Company: PFSA
Filing Date: 2025-10-29
Form Type: 424B3
Source: 0001213900-25-103174
Chunk: 191

Company: Profusa, Inc.
Filing Date: 2025-10-29
Form: 424B3
Chunk 191
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 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 the body. This device is also designed to have the capability to measure multiple wavelengths of
light allowing for the capture of changes in tissue optical properties and reference chemistry signals, providing input to the data algorithm
to potentially correct for variability of subject tissue types and individuals change in tissue properties over time. Additionally, the
reader is designed to be able to include thermistors, or temperature-sensitive resistors, and motion detectors, enabling the collection
of additional parameters the algorithm may use to increase the accuracy of the analyte measurement. The externally worn device is designed
to be a durable component of the system and can be reused for multiple sensor injections.

<div align='center'>108</div>

| ● | Data Algorithm |

Software algorithms operating in firmware
and mobile applications compute clinically relevant values based on optical signals and temperature measurements provided by the reader
hardware. Lumee Oxygen uses an oxygen sensor whose optical intensity, after excitation from an LED, decreases at a rate that is a function
of tissue oxygen. The hardware is designed to provide rapid optical intensity measurements. The firmware fits the decrease in intensity
to a model whose coefficients represent the oxygen intensity. The firmware produces a Lumee Oxygen Index (LOI) value every few seconds
and the tablet application visualizes the data and determines the percent change over time. The glucose hydrogel is an intensity-based
system with two dyes: a reference dye whose intensity is independent of glucose and other chemical properties of its environment, and
a glucose dye whose intensity after excitation changes predictably with glucose concentration. The ratio of the glucose and reference
intensity provides an approximation of the glucose signal. The glucose system is designed to use several wavelengths of light from defined
LED sources and optical detectors. Every measurement sample includes 84 unique optical measurements that form a data set that is used
to determine the glucose dye intensity, tissue