Universal crRNA Acylation Strategy for Robust Photo-Initiated One-Pot CRISPR-Cas12a Nucleic Acid Diagnostics.

Spatiotemporal regulation of clustered regularly interspaced short palindromic repeats (CRISPR) system is attractive for precise gene editing and accurate molecular diagnosis. Although many efforts have been made, versatile and efficient strategies to control CRISPR system are still desirable. Here, we proposed a universal and accessible acylation strategy to regulate the CRISPR-Cas12a system by efficient acylation of 2'-hydroxyls (2'-OH) on crRNA strand with photolabile agents (PLGs). The introduction of PLGs confers efficient suppression of crRNA function and rapid restoration of CRISPR-Cas12a reaction upon short light exposure regardless of crRNA sequences. Based on this strategy, we constructed a universal PhotO-Initiated CRISPR-Cas12a system for Robust One-pot Testing (POIROT) platform integrated with recombinase polymerase amplification (RPA), which showed two orders of magnitude more sensitive than the conventional one-step assay and comparable to the two-step assay. For clinical sample testing, POIROT achieved high-efficiency detection performance comparable to the gold-standard quantitative PCR (qPCR) in sensitivity and specificity, but faster than the qPCR method. Overall, we believe the proposed strategy will promote the development of many other universal photo-controlled CRISPR technologies for one-pot assay, and even expand applications in the fields of controllable CRISPR-based genomic editing, disease therapy, and cell imaging.

Antibiotic combinations prediction based on machine learning to multicentre clinical data and drug interaction correlation.

BACKGROUND: With increasing antibiotic resistance and regulation, the issue of antibiotic combination has been emphasised. However, antibiotic combination prescribing lacks a rapid identification of feasibility, while its risk of drug interactions is unclear. METHODS: We conducted statistical descriptions on 16 101 antibiotic coprescriptions for inpatients with bacterial infections from 2015 to 2023. By integrating the frequency and effectiveness of prescriptions, we formulated recommendations for the feasibility of antibiotic combinations. Initially, a machine learning algorithm was utilised to optimise grading thresholds and habits for antibiotic combinations. A feedforward neural network (FNN) algorithm was employed to develop antibiotic combination recommendation model (ACRM). To enhance interpretability, we combined sequential methods and DrugBank to explore the correlation between antibiotic combinations and drug interactions. RESULTS: A total of 55 antibiotics, covering 657 empirical clinical antibiotic combinations were used for ACRM construction. Model performance on the test dataset showed AUROCs of 0.589-0.895 for various antibiotic recommendation classes. The ACRM showed satisfactory clinical relevance with 61.54-73.33% prediction accuracy in a new independent retrospective cohort. Antibiotic interaction detection showed that the risk of drug interactions was 29.2% for strongly recommended and 43.5% for not recommended. A positive correlation was identified between the level of clinical recommendation and the risk of drug interactions. CONCLUSIONS: Machine learning modelling of retrospective antibiotic prescriptions habits has the potential to predict antibiotic combination recommendations. The ACRM plays a supporting role in reducing the incidence of drug interactions. Clinicians are encouraged to adopt such systems to improve the management of antibiotic usage and medication safety.

Tight focusing through scattering media via a Bessel-basis transmission matrix.

The transmission matrix (TM) is a powerful tool for focusing light through scattering media. Here, we demonstrate a Bessel-basis TM that enables tight focusing through the scattering media and reduces the full width at half maximum of the focus by 23% on average, as compared to the normally used Hadamard-basis TM. To measure the Bessel-basis TM, we establish a common-path inter-mode interferometer (IMI), which can fully utilize the pixels of the spatial light modulator, leading to an enhancement in the peak-to-background intensity ratio (PBR) of the focus. Experimental results suggest that the Bessel-basis TM can achieve a tighter focus behind the scattering media, and the PBR of the focus obtained by the IMI is around 14.3% higher than that achieved using the normal peripheral reference interferometry.

A single mitochondria-targetable fluorescent probe for visualizing cysteine and glutathione in ferroptosis of myocardial ischemia/reperfusion injury.

