Technology for diagnostics

RNAs derived from transposable elements and other repeat elements are enriched in the cell-free transcriptome of patients with cancer and can serve as diagnostic signatures.

An assay leveraging the target-specific splinted ligation of DNA probes to generate expression cassettes for the cell-free synthesis of reporter proteins accurately detects nucleic acids at ambient temperature.

A method for the sequential assessment of the physical phenotypes of suspended cells singularized from tissue biopsies by mechanical dissociation allows for rapid diagnoses.

A hydrogel-based metamaterial undergoing shape and optical changes amplified in response to antibody-mediated biorecognition can be used to molecularly profile extracellular vesicles in ascites fluid from patients with cancer.

This Review discusses established and emerging techniques for the multiplexed imaging of isolated tissues and cells and for non-invasive whole-body imaging.

A wearable array of microneedle-based sensors can be used to wirelessly measure the levels of glucose simultaneously with those of alcohol or lactate in the interstitial fluid of volunteers performing common daily activities.

Prospective testing of a clinical fiberscope with a lightproof enclosure for Cerenkov luminescence imaging using five different radiotracers showed satisfactory agreement with standard-of-care nuclear imaging for tumour location.

Benchtop and miniaturized microscopes leveraging single-objective light-sheet illumination allow for volumetric histological imaging of living tissue, in real time and without the need for tissue staining or excision.

A one-step fluorescence assay relying on suboptimal protospacer adjacent motifs for Cas12a detects SARS-CoV-2 RNA in nasopharyngeal samples in less than 20 minutes with a sensitivity comparable to that of RT–qPCR.

Multi-arm junction RNAs integrating motifs for loop-initiated RNA activators enable the execution of molecular logic independent of RNA-input sequence, thus facilitating the design of cell-free diagnostics.

Double-blinded studies show that paper-based diagnostic tests and a companion portable device designed for use in low-resource settings perform well for the diagnosis of the Zika and chikungunya viruses in serum samples.

A self-assembled DNA-based system immobilized on a liquid-gated graphene field-effect transistor can electromechanically detect ultralow levels of unamplified ions, nucleic acids, small molecules and proteins in biofluids.

Optical texture analysis of the retinal nerve fibre layer, via an algorithm integrating thickness and reflectance measurements from standard wide-field optical coherence tomography, outperforms conventional tomographic analysis in the detection of optic neuropathies.

A prototype skin-conformal ultrasonic phased array enables the monitoring of physiological signals from deep tissues, as shown for the measurements of cardiac Doppler waveforms and central and cerebral blood flows.

This Review summarizes the rapidly expanding toolbox of assays for CRISPR-based diagnostics and highlights their point-of-care applications.

Next-generation sequencing of pooled samples tagged with sample-specific molecular barcodes enables the testing, for SARS-CoV-2 RNA, of thousands of nasal or saliva samples in a single run without the need for RNA extraction.

A robot-mounted scanner enables optical coherence tomography, at safe distances, of the eyes of freestanding individuals without operator intervention or head stabilization.

A device that integrates the enrichment and electrochemical detection, in less than one hour, of tumour extracellular vesicles bearing clinically relevant tumour biomarkers accurately classifies patients with colorectal cancer.

Organic electrochemical transistors functionalized with antigen-specific nanobodies can rapidly detect attomolar-to-nanomolar levels of the antigens in complex bodily fluids.

Liquid-gated graphene field-effect transistors anchoring guide RNA–Cas9 complexes can be used to discriminate between single-point mutations in human genomic samples.

Ultrafast ultrasound localization microscopy of intravenously injected microbubbles enables transcranial imaging of deep vasculature in the adult human brain at microscopic resolution and the quantification of haemodynamic parameters.

A renally clearable nanoparticle consisting of a polysaccharide core and an amorphous-like iron oxide shell generates strong T₁ MRI contrast, facilitating the imaging of microvessels, as shown in rodents and rabbits.

