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SURF: Announcements of Opportunity

Below are Announcements of Opportunity posted by Caltech faculty and JPL technical staff for the SURF program. Additional AOs for the Amgen Scholars program can be found here.

Specific GROWTH projects being offerred for summer 2019 can be found here.

Each AO indicates whether or not it is open to non-Caltech students. If an AO is NOT open to non-Caltech students, please DO NOT contact the mentor.

Announcements of Opportunity are posted as they are received. Please check back regularly for new AO submissions! Remember: This is just one way that you can go about identifying a suitable project and/or mentor.

Announcements for external summer programs are listed here.

Students pursuing opportunities at JPL must be
U.S. citizens or U.S. permanent residents.

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Project:  Fabrication of solid–liquid contacts for biosensors using microscale 3D printing
Disciplines:  Applied Physics, Electrical Engineering
Mentor:  Axel Scherer, Bernard Neches Professor of Electrical Engineering, (EAS),
Mentor URL:  (opens in new window)
AO Contact:  Matthew S. Hunt, PhD,
Background:  Implantable biosensors are of rapidly growing interest in medical device applications. Future medical implants aim to provide constant biomarker analysis and feedback to external monitoring devices, leading to substantial insights into patient health. In-vivo environments present challenges such as sensor fouling, complex chemical mixtures, large capillary forces at solid–liquid interfaces, and rejection by the immune system. In response, biosensors can be improved in a number of ways, on a number of scales: (1) On the microscale, sensors can be designed with scaffold structures that promote intergrowth between tissues and electrodes, forming bioactive interfaces that reduce the chance of implant rejection. (2) At the nanoscale, imparting a specific nano-textured surface to the micro-scaffold can maximize the interfacial contact area between solid & liquid while minimizing electrical impedance and providing physical limits on the size of molecules that can be transduced by the sensor. (3) On the molecular level, functionalizing the nano-textured surface with bonded proteins, enzymes and/or aptamers can promote interactions with specific chemicals in the liquid solution.

By engineering at the micro, nano and molecular scales – and harnessing the synergistic effects made available by considering all three – the ultimate goal may be reached: fabricating biosensors that achieve a high level of sensitivity to specific molecules found within a complex chemical solution.
Description:  The scope of this project is to design, fabricate, and measure the impedance of novel, solid–liquid contacts for in-vivo biosensors. The fabrication technique that we will pursue is roughly the nanoscale analogue to the “lost wax” method commonly used to make sculpture art. The student will begin by using 2-photon lithography, a type of microscale 3D printing, to create sensor scaffolds made of polymer. The student will then deposit thin films of metal and/or semiconductor material onto the structure’s surface before plasma-etching out the polymer, thus creating a unique, hollow, high-surface-area, inorganic contact scaffold. Finally, the surfaces will be functionalized with specific aptamers that are expected to selectively interact with target chemicals in a liquid solution.

The student will be involved at each stage – designing, modelling, fabricating, and testing the contacts. For example, the student will (1) draw up novel scaffolds in CAD that can be immediately 3D-printed, (2) work with group members to select deposition materials and decide on deposition strategies that will be used to coat the scaffolds, (3) use COMSOL to simulate how the contacts might perform in an electrochemical test, (4) perform the fabrication her/himself in the cleanroom, with help from lab staff, and then (5) make real measurements on the devices using an electrochemical cell testing apparatus.

To accomplish the project, the student will join both the laboratory of Professor Axel Scherer and the Kavli Nanoscience Institute (KNI) cleanroom, and be co-mentored by Prof Scherer and the KNI’s Assistant Director of Staff Research, Matthew Hunt, PhD. The student will also work closely with the KNI’s Materials & Process Engineer, Alex Wertheim, on the fabrication side of the project, and a selected Scherer Group graduate student on the modelling and measurement sides of the project. Overall, by being involved in the design, modelling, fabrication, and measurement components of the project, the student will experience what it is like to work on a nanoscience project at Caltech as e.g. an Applied Physics, Materials Science, or Engineering graduate student.

***Note: Given that this is a collaboration with the KNI, the student who is chosen for the project will be considered for one of several KNI SURF-the-WAVE Fellowships. Read more about that program here: Consider applying directly for a WAVE Fellowship – separate from or in addition to contacting this project’s co-mentors – if you meet criteria.***
References:  1. “Fabrication of Patterned Integrated Electrochemical Sensors,” a 2015 publication from Axel Scherer’s Caltech Nanofabrication Group (

2. An overview of 2-photon lithography for microscale 3D printing, put together by the Karlsruhe Institute of Technology and Carl Zeiss Microscopy ( (Note: the first 18 slides are on 2-photon lithography, then slides 19-33 are on helium ion microscopy, which is available in the KNI and may be used to characterize structures that are fabricated in this project)

3. “Multiphoton Direct Laser Writing and 3D Imaging of Polymeric Freestanding Architectures for Cell Colonization,” a 2017 publication by Accardo et al (

4. “The fabrication, characterization and application of aptamer-functionalized Si-nanowire FET biosensors,” a 2009 publication by Kim et al (
Student Requirements:  A coursework background in physics, materials science, and/or engineering (e.g. electrical, chemical, mechanical, medical, etc.) is appropriate.

The applicant would strongly benefit from prior experience with: CAD, coding, making measurements with electronic test equipment

The applicant would also benefit from prior experience with (but otherwise would receive expert, concentrated training in): micro/nanoscale characterization (e.g. scanning electron microscopy, atomic force microscopy), 3D printing, thin film deposition & etching techniques
Programs:  This AO can be done under the following programs:

  Program    Available To
       SURF    both Caltech and non-Caltech students 

Click on a program name for program info and application requirements.

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