promising tumor agnostic agents for image-guided cancer surgery.

APE1-Activated and NIR-II Photothermal-Enhanced Chemodynamic Therapy Guided by Amplified Fluorescence Imaging

The development of intelligent nanotheranostic technology that integrates diagnostic and therapeutic functions holds great promise for personalized nanomedicine. However, most of the nanotheranostic agents exhibit "always-on" properties and do not involve an amplification step, which may largely limit imaging contrast and restrict therapeutic efficacy. Herein, we construct a novel nanotheranostic platform (Hemin/DHPs/PDA@CuS nanocomposite) by assembling DNA hairpin probes (DHPs) and hemin on the surface of PDA@CuS nanosheets that enables amplified fluorescence imaging and activatable chemodynamic therapy (CDT) of tumors. The cancer-relevant APE1 triggers nucleic acid amplification with DHPs to generate activatable and amplified fluorescence signals for discriminating cancer cells from normal cells. Meanwhile, excessive G-quadruplex/hemin-based DNAzyme are also activated, and they function as Fenton-like catalysts to catalyze the production of highly toxic hydroxyl radicals (•OH) for CDT. Moreover, owing to the excellent photothermal conversion efficiency in the near-infrared-II (NIR-II) window, the PDA@CuS not only improves the catalytic performance of CDT but also furnishes PTT. A remarkable antitumor therapeutic effect is demonstrated both in vitro and in vivo. Therefore, the Hemin/DHPs/PDA@CuS nanocomposite is expected to provide a promising avenue for precise imaging-guided antitumor therapy.

Fluorescence-Guided Surgery to Detect Microscopic Disease in Ovarian Cancer: A Systematic Review with Meta-Analysis

Background: The objective in epithelial ovarian cancer is to reach maximal cytoreduction with no visible residual tumor. Tumor detection during cytoreductive surgery depends on visual inspection, palpation, or blind biopsy, methods that lack reliability for identifying microscopic disease. Although the importance of microscopic disease in epithelial ovarian cancer is controversial, it may harbor chemoresistant cells and explain the high recurrence rates. Fluorescence-guided surgery (FGS) is an emerging approach. However, the potential in ovarian cancer remains underexplored; the majority of the existing evidence pertains to gastrointestinal tumors and a limited group of ovarian cancer patients. Their comparative effectiveness is still uncertain. Objective: To systematically review and evaluate the role of fluorescence-guided surgical techniques in detecting microscopic disease in ovarian cancer and compare their efficacy to total peritonectomy. Data Sources: A systematic search was made in three databases (PubMed, Web of Science, and Embase). The search was conducted from 1975 to 2024, including randomized controlled trials, observational studies, and conference abstracts in the last 25 years. Study Selection: Clinical studies published in English involving ovarian cancer patients undergoing FGS or total peritonectomy were included. Case reports, reviews, animal studies, and studies involving mixed cancer populations without ovarian cancer-specific data were excluded. Two independent reviewers screened 631 studies, yielding 12 eligible studies for final analysis. Data Extraction and Synthesis: Data were extracted and synthesized in accordance with PRISMA and MOOSE guidelines, using random-effects models for independent analysis. Sensitivity, specificity, positive predictive value (PPV), and odds ratios (ORs) were grouped, accompanied by subgroup analyses based on the fluorescence agent employed. For quality assessment, we utilized the NIH quality tool. Main Outcome(s) and Measure(s): The primary outcome was the rate of change in surgical management due to fluorescence guidance or total peritonectomy. Secondary outcomes comprised lesion-level sensitivity, specificity, and PPV. Safety outcomes included adverse events associated with fluorescence agents. Results: There were 12 studies involving 429 ovarian cancer patients. FGS improved the detection of microscopic disease compared to standard visualization methods, with a pooled sensitivity of 0.77. Folate receptor-targeted agents had high sensitivity (84%) but low specificity (26%). Aminolevulinic acid (5-ALA) showed superior diagnostic accuracy with a sensitivity of 84% and a specificity of 96%. Total peritonectomy showed no significant advantage over FGS for detecting microscopic disease. The adverse events were mild, with no serious events reported. We observed a high heterogeneity across studies and methodologies. Conclusions and Relevance: Fluorescence-guided surgery utilizing fluorescence tracers demonstrates potential in improving the detection of microscopic disease and may change surgical management in epithelial ovarian cancer, particularly with 5-ALA. Variability in performance and limited data on survival outcomes necessitates additional research. Total peritonectomy does not offer further advantage in the detection of microscopic disease. Future trials should focus on standardizing methodology and evaluating the effects of microscopic disease removal on survival outcomes. Registration: The study was registered to PROSPERO as CRD42024578274.

Diagnostic Value of Gastrin-Releasing Peptide Receptor-Targeted PET Imaging in Oncology: A Systematic Review

Gastrin-releasing peptide receptor (GRPR), overexpressed in various cancers, is a promising target for positron emission tomography (PET). This systematic review investigated the diagnostic value of GRPR-targeted PET imaging in oncology. A systematic search was conducted on major medical databases until May 23, 2024. Keywords were modified to include clinical original studies on GRPR-targeted PET in cancer patients. Out of 1624 searched studies initially, 107 were eligible for the full-text review. Overall, data from 38 studies met inclusion criteria, investigating GRPR-targeting radiotracers in breast cancer, prostate cancer, gastrointestinal stromal tumours (GIST) and gliomas (including optic pathway glioma and glioblastoma multiforme). In breast cancer, GRPR-targeted PET effectively detected primary tumours and metastases, particularly in estrogen receptor (ER)-positive patients, and predicted treatment response. In prostate cancer, high sensitivity (up to 88%) and specificity (up to 90%) for detecting primary tumours were observed, providing added value when combined with magnetic resonance imaging (MRI). In biochemical recurrence, sites of prostate cancer were identified even at PSA levels below 0.5ng/dL. Compared with PSMA PET, GRPR-targeted PET showed comparable or superior detection rates. Considering GIST, GRPR-targeted PET imaging proved to be a valuable diagnostic tool, particularly when [18F] FDG PET results were inconclusive. Regarding gliomas, GRPR-targeted PET achieved a 100% detection rate (MRI reference), aiding localization, preoperative planning, and differentiation between recurrence and malignant transformation. GRPR-targeted PET shows promise in improving cancer diagnostics, particularly in ER-positive breast cancer, prostate cancer, and gliomas, and may enhance clinical decision-making.

