Fluorescent Biomarkers Research Articles

Multicomponent double Povarov reaction for julolidine: Synthesis and mechanistic insights

Julolidines constitute a class of N-heterocyclic molecules that behave as molecular rotors. Due to their fluorescent properties, they are applied in a wide range of technological fields, such as the production of solar cells, fluorescent biomarkers or bioimaging, and photoconductive materials. In the present work, we developed a methodology for the synthesis of julolidines through the one-pot tandem reaction-based application of multicomponent double Povarov reaction (MCPR) using BF3.OEt2 as the catalyst (25 mol%), star anise oil rich in trans-anethole as the substrate, and water as the solvent in reactions at room temperature. The julolidines were obtained with total yields ranging from 55 to 95 %. A mechanistic study allowed for the conclusion that these MCPRs take place through an ionic mechanism and also that released protons by the reaction between BF3.Et2O and water are involved in the catalytic process. After extracting the products from the reaction medium, the remaining aqueous phase containing the catalyst can be reused for up to six catalytic cycles with a minimal loss of catalytic efficiency. DFT calculations were conducted to investigate the catalytic cycle using BF3.Et2O and ZnCl2 as catalysts. The results indicate that the formation of iminium ions is a prerequisite for the progress of the reaction (MCPR). When BF3.Et2O and water are involved, the reaction proceeds via Brønsted catalysis, and the formation of iminium ions occurs in an exothermic and spontaneous process. However, when the ZnCl2 is used, the process is Lewis catalyzed to form the first iminium ion and is endergonic, shifting the equilibrium towards the reactants and inhibiting the cyclization.

Development of a novel testis-on-a-chip that demonstrates reciprocal crosstalk between Sertoli and Leydig cells in testicular tissue

The reciprocal crosstalk between testicular Sertoli and Leydig cells plays a vital role in supporting germ cell development and maintaining testicular characteristics and spermatogenesis. Conventional 2D and the recent 3D assay systems fail to accurately replicate the dynamic interactions between these essential endocrine cells. Furthermore, most in vitro testicular tissue models lack the ability to capture the complex multicellular nature of the testis. To address these limitations, we developed a 3D multicellular testis-on-a-chip platform that effectively demonstrates the reciprocal crosstalk between Sertoli cells and the adjacent Leydig cells while incorporating various human testicular tissue constituent cells and various natural polymers infused with blood coagulation factors. Additionally, we identified SERPINB2 as a biomarker of male reproductive toxicity that is activated in both Sertoli and Leydig cells upon exposure to various toxicants. Leveraging this finding, we designed a fluorescent reporter-conjugated toxic biomarker detection system that enables both an intuitive and quantitative assessment of material toxicity by measuring the converted fluorescence intensity. By integrating this fluorescent reporter system into the Sertoli and Leydig cells within our 3D multicellular chip platform, we successfully developed a testis-on-chip model that can be utilized to evaluate the male reproductive toxicity of potential drug candidates. This innovative approach holds promise for advancing toxicity screening and reproductive research.

Fresnel lens three-dimensionally printed on the facet of a single mode fiber for trapping, manipulation, and spectrum.

Fiber optical tweezers (FOTs) provide a functionality for micro-/nanoparticle manipulation with a slim and flexible optical fiber setup. An added in situ spectroscopic functionality can achieve characterization of the trapped particle, potentially useful for endoscopic, in-vivo studies in an inherently heterogeneous environment if the applicator end is all-fiber-built. Here, we demonstrate all-fiber optical tweezers (a-FOTs) for the trapping and in situ spectral measurement of a single, cell-sized microparticle. The key to ensure the simultaneous bifunctionality is a high numerical aperture (NA) Fresnel lens fabricated by two-photon direct laser writing (DLW) corrected by grid-correction methods. We demonstrate trapping and time-resolved, in situ spectroscopy of a single upconversion particle (UCP), a common fluorescent biomarker in biophotonics. The system achieves a 0.5-s time resolution in the in situ spectral measurement of a trapped UCP. The all-fiber designed system preserves the advantages of flexibility and robustness of the fiber, potentially useful for in-vivo biomedical studies such as cell-to-cell interactions, pH and temperature detection, and nucleic acids detection.

