Biology subjects

Demirci, U.

Publications and source records attributed to Demirci, U..

11 recordsLinked to original sources

bioRxiv2026

Glio-SERS: Label-Free Molecular Profiling of Plasma Extracellular Vesicles in Brain Tumors Using SERS and Artificial Intelligence

Extracellular vesicles are increasingly recognized as important carriers of disease-associated molecular information, yet robust methods for their isolation and molecular characterization from limited clinical samples remain challenging. Here, we present an integrated approach combining standardized EV isolation, label-free Surface-Enhanced Raman Spectroscopy (SERS), and artificial intelligence (AI) for comprehensive molecular profiling of small extracellular vesicles (sEVs) from human plasma. Here, we show systematically isolated and characterized plasma sEVs using ExoTIC in accordance with MISEV2023 guidelines, with SERS analysis revealing quantifiable spectral differences across samples from patients with glioblastoma (n=20) and meningioma (n=23) compared to healthy controls (n=30). Among the evaluated AI models, the convolutional neural network most effectively captured group-level spectral differences in sEVs, achieving accuracies up to 88% in this pilot cohort. Further, an EGFR-based spectral regression model was explored to examine molecular variability across sEV samples. Parallel proteomic analysis presented statistically significant differences in several proteins elevated in glioblastoma or meningioma. This label-free, rapid approach provides a proof-of-concept framework for sEV molecular profiling establishing the basis for broad validation studies across diverse diseases.

bioengineering↗

bioRxiv2026

Analysis of Plasma Extracellular Vesicles in Normal-Weight and Overweight Type 2 Diabetes Using Multimodal SERS and RNA-Seq

AimsTo characterize subtype-associated heterogeneity in type 2 diabetes mellitus (T2DM), particularly normal-weight diabetes, using extracellular vesicle (EV)-associated molecular features in a clinically stratified cohort. MethodsEVs were isolated from plasma using ExoTIC and validated by transmission electron microscopy, nanoparticle tracking analysis, flow cytometry, and Western blotting. EVs from Asian normal-weight (A-NWD), Asian overweight (A-OWD), Non-Hispanic White normal-weight (W-NWD), and Non-Hispanic White overweight (W-OWD) T2DM patients were analyzed by multimodal surface-enhanced Raman spectroscopy (SERS; n=65) and EV-RNA sequencing (n=39). ResultsSERS identified subgroup-associated spectral fingerprints that distinguished the four BMI- and race/ethnicity-defined groups in this cohort. EV-RNA sequencing revealed differential microRNA expression across subgroups, with higher miR-208a and miR-132 in A-OWD and higher miR-484 in A-NWD. Unsupervised analyses also showed partially overlapping EV-associated molecular features between A-NWD and W-OWD, suggesting that BMI-based subgrouping alone may not fully capture shared metabolic states. ConclusionsMultimodal EV profiling identified subgroup-associated spectral and miRNA features in clinically stratified T2DM and provides a framework for studying diabetes heterogeneity, including molecular patterns associated with normal-weight diabetes.

bioengineering↗

bioRxiv2025

Broad-Spectrum HIV-1 Detection and Neutralization via Multivalent Designer DNA Nanostructures

Early and accurate detection of HIV-1 remains a critical unmet need, particularly during the acute phase of infection when viral loads are low and transmission risk is highest. Here, we report a modular diagnostic and antiviral platform based on designer DNA nanostructures engineered for high-affinity recognition of the HIV-1 envelope glycoprotein (GP120). A custom DNA aptamer, termed HINT, was developed to bind GP120 across major HIV-1 subtypes (Groups M and P; subtypes A and B) with nanomolar affinity. To amplify binding strength, HINT aptamers were spatially patterned onto a net-shaped DNA nanostructure (DNA-NetHINT) that geometrically matches the trimeric GP120 spikes on the viral surface. Using multivalent interactions, the nanostructure enabled up to 104-fold improvement in binding affinity (sub-picomolar KD), confirmed by surface plasmon resonance. Integration of DNA-NetHINT into a paper-based lateral flow assay produced a low-cost, saliva-compatible self-testing device capable of detecting intact HIV-1 virions at concentrations as low as 328 viral copies per test, outperforming commercial fourth-generation rapid diagnostic tests. In addition to its diagnostic capabilities, the DNA-NetHINT construct exhibited potent antiviral activity, reducing pseudovirus infection with an EC50 of [~]1.8 nM, nearly 1,000-fold more effective than free aptamers. This work demonstrates a dual-function DNA nanotechnology platform that enables both ultrasensitive HIV-1 detection and entry inhibition. The approach is broadly applicable to other enveloped viruses and represents a promising step toward next-generation molecular theranostics for infectious disease management.