Highly Photoreactive Semiconducting Polymers with Cascade Intramolecular Singlet Oxygen and Energy Transfer for Cancer-Specific Afterglow Theranostics

Afterglow luminescence provides ultrasensitive optical detection by minimizing tissue autofluorescence and increasing the signal-to-noise ratio. However, due to the lack of suitable unimolecular afterglow scaffolds, current afterglow agents are nanocomposites containing multiple components with limited afterglow performance and have rarely been applied for cancer theranostics. Herein, we report the synthesis of a series of oxathiine-containing donor-acceptor block semiconducting polymers (PDCDs) and the observation of their high photoreactivity and strong near-infrared (NIR) afterglow luminescence. We reveal that PDCDs absorb NIR light to undergo a photodynamic process to generate singlet oxygen (1O2), which intramolecularly transfers to and efficiently reacts with the oxathiine block to form the afterglow oxathiine intermediates due to the low Gibbs free energy changes required for this photoreaction. Following intramolecular afterglow energy transfer from the oxathiine donor block to the acceptor block, NIR afterglow emission is produced from PDCDs. Owing to the efficient cascade intramolecular photochemical process, PDCD-based nanoparticles achieve a higher brightness and longer NIR emission compared to most reported afterglow agents, even after ultrashort photoirradiation for only 3 s. Furthermore, the cascade photochemical process within PDCD can be inhibited after bioconjugation with a quencher-linked peptide. This allows the construction of a cancer-activatable afterglow theranostic probe (CATP) that only switches on the afterglow signal and photodynamic function in the presence of a cancer-overexpressed enzyme. Thereby, CATP represents the first afterglow phototheranostic probe that permits cancer-specific detection and photodynamic cancer therapy under preclinical settings. In summary, this study provides a molecular guideline to develop afterglow probes from photoreactive polymers.

Ultrabright contrast agents with synergistic Raman enhancements for precise intraoperative imaging and photothermal ablation of orthotopic tumor models

BACKGROUND

Intraoperative imaging is critical for achieving precise cancer resection. Among available techniques, Raman spectral imaging emerges as a promising modality due to its high spatial resolution and signal stability. However, its clinical application for in vivo imaging is limited by the inherently weak Raman scattering signal. To address this challenge, we developed a novel strategy that integrates two enhancement mechanisms into a single Raman contrast agent.

RESULTS

This contrast agent exploits the synergistic effects of an anisotropic gold nanorod and a polypyrrole-polydopamine hybrid, resulting in a substantial amplification of Raman signals. Consequently, the agent enables clear delineation of malignant tissues in both orthotopic and subcutaneous tumor models. Beyond its imaging capability, the agent also facilitates photothermal ablation, providing a long-term solution for suppressing tumor recurrence.

CONCLUSION

This study systematically evaluates the imaging performance of the synthesized Raman contrast agents across different tumor models and highlights the critical role of optimizing the aspect ratio of anisotropic agents for in vivo imaging. By offering a dual-function Raman contrast agent, this research advances the potential of Raman spectral imaging for intraoperative applications and clinical translation.

Recent Advances in Indocyanine Green-Based Probes for Second Near-Infrared Fluorescence Imaging and Therapy

Fluorescence imaging, a highly sensitive molecular imaging modality, is being increasingly integrated into clinical practice. Imaging within the second near-infrared biological window (NIR-II; 1,000 to 1,700 nm), also referred to as shortwave infrared, has received substantial attention because of its markedly reduced autofluorescence, deeper tissue penetration, and enhanced spatiotemporal resolution as compared to traditional near-infrared (NIR) imaging. Indocyanine green (ICG), a US Food and Drug Administration-approved NIR fluorophore, has long been used in clinical applications, including blood vessel angiography, vascular perfusion monitoring, and tumor detection. Recent advancements in NIR-II imaging technology have revitalized interest in ICG, revealing its extended tail fluorescence beyond 1,000 nm and reaffirming its potential as a clinically translatable NIR-II fluorophore for in vivo imaging and theranostic applications for diagnosing various diseases. This review emphasizes the notable advances in the use of ICG and its derivatives for NIR-II imaging and image-guided therapy from both fundamental and clinical perspectives. We also provide a concise conclusion and discuss the challenges and future opportunities with NIR-II imaging using clinically approved fluorophores.

Systematic comparison of fluorescence imaging in the near-infrared and shortwave-infrared spectral range using clinical tumor samples containing cetuximab-IRDye800CW

Significance

Shortwave-infrared (SWIR) imaging is reported to yield better contrast in fluorescence-guided surgery than near-infrared (NIR) imaging, due to a reduction in scattering. This benefit of SWIR was shown in animal studies, however not yet in clinical studies with patient samples.

Aim

We investigate the potential benefit of SWIR to NIR imaging in clinical samples containing cetuximab-IRDye800CW in fluorescence-guided surgery.