Ferroptosis plays an important role in the early stage of myocardial ischemia/reperfusion (MI/R) injury, which is closely associated with the antioxidant damage of mitochondrial cysteine (Cys)/glutathione (GSH)/glutathione peroxidase 4 (GPX4) axis. Visualization of Cys and GSH in mitochondria is meaningful to value ferroptosis and further contributes to understanding and preventing MI/R injury. Herein a mitochondria-targetable thiols fluorescent probe (MTTP) was designed and synthesized based on sulfonyl benzoxadiazole (SBD) chromophore with a triphenylphosphine unit as the mitochondria-targeted functional group. Cys and GSH can be differentiated by MTTP with two distinguishable emission bands (583 nm and 520 nm) through the controllable aromatic substitution-rearrangement reaction. Importantly, MTTP is capable of monitoring ferroptosis and its inhibition by measuring mitochondrial Cys and GSH. MTTP was also employed to non-invasively detect ferroptosis during oxygen and glucose deprivation/reoxygenation (OGD/R)-induced MI/R injury in H9C2 cells. In a word, MTTP provides a visual tool that can simultaneously detect Cys and GSH to monitor ferroptosis processes during MI/R injury, which helps for more deeper understanding of the role of ferroptosis in MI/R injury-related diseases.

Engineering a near-infrared LAP fluorescent probe with high sensitivity and selectivity for surgical resection of liver cancer.

Hepatocellular carcinoma (HCC) is a type of cancer associated with a high rate of mortality and morbidity. In order to achieve precise HCC theranostics, it is important to develop excellent fluorescent probes. However, the existing probes are not sensitive or specific enough to accurately identify HCC margins and contours. For diagnosing HCC and identifying tumors during surgery, it is urgent to engineer highly sensitive and selective fluorescent probes. Liver tumor progression is closely associated with leucine aminopeptidase (LAP) overexpression, a biomarker of liver cancer. Herein, we have rationally designed a NIR fluorescent probe, NLAP, which is specially activated by LAP. The probe exhibited high sensitivity (detection limit = 6.8 mU L-1) and superior affinity (Km = 2.98 µM) for LAP. With this probe, we distinguished cancer cells overexpressing LAP from normal cells and applied it intraoperatively to guide liver tumor excisions. Furthermore, NLAP was employed to successfully detect the LAP of intestinal and splenic metastatic tumors in orthotopic liver tumor mice by "in situ spraying" and good performances were demonstrated.

Advances in Multifunctional Chemotherapeutic Prodrugs for Near-infrared Fluorescence Imaging-guided Therapy.

Conventional chemotherapy (CT) is associated with severe side effects and inducible resistance, making it difficult to meet clinical requirements, forcing the development of new multifunctional prodrugs for precision medicine. In recent decades, researchers and clinicians have focused on developing of multifunctional chemotherapeutic prodrugs with tumor-targeting capability, activatable and traceable chemotherapeutic activity, as a powerful tool to improve theranostic outcomes in cancer treatment. The conjugates of near-infrared (NIR) organic fluorophores and chemotherapy reagents create an exciting avenue for real-time monitoring of drug delivery and distribution, as well as the combination of chemotherapy and photodynamic therapy (PDT). Therefore, there are great opportunities for researchers to conceive and exploit multifunctional prodrugs that can visualize chemo-drugs release and tumor treatment in vivo. In this review, the design strategy and the recent progress of multifunctional organic chemotherapeutic prodrugs for activating NIR fluorescence imaging-guided therapy are described and discussed in detail. Finally, the prospects and challenges of multifunctional chemotherapeutic prodrugs for NIR fluorescence imaging-guided therapy are provided.

Enhancing the Selectivity of Leucine Aminopeptidase Near-Infrared Fluorescent Probes for Assisting in Surgical Tumor Resection.

Selective fluorescence imaging of analytes is a challenge for monitoring diseases as homologues interfere with the imaging agents. Leucine aminopeptidase (LAP), a kind of protease, is related to tumor pathogenesis. The known LAP fluorescent probes based on leucine recognition have limited selectivity. Herein, a selective t-butyl-alanine recognition unit for LAP through the ligand regulation strategy is prepared as a new near-infrared (NIR) fluorescent probe (DCM-LAP) having a large Stokes shift of 214 nm and a high sensitivity with a detection limit of 168 mU/L. DCM-LAP has an enhanced response toward LAP with NIR fluorescence at 656 nm based on intramolecular charge transfer. The probe is selective without being interfered with by biological enzymes including the aminopeptidase N (APN). DCM-LAP can image LAP activity in living cells. It can also visualize the cell invasion and migration processes. DCM-LAP is employed in the real-time imaging of LAP in tumor-bearing nude mice and guides in the accurate resection of breast tumors. It also distinguishes tumor tissues from normal with a high tumor-to-normal ratio (9.8). The DCM-LAP probe can thus assist in the investigations of LAP-associated clinical disease.