bioengineering↗

bioRxiv2025

A Microneedle Device for Rapid Dermal Interstitial Fluid Sampling

Dermal interstitial fluid (ISF) offers a promising alternative to invasive blood tests and opportunities for novel skin diagnostics. Progress in both the understanding and adoption of ISF tests is hindered by sampling challenges, including lengthy collection times, non-negligible failure rates, variable collection volumes, and inconsistent bioanalyte levels. The causes of many of these issues are not well understood. We demonstrate a microneedle device that is several times faster than state-of-the-art, collecting an average of 15.5 mg of ISF in 5 minutes in humans with near-zero failure rate. This improvement was achieved by designing the spatial pressure gradient driving ISF flow. The influence of penetration depth, collection time, pressure, and age on ISF collection was elucidated, with Darcys law explaining multiple observations. A data-driven acceptance criterion of <1% blood contamination for ISF is proposed. The device and findings presented will empower researchers to better conduct robust studies in the development of ISF diagnostics.

bioengineering↗

bioRxiv2025

SHINE: SERS-based Hepatotoxicity detection using Inference from Nanoscale Extracellular vesicle content

Extracellular vesicles (EV) are becoming crucial tools in liquid biopsy, diagnostics, and therapeutic applications, yet their nanoscale characterization remains challenging. In this context, the detection of drug-induced liver injury, i.e., hepatotoxicity, through extracellular vesicle molecular content remains an unexplored frontier. To this end, we present a label-free surface-enhanced Raman (SERS) spectroscopy approach, which provides rapid EV content analysis under ten minutes and requires only 1.3 microliters of sample. Using hepatic cultures as a model, our platform captures distinct and reproducible EV molecular changes in response to acetaminophen-induced hepatoxicity. Our platform achieves exceptional accuracy with root mean squared error values as low as 3.80%, establishing strong correlations between EV spectra and conventional toxicity biomarkers. Unlike previous EV-SERS studies limited to vesicle identification and disease markers, this approach reveals EV drug-response signatures strongly correlated with conventional toxicity markers. These findings establish EVs as dynamic reporters of cellular drug responses and demonstrate use of SERS-based EV detection of hepatotoxicity.

biophysics↗

bioRxiv2022

A Photonic Resonator Interferometric Scattering Microscope for Label-free Detection of Nanometer-Scale Objects with Digital Precision in Point-of-Use Environments

Label-free detection and digital counting of nanometer-scaled objects such as nanoparticles, viruses, extracellular vesicles, and protein molecules enable a wide range of applications in cancer diagnostics, pathogen detection, and life science research. The contrast of interferometric scattering microscopy is amplified through a photonic crystal surface, upon which scattered light from an object combines with illumination from a monochromatic plane wave source. The use of a photonic crystal substrate for interference scattering microscopy results in reduced requirements for high-intensity lasers or oil-immersion objectives, thus opening a pathway toward instruments that are more suitable for environments outside the optics laboratory. Here, we report the design, implementation, and characterization of a compact Photonic Resonator Interferometric Scattering Microscope (PRISM) designed for point-of-use environments and applications. The instrument incorporates two innovative elements that facilitate operation on a desktop in ordinary laboratory environments by users that do not have optics expertise. First, because scattering microscopes are extremely sensitive to vibration, we incorporated an inexpensive but effective solution of suspending the instruments main components from a rigid metal framework using elastic bands, resulting in an average of 28.7 dBV reduction in vibration amplitude compared to an office desk. Second, an automated focusing module based on the principle of total internal reflection maintains the stability of image contrast over time and spatial position, facilitating automated data collection. In this work, we characterize the systems performance by measuring the contrast from gold nanoparticles with diameters in the 10-40 nm range and by observing various biological analytes, including HIV virus, SARS-CoV-2 virus, exosomes, and ferritin protein.

bioengineering↗

bioRxiv2022

Target Recycling Amplification Process for Digital Detection of Exosomal MicroRNAs Through Photonic Resonator Absorption Microscopy

Exosomal microRNAs (miRNAs) have considerable potential as pivotal biomarkers to monitor cancer development, dis-ease progression, treatment effects and prognosis. Here, we report an efficient target recycling amplification process (TRAP) for the digital detection of exosomal miRNAs using photonic resonator absorption microscopy (PRAM). Through toehold-mediated DNA strand displacement reactions, we achieve multiplex digital detection with sub-attomolar sensitivity in 20 minutes, robust selectivity for single nucleotide variants, and a broad dynamic range from 1 aM to 1 pM. We then applied our TRAP system to quantify miRNA in exosomal total RNAs isolated from human cancer cell lines. Compared with traditional qRT-PCR methods, TRAP showed similar accuracy in profiling exosomal miRNAs derived from cancer cells, but also exhibited at least 31-fold and 61-fold enhancement in the limits of miRNA-375 and miRNA-21 detection, respectively. The TRAP approach is ideal for exosomal or circulating miRNA biomarker quantification, where the miRNAs are present in low concentrations or sample volume, with potentials for frequent, low-cost, and minimally invasive point-of-care testing.