Approach

The potential of the epidermal growth factor-targeted NIR dye cetuximab-IRDye800CW in the shortwave range was examined by recording the absorption and emission spectrum. An ex vivo comparison of NIR and SWIR images using clinical tumor samples of patients with penile squamous cell carcinoma (PSCC) and head and neck squamous cell carcinoma (HNSCC) containing cetuximab-IRDye800CW was performed. The comparison was based on the tumor-to-background ratio and an adapted contrast-to-noise ratio (aCNR) using the standard of care pathology tissue assessment as the golden standard.

Results

Based on the emission spectrum, cetuximab-IRDye800CW can be detected in the SWIR range. In clinical PSCC samples, overall SWIR imaging was found to perform similarly to NIR imaging (NIR imaging is better than SWIR in the 2/7 criteria examined, and SWIR is better than NIR in the 3/7 criteria). However, when inspecting HNSCC data, NIR is better than SWIR in nearly all (5/7) examined criteria. This difference seems to originate from background autofluorescence overwhelming the off-peak SWIR fluorescence signal in HNSCC tissue.

Conclusion

SWIR imaging using the targeted tracer cetuximab-IRDye800CW currently does not provide additional benefit over NIR imaging in ex vivo clinical samples. Background fluorescence in the SWIR region, resulting in a higher background signal, limits SWIR imaging in HNSCC samples. However, SWIR shows potential in increasing the contrast of tumor borders in PSCC samples, as shown by a higher aCNR over a line.

Advances and challenges in precision imaging

Technological innovations in genomics and related fields have facilitated large sequencing efforts, supported new biological discoveries in cancer, and spawned an era of liquid biopsy biomarkers. Despite these advances, precision oncology has practical constraints, partly related to cancer's biological diversity and spatial and temporal complexity. Advanced imaging technologies are being developed to address some of the current limitations in early detection, treatment selection and planning, drug delivery, and therapeutic response, as well as difficulties posed by drug resistance, drug toxicity, disease monitoring, and metastatic evolution. We discuss key areas of advanced imaging for improving cancer outcomes and survival. Finally, we discuss practical challenges to the broader adoption of precision imaging in the clinic and the need for a robust translational infrastructure.

Spatiotemporal Mapping of Lymphatic Metastases in Gastric Cancer Using Tumor-Trackable and Enzyme-Activatable Near-Infrared Fluorescent Nanoprobes

Sentinel lymph node biopsy holds significant importance in cancer management, yet the challenge persists in early detection and precise resection of metastasis lymph nodes (LNs) due to the absence of specific and sensitive optical probes. This study reports metastatic LN reporters (MLRs) with an activatable optical output for accurate spatiotemporal mapping of lymphatic metastases in gastric cancer. MLRs are self-assembled entities incorporating mixed amphiphiles with a lipophilic tail and a tumor-targeting ligand or a fluorescent moiety that is caged with a switch cleavable by tumor-specific β-galactosidase (β-Gal). After draining into LNs, MLRs selectively activate their near-infrared fluorescence in the presence of spreading tumor cells. In orthotopic gastric cancer mouse models, the representative reporter MLR1 distinguishes macro/micrometastatic LNs from benign LNs and enables early detection of skip LNs metastasis patterns in a spatial-dependent manner. Such an active sensing mechanism provides a high level of sensitivity and specificity comparable to those of flow cytometry analysis. In surgically resected patient specimens, MLR1 differentiates cancerous tissues and metastatic LNs from normal tissues and benign LNs within 1 h. This study thus presents NIRF nanoprobes that permit facile detection of LN metastases in GC patient samples and highlights a generic translatable nanoprobe design for understanding metastatic progression.

Indocyanine green and near-infrared fluorescence-guided surgery for gastric cancer: a narrative review

In recent years, indocyanine green (ICG) and near-infrared (NIR) fluorescence-guided surgery has become a versatile and well-researched tool for gastric cancer treatment. Our narrative review aims to explore the applications, benefits, and challenges that are associated with this technique. Initially used to detect sentinel lymph nodes in early gastric cancer, its scope has broadened to include several clinical applications. Its most notable advantages are the ability to guide standard lymphadenectomy, intraoperatively localize tumors and define tumor margins. Despite these advantages, there are still ongoing discussions regarding its accuracy, lack of standardized administration, and oncologic safety in sentinel node navigation surgery. The limited tumor specificity of ICG has been especially put into question, hindering its ability to accurately differentiate between malignant and healthy tissue. With ongoing innovations and its integration into newer endoscopic and robotic systems, ICG-NIR fluorescence imaging shows promise in becoming a standard tool in the surgical treatment of gastric cancer.

Immunohistochemical Evaluation of Cathepsin B, L, and S Expression in Breast Cancer Patients

PURPOSE

Cysteine cathepsins are proteases that play a role in normal cellular physiology and neoplastic transformation. Elevated expression and enzymatic activity of cathepsins in breast cancer (BCa) indicates their potential as a target for tumor imaging. In particular cathepsin B (CTSB), L (CTSL), and S (CTSS) are used as targets for near-infrared (NIR) fluorescence imaging (FI), a technique that allows real-time intraoperative tumor visualization and resection margin assessment. Therefore, this immunohistochemical study explores CTSB, CTSL, and CTSS expression levels in a large breast cancer patient cohort, to investigate in which BCa patients the use of cathepsin-targeted NIR FI may have added value.

PROCEDURES

Protein expression was analyzed in tumor tissue microarrays (TMA) of BCa patients using immunohistochemistry and quantified as a total immunostaining score (TIS), ranging from 0-12. In total, the tissues of 557 BCa patients were included in the TMA.