Ultrasensitive CRISPR/Cas13a-Mediated Photoelectrochemical Biosensors for Specific and Direct Assay of miRNA-21.

Sensitive and specific assay of microRNAs (miRNAs) is beneficial to early disease screening. Herein, we for the first time proposed clustered regularly interspaced short palindromic repeats (CRISPR)/Cas13a-mediated photoelectrochemical biosensors for the direct assay of miRNA-21. In this study, compared with traditional nucleic acid-based signal amplification strategies, the CRISPR/Cas13a system can greatly improve the specificity and sensitivity of target determination due to its accurate recognition and high-efficient trans-cleavage capability without complex nucleic acid sequence design. Moreover, compared with the CRISPR/Cas12a-based biosensing platform, the developed CRISPR/Cas13a-mediated biosensor can directly detect RNA targets without signal transduction from RNA to DNA, thereby avoiding signal leakage and distortion. Generally, the proposed biosensor reveals excellent analysis capability with a wider linear range from 1 fM to 5 nM and a lower detection limit of 1 fM. Additionally, it also shows satisfactory stability in the detection of human serum samples and cell lysates, manifesting that it has great application prospects in the areas of early disease diagnosis and biomedical research.

Detection of simple proteins by direct surface-enhanced Raman scattering based on the Hofmeister ion-specific effect.

Surface-enhanced Raman scattering (SERS) spectroscopy has unique advantages in detecting biomolecules, but label-free determination of proteins with low scattering cross-sections remains challenging. In this study, such proteins' SERS signals have been optimized using the Hofmeister effect between protein molecules and CsI solution at physiological concentrations (A 100 mmol/L Cesium iodide, CsI). Cs+ as chaotro cation ion has a complex interaction mechanism with protein, can not only deprive hydrated water molecules on the surface of protein but also penetrate into the hydrophobic interior of protein. In addition to the above advantages, I- in excess CsI solution with appropriate concentration can removes the interference of citric acid-based impurities on the surface of silver nanoparticles, and Cs+ in excess CsI solution attracts the aggregation of negatively charged silver nanoparticles and cause local electromagnetic field enhancement to achieve high sensitivity in protein detection. This has been combined with principal component analysis to perform a comprehensive analysis of several proteins. Molecular dynamics simulations have been performed to study the mechanism of interaction between CsI and proteins. In addition, the vibrational peak of water has been used as an internal standard to quantify the protein content, and a good linear relationship between peak intensity and concentration was obtained.

Alternate-day fasting for the protection of cognitive impairment in c57BL/6J mice following whole-brain radiotherapy.

NLRP3 inflammasome activation is implicated in irradiation-induced cognitive dysfunction. Alternate-day fasting (ADF) has been demonstrated to improve neuroinflammation as a non-pharmacological intervention. However, the exact mechanism and the anti-inflammatory effect in irradiation-induced cognitive dysfunction still need further in-depth study. The present study examined the effects of eight-week ADF on the cognitive functions of mice as well as inflammasome-mediated hippocampal neuronal loss following irradiation in mouse models of irradiation-induced cognitive deficits using seven-week-old male C57BL/6J mice. The behavioral results of novel place recognition and object recognition tasks revealed that ADF ameliorated cognitive functions in irradiation-induced cognitive dysfunction mice. ADF inhibited the expression of components of the NLRP3 inflammasome (NLRP3, ASC, and Cl.caspase-1), the downstream inflammatory factor (IL-1ß and IL-18), and apoptosis-related proteins (caspase-3) via western blotting. Furthermore, an increased number of neurons and activated astrocytes were observed in the hippocampus using immunohistochemistry and Sholl analysis, which was jointly confirmed by western blotting. According to our study, this is the first time we found that ADF improved cognitive dysfunction induced by irradiation, and the anti-inflammatory effect of ADF could be due to inhibition in NLRP3-mediated hippocampal neuronal loss by suppressing astrocyte activation.

The effects of dietary patterns and food groups on symptomatic osteoarthritis: A systematic review.

