A novel fluorescent probe for the early detection of prostate cancer based on endogenous zinc sensing

Fully Integrated Ultra-thin Intraoperative Micro-imager for Cancer Detection Using Upconverting Nanoparticles

PURPOSE

Intraoperative detection and removal of microscopic residual disease (MRD) remain critical to the outcome of cancer surgeries. Today's minimally invasive surgical procedures require miniaturization and surgical integration of highly sensitive imagers to seamlessly integrate into the modern clinical workflow. However, current intraoperative imagers remain cumbersome and still heavily dependent on large lenses and rigid filters, precluding further miniaturization and integration into surgical tools.

PROCEDURES

We have successfully engineered a chip-scale intraoperative micro-imager array-without optical filters or lenses-integrated with lanthanide-based alloyed upconverting nanoparticles (aUCNPs) to achieve tissue imaging using a single micro-chip. This imaging platform is able to leverage the unique optical properties of aUCNPs (long luminescent lifetime, high-efficiency upconversion, no photobleaching) by utilizing a time-resolved imaging method to acquire images using a 36-by-80-pixel, 2.3 mm [Formula: see text] 4.8 mm silicon-based electronic imager micro-chip, that is, less than 100-µm thin. Each pixel incorporates a novel architecture enabling automated background measurement and cancellation. We have validated the performance, spatial resolution, and the background cancellation scheme of the imaging platform, using resolution test targets and mouse prostate tumor sample intratumorally injected with aUCNPs. To demonstrate the ability to image MRD, or tumor margins, we evaluated the imaging platform in visualizing a single-cell thin section of the injected prostate tumor sample.

RESULTS

Tested on USAF resolution targets, the imager is able to achieve a resolution of 71 µm. We have also demonstrated successful background cancellation, achieving a signal-to-background ratio of 8 when performing ex vivo imaging on aUCNP-injected prostate tumor sample, improved from originally 0.4. The performance of the imaging platform on single-cell layer sections was also evaluated and the sensor achieved a signal-to-background ratio of 4.3 in resolving cell clusters with sizes as low as 200 cells.

CONCLUSION

The imaging system proposed here is a scalable chip-scale ultra-thin alternative for bulky conventional intraoperative imagers. Its novel pixel architecture and background correction scheme enable visualization of microscopic-scale residual disease while remaining completely free of lenses and filters, achieving an ultra-miniaturized form factor-critical for intraoperative settings.

Novel Prostate Cancer Biomarkers: Aetiology, Clinical Performance and Sensing Applications

The review initially provides a short introduction to prostate cancer (PCa) incidence, mortality, and diagnostics. Next, the need for novel biomarkers for PCa diagnostics is briefly discussed. The core of the review provides details about PCa aetiology, alternative biomarkers available for PCa diagnostics besides prostate specific antigen and their biosensing. In particular, low molecular mass biomolecules (ions and metabolites) and high molecular mass biomolecules (proteins, RNA, DNA, glycoproteins, enzymes) are discussed, along with clinical performance parameters.

Carcinoembryonic Antigen Related Cell Adhesion Molecule 6 Promotes Carcinogenesis of Gastric Cancer and Anti-CEACAM6 Fluorescent Probe Can Diagnose the Precancerous Lesions

The diagnosis of precancerous lesions or early gastric cancer (EGC) is very important for patient survival. Molecular imaging is a visualized method that can easily and precisely diagnose tumors. However, there are currently few studies about molecular imaging diagnosis of EGC. Here, we studied the expression of carcinoembryonic antigen related cell adhesion molecule 6 (CEACAM6) in the progression of GC. Then, the regulatory roles of CEACAM6 in GC cells were investigated. Furthermore, both the fluorescent-labeled and near infrared molecular-labeled probes were synthesized, and the diagnostic value of anti-CEACAM6 probes in GC was evaluated in vivo using a GC mice model as well as in vitro using fresh dysplastic gastric mucosa obtained from endoscopic submucosal dissection (ESD) operations. Our study showed that CEACAM6 was over expressed in GC tissues compared to adjacent tissues, and the patients with higher CEACAM6 expression had lower survival time. Moreover, the CEACAM6 expression was higher in the dysplastic gastric mucosa than in the adjacent normal mucosa. CEACAM6 accelerated the growth, proliferation, and invasion of GC cells in the in vitro and in vivo studies. Moreover, up regulated CEACAM6 can induce the expression of proteins related to GC progression. Furthermore, the anti-CEACAM6 probes exhibited good affinity with GC cell lines. The probes can track tumors as well as metastases in the mice model in vivo, and can precisely identify the area of dysplastic gastric mucosa using specimens obtained from ESD operations by wide field fluorescent endoscopy. The surface micro features of the mucosa can also be observed using fluorescent micro endoscopy, and the degree of atypia can be distinguished by both the signal intensity and surface micro morphology. CEACAM6 is a key molecular marker in GC progression, and the anti-CEACAM6 probe-assisted fluorescent endoscopy may be a potential option for the diagnosis of precancerous lesions.