bioengineering↗

bioRxiv2022

Extracellular RNA signatures of mutant KRAS(G12C) lung adenocarcinoma cells

Extracellular RNAs (exRNAs) are actively secreted from cells in membrane-bound extracellular vesicles (EVs). Diverse classes of RNAs are secreted as exRNAs, including messenger RNAs (mRNAs), long noncoding RNAs (lncRNAs), and transposable element RNAs (TE RNAs). However, the full composition and clinical utility of exRNAs secreted in response to oncogenic signaling are unknown. Here we use both affinity- and nanofiltration-based EV isolation approaches to show that mutant KRAS(G12C) signaling results in the secretion of specific lncRNAs, TE RNAs, and mRNAs, some of which are prognostic for lung adenocarcinoma (LUAD) patient survival. We found that inhibition of KRAS(G12C) signaling broadly reprograms the noncoding transcriptome, as evidenced by a substantial increase in TE RNA secretion. KRAS(G12C) inhibition also increased the abundance of secreted lncRNAs and retained intron-containing transcripts, while decreasing the mRNA content of EVs. Oncogenic KRAS(G12C) signaling was required for the secretion of mRNAs from a set of 20 genes that are significantly associated with unfavorable clinical outcomes in LUAD. Our study suggests that both coding and noncoding RNAs that are secreted in EVs may serve as KRAS(G12C)-specific signatures for diagnosing lung cancer.

genomics↗

bioRxiv2021

Endogenous Retroviral Elements Generate Pathologic Neutrophils and Elastase Rich Exosomes in Pulmonary Arterial Hypertension

Neutrophil elastase (NE) is implicated in pulmonary arterial hypertension (PAH) but the role of neutrophils in the pathogenesis of PAH is unclear. Here we show that neutrophils from PAH vs. control subjects produce and release increased NE associated with enhanced extracellular trap formation. PAH neutrophils are highly adherent and show decreased migration consistent with increased vinculin, identified on proteomic analysis and previously linked to an antiviral response. This was substantiated by a transcriptomic interferon signature in PAH neutrophils and an increase in human endogenous retrovirus (HERV-K) envelope protein. NE and interferon genes are induced by HERV-K envelope and vinculin is increased by HERV-K dUTPase that is elevated in PAH plasma. Neutrophil exosomes from PAH plasma contain increased NE and HERV-K envelope and induce pulmonary hypertension in mice, that is mitigated by the NE inhibitor and antiviral agent, elafin. Thus, elevated HERVs explain pathological neutrophils linked to PAH induction and progression.

immunology↗

bioRxiv2020

Epigenomic reprogramming of repetitive noncoding RNAs and IFN-stimulated genes by mutant KRAS

RAS genes are the most frequently mutated oncogenes in cancer. However, the effects of oncogenic RAS signaling on the noncoding transcriptome are unclear. We analyzed the transcriptomes of human airway epithelial cells transformed with mutant KRAS to define the landscape of KRAS-regulated noncoding RNAs. We found that oncogenic KRAS upregulates noncoding transcripts throughout the genome, many of which arise from transposable elements. These repetitive noncoding RNAs exhibit differential RNA editing in single cells, are released in extracellular vesicles, and are known targets of KRAB zinc-finger proteins, which are broadly down-regulated in mutant KRAS cells and lung adenocarcinomas. Moreover, mutant KRAS induces IFN-stimulated genes through both epigenetic and RNA-based mechanisms. Our results reveal that mutant KRAS remodels the noncoding transcriptome through epigenomic reprogramming, expanding the scope of genomic elements regulated by this fundamental signaling pathway and revealing how mutant KRAS induces an intrinsic IFN-stimulated gene signature often seen in ADAR-dependent cancers.

genomics↗

bioRxiv2019

Loss Of Nuclear Deformability Of Breast Cancer Cells By The Disruption Of Actin Filaments

It is well known that chemical and biomechanical interactions between the nucleus and cytoskeleton are involved in and critical for movement, migration and nuclear positioning of cancer cells. Through nucleo-cytoskeletal coupling, proteins of the LINC complex and the nuclear envelope are capable of transducing cytoplasmic mechanical input across the nuclear membrane; however, their functional importance in the behavior of cancer cells and their nuclei has never been directly tested. In this study, our assumption was that the differences in the malignancies of breast cancer cells are the result of the differences in their nuclear deformation and its expression can be amplified on micropatterned surfaces. Based on this, our hypothesis was that the level of completeness of polymerization of actin filaments can affect nuclear deformability, and as a result, the metastatic capability of the cancer cells. In order to prove this we disrupted the polymerization of the actin filaments by using two drugs, Cytochalasin D and Jasplakinolide, which caused impaired propagation of intracellular forces, prevented nuclear deformation and increased in the expression levels of Lamin A/C and Nesprin-2 in malignant breast cancer cells. Our findings suggest that activity of these two proteins is critical for nucleo-cytoskeletal force transmission. More importantly, actin filament disruption can prevent the distortions in nuclear morphology and as a result avoid the development of cancer metastasis.

bioengineering↗