Company: PFSA
Filing Date: 2025-08-29
Form Type: S-1
Source: 0001213900-25-082672
Chunk: 164

Company: Profusa, Inc.
Filing Date: 2025-08-29
Form: S-1
Chunk 164
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 bound or unbound. The hydrogel sensors are devoid of any electronics or power source, and are simply composed of the hydrogel scaffolding and the fluorescence sensing chemistry. Depending on the sensor type, Profusa may also imbed a reference chemistry for reference purposes during data processing. The hydrogel sensor measures approximately 400 microns in diameter by 3 millimeters in length and is injected subcutaneously via a hypodermic needle injection at a depth of 2 – 6 millimeters from the surface. Upon injection, the sensor is designed to be integrated as a part of the tissue and is not noticeable. As this sensor is passive in nature, while the binding and unbinding of the analyte of interest is constantly occurring, data from the sensor is not actively broadcasted outside of the body until a reader (described below) is placed on the skin over the sensor. 103 By “decoupling the sensor and the reading elements,” we believe that our approach has a few major advantages: 1.The cost of the system is quite low as the sensors are low cost to manufacture and the more expensive reader component can be reused through multiple sensor injections; 2.The act of data acquisition is controlled by the user and action is secure; 3.The sensor deployment is a common hypodermic needle procedure that can be performed by healthcare professionals across a variety of common settings; and 4.The sensor functionality lifetime is limited by the stability of the fluorescence molecule and not by the foreign body response, which translates into months of functionality. • Reusable Reader An optical reader has been developed to be worn on the skin above the sensor and is designed to interrogate and gather sensor signal for data processing. This optical reader has a small wearable form factor dimensions of the oxygen reader and is worn on the skin via a double -sidedmedical grade adhesive. The readers are rechargeable via conductive charging and currently have a functional lifetime of 24 hours on a single charge in the case of Lumee Oxygen. When a datapoint is desired, the firmware of the reader instructs the device to pulse a light source shining an excitation light of a specific wavelength to illuminate the sensor under the skin. The return fluorescent light from the sensor is then detected by the reader via a series of photo detectors and the data is captured for algorithm processing. By continuously pulsing the light and capturing the return signal from the hydrogel sensor, the reader is designed to be able to collect a stream of data allowing for the continuous monitoring of the biochemistry inside