Successive Detection of Zinc Ion and Citrate Using a Schiff Base Chemosensor for Enhanced Prostate Cancer Diagnosis in Biosystems

Sensitive and quantitative detection of prostate cancer (PC) requires a chemosensor with an applicable sensing strategy. A star-shaped Schiff base triaminoguanidine-integrated thiophene fluorophore TAT was rationally designed with nitrogen and sulfur atoms to coordinate with Zn²⁺ as the initial step and to chelate with citrate as the following step. Formation of the complex TAT-Zn²⁺ induced an intramolecular charge transfer and caused a red-shifted, Zn²⁺ concentration-dependent fluorescence at 507 nm. Chelation of TAT-Zn²⁺ with citrate led to an emission band at 692 nm upon an aggregation-induced emission mechanism. The distinctive fluorescence emissions of Zn²⁺ and citrate biomarkers were demonstrated first in on-site paper-based test strips showing gradually enhanced colors at yellow and red channels and second in both in vitro and in vivo by using PC3 cells and BALB/c nude mouse animal models, respectively. The in vitro test confirmed the mitochondria organelle-targeting property of TAT, and the in vivo performance manifested the successful application of the probe in recognizing the prostate cancer. This is the first applicable chemosensor that could be in continuous recognition of dual PC biomarkers Zn²⁺ and citrate in cancer diagnosis with a mitochondria organelle-targeting ability.

A novel tetrapeptide fluorescence sensor for early diagnosis of prostate cancer based on imaging Zn2+ in healthy versus cancerous cells

Zinc as a biomarker can be used to diagnose the early stage prostate cancer, while ZIP1 protein, a zinc transporter is significantly down-regulated in prostate cancer cells. This behavior leads to the apparent alteration of the enrichment ability for zinc between early prostate cancer tissues and healthy tissues. This difference inspires us to develop a novel Zn²⁺ sensor that applies to the clinic diagnosis of early prostate cancer. We designed a tetrapeptide sensor H₂L (Dansyl-Gly-Pro-Trp-Gly-NH₂) according to the photo-induced electron transfer principle (PET), and it performed adequately in Zn²⁺ imaging of prostate cell lines. Based on the assessment of Zn²⁺ enrichment ability, there was distinctly lower Zn²⁺ concentrate in prostate cancer cell lines than healthy prostate epithelial cells. Furthermore, H₂L displayed high sensitivity with a detection limit as low as 49.5 nM, and high specificity for Zn²⁺ detection. Also the low toxicity and the superior cell permeability of H₂L made the imaging of Zn²⁺ ions detection safe and rapid. We expect that H₂L to be a powerful tool for early diagnosis of prostate cancer and a good indicator for the precise resection of cancer tissue during surgery.

Advances of Zinc Signaling Studies in Prostate Cancer

Prostate cancer (PCa) is one of the most common cancers and the second leading cause of cancer-related death among men worldwide. Despite progresses in early diagnosis and therapeutic strategies, prognosis for patients with advanced PCa remains poor. Noteworthily, a unique feature of healthy prostate is its highest level of zinc content among all soft tissues in the human body, which dramatically decreases during prostate tumorigenesis. To date, several reviews have suggested antitumor activities of zinc and its potential as a therapeutic strategy of PCa. However, an overview about the role of zinc and its signaling in PCa is needed. Here, we review literature related to the content, biological function, compounds and clinical application of zinc in PCa. We first summarize zinc content in prostate tissue and sera of PCa patients with their clinical relevance. We then elaborate biological functions of zinc signaling in PCa on three main aspects, including cell proliferation, death and tumor metastasis. Finally, we discuss clinical applications of zinc-containing compounds and proteins involved in PCa signaling pathways. Based on currently available studies, we conclude that zinc plays a tumor suppressive role and can serve as a biomarker in PCa diagnosis and therapies.

An AIE and PET fluorescent probe for effective Zn(ii) detection and imaging in living cells

A sensitive fluorescent probe L for Zn²⁺ with aggregation-induced emission (AIE) properties has been synthesized.

A fluorescent sensor for intracellular Zn2+ based on cylindrical molecular brushes of poly(2-oxazoline) through ion-induced emission

Poly(2-oxazoline) molecular brushes bearing enaminitrile receptors in the side chain ends exhibit good biocompatibility, excellent fluorescent selectivity for Zn²⁺, and possibility in detecting intracellular Zn²⁺.