RESULTS

CTSB, CTSL, and CTSS were successfully scored in respectively 340, 373 and 252 tumors. All tumors showed CTSB, CTSL, and/or CTSS expression to some extent (TIS > 0). CTSB, CTSL, and CTSS expression was scored as high (TIS > 6) in respectively 28%, 80%, and 18% of tumors. In 89% of the tumors scored for all three cathepsins, the expression level of one or more of these proteases was scored as high (TIS > 6). Tumors showed significantly higher cathepsin expression levels with advancing Bloom-Richardson grade (p < 0.05). Cathepsin expression was highest in estrogen receptor (ER)-negative, human epidermal growth factor receptor 2(HER2)-positive and triple-negative (TN) tumors. There was no significant difference in cathepsin expression between tumors that were treated with neoadjuvant systemic therapy and tumors that were not.

CONCLUSIONS

The expression of at least one of the cysteine cathepsins B, L and S in all breast tumor tissues tested suggests that cathepsin-activatable imaging agents with broad reactivity for these three proteases will likely be effective in the vast majority of breast cancer patients, regardless of molecular subtype and treatment status. Patients with high grade ER-negative, HER2-positive, or TN tumors might show higher imaging signals.

Divergent Syntheses of Near-Infrared Light-Activated Molecular Jackhammers for Cancer Cell Eradication

Aminocyanines incorporating Cy7 and Cy7.5 moieties function as molecular jackhammers (MJH) through vibronic-driven action (VDA). This mechanism, which couples molecular vibrational and electronic modes, results in picosecond-scale concerted stretching of the entire molecule. When cell-associated and activated by near-infrared light, MJH mechanically disrupts cell membranes, causing rapid necrotic cell death. Unlike photodynamic and photothermal therapies, the ultrafast vibrational action of MJH is unhindered by high concentrations of reactive oxygen species scavengers and induces only a minimal temperature increase. Here, the efficient synthesis of a library of MJH is described using a practical approach to access a key intermediate and facilitating the preparation of various Cy7 and Cy7.5 MJH with diverse side chains in moderate to high yields. Photophysical characterization reveals that structural modifications significantly affect molar extinction coefficients and quantum yields while maintaining desirable absorption and emission wavelengths. The most promising compounds, featuring dimethylaminoethyl and dimethylcarbamoyl substitutions, demonstrate up to sevenfold improvement in phototherapeutic index compared to Cy7.5 amine across multiple cancer cell lines. This synthetic strategy provides a valuable platform for developing potent, light-activated therapeutic agents for cancer treatment, with potentially broad applicability across various cancer types.

A protein structure-dependent fluorescent probe for hemoglobin monitoring and controllable imaging in living cells

A novel protein structure-dependent non-covalent fluorescent probe, DDBM, was developed. It exhibited selective fluorescence "turn-off" responsiveness to bovine hemoglobin (BHb). This responsiveness depended on the interaction between the probe and BHb, with the methoxynaphthalene group significantly contributing to the sensitivity. Non-covalent interactions played a crucial role in stabilizing the binding of DDBM with BHb. DDBM demonstrated a robust anti-interference capability in its BHb responsiveness. Interestingly, the BHb responsiveness of DDBM could be modulated by ibuprofen. Additionally, DDBM exhibited favorable fluorescence enhancement sensitivity to bovine serum albumin (BSA), coupled with a robust anti-interference capability. These distinctive properties of DDBM enabled it to dynamically trace the metabolism of hemoglobin (Hb) and further achieve Hb-mediated precise controllable live cell imaging.

Tumour Marker Expression in Head and Neck Malignancies to Identify Potential Targets for Intraoperative Molecular Near-Infrared Imaging

BACKGROUND

Oral and laryngeal squamous cell carcinoma (OSCC and LSCC) and papillary thyroid carcinoma (PTC) are common head and neck cancers (HNCs) typically treated surgically. Challenges in tumour delineation often lead to inadequate resection margins in OSCC and LSCC, and missed multifocality in PTC. Fluorescence imaging (FLI) using near-infrared tumour-targeting tracers may improve intraoperative identification of malignancy, facilitating precise excision. This study evaluates six potential FLI targets in OSCC, LSCC and PTC.

MATERIALS AND METHODS

Immunohistochemical staining was performed on OSCC (n = 20), LSCC (n = 10) and PTC (n = 10), assessing CEA, c-Met, EpCAM, EGFR, integrin αvβ6 and VEGF-α. Expression was scored (0-12) using the total immunostaining score (TIS) system, and categorized into absent (TIS 0), low (TIS 1-5), moderate (TIS 6-8) or high (TIS 9-12).

RESULTS

Integrin αvβ6 showed significant overexpression in OSCC (TIS: 12; p < 0.001) and LSCC (TIS: 8; p = 0.002), with 80% of OSCC and 90% of LSCC exhibiting moderate-high expression. Similarly, EGFR expression was moderate-high in most OSCC (87.5%; TIS: 8) and universally high in LSCC (100%; TIS: 12). In PTC, EGFR and VEGF-α expressions were low-moderate, but significantly higher than in healthy tissue (TIS: 6; p < 0.006).

CONCLUSION

This study highlights integrin αvβ6 and EGFR as viable FLI targets in OSCC and LSCC, especially integrin αvβ6 for tumour margin delineation. In PTC, despite lower expressions, the significant overexpression of VEGF-α, c-MET, and EGFR suggests their potential as FLI targets. Our findings support the development of tumour-targeted FLI tracers to improve surgical precision in HNC.

Preoperative [18F]fluoro-PEG-folate PET/CT in advanced stage epithelial ovarian cancer: A safety and feasibility study

PURPOSE

The selection for either primary or interval cytoreductive surgery (CRS) in patients with epithelial ovarian cancer (EOC) is currently based on imaging techniques like computed tomography (CT), [18F]fluorodeoxyglucose-positron emission tomography ([18F]FDG-PET), diffusion-weighted magnetic resonance imaging (DW-MRI) and/or diagnostic laparoscopy, but these have limitations. Folate receptor (FR)-targeted PET/CT imaging, using [18F]fluoro-PEG-folate, could improve preoperative assessment, potentially reducing unnecessary laparotomies. This paper presents the first experience with [18F]fluoro-PEG-folate PET/CT imaging in advanced stage EOC, focusing on safety, tolerability, and feasibility for reflecting the extent of disease.