Decoupling excitons from high-frequency vibrations in organic molecules

The coupling of excitons in π-conjugated molecules to high-frequency vibrational modes, particularly carbon–carbon stretch modes (1,000–1,600 cm−1) has been thought to be unavoidable1,2. These high-frequency modes accelerate non-radiative losses and limit the performance of light-emitting diodes, fluorescent biomarkers and photovoltaic devices. Here, by combining broadband impulsive vibrational spectroscopy, first-principles modelling and synthetic chemistry, we explore exciton–vibration coupling in a range of π-conjugated molecules. We uncover two design rules that decouple excitons from high-frequency vibrations. First, when the exciton wavefunction has a substantial charge-transfer character with spatially disjoint electron and hole densities, we find that high-frequency modes can be localized to either the donor or acceptor moiety, so that they do not significantly perturb the exciton energy or its spatial distribution. Second, it is possible to select materials such that the participating molecular orbitals have a symmetry-imposed non-bonding character and are, thus, decoupled from the high-frequency vibrational modes that modulate the π-bond order. We exemplify both these design rules by creating a series of spin radical systems that have very efficient near-infrared emission (680–800 nm) from charge-transfer excitons. We show that these systems have substantial coupling to vibrational modes only below 250 cm−1, frequencies that are too low to allow fast non-radiative decay. This enables non-radiative decay rates to be suppressed by nearly two orders of magnitude in comparison to π-conjugated molecules with similar bandgaps. Our results show that losses due to coupling to high-frequency modes need not be a fundamental property of these systems.

Monomeric Far-red and Near-infrared Fluorescent Biliproteins of Ultrahigh Brightness.

Far-red and near-infrared fluorescent proteins have regions of maximum transmission in most tissues and can be widely used as fluorescent biomarkers. We report that fluorescent phycobiliproteins originating from the phycobilisome core subunit ApcF2 can covalently bind biliverdin, named BDFPs. To further improve BDFPs, we conducted a series of studies. Firstly, we mutated K53Q and T144A of BDFPs to increase their effective brightness up to 190 % in vivo. Secondly, by homochromatic tandem fusion of high-brightness BDFPs to achieve monomerization, which increases the effective brightness by up to 180 % in vivo, and can effectively improve the labeling effect. By combining the above two approaches, the brightness of the tandem BDFPs was much improved compared with that of the previously reported fluorescent proteins in a similar spectral range. The tandem BDFPs were expressed stably while maintaining fluorescence in mammalian cells and Caenorhabditis elegans. They were also photostable and resistant to high temperature, low pH, and chemical denaturation. The tandem BDFPs advantages were proved in applications as biomarkers for imaging in super-resolution microscopy.

A Review for Artificial Intelligence Based Protein Subcellular Localization.

Proteins need to be located in appropriate spatiotemporal contexts to carry out their diverse biological functions. Mislocalized proteins may lead to a broad range of diseases, such as cancer and Alzheimer's disease. Knowing where a target protein resides within a cell will give insights into tailored drug design for a disease. As the gold validation standard, the conventional wet lab uses fluorescent microscopy imaging, immunoelectron microscopy, and fluorescent biomarker tags for protein subcellular location identification. However, the booming era of proteomics and high-throughput sequencing generates tons of newly discovered proteins, making protein subcellular localization by wet-lab experiments a mission impossible. To tackle this concern, in the past decades, artificial intelligence (AI) and machine learning (ML), especially deep learning methods, have made significant progress in this research area. In this article, we review the latest advances in AI-based method development in three typical types of approaches, including sequence-based, knowledge-based, and image-based methods. We also elaborately discuss existing challenges and future directions in AI-based method development in this research field.

NIR-emissive carbon nanodots as a tool to mark ribosomal RNA and nucleolus components using super-resolution microscopy.

Ribosomal RNA (rRNA) plays a key role in protein synthesis and ribosomal biogenesis. The exclusively used commercial dye for RNA staining is SYTO RNASelect, which works in fixed cells only. To overcome this constraint, we synthesized NIR-emissive, highly photostable, and biocompatible carbon nanodots (CNDs) as a fluorescent biomarker for rRNA. The synthesized CNDs could stain rRNA in both live and fixed cells. We were able to visualize rRNA at different sites in eukaryotic cells using super-resolution microscopy (SRM). The CNDs localized rRNA in the dense fibrillar components (DFCs) of the nucleolus, nuclear membrane, and rough endoplasmic reticulum (RER). The super-resolved hollow ring-structured DFC with an FWHM of 140 nm, nuclear membrane with an FWHM of 120 nm, and ER with an FWHM of 115 nm were observed. We further found a marked contrast between the pre-RNA synthesized in cancer cells and normal cells. We believe that these CNDs have great potential in rRNA imaging and comprehending the complex relationships between rRNA dynamics and basic biological processes, disease development, or drug interactions.