A microneedle patch that samples and quantifies target protein biomarkers in interstitial fluid allows for longitudinal monitoring of the levels of a range of disease-relevant biomarkers, as shown in live mice.

Antibody and antibody-avidity assays relying on near-infrared-fluorescence amplification by nanostructured plasmonic gold substrates accurately quantify antibodies to SARS-CoV-2 and to common viruses in human serum and saliva.

An intravenously administered electric-field-sensitive contrast agent for magnetic resonance imaging that crosses the blood–brain barrier improves lesion visualization with high sensitivity and target-to-background ratio in mice.

A one-pot enzymatic assay for the fluorescence detection of RNA accurately and rapidly detects specific viral and bacterial pathogens, as shown for SARS-CoV-2 RNA in clinical samples.

Optical contrast agents using AND-gate logic enhance the specificity and sensitivity of fluorescence-guided imaging in the resection of tumours and in the detection of metastases in mouse models of cancer.

A multiplexed fluorescence-based assay detects seroconversion in individuals infected with SARS-CoV-2 from less than 1 µl of blood as early as the day of the first positive nasopharyngeal nucleic acid test after symptom onset.

Post-mortem histopathological data can be used to classify neuropathologies into six transdiagnostic clusters, and patient membership to these clusters can be predicted from cognitive scores, genotype and protein levels in cerebrospinal fluid.

Label-free imaging of the endogenous pigment lipofuscin at near-infrared and shortwave-infrared wavelengths enables the longitudinal monitoring of liver injury in mice and in biopsied human livers.

A fast and inexpensive point-of-care assay based on CRISPR–Cas13 accurately detects the DNA of opportunistic viruses in blood and urine samples as well as an mRNA marker of renal transplant rejection in urine samples.

An optical-imaging instrument that integrates a visible multispectral imaging system with the detection of near-infrared fluorescence in the first and second windows aids the fluorescence-guided surgical resection of liver tumours in patients.

An electrical biosensor combining CRISPR–Cas9 and a graphene field-effect transistor detects target genes in purified genomic samples at high sensitivity, within 15 minutes, and without the need for amplification.

Nanosensors of the activity of the protease granzyme B, which release a cleaved fluorescence reporter that filters into urine, enable the early diagnosis of acute transplant rejection in mice.

Topically applied imaging nanoprobes for the detection of intracellular mRNA expression from connective tissue growth factor enable the detection of hypertrophic scars and keloids in the skin of small live animals and in ex vivo human skin.

A continuous-acquisition method for reducing artefacts caused by the beating heart and other body motions in cardiovascular magnetic resonance imaging reduces the reliance on electrocardiography triggering and breath holds.

A microfluidic assay that identifies sepsis from a single droplet of diluted blood by measuring the spontaneous motility of neutrophils showed 97% sensitivity and 98% specificity in two independent patient cohorts.

A system that combines positron emission tomography, computed tomography and ultrafast ultrasound allows for simultaneous multi-parametric imaging in animal models.

This Review discusses imaging approaches that benefit from the combination of signals and modalities to enhance patient diagnosis and the monitoring of therapy.

A simple and versatile assay that relies on the bioconjugation capabilities and ultrafast and localized deposition of polydopamine can be plugged into common laboratory bioassays to improve their detection sensitivity by orders of magnitude.

Ultra-broadband optoacoustic mesoscopy implemented in a handheld device enables the visualization of vascular patterns in the dermis and sub-dermis of psoriasis patients, and the quantification of inflammatory biomarkers of psoriasis.

A light-scattering method implemented by using fibre-optic technology that can be directly incorporated into standard vascular-access devices allows for real-time monitoring of blood coagulability in the operating room.

A scanning fibre endoscope, combining reflectance and laser-induced fluorescence emission of intrinsic fluorescent constituents in vascular tissue, provides real-time structural, biochemical and biological images of human atherosclerotic plaques.