METHODS

Tolerability and safety were monitored after administration of the [18F]fluoro-PEG-folate tracer by measurements of vital function parameters (blood pressure, heart rate, peripheral oxygen saturation, respiratory rate, and temperature). In addition, (serious) adverse events were recorded. Disease burden was quantified using the Peritoneal Cancer Index (PCI) score on preoperative [18F]fluoro-PEG-folate PET/CT and during surgery. PCI scores were compared with intraoperative findings, considering histopathologic results as the gold standard. Tissue specimens were stained for FRα and FRβ. Relative uptake of the radiotracer by EOC lesions and other tissues was quantified using body weighted standardized uptake values (SUV).

RESULTS

The study was terminated prematurely during the interim analysis after inclusion of eight patients of whom five had completed the study protocol. Although [18F]fluoro-PEG-folate demonstrated safety, efficacy for tumor-specific imaging was limited. Despite clear FRα overexpression, low tracer uptake was observed in EOC lesions, contrasting with high uptake in healthy tissues, posing challenges in specificity and accurately assessing tumor burden.

CONCLUSIONS

Overall, while [18F]fluoro-PEG-folate was well-tolerated, its clinical utility in the preoperative assessment of the extent of disease in EOC was limited. This highlights the need for further research in developing targeted imaging agents for optimal detection of EOC metastases.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT05215496. Registered 31 January 2022.

Targeting Human Pancreatic Cancer with a Fluorophore-Conjugated Mucin 4 (MUC4) Antibody: Initial Characterization in Orthotopic Cell Line Mouse Models

Background/Objectives: Pancreatic cancer is the third leading cause of death related to cancer. The only possible cure presently is complete surgical resection; however, this is limited by difficulty in clearly defining tumor margins. Enhancement of the visualization of pancreatic ductal adenocarcinoma (PDAC) tumor margins using near-infrared dye-conjugated tumor-specific antibodies was pioneered by using anti-CEA, anti-CA19.9, and anti-MUC5AC in orthotopic mouse models of pancreatic cancer. Recently, an antibody to Mucin 4 (MUC4) conjugated to a fluorescent probe has shown promise in targeting colon tumors in orthotopic mouse models. Methods: In the present study, we targeted pancreatic cancer using an anti-MUC4 antibody conjugated to IRDye800 (anti-MUC4-IR800) in orthotopic mouse models. Two pancreatic cancer human cell lines were used, SW1990 and CD18/HPAF. Results: Anti-MUC4-IR800 targeted the two pancreatic cancer cell line tumors in orthotopic mouse models with high tumor-to-pancreas ratios and high tumor-to-liver ratios, with greater targeting seen in SW1990. Conclusions: The present results suggest anti-MUC4-IR800's potential to be used in fluorescence-guided surgical resection of pancreatic cancer.

Frugal engineering-inspired wearable augmented reality goggle system enables fluorescence-guided cancer surgery

Disparities in surgical outcomes often result from subjective decisions dictated by surgical training, experience, and available resources. To improve outcomes, surgeons have adopted advancements in robotics, endoscopy, and intra-operative imaging including fluorescence-guided surgery (FGS), which highlights tumors and anatomy in real-time. However, technical, economic, and logistic challenges hinder widespread adoption of FGS beyond high-resource centers. To overcome these impediments, we combined laser diodes, Raspberry Pi cameras and computers, off-the-shelf optical components, and 3D-printed parts to make a battery-powered, compact, dual white light and NIR imaging system that has comparable performance to existing bulkier, pricier, and wall-powered technologies. We combined these components with off-the-shelf augmented reality (AR) glasses to create a fully-wearable fluorescence imaging AR Raspberry Pi-based goggle system (FAR-Pi) and validated performance in a pre-clinical cancer surgery model. Novel device design ensures distance-independent coalignment between real and augmented views. As an open-source, affordable, and adaptable system, FAR-Pi is poised to democratize access to FGS and improve health outcomes worldwide.

Novel anti-CEA affibody for rapid tumor-targeting and molecular imaging diagnosis in mice bearing gastrointestinal cancer cell lines

Gastrointestinal cancer is a common malignant tumor with a high incidence worldwide. Despite continuous improvements in diagnosis and treatment strategies, the overall prognosis of gastrointestinal tumors remains poor. Carcinoembryonic antigen (CEA) is highly expressed in various types of cancers, especially in gastrointestinal cancers, making it a potential target for therapeutic intervention. Therefore, the expression of CEA can be used as an indication of the existence of tumors, chosen as a target for molecular imaging diagnosis, and effectively utilized in the targeted therapy of gastrointestinal cancers. In this study, we report the selection and characterization of affibody molecules (ZCEA539, ZCEA546, and ZCEA919) specific to the CEA protein. Their ability to bind to recombinant and native CEA protein has been confirmed by surface plasmon resonance (SPR), immunofluorescence, and immunohistochemistry assays. Furthermore, Dylight755-labeled ZCEA affibody showed accumulation within the tumor site 1 h post injection and was continuously enhanced for 4 h. The Dylight755-labeled ZCEA affibody exhibited high tumor-targeting specificity in CEA+ xenograft-bearing mice and possesses promising characteristics for tumor-targeting imaging. Overall, our results suggest the potential use of ZCEA affibodies as fluorescent molecular imaging probes for detecting CEA expression in gastrointestinal cancer.

