Antibody Conjugate Assembly on Ultrasound-Confined Microcarrier Particles

Abstract

Bioconjugates are important next-generation drugs and imaging agents. Assembly of these increasingly complex constructs requires precise control over processing conditions, which is a challenge for conventional manual synthesis. This inadequacy has motivated the pursuit of new approaches for efficient, controlled modification of high-molecular-weight biologics such as proteins, carbohydrates, and nucleic acids. We report a novel, hands-free, semiautomated platform for synthetic manipulation of biomolecules using acoustically responsive microparticles as threedimensional reaction substrates. The microfluidic reactor incorporates a longitudinal acoustic trap that controls the chemical reactions within a localized acoustic field. Forces generated by this field immobilize the microscale substrates against the continuous flow of participating chemical reagents. Thus, the motion of substrates and reactants is decoupled, enabling exquisite control over multistep reaction conditions and providing high-yield, high-purity products with minimal user input. We demonstrate these capabilities by conjugating clinically relevant antibodies with a small molecule. The on-bead synthesis comprises capture of the antibody, coupling of a fluorescent tag, product purification, and product release. Successful capture and modification of a fluorescently labeled antibody are confirmed via fold increases of 49 and 11 in the green (antibody)-and red (small-molecule dye)-channel median intensities determined using flow cytometry. Antibody conjugates assembled on acoustically responsive, ultrasound-confined microparticles exhibit similar quality and quantity to those prepared manually by a skilled technician.

A thermoelectrically stabilized aluminium acoustic trap combined with attenuated total reflection infrared spectroscopy for detection of Escherichia coli in water

“…hyperspectral imaging). In addition, the recently reported possibility of performing antibody labelling with the assistance of ultrasound particle manipulation on a chip, 25 combined with on-chip mid-IR sensing 51,52 points to possibly automating the overall sample handling scheme, including antibody labelling, in addition to indicating room for further miniaturization. Mid-IR sensing in general holds the potential for label-free sensing by either directly measuring bacteria or their intrinsic β-D-galactosidase or β-D glucuronidase enzyme activity.…”

“…13,14 Acoustic trapping has previously been used to perform noncontact bead-based assays as well as bacteria trapping using seed particles. [25][26][27][28] US particle manipulation has been paired with near infrared, 29 attenuated total reflection Fouriertransform mid-infrared (ATR-FTIR) spectroscopy 30,31 and Raman spectroscopy 32 to enhance process analytical spectroscopy as well as with fluorescence and surfaceenhanced Raman spectroscopy. 33 Mid-IR spectroscopy allows rapid, non-destructive, and label-free acquisition of moleculespecific information by probing molecular vibrations.…”

Dynamic measurement of the acoustic streaming time constant utilizing an optical tweezer

“…In recent years, acoustofluidics has provided many powerful tools. Due to being contactless, label-free, and biocompatible [1][2][3][4][5], acoustofluidic manipulation can be used in medical applications for cancer research [1][2][3][4], Alzheimer research [5], targeted drug delivery [6], and for pumping medical fluids [7]. In addition, there are biological [8,9] and engineering applications (e.g., micropumping [7,[10][11][12]).…”

Real-Time Detection and Control of Microchannel Resonance Frequency in Acoustic Trapping Systems by Monitoring Amplifier Supply Currents

“…Acoustic trapping is achieved by selective particle transport to the acoustic standing wave node or antinode, depending on the acoustic contrast of the particle versus the medium, as determined by the mass density, compressibility, and size of particles . Given the opportunities it presents for particle separation from heterogeneous samples, acoustophoresis is poised to impact the fields of sample preparation, , cell micropatterning, three-dimensional (3D) printing, , nanomaterial synthesis, and cell phenotypic elucidation …”

“…14 Acoustic trapping is achieved by selective particle transport to the acoustic standing wave node or antinode, depending on the acoustic contrast of the particle versus the medium, as determined by the mass density, compressibility, and size of particles. 15 Given the opportunities it presents for particle separation from heterogeneous samples, acoustophoresis is poised to impact the fields of sample preparation, 16,17 cell micropatterning, 18 three-dimensional (3D) printing, 19,20 nanomaterial synthesis, 21 and cell phenotypic elucidation. 22 The most common configurations use an underlying piezoelectric transducer to set up bulk acoustic waves within a microchannel 23 so that the resulting standing wave can spatially localize particles at distinct positions along the channel width under resonance conditions, 24 with orthogonal flow used to remove nontrapped particles.…”