"Zero" Intrinsic Fluorescence Sensing-Platforms Enable Ultrasensitive Whole Blood Diagnosis and In Vivo Imaging

Abnormal physiological processes and diseases can lead to content or activity fluctuations of biocomponents in organelles and whole blood. However, precise monitoring of these abnormalities remains extremely challenging due to the insufficient sensitivity and accuracy of available fluorescence probes, which can be attributed to the background fluorescence arising from two sources, 1) biocomponent autofluorescence (BCAF) and 2) probe intrinsic fluorescence (PIF). To overcome these obstacles, we have re-engineered far-red to NIR II rhodol derivatives that possess weak BCAF interference. And a series of "zero" PIF sensing-platforms were created by systematically regulating the open-loop/spirocyclic forms. Leveraging these advancements, we devised various ultra-sensitive NIR indicators, achieving substantial fluorescence boosts (190 to 1300-fold). Among these indicators, 8-LAP demonstrated accurate tracking and quantifying of leucine aminopeptidase (LAP) in whole blood at various stages of tumor metastasis. Furthermore, coupling 8-LAP with an endoplasmic reticulum-targeting element enabled the detection of ERAP1 activity in HCT116 cells with p53 abnormalities. This delicate design of eliminating PIF provides insights into enhancing the sensitivity and accuracy of existing fluorescence probes toward the detection and imaging of biocomponents in abnormal physiological processes and diseases.

An ingestible near-infrared fluorescence capsule endoscopy for specific gastrointestinal diagnoses

Early diagnosis of gastrointestinal (GI) diseases is important to effectively prevent carcinogenesis. Capsule endoscopy (CE) can address the pain caused by wired endoscopy in GI diagnosis. However, existing CE approaches have difficulty effectively diagnosing lesions that do not exhibit obvious morphological changes. In addition, the current CE cannot achieve wireless energy supply and attitude control at the same time. Here, we successfully developed a novel near-infrared fluorescence capsule endoscopy (NIFCE) that can stimulate and capture near-infrared (NIR) fluorescence images to specifically identify subtle mucosal microlesions and submucosal lesions while capturing conventional white light (WL) images to detect lesions with significant morphological changes. Furthermore, we constructed the first synergetic system that simultaneously enables multi-attitude control in NIFCE and supplies long-term power, thus addressing the issue of excessive power consumption caused by the NIFCE emitting near-infrared light (NIRL). We performed in vivo experiments to verify that the NIFCE can specifically "light up" tumors while sparing normal tissues by synergizing with probes actively aggregated in tumors, thus realizing specific detection and penetration. The prototype NIFCE system represents a significant step forward in the field of CE and shows great potential in efficiently achieving early targeted diagnosis of various GI diseases.

Clinicopathological factors associated with sentinel lymph node detection in non-small-cell lung cancer

BACKGROUND

Mapping of the pulmonary lymphatic system by near-infrared (NIR) fluorescence imaging might not always identify the first lymph node relay. The aim of this study was to determine the clinicopathologic factors allowing the identification of sentinel lymph nodes (SLNs) by NIR fluorescence imaging in thoracic surgery for non-small-cell lung cancer (NSCLC).

METHODS

We conducted a retrospective review of 92 patients treated for suspected or confirmed cN0 lung cancer with curative intent who underwent an intraoperative injection of indocyanine green (ICG) either by direct peritumoral injection or by endobronchial injection using electromagnetic navigational bronchoscopy (ENB). After exclusion of patients for technical failure, benign disease and metastasis, we analyzed the clinicopathologic findings of 65 patients treated for localized-stage NSCLC, comparing the group with identification of SLNs (SLN-positive group) with the group without identification of SLNs (SLN-negative group).

RESULTS

Forty-eight patients (73.8%) were SLN-positive. Patients with SLN positivity were more frequently female (50%) than the SLN-negative patients were (11.8%) (p = 0.006). The mean value of diffusing capacity for carbon monoxide (DLCO) was lower among the patients in the SLN-negative group (64.7% ± 16.7%) than the SLN-positive group (77.6% ± 17.2%, p < 0.01). The ratio of forced expiratory volume in one second to forced vital capacity (FEV1/FCV) was higher in the SLN-positive group (69.0% vs. 60.8%, p = 0.02). Patients who were SLN-negative were characterized by a severe degree of emphysema (p = 0.003). There was no significant difference in pathologic characteristics. On univariate analyses, age, female sex, DLCO, FEV1/FVC, degree of emphysema, and tumor size were significantly associated with SLN detection. On multivariate analysis, DLCO > 75% (HR = 4.92, 95% CI: 1.27-24.7; p = 0.03) and female sex (HR = 5.55, 95% CI: 1.25-39.33; p = 0.04) were independently associated with SLN detection.

CONCLUSIONS

At a time of resurgence in the use of the sentinel lymph node mapping technique in the field of thoracic surgery, this study enabled us to identify, using multivariate analysis, two predictive factors for success: DLCO > 75% and female sex. Larger datasets are needed to confirm our results.

Advances in the Treatment of Chylothorax

Idiopathic chylothorax is a challenging clinical condition historically associated with poor resolution rates following surgical intervention. Recent advances in imaging and surgical techniques have revolutionized the treatment of this disease process. Computed tomographic lymphangiography has facilitated improved surgical planning and postoperative assessment, while intraoperative use of near-infrared fluorescence imaging aids in highly accurate intraoperative thoracic duct identification. Utilizing these advancements, minimally invasive surgical techniques have been successfully developed and have been associated with considerable improvements in surgical outcomes.

Neo-construction of a SO2-tunable near-infrared ratiometric fluorescent probe for high-fidelity diagnosis and evaluation hazards of Cd2+-induced liver injury

Cadmium-contaminated water and food are seriously hazardous to the human health, especially liver injury. To understand the entanglement relationship between cadmium ion (Cd2+)-induced liver injury and the biomarker sulfur dioxide (SO2), a reliable bioanalytical tool is urgently needed, detecting SO2 to diagnose and evaluate the extent of liver injury in vivo. Herein, based on the Förster resonance energy transfer (FRET) mechanism, a novel SO2-tunable NIR ratiometric fluorescent probe (SMP) was developed, it was used to diagnose and treat liver injury induced by Cd2+ in biosystems. Specifically, it was constructed by conjugating a NIR dicyanoisophorone with a NIR benzopyranate as the donor and acceptor, respectively, and the ratiometric response of SO2- regulated by the Michael addition reaction. In addition, SMP exhibits rapid reaction time (<15 s), two well-resolved emission peaks (68 nm) with less cross-talk between channels for high imaging resolution, superior selectivity, and low limit of detection (LOD=80.3 nM) for SO2 detection. Impressively, SMP has been successfully used for intracellular ratiometric imaging of Cd2+-induced SO2 and diagnostic and therapeutic evaluation in liver injury mice models with satisfactory results. Therefore, SMP may provide a powerful molecular tool for revealing the occurrence and development relationship between SO2 and Cd2+-induced liver injury. ENVIRONMENTAL IMPLICATION: Cadmium ions are one of the well-known toxic environmental pollutants, which are enriched in the human body through inhalation of cadmium-contaminated air or from the food chain, leading to damage in various organs, especially liver injury. Therefore, we developed a novel fluorescent probe that can specifically detect SO2 in Cd2+-induced liver injury, which is critically important for the diagnosis and evaluation of Cd2+-induced liver injury diseases. The specific detection of SO2 of this probe has been successfully demonstrated in live HepG2 cells and Cd2+-induced liver injury mice.

Blood flow evaluation of reconstructed gastric tube in esophageal surgery using near-infrared imaging and retrospective time-intensity curve analysis

PURPOSE

Near-infrared fluorescence imaging using indocyanine green (ICG-NIFI) can visualize a blood flow in reconstructed gastric tube; however, it depends on surgeon's visual assessment. The aim of this study was to re-analyze the ICG-NIFI data by an evaluator independent from the surgeon and feasibility of creating the time-intensity curve (TIC).

METHODS

We retrospectively reviewed 97 patients who underwent esophageal surgery with gastric tube reconstruction between January 2017 and November 2022. From the stored ICG videos, fluorescence intensity was examined in the four regions of interest (ROIs), which was set around the planned anastomosis site on the elevated gastric tube. After creation the TICs using the OpenCV library, we measured the intensity starting point and time constant and assessed the correlation between the anastomotic leakage.

RESULTS

Postoperative leakage occurred for 12 patients. The leakage group had significantly lack of blood flow continuity between the right and left gastroepiploic arteries (75.0% vs. 22.4%; P < 0.001) and tended to have slower ICG visualization time assessed by the surgeon's eyes (40 vs. 32 s; P = 0.066). TIC could create in 65 cases. Intensity starting point at all ROIs was faster than the surgeon's assessment. The leakage group tended to have slower intensity starting point at ROI 3 compared to those in the non-leakage group (22.5 vs. 19.0 s; P = 0.087).

CONCLUSION

A TIC analysis of ICG-NIFI by an independent evaluator was able to quantify the fluorescence intensity changes that the surgeon had visually determined.