Progress of fluorescence imaging in lymph node dissection surgery for prostate and bladder cancer

Fluorescence imaging is a relatively new imaging method used to visualize different tissue structures to help guide intraoperative operations, which has potential advantages with high sensitivity and contrast compared to conventional imaging. In this work, we review fluorescent contrast agents and devices used for lymphatic system imaging. Indocyanine green is the most widely utilized due to its high sensitivity, specificity, low background fluorescence, and safety profile. In prostate and bladder cancer lymph node dissection, the complex lymphatic drainage can result in missed metastatic nodes and extensive dissection increases the risk of complications like lymphocele, presenting a significant challenge for urologists. Fluorescence-guided sentinel lymph node dissection facilitates precise tumor staging. The combination of fluorescence and radiographic imaging improves the accuracy of lymph node staging. Multimodal imaging presents new potential for precisely identifying metastatic pelvic lymph nodes.

Real-time detection and resection of sentinel lymph node metastasis in breast cancer through a rare earth nanoprobe based NIR-IIb fluorescence imaging

Sentinel lymph node (SLN) biopsy is a commonly employed procedure for the routine assessment of axillary involvement in patients with breast cancer. Nevertheless, conventional SLN mapping cannot reliably distinguish the presence and absence of metastatic disease. Additionally, the complex anatomical structures and lymphatic drainage patterns surrounding tumor sites pose challenges to the sensitivity of the near-infrared fluorescence imaging with subcutaneously injected probes. To identifying the SLN metastases, we developed a novel nanoprobe for in vivo fluorescence imaging within the second near-infrared (NIR-II) range. This nanoprobe utilizes rare-earth nanoparticles (RENPs) to emit bright fluorescence at 1525 nm and is conjugated with tumor-targeted hyaluronic acid (HA) to facilitate the detection of metastatic SLN. Upon intravenous administration, RENPs@HA effectively migrated to SLNs and selectively entered metastatic breast tumor cells through CD44-mediated endocytosis. The RENPs@HA nanoprobes exhibited rapid accumulation in metastatic inguinal lymph nodes in mouse model, displaying a 5.8-fold-stronger fluorescence intensity to that observed in normal SLNs. Consequently, these nanoprobes effectively differentiate metastatic SLNs from normal SLNs. Importantly, the probes accurately detected micrometastases. These findings underscore the potential of RENPs@HA for real-time visualization and screening of SLNs metastasis.

Nerve-Sparing Gynecologic Surgery Enabled by A Near-Infrared Nerve-Specific Fluorophore Using Existing Clinical Fluorescence Imaging Systems

Patients undergoing gynecological procedures suffer from lasting side effects due to intraoperative nerve damage. Small, delicate nerves with complex and nonuniform branching patterns in the female pelvic neuroanatomy make nerve-sparing efforts during standard gynecological procedures such as hysterectomy, cystectomy, and colorectal cancer resection difficult, and thus many patients are left with incontinence and sexual dysfunction. Herein, a near-infrared (NIR) fluorescent nerve-specific contrast agent, LGW08-35, that is spectrally compatible with clinical fluorescence guided surgery (FGS) systems is formulated and characterized for rapid implementation for nerve-sparing gynecologic surgeries. The toxicology, pharmacokinetics (PK), and pharmacodynamics (PD) of micelle formulated LGW08-35 are examined, enabling the determination of the optimal imaging doses and time points, blood and tissue uptake parameters, and maximum tolerated dose (MTD). Application of the formulated fluorophore to imaging of female rat and swine pelvic neuroanatomy validates the continued clinical translation and use for real-time identification of important nerves such as the femoral, sciatic, lumbar, iliac, and hypogastric nerves. Further development of LGW08-35 for clinical use will unlock a valuable tool for surgeons in direct visualization of important nerves and contribute to the ongoing characterization of the female pelvic neuroanatomy to eliminate the debilitating side effects of nerve damage during gynecological procedures.

Interim Phase II Results Using Panitumumab-IRDye800CW during Transoral Robotic Surgery in Patients with Oropharyngeal Cancer

PURPOSE

The incidence of oropharyngeal squamous cell carcinoma (OPSCC) has continually increased during the past several decades. Using transoral robotic surgery (TORS) significantly improves functional outcomes relative to open surgery for OPSCC. However, TORS limits tactile feedback, which is often the most important element of cancer surgery. Fluorescence-guided surgery (FGS) strategies to aid surgeon assessment of malignancy for resection are in various phases of clinical research but exhibit the greatest potential impact for improving patient care when the surgeon receives limited tactile feedback, such as during TORS. Here, we assessed the feasibility of intraoperative fluorescence imaging using panitumumab-IRDye800CW (PAN800) during TORS in patients with OPSCC.

PATIENTS AND METHODS

Twelve consecutive patients with OPSCC were enrolled as part of a nonrandomized, prospective, phase II FGS clinical trial using PAN800. TORS was performed with an integrated robot camera for surgeon assessment of fluorescence. Intraoperative and ex vivo fluorescence signals in tumors and normal tissue were quantified and correlated with histopathology.

RESULTS

Intraoperative robot fluorescence views delineated OPSCC from normal tissue throughout the TORS procedure (10.7 mean tumor-to-background ratio), including in tumors with low expression of the molecular target. Tumor-specific fluorescence was consistent with surgeon-defined tumor borders requiring resection. Intraoperative robot fluorescence imaging revealed an OPSCC fragment initially overlooked during TORS based on brightfield views, further substantiating the clinical benefit of this FGS approach.

CONCLUSIONS

The results from this patient with OPSCC cohort support further clinical assessment of FGS during TORS to aid resection of solid tumors.