AIM: To systematically review current literature to determine the association between symptomatic osteoarthritis and dietary patterns, diet quality and food groups in adults aged ≥45 years. METHODS: The review was registered on PROSPERO (CRD42021270891). Cochrane Central Library, Cumulative Index of Nursing and Allied Health Literature, Embase, Medline and Web of Science databases were searched. A total of 3816 records were identified. Eligible articles involved populations aged ≥45 years with symptomatic osteoarthritis, assessing dietary patterns, diet quality or food groups, with pain in joints as outcomes. The Joanna Briggs Institute Critical Appraisal Checklists were used for quality assessment. Grading of Recommendations, Assessment, Development and Evaluation was used to assess the certainty of evidence. RESULTS: Six cohort studies were included. The Prudent dietary pattern and the Mediterranean dietary pattern reduced the progression of osteoarthritis symptoms. The Western dietary pattern increased symptomatic osteoarthritis progression. Increased total fibre consumption reduced symptomatic osteoarthritis progression and pain worsening, but the effects of fibre from each food group were inconclusive. Diet with high inflammatory potential increased risk of new onset symptomatic osteoarthritis, but the effects of overall diet quality were inconclusive. CONCLUSIONS: The Prudent dietary pattern showed the highest protection on symptomatic osteoarthritis in adults aged 45 years and over. The body of evidence is limited, suggesting that further research is needed to corroborate the estimated effect at a high certainty of evidence, and to incorporate previously unstudied dietary patterns and food groups. Identifying the most beneficial dietary pattern may inform future guidelines for reducing symptomatic osteoarthritis in middle aged and older adults.

Synthesis and application of novel N, Si-carbon dots for the ratiometric fluorescent monitoring of the antibiotic balofloxacin in tablets and serum.

A ratiometric fluorescent probe with blue-emission fluorescence based on N, Si-doped carbon dots (N, Si-CDs) for the detection of balofloxacin (BLFX) was synthesized by simple one-pot hydrothermal carbonization using methotrexate and 3-aminopropyltriethoxysilane (APTES) as carbon materials. The obtained N, Si-CDs showed dual-emission band fluorescence characterization at 374 nm and 466 nm. Furthermore, the synthesized N, Si-CD probe exhibited evidence of ratiometric fluorescence emission characteristics (F 466/F 374) toward BLFX along with a decrease in fluorescence intensity at 374 nm and an increase in fluorescence intensity at 466 nm. Based on this probe, a highly sensitive and fast detection method for the analysis of BLFX has been established with a linear range of 1-60 µM and a low detection limit of 0.1874 µM, as well as a rapid response time of 5.0 s. The developed assay has also been successfully applied for the detection of BLFX in tablets and rat serum.

PD-1 inhibitors plus lenvatinib versus PD-1 inhibitors plus regorafenib in patients with advanced hepatocellular carcinoma after failure of sorafenib.

Background: Lenvatinib, regorafenib and anti-programmed cell death protein-1 (PD-1) immunotherapy have shown promising clinical outcomes in patients with advanced hepatocellular carcinoma (HCC) after sorafenib failure, respectively. However, the combination of the two treatments has not been reported. We compared the efficacy of PD-1 inhibitors with lenvatinib (PL) and PD-1 inhibitors plus regorafenib (PR) in patients with advanced HCC in this study. Methods: We conducted a retrospective study of advanced HCC patients who undergone PD-1 inhibitors combined with lenvatinib or regorafenib after failure of sorafenib at Second Affiliated Hospital of Nanchang University from July 2018 and December 2020. The overall survival (OS), progression-free survival (PFS), effective rates and treatment-related adverse events (TRAEs) were investigated. Results: In total, 61 patients met the criteria and were included in the present study, and they were divided into the PL group (n = 32) and PR group (n = 29). The overall response rate (ORR) (12.5%vs. 10.3%, respectively; p = 0.557) and disease control rate (DCR) (71.9%vs. 58.6%, respectively; p < 0.207) were higher in the PL group than in the PR group, but there was no statistical difference.Furthermore, median PFS and OS were not significantly different between the two groups in Kaplan-Meier survival analysis (PFS: 5.3 months vs 4.0 months, p = 0.512; OS: 14.1 months vs 13.7 months, p = 0.764 for the PL group vs PR group). The most common treatment-related adverse events (TRAEs) were hand -foot skin reaction (24/61,39.3%), hypertension (20/61,32.8%) and hypothyroidism (13/61,21.3%). The frequent TRAEs (≥Grade 3) during PD-1 inhibitors plus lenvatinib or regorafenib treatment were hand-foot skin reaction (5/29,12.4%), thrombocytopenia (2/29 6.90%) and proteinuria (n =2/32,6.25%). Conclusions: Combination of lenvatinib/regorafenib and PD-1 inhibitors is a promising therapy for HCC patients after sorafenib failure.

Ultraprecise Real-Time Monitoring of Single Cells in Tumors in Response to Metal Ion-Mediated RNA Delivery.