This Review covers recent progress on near-infrared fluorescence imaging for preclinical animal studies and clinical diagnostics and interventions.

A hand-powered centrifuge made of two paper discs, string and wooden handles is shown to achieve rotational speeds of 125,000 r.p.m., separate pure plasma from whole blood in less than 1.5 minutes and isolate malaria parasites in 15 minutes.

This Review provides a broad account of the applications of light in imaging, diagnosis, therapy and surgery, and discusses the promise of emerging light-based technologies.

A patient-centred system that leverages the analysis of sweat via wearable sensors may better support the management of patients with substance-use disorders.

DNA-based molecular computation allows for the simultaneous detection of multiple types of biomarker, as shown for the accurate identification of prostate cancer in serum samples on the basis of specific RNAs, proteins and small molecules.

The physical phenotypes of malignant cells in tissue biopsies can be rapidly characterized at high throughput via deformability cytometry after singularizing the cells into a suspension by using a tissue grinder.

By allowing for the visualization of living tissue faster, at higher contrast or with larger fields of view, imaging modalities widely used in research are making inroads into the detection of disease in the human body.

Arrays of ultrasonic transducers arranged hemispherically around the head enable the mapping of haemodynamic changes in the brain via photoacoustic computed tomography at resolutions down to 350 micrometres and 2 seconds.

Volumetric histological imaging of mouse and human tissues without the need for tissue staining or excision can be performed in real time via microscopes leveraging confocally aligned light-sheet illumination.

Lessons being learned about the utility of COVID-19 diagnostics are informing the design, required real-world performance and deployment needs of technologies for the detection of infectious diseases.

Freeze-dried genetic circuits can be integrated with textiles for the detection — colorimetric, or via fluorescence or luminescence — of small molecules and nucleic acids from SARS-CoV-2 and other pathogens.

To facilitate diagnostic radiology at the point of care, improvements in imaging hardware and processing software that raise the signal away from the noise floor are being leveraged toward improving device portability or accessibility.

Epileptic foci in mice can be better visualized with magnetic resonance imaging by using an intravenously administered nanoparticle that crosses the blood–brain barrier and is sensitive to the abnormal electrical activity of foci.

Nanoparticle sensors of the activity of the protease granzyme B detect early T-cell-mediated rejection of transplanted skin grafts in mice via the release of a proteolytically cleaved fluorescence reporter that filters into urine.

Accurate diagnostics need technology — from imaging hardware and image reconstruction to machine learning — to detect markers associated with the cause of disease.

A method that separates overlapping cardiovascular dynamics arising from the beating of the heart, respiration and signal relaxation simplifies and quantifies cardiovascular magnetic resonance imaging.

A microfluidic device for assaying neutrophil motility in blood samples from sepsis patients and a machine-learning algorithm trained with the motility data enable a faster and accurate sepsis diagnosis.

Topically applied spherical nucleic acids targeting an intracellular mRNA biomarker associated with abnormal scarring enable the fluorescent detection of abnormal scars during wound healing.

The combination of ultrafast ultrasound and positron emission tomography–computed tomography enables the simultaneous 3D imaging of anatomy and metabolism at high resolution.

Uniform iron oxide nanoparticles with a hydrodynamic diameter of about 12 nm offer high biocompatibility and diagnostic yield as contrast agents for the magnetic resonance imaging of large animals.

A CRISPR-associated nuclease that can promiscuously cleave RNAs enables a rapid and cheap test for the single-molecule detection and single-base discrimination of nucleic acids.

A universal ‘add-on’ method based on the ultrafast and localized deposition of polydopamine amplifies the sensitivity of a variety of bioassays for clinical diagnostics.

Optoacoustic mesoscopy promises to be a fast and reliable non-invasive method for the diagnosis of psoriasis.

A new endoscope provides high-resolution structural and biochemical videos of human atherosclerotic plaques.

A 20 cent centrifuge made of paper and string and operated by hand can separate plasma from blood in about 90 seconds.