A near-infrared fluorescent probe for rapid and on-site detection of sulfur dioxide derivative in biological, food and environmental systems

Emission of toxic gaseous sulfur dioxide (SO2) and its derivative bisulfite (HSO3-) from various industrial applications, like food processing, transportation, and the coking process, has raised substantial concerns regarding environmental quality and public health. The probes for specific and sensitive detection of SO2 derivatives plays an essential role in their regulation, and ultimately mitigating their environmental and health implications, but the one that can detect SO2 derivatives onsite by end users remains limited. Herein, we report a new near-infrared fluorescence probe (SL) for rapid and onsite detection of SO2 derivative, HSO3- in industrial wastewater, food samples and for sensing its interaction with biological organisms. The SL is developed through coupling of quinolinium and coumarin moiety through an electron deficit CC bond that can specifically react with HSO3- via a Michael addition. By recording the blue shift of absorption and emission spectra, SL can sensitively detect HSO3- (limit of detection, 38 nM) in aqueous solution within 40 s SL is biocompatible, can be used for evaluating toxicity of SO2 derivatives in living organisms. The preparation of SL-stained test paper allows the colorimetric/fluorometric analysis for quantification of HSO3- onsite in food, river and coking wastewater samples using a smartphone. The successful development of SL not only provides a new tool to investigate HSO3- in biological, food and environmental systems, but also potentially promotes the application of fluorescence technique for rapid and onsite analysis of real-world samples by end users.

Dual-mode fluorescence and colorimetric sensing of sulfide anion in natural water based on near-infrared Ag2S quantum dots and MnO2 nanosheets complex

Near infrared (NIR) emission Ag2S quantum dots (QDs) are of great value for biochemical sensing with strong anti-interference and low toxicity. Herein, NIR fluorescence Ag2S QDs were synthesized successfully. Combined with the excellent oxidase-like characteristics of manganese dioxide (MnO2) nanosheets, a fluorescence and colorimetric dual-mode sensor for sulfide anion was developed. MnO2 nanosheets could effectively catalyze the oxidation of TMB to produce blue TMB oxide (ox TMB), at the same time, the fluorescence of Ag2S QDs could be effectively quenched by fluorescence internal filtration effect (IFE) and dynamic quenching effect. The enzyme-like activity was weakened and the NIR fluorescence of Ag2S QDs was restored when sulfide anion (S2-) was added, due to the reduction of MnO2 to Mn2+.The linear ranges for fluorescence and colorimetric analysis of S2- were 2-250 μM and 0.3-50 μM, with detection limits of 0.6 and 0.215 μM, correspondingly. The dual-mode sensor had a wider detection range, higher sensitivity and shorter reaction time, which could be used for highly selective detection of S2- in different concentration ranges. In addition, it had been successfully applied to the determination of sulfide in water samples with satisfactory accuracy and sensitivity.

Real-time visualization the pH fluctuations of living cells with a ratiometric near-infrared fluorescent probe

In situ real-time quantitative monitoring pH fluctuation in complex living systems is vitally significant. In the current work, a ratiometric near-infrared (NIR) probe (MCyOH) was developed to confront this challenge. MCyOH exhibited good sensitivity, photostability, reversibility, and an ideal pKa (pKa = 6.65). Ratiometric character of MCyOH is beneficial to accuracy detect the pH fluctuations in living cells under different stimulation. The observations showed that intracellular pH was decreased when HepG2 cells under oxidative stress or starvation conditions. In particular, HepG2 cells was acidulated after addition of ethanol, however, the acidification phenomenon was attenuated or disappeared when HepG2 cells preincubated with disulfiram or fomepizole. Finally, MCyOH was successfully applied to observe the increasement of intracellular pH when HepG2 cells treated with fomepizole individually. Overall, MCyOH would be a practical candidate to explore pH-associated physiological and pathological varieties.

Transhepatic arterial approaches for ICG injection to guide laparoscopic anatomical hepatectomy: A case series study

BACKGROUND

Laparoscopic anatomical hepatectomy guided by near-infrared fluorescence imaging (NIR-FI) has been utilized extensively. However, it is difficult to resect "cone units" above the third branch of the Glissonean pedicle in the right posterior lobe using the laparoscopic positive or negative staining techniques. Therefore, we undertook a new laparoscopic segmentectomy based on the concept of "cone unit" assisted by interventional radiology combined with NIR-FI.

METHODS

Laparoscopic segmentectomy guided by NIR-FI via super-selective hepatic arteriography and trans-arterial injection of ICG was carried out on 13 patients with early-stage HCC between September 2020 and January 2022.11 of cases were successful, and relevant pathological characteristics and perioperative outcomes were retrospectively analyzed.

RESULTS

Two cases failed NIR-FI out of which one case involved over-staining to the non-target segment, and in the other case, which was to undergo laparoscopic segment V resection, only the ventral segment was stained while the imaging of the dorsal segment failed. In the intraoperative conditions, the tumor safe margin was 1.1 (0.7-1.55) cm, the interventional operation time was 50 (45.5-60.5) minutes, the operation time was 280 (242.5-307.5) minutes, the blood loss was 100 (50-200) ml, the postoperative hospital stay was 5 (4.5-5.5) days. No cases converted to laparotomy, and no serious postoperative complications developed.

CONCLUSIONS

NIR-FI through super-selective hepatic arteriography and trans-arterial injection of ICG can provide a clear and lasting navigation aid for laparoscopic segmentectomy, which may have positive implication for early-stage HCC with poor preoperative liver reserves.

The use of indocyanine green in partial nephrectomy: a systematic review

Introduction

The aim of this review was to assess the outcomes of partial nephrectomy using indocyanine green (ICG) regarding ischemia time, positive surgical margins (PSM), estimated blood loss (EBL) and estimated GFR reduction while also suggesting the optimal dosage scheme.

Material and methods

A systematic review was performed using Medline (PubMed), ClinicalTrials.gov, and Cochrane Library (CENTRAL) databases, in concordance with the PRISMA statement. Studies in English regarding the use of indocyanine green in partial nephrectomy were reviewed. Reviews and meta-analyses, editorials, perspectives, and letters to the editors were excluded.

Results

Individual ICG dose was 5 mg in most of the studies. The mean warm ischemia time (WIT) on each study ranged from 11.6 minutes to 27.2 minutes. The reported eGFR reduction ranged from 0% to 15.47%. Lowest mean EBL rate was 48.2 ml and the highest was 347 ml. Positive surgical margin rates were between 0.3% to 11%.

Conclusions

Indocyanine green seems to be a useful tool in partial nephrectomy as it can assist surgeons in identifying tumor and its related vasculature. Thereby, warm ischemia time can be reduced and, in some cases, selective ischemia can be implemented leading to better renal functional preservation.

Lower-grade gliomas surgery guided by GRPR-targeting PET/NIR dual-modality image probe: a prospective and single-arm clinical trial

Purpose: Lower-grade gliomas (LGGs) are a group of infiltrative growing glial brain tumors characterized by intricate intratumoral heterogeneity and subtle visual appearance differences from non-tumor tissue, which can lead to errors in pathologic tissue sampling. Although 5-ALA fluorescence has been an essential method for visualizing gliomas during surgery, its effectiveness is limited in the case of LGGs due to low sensitivity. Therefore, we developed a novel PET/NIR dual-modality image probe targeting gastrin-releasing peptide receptor (GRPR) in glioma cells to enhance tumor visualization and improve the accuracy of sampling. Methods: A prospective, non-randomized, single-center feasibility clinical trial (NCT03407781) was conducted in the referral center from October 21, 2016, to August 17, 2018. Consecutive enrollment included patients suspected of having LGGs and considered suitable candidates for surgical removal. Group 1 comprised ten patients who underwent preoperative 68Ga-IRDye800CW-BBN PET/MRI assessment followed by intraoperative fluorescence-guided surgery. Group 2 included 42 patients who underwent IRDye800CW-BBN fluorescence-guided surgery. The primary endpoints were the predictive value of preoperative PET imaging for intraoperative fluorescence and the sensitivity and specificity of fluorescence-guided sampling. Results: Thirty-nine patients were included in the in-depth analysis of endpoints, with 25 (64.1%) exhibiting visible fluorescence, while 14 (35.9%) did not. The preoperative positive PET uptake exhibited a greater accuracy in predicting intraoperative fluorescence compared to MRI enhancement (100% [10/10] vs. 87.2% [34/39]). A total of 125 samples were harvested during surgery. Compared with pathology, subjective fluorescence intensity showed a sensitivity of 88.6% and a specificity of 88.2% in identifying WHO grade III samples. For WHO grade II samples, the sensitivity and specificity of fluorescence were 54.7% and 88.2%, respectively. Conclusion: This study has demonstrated the feasibility of the novel dual-modality imaging technique for integrated pre- and intraoperative targeted imaging via the same molecular receptor in surgeries for LGGs. The PET/NIR dual-modality probe exhibits promise for preoperative surgical planning in fluorescence-guided surgery and provides greater accuracy in guiding tumor sampling compared to 5-ALA in patients with LGGs.

