The company will issue 1.3mln shares worth of convertible notes, with a fixed price of US$0.28 per share, and warrants, at an exercise price of US$0.40 per share for the additional share purchases.
One or more additional closings are expected in the near future.
Pressure, which provides technology for the preparation stage of lab testing in life science research, netted US$670,500 in cash after taking into account fees related to the offering.
Richard Schumacher, president and chief executive, said the funds will be used for a number of tasks, including to bolster the number of staff in its marketing and sales divisions.
It will use the remainder to boost the firm’s manufacturing capacity, ready for a potential up-listing to a national regulated exchange in the near future, and will enable the company to retire all variable rate convertible debt that had been previously taken on.
PBIO is developing pressure cycling technology-based instruments and consumables for a number of areas in scientific research, including drug discovery and design, cancer and other disease/disorder detection, and the analysis of microorganism populations in soil.
Last week, shares in the stock advanced after it reported a 56% jump in third-quarter revenue, buoyed by solid growth in products and services and grant revenue.
Revenue increased to $580,334 in the July-to-September quarter from $372,545 a year earlier, the South Easton, Massachusetts-based company said.
"We believe PBI has reached a major inflection point," chief executive Schumacher had said.
"We also believe the growth and success shown in 2015 is a bellwether of things to come, and that 2016 will provide breakout well beyond those realized in 2015."
Shares in the group eased 3.12% to US$0.23.