Illuminating the future of precision cancer surgery with fluorescence imaging and artificial intelligence convergence

Real-time and accurate guidance for tumor resection has long been anticipated by surgeons. In the past decade, the flourishing material science has made impressive progress in near-infrared fluorophores that may fulfill this purpose. Fluorescence imaging-guided surgery shows great promise for clinical application and has undergone widespread evaluations, though it still requires continuous improvements to transition this technique from bench to bedside. Concurrently, the rapid progress of artificial intelligence (AI) has revolutionized medicine, aiding in the screening, diagnosis, and treatment of human doctors. Incorporating AI helps enhance fluorescence imaging and is poised to bring major innovations to surgical guidance, thereby realizing precision cancer surgery. This review provides an overview of the principles and clinical evaluations of fluorescence-guided surgery. Furthermore, recent endeavors to synergize AI with fluorescence imaging were presented, and the benefits of this interdisciplinary convergence were discussed. Finally, several implementation strategies to overcome technical hurdles were proposed to encourage and inspire future research to expedite the clinical application of these revolutionary technologies.

Tuning nanoparticle core composition drives orthogonal fluorescence amplification for enhanced tumour imaging

Tumour detection with high selectivity and sensitivity is crucial for delineating tumour margins and identifying metastatic foci during image-guided surgery. Optical nanoprobes with preferential tumour accumulation is often limited by inefficient amplification of biological signals. Here, we report the design of a library of hydrophobic core-tunable ultra-pH-sensitive nanoprobes (HUNPs) for orthogonally amplifying tumour microenvironmental signals on multiple tumour models. We find that tuning the hydrophobicity of nanoparticle core composition with non-ionizable monomers can enhance cellular association of HUNPs by more than ten-fold, resulting in a high cellular internalization efficiency of HUNPs with up to 50% in tumours. Combining high tumour accumulation and high cell internalization efficiency, HUNPs show orthogonally amplified fluorescence signals, permitting the precise locating and delineating margins between malignant lesions and normal tissues with high contrast-to-noise ratio and resolution. Our study provides key strategies to design nanomedicines with high intracellular bioavailability for cancer detection, drug/gene delivery, and therapy.

Dual-Modal Near-Infrared Organic Nanoparticles: Integrating Mild Hyperthermia Phototherapy with Fluorescence Imaging

Purpose

Our study seeks to develop dual-modal organic-nanoagents for cancer therapy and real-time fluorescence imaging, followed by their pre-clinical evaluation on a murine model. Integrating NIR molecular imaging with nanotechnology, our aim is to improve outcomes for early-stage cutaneous melanoma by offering more effective and less invasive methods. This approach has the potential to enhance both photothermal therapy (PTT) and Sentinel Lymph Node Biopsy (SLNB) procedures for melanoma patients.

Methods

NIR-797-isothiocyanate was encapsulated in poly(D,L-lactide-co-glycolide) acid (PLGA) nanoparticles (NPs) using a two-step protocol, followed by thorough characterization, including assessing loading efficiency, fluorescence stability, and photothermal conversion. Biocompatibility and cellular uptake were tested in vitro on melanoma cells, while PTT assay, with real-time thermal monitoring, was performed in vivo on tumor-bearing mice under irradiation with an 808 nm laser. Finally, ex vivo fluorescence microscopy, histopathological assay, and TEM imaging were performed.

Results

Our PLGA NPs, with a diameter of 270 nm, negative charge, and 60% NIR-797 loading efficiency, demonstrated excellent stability and fluorescence properties, as well as efficient light-to-heat conversion. In vitro studies confirmed their biocompatibility and cellular internalization. In vivo experiments demonstrated their efficacy as photothermal agents, inducing mild hyperthermia with temperatures reaching up to 43.8 °C. Ex vivo microscopy of tumor tissue confirmed persistent NIR fluorescence and uniform distribution of the NPs. Histopathological and TEM assays revealed early apoptosis, immune cell response, ultrastructural damage, and intracellular material debris resulting from combined NP treatment and irradiation. Additionally, TEM analyses of irradiated zone margins showed attenuated cellular damage, highlighting the precision and effectiveness of our targeted treatment approach.

Conclusion

Specifically tailored for dual-modal NIR functionality, our NPs offer a novel approach in cancer PTT and real-time fluorescence monitoring, signaling a promising avenue toward clinical translation.

Injectable and Sprayable Fluorescent Nanoprobe for Rapid Real-Time Detection of Human Colorectal Tumors

The development of minimally invasive surgery has greatly advanced precision tumor surgery, but sometime suffers from restricted visualization of the surgical field, especially during the removal of abdominal tumors. A 3-D inspection of tumors could be achieved by intravenously injecting tumor-selective fluorescent probes, whereas most of which are unable to instantly distinguish tumors via in situ spraying, which is urgently needed in the process of surgery in a convenient manner. In this study, this work has designed an injectable and sprayable fluorescent nanoprobe, termed Poly-g-BAT, to realize rapid tumor imaging in freshly dissected human colorectal tumors and animal models. Mechanistically, the incorporation of γ-glutamyl group facilitates the rapid internalization of Poly-g-BAT, and these internalized nanoprobes can be subsequently activated by intracellular NAD(P)H: quinone oxidoreductase-1 to release near-infrared fluorophores. As a result, Poly-g-BAT can achieve a superior tumor-to-normal ratio (TNR) up to 12.3 and enable a fast visualization (3 min after in situ spraying) of tumor boundaries in the xenograft tumor models, Apcmin/+ mice models and fresh human tumor tissues. In addition, Poly-g-BAT is capable of identifying minimal premalignant lesions via intravenous injection.

