# 3D-printed syringe holder with synchronized push-pull action

## TL;DR

A 3D-printed device called Push2Pull allows precise and simultaneous fluid exchange using two syringes, without the need for expensive equipment.

## Contribution

The Push2Pull syringe holder is a low-cost, open-source, and electricity-free device for synchronized fluid handling.

## Key findings

- The device achieves fluid exchange accuracy within ±2%v/v across the full travel range.
- It is compatible with syringes from 1 to 60 mL and works without electricity or additional hardware.
- CFD simulations confirmed its efficiency for various practical applications.

## Abstract

Controlled liquid exchange is a fundamental requirement for numerous biological and chemical experimental protocols. However, achieving constant-volume exchange often requires electronic syringe pumps that are cost-prohibitive and time-consuming to set up in a push-pull configuration. To address these limitations, we developed the Push2Pull syringe holder, a simple 3D-printed device that mechanically synchronizes two syringes to simultaneously add and extract equal fluid volumes. This device is compatible with standard disposable syringes from 1 to 60 mL in size and operates without electricity or additional hardware, making it ideal for both laboratory and field settings. Validation experiments demonstrate an exchange accuracy within ±2%v/v across the whole travel range, while fluid exchange efficiency was calculated for various use cases using CFD simulations. The Push2Pull syringe holder offers an accessible, open-source solution for precise fluid handling, for a material cost of less than $10.

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