David John Collins

David John Collins
University of Melbourne | MSD · Department of Biomedical Engineering

PhD

About

105
Publications
23,862
Reads
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2,335
Citations
Additional affiliations
December 2018 - present
University of Melbourne
Position
  • Lecturer
September 2017 - September 2018
Massachusetts Institute of Technology
Position
  • PostDoc Position
February 2017 - May 2017
Singapore University of Technology and Design
Position
  • Lecturer
Description
  • Course Lead for Aerodynamics (30.205)
Education
August 2005 - December 2009
University of Melbourne
Field of study
  • Biomedical Engineering

Publications

Publications (105)
Article
Full-text available
In single-cell analysis, cellular activity and parameters are assayed on an individual, rather than population-average basis. Essential to observing the activity of these cells over time is the ability to trap, pattern and retain them, for which previous single-cell-patterning work has principally made use of mechanical methods. While successful as...
Article
Full-text available
Micrometer scale acoustic waves are highly useful for refined opto-mechanical and acoustofluidic manipulation, where these fields are spatially localized along the transducer aperture but not along the acoustic propagation direction. In the case of acoustic tweezers, such a conventional acoustic standing wave results in particle and cell patterning...
Article
Full-text available
Acoustic fields have been widely used for manipulation of particles and cells within microfluidic systems. In this Letter, we explore a novel acoustofluidic phenomenon for particle patterning and focusing, where a periodic acoustic pressure field is produced parallel to internal channel boundaries with the imposition of either a traveling or standi...
Article
Full-text available
Recent research has shown that interactions between acoustic waves and microfluidic channels can generate microscale interference patterns with the application of a traveling surface acoustic wave (SAW), effectively creating standing wave patterns with a traveling wave. Forces arising from this interference can be utilized for precise manipulation...
Article
Full-text available
Acoustic waves can be used to accurately position cells and particles and are appropriate for this activity owing to their biocompatibility and ability to generate microscale force gradients. Such fields, however, typically take the form of only periodic one or two-dimensional grids, limiting the scope of patterning activities that can be performed...
Article
Full-text available
Surface acoustic wave (SAW) micromanipulation offers modularity, easy integration into microfluidic devices and a high degree of flexibility. A major challenge for acoustic manipulation, however, is the existence of a lower limit on the minimum particle size that can be manipulated. As particle size reduces, the drag force resulting from acoustic s...
Article
We demonstrate a sawtooth-based metasurface approach for flexibly orienting acoustic fields in a microfluidic device driven by surface acoustic waves (SAW), where sub-wavelength channel features can be used to arbitrarily steer acoustic fringes in a microchannel. Compared to other acoustofluidic methods, only a single travelling wave is used, the f...
Article
Recent studies have demonstrated that periodic time-averaged acoustic fields can be produced from traveling surface acoustic waves (SAWs) in microfluidic devices. This is caused by diffractive effects arising from a spatially limited transducer. This permits the generation of acoustic patterns evocative of those produced from standing waves, but in...
Article
Full-text available
Both the scarcity and environmental impact of disposable face masks, as in the COVID-19 pandemic, have instigated the recent development of reusable masks. Such face masks reduce transmission of infectious agents and particulates, but often impact a user's ability to be understood when materials, such as silicone or hard polymers, are used. In this...
Article
Acoustic fields are ideal for micromanipulation, being biocompatible and with force gradients approaching the scale of single cells. They have accordingly found use in a variety of microfluidic devices, including for microscale patterning, separation, and mixing. The bulk of work in acoustofluidics has been predicated on the formation of standing w...
Article
Full-text available
Biofabrication is a fast-evolving and multi-disciplinary field, harnessing the benefits and capabilities of additive manufacturing and complementary bioassembly techniques at the intersection of biology and engineering. Biofabrication is promising for printing of transplantable tissues, though near-term applications in practice include biomimetical...
Article
Full-text available
Filtering facepiece respirators (FFRs) and medical masks are widely used to reduce the inhalation exposure of airborne particulates and biohazardous aerosols. Their protective capacity largely depends on the fraction of these that are filtered from the incoming air volume. While the performance and physics of different filter materials have been th...
Article
Full-text available
The study of neurons is fundamental for basic neuroscience research and treatment of neurological disorders. In recent years ultrasound has been increasingly recognized as a viable method to stimulate neurons. However, traditional ultrasound transducers are limited in the scope of their application by self-heating effects, limited frequency range a...
Article
Full-text available
Creating defined nonuniform acoustic fields, with particle capture locations beyond the grids and lines that are typically generated, has a range of applications in microfluidic systems. In this work, we use a unique interaction between polydimethylsiloxane (PDMS) channel geometries and a travelling substrate wave to explore the creation of nonunif...
Article
Acoustic fields have shown wide utility for micromanipulation, though their implementation in microfluidic devices often requires accurate alignment or highly precise channel dimensions, including in typical standing surface acoustic wave (SSAW) devices and resonant channels. In this work we investigate an approach that permits continuous microscal...
Article
Full-text available
In article number 2000462, David J. Collins, Ye Ai, and co‐workers demonstrate the generation of robust nanoscale force gradients from interactions between MHz acoustic waves and nanocavities, which enables massively multiplexed sub‐micron particle trapping within these nanocavities at the single‐particle level.
Article