Modern methods of the diagnostic of pathology of pregnancy and the postpartum period

Postpartum purulent-inflammatory diseases are currently a serious problem. Purpose - to develop and implement of a new modern method of the diagnosis, monitoring and assessment of health of women during pregnancy, before childbirth and in the postpartum period - the method of fluorescence spectroscopy - to ensure the provision of highly qualified medical care, including the effective treatment. Materials and methods. The research material consisted of blood serum samples of 265 patients. There were 40 pregnant women (the Group 1), 40 women with an uncomplicated postpartum period (the Group 2), 170 - with postpartum purulent-inflammatory diseases (the Group 3), 15 patients with sepsis (the Group 4). Diagnostic methods: clinical, laboratory, instrumental, method of fluorescence spectroscopy, statistical (logistic regression and ROC analysis methods). Results. In the Group 1 there is an increase in the intensity of fluorescence to 1.3 r.u. For the Group 2 the intensity of fluorescence was within 0.86-1.0 r.u. For the Group 3, the decrease in fluorescence intensity from 1 to 0.35 r.u. was recorded. For the Group 4 in addition to decreasing the fluorescence intensity, a noticeable shift of the fluorescence spectra of blood serum into the long-wave range was recorded. Conclusions. A reliable prognostic model of the development of postpartum purulent-inflammatory diseases was created. The modern approach for the diagnosis and effective control of treatment within the framework of the method of fluorescent spectroscopy and biomarkers using infusions of donor albumin solutions is proposed. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of participating institution. The informed consent of the patient was obtained for conducting the studies. No conflict of interest was declared by the authors.

Regularized reconstruction based on joint smoothly clipped absolute deviation regularization and graph manifold learning for fluorescence molecular tomography

Objective. Fluorescence molecular tomography (FMT) is an optical imaging modality that provides high sensitivity and low cost, which can offer the three-dimensional distribution of biomarkers by detecting the fluorescently labeled probe noninvasively. In the field of preclinical cancer diagnosis and treatment, FMT has gained significant traction. Nonetheless, the current FMT reconstruction results suffer from unsatisfactory morphology and location accuracy of the fluorescence distribution, primarily due to the light scattering effect and the ill-posed nature of the inverse problem. Approach. To address these challenges, a regularized reconstruction method based on joint smoothly clipped absolute deviation regularization and graph manifold learning (SCAD-GML) for FMT is presented in this paper. The SCAD-GML approach combines the sparsity of the fluorescent sources with the latent manifold structure of fluorescent source distribution to achieve more accurate and sparse reconstruction results. To obtain the reconstruction results efficiently, the non-convex gradient descent iterative method is employed to solve the established objective function. To assess the performance of the proposed SCAD-GML method, a comprehensive evaluation is conducted through numerical simulation experiments as well as in vivo experiments. Main results. The results demonstrate that the SCAD-GML method outperforms other methods in terms of both location and shape recovery of fluorescence biomarkers distribution. Siginificance. These findings indicate that the SCAD-GML method has the potential to advance the application of FMT in in vivo biological research.

In vitro and in vivo nanomolar Hg2+ detection in live cells and zebrafish, theoretical studies

A worldwide contaminant that has an impact on both environment and human health is mercury. Neurological disorders are eventually caused by mercury bioaccumulation in the nervous system and ultimately affecting other parts of the body. It has been an indispensable task to sensitively and selectively sense mercury in order to control the damage. In this regard, an effectual chemosensor for the trace detection of Hg2+ ions has been synthesized appertaining to imidazole-coumarin cores with extremely lower cytotoxicity (15±0.15 µM).The sensing efficiency of IMCT was assessed in aqueous acetonitrile medium. The probe IMCT demonstrated its high sensitivity towards Hg2+ ions with a limit of detection (LOD) of 23.64 nM, which is extremely lower than the World Health Organization (WHO) international norms acceptable mercury level in drinking water (6.0 µg/L). ESI-Mass spectrum and Job’s result substantiates the complex formation of IMCT with Hg2+in 1:1 ratio. In vitro and in vivo imaging was carried out in zebrafish and human cancer cells. These results illustrate the effectiveness of IMCT as a fluorescent biomarker for Hg2+ has been effectively demonstrated.