A NIR ratiometric fluorescent probe for the rapid detection of hydrogen sulfide in living cells and zebrafish

Hydrogen sulfide (H2S) acts as a gas transporter and cell protector and plays a role in a number of disorders and signaling processes. Given that the half-life of H2S in biological systems is between seconds and minutes, the development of rapid and accurate technologies for reliable monitoring H2S levels and dynamics in organisms is critical. However, it is still difficult to design innovative near-infrared fluorescent probes that can quickly and accurately detect H2S. Here, we constructed a novel NIR ratiometric fluorescent probe based on the "aldehyde group auxiliary strategy", Cy-H2S, for the quantitative detection and precise imaging of H2S in living cells and zebrafish. Cy-H2S responded quickly (150 s) and was highly sensitive (0.179 μM) to H2S donor. Cy-H2S was further successfully employed to track endogenous H2S fluctuation in HCT116 cells and zebrafish and evaluated the release efficiency of the H2S prodrug in a NIR ratiometric imaging way. Cy-H2S has the potential to be used as a reliable indication of H2S levels in living cells and zebrafish, as well as an innovative and practical instrument for furthering the physiological research of H2S, which will encourage the creation of advanced NIR ratiometric probes for a variety of biological applications.

Near-infrared fluorescence tattooing: a new approach for endoscopic marking of tumors in minimally invasive colorectal surgery using a persistent near-infrared marker

INTRODUCTION

Intraoperative accurate localization of tumors in the lower gastrointestinal tract is essential to ensure oncologic radicality. In minimally invasive colon surgery, tactile identification of tumors is challenging due to diminished or absent haptics. In clinical practice, preoperative endoscopic application of a blue dye (ink) to the tumor site has become the standard for marking and identification of tumors in the colon. However, this method has the major limitation that accidental intraperitoneal spillage of the dye can significantly complicate the identification of anatomical structures and surgical planes. In this work, we describe a new approach of NIR fluorescent tattooing using a near-infrared (NIR) fluorescent marker instead of a blue dye (ink) for endoscopic tattooing.

METHODS

AFS81x is a newly developed NIR fluorescent marker. In an experimental study with four domestic pigs, the newly developed NIR fluorescent marker (AFS81x) was used for endoscopic tattooing of the colon. 7-12 endoscopic submucosal injections of AFS81x were placed per animal in the colon. On day 0, day 1, and day 10 after endoscopic tattooing with AFS81x, the visualization of the fluorescent markings in the colon was evaluated during laparoscopic surgery by two surgeons and photographically documented.

RESULTS

The detection rate of the NIR fluorescent tattoos at day 0, day 1, and day 10 after endoscopic tattooing was 100%. Recognizability of anatomical structures during laparoscopy was not affected in any of the markings, as the markings were not visible in the white light channel of the laparoscope, but only in the NIR channel or in the overlay of the white light and the NIR channel of the laparoscope. The brightness, the sharpness, and size of the endoscopic tattoos did not change significantly on day 1 and day 10, but remained almost identical compared to day 0.

CONCLUSION

The new approach of endoscopic NIR fluorescence tattooing using the newly developed NIR fluorescence marker AFS81x enables stable marking of colonic sites over a long period of at least 10 days without compromising the recognizability of anatomical structures and surgical planes in any way.

Tunable Aggregation-induced Emission and Emission Colors of Imidazolium and Pyridinium Based Hydrazones

Aggregation-induced emission (AIE) materials have drawn great attention for their wide applications as optical materials. The applications of AIE materials, however, are restricted by the complicated syntheses, hydrophobic properties and short emission wavelengths. Herein, an imidazolium based hydrazone (E)-1-(4-methoxyphenyl)-2-((1-methyl-1H-imidazol-2-yl)methylene)hydrazine hydrochloride (1) and a pyridinium based hydrazone (E)-1-(4-methoxyphenyl)-2-(pyridin-4-ylmethylene)hydrazine hydrochloride (2) have been synthesized. Notably, 1 and 2 in crystals show distinct green and near-infrared (NIR) fluorescence, with emission peaks at 530 and 688 nm, and Stokes shifts of 176 and 308 nm, respectively. After grinding the crystals to powder, the absolute fluorescence quantum yield (ΦF) of 1 is increased from 4.2% to 10.6%, and the ΦF of 2 is increased from 0.2% to 0.7%. X-ray crystallography studies together with theoretical calculations indicate that the enhanced emission of 1 arises from hydrogen bonding induced rigid network, and the fluorescence in the NIR region and large Stokes shift of 2 are attributed to its twisted molecular structure and strong push-pull effect.

The utility of fluorescence imaging in detecting primary and metastatic small bowel carcinoid tumors

BACKGROUND

Our aim was to investigate utility of indocyanine green (ICG) and autofluorescence (AF) imaging in detection of small bowel primary and metastatic carcinoids.

METHODS

Using Institutional Review Board approval, ICG and AF imaging of small bowel carcinoids was performed. Imaging findings were prospectively recorded in operating room and compared with conventional imaging, surgical exploration and pathologic findings.

RESULTS

There were 16 patients with 23 primary small bowel tumors, 27 mesenteric lymph nodes, 36 liver metastases and 2 peritoneal nodules. Carcinoid tumors exhibited brighter AF signals compared to background. AF imaging was superior to both DOTATATE PET and surgeon inspection/palpation in demonstrating small bowel primaries. Utility for metastatic lymph nodes and peritoneal metastases was limited. Superficial liver metastases exhibited brighter fluorescence compared to background on both ICG and AF imaging.

CONCLUSIONS

This is the largest study assessing utility of near-infrared fluorescence imaging in detection of small bowel carcinoids. Our results show promise in the utilization fluorescence imaging to detect occult primary tumors and superficial liver metastases.

Case report: video-assisted thoracoscopic surgery for pulmonary arteriovenous malformation using near-infrared fluorescence with indocyanine green

BACKGROUND

Pulmonary arteriovenous malformation (PAVM) is an abnormal communication between pulmonary vasculatures and has an unclear boundary with surrounding lung tissues. At present, surgeons can only determine its location by preoperative imaging and intraoperative palpation, despite its soft texture. Indocyanine green(ICG), a near-infrared fluorophore, has been demonstrated useful in the accurate identification of vascular tissue. Therefore, we explored its application in PAVM cases.

CASE PRESENTATION

We present two PAVM cases using near-infrared fluorescence (NIF) with 25 mg ICG at 5 mg/ml to achieve intraoperative visualization of the lesion in video-assisted thoracoscopic surgery (VATS). Under the NIF mode, ICG systemic injection led to successive signaling of the anomaly and normal tissues in merely 10 s, which helped us distinguish them efficiently and precisely. A peak signal-to-background ratio of 2.2 confirmed the significant fluorescence difference and excluded interference from carbon dust.

CONCLUSIONS

We are the first to report the use of such an approach in delineating the margin of vascular malformation with high contrast, and this new finding may help minimize the damage to lung function in PAVM treatment. Further exploration and validation are needed to determine its role.

Synthesis and evaluation of curcumin-based near-infrared fluorescent probes for detection of amyloid β peptide in Alzheimer mouse models

The abnormal accumulation of amyloid β protein (Aβ) is one of the most important causes of Alzheimer's disease (AD) and is usually a detecting biomarker. Curcumin and its derivatives have potential Aβ aggregate targeting ability; we synthesized a series of curcumin-based near-infrared fluorescence probes in this study. By characterizing the excitation wavelength and emission wavelength, the imaging characteristics of the investigation in the near-infrared light region were determined; with an increase in the concentration of the probe compounds, the fluorescence intensity showed an upward trend, demonstrating ideal optical characteristics. In vivo, imaging results showed that the synthesized probe compounds could penetrate the blood-brain barrier (BBB) and specifically bind to Aβ in the brain of APP/PS1 mice. Especially for compound 3b, the maximum emission wavelength was around 667 nm, and the fluorescence signal intensity in the brain of the APP/PS1 mice model was more than twice that of the wild control group at 120 min after administration, which could display Aβ pathological changes. The fluorescent probes designed in this study can become an effective tool for early AD diagnosis and visual detection.

Assessment of jejunal interposition perfusion using indocyanine green

INTRODUCTION

Jejunal interposition (JI) is an option for oesophageal replacement in children; ensuring good graft perfusion is essential. We report three cases where Indocyanine Green (ICG) with Near-Infrared Fluorescence (NIRF) was used to assess perfusion during graft selection, passage into the chest and anastomotic assessment. This extra assessment may reduce risk of anastomotic leak and/or stricture.

METHODS

We describe the technique and salient features of all patients who have undergone ICG/NIRF-assisted JI in our centre. Patient demographics, indications for surgery, intra-operative plan, video of NIR perfusion assessment, complications and outcomes were reviewed.

RESULTS

ICG/NIRF was used in three patients (2M:1F) at a dose of 0.2 mg/kg. ICG/NIRF imaging helped select the jejunal graft and confirmed perfusion after division of segmental arteries. Perfusion was assessed before and after passing the graft through the diaphragmatic hiatus and before and after making the oesophago-jejunal anastomosis. Intrathoracic assessment at the end of the procedure confirmed good perfusion of mesentery and intrathoracic bowel. In two patients, the reassurance contributed to successful procedures. In the third patient, graft selection was satisfactory, but borderline perfusion on clinical assessment after passing the graft to the chest, confirmed by ICG/NIRF meant the graft was abandoned.