With the deepening of cancer clinical research, miRNAs provide new ideas for molecular diagnosis and treatment of tumors. Improving the molecular delivery efficiency of miRNA is the key to the success of miRNA therapy. We have established self-assembly diagnosis and treatment technologies that can be used to achieve accurate targeting and "cargo" delivery at the cellular level. This technology builds a miRNA (let-7a) delivery system based on metal precursor [Au(III) and Fe(II)]-mediated tumor microenvironmental response to realize the self-assembly of Au&Fe-miRNA complexes for precise real-time imaging of tumor cells and targeted therapy. To accurately measure the changes in reactive oxygen species during complex formation in real time at the single-cell level, we employed small-size nanoscale devices as analytical tools. This study proposes an electrochemical sensor based on carbon fiber electrodes for ultraprecise and multiple monitoring of metal-ion-mediated miRNA delivery systems, precisely realizing targeted tracking of tumors and effective intervention inhibition.

A case report on a child with fracture and dislocation of the upper cervical spine accompanied by spinal cord injury.

RATIONALE: This study describes an 8-year-old boy with a C2 fracture and dislocation with a left C2-C3 articular process interlocking and spinal cord injury who underwent open reduction and internal fixation using the posterior cervical approach and achieved satisfactory results. PATIENT CONCERNS: An 8-year-old boy underwent an emergency transfer from a previous hospital after a car accident. DIAGNOSES: Axial fracture and dislocation with spinal cord injury (American Spinal Injury Association grade C), traumatic shock, brain contusion, intracranial hemorrhage, mandibular fracture, pulmonary contusion and hemorrhage, left vertebral artery stenosis, and multiple fractures throughout the body. Radiological examination revealed a fracture of the lower edge of the C2 vertebral body, fourth-degree anterior spondylolisthesis of the C2 vertebral body, interlocking of the left C2-C3 articular processes, widening of the C2-C3 vertebral space, and occlusion of the V1 and 2 segments of the left vertebral artery. INTERVENTIONS: The boy was immediately intubated and transferred to the pediatric intensive care unit for rescue treatment. However, the reduction was unsuccessful with 2 weeks of cranial traction. Thus, an open reduction was performed under general anesthesia. One month after the surgery, the boy was discharged from the hospital on foot after rehabilitation treatment. OUTCOMES: The boy was discharged from the hospital 1 month after surgery. At the 8-month follow-up, a radiological examination showed that the corrected C2 vertebral body fracture and dislocation were satisfactorily reduced, and the spinal cord was adequately decompressed. The internal fixation position was also good, and the spinal sequence had recovered well. In summary, except for the muscle strength of the right upper limb, which was slightly worse, the other clinical symptoms were significantly improved. LESSONS: In treating cervical fracture and dislocation with unilateral facet lock, the posterior open reduction of pedicle screw and lateral mass screw internal fixation achieved satisfactory results. Consequently, treating complex cervical spine injuries in children requires an accurate diagnosis and careful treatment strategy.

Roles of m6A modification in neurological diseases. / m6A ä¿®é¥°åœ¨ç¥žç»ç³»ç»Ÿç–¾ç— ä¸­çš„ä½œç”¨.

N6-methyladenosine (m6A) methylation modification is one of the most common epigenetic modifications for eukaryotic mRNA. Under the catalytic regulation of relevant enzymes, m6A participates in the body's pathophysiological processes via mediating RNA transcription, splicing, translation, and decay. In the past, we mainly focused on the regulation of m6A in tumors such as hematological tumors, cervical cancer, breast cancer. In recent years, it has been found that m6A is enriched in mRNAs of neurogenesis, cell cycle, and neuron differentiation. Its regulation in the nervous system is gradually being recognized. When the level of m6A modification and the expression levels of relevant enzyme proteins are changed, it will cause neurological dysfunction and participate in the occurrence and conversion of neurological diseases. Recent studies have found that the m6A modification and its associated enzymes were involved in major depressive disorder, Parkinson's disease, Alzheimer's disease, Fragile X syndrome, amyotrophic lateral sclerosis, and traumatic brain injury, and they also play a key role in the development of neurological diseases and many other neurological diseases. This paper mainly reviewed the recent progress of m6A modification-related enzymes, focusing on the impact of m6A modification and related enzyme-mediated regulation of gene expression on the central nervous system diseases, so as to provide potential targets for the prevention of neurological diseases.

Golgi-Targeting Fluorescent Probe for Monitoring CO-Releasing Molecule-3 In Vitro and In Vivo.