Effects of drought stress induced by D-Mannitol on the germination and early seedling growth traits, physiological parameters and phytochemicals content of Tunisian squash (Cucurbita maximaDuch.) landraces.

Drought stress is one of the most devastating environmental stressors, especially in the arid and semi-arid regions of the world. Considering the major constraints that drought stress poses to crop production and the consequent yield losses in food crops, breeding for climate-resilient crops is an efficient means to mitigate stress conditions. This study aimed at evaluating the response of four squash (Cucurbita maxima Duchesne) landraces to drought stress at germination and at plant stage. Drought stress was induced by different concentrations of D-mannitol (-0.24, -0.47 and -0.73 MPa). The tested parameters at germination stage included germination percentage, seedling vigor index, seed water absorbance and seedling growth potential. At the plant stage, leaf chlorophyll and carotenoids content, chlorophyll fluorescence, evapotranspiration, photosynthesis activity and several biomarkers, namely malondialdehyde, proline, total phenols content, total flavonoids content and DPPH radical scavenging activity were evaluated in both roots and leaves. Our results indicate a magnitude of drought stress effects reflected via repression of germination and seedling growth as well as adjustments in physiological functions at later growth stages, in a genotype depended manner. Among landraces, "751" and "746" showed better performance, as evidenced by higher seed germination and seedling growth potential even at high stress levels (-0.47 and - 0.73 MPa), whereas "747" was the most sensitive landrace to drought stress at both tested stages. In conclusion, our findings highlight the importance of squash landraces selection for the identification of elite genotypes with increased tolerance to drought stress.

Structural Characterization of Fluorescent Proteins Using Tunable Femtosecond Stimulated Raman Spectroscopy.

The versatile functions of fluorescent proteins (FPs) as fluorescence biomarkers depend on their intrinsic chromophores interacting with the protein environment. Besides X-ray crystallography, vibrational spectroscopy represents a highly valuable tool for characterizing the chromophore structure and revealing the roles of chromophore-environment interactions. In this work, we aim to benchmark the ground-state vibrational signatures of a series of FPs with emission colors spanning from green, yellow, orange, to red, as well as the solvated model chromophores for some of these FPs, using wavelength-tunable femtosecond stimulated Raman spectroscopy (FSRS) in conjunction with quantum calculations. We systematically analyzed and discussed four factors underlying the vibrational properties of FP chromophores: sidechain structure, conjugation structure, chromophore conformation, and the protein environment. A prominent bond-stretching mode characteristic of the quinoidal resonance structure is found to be conserved in most FPs and model chromophores investigated, which can be used as a vibrational marker to interpret chromophore-environment interactions and structural effects on the electronic properties of the chromophore. The fundamental insights gained for these light-sensing units (e.g., protein active sites) substantiate the unique and powerful capability of wavelength-tunable FSRS in delineating FP chromophore properties with high sensitivity and resolution in solution and protein matrices. The comprehensive characterization for various FPs across a colorful palette could also serve as a solid foundation for future spectroscopic studies and the rational engineering of FPs with diverse and improved functions.

Technologic advances in robot-assisted nephron sparing surgery: a narrative review.

Nephron sparing surgery (NSS) is the preferred management for clinical stage T1 (cT1) renal masses. In recent years, indications have expanded to larger and more complex renal tumors. In an effort to provide optimal patient outcomes, urologists strive to achieve the pentafecta when performing partial nephrectomy. This has led to the continuous technologic advancement and technique refinement including the use of augmented reality, ultrasound techniques, changes in surgical approach and reconstruction, uses of novel fluorescence marker guided imaging, and implementation of early recovery after surgery (ERAS) protocols. The aim of this narrative review is to provide an overview of the recent advances in pre-, intra-, and post-operative management and approaches to managing patients with renal masses undergoing NSS. We performed a non-systematic literature search of PubMed and MEDLINE for the most relevant articles pertaining to the outlined topics from 2010 to 2022 without limitation on study design. We included only full-text English articles published in peer-reviewed journals. Partial nephrectomy is currently prioritized for cT1a renal masses; however, indications have been expanding due to a greater understanding of anatomy and technologic advances. Recent studies have demonstrated that improvements in imaging techniques utilizing cross-sectional imaging with three-dimensional (3D) reconstruction, use of color doppler intraoperative ultrasound, and newer studies emerging using contrast enhanced ultrasound play important roles in certain subsets of patients. While indocyanine green administration is commonly used, novel fluorescence-guided imaging including folate receptor-targeting fluorescence molecules are being investigated to better delineate tumor-parenchyma margins. Augmented reality has a developing role in patient and surgical trainee education. While pre-and intra-operative imaging have shown to be promising, near infrared guided segmental and sub-segmental vessel clamping has yet to show significant benefit in patient outcomes. Studies regarding reconstructive techniques and replacement of reconstruction with sealing agents have a promising future. Finally, ERAS protocols have allowed earlier discharge of patients without increasing complications while improving cost burden. Advances in NSS have ranged from pre-operative imaging techniques to ERAS protocols Further prospective investigations are required to determine the impact of novel imaging, in-vivo fluorescence biomarker use, and reconstructive techniques on achieving the pentafecta of NSS.

