A Hybrid Titanium-Softmaterial, High-Strength, Transparent Cranial Window for Transcranial Injection and Neuroimaging

Abstract

A transparent and penetrable cranial window is essential for neuroimaging, transcranial injection and comprehensive understanding of cortical functions. For these applications, cranial windows made from glass coverslip, polydimethylsiloxane (PDMS), polymethylmethacrylate, crystal and silicone hydrogel have offered remarkable convenience. However, there is a lack of high-strength, high-transparency, penetrable cranial window with clinical application potential. We engineer high-strength hybrid Titanium-PDMS (Ti-PDMS) cranial windows, which allow large transparent area for in vivo two-photon imaging, and provide a soft window for transcranial injection. Laser scanning and 3D printing techniques are used to match the hybrid cranial window to different skull morphology. A multi-cycle degassing pouring process ensures a good combination of PDMS and Ti frame. Ti-PDMS cranial windows have a high fracture strength matching human skull bone, excellent light transmittance up to 94.4%, and refractive index close to biological tissue. Ti-PDMS cranial windows show excellent bio-compatibility during 21-week implantation in mice. Dye injection shows that the PDMS window has a “self-sealing” to keep liquid from leaking out. Two-photon imaging for brain tissues could be achieved up to 450 µm in z-depth. As a novel brain-computer-interface, this Ti-PDMS device offers an alternative choice for in vivo drug delivery, optical experiments, ultrasonic treatment and electrophysiology recording.

Toward a brighter constellation: multiorgan neuroimaging of neural and vascular dynamics in the spinal cord and brain

“…Similar to the spinal cord implant design described in Ref. 69 , our use of plastic for the implant chamber fabrication makes it more compatible with photoacoustic, ultrasound, and MRI imaging, as well as ultrasound stimulation and radiation therapy. We have not tested nonoptical methods as part of this development process, and additional modifications might be needed to avoid artifacts.…”

Towards a Brighter Constellation: Multi-Organ Neuroimaging of Neural and Vascular Dynamics in the Spinal Cord and Brain

“…Similar to the spinal cord implant design described in Ref. 67 , our use of plastic for the implant chamber fabrication makes it more compatible with photoacoustic, ultrasound, and MRI imaging, as well as ultrasound stimulation and radiation therapy. We have not tested non-optical methods as part of this development process, and additional modifications might be needed to avoid artifacts.…”

Biocompatible Electrical and Optical Interfaces for Implantable Sensors and Devices

“…Taking the first step towards this model, a primitive overlaid cranial window based on 3D printing was engineered and implanted into mice for 21 weeks. In this prototype, the Ti honeycomb is coated with polydimethylsiloxane (PDMS), allowing for optical imaging and transcranial injection [ 42 ].…”

“…Taking the first step towards this model, a primitive overlaid cranial window based on 3D printing was engineered and implanted into mice for 21 weeks. In this prototype, the Ti honeycomb is coated with polydimethylsiloxane (PDMS), allowing for optical imaging and transcranial injection [42]. A silicone dura substitute for long-term optical imaging [39]; (b) schematic drawing of a chamber-based system for neural activity [25]; (c) schematic drawing of a chamber system that simultaneously records µECoG, LFP, and spiking activity [40]; (d) a proposal for large-area multi-functional artificial dura system [41].…”