CO-releasing molecule-3 (CORM-3), mainly metal carbonyl compounds, is widely used as experimental tools to deliver CO, a biological "gasotransmitter", in mammalian systems. CORM-3 is also proposed as a potential new antimicrobial agent, which kills bacteria effectively and rapidly in vitro and in animal models. Organelle-targeting therapy, as a highly effective therapeutic strategy with little toxic and side effects, has important research significance and development prospects. Therefore, the development of effective methods for detecting and tracking CORM-3 at the subcellular level has important implications. In this paper, an easily available Golgi-targetable fluorescent probe (Golgi-Nap-CORM-3) was proposed for CORM-3 detection. In the probe Golgi-Nap-CORM-3, the phenyl sulfonamide group was selected as the Golgi-targetable unit, naphthalimide dye was chosen as a fluorophore, and the nitro group was selected as a CORM-3-responsive unit. Golgi-Nap-CORM-3 shows a CORM-3-reponsive increase of fluorescence emission at 520 nm. Using the excellent probe, the change of CORM-3 in HeLa cells, HepG2 cells, and zebrafish is successfully monitored. This study demonstrates very important information for the study of CORM-3 in vivo systems.

A novel fluorescence ratio probe based on dual-emission carbon dots for highly selective and sensitive detection of chlortetracycline and cell imaging.

The novel dual-emission carbon dots (DECDs) for highly selective and sensitive recognition of chlortetracycline (CTC) and cell imaging were synthesized successfully by one-step synthesis. The obtained DECDs possessed two fluorescence peaks (345 nm and 450 nm) and showed specific response to CTC, resulting in a decrease in fluorescence intensity at 345 nm, a blue shift, and an increase in fluorescence intensity at 450 nm. The obtained DECDs exhibited highly selective response to CTC and not to its analogues, such as tetracycline, doxycycline, and oxytetracycline. Thus, an excellent ratiometric probe for the detection of CTC was fabricated successfully and used for the detection of CTC in real samples with the detection limit (LOD) of 16.45 nM. More importantly, the DECDs were used for quantitative detection of CTC in living cells, which demonstrated excellent biocompatibility and broad prospects in biomedicine application. Finally, the excellent selectivity of DECDs toward CTC was attributed to the FRET mechanism and the formation of complexes.

A NIR-emissive probe with a remarkable Stokes shift for CO-releasing molecule-3 detection in cells and in vivo.

Carbon monoxide (CO) is regarded as one of the most important gaseous transmitters, playing a vital role in biological systems; meanwhile, abnormal levels of CO can be correlated with conditions such as lung disease, Alzheimer's disease, and cardiovascular disease. CO-releasing molecules (CORMs) are chemical agents used to release CO as an endogenous, biologically active molecule in order to treat diseases. CO-releasing molecule-3 (CORM-3), as a convenient and safe CO donor and therapeutic drug molecule, has been widely used to release exogenous CO in living cells to study the physiological and pathological roles of CO in living systems. Herein, we designed a NIR-emitting probe (NIR-CORM-3) with a large Stokes shift based on a 4-(dimethylamino)cinnamaldehyde lepidine derived fluorophore. A 4-nitrobenzyl group was selected as the CORM-3 recognizing moiety, and the probe is able to selectively and sensitively respond to CORM-3 (within only 15 min). Upon encountering CORM-3, NIR-CORM-3 releases a fluorophore with a response at 670 nm, and it shows a remarkable Stokes shift (up to 250 nm). In addition, NIR-CORM-3 has low cytotoxicity and exhibits outstanding NIR imaging abilities in living cells and mice.

Label-free detection of ssDNA base insertion and deletion mutations by surface-enhanced Raman spectroscopy.

Surface-enhanced Raman spectroscopy (SERS), as a label-free, highly sensitive analytical method, has become an important tool for providing substance fingerprints. In this study, silver nanoparticles containing thiosulfate ions and calcium ions (Ag@SCNPs) have been used as an enhanced substrate to eliminate the interference of impurities on DNA signals. Intrinsic structural information on single-strand DNA (ssDNA) was directly obtained through SERS. The improved enhancement system was used to explore the base-stacking rules of ssDNA in a solution environment. For the first time, single-base insertion mutations and deletion mutations, as well as their exact mutation sites, were identified, and Raman spectra with high stability, repeatability, and high signal-to-noise ratio were obtained. The method is simple, fast, and accurate, and the detection process is nondestructive. It has potential to be applied in the fields of medical diagnosis and genetics research.