Amino-Termination of Silicon Carbide Nanoparticles.

Silicon carbide nanoparticles (SiC NPs) are promising inorganic molecular-sized fluorescent biomarkers. It is imperative to develop methods to functionalize SiC NPs for certain biological applications. One possible route is to form amino groups on the surface, which can be readily used to attach target biomolecules. Here, we report direct amino-termination of aqueous SiC NPs. We demonstrate the applicability of the amino-terminated SiC NPs by attaching bovine serum albumin as a model for functionalization. We monitor the optical properties of the SiC NPs in this process and find that the fluorescence intensity is very sensitive to surface termination. Our finding may have implications for a few nanometers sized SiC NPs containing paramagnetic color centers with optically read electron spins.

Facile green synthesis and characterization of fluorescent nanoprobe based on Ca, K, N-doped carbon quantum dots derived from Aegle marmelos for bioimaging of human neuroblastoma cancer cells and living organisms

This study demonstrated an environmentally responsible, inexpensive and simple one-step hydrothermal method to synthesize biocompatible fluorescent carbon quantum dots (CQDs) from Aegle marmelos fruit extract. The near-spherical CQDs were discovered to have a naturally distributed size of 3–6 nm, were unintentionally doped with heteroatoms (Ca, K, and N) without the need for doping element precursors due to mineral contents in extract, had a quantum yield of about 4.06%, strong photostability, and excellent water solubility. Several morphological, compositional, physicochemical, and optical properties were studied. Other variables influencing CQD photoluminescence, such as hydrothermal process parameters and pH sensitivity, were also examined. Zeta potential analysis showed a negative surface charge with a zeta potential value of −5.29 mV and good dispersibility in aqueous solution. Furthermore, as an alternative to organic or synthetic probes, there is a huge need for the development of simple, affordable, and non-destructive fluorescent biomarkers. As-synthesized Ca, K, N-doped CQDs have demonstrated good fluorescent staining abilities and may be employed as a helpful probe for bio-imaging of cancer cells and other organisms. Cell survival and cytotoxicity were found to be satisfactory, with 90% of SH-SY5Y and HCT-116 cells surviving, compared to 63–77% for the other organisms, even at higher dosages (200 µg/mL) for up to 4 days.

Carboxyl-BODIPY based fluorescent biomarkers: Spectral characteristics, photostability and possibilities for practical application

A comparative analysis of the structural and solvation factors on the spectral properties, pH stability, photostability, and lipophilicity of BODIPY luminophores containing carboxylic acid residues in α- and meso-position was carried out. The interaction of these BODIPYs with cells of microscopic fungi (Candida albicans and Fusarium solani) was studied. The compounds were found to be stable across a wide range of pH values and exhibited intense fluorescence (to φ ∼ 94%) at 508–587 nm. The introduction of a carboxylic acid residue into the meso-position of the BODIPY core causes a noticeable increase (almost ∼2 times) of the Stokes shift compared to the meso-unsubstituted analogues. On the other hand, α-carboxyl-BODIPYs showed a red shift in both the absorption and fluorescence bands. Effective fluorescence quenching (up to 40–80%) was observed in electron donor solvents for carboxyl-BODIPYs, especially for the carboxylic acid BODIPY with a thiophene substituent. The presence of a carboxyl group in the α-position of the BODIPY increased its affinity to hydrophilic media by approximately ∼1.2–2 times compared to meso-carboxyl-BODIPYs. Given the lack of cytotoxicity, carboxyl-BODIPYs may be recommended as effective biomarkers for examining the differences between a wide range of pathogens causing mycotic.

