# Controlling biomicrofluidic device surface chemistry using smart surface-segregating zwitterionic polymers

> **NIH NIH R21** · TUFTS UNIVERSITY MEDFORD · 2021 · $250,753

## Abstract

Abstract
The use of microfluidic devices in biomedical research through tissue culture experiments
(tissues/organs-on-chips) and biological separations is growing rapidly. Polydimethylsiloxane (PDMS)
has been the most popular material for microfluidics due to its feature replication down to the nanoscale,
flexibility, gas permeability for oxygenation, and low cost. Yet, the hydrophobicity of PDMS leads to the
adsorption of macromolecules (e.g. proteins) and hydrophobic compounds (e.g. Class II & IV drugs) on
device surfaces. This curtails its use for drug screening in “organs-on-chips”, and other applications.
Current technologies to improve PDMS surface hydrophilicity involve added processing steps and/or do
not create surfaces that remain hydrophilic for long periods. They also cannot simultaneously incorporate
functional groups to promote binding of specific biomolecules and create bioactive surfaces. This
hampers their large-scale implementation and adoption. Our long-term goal is to develop smart materials
to improve the precision, robustness, and functionality of biomicrofluidics while keeping their large-scale
fabrication simple, facile, and efficient. In this application, we detail a novel, simple technology to modify
PDMS via rationally designed smart polymers that, when blended with PDMS during device manufacture,
spontaneously segregate to surfaces and create a <1 nm layer when in contact with aqueous solutions
that prevents non-specific adsorption of organic and biomolecules, yet can be functionalized to control
specific binding for a given application. Our methods are fully compatible with existing PDMS device
manufacture protocols without any additional processing steps. To achieve this immediate goal, we aim
to develop novel CP additives for “Smart Copolymer Addition for Modification of PDMS Surfaces”
(SCAMPS), specifically highly branched CPs of PDMS with zwitterionic (ZI) groups (Aim 1), with the
addition of functional groups that mediate specific binding (Aim 2). We will design and synthesize several
members of each smart copolymer class, prepare samples from their blends with PDMS, and
characterize them in terms of their mechanical properties, optical clarity, surface chemistry, and tendency
to adsorb proteins and small molecule drugs. For functionalized samples, we will also measure the
selective adhesion of desired solutes (e.g. avidin on biotin-functional surfaces) and cell types. We will
also test the stability and chemistry of the surface upon long-term storage in air and water. We will prepare
microfluidic devices from most promising candidates and validate their performance in long-term cell
culture experiments. We expect the technologies we develop to improve the accessibility of microfluidics
to end users (patients, researchers, drug industry) by providing a low-cost and user-friendly approach to
the fabrication of reliable biomicrofluidics.

## Key facts

- **NIH application ID:** 10193245
- **Project number:** 1R21GM141683-01
- **Recipient organization:** TUFTS UNIVERSITY MEDFORD
- **Principal Investigator:** Ayse Asatekin
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $250,753
- **Award type:** 1
- **Project period:** 2021-08-01 → 2023-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10193245

## Citation

> US National Institutes of Health, RePORTER application 10193245, Controlling biomicrofluidic device surface chemistry using smart surface-segregating zwitterionic polymers (1R21GM141683-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10193245. Licensed CC0.

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