A MEMS intracranial pressure device for monitoring brain injuries and disorders

描述（由申请人提供）：颅内压（ICP）监测是有效治疗脑损伤（例如创伤性脑损伤（TBI））和脑脊液流出障碍（例如脑积水）患者的基本诊断工具。 临床试验表明，ICP监测降低了死亡率，并最大限度地减少了继发性损伤。 到目前为止，各种ICP监测系统在准确监测ICP方面已经取得了成功，但是：（a）它们具有高感染概率（高达15%），（B）它们不允许长期ICP监测，以及（c）它们不兼容MRI（磁共振成像）。 利用微机电系统（MEMS）领域的最新发展，我们提出了一种“颅内压微棒”（IP<S）技术，克服了上述限制。 该技术基于完全可植入（无电缆）的光学MEMS设备，该设备对ICP变化进行“颜色”编码：ICP被转换为近红外（NIR）波长的比率光信号。 该装置由一个可调微透镜组成，将光聚焦到量子点双层中。 这两层中的每一层都含有独特波长的NIR量子点。 当ICP改变时，微透镜的焦距改变，导致两个波长的比率强度改变。 非植入式便携式光学单元用于激发微透镜/量子点组件并收集发射的NIR光谱。 无电子（因此无电源）的IP<S设备能够实现长时间的ICP监测，消除感染风险，允许患者舒适和移动，并且它是MRI兼容的。 我们提出了具有以下具体目标的研究计划：（a）可调微透镜/量子点双层组件的优化：可调微透镜/量子点双层组件将在微透镜收集效率、内部微透镜压力分辨率、动态范围和量子点双层厚度方面进行优化;（B）集成IPS器件的微制造和测试：将微制造一个IP原型，并建立其规格（ICP范围、分辨率、时间响应）;（c）体外研究：我们将通过将集成装置浸入含有脑脊髓液（CSF）的浴中进行体外研究。 将对CSF压力进行外部调整，以代表真实的ICP监测场景，并将确定器械的长期耐久性和零点漂移。 该技术将有助于有效地管理和治疗脑损伤和脑脊液流出障碍，并将开创可植入和无电源的小型化设备的发展，这些设备可用于各种压力监测生物医学应用。 公共卫生相关性：颅内压（ICP）监测是评估创伤性脑损伤（TBI）、先天性或获得性脑积水或肿块病变患者病理状况的重要诊断工具。 这项工作的目的是开发一种新的植入式ICP监测设备，将提供更好的管理和有效的治疗ICP升高的患者。

DESCRIPTION (provided by applicant): Intracranial pressure (ICP) monitoring is an essential diagnostic tool for the efficient treatment of patients with brain injuries (e.g. traumatic brain injuries (TBIs)) and cerebrospinal fluid outflow disorders (e.g. hydrocephalus). Clinical trials have shown that ICP monitoring decreases the mortality rate and minimizes secondary injuries. Various ICP monitoring systems have been successful so far in accurately monitoring ICP, but: (a) they have high probability of infection (up to 15%), (b) they do not allow long-term ICP monitoring and (c) they are not MRI (Magnetic Resonance Imaging) compatible. Taking advantage of recent developments in the MicroElectroMechanical Systems (MEMS) field, we propose an 'Intracranial Pressure Micro Stick' (IP<S) technology that overcomes the aforementioned limitations. The technology is based on a fully implantable (cable-free), optical, MEMS device that 'color' codes ICP changes: ICP is converted to a ratiometric optical signal in the near infrared (NIR) wavelength. The device consists of a tunable microlens that focuses light into a quantum-dot bilayer. Each of the two layers contains NIR quantum dots of a unique wavelength. The focal length of the microlens is altered when the ICP changes, resulting in a change in the ratiometric intensity of the two wavelengths. A non-implantable, portable optical unit is used to excite the microlens/quantum dot assembly and collect the emitted NIR spectrum. The electronic- free (and thus power-free) IP<S device enables prolonged ICP monitoring, eliminates the risk of infection, allows patient's comfort and mobility and it is MRI compatible. We propose a research plan with the following specific aims: (a) Optimization of the tunable microlens/quantum dot bilayer assembly: the tunable microlens/quantum dot bilayer assembly will be optimized with respect to the microlens collection efficiency, internal microlens pressure resolution, dynamic range, and quantum dot bilayer thickness; (b) Microfabrication and testing of the integrated IP<S device: an IP<S prototype will be microfabricated and its specifications will be established (ICP range, resolution, time response); (c) In-vitro Studies: We will perform in vitro studies by immersing the integrated device in a bath containing cerebrospinal fluid (CSF). The pressure of the CSF will be externally adjusted to represent a real ICP monitoring scenario and the long term durability and zero drift of the device will be determined. The proposed technology will help in efficiently managing and treating brain injuries and CSF outflow disorders, and it will inaugurate the development of implantable and power-free, miniaturized devices that can be used in a variety of pressure monitoring biomedical applications. PUBLIC HEALTH RELEVANCE: Intracranial pressure (ICP) monitoring is an important diagnostic tool for accessing the pathological condition of patients with traumatic brain injury (TBI), congenital or acquired hydrocephalus or mass lesions. This work aims to develop a new class of implantable ICP monitoring devices that will provide better management and efficient treatment of patients with elevated ICP.