Acoustofluidic Detection and Disease Diagnosis

Acoustic separation and concentration of exosomes for nucleotide detection: ASCENDx

Figure: Operating mechanism of the ASCENDx platform.

(A) Acoustic streaming within a water droplet deforms the liquid-air interface, causing the droplet to spin. When a disc is placed on top of the droplet, this streaming phenomenon causes the disc to rotate, leading to the concentration and separation of micro/nano objects. (B) Device photo and (C) schematic of the acoustofluidic disc unit of the ASCENDx platform. A water droplet is placed within a PDMS ring and situated between four SPFTs. A small disc with microfluidic structures patterned into its surface is placed atop the droplet. As SAWs propagate into the droplet, a helical vortex is formed, causing the droplet-disc system to rotate. (D) As the disc rotates, larger particles move to the ends of the channel first. In this region, we have immobilized bimetallic nanostars to facilitate SERS analysis of the concentrated sample. The enriched sample can be removed via pipette for PCR analysis and integration with our point-of-care miRNA assay.

Efficient isolation and analysis of exosomal biomarkers hold transformative potential in biomedical applications. However, current methods are prone to contamination and require costly consumables, expensive equipment, and skilled personnel. Here, we introduce an innovative spaceship-like disc that allows Acoustic Separation and Concentration of Exosomes and Nucleotide Detection: ASCENDx. We created ASCENDx to use acoustically driven disc rotation on a spinning droplet to generate swift separation and concentration of exosomes from patient plasma samples. Integrated plasmonic nanostars on the ASCENDx disc enable label-free detection of enriched exosomes via surface-enhanced Raman scattering. Direct detection of circulating exosomal microRNA biomarkers from patient plasma samples by the ASCENDx platform facilitated a diagnostic assay for colorectal cancer with 95.8% sensitivity and 100% specificity. ASCENDx overcomes existing limitations in exosome-based molecular diagnostics and holds a powerful position for future biomedical research, precision medicine, and point-of-care medical diagnostics.

Cellular Immunity Analysis by Modular Acoustofluidic Platform: CIAMAP

Figure: Schematic of CIAMAP-facilitated cell pairing and immunity mechanism exploration.

(A) Cytotoxicity of an NK92 cell when in contact with the K562 cell in a natural microenvironment. Through MHC-1 and NKG2D binding, the NK92 cell is activated through two signaling pathways. The first pathway is perforin-independent; cytokine release induces target cell apoptosis. Represented is IFN-γ, which needs mRNA to be up-regulated before more cytokines can be expressed. The other signaling pathway is perforin-dependent cytotoxicity, which is posttranscriptionally regulated. After being activated, stored perforins and granzymes will be released directly to attack tumor cells. In the doxorubicin environment, doxorubicin inhibits both perforin-dependent and perforin-independent signaling pathways and triggers TRAIL-mediated apoptosis. Doxorubicin also directly attacks tumor cells, increasing NK92 cellular cytotoxicity. (B to E) Schematic of the CIAMAP. (B) Schematic showing the twin-signal–triggered droplet sorting function of the acoustofluidic cell pairing module (i). (ii) Simulation results show the mechanism of acoustofluidic sorting. The acoustic radiation force (F_R) pushes the target droplet to the pressure node. (C) Overview of the CIAMAP comprises the acoustofluidic cell pairing module and interlocked multi-well plate module. (D) The cross-sectional structure of the interlocked multi-well plate module. (E) The upward microwells enable droplet loading (i) and effective collection after microscopic detection (ii). CIAMAP technology can enrich cell pair droplets, monitor real-time cell states, and perform intact collections of droplets for downstream analysis.

The study of molecular mechanisms at the single-cell level holds immense potential for enhancing immunotherapy and understanding neuroinflammation and neurodegenerative diseases by identifying previously concealed pathways within a diverse range of paired cells. However, existing single-cell pairing platforms have limitations in low pairing efficiency, complex manual operation procedures, and single-use functionality. Here, we report a multiparametric cellular immunity analysis by a modular acoustofluidic platform: CIAMAP. This platform enables users to efficiently sort and collect effector-target (i.e., NK92-K562) cell pairs and monitor the real-time dynamics of immunological response formation. Furthermore, we conducted transcriptional and protein expression analyses to evaluate the pathways that mediate effector cytotoxicity toward target cells, as well as the synergistic effect of doxorubicin on the cellular immune response. Our CIAMAP can provide promising building blocks for high-throughput quantitative single-cell level coculture to understand intercellular communication while also empowering immunotherapy by precision analysis of immunological synapses.

Acoustofluidic multimodal diagnostic system for Alzheimer's disease

Figure: Schematic illustration of the acoustofluidics-based diagnostic system (ADx) for Alzheimer's disease. Liquid biopsy is employed to test AD patients' plasma samples for circulating protein biomarkers such as Aβ and Tau (A–B). An acoustofluidic separation chip is employed for removing contaminating bioparticles and isolating AD-specific biomarkers from patient plasma (C). An acoustofluidic microreactor (D) is employed for developing functional nanoarray-based SERS (E) and electrochemical immunosensor (F).

Alzheimer's disease (AD) is a progressive and irreversible neurodegenerative brain disorder that affects tens of millions of older adults worldwide and has significant economic and societal impacts. Despite its prevalence and severity, early diagnosis of AD remains a considerable challenge. Here we report an integrated acoustofluidics-based diagnostic system (ADx), which combines triple functions of acoustics, microfluidics, and orthogonal biosensors for clinically accurate, sensitive, and rapid detection of AD biomarkers from human plasma. We design and fabricate a surface acoustic wave-based acoustofluidic separation device to isolate and purify AD biomarkers to increase the signal-to-noise ratio. Multimodal biosensors within the integrated ADx are fabricated by in-situ patterning of the ZnO nanorod array and deposition of Ag nanoparticles onto the ZnO nanorods for surface-enhanced Raman scattering (SERS) and electrochemical immunosensors. We obtain the label-free detections of SERS and electrochemical immunoassay of clinical plasma samples from AD patients and healthy controls with high sensitivity and specificity. We believe that this efficient integration provides promising solutions for the early diagnosis of AD.