A Spectrofluorometric Method for Real-Time Graft Assessment and Patient Monitoring.

Biomarkers are powerful clinical diagnostics and predictors of patient outcome. However, robust measurements often require time and expensive laboratory equipment, which is insufficient to track rapid changes and limits direct use in the operating room. Here, this study presents a portable spectrophotometric device for continuous real-time measurements of fluorescent and non-fluorescent biomarkers at the point of care. This study measures the mitochondrial damage biomarker flavin mononucleotide (FMN) in 26 extended criteria human liver grafts undergoing hypothermic oxygenated perfusion to guide clinical graft assessment. Real-time data identified seven organs unsuitable for transplant that are discarded. The remaining grafts are transplanted and FMN values correlated with post-transplant indicators of liver function and patient recovery. Further, this study shows how this device can be used to monitor dialysis patients by measuring creatinine in real-time. Ourapproach provides a simple method to monitor biomarkers directly within biological fluids to improve organ assessment, patient care, and biomarkerdiscovery.

TSA-PACT: a method for tissue clearing and immunofluorescence staining on zebrafish brain with improved sensitivity, specificity and stability

For comprehensive studies of the brain structure and function, fluorescence imaging of the whole brain is essential. It requires large-scale volumetric imaging in cellular or molecular resolution, which could be quite challenging. Recent advances in tissue clearing technology (e.g. CLARITY, PACT) provide new solutions by homogenizing the refractive index of the samples to create transparency. However, it has been difficult to acquire high quality results through immunofluorescence (IF) staining on the cleared samples. To address this issue, we developed TSA-PACT, a method combining tyramide signal amplification (TSA) and PACT, to transform samples into hydrogel polymerization frameworks with covalent fluorescent biomarkers assembled. We show that TSA-PACT is able to reduce the opacity of the zebrafish brain by more than 90% with well-preserved structure. Compared to traditional method, TSA-PACT achieves approximately tenfold signal amplification and twofold improvement in signal-to-noise ratio (SNR). Moreover, both the structure and the fluorescent signal persist for at least 16 months with excellent signal retention ratio. Overall, this method improves immunofluorescence signal sensitivity, specificity and stability in the whole brain of juvenile and adult zebrafish, which is applicable for fine structural analysis, neural circuit mapping and three-dimensional cell counting.

Dissecting Sperm Mitochondrial G-Quadruplex Structures Using a Fluorescent Probe Biomarker to Monitor and Regulate Fertilization Capability.

To monitor the levels of mitochondrial DNA G-quadruplexes (mtDNA G4s) in spermatozoa and to explore the possibility using mtDNA G4s as a reliable marker in patients with multiple clinical insemination failures, a novel chemical TPE-mTO probe engineered in our previous work was used on both samples from the mice sperm and from patients with fertilization failure. Expression of valosin-containing protein and the zona-free hamster egg assay were used to evaluate mitophagy and human sperm penetration. RNA-sequencing was used to explore expression changes of key genes affected by mtDNA G4s. Results showed that the probe can track mtDNA G4s in spermatozoa easily and quickly with fewer backgrounds. Significantly increased mtDNA G4s were also found in patients with fertilization failure, using the flow-cytometry-based TPE-mTO probe detection method. A sperm-hamster egg penetration experiment showed that abnormal fertilization caused by increased mtDNA G4s can be effectively restored by a mitophagy inducer. This study provides a novel method for monitoring etiological biomarkers in patients with clinical infertility and treatment for patients with abnormal fertilization caused by mtDNA G4 dysfunction.

Swept-source multimode fiber imaging

High-resolution compressive imaging via a flexible multimode fiber is demonstrated using a swept-laser source and wavelength dependent speckle illumination. An in-house built swept-source allowing for independent control of bandwidth and scanning range is used to explore and demonstrate a mechanically scan-free approach for high-resolution imaging through an ultrathin and flexible fiber probe. The computational image reconstruction is shown by utilizing a narrow sweeping bandwidth of < 10 nm while acquisition time is decreased by 95% compared to conventional raster scanning endoscopy. Demonstrated narrow-band illumination in the visible spectrum is vital for the detection of fluorescence biomarkers in neuroimaging applications. The proposed approach yields device simplicity and flexibility for minimally invasive endoscopy.