Optimized Two-Photon Imaging by Stimuli-Responsive Peptide Self-Assembly Facilitates Self-Assisted Counteraction of Cisplatin-Resistance in Cancer Cells

Accurate diagnosis and effective treatment of tumors remain significant clinical challenges. While fluorescence imaging is essential for tumor detection, it has limitations in terms of specificity, penetration depth, and emission wavelength. Here, we report a novel glutathione (GSH)-responsive peptide self-assembly excimer probe (pSE) that optimizes two-photon tumor imaging and self-assisted counteraction of the cisplatin resistance in cancer cells. The GSH-responsive self-assembly of pSE induces a monomer-excimer transition of coumarin, promoting a near-infrared redshift of fluorescence emission under two-photon excitation. This process enhances penetration depth and minimizes interference from biological autofluorescence. Moreover, the intracellular self-assembly of pSE impacts GSH homeostasis, modulates relevant signaling pathways, and significantly reduces GSTP1 expression, resulting in decreased cisplatin efflux in cisplatin-resistant cancer cells. The proposed self-assembled excimer probe not only distinguishes cancer cells from normal cells but also enhances the efficacy of cisplatin chemotherapy, offering significant potential in tumor diagnosis and overcoming cisplatin-resistant tumors.

Generation and Characterization of Novel Pan-Cancer Anti-uPAR Fluorescent Nanobodies as Tools for Image-Guided Surgery

Fluorescence molecular imaging plays a vital role in image-guided surgery. In this context, the urokinase plasminogen activator receptor (uPAR) is an interesting biomarker enabling the detection and delineation of various tumor types due to its elevated expression on both tumor cells and the tumor microenvironment. In this study, anti-uPAR Nanobodies (Nbs) are generated through llama immunization with human and murine uPAR protein. Extensive in vitro characterization and in vivo testing with radiolabeled variants are conducted to assess their pharmacokinetics and select lead compounds. Subsequently, the selected Nbs are converted into fluorescent agents, and their application for fluorescence-guided surgery is evaluated in various subcutaneous and orthotopic tumor models. The study yields a panel of high-affinity anti-uPAR Nbs, showing specific binding across multiple types of cancer cells in vitro and in vivo. Lead fluorescently-labeled compounds exhibit high tumor uptake with high contrast at 1 h after intravenous injection across all assessed uPAR-expressing tumor models, outperforming a non-targeting control Nb. Additionally, rapid and accurate tumor localization and demarcation are demonstrated in an orthotopic human glioma model. Utilizing these Nbs can potentially enhance the precision of surgical tumor resection and, consequently, improve survival rates in the clinic.

An ultra-small organic dye nanocluster for enhancing NIR-II imaging-guided surgery outcomes

PURPOSE

The accuracy of surgery for patients with solid tumors can be greatly improved through fluorescence-guided surgery (FGS). However, existing FGS technologies have limitations due to their low penetration depth and sensitivity/selectivity, which are particularly prevalent in the relatively short imaging window (< 900 nm). A solution to these issues is near-infrared-II (NIR-II) FGS, which benefits from low autofluorescence and scattering under the long imaging window (> 900 nm). However, the inherent self-assembly of organic dyes has led to high accumulation in main organs, resulting in significant background signals and potential long-term toxicity.

METHODS

We rationalize the donor structure of donor-acceptor-donor-based dyes to control the self-assembly process to form an ultra-small dye nanocluster, thus facilitating renal excretion and minimizing background signals.

RESULTS

Our dye nanocluster can not only show clear vessel imaging, tumor and tumor sentinel lymph nodes definition, but also achieve high-performance NIR-II imaging-guided surgery of tumor-positive sentinel lymph nodes.

CONCLUSION

In summary, our study demonstrates that the dye nanocluster-based NIR-II FGS has substantially improved outcomes for radical lymphadenectomy.

hHEPATO-Cy5, a Bimodal Tracer for Image-Guided Hepatobiliary Surgery

Liver cancer is a leading cause of cancer deaths worldwide. Surgical resection of superficial hepatic lesions is increasingly guided by the disrupted bile excretion of the fluorescent dye indocyanine green (ICG). To extend this approach to deeper lesions, a dedicated bimodal tracer that facilitates both fluorescence guidance and radioguidance was developed. Methods: A tracer comprising a methylated cyanine-5 (Cy5) fluorescent dye and a mercaptoacetyltriserine chelate (hHEPATO-Cy5) was synthesized and characterized. Cellular uptake and excretion were evaluated in hepatocyte cultures (2-dimensional culture and in vitro lesion model), using a fluorescent bile salt, MitoTracker dye, and methylated Cy5 as a control. After radiolabeling, the pharmacokinetics of 99mTc-hHEPATO-Cy5 were assessed in mice over 24 h (percentage injected dose and percentage injected dose per gram of tissue, SPECT/CT imaging and fluorescence imaging). The ability to provide real-time fluorescence guidance during robot-assisted hepatobiliary surgery was evaluated in a porcine model using ICG as a reference. Results: The unique molecular signature of hHEPATO-Cy5 promotes hepatobiliary excretion. In vitro studies on hepatocytes showed that where methylated Cy5 remained internalized, hHEPATO-Cy5 showed fast clearance (10 min) similar to that of fluorescent bile salt. In vivo use of 99mTc-hHEPATO-Cy5 in mice revealed liver accumulation and rapid biliary clearance. The effectiveness of bile clearance was best exemplified by the 2-orders-of-magnitude reduction in count rate for the gallbladder (P = 0.008) over time. During hepatobiliary surgery in a porcine model, hHEPATO-Cy5 enabled fluorescence-based lesion identification comparable to that of ICG. Conclusion: The bimodal 99mTc-hHEPATO-Cy5 provides an effective means to identify liver lesions. Uniquely, it helps overcome the shortcomings of fluorescence-only approaches by allowing for an extension to in-depth radioguidance.