Nanoacoustic fields are a promising method for particle actuation at the nanoscale, though THz frequencies are typically required to create nanoscale wavelengths. In this work, the generation of robust nanoscale force gradients is demonstrated using MHz driving frequencies via acoustic‐structure interactions. A structured elastic layer at the inter...
Article
Full-text available
Surface acoustic waves can induce force gradients on the length scales of micro- and nanoparticles, allowing precise manipulation for particle capture, alignment and sorting activities. These waves typically occupy a spatial region much larger than a single particle, resulting in batch manipulation. Circular arc transducers can focus a SAW into a n...
Conference Paper
Calcium imaging is a powerful tool for observing the activity of neurons and neural tissue. For neuronal prostheses, calcium imaging can be used to monitor the efficacy of electrical stimulation and quantify the electrically stimulated interaction between the implant and cells. Although different techniques for retinal staining exist, most are inef...
Article
Full-text available
Droplet-based single cell sequencing has emerged as a very powerful tool to study the cellular heterogeneity in diseased tissues for a variety of biological problems. However, the current droplet generation with single particle and cell encapsulation is a random process and suffers from a low yield that is unable to fulfill the high-throughput anal...
Article
Full-text available
Acoustic forces arising from high-frequency surface acoustic waves (SAW) underpin an exciting range of promising techniques for non-contact manipulation of fluid and objects at micron scale. Despite increasing significance of SAW-driven technologies in microfluidics, the understanding of a broad range of phenomena occurring within an individual SAW...
Article
Full-text available
Acoustofluidics has a strong pedigree in microscale manipulation, with particle and cell separation and patterning arising from acoustic pressure gradients. Acoustic waveguides are a promising candidate for localizing force fields in microfluidic devices, for which computational modelling is an important design tool. Meshed finite element analysis...
Article
Full-text available
Fluorescence activated cell sorting (FACS) has become an essential technique widely exploited in biological studies and clinical applications. However, current FACS systems are quite complex, expensive, bulky, and possess potential sample contamination and biosafety issues due to the generation of aerosols in an open environment. Microfluidic techn...
Article
Full-text available
Correction for 'Selective particle and cell capture in a continuous flow using micro-vortex acoustic streaming' by David J. Collins et al., Lab Chip, 2017, DOI: 10.1039/c7lc00215g.
Article
Fluorescence Activated Cell Sorting (FACS) is an essential technique widely used in biomedical analyses.Microfluidics, benefiting at its low power and sample consumption, has enabled miniaturization of the existing bulk FACS equipment into cost-effective and portable devices. However, these devices still have limited efficiency and biocompatibility...
Article
Full-text available
Periodic pattern generation using time-averaged acoustic forces conventionally requires the intersection of counterpropagating wave fields, where suspended micro-objects in a microfluidic system collect along force potential minimizing nodal or antinodal lines. Whereas this effect typically requires either multiple transducer elements or whole chan...
Article
Full-text available
Acoustic streaming has emerged as a promising technique for refined microscale manipulation, where strong rotational flow can give rise to particle and cell capture. In contrast to hydrodynamically generated vortices, acoustic streaming is rapidly tunable, highly scalable and requires no external pressure source. Though streaming is typically ignor...
Conference Paper
Full-text available
Construction and sensing within malleable interfaces is usually limited by a number of constraints. Building the interface from diverse combinations of conductive and nonconductive soft materials, such as fabrics or foams combined with various sensors, complicates the manufacturing process and offers limited options in shaping. In this paper we pro...
Article
Microscale separation is an important process for many medical diagnostics and biological analysis applications. Acoustic based microparticle manipulation has the advantages of low power consumption and good biocompatibility, and has been widely exploited in label-free particle and cell separation. However, typically applied forces scale with incre...
Article
Full-text available
In this work, we discuss and demonstrate the principle features of surface acoustic wave (SAW) aerosol generation, based on the properties of the fluid supply, the acoustic wave field and the acoustowetting phenomena. Furthermore, we demonstrate a compact SAW-based aerosol generator amenable to mass production fabricated using simple techniques inc...
Article
Full-text available
Despite increasing demand in the manipulation of nanoscale objects for next generation biological and industrial processes, there is a lack of methods for reliable separation, concentration and purification of nanoscale objects. Acoustic methods have proven their utility in contactless manipulation of microscale objects mainly relying on the acoust...
Article
Full-text available
Most microfluidics-based sorting methodologies utilize size differences between suspended micro-objects as the defining characteristic by which they are sorted. Sorting based on mechanical properties, however, would provide a new avenue for sample preparation, detection and diagnosis for a number of emerging biological and medical analyses. In this...
Article
Full-text available
Manipulation of cells by acoustic forces in a continuous flow offers a means to sort on the basis of physical properties in a contactless, label-free and biocompatible manner. Many acoustic sorting systems rely on either standing waves or travelling waves alone and require specific exposure times to the acoustic field, fine-tuned by manipulating th...
Article
Acoustic forces have been widely used to control microparticles within microfluidic systems. Such acoustofluidic systems have been very successful in tasks such as cell sorting, however, to date efforts have been mostly limited to single phase systems. Just as the contrast in acoustic impedance between a fluid and suspended particle means that acou...
Article
Full-text available
Surface acoustic wave (SAW) based particle manipulation is contactless, versatile, non-invasive and biocompatible making it useful for biological studies and diagnostic technologies. In this work, we present a sensitive particle sorting system, termed the virtual membrane, in which a periodic acoustic field with a wavelength on the order of particl...