CONCLUSIONS

ICG/NIRF imaging was feasible and augmented our subjective assessment of graft perfusion, giving greater confidence during graft preparation, movement, and anastomosis. In addition, the imaging helped us abandon one graft. This series demonstrates the feasibility and benefit of ICG/NIR use in JI surgery. Further studies are required to optimise ICG use in this setting.

Pudexacianinium (ASP5354) chloride for ureter visualization in participants undergoing laparoscopic, minimally invasive colorectal surgery

BACKGROUND

Intraoperative ureteral injury, a serious complication of abdominopelvic surgeries, can be avoided through ureter visualization. Near-infrared fluorescence imaging offers real-time anatomical visualization of ureters during surgery. Pudexacianinium (ASP5354) chloride is an indocyanine green derivative under investigation for intraoperative ureter visualization during colorectal or gynecologic surgery in adult and pediatric patients.

METHODS

In this phase 2 study (NCT04238481), adults undergoing laparoscopic colorectal surgery were randomized to receive one intravenous dose of pudexacianinium 0.3 mg, 1.0 mg, or 3.0 mg. The primary endpoint was successful intraoperative ureter visualization, defined as observation of ureter fluorescence 30 min after pudexacianinium administration and at end of surgery. Safety and pharmacokinetics were also assessed.

RESULTS

Participants received pudexacianinium 0.3 mg (n = 3), 1.0 mg (n = 6), or 3.0 mg (n = 3). Most participants were female (n = 10; 83.3%); median age was 54 years (range 24-69) and median BMI was 29.3 kg/m2 (range 18.7-38.1). Successful intraoperative ureter visualization occurred in 2/3, 5/6, and 3/3 participants who received pudexacianinium 0.3 mg, 1.0 mg, or 3.0 mg, respectively. Median intensity values per surgeon assessment were 1 (mild) with the 0.3-mg dose, 2 (moderate) with the 1.0-mg dose, and 3 (strong) with the 3.0-mg dose. A correlation was observed between qualitative (surgeon's recognition/identification of the ureter during surgery) and quantitative (video recordings of the surgeries after study completion) assessment of fluorescence intensity. Two participants experienced serious adverse events, none of which were drug-related toxicities. One adverse event (grade 1 proteinuria) was related to pudexacianinium. Plasma pudexacianinium concentrations were dose-dependent and the mean (± SD) percent excreted into urine during surgery was 22.3% ± 8.0% (0.3-mg dose), 15.6% ± 10.0% (1.0-mg dose), and 39.5% ± 12.4% (3.0-mg dose).

CONCLUSIONS

In this study, 1.0 and 3.0 mg pudexacianinium provided ureteral visualization for the duration of minimally invasive, laparoscopic colorectal procedures and was safe and well tolerated.

A highly sensitive hemicyanine-based near-infrared fluorescence sensor for detecting toxic amyloid aggregates in human serum

The development of an accurate and sensitive sensor for detecting amyloid plaques, which are responsible for many protein disorders like Alzheimer's disease, is crucial for early diagnosis. Recently, there has been a notable increase in the development of fluorescence probes that exhibit emission in the red region (>600 nm), aiming to effectively tackle the challenges encountered when working with complex biological matrices. In the current investigation, a hemicyanine-based probe, called LDS730, has been used for the sensing of amyloid fibrils, which belong to the Near-Infrared Fluorescence (NIRF) family of dyes. NIRF probes provide higher precision in detection, prevent photo-damage, and minimize the autofluorescence of biological specimens. The LDS730 sensor emits in the near-infrared region and shows a 110-fold increase in fluorescence turn-on emission when bound to insulin fibrils, making it a highly sensitive sensor. The sensor has an emission maximum of ~710 nm in a fibril-bound state, which shows a significant red shift along with a Stokes' shift of ~50 nm. The LDS730 sensor also displays excellent performance in the complicated human serum matrix, with a limit of detection (LOD) of 103 nM. Molecular docking calculations suggest that the most likely binding location of LDS730 in the fibrillar structure is the inner channels of amyloid fibrils along its long axis, and the sensor engages in several types of hydrophobic interactions with neighboring amino acid residues of the fibrillar structure. Overall, this new amyloid sensor has great potential for the early detection of amyloid plaques and for improving diagnostic accuracy.

Choledochal cyst

Choledochal cyst (CC) or congenital biliary dilatation, has a skewed distribution with hereditary features that is far more common in East Asian females. CC is usually associated with pancreaticobiliary malunion (PBMU) forming a common channel. CC requires early definitive diagnosis, since there is a risk for malignancy occurring in the CC and/or intrahepatic bile ducts (IHBD). Complete CC excision and Roux-en-Y hepaticoenterostomy is required and can be performed by open or minimally invasive surgery with hepatojejunostomy the recommended procedure of choice. Principles of open surgical intervention form the basis of minimally invasive management with laparoscopy and robotic assistance. Current surgical management is associated with fewer early and late complications, such as hepaticoenterostomy anastomotic leakage, cholangitis, anastomosis stricture, and cholangiocarcinoma. Specific features of CC management at Juntendo include: intraoperative endoscopy of the common channel and IHBD for inspecting and clearing debris to significantly reduce post-operative pancreatitis or stone formation; near infra-red fluorescence with indocyanine green for visualizing tissue planes especially during minimally invasive surgery for CC; and a classification system for CC based on PBMU that overcomes inconsistencies between existing classification systems and clinical presentation.

Near-infrared fluorescence angiography with indocyanine green for perfusion assessment of DIEP and msTRAM flaps: A Dutch multicenter randomized controlled trial

Background

A common complication after a DIEP flap reconstruction is the occurrence of fat necrosis due to inadequate flap perfusion zones. Intraoperative identification of ischemic zones in the DIEP flap could be optimized using indocyanine green near-infrared fluorescence angiography (ICG-NIR-FA). This randomized controlled trial aims to determine whether intraoperative ICG-NIR-FA for the assessment of DIEP flap perfusion decreases the occurrence of fat necrosis.

Design/methods

This article describes the protocol of a Dutch multicenter randomized controlled clinical trial: the FAFI-trial. Females who are electively scheduled for autologous breast reconstruction using DIEP or muscle-sparing transverse rectus abdominis muscle (msTRAM) flaps are included. A total of 280 patients will be included in a 1:1 ratio between both study arms. In the intervention arm, the intraoperative assessment of flap perfusion will be based on both regular clinical parameters and ICG-NIR-FA. The control arm consists of flap perfusion evaluation only through the regular clinical parameters, while ICG-NIR-FA images are obtained during surgery for which the surgeon is blinded. The main study endpoint is the difference in percentage of clinically relevant fat necrosis between both study arms, evaluated two weeks and three months after reconstruction.

Conclusion

The FAFI-trial, a Dutch multicenter randomized controlled clinical trial, aims to investigate the clinical added value of intraoperative use of standardized ICG-NIR-FA for assessment of DIEP/msTRAM flap perfusion in the reduction of fat necrosis.

Clinical trial registration number

NCT05507710; NL 68623.058.18.

In vivo near-infrared fluorescence imaging of gastric cancer in an MKN-45 gastric cancer xenograft mouse model using intraoperative ureteral identification agent ASP5354

Accurate intraoperative identification of gastric cancer lesions and determination of the extent of resection are important for curability and function preservation. This study aimed to investigate the potential of the near-infrared fluorescence (NIRF) imaging agent ASP5354 for in vivo fluorescence imaging of gastric cancer. The capability of ASP5354 was evaluated using an MKN-45 human gastric cancer xenograft mouse model. A single dose of ASP5354 was intravenously administered to the mice at a concentration of 120 nmol (0.37 mg)/kg body weight. In vivo NIRF images of the mouse backs were obtained using an NIRF camera system. Moreover, the cancer tissues were dissected, and the NIRF intensity in the tissue sections was measured using the NIRF camera system. ASP5354 uptake in MKN-45 cells was assessed in vitro using the NIRF microscope. The NIRF signal of ASP5354 was selectively detected in gastric cancer tissues immediately after the intravenous administration of ASP5354. The cancer tissues emitted stronger NIRF signals than adjacent normal tissues. The difference in the NIRF intensity between the normal and cancer tissues was clearly observed at the boundary between them in the macrolevel NIRF images. Cancer tissues can be distinguished from normal tissues based on the measurement of the NIRF of ASP5354, using an NIRF camera system. ASP5354 is a promising agent for NIRF imaging of gastric cancer tissues.

Intraoperative angiography of the neurovascular bundle using indocyanine green and near-infrared fluorescence improves anatomical dissection during robot-assisted radical prostatectomy: initial clinical experience

Landmark artery identification in the neurovascular bundle (NVB) is important for nerve-sparing in radical prostatectomy. We aimed to investigate intraoperative angiography using indocyanine green and near-infrared fluorescence (ICG-NIRF) during robot-assisted radical prostatectomy (RARP) to identify the NVB, visualise vascularisation and haemostasis, and preserve erectile function. Our retrospective, unicentric study was performed in consecutive localised prostate cancer RARP patients (stage T1/T2, prostate-specific antigen < 10 ng/ml) who underwent ICG-NIRF angiography in France (2016-2021). When ready to dissect the NVB, the anaesthesiologist intravenously injected ICG (3 ml); the surgeon used alternating standard light or fluorescence to optimise NVB visualisation and facilitate microdissection. Primary outcomes: safety and feasibility of ICG-NIRF. Secondary outcomes: functional erectile dysfunction (Sexual Health Inventory for Men (SHIM) questionnaire) over 9 months, proportion of bilateral NVBs identified, ICG-related complications. Standard descriptive statistics were used; t test determined the significance of changes in SHIM scores versus baseline. Ninety-one patients received intraoperative angiography. The NVB was identified in all cases, without difficulties. No ICG-related complications or allergies were observed. There was no significant difference in the SHIM score at 9 months compared with baseline (p = 0.331), and erectile dysfunction returned to baseline levels in almost all patients. Intraoperative, real-time ICG-NIRF angiography is simple, non-invasive, and improves identification of key anatomical landmarks to optimise micropreservation of the NVB during RARP and preserve erectile function. Larger clinical studies should confirm preliminary results.

Near-infrared fluorescence-assisted thoracoscopic diverticulectomy of esophageal diverticulum: a case report

BACKGROUND

Esophageal diverticulum is a rare condition that requires treatment only when symptoms are present. Surgery has been considered to be the only curative option for symptomatic cases. The most popular procedure is diverticulectomy. Clear and intact exposure of the diverticulum's neck is the basis for safe and effective diverticulectomy.

CASE PRESENTATION

We herein report a case of a 57 year-old woman with an epiphrenic diverticulum. VATS diverticulectomy was scheduled. To better identify the diverticulum neck, we injected indocyanine green (ICG) into the diverticulum through the endoscopic channel, and the diverticulum wall and neck were clearly visible under near-infrared (NIR) fluorescence. With the help of this method, diverticulectomy was successfully performed.

CONCLUSION

This case shows that NIR fluorescence with ICG is safe, simple and reliable and can be used for diverticulectomy.

Tumor lesion detection in patients with cervical cancer by indocyanine green near-infrared imaging

PURPOSE

To investigate the feasibility and accuracy of near-infrared fluorescence (NIRF) imaging for detecting the extent of tumor invasion in cervical cancer using indocyanine green (ICG).

METHODS

We enrolled 51 patients who were diagnosed with cervical cancer with FIGO stage IB1-IIA2 disease. Patients were administered indocyanine green (ICG) at a dose of 5 mg/kg 24 h prior to surgery. A customized near-infrared fluorescence (NIRF) imaging system was used to identify the extent of tumor invasion when radical hysterectomy specimens were harvested. The relationship between tumor fluorescence intensity and clinicopathological characteristics was analyzed.

RESULTS

Of the 51 enrolled patients, 3 patients did not have residual tumors after cervical conization, and tumor lesions were identified by NIRF imaging in all the remaining 48 patients. The results of NIRF imaging were in agreement with the postoperative pathological findings in 95.8% of the patients with stromal invasion, 100% of those with surgical margin invasion, 100% of those with parametrial tumor involvement, and 100% of patients with uterine corpus invasion. The mean signal-to-background ratio (SBR) of the cervical tumors was 2.91 ± 1.64, and the SBR was independent of clinicopathological characteristics. Fluorescence microscopy confirmed that ICG fluorescence was present in the tumor nests.

CONCLUSIONS

NIRF imaging enables objective, accurate, and safe identification of tumor invasion during cervical cancer surgery.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT04224467.

Synthesis, Structure and Near Infrared Fluorescence Property of a New Nd-MOF Based on a Triangular Benzylamine Ligand

A new 3D metal-organic framework (Nd-MOF) {[Nd₂L₂]·2NH₂(CH₃)₂·3H₂O} was successfully established via a solvothermal method with Nd³⁺ ion and 5-(bis(4-carboxybenzyl) amino)-isophthalicacid (H₄L), and has also been characterized by X-ray diffraction, powder X-ray diffraction (PXRD), IR and photoluminescence(PL)spectrum. The neodymium ions are free of coordinated solvents, and the Nd-MOF exhibits strong near-infrared (NIR) fluorescence. Besides, Its NIR fluorescence property shows low temperature resistance, which is favorable for being used in the low temperature environment. Besides, the fluorescence lifetime of Nd-MOF is 6.03 μs, and the quantum yield is 1.2%. The small quantum yield may owe to large energy gap between the T1 of the ligand H₄L and the resonance energy level ⁴F_3/2 of the Nd³⁺ ion, or due to large crystal size of the Nd-MOF.

A ratiometric near-infrared fluorescence/photoacoustic dual-modal probe with strong donor dithienopyrrole for in vivo nitric oxide detection

Integrating the imaging techniques of near-infrared fluorescence (NIRF) and photoacoustic (PA) can make up for each other and provide more useful medical information. Ratiometric imaging activated by disease-associated biomarkers can further augment imaging specificity. However, very few studies have employed the NIRF/PA dual-modal ratiometric imaging to improve the accuracy and specificity of disease diagnosis to date. In this paper, we present the synthesis of a nitric oxide (NO)-activated ratiometric NIRF/PA dual-modal nanoprobe RAPNP for in vivo NO imaging. The ratiometric imaging function was achieved jointly by a NO/acidity-responsive molecule DTP-BTDA and a nonresponsive fluorophore DTP-BBTD. In these fluorophores, the dithienopyrrole (DTP) moiety had strong electron-donating ability and imparted strong intramolecular charge transfer and relatively long emission wavelengths. The BTDA moiety in DTP-BTDA could be rapidly oxidized by NO under weak acidic environments, achieving the NIRF and PA signal activation. By using RAPNP as a contrast agent, we achieved the ratiometric detection of the endogenous NO in inflammatory bowel disease by NIRF/PA dual-modal imaging. This work provides the first case of the NIRF/PA dual-signal ratiometric probe for the real-time detection of NO in vivo.

Highlighting the Undetectable - Fluorescence Molecular Imaging in Gastrointestinal Endoscopy

Flexible high-definition white-light endoscopy is the current gold standard in screening for cancer and its precursor lesions in the gastrointestinal tract. However, miss rates are high, especially in populations at high risk for developing gastrointestinal cancer (e.g., inflammatory bowel disease, Lynch syndrome, or Barrett's esophagus) where lesions tend to be flat and subtle. Fluorescence molecular endoscopy (FME) enables intraluminal visualization of (pre)malignant lesions based on specific biomolecular features rather than morphology by using fluorescently labeled molecular probes that bind to specific molecular targets. This strategy has the potential to serve as a valuable tool for the clinician to improve endoscopic lesion detection and real-time clinical decision-making. This narrative review presents an overview of recent advances in FME, focusing on probe development, techniques, and clinical evidence. Future perspectives will also be addressed, such as the use of FME in patient stratification for targeted therapies and potential alliances with artificial intelligence. KEY MESSAGES: • Fluorescence molecular endoscopy is a relatively new technology that enables safe and real-time endoscopic lesion visualization based on specific molecular features rather than on morphology, thereby adding a layer of information to endoscopy, like in PET-CT imaging. • Recently the transition from preclinical to clinical studies has been made, with promising results regarding enhancing detection of flat and subtle lesions in the colon and esophagus. However, clinical evidence needs to be strengthened by larger patient studies with stratified study designs. • In the future fluorescence molecular endoscopy could serve as a valuable tool in clinical workflows to improve detection in high-risk populations like patients with Barrett's esophagus, Lynch syndrome, and inflammatory bowel syndrome, where flat and subtle lesions tend to be malignant up to five times more often. • Fluorescence molecular endoscopy has the potential to assess therapy responsiveness in vivo for targeted therapies, thereby playing a role in personalizing medicine. • To further reduce high miss rates due to human and technical factors, joint application of artificial intelligence and fluorescence molecular endoscopy are likely to generate added value.

Feasibility and comparison of laparoscopic laser speckle contrast imaging to near-infrared display of indocyanine green in intraoperative tissue blood flow/tissue perfusion in preclinical porcine models

OBJECTIVE

To determine if laser speckle contrast imaging (LSCI) mitigates variations and subjectivity in the use and interpretation of indocyanine green (ICG) fluorescence in the current visualization paradigm of real-time intraoperative tissue blood flow/perfusion in clinically relevant scenarios.

METHODS

De novo laparoscopic imaging form-factor detecting real-time blood flow using LSCI and blood volume by near-infrared fluorescence (NIRF) of ICG was compared to ICG NIRF alone, for dye-less real-time visualization of tissue blood flow/perfusion. Experienced surgeons examined LSCI and ICG in segmentally devascularized intestine, partial gastrectomy, and the renal hilum across six porcine models. Precision and accuracy of identifying demarcating lines of ischemia/perfusion in tissues were determined in blinded subjects with varying levels of surgical experience.

RESULTS

Unlike ICG, LSCI perfusion detection was real time (latency < 150 ms: p < 0.01), repeatable and on-demand without fluorophore injection. Operating surgeons (n = 6) precisely and accurately identified concordant demarcating lines in white light, LSCI, and ICG modes immediately. Blinded subjects (n = 21) demonstrated similar spatial-temporal precision and accuracy with all three modes ≤ 2 min after ICG injection, and discordance in ICG mode at ≥ 5 min in devascularized small intestine (p < 0.0001) and in partial gastrectomy (p < 0.0001).

CONCLUSIONS

Combining LSCI for near real-time blood flow detection with ICG fluorescence for blood volume detection significantly improves precision and accuracy of perfusion detection in tissue locations over time, in real time, and repeatably on-demand than ICG alone.

A hemicyanine-based near-infrared fluorescent probe for vapor-phase hydrazine detection and bioimaging in a complete aqueous media

A novel near-infrared fluorescent probe CyOE based on hemicyanine dye containing acetyl as a recognition site is reported. The probe CyOE shows high selectivity and sensitivity (LOD = 82 nM, 2.58 ppb), as well as good water solubility and quantitative detectability of hydrazine in the concentration range of 0-75 μM (R² = 0.993). Moreover, CyOE has a significant increase in fluorescence at 735 nm with the addition of N₂H₄, which provides a rapid, colorimetric and gas-phase detection method for N₂H₄ in both aqueous solution and real water samples. In addition, CyOE is successfully utilized to visualize hydrazine in cells with low cytotoxicity and high cell permeability.

A novel ratiometric sensor prepared based aggregation-induced emission for ultrafast detection of SO2 derivatives in food samples and living cells

As one of the gaseous signaling molecules, aberrant levels of SO₂ are usually associated with many diseases. it is of great significance to develop sensitive methods for detection SO₂ on real. In this paper, a D-π-A near-infrared aggregation-induced fluorescent probe (DPA-CN) was built using diphenylamino-4-benzaldehyde and malononitrile for sensing SO₂. The DPA-CN exhibit AIE characterization that can quickly recognize SO₂ via the Michael addition mechanism. The DPA-CN displayed emission blue drift from 650 nm to 560 nm after adding SO₂, thereby realizing rapid and sensitive colorimetric detection of SO₂. The mechanism for recognition of SO₂ was verified via magnetic resonance imaging ⁽¹H NMR), electrospray ionization mass spectrometry (ESI-MS), scanning electron microscopy (SEM) and dynamic light scattering (DLS). The DPA-CN realized rapid and sensitive recognition of SO₂ with high specificity in 10 s within the concentration range of 0-100 μM. The limit of detection (LOD) is as low as 0.31 μM. Owing to its high sensitivity and low toxicity, the DPA-CN can be applied in monitoring of SO₂ in living cells and food analysis. Furthermore, the DPA-CN was used to prepare a visible and ultrafast semiquantitative paper-based SO₂ sensor with low cost and easy operation.

Image-guided surgery with a new tumour-targeting probe improves the identification of positive margins

Background

Given the lack of visual discrepancy between malignant and surrounding normal tissue, current breast conserving surgery (BCS) is associated with a high re-excision rate. Due to the increasing cases of BCS, a novel method of complete tumour removal at the initial surgical resection is critically needed in the operating room to help optimize the surgical procedure and to confirm tumour-free edges.

Methods

We developed a unique near-infrared (NIR) fluorescence imaging probe, ICG-p28, composed of the clinically nontoxic tumour-targeting peptide p28 and the FDA-approved NIR dye indocyanine green (ICG). ICG-p28 was characterized in vitro and evaluated in multiple breast cancer animal models with appropriate control probes. Our experimental approach with multiple-validations and -blinded procedures was designed to determine whether ICG-p28 can accurately identify tumour margins in mimicked intraoperative settings.

Findings

The in vivo kinetics were analysed to optimize settings for potential clinical use. Xenograft tumours stably expressing iRFP as a tumour marker showed significant colocalization with ICG-p28, but not ICG alone. Image-guided surgery with ICG-p28 showed an over 6.6 × 10³-fold reduction in residual normalized tumour DNA at the margin site relative to control approaches (i.e., surgery with ICG or palpation/visible inspection alone), resulting in an improved tumour recurrence rate (92% specificity) in multiple breast cancer animal models independent of the receptor expression status. ICG-p28 allowed accurate identification of tumour cells in the margin to increase the complete resection rate.

Interpretation

Our simple and cost-effective approach has translational potential and offers a new surgical procedure that enables surgeons to intraoperatively identify tumour margins in a real-time, 3D fashion and that notably improves overall outcomes by reducing re-excision rates.

Funding

This work was supported by NIH/ National Institute of Biomedical Imaging and Bioengineering, R01EB023924.

Biotinylated curcumin as a novel chemosensitizer enhances naphthalimide-induced autophagic cell death in breast cancer cells

Achieving selective release of chemical anticancer agents and improving therapeutic efficacy has always been a hot spot in the field of cancer research, yet how to achieve this remains a great challenge. In this work, we constructed a novel chemical anticancer agent (named MCLOP) by introducing naphthalimide into the skeleton of methylene blue (MB). Under the stimulation by cellular hypochlorous acid (HClO) and visible light, selective release of active naphthalimide can be achieved within breast cancer cell lines, the release process of which can be tracked visually using near-infrared fluorescence of MB (685 nm). More importantly, we developed biotinylated curcumin (Cur-Bio) as a new chemosensitizer, which significantly enhanced the ability of MCLOP to induce autophagic cell death of breast cancer cells. This synergistic treatment strategy exhibited an excellent anti-proliferation effect on breast cancer cells in vitro, three-dimensional (3D) cell sphere model, and mouse tumor model in vivo. This work provides a new strategy for the treatment of breast cancer and also opens new opportunities for the efficient treatment of cancer with curcumin-based chemosensitizer.

Design and Validation of Site-Specifically Labeled Single-Domain Antibody-Based Tracers for in Vivo Fluorescence Imaging and Image-Guided Surgery

Near-infrared fluorescence molecular imaging has become an established preclinical technique to investigate molecular processes in vivo and to study novel therapies. Furthermore, fluorescence molecular imaging is gaining significant interest from clinicians as an intra-operative guidance tool. This technique makes use of targeted fluorescent tracers as contrast agents that recognize specific biomarkers expressed at the site of disease. Single-domain antibodies have shown to possess excellent properties for in vivo imaging in comparison to conventional antibodies. In this chapter, we describe a method for site-specific conjugation of a near-infrared fluorophore to single-domain antibodies by exploiting cysteine-maleimide chemistry. As opposed to random conjugation, site-specific conjugation results in a homogenously labeled fluorescent tracer and avoids inference with antigen binding.

Intravascular Fluorescence Molecular Imaging of Atherosclerosis

Optical molecular imaging using near-infrared fluorescence (NIRF) light is an emerging high-resolution imaging approach to image a wide range of molecular and cellular species in vivo. Imaging using NIR wavelengths (650-900 nm) enables deeper photon penetration into tissue and reduced tissue autofluorescence, resulting in higher sensitivity to detect exogenously administered NIR fluorophores (injectable molecular imaging agents). Greater imaging depth of several centimeters is further achievable in the NIR window as blood absorption is as an order of magnitude lower than in the visible range. Furthermore, as optical imaging is routinely performed in the cardiac catheterization laboratory (e.g., optical coherence tomography), intravascular NIRF offers a promising translational approach for clinical coronary and peripheral arterial imaging. To this point, the first human intravascular NIRF imaging study recently demonstrated the ability to detect NIR autofluorescence in patients with coronary atherosclerosis. This study provides a foundation for targeted intravascular NIRF molecular imaging studies in coronary patients. In this chapter, we detail system engineering, imaging agents and translational applications of intravascular NIRF molecular imaging.

Intraoperative detection of parathyroid glands by autofluorescence identification using image-based system: report of 15 cases

Background

A detection of parathyroid glands by the evaluation of their autofluorescence in the near-infrared spectrum is considered as a promising tool in addition to their visual verification. The aim of this study was to evaluate the role of near-infrared autofluorescence application by using two different image-based systems for the identification of parathyroid glands during surgery of thyroid and parathyroid benign and malignant lesions.

Methods

Evaluation of near-infrared autofluorescence was performed in 15 patients by using two different image-based systems equipped with a near-infrared laser camera. Intravenous injection of fluorophore indocyanine green was used for the enhancement of near-infrared autofluorescence signal.

Results

Normal parathyroid glands were identified and mobilized after visual inspection in 12 (80%) patients, which was confirmed by near-infrared autofluorescence evaluation. Confident recognition of parathyroid glands by near-infrared autofluorescence signal and their subsequent distinction from lymph nodes was achieved in two (13%) patients with prior surgery for papillary thyroid carcinoma. In one (7%) case, parathyroid gland was identified as fragments of tissue within the postoperative scarring area by near-infrared autofluorescence evaluation, but not by visual inspection. A less intensive near-infrared autofluorescence signal was detected in the parathyroid gland owing to unintentional excision in one (7%) case. Better signal intensity from parathyroid glands was noticed after changes of the near-infrared camera in Fluobeam 800 image-based system in position to an angle of approximately 45–65° in relation to area of interest in all cases as compared with holding straight on the parathyroid gland. Fluobeam LX demonstrated a good near-infrared autofluorescence signal without any specific changes in the camera angle. Thyroid carcinoma demonstrated low-intensity signal in the case of invasion to thyroid capsule. No fluorescent signal was identified from metastatic, or from normal, lymph nodes.

Conclusions

The application of near-infrared autofluorescence imaging is considered as a useful, but additional, tool for the visual assessment of parathyroid gland in the case of primary neck exploration. The utility of near-infrared autofluorescence imaging for parathyroid detection is increased in the case of repeated surgical intervention owing to increased risk of unintentional parathyroid removal as well as for discrimination of parathyroids from the lymph nodes in cases of thyroid malignancy.

ATP-responsive near-infrared fluorescence MOF nanoprobe for the controlled release of anticancer drug

A near-infrared (NIR) fluorescence nanoprobe named RhI-DOX@ZIF-90 has been synthesized by wrapping the guest molecule (RhI and DOX) into ZIF-90 framework. The nanoprobe itself is non-fluorescent and the drug (DOX) is inactive. Upon the addition of ATP, the structure of RhI-DOX@ZIF-90 is degraded. The fluorescence of RhI is recovered and DOX is released. The nanoprobe can detect ATP with high sensitivity and selectivity. There is good linear relationship between the nanoprobe and ATP concentration from 0.25 to 10 mM and the detection limit is 0.10 mM. The nanoprobe has the ability to monitor the change of ATP level in living cells and DOX is released inducing apoptosis of cancer cells. RhI-DOX@ZIF-90 is capable of targeting mitochondria, which provides a basis for improving the efficiency of drug delivery by mitochondrial administration. In particular, the nanoprobe is preferentially accumulated in the tumor sites and detect ATP in tumor mice by fluorescence imaging using near-infrared fluorescence. At the same time, DOX can be released accurately in tumor sites and have good anti-tumor efficiency. So, this nanoprobe is a reliable tool to realize early diagnosis of cancer and improve effect of anticancer drug.

Snapshots of lymphatic pathways in colorectal cancer surgery using near-infrared fluorescence, in vivo and ex vivo

INTRODUCTION

Indocyanine green (ICG) fluorescence imaging has been used for blood flow assessment in anastomoses in the field of colorectal cancer surgery. However, whether ICG fluorescence is related to the presence of cancer cells in the lymph nodes is unclear. We explored the utilization of ICG fluorescence in colorectal cancer surgery.

MATERIALS AND METHODS

ICG was injected into the submucosa around the tumor before radical resection in colorectal cancer patients. Intraoperatively, near-infrared (NIR) fluorescence was used for lymphatic flow visualization. After specimen removal, harvested lymph nodes were classified as positive or negative based on the detection of fluorescence, followed by pathological examination. ICG distribution on a section of each lymph node was examined by fluorescence microscopy.

RESULTS

Overall, 155 patients underwent real-time NIR fluorescence imaging-guided surgery. Altogether, 1,017 lymph nodes were retrieved from these patients. Metastatic lymph nodes were present in 36 (5.8%) of 622 fluorescence-negative lymph nodes, which was significantly higher than 11 (2.8%) of 395 fluorescence-positive lymph nodes (odds ratio: 2.15, P = 0.03). Fluorescence microscopy of metastatic lymph nodes showed that ICG fluorescence was present in the normal structural region but not in the cancerous region of the lymph nodes. Furthermore, ICG fluorescence was observed in all metastatic lymph nodes, except those with cancer cells occupying >90% of the total area.

CONCLUSIONS

ICG fluorescence detected only the normal parts of the lymph node draining from the peritumoral area and not the cancer tissues. This finding is important for developing appropriate strategies for navigation surgery using NIR fluorescence.

β-Naphthothiazolium-based ratiometric fluorescent probe with ideal pKa for pH imaging in mitochondria of living cells

The weakly alkaline microenvironment (pH ~8.0) in mitochondria plays a vital role in maintaining its morphology and function. Thus monitoring mitochondrial pH (pH_mito) is of great significance. Herein, a ratiometric fluorescent probe (ENBT) for pHmito imaging in mitochondria of living cells is reported. pH variation closely correlates to intramolecular charge transfer (ICT) from naphthol to β-naphthothiazolium. ENBT exhibits a remarkable decrease on ratiometric fluorescence at λ_em1/λ_em2 = F₅₉₅/F₇₀₀ in response to pH variation within 6.30-9.29. In addition, ENBT has an ideal pKa value of 7.94 ± 0.08, which is advantageous in accurate sensing of pH_mito. Moreover, ENBT has a Stokes shift of >150 nm, which effectively eliminates the potential interference from the excitation irradiation. ENBT shows excellent capability for specific staining of mitochondria with low cytotoxicity, which is most suitable for pH_mito imaging in live cells. The probe was applied for monitoring pH_mito variation in mitochondria of live cells caused by H₂O₂, NAC (N-Acetyl-l-cysteine), NH₄Cl, carbonyl cyanide m-chlorophenyl hydrazone (CCCP) and lactate/pyruvate. The morphological alterations of mitochondria in living cells after treatment by CCCP were further evaluated.

Use of a Novel Fluorescent Catheter to Locate the Ureters during Total Laparoscopic Hysterectomy

Ureteral injury can occur during total laparoscopic hysterectomy. This report documents our experience in using the near-infrared ray catheter (NIRC), a newly developed fluorescent ureteral catheter made of material that contains a fluorescent dye to improve visualization of the ureters. We have used the device in 3 patients between 40 and 50 years of age (mean, 46.3 ± 4.5 years) undergoing total laparoscopic hysterectomy and bilateral salpingectomy for uterine myomas. The time of catheter insertion ranged from 4 minutes and 9 seconds to 10 minutes and 57 seconds. A number of intraoperative procedures were performed near the ureters, namely, identification and ligation of the uterine arteries, dissection of the cardinal ligament, incision of the vaginal canal, and suturing of the vaginal stump. The abovementioned fluorescent ureteral catheter appears green on a monitor when illuminated by near-infrared light, and this facilitated real-time confirmation of the ureter positions, increasing surgical safety. The patients were followed up for 6 months postoperatively, and no urinary tract infection or injury was found. Prophylactic use of the fluorescent ureteral catheter may improve visualization of the ureters in patients considered to be at high risk of ureteral injury, such as those expected to exhibit ureteral deviation due to severe adhesions or an enlarged uterus and when the surgeon has little experience in laparoscopic surgery.

Nanoplatform based on GSH-responsive mesoporous silica nanoparticles for cancer therapy and mitochondrial targeted imaging

Mitochondria, as the energy factory of most cells, are not only responsible for the generation of adenosine triphosphoric acid (ATP) but also essential targets for therapy and diagnosis of various diseases, especially cancer. The safe and potential nanoplatform which can deliver various therapeutic agents to cancer cells and mitochondrial targeted imaging is urgently required. Herein, Au nanoparticles (AuNPs), mesoporous silica nanoparticles (MSN), cationic ligand (triphenylphosphine (TPP)), doxorubicin (DOX), and carbon nanodots (CDs) were utilized to fabricate mitochondrial targeting drug delivery system (denoted as CDs(DOX)@MSN-TPP@AuNPs). Since AuNPs, as the gatekeepers, can be etched by intracellular glutathione (GSH) via ligand exchange induced etching process, DOX can be released into cells in a GSH-dependent manner which results in the superior GSH-modulated tumor inhibition activity. Moreover, after etching by GSH, the CDs(DOX)@MSN-TPP@AuNPs can serve as promising fluorescent probe (λ_ex = 633 nm, λ_em = 650 nm) for targeted imaging of mitochondria in living cells with near-infrared fluorescence. The induction of apoptosis derived from the membrane depolarization of mitochondria is the primary anti-tumor route of CDs(DOX)@MSN-TPP@AuNPs. As a kind of GSH-responsive mitochondrial targeting nanoplatform, it holds great promising for effective cancer therapy and mitochondrial targeted imaging. The mitochondrial targeting drug delivery system was fabricated by AuNPs, MSN, TPP, and CDs. The nanoplatform can realize redox-responsive drug delivery and targeted imaging of mitochondria in living cells to improve the therapeutic efficiency and security.

Near-infrared fluorescence-guided resection of micrometastases derived from esophageal squamous cell carcinoma using a c-Met-targeted probe in a preclinical xenograft model

The postoperative survival of esophageal squamous cell carcinoma (eSCC) is notably hindered by cancer recurrence due to difficulty in identifying occult metastases. Cellular mesenchymal-epithelial transition factor (c-Met), which is highly expressed in different cancers, including eSCC, has become a target for the development of imaging probes and therapeutic antibodies. In this study, we synthesized an optical probe (SHRmAb-IR800) containing a near-infrared fluorescence (NIRF) dye and c-Met antibody, which may help in NIRF-guided resection of micrometastases derived from eSCC. Cellular uptake of SHRmAb-IR800 was assessed by flow cytometry and confocal microscopy. In vivo accumulation of SHRmAb-IR800 and the potential application of NIRF-guided surgery were evaluated in eSCC xenograft tumor models. c-Met expression in human eSCC samples and lymph node metastases (LNMs) was analyzed via immunohistochemistry (IHC). Cellular accumulation of SHRmAb-IR800 was higher in c-Met-positive EC109 eSCC cells than in c-Met-negative A2780 cells. Infusion of SHRmAb-IR800 produced higher fluorescence intensity and a higher tumor-to-background ratio (TBR) than the control probe in EC109 subcutaneous tumors (P < 0.05). The TBRs of orthotopic EC109 tumors and LNMs were 3.01 ± 0.17 and 2.77 ± 0.56, respectively. The sensitivity and specificity of NIRF-guided resection of metastases derived from orthotopic cancers were 92.00% and 89.74%, respectively. IHC results demonstrated positive staining in 97.64% (124/127) of eSCC samples and 91.67% (55/60) of LNMs. Notably, increased c-Met expression was observed in LNMs compared to normal lymph nodes (P < 0.0001). Taken together, the results of this study indicated that SHRmAb-IR800 facilitated the resection of micrometastases of eSCC in the xenograft tumor model. This c-Met-targeted probe possesses translational potential in NIRF-guided surgery due to the high positive rate of c-Met protein in human eSCCs.

Photodynamic theranostics of central lung cancer: Present state and future prospects

Endobronchial photodynamic therapy (PDT) in central lung cancer (CLC) shows feasibility even in late stage disease. Our experience with chlorin e6 based photosensitizers (PS), including in combination with medical cancer treatment, demonstrated regression of tumor lesions of the trachea and bronchi in 94 % of patients with central NSCLC. It is possible to increase the efficiency of the treatment and achieve its personalization by using fluorescent bronchoscopes, which provide fluorescence guided PDT - photodynamic theranostics (PT). PT allows to clarify localization the area of treatment due to visualization of tumor foci which are invisible in white light, to carry out targeted irradiation and at the same time to monitor its effectiveness using the effects of bleaching/flare-up of PS. PT prospects are associated with the transition to the near-infrared (NIR) region, which makes possible to increase the depth of light penetration. The first experiments using the combined NIR/visible PT system showed the possibility of detecting tumor sites using the OS-BPT method (On-Site Bronchoscopic Photodynamic Theranostics), which consists in NIR visualization of tumor when indocyanine green (ICG) is injected directly during examination in a minimal dose. This allows the technology to be used for CLC screening in the future. Further progress of endobronchial PT will be determined by the development of clinically available devices and new NIR PSs with targeted properties, high singlet oxygen yield and fluorescence.

A near-infrared fluorogenic probe with fast response for detecting sodium dithionite in living cells

Developing a reliable fluorescence probe is crucial for accurately monitoring sodium dithionite (Na₂S₂O₄, SDT) in biosystems, but the current reported azo-based ones suffers from short excitation/emission wavelengths and relative slow response speed. To address this issue, we herein present a novel near-infrared emissive fluorescence probe for SDT, namely DCM-MQ, consisting of a dicyanomethylene-benzopyran fluorogenic reporter and a 1-methylquinolinium as recognition moiety. On the basis of the specific reduction mechanism, DCM-MQ exhibited a rapid colorimetric and fluorescent recognition for SDT (less than 3 s) with large Stokes shift (112 nm) and high sensitivity (detection limit was 19 nM). The fluorescence imaging results demonstrate that DCM-MQ is competent for monitoring SDT in living systems.

A dual-modal PET/near infrared fluorescent nanotag for long-term immune cell tracking

Adoptive cell transfer of targeted chimeric antigen receptor (CAR) T cells has emerged as a highly promising cancer therapy. The pharmacodynamic action or CAR T cells is closely related to their pharmacokinetic profile; because of this as well as the risk of non-specific action, it is important to monitor their biodistribution and fate following infusion. To this end, we developed a dual-modal PET/near infrared fluorescent (NIRF) nanoparticle-based imaging agent for non-genomic labeling of human CAR T cells. Since the PET/NIRF nanoparticles did not affect cell viability or cytotoxic functionality and enabled long-term whole-body CAR T cell tracking using PET and NIRF in an ovarian peritoneal carcinomatosis model, this platform is a viable imaging technology to be applied in other cancer models.

The Clinical Value of Fluorescent Lymphography with Indocyanine Green During Robotic Surgery for Gastric Cancer: a Matched Cohort Study

BACKGROUND

Near-infrared (NIR) fluorescence imaging with indocyanine green (ICG) has been recently introduced for lymphatic mapping in several tumors. We aimed at investigating whether this technology may improve the intraoperative visualization of lymph nodes during robotic gastrectomy for gastric cancer.

METHODS

Between June 2014 and June 2018, a total of 94 patients underwent robotic gastrectomy with D2 lymph node dissection for gastric cancer. In 37 patients, ICG was injected endoscopically into the submucosal layer around the tumor the day before surgery. After propensity score matching, the results of these 37 patients were compared with the results of 37 control patients who had undergone robotic gastrectomy without ICG injection.

RESULTS

Among the 37 patients within the ICG group, no adverse events related to ICG injection or intraoperative NIR imaging occurred. After completion of D2 lymph node dissection, no residual fluorescent lymph nodes were left in the surgical field. A mean of 19.4 ± 14.7 fluorescent lymph nodes was identified per patient. The mean total number of harvested lymph nodes was significantly higher in the ICG group than in the control group (50.8 vs 40.1, P = 0.03). In the ICG group, 23 patients had metastatic lymph nodes. The accuracy, sensitivity, and specificity of ICG fluorescence for metastatic lymph nodes were 62.2%, 52.6%, and 63.0%, respectively.

CONCLUSION

Our study indicates that NIR imaging with ICG may provide additional node detection during robotic surgery for gastric cancer. Unfortunately, this technique failed to show good selectivity for metastatic lymph nodes.

Minimally invasive photothermal ablation assisted by laparoscopy as an effective preoperative neoadjuvant treatment for orthotopic hepatocellular carcinoma

Nanoparticle-based photothermal ablation (PTA) has been intensively investigated recently. However, the poor biocompatibility of most PTA agents and potential long-term toxicity obstruct their clinical translation. Meanwhile, previous PTA studies are limited to surface tumors because of insufficient light penetration depth of near-infrared (NIR) light for deep abdominal tumors. Therefore, minimally invasive PTA combined with biocompatible agents may pave a promising way to treat deep orthotopic hepatocellular carcinoma (HCC). Herein, a multifunctional agent based on superparamagnetic iron oxide (SPIO) and new indocyanine green (IR820) was constructed with good biocompatibility. Outstanding fluorescence, photoacoustic and magnetic resonance imaging capabilities were observed in vitro. Additionally, in vivo results indicated that early-stage HCC (diameter less than 2 mm) could be effectively detected by this agent. Furthermore, for the first time, we developed minimally invasive laparoscopic-assisted photothermal ablation (L-A PTA) method coupled with this agent to completely ablate orthotopic HCC in nude mice model, neither recurrences nor obvious side effects were observed during the experiments. Remarkable shrinkage of primary tumor and disappearance of intrahepatic metastasis were also observed. In summary, minimally invasive L-A PTA is an effective preoperative neoadjuvant treatment for HCC.

Simultaneous multipurpose fluorescence imaging with IRDye® 800BK during laparoscopic surgery

BACKGROUND

IRDye® 800BK is a fluorophore, currently undergoing clinical translation, which has both biliary and renal clearance. To date, there is no description of a fluorophore, which can be simultaneously used for non-invasive, near-infrared fluorescence-based (NIRF) visualization of different structures and perfusion evaluation. The purpose of this study was to evaluate IRDye® 800BK for the simultaneous assessment of bowel perfusion, lymphography, ureter and bile duct delineation.

METHODS

Six pigs received a 0.15 mg/kg dye as a single bolus intravenous injection (IV). With the FLER (fluorescence-based enhanced reality) software, fluorescence intensity (FI) of 5 regions of interest (ROI) in an ischemic bowel loop was measured along with the time to reach the FI peak, and capillary lactate was measured from the same ROI, followed by the assessment of the ureters and bile ducts for a maximal duration of 180 min after dye administration. In 3 animals, the procedure was initiated via gastroscopic injection of a 0.6 mg (1 mg/mL) dye in the gastric submucosa followed by lymphography in a NIRF setting.

RESULTS

Excellent visualization of the ureters and bowel perfusion was obtained under NIRF imaging. Additionally, the bile duct and gastric lymph ducts and nodes were visualized. A positive correlation was found between the time to peak FI in the ischemic bowel loop and the corresponding capillary lactate levels (rho 0.59, p < 0.001).

CONCLUSION

In this study, we successfully demonstrated the simultaneous multipurpose IRDye® 800BK applicability during laparoscopic surgery. This fluorophore has the potential to become a powerful and versatile